Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Redrock Stonefly as Endangered or Threatened, 46251-46266 [2011-19447]
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Federal Register / Vol. 76, No. 148 / Tuesday, August 2, 2011 / Proposed Rules
any reasonable assessment of current or
historical distribution, population size,
or trends. In addition, the petitioners do
not provide information, and we have
none available in our files, indicating
that the range or abundance of the
snowflies has been curtailed.
Although the petition provides an
inventory of various activities or
elements that may pose potential threats
to the straight snowfly or the Idaho
snowfly, as data on their current
population distribution, abundance, and
trend are completely lacking, and there
is no evidence that either species has
suffered any population decline or
reduction in range, the petitioners’
conclusion that both species ‘‘are in
imminent danger of extinction’’
(Petition, p. 5) appears to be purely
speculative. We have limited or no data
on the actual exposure of the straight
snowfly or Idaho snowfly to the
purported threats, or whether that
exposure, should it occur, would cause
a negative population response, let
alone result in the present or threatened
endangerment of the species. All
available threat information presented is
generalized in nature, and both the
NatureServe accounts and the IDFG
Comprehensive Wildlife Conservation
Strategy concede that ‘‘specific threats
to Idaho populations have not been
identified’’ (IDFG 2005, pp. 592–584;
NatureServe 2010a, p. 2; NatureServe
2010b, p. 1). While we may agree with
the petition’s description of impaired
aquatic habitat conditions within the
range of these two species, we simply
have no information to link the effect of
these conditions with the snowfly
populations. Therefore the petition
lacks substantial information to indicate
the threats listed in the petition are
significantly impacting the straight
snowfly or Idaho snowfly or threatening
their continued existence. Based on the
information presented in the petition
and available in our files, we have no
evidence to suggest that threats may be
acting on either the straight snowfly or
the Idaho snowfly such that either
species may currently be in danger of
extinction or likely to become so within
the foreseeable future. Therefore, we
conclude that a reasonable person
would not believe that the measure
proposed in the petition may be
warranted.
On the basis of our determination
under section 4(b)(3)(A) of the Act, we
find the petition does not present
substantial scientific or commercial
information to indicate that listing
either the straight snowfly or Idaho
snowfly as endangered or threatened
under the Act is warranted at this time.
Although we will not review the status
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of these species at this time, we
encourage interested parties to continue
to gather data that will assist with the
conservation of the straight snowfly and
Idaho snowfly. If you wish to provide
information regarding the straight
snowfly or Idaho snowfly you may
submit your information or materials to
the State Supervisor, Idaho Fish and
Wildlife Office (see ADDRESSES), at any
time.
References Cited
A complete list of references cited is
available on the Internet at https://
www.regulations.gov and upon request
from the Idaho Fish and Wildlife Office
(see ADDRESSES).
Authors
The primary authors of this notice are
the staff members of the Idaho Fish and
Wildlife Office (see ADDRESSES).
Authority
The authority for this action is section
4 of the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et
seq.).
Dated: July 21, 2011.
Gregory E. Siekaniec,
Acting Director, U.S. Fish and Wildlife
Service.
[FR Doc. 2011–19445 Filed 8–1–11; 8:45 am]
BILLING CODE 4310–55–P
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS–R2–ES–2011–0047; MO
92210–0–0008–B2]
Endangered and Threatened Wildlife
and Plants; 12-Month Finding on a
Petition To List the Redrock Stonefly
as Endangered or Threatened
Fish and Wildlife Service,
Interior.
ACTION: Notice of 12-month petition
finding.
AGENCY:
We, the U.S. Fish and
Wildlife Service (Service), announce a
12-month finding on a petition to list
the Redrock stonefly (Anacroneuria
wipukupa) as endangered or threatened
and to designate critical habitat under
the Endangered Species Act of 1973, as
amended. After review of all available
scientific and commercial information,
we find that listing the Redrock stonefly
is not warranted at this time. However,
we ask the public to submit to us any
new information that becomes available
SUMMARY:
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concerning the threats to the Redrock
stonefly or its habitat at any time.
DATES: The finding announced in this
document was made on August 2, 2011.
ADDRESSES: This finding is available on
the Internet at https://
www.regulations.gov at Docket Number
FWS–R2–ES–2011–0047. Supporting
documentation we used in preparing
this finding is available for public
inspection, by appointment, during
normal business hours at the U.S. Fish
and Wildlife Service, Arizona Ecological
Services Office, 2321 West Royal Palm
Road, Suite 103, Phoenix, AZ 85021.
Please submit any new information,
materials, comments, or questions
concerning this finding to the above
street address.
FOR FURTHER INFORMATION CONTACT:
Steve Spangle, Field Supervisor,
Arizona Ecological Services Office (see
ADDRESSES); by telephone at 602–242–
0210; or by facsimile at 602–242–2534.
If you use a telecommunications device
for the deaf (TDD), please call the
Federal Information Relay Service
(FIRS) at 800–877–8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Endangered
Species Act of 1973, as amended (Act)
(16 U.S.C. 1531 et seq.), requires that,
for any petition to revise the Federal
Lists of Threatened and Endangered
Wildlife and Plants that contains
substantial scientific or commercial
information that listing the species may
be warranted, we make a finding within
12 months of the date of receipt of the
petition. In this finding, we will
determine that the petitioned action is:
(1) Not warranted, (2) warranted, or (3)
warranted, but the immediate proposal
of a regulation implementing the
petitioned action is precluded by other
pending proposals to determine whether
species are endangered or threatened,
and expeditious progress is being made
to add or remove qualified species from
the Federal Lists of Endangered and
Threatened Wildlife and Plants. Section
4(b)(3)(C) of the Act requires that we
treat a petition for which the requested
action is found to be warranted but
precluded as though resubmitted on the
date of such finding, that is, requiring a
subsequent finding to be made within
12 months. We must publish these 12month findings in the Federal Register.
Previous Federal Actions
On June 25, 2007, we received a
formal petition dated June 18, 2007,
from WildEarth Guardians requesting
that we list the Redrock stonefly as
either endangered or threatened and
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that critical habitat be designated under
the Act. This species was part of a
petition to list 475 species in the
southwestern United States. WildEarth
Guardians incorporated all analyses,
references, and documentation provided
by NatureServe in its online database at
https://www.natureserve.org into the
petition. This included information
produced by the Natural Heritage
Network, particularly the Heritage Data
Management System compiled by the
Arizona Game and Fish Department
(AGFD) (AGFD 2004, pp. 1–3).
Relative to the Redrock stonefly, the
petition provided information on the
species’ current distribution, indicating
it was limited to Oak Creek, Yavapai
County, Arizona. The remaining
information was general in nature
describing factors that influence the
entire stonefly order. The petition
clearly identified itself as a petition and
included the identification information
required at 50 CFR 424.14(a). We sent a
letter to the petitioners dated July 11,
2007, acknowledging receipt of the
petition and stating that the petition was
under review. The 90-day finding was
published in the Federal Register on
December 16, 2009 (74 FR 66866). This
notice constitutes the 12-month finding
on the June 18, 2007, petition to list the
Redrock stonefly as endangered or
threatened.
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Species Information
Taxonomy and Species Description
The Redrock stonefly is an aquatic
insect in the Family Perlidae and the
Order Plecoptera. Immature stoneflies,
or nymphs, are aquatic and generally
live in cold-water streams. The nymphs
have external gills, which may be
present on almost any part of the body.
Nymphs appear very similar to adults
but lack wings (Stewart and Harper
1996, p. 218). Most stonefly nymphs are
herbivorous, feeding on submerged
leaves and algae, but other stonefly
species are predaceous and feed on
other aquatic macroinvertebrates
(Stewart and Harper 1996, p. 217).
Stoneflies remain in nymph form for 1
to 3 years, depending on species, before
emerging and becoming terrestrial
adults (Bouchard 2004, p. 77). Adult
stoneflies generally only survive for a
few weeks, and emerge only during
specific times of the year. Some adult
stoneflies do not feed at all, but those
that do are herbivorous.
The family Perlidae includes
relatively large, predaceous stoneflies.
They have external gills found on three
thoracic (middle body) segments
(Bouchard 2004, p. 85). The
Anacroneuria genus is the largest genus
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in the Perlidae family, primarily
occurring in the Neotropical regions of
Central and South America (Jewitt 1958,
p. 159; Bispo and Froehlich 2004, p.
191). There are 231 described and 19
undescribed species within this genus
occurring from the southernmost United
States to South America (DeWalt et al.
2010, p. 1). The genus Anacroneuria
expanded northward into Central
America, Texas, and Arizona about 4
million years ago after the formation of
the Isthmus of Panama, during the
Pliocene Period (Fochetti and Tierno de
Figueroa 2008, p. 374).
Anacroneuria was confirmed to exist
in the United States when Redrock
stonefly was described from Yavapai
County, Arizona (Baumann and Olson
1984, pp. 489–492). Anacroneuria
nymphs (immature stages) were first
collected in Oak Creek at Page Springs
in 1975, and the first adults were
collected from Oak Creek at Redrock
Crossing in 1978 (Baumann and Olson
1984, p. 489).
The Redrock stonefly is a largewinged stonefly. Adult male body
lengths range between 0.4 to 0.5 inches
(in) (10 to 12 millimeters (mm)), and
female body lengths are 0.6 in (15 mm).
Overall coloration is the same between
genders: yellow head, brown and yellow
body with bands bordering the midline.
Redrock stonefly legs are covered with
small brown spines on the upper
surface, and the abdomen has many
small spinules on the edges (Baumann
and Olson 1984, pp. 489–492). Stewart
and Harper (1996, pp. 231, 255, 258)
provide morphological characters to
separate Anacroneuria adults and
nymphs from other Perlidae genera.
Anacroneuria adults and nymphs are
distinguished from all other
southwestern Perlidae for having two
ocelli (simple eyes) on top of their head
rather than three. The only other
western Perlidae genus with two ocelli
is Neoperla, but it is not found in
Arizona (Stewart and Stark 2002, p.
350).
Ecology
Baumann and Olson (1984, pp. 489–
492) is the only published paper
describing the Redrock stonefly. This
paper does not provide any specific
habitat or ecology information on this
species. However, the following
ecological information is available from
published reports on other
Anacroneuria species. We presume that
the information generally applies to
Redrock stonefly.
At early ages and small sizes,
Anacroneuria nymphs are primarily
detrivorous, meaning they feed on
decayed leaves, algae, and other organic
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matter. Older larger nymphs are
predaceous, feeding entirely on other
aquatic insects including Dipteran (true
fly) larvae and Ephemeropteran (mayfly)
nymphs, and other smaller stonefly
nymphs. North American Perlidae
stonefly nymphs, in addition to foraging
in riffle (shallow, flowing water)
habitats, often forage within leaf packs
(Femenella and Stewart 1986, pp. 535–
536). Neotropical Anacroneuria nymphs
forage in leaf litter as predators (Baptista
et al. 2001, p. 251; Wantzen and Wagner
2006, p. 220); we assume that leaf litter
provides an important foraging habitat
for Redrock stonefly nymphs. Leaf litter
availability varies in southwestern U.S.
streams (Schade and Fisher 1997, p.
612). Leaf litter can accumulate behind
large rocks, behind logs, along the
stream margins where the current is
slower, and behind other obstructions in
high-gradient streams (Hoover et al.
2006, pp. 443–444). Intense local
thunderstorms generate severe flash
floods, which may reduce leaf litter
availability for that season (Schade and
Fisher 1997, pp. 612, 624). Predaceous
stoneflies, including the Redrock
stonefly, must then be able to forage in
riffle areas outside of leaf litter when it
is not available in their habitat. Adult
Anacroneuria do not eat; they
apparently rely on the predaceous diet
of their late nymphal stages for
reproductive organ and egg
development (Fenoglio 2003, pp. 2, 16).
Neotropical Anacroneuria have a
multivoltine life cycle (more than one
life cycle, from egg to adult, occurs
during a year) (Jackson and Sweeney
1995, p. 122). Because multivoltine life
cycles are unknown in stoneflies from
temperate climates (United States and
Canada) (Brittain 1990, p. 4), we
anticipate that the Redrock stonefly
would have a univoltine life cycle (only
one life cycle from egg to adult per
year).
Stoneflies use egg or nymphal
diapause (a period of suspended growth
or development) during harsh summer
conditions to allow them to survive
seasonally poor water conditions and
low stream flows (Snellen and Stewart
1979, p. 663; Brittain 1990, p. 8; Favret
and DeWalt 2002, p. 37). During
summer diapause, stonefly eggs or
nymphs suspend development and
remain buried in the moist stream
bottom sediment until optimal growth
conditions return. Stoneflies, including
Perlidae, also use this summer diapause
to survive in intermittent streams
(streams that only flow as a response to
snowmelt or rain storm runoff and have
insufficient groundwater contribution to
provide surface flow during the
summer) (Snellen and Stewart 1979, p.
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1; Feminella 1996, p. 659; Miller and
Golladay 1996, p. 685). The Redrock
stonefly may be expected to use
diapauses during dry periods when
water conditions and quantity are low.
Aquatic macroinvertebrates drift, or
move downstream in their habitats,
under different circumstances.
Catastrophic drift occurs when large
flood events carry macroinvertebrates
downstream (Brittain and Eikland 1988,
pp. 82–83). All aquatic
macroinvertebrates are likely to
experience this drift event if they are
unable to find suitable protection during
a flood event. This may also include
drift from substrate disturbance from
other means such as hikers, livestock, or
vehicles moving across the stream.
Aquatic macroinvertebrates may
behaviorally drift to colonize new
habitats to reduce competition for food
and space (Brittain and Eikland 1988, p.
84). Predator-induced drift may occur
when they are disturbed by a foraging
predator and escape by allowing the
water current to carry them away
(Malmqvist and Sjostrom 1987, p. 402).
Intentional drifting, as in behaviorally
or predator-induced cases, is only
practiced by those macroinvertebrates
that are capable swimmers (such as
Baetid and Amelitid mayflies) and can
control when, where, and how far they
drift (Malmqvist and Sjostrom 1987, p.
402). Drifting insects are very
susceptible to fish predation; they are
out in the open water column where
they are easily seen. Intentional drift
often occurs at night to avoid fish
predation (Flecker 1992, p. 438).
Aquatic macroinvertebrates that are
poor swimmers, such as predaceous
stoneflies, are less likely to purposely
drift because they would be susceptible
to fish predation (Radar and McArthur
1995, p. 8). However, in some cases,
predaceous stoneflies may drift when
suitable foraging sites are separated by
areas, such as sand-bottom streams,
with little hiding cover to crawl across.
Large crawling stoneflies, like the
Redrock stonefly, are also susceptible to
fish predation where there is little
cover. In contrast, areas of continuous
cover, such as cobble-bed streams,
provide protection from fish predation
when stoneflies move from one area to
another (Radar and McArthur 1995, p.
1). The known Redrock stonefly sites are
continuous cobble-bedded streams,
which reduces the need to drift to new
areas.
Distribution
The Redrock stonefly is known to
only occur in Arizona, and it was
initially described from specimens
collected at two sites: Redrock Crossing
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at Red Rock State Park and Page Springs
on Oak Creek, Yavapai County, Arizona
(Baumann and Olson 1984, p. 492;
AGFD 2004, p. 1). Additional stonefly
surveys were conducted to determine
the Redrock stonefly’s current status
and distribution (Service 2010a, p. 1).
During surveys in May and June 2010,
adult Redrock stoneflies were found at
the Page Spring Fish Hatchery on Oak
Creek and Wet Beaver Creek, and near
an Arizona Department of
Environmental Quality (ADEQ) Bear
Flats sampling site on Tonto Creek
(Service 2010, p. 1). Surveys on West
Clear Creek, east of Camp Verde in
Yavapai County, did not identify any
Redrock stoneflies. Identification of
adult specimens was confirmed by
stonefly experts (Kondratieff pers.
comm. 2010, p. 1; Baumann pers.
comm. 2010, p. 1; Stark pers. comm.
2010, p. 1).
The ADEQ had previously collected
Anacroneuria nymphs during water
quality monitoring on Campbell Blue
Creek in Apache County in 2000; four
sites on Upper Tonto Creek in Gila
County from 1995 to 2008; Spring Creek
in Gila County in 1998; and Wet Beaver
Creek (upstream of the Service’s survey
location) in 1995 (Spindler 2010a, p. 1).
Species identification was not possible
because only Anacroneuria nymphs
were collected. However, because there
are no other stonefly species in that
genus known from Arizona, we presume
these nymphs represent collections of
Redrock stonefly.
In total, we now believe the Redrock
stonefly occupies at least 10 sites within
five different streams in central Arizona.
As a result the only known change in
distribution of the species is the
increase from 2 sites, from which it was
initially described, to 10 sites where
additional surveys found it. The
increased range is a result of increased
survey efforts. We suspect that if
additional survey efforts were employed
for this species, its known range and
number of occurrences would likely
expand as well. This is because the
adult flying form of the Redrock stonefly
has the ability to easily disperse into
available habitats, and there are
numerous other habitats in this region
of Arizona that would appear suitable to
support Redrock stoneflies. The species
does not appear to be a habitat
specialist, and so we would expect to
find it in other similar stream habitats
if more survey efforts were undertaken.
The current sites where the Redrock
stonefly occurs span about 180 miles
(mi) (288 kilometers (km)) east to west
across the Central Highlands
Physiographic Region in Arizona and
include the Verde and Salt Rivers and
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Tonto Creek headwaters. Because of the
high elevations and associated higher
rainfall and snowfall, these watersheds
contain the highest concentration of
perennial streams (water present
throughout the year) in Arizona
(Arizona Department of Water
Resources (ADWR) 2009a, p. 4). The
Redrock stonefly may also occupy other
un-surveyed water bodies (for example,
East Verde River, Dude and Canyon
Creeks, and numerous sites on the
White Mountain Apache Indian
Reservation) located in this
physiographic region. The Redrock
stonefly sites or their watersheds are
found on the Coconino, Tonto, and
Apache-Sitgreaves National Forests.
Descriptions of occupied areas on each
National Forest are provided below.
To date, the Redrock stonefly has
been found only in perennial streams.
All sites are in moderate gradient
(approximately 2 percent slope), cobblebedded streams, with overhanging
streambank vegetation including willow
(Salix sp.), velvet ash (Fraxinus
velutina), Arizona alder (Alnus
oblongifolia), and blackberry (Rubus sp.)
(Service 2010a, p. 1).
There is substantial variation in the
stream size, elevation, and water
temperature in areas occupied by the
Redrock stonefly, making this species
more of a generalist than most other
stonefly species (Brittain 1990, p. 2).
Stream sizes range from Campbell Blue
Creek (47 square-mi (122 square-km)
watershed and 160 cubic-feet-persecond (cfs) (4.5 cubic-meters-persecond (cms)) bankfull channel
discharge) to Oak Creek at Page Springs
(355 square-mi (919 square-km)
watershed and 1,400 cfs (39.6 cms)
bankfull channel discharge). Bankfull
channel discharge relates to the relative
frequent flow (occurs 2 out of every 3
years) that fills the river channel to the
point of inundating the floodplain
(Rosgen 1996, p. 2–2). Elevations at
Redrock stonefly sites range from 3,460
feet (ft) (1,055 meters (m)) on Oak Creek
below Page Springs to 6,670 ft (2,033 m)
on Campbell Blue Creek. Adjacent
upland vegetation ranges from mixed
paloverde and cactus desert (Oak Creek
at Page Springs) to ponderosa pine
(Pinus ponderosa) and mixed conifer
(Campbell Blue Creek). The majority of
sites are located between 3,900 and
5,100 ft (1,190 and 1,555 m) in
elevation. Seven of the 10 Redrock
stonefly sites are considered warmwater streams (streams located below
5,000 ft (1,524 m) elevation): Oak Creek
(two sites), Wet Beaver Creek (two sites),
Spring Creek, and the two lower Tonto
Creek sites (Spindler 2010c, p. 1). The
remaining three sites (streams above
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5,000 ft (1,524 m)), Campbell Blue Creek
and the two higher Tonto Creek sites,
are considered cold-water streams.
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Coconino National Forest
Oak Creek is a perennial stream in
Coconino and Yavapai Counties in
central Arizona. Average annual
precipitation in Oak Creek Canyon is 28
in (71 cm) (ADWR 2009a, p. 247). Its
two main tributaries are the West Fork
of Oak Creek and Pumphouse Wash on
the Coconino National Forest. Oak
Creek base flow is maintained by
springs at Indian Gardens, by Page
Springs, and from its Spring Creek
tributary. Oak Creek, upstream and
downstream of the Redrock stonefly
sites, flows through Coconino National
Forest, private lands, and State-owned
lands. Redrock Crossing, the farthest
upstream Redrock stonefly site in
Redrock State Park, is located
approximately 4.7 river miles (7.6 km)
downstream from the city of Sedona.
The Page Spring site, at the Page Springs
Fish Hatchery which is owned and
operated by the AGFD, is approximately
18.7 river miles (30 km) downstream of
Sedona.
Wet Beaver Creek is located east of
Interstate Highway 17 and north of the
city of Camp Verde in Yavapai County,
Arizona. It is a tributary to Beaver
Creek, which eventually flows into the
Verde River at Camp Verde. The
Redrock stonefly was collected at two
sites on Wet Beaver Creek. The ADEQ
collected nymphs upstream of the U.S.
Geological Survey (USGS) stream gage
and adults were also collected at the
Beaver Creek Ranch (Service 10a, p. 1).
Both sites are located on the National
Forest; the downstream site is adjacent
to private land.
Tonto National Forest
Tonto Creek originates on the edge of
the Mogollon Rim at about 7,600 ft
(2,300 m) in elevation in mixed conifer
forest, dominated by ponderosa pine.
Average annual precipitation for the
Upper Tonto Creek watershed ranges
from 22 to 30 in (56 to 76 cm) (ADWR
2009a, p. 173). There are 10 different
springs that produce more than 10
gallons per minute (gpm) (38 liters per
minute (lpm)) that contribute to Tonto
Creek (ADWR 2009a, p. 182). Tonto
Spring at the headwaters of Tonto Creek
is the largest spring in the Tonto Creek
Basin with a measured discharge of
1,291 gpm (4,887 lpm) (ADWR 2009a, p.
180).
The ADEQ collected Redrock stonefly
nymphs at four sites on Tonto Creek:
above Bear Flats; below the Christopher
Creek confluence; below the Haigler
Creek confluence; and below Bear Flats,
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Apache-Sitgreaves National Forests
Campbell Blue Creek originates
southwest of Alpine, Apache County, in
eastern Arizona, and flows southeasterly
for 17 river miles (27 km) to its
confluence with Dry Blue Creek in New
Mexico. Perennial flow initiates
downstream of the Coleman Creek/
Campbell Blue Creek confluence.
Campbell Blue Creek has one spring that
produces at least 10 gpm (38 L pm),
located downstream of the Redrock
stonefly site (ADWR 2009b, pp. 351–
352). All of the tributaries that drain
into Campbell Blue Creek are
intermittent (ADWR 2009b, p. 352). The
area receives an average of 21 inches (53
cm) of precipitation per year (ADWR
2009b, p. 342).
Lists of Endangered and Threatened
Wildlife and Plants. Under section
4(a)(1) of the Act, a species may be
determined to be endangered (in danger
of extinction throughout all or a
significant portion of its range) or
threatened (likely to become an
endangered species within the
foreseeable future throughout all or a
significant portion of it range) based on
any of the following five factors:
(A) The present or threatened
destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial,
recreational, scientific, or educational
purposes;
(C) Disease or predation;
(D) The inadequacy of existing
regulatory mechanisms; or
(E) Other natural or manmade factors
affecting its continued existence.
In making this finding, information
pertaining to the Redrock stonefly in
relation to the five factors provided in
section 4(a)(1) of the Act is discussed
below. In making our 12-month finding,
we considered and evaluated the best
available scientific and commercial
information.
In considering what factors might
constitute threats, we must look beyond
the mere exposure of the species to the
factor to determine whether the species
responds to the factor in a way that
causes actual impacts to the species. If
there is exposure to a factor, but no
response, or only a positive response,
that factor is not a threat. If there is
exposure and the species responds
negatively, the factor may be a threat
and we then attempt to determine how
significant a threat it is. If the threat is
significant, it may drive or contribute to
the risk of extinction of the species such
that the species warrants listing as
endangered or threatened as those terms
are defined by the Act. This does not
necessarily require empirical proof of a
threat. The combination of exposure and
some corroborating evidence of how the
species is likely impacted could suffice.
The mere identification of factors that
could impact a species negatively is not
sufficient to compel a finding that
listing is appropriate; we require
evidence that these factors are operative
threats that act on the species to the
point that the species meets the
definition of endangered or threatened
under the Act.
Summary of Factors Affecting the
Redrock Stonefly
Section 4 of the Act and its
implementing regulations (50 CFR 424)
set forth procedures for adding species
to, removing species from, or
reclassifying species on the Federal
A. The Present or Threatened,
Destruction, Modification, or
Curtailment of the Species’ Habitat or
Range
Under Factor A, we will discuss a
variety of potential impacts to Redrock
stonefly habitat including: (1) Water
south of Kohls Ranch (Spindler 2010a,
p. 1). Two adult female Redrock
stoneflies were also collected at the Bear
Flats Campground in June 2010. All
Redrock stonefly sites on Tonto Creek
are on the Tonto National Forest. This
portion of Tonto Creek is predominantly
U.S. Forest Service land, with the
exception of a private development at
Bear Flats and Kohl’s Ranch. The
Redrock stonefly sites downstream of
Bear Flats and downstream of the
Haigler Creek confluence are located
within the Hells Gate Wilderness and
managed by the U.S. Forest Service.
Spring Creek is located on the Tonto
National Forest near the town of Young,
Gila County, Arizona. The Redrock
stonefly site on Spring Creek is
downstream of the Brady Canyon
confluence and has an 88 square-mi
(228 square-km) watershed. Spring
Creek eventually flows 11 mi (17.6 km)
from this site into Tonto Creek. Annual
precipitation averages 24 in (61 cm)
(ADWR 2009b, p. 173). Spring Creek is
an interrupted flow system with
perennial water disappearing in wider
alluvial valleys (gently sloping areas
with deep sediment deposits) then
resurfacing in narrow canyons. It is
mapped as an intermittent stream below
its confluence with Walnut Creek
(ADWR 2009a, p. 182, Figure 5.3–6).
There are no springs along Spring Creek
or located within its watershed that
produce stream flows greater than 1
gpm (3.8 lpm) (ADWR 2009b, p. 182).
ADWR (2009, p. 187) does not record
any wells located within the Spring
Creek watershed.
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quality, (2) livestock grazing, (3)
crayfish, (4) wildfires, (5) prescribed
fires, (6) recreation, and (7) urban and
rural development. The potential
impacts of nonnative crayfish are
discussed here related to habitat
alterations, and other impacts from
crayfish are discussed under Factor C
below.
Water Quality
Impacts to aquatic habitats, especially
from pollution, have been identified as
a concern for the Redrock stonefly
(AGFD 2004, p. 2). Most stonefly species
are restricted to cold-water
environments because their small
external gills require water with high
dissolved oxygen levels (Surdick and
Gaufin 1978, p. 3; Covich 1988, p. 365;
Brittain 1990, p. 2). In unpolluted, coldwater streams and rivers, dissolved
oxygen concentrations usually remain
high, well above 80 percent saturation,
because oxygen solubility (ability to be
absorbed in water) increases as
temperature decreases (Hauer and Hill
1996, p. 96). High organic nutrient
levels can also be detrimental because
they cause excessive microbial
(microscopic organisms) growth. These
organisms consume oxygen from the
water (Hauer and Hill 1996, pp. 96–97).
Organic pollution can also cause
excessive algae growth, which can
decrease dissolved oxygen when the
algae respires or absorbs oxygen at night
(Hauer and Hill 1996, p. 97) or when the
vegetation dies and decomposes (Jewell
1971, p. 1457). Because Plecoptera are
considered sensitive to low dissolved
oxygen levels in water, their presence is
often used for monitoring water quality
(Surdick and Gaufin 1978, p. 1; Udo et
al. 1984, p. 189). However, stoneflies in
the genus Anacroneuria are an
exception to this standard practice,
because species in this genus are wellestablished in warm-water neotropic
regions of Central and South America
and can withstand lower dissolved
oxygen levels (Stark and Kondratieff
2004, p. 1; Fenoglio 2007, p. 220;
Nelson 2008, p. 184; Springer 2008, p.
274). Anacroneuria are often found in
streams with warm-water temperatures
ranging from 75 to 78 degrees
Fahrenheit (24 to 26 degrees Celsius)
(Froehlich and Oliveira 1997, p. 1882;
Fenoglio and Rosciszewska 2003, p.
163), which limits available dissolved
oxygen. Anacroneuria are adapted to
low dissolved oxygen levels by having
egg capsules with tiny, thin canals
oriented perpendicularly to the surface
of the shell that enhance oxygen uptake
compared to other stoneflies (Fenoglio
and Rosciszewska 2003, p. 163). As a
result of these adaptations, the Redrock
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stonefly may be tolerant of impaired
water quality, particularly elevated
water temperature and excessive
nutrients that can lead to low dissolved
oxygen.
Several researchers have reported that
Anacroneuria are tolerant of poor water
quality conditions. In fact, due to its
tolerance for low dissolved oxygen and
poor water quality, Tomanova and
Tedesco (2007, p. 69) determined that
Anacroneuria may not be a good
indicator of water quality. Baptista et al.
(2007, p. 92) noted that in tropical
streams, Anacroneuria was an exception
to the rule that Plecoptera are
considered sensitive to environmental
degradation. In addition, Anacroneuria
were documented in numerous
bioassessment reviews and studies in
South America in waters with high
organic (nutrients) levels, although less
so than in unpolluted waters (Froelich
and Oliveria 1997, p. 183; Bispo et al.
2002, p. 413; Bispo and Oliveria 2007,
p. 287). Bobot and Hamada (2002, p.
300) found that Anacroneuria densities
did not respond to suspended sediment
caused by deforestation in streams in
central Brazil. In another study,
Anacroneuria were the only stoneflies
found in streams under strong
anthropogenic (human-caused)
influences (Bispo et al. 2002, p. 413).
We presume that the Redrock stonefly is
similar to other species of stoneflies in
the Anacroneuria genus and would,
therefore, be tolerant of poor quality
conditions, should these types of
conditions be present in their habitat.
The ADEQ is required by the Clean
Water Act (33 U.S.C. 1251 et seq.) to
conduct a comprehensive analysis of
water quality data associated with
Arizona’s surface waters to determine
whether State water quality standards
are being met and designated uses (such
as human contact, aquatic, and wildlife)
are being supported. Since 1992, the
ADEQ has evaluated water quality at
eight sites currently known to be
occupied by Redrock stonefly nymphs
(Spindler 2010b, p. 1). The ADEQ rated
five of the eight sites, Oak Creek (two
sites) and Tonto Creek (three sites), as
having impaired water quality as a
result of Escherichia coli (E. coli)
bacteria level exceedance in 2006 and
2008 (Avila et al. 2009, pp. VR–33, VR–
35, SR–64, SR–65). The ADEQ notes
that high E.coli levels, on their own, do
not affect aquatic invertebrates
(Spindler 2010b, p. 1), and we do not
expect them to affect Redrock stoneflies.
This parameter is measured for safety
thresholds for the human contact
designated use (Marsh 2009, p. G–22).
The ADEQ found no other water quality
concerns during these surveys. Our
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review found no other information
indicating water quality concerns in the
streams where Redrock stoneflies are
known to occur.
Based on the results of ADEQ water
quality analyses and the Redrock
stonefly’s wide range of habitats and
presumed tolerance to higher levels of
sedimentation and nutrient enrichment,
we conclude that water quality
conditions in Arizona are not a
significant threat to the Redrock stonefly
or its habitat.
Livestock Grazing
If livestock grazing is not wellmanaged, aquatic insects can be
negatively impacted by decreased
riparian vegetation, stream bank
destabilization, and increases in
sedimentation and water temperature
(Braccia and Voshell 2006, p. 269;
McIver and McInnis 2007, p. 294).
Improper grazing use levels may lead to
soil erosion from riparian and upland
vegetation removal, soil litter removal,
increased soil compaction from
trampling, and increased bare ground
(Kauffman and Krueger 1984, p. 434;
Schulz and Leininger 1990, pp. 297–
298; Belsky et al. 1999, p. 30). Excessive
livestock grazing in upland watersheds
can also lead to bare, compacted soils,
which in turn allow less water
infiltration, which generates increased
rates of surface runoff and can
contribute to soil erosion as well as
flooding and stream bank alterations
(Abdel-Magid et al. 1987, pp. 304–305;
Orodho et al. 1990, pp. 9–11). Increased
soil erosion leads to higher sediment
loads in nearby waters, which can
degrade instream and riparian habitat
and increase water turbidity. Perlidae
stoneflies, like Redrock stoneflies, may
experience reduced respiratory ability
when their gills are covered by sediment
(Lemly 1982, pp. 238–239). Sediment
that becomes embedded in the
interstitial spaces around large substrate
can smother insect (such as stonefly)
eggs and larvae, reduce forage for the
nymphal stage, and limit suitable egg
depositing sites (Brusven and Prather
1974, p. 31; Waters 1995, pp. 65–66).
The ADEQ (Spindler 2010c, p. 1)
classified the Redrock stonefly sites as
moderate gradient based on riffledominated cobble or gravel or both
substrate streams (Rosgen Stream
Classification B3 channel types) (Rosgen
1994, p. 174; Rosgen 1996, pp. 5–68, 5–
72). The B3 stream types are moderately
entrenched systems with channel
gradients of 2 to 4 percent. The channel
bottom materials are composed
primarily of cobble (2.5 to 10 in (64 to
256 mm) intermediate axis diameter)
with a few boulders and lesser amounts
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of sands and gravels. Rosgen (1994, p.
194) determined that B3 stream types
have low sensitivity to disturbance and
low streambank erosion potential. The
large cobble substrate that is resistant to
movement during frequent flood events
is also resilient to livestock disturbance.
Given the energy required to initiate
movement of large cobbles, these stream
channel types do not rely on vegetation
for stability; the substrate size in itself
provides stabilization.
Recent ADEQ water quality data do
not show that livestock are having a
negative impact on water condition at
any of the Redrock stonefly sites, in the
form of excess sediment or nutrients
that are contributing to impairment
(Avila et al. 2009, pp. SR–64, SR–65,
VR–33, VR–35, VR–61, VR–62). The
ADEQ sites that are impaired and the
causes of impairment are discussed
above in the Water Quality section.
One reason that grazing is not
affecting streams that provide habitat for
the Redrock stonefly is that many of the
streams are in areas with well-managed
grazing or no grazing. In Coconino
National Forest, the Oak Creek sites are
not on livestock grazing allotments.
Almost the entire Oak Creek corridor is
excluded from livestock grazing. The
Wet Beaver Creek stonefly sites are also
excluded from livestock grazing. In the
Apache–Sitgreaves National Forest,
Campbell Blue Creek is also excluded
from livestock grazing within the
downstream segment where Redrock
stoneflies were collected by ADEQ
(USDA 2009, p. 87).
In the Tonto National Forest, the five
Upper Tonto Creek sites are located on
two livestock grazing allotments:
Christopher Mountain/Ellinwood and
Diamond Butte. The Redrock stonefly
sites in the Christopher and Tonto
Creeks are excluded from grazing due to
their topography (they are in very steep
terrain), or they are located in pastures
that are not grazed. The Spring Creek
site is not located on a grazing
allotment, but is used for the HeberReno Sheep Driveway on the Tonto and
Apache-Sitgreaves National Forests.
Two permitted livestock operators are
authorized to use the driveway as part
of their 10-year grazing permits. The
permitted sheep herding is currently
managed through Annual Operating
Instructions that are prepared for the
Long Tom and Beehive/Sheep Springs
allotments in coordination with the
livestock operators and six ranger
districts on the two forests. The Sheep
Driveway is used to access summer
grazing allotments on the ApacheSitgreaves National Forest from winter
grazing lands located on private
property in Phoenix, Arizona.
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Approximately 8,000 permitted sheep,
plus 7 pack animals per band for the
sheep herders and camp tender, are
authorized on the Sheep Driveway
(USDA 2010a, pp. 1–2). Sheep are kept
out of all riparian areas except when
crossing and watering (USDA 2010a, p.
11). All riparian areas are excluded from
use as bedding grounds. The limited
sheep grazing at established stream
channel crossings does not likely affect
the Redrock stonefly. These stream
crossing sites have little to no riparian
vegetation and no potential to produce
riparian vegetation because they are dry
washes or road surfaces, or they consist
of large cobble and boulder substrate
(USDA 2010a, p. 3).
Livestock grazing is not threatening
the habitat of the Redrock stonefly,
because the habitat has limited exposure
to the effects of grazing. Livestock are
excluded from the Oak, Wet Beaver, and
Campbell Blue Creeks Redrock stonefly
sites due to decisions of land managers
or property owners. The Tonto Creek
Redrock stonefly sites are located in
areas difficult for livestock to access.
Only one area is used as a travel
corridor for moving sheep (Spring
Creek), and the stream crossing sites are
not likely to affect Redrock stoneflies.
Therefore, we find that grazing is not a
significant threat to the Redrock stonefly
or its habitat.
Crayfish
Crayfish are not native to Arizona.
The red swamp crayfish (Procambarus
clarkii) and the green or northern
crayfish (Orconectes virilis) were
introduced in Arizona in the 1970s
(Taylor et al. 1996, p. 27; Inman et al.
1998, p. 3). The red swamp crayfish is
not currently found in any of the
Redrock stonefly sites (Sorensen 2010,
p. 1; USGS 2010a, p. 1). The northern
crayfish, however, is found throughout
Arizona, including the following
Redrock stonefly sites: Tonto Creek
drainage; Oak Creek drainage (Holycross
et al. 2006, pp. 23, 40–44, 59); Verde
River drainage (Inman et al. 1998,
Appendix B; Holycross et al. 2006, pp.
14, 20–28, 54–56); Salt River drainage
(Inman et al. 1998, Appendix B;
Holycross et al. 2006, pp. 15, 29–44, 56–
60); and Spring Creek drainage and
Campbell Blue Creek drainage
(Holycross et al. 2006, pp. 25, 46, 55,
60).
Crayfish are known to affect aquatic
macroinvertebrate habitat in three ways:
(1) By increasing leaf litter
decomposition rates; (2) by feeding on
aquatic plants; and (3) by increasing
turbidity and sedimentation from
bioturbation when crayfish are
physically moving through fine
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substrates. The following discussion
addresses each of these three
mechanisms. Crayfish can also prey on
macroinvertebrates, and this is
discussed under Factor C.
First, crayfish may reduce the amount
of leaf litter in streams and reduce the
amount of forage and foraging habitat
available to Redrock stonefly nymphs.
The nymphs feed on detritus when
young; they then prey upon other
aquatic macroinvertebrates found in the
leaf litter (Fenoglio 2003, pp. 2, 16).
Forested streams receive a large portion
of their energy input from
allochthonous litter (mainly plant
material from terrestrial sources)
(Minshall 1967, p. 147; Vannote et al.
1980, p. 132; Wallace et al. 1997, p.
102). This litter, in the form of leaves
and wood, is an important food source
and foraging area for stream
invertebrates (Wallace and Webster
1996, p. 120; Usio 2000, p. 608).
Invertebrates that feed on leaf litter are
called shredders and consume course
particulate organic matter in the stream
channel. Shredders convert coarse
particulate organic matter into fine
particulate organic matter, which breaks
down litter and provides additional
food sources for stream
macroinvertebrates. In their native
range, crayfish serve an important
function by shredding coarse particulate
organic matter into fine matter in litterbased food webs (Usio 2000, p. 612;
Creed and Reed 2004, p. 225).
However, nonnative crayfish feeding
on leaf litter can significantly reduce the
time it would otherwise take to break
down leaf litter and may lower the
amount of foraging area available to
native macroinvertebrates (Usio 2000, p.
612; Creed and Reed 2004, p. 231;
Bobeldyk and Lamberti 2010, pp. 648,
652). Nonnative crayfish are typically
the largest invertebrate shredder in
streams (Usio 2000, p. 609; Parkyn et al.
2001, p. 641). Studies show that
reduced terrestrial litter amounts in
streams resulted in decreased
abundance of invertebrates (and their
predators) that feed on large and fine
particulate organic matter (Wallace et al.
1997, p. 102; Bobeldyk and Lamberti
2010, pp. 649, 652). Neotropical
Anacroneuria nymphs feed on the small
invertebrates that occur in association
with leaf litter and leaf packs
(accumulated piles of leaf litter)
(Benstead 1996, p. 371; Mathuriau and
Chauvet 2002, p. 390; Wantzen and
Wagner 2006, p. 220). Redrock stonefly
nymphs are expected to use leaf packs
as foraging habitat when leaf packs are
available and have not been removed
from the site by flooding (Schade and
Fisher 1997, p. 624). Redrock stonefly
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nymphs could have less available food
and foraging habitat as a result of
nonnative crayfish feeding on the leaf
litter and increasing the rate of leaf
breakdown. However, because leaf litter
availability is also affected by flood
events, the Redrock stonefly would be
expected to be adaptable and to satisfy
its foraging needs in other habitats such
as riffle areas. Therefore, the potential
loss of some leaf litter due to crayfish is
not expected to impact Redrock
stoneflies.
Second, crayfish may reduce the
amount of living aquatic vegetation in
streams. Crayfish feed heavily on living
aquatic plants (Chambers et al. 1990, p.
90; Creed 1994, p. 2098; Nystrom and
Strand 1996, pp. 678, 680). The
northern crayfish feeds on and reduces
aquatic vegetation available in streams,
removing food sources for herbaceous
invertebrates, which reduces
macroinvertebrate habitat, and may
cause a decrease in available prey items
as food for the Redrock stonefly. In one
example, Creed (1994, p. 2098) found
that a filamentous alga (Cladophora
glomerata), an aquatic plant commonly
fed upon by crayfish, was at least 10fold greater in aquatic habitats without
crayfish in Michigan streams.
Filamentous alga is an important
component of aquatic vegetation that
provides cover and food for
macroinvertebrates that predatory
stoneflies may feed on.
However, we believe that crayfish
feeding on aquatic plants is not likely to
impact the Redrock stonefly. This is
because Redrock stonefly nymphs occur
in moderately steep-gradient streams
with cobble substrates that do not
provide many areas with fine substrates
or low water velocities for herbaceous
vegetation to establish and persist. The
three factors that limit aquatic
vegetation growth in stream channels
are shade, large cobble substrate, and
high water velocity, and they are all
present at all Redrock stonefly sites
(Vannote et al. 1990, p. 132; Biggs 1996,
p. 135; Riis and Biggs 2003, pp. 1495–
1496; O’Hare et al. 2010, pp. 6–7;
Service 2010a, p. 1). We presume that
Redrock stoneflies, like most
Anacroneuria, feed in leaf litter and
gravel and cobble substrates rather than
in aquatic vegetation (Tamaris-Turizo
2007, p. 1). Therefore, crayfish
herbivory does not significantly impact
stonefly foraging habitat or prey
availability.
Third, crayfish can increase turbidity
(suspended sediment in the water
column) in wetlands and lakes as they
move and forage for prey in fine
sediments (Statzner et al. 2000, p. 1039;
Dorn and Wojdak 2004, p. 157). Many
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aquatic invertebrates depend upon open
interstitial spaces (small openings
between rocks) in channel substrate
(gravels and cobbles). Excessive
sediments in streams can fill the
interstitial spaces and reduce aquatic
invertebrate habitat (Waters 1995, pp.
65–68). Crayfish bioturbation (the
mobilizing of sediments by crayfish
activity) can impact lakes, ponds, and
wetlands, but it is not likely to
significantly affect high-gradient
streams, such as the sites where Redrock
stoneflies are present, because the small
amounts of suspended sediment would
be carried by stream flow through the
water column until they are deposited
downstream at lower gradient and lower
velocity sites.
In some situations, crayfish
bioturbation may actually improve
macroinvertebrate habitat in the stream
environment by removing fine
sediments from interstitial spaces. For
example, Statzner et al. (2000, p. 1039)
observed that crayfish bioturbation
removed fine sediments and benefited
gravel-spawning salmonids. Also, Creed
and Reed (2004, p. 234) found that
mayfly (Ephemeroptera) numbers
increased when crayfish bioturbation
removed fine sediments from gravel
streambeds in Maryland. This may be
particularly important for the recovery
of stream bottom habitats after silt
deposition following floods or other
upstream disturbances (Parkyn et al.
1997, p. 689). The Redrock stonefly sites
are stable stream channels that are
moderately steep and dominated by
cobbles. These sites usually have little
soft or fine sediments to be disturbed
and enter the water column. Therefore,
crayfish bioturbation is not likely to
impact Redrock stoneflies.
In summary, we considered three
mechanisms by which nonnative
crayfish could alter the habitat of the
Redrock stonefly: (1) Increasing leaf
litter decomposition rates; (2) feeding on
aquatic plants; and (3) increasing
turbidity and sedimentation from
bioturbation when crayfish are
physically moving through fine
substrates. Our analysis of the biology of
the stonefly and known ecology of the
crayfish finds that crayfish are not likely
a significant threat to the Redrock
stonefly or its habitat.
Wildfires
Wildfires, through alterations of the
terrestrial environment, can cause many
physical disturbances to streams
(Gresswell 1999, p. 194). Low-intensity
fire, which is cooler burning and does
not result in major changes in the
vegetation community in which it
occurs, has been a natural disturbance
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factor in forested landscapes for
centuries, and low-intensity fires were
common in Southwestern forests and
grasslands prior to European settlement
(Harrington and Sackett 1990, p. 122).
Fire suppression and wildfire control
during the past decades have changed
this natural fire regime, resulting in
unnatural fuel build-up by increased
understory vegetation and stand density
of large trees, which increases fire
severity (Harrington and Sackett 1990,
p. 122; Schoennagel et al. 2004, p. 661;
Westerling et al. 2006, p. 940). This
increased wildfire severity can result in
large increases in the magnitude and
frequency of floods resulting from
vegetation removal by fire that did not
likely occur prior to wildfire
suppression and control efforts (Neary
et al. 2003, p. 30). Moody and Martin
(2001, p. 2990) and Viera et al. (2004,
p. 1254) each noted increased soil
erodibility and reduced infiltration after
severe fires, which resulted in dramatic
increases in peak flow and sediment
load in streams draining burned
catchments. In Southwestern montane
watersheds, flood events may occur
during the July–August monsoon period
immediately following the May–June
fire season (Rinne 1996, p. 653).
Wildfires have occurred in the past
within watersheds that contain the
Redrock stonefly sites (for example, the
Picture Fire above Spring Creek, the
Brady Fire above Wet Beaver Creek, and
the Brins Fire and Division Fire above
Oak Creek). The Brady Fire burned
approximately 4,000 acres (ac) (1,620
hectares (ha)) in the upper Wet Beaver
Creek watershed in 2009 (U.S. Forest
Service 2010b, p. 1). Two USGS stream
gages are near the Oak Creek and Wet
Beaver Creek Redrock stonefly sites.
Wet Beaver Creek stream flow data do
not show that there has been a
significantly higher peak flow event
after the fire. The nearest Oak Creek
stream gage, immediately upstream of
Page Springs, began functioning in
October 1981. The Division Fire burned
approximately 650 ac (260 ha) on the
slopes above Oak Creek at Page Springs
in August 1980, and the Brins Fire
burned 4,317 ac (1,744 ha) north of
Sedona in June 2006 (U.S. Forest
Service 2010b, p. 1). The USGS stream
flow data do not show any significantly
higher peak flows after the two fires
(USGS 2010).
The direct effects of fire on stream
macroinvertebrate communities
generally are minor or indiscernible
(Rinne 1996, p. 655; Minshall et al.
1997, p. 2519; Minshall 2003, p. 155).
However, important exceptions may
include intense heating in areas of small
water volume (for example, small first-
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or second-order streams or shallow,
sluggish margins of larger streams) and
extended exposure to toxins from dense
smoke and errant retardant drops
(Minshall 2003, p. 156). Redrock
stoneflies may only experience limited
exposure to these effects in the swifter
flowing water they inhabit. Toxins and
heated water may be transported
through their habitat before cumulative
adverse effects result.
Instead, adverse effects of wildfire on
stream macroinvertebrates are largely
the result of physical changes in habitat
due to increased runoff after the fire
(Minshall et al. 1989, p. 712). This
higher runoff can scour, transport, and
redistribute sediments and organic
matter, and it can restructure the
physical stream environment (Herbst
and Cooper 2010, p. 1355). Aquatic
macroinvertebrates are somewhat
resilient to flood events. High numbers
may be removed after floods, but their
numbers quickly recover (Molles 1985,
p. 281; Hering et al. 2004, p. 454).
However, aquatic macroinvertebrates
showed low resistance and resilience to
the effects of repeated, large, post-fire
flood events (Viera et al. 2004, p. 1253).
Macroinvertebrate taxa richness and
densities in general were reduced after
the first large post-fire flood events, then
recovered until the next large flood
event (Viera et al. 2004, pp. 1247–1248).
In one example, a 3-year study from
central Arizona, Rinne (1996, p. 655)
found large flood events reduced
macroinvertebrate densities by 85 to 90
percent after the Dude Fire.
Primary consumers, organisms that
feed on plants, such as blackfly and
midge larvae (Diptera), and Baetid
mayflies, quickly recolonized and
dominated the community after wildfire
(Minshall et al. 1997, p. 2523; Viera et
al. 2004, p. 1255). Many of these
primary consumers are filter feeders,
which are able to take advantage of
increased organic matter entering the
stream after a fire (Minshall et al. 1989,
p. 713; Herbst and Cooper 2010, p.
1363). They also disperse easily from
upstream areas through drift (Minshall
et al. 1997, p. 2523) or from adult
dispersal from adjacent undisturbed
habitats (Hughes et al. 2003, p. 2151).
Because of the increased availability of
prey species (primary consumers), large
stonefly nymphs and other predatory
macroinvertebrates can dramatically
increase in abundance after a fire (Viera
et al. 2004, pp. 1253–1254; Herbst and
Cooper 2010, p. 1360; Malison and
Baxter 2010, p. 1335). For example,
Viera et al. (2004, p. 1251) found the
predaceous stonefly, Isoperla
(Perlodidae), had recovered in the first
post-fire year that did not experience a
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significant flood event. We would,
therefore, anticipate that under most
circumstances, if fires resulted in a
decrease in the availability of primary
consumer prey species for food of
Redrock stoneflies, such an effect would
be short-term in nature.
Because of the limited exposure of the
species to the effects of wildfires and
the expected resiliency of the species to
recover following any short-term habitat
alteration resulting from wildfires, we
find the wildfires are not a significant
threat to the Redrock stonefly or its
habitat.
Prescribed Fires
To avoid the detrimental effects of
large, high-severity fires and to restore
more natural fire disturbance patterns in
forest ecosystems of the western United
States, prescribed fires and mechanical
forest thinnings (selected removal of
trees) are being used as management
tools, particularly near wildland-urban
interfaces (Arkle and Pilliod 2010, p.
893). Prescribed fires are often
intentionally excluded from, or near,
riparian forests to avoid fire-associated
increases in sediment levels and other
habitat changes that could be
detrimental to ecologically sensitive
habitats and aquatic taxa (Arkle and
Pillirod 2010, pp. 893–894). Therefore,
prescribed fires in Arizona are usually
designed to avoid impacting riparian
and stream habitats. For example, the
U.S. Forest Service has formally
consulted with the Service under
section 7 of the Act on two prescribed
fires that they determined would have
an adverse effect on two listed species,
Gila topminnow (Poeciliopsis
occidentalis) and loach minnow
(Tiaroga cobitis), in a riparian or stream
community in Arizona: the Quien Sabe
Fire Management Treatment (Service
1991, pp. 8–9) and the Robinson Mesa
Prescribed Fire Project (Service 1999,
pp. 22–23). Both consultations included
mandatory terms and conditions to
reduce the adverse effects of project
implementation to listed species. We
anticipate that the exclusion of
prescribed fire from riparian areas,
along with conservation measures put in
place during prescribed fire planning for
other species, is adequate to minimize
impacts to the Redrock stonefly. The
Redrock stonefly’s resilience to wildfire,
discussed above, would also reduce the
effects of prescribed fire. Therefore, we
find that prescribed fires are not a
significant threat to the Redrock stonefly
or its habitat.
Recreation
The Redrock stonefly sites or their
watersheds occur on private, State, and
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Federal lands. The Federal lands are
managed for recreation and other
purposes, and some level of recreation
occurs on every stream occupied by the
Redrock stonefly. A study of outdoor
recreation trends in the United States
found increases in participation in most
of the activities surveyed, which
included bicycling, primitive or
developed-area camping, bird watching,
hiking, backpacking, and snowmobiling
(Cordell et al. 1999, pp. 221–321).
Human population growth trends are
expected to continue into the future
throughout the Southwest, leading to
higher demand for outdoor recreational
opportunities. In the arid Southwest, the
human desire to recreate in or near
water, and the relative scarcity of such
recreational opportunities, tends to
focus recreation impacts on riparian
areas (Winter 1993, p. 155; Briggs 1996,
p. 36).
Streams are popular hiking
destinations in Arizona. While there are
hiking opportunities at each of the
Redrock stonefly sites, actual use is
limited by their location in remote
rugged canyons with poor access or due
to land ownership restrictions (State
and private lands). Spring Creek and the
three lower Tonto Creek sites are
located in areas without easy road
access. The upper Tonto Creek site is
difficult to access because of private
land downstream of its location. The
Campbell Blue Creek site is located
along a forest road, leading to a private
ranch in a remote area in eastern
Arizona. The Redrock stonefly is not
affected by hiking in Oak Creek. The
Page Springs Oak Creek site, at the Page
Springs Hatchery, has hiking trails on
the adjacent uplands. The AGFD allows
very limited creek access from their
property, due to concerns of fish disease
transmission from the creek to the
hatchery. Redrock State Park only
allows visitor access along designated
trails; swimming or wading is
prohibited in Oak Creek. The Beaver
Creek Ranch is a private high school
that limits public access to the east side
of the creek. Recreational use is
primarily hiking through the area along
the west side of the creek.
Hiking in streams can be a source of
disturbance to stream invertebrates.
Aquatic invertebrates can be induced to
drift as a result of disturbance by hikers
within the stream. In one study,
increased numbers of hikers resulted in
increased densities of drifting aquatic
invertebrates (Caires et al. 2010, p. 555).
However, this is not likely to be a
significant effect, because aquatic
invertebrates are adapted to flash floods,
which cause a similar, but larger,
disturbance (Caires et al. 2010, p. 555).
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Caires et al. (2010, p. 555) found that
aquatic invertebrates areas disturbed by
hikers quickly recolonized from
upstream. Redrock stoneflies do not
intentionally drift, but if hiking causes
then to enter the water column, they
would be susceptible to fish predation
until they settled back down to the
stream bed. Future flood events could
carry Redrock stoneflies downstream to
unoccupied habitats. Because of the
limited opportunity for hikers in
streams occupied by the Redrock
stonefly and the likely, but short-term,
effects of hiking, this type of
recreational activity is not a significant
threat to the Redrock stonefly or its
habitat.
Off-road vehicle (ORV) use is another
form of recreation that can increase
sedimentation in streams by damaging
riparian vegetation and stream banks.
However, most Redrock stonefly sites
are either inaccessible or minimally
impacted by ORV use. The Oak Creek
sites are not accessible to ORV use. The
Page Springs site, at the Page Springs
Fish Hatchery, limits visitors to walking
trails on both sides of Oak Creek, fish
hatchery tours, and fishing. Also, ORV
use is prohibited at the Redrock
Crossing site at Red State Park. The Wet
Beaver Creek sites are inaccessible to
ORVs because the U.S. Forest Service
road leading to the site upstream of the
USGS gage is closed to all vehicular
traffic. The lower Wet Beaver Creek site,
near the Beaver Creek Ranch, is
protected by private land on the east
side and the closed U.S. Forest Service
road on the west side. Similarly, the
three Tonto Creek sites are either
located in a narrow canyon or have
private land at Bear Flats that blocks
access. The lower site is located in the
Hells Gate Wilderness, where
mechanized and motorized vehicle uses
are prohibited. The Spring Creek site is
located in a steep-walled canyon
without any road access. The Campbell
Blue Creek site is the only habitat that
may experience some ORV use because
there is a road paralleling the creek that
provides vehicle access into the area.
Therefore, due to the lack of access to
all but one of the known occupied sites,
we do not consider ORV use a threat to
the Redrock stonefly or its habitat.
In summary, we considered the
potential impacts to Redrock stonefly
habitat from recreational activities
primarily associated with hiking and
ORV use. We found there is limited
access to Redrock stonefly habitats for
these activities and very minor effects
when they occur. Therefore, we find
that recreation is not a significant threat
to the Redrock stonefly or its habitat.
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Urban and Rural Development
The effects of urban and rural
development on natural habitats are
expected to increase as human
populations increase. Consumer interest
in second home and retirement real
estate investments has increased
significantly in recent times within the
southwestern United States. Medina
(1990, p. 351) points out that many real
estate investors are looking for scenic
areas with mild climates to develop
properties that are within, or adjacent
to, riparian areas, due to their aesthetic
appeal and available water, especially in
the southwestern United States.
Arizona’s population increased by 28
percent from 2000 to 2009 (U.S. Census
Bureau 2010, p. 1). Over the same time
period, population increases in the
Arizona counties where Redrock
stoneflies occur are as follows: Yavapai
County (28 percent); Gila County (1.8
percent); and Apache County (1.8
percent) (U.S. Census Bureau 2010,
p. 1).
Increased urbanization and
population growth results in increased
demands for water development
projects. Collier et al. (1996, p. 16)
mentions that water development
projects are one of two main causes of
decline of native fish in the Salt and
Gila Rivers of Arizona, and municipal
water use in central Arizona increased
by 39 percent over 8 years (American
Rivers 2006, p. 1). Water for
development and urbanization is often
supplied by groundwater pumping and
surface water diversions from sources
that include reservoirs and the Central
Arizona Project’s allocations from the
Colorado River. The hydrologic
connection between groundwater and
surface flow of intermittent and
perennial streams is becoming better
understood as a result of new research.
Groundwater pumping creates a cone of
depression within the affected aquifer
that slowly extends outward from the
well site. When the cone of depression
intersects the hyporheic zone of a
stream (the transition zone between
surface water and groundwater), the
surface water flow may decrease, and
the subsequent drying of riparian and
wetland vegetative communities may
result (Webb and Leake 2006, p. 308).
Streamflow reduction from increased
groundwater use and surface water
diversion can have a dramatic impact on
stream habitat and associated
macroinvertebrate communities.
Artificial flow reductions frequently
lead to negative changes in aquatic
ecosystems, such as decreased water
depth, increased sedimentation, and
altered water temperatures and
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chemistry; all of these can reduce or
influence macroinvertebrate numbers,
richness, competition, predation, and
other interactions (Dewson et al. 2007,
pp. 401–411). Twenter and Metzger
(1963, p. 29) determined that permeable
sandstone beds are the primary source
of water for springs in the Page Springs
(also referred to as Cave Springs) and
Spring Creek areas, and much of the
perennial flow in Oak Creek is from
these springs. Twenter and Metzger
(1963, p. 14) determined that the
average base flow of Oak Creek just
above the springs complex during
winter months was 40 cfs (1.13 cms).
After adding the 36 cfs (1.01 cms)
inflow from springs and 16 cfs (0.45
cms) from Spring Creek, the base flow
increased to 92 cfs (2.6 cms) near the
mouth of the creek. There are six
springs, not including Page Springs,
immediately upstream of the Page
Springs Redrock stonefly site that
produces more than 10 gpm (37.8 lpm)
(ADWR 2009a, p. 268). Page Springs is
the second highest discharging spring in
the Verde River watershed, flowing at
29 cfs (0.82 cms) (Flora 2004, p. 38).
These springs and seeps in the Page
Springs area provide a large volume of
water to Oak Creek, where the Redrock
stonefly occurs (Mitchell 2001, p. 4). An
analysis of the Page Springs flow rate
between January 1, 1996, and February
9, 2000, detected a 15 percent decline in
flow (Mitchell 2001, p. 5). This analysis
period coincided with a severe to
extreme drought, and with the drilling
of three new wells upstream of Page
Springs (Mitchell 2001, p. 6). The
ADWR’s records show that three wells
have been drilled in close proximity and
up gradient of Cave Springs (Mitchell
2001, p. 6). Two of these wells pump
between 1,200 gpm (4,542 lpm) and
1,500 gpm (5,678 lpm), and are within
0.75 mi (1.2 km) of Page Springs. Given
their proximity, production rate, and
hydrological connectivity, groundwater
withdrawal by these wells could have a
direct impact on flow at Page Springs
(Mitchell 2001, p. 6). However, the
extent of the impact of these wells on
the spring cannot be determined
without long-term aquifer tests and
simultaneous discharge monitoring at
Cave Springs (Mitchell 2001, p. 6).
Wet Beaver Creek, upstream of the
USGS stream gage, is not affected by
diversions or wells, because the
watershed above this site is on the
Coconino National Forest. The Beaver
Creek Ranch, adjacent to the lower Wet
Beaver Creek site, has a small pond that
is filled by a diversion from the creek.
This pond is not large enough to impact
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Wet Beaver Creek base flow (Hedwall
2011, p. 1).
The Upper Tonto Creek headwaters
are fed by numerous springs, the largest
of which is Tonto Springs. Long-term
flow records from Tonto Springs show
little fluctuation in baseflow over a 20year period (Parker et al. 2005, p. 73).
There are numerous small wells located
on private lands and at U.S. Forest
Service campgrounds upstream of the
Redrock stonefly site. The ADWR
(2009a, p. 187) does not monitor water
depth in these wells, nor address the
wells’ impact to Tonto Creek baseflow.
The Redrock stonefly site on Spring
Creek is not affected by groundwater
wells as ADWR does not identify any
wells in the vicinity (2009a, p. 197). The
Campbell Blue Creek Redrock stonefly
site is located in an undeveloped
watershed with only two small parcels
of private land upstream of two ADWRregistered wells at the Blue River Ranch.
There are no other ADWR-registered
wells on Campbell Blue Creek (ADWR
2010, p. 1). There will likely be
continued human population growth in
the foreseeable future in some areas
around Redrock stonefly habitats that
could result in increased groundwater
usage. However, we do not have
sufficient information to reasonably
determine whether any future
groundwater would result in declines to
stream flows in Redrock stonefly
habitats. Overall, because of the low
level of water development currently
occurring within the watersheds that
support the species, water development
associated with urban and rural
development does not appear to
threaten the Redrock stonefly or its
habitat.
Summary of Factor A
Overall, our review found that the
best available scientific and commercial
information indicates that the Redrock
stonefly is not threatened by the
destruction, modification, or
curtailment of its habitat or range either
now or in the foreseeable future. The
Redrock stonefly spends most of its life
in a nymph stage in gravel and cobble
substrates of perennial streams.
Therefore, water quality and streamflow
are important habitat factors in
assessing the status of the species. In
considering potential threats due to the
degradation of water quality, we first
found that the Redrock stonefly, unlike
other species of stoneflies, is not known
to be particularly sensitive to changes in
water quality. This is due to anatomical
adaptations of the genus that allow it to
persist in warmer water with lower
oxygen levels compared to other
stoneflies. Because of these adaptations,
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any potential changes in water quality
are likely to have minimal impacts to
the Redrock stonefly. In addition,
studies by the State of Arizona, ADEQ,
at eight sites near Redrock stonefly
habitat found no water quality problems
that would be a concern for the stonefly.
We also considered the potential
impacts to water quality, particularly
increased sedimentation, from livestock
grazing in watersheds where the
Redrock stonefly occurs. Our analysis
found that grazing is not a significant
source of sedimentation because most of
the sites where the stoneflies occur have
either adequately managing grazing
programs or no grazing activity. In
addition, water quality assessments by
ADEQ did not indicate increased levels
of sediments or other pollutants of
concern.
We also considered the possible
habitat concerns related to the presence
of nonnative crayfish in streams
inhabited by the Redrock stonefly. We
found that while crayfish may increase
leaf litter decomposition rates and
reduce foraging habitat for Redrock
stoneflies, the availability of this habitat
is naturally limited by flood events.
Redrock stoneflies have other foraging
habitats available to them in the stream
channel, such as in gravel and cobble
substrates. Crayfish could also reduce
foraging habitat for stoneflies by feeding
on aquatic plants, if they served as
stonefly feeding substrate. However, as
Redrock stoneflies likely feed in leaf
litter and gravel and cobble substrates
(rather than on aquatic vegetation), and
their streams do not contain much
habitat for aquatic vegetation, this
change would not impact the stoneflies.
Finally, the potential for crayfish to
increase turbidity of the water through
foraging was not found to be a problem
because the stream habitats where the
stonefly occurs are high gradient with
fast velocity that flushes most mobilized
sediments downstream. Thus, the
nature of the Redrock stonefly’s feeding
strategies and habitat (fast-flowing water
over riffles of gravel and cobble
substrates) reduces the potential
impacts of nonnative crayfish.
We next considered the potential
impacts from wildfires and prescribed
fires to Redrock stonefly habitats. We
found that the species has limited
exposure to the effects of wildfires and
is expected to show high resiliency to
recover following any short-term habitat
alteration resulting from wildfires. In
addition, for prescribed fires, we
anticipate that the exclusion of riparian
areas, along with other conservation
measures, will likely be adequate to
minimize any potential impacts to the
Redrock stonefly or its habitat.
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We evaluated the potential impacts to
Redrock stonefly habitat from
recreational activities primarily
associated with hiking and ORV use,
because many of the streams where the
species occurs are popular recreational
destinations. However, we found there
is limited access for these activities to
the actual Redrock stonefly habitats, and
very minor effects are expected when
recreational activities occur near
Redrock stonefly habitat. This limits the
likelihood of any potential impacts to
the species associated with recreational
activities. We also assessed the risk of
stream flow declines as a consequence
to increases in human development and
associated groundwater use. While there
are potential effects to stream flows in
some areas, we found no indication that
groundwater withdrawals either
currently, or in the foreseeable future,
are likely to impact Redrock stonefly
habitats.
Finally, there has been no reduction
in the known range of the Redrock
stonefly (see discussion under
Distribution section above). The only
change in the distribution of Redrock
stonefly is the increase in the number of
known locations that resulted from a
recent increase in survey efforts.
Therefore, in conclusion, we find that
the best scientific and commercial
information available indicates that the
Redrock stonefly is not now, or in the
foreseeable future, threatened by the
destruction, modification, or
curtailment of its habitat or range to the
extent that listing under the Act as an
endangered or threatened species is
warranted at this time.
B. Overutilization for Commercial,
Recreational, Scientific, or Educational
Purposes
There is no information available
indicating that overutilization is a threat
to Redrock stonefly. Because of limited
access, collection of the species is not
likely to occur with any frequency. The
Redrock stonefly is currently known to
occur at 10 sites. Access to three, Tonto
Creek above Bear Flats, Page Springs,
and Redrock Crossing, is limited by
private land, State park, or State fish
hatchery. The two Wet Beaver Creek
sites have limited access due to closed
roads and private land. The three sites
on Tonto Creek, below the Bear Flat
Campground and the Spring Creek site,
have limited access due to rugged
terrain and poor road conditions. There
is no commercial or recreational use for
Redrock stoneflies. Further, even though
small collections for scientific and
educational purposes may occasionally
occur, we do not believe these
collections are large enough in
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magnitude to constitute a threat to the
species. Therefore, we conclude that the
best scientific and commercial
information available indicates that
Redrock stonefly is not threatened now
or in the foreseeable future from
overutilization for commercial,
recreational, scientific, or educational
purposes.
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C. Disease or Predation
We have no information that disease
may be a threat to Redrock stonefly.
However, potential impacts from
predation by native fish, nonnative fish,
and nonnative crayfish are discussed
below.
Predation by Native Fish
Native fish species, found in some or
all of the Redrock stonefly sites, that
may feed on Redrock stoneflies include:
Roundtail chub (Gila robusta), Gila chub
(G. intermedia), headwater chub (G.
nigra), longfin dace (Agosia
chrysogaster), speckled dace
(Rhinichthys osculus), and Sonoran
sucker (Catostomus insignis) (Rinne
1992, p. 39; Pilger et al. 2010, p. 307).
The Oak Creek sites are also considered
historical Gila trout (Oncorhynchus
gilae) habitat (Service 2003, p. 6), and
the Campbell Blue River site, although
outside their historical range, may
contain introduced Apache trout
(Oncorhynchus apache) (Service 2009b,
p. 12). These two trout feed upon
Redrock stonefly and other aquatic
insects (Behnke 1992, p. 43).
Native fish predation is not likely to
negatively impact Redrock stoneflies.
Aquatic macroinvertebrates, like
Redrock stonefly, have adapted over
time to fish predation (including small
body size, cryptic coloration, and
nocturnal activity) so that they are
affected little by changes in fish density
(Allan 1982, p. 1454). Two studies
found that when fish numbers were
reduced (Allan 1982, p. 1454) or
increased (Culp 1986, p. 146), there
were no significant effects on stoneflies
and other macroinvertebrates. The
stonefly, Hesperaperla (Perlidae),
experienced decreased sculpin (Cottus
sp.) predation when hiding cover was
available (Brusven and Rose 1981, p.
1447). Flecker and Allan (1984, p. 311)
found that fish predation had very little
effect on macroinvertebrate taxa and
individuals regardless of substrate size
(embedded or un-embedded gravel and
cobble substrate). Fish predation may be
negligible if fish are feeding primarily
on ‘‘surplus’’ secondary production of
macroinvertebrates that exceeds the
local carrying capacity.
The vulnerability of large predatory
stonefly to fish predation is largely a
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function of their exposure, large size,
and active foraging habits (Meissner and
Muotka 2006, p. 428). However, most
Perlidae stoneflies, including
Anacroneuria, forage at night to avoid
predators that seek prey visually
(Zanetell and Peckarsky 1996, p. 574).
Where focused predation on predatory
stoneflies occurs, it can decrease
stonefly density in two ways: Direct
consumption by predatory fish, or
apparent emigration to an area with
fewer fish (Feltmate and Williams 1989,
p. 1579). Stoneflies also modify habitat
use to avoid predation by selecting
larger substrate on which they are less
vulnerable (Brusven and Rose 1981, p.
1447; Feltmate et al. 1986, p. 1587).
Because of the findings of past studies
showing a lack of effect of predation on
stoneflies and the ability of stoneflies to
avoid exposure to predation, we find
that predation by native fish is not a
significant threat to Redrock stonefly.
Predation by Nonnative Fish
Nonnative fish are found in the
majority of aquatic communities in
Arizona, including the Redrock stonefly
sites. Holycross et al. (2006, pp. 14–15)
found nonnative fish species in 64
percent of the sample sites in the Agua
Fria watershed, 85 percent of the sample
sites in the Verde River watershed, 75
percent of the sample sites in the Salt
River watershed, and 56 percent of the
sample sites in the Gila River
watershed. In total, nonnative fish were
observed at 41 of the 57 sites surveyed
(72 percent) across the Mogollon Rim in
Arizona (Holycross et al. 2006, p. 14).
Several studies have been conducted
that analyzed the effects of nonnative
fish predation on predaceous aquatic
invertebrates like the Redrock stonefly.
Pilger et al. (2010, pp. 306–307, 311,
319–321) found the nonnative brown
trout (Salmo trutta), rainbow trout,
flathead catfish (Pylodictis olivaris),
green sunfish (Lepomis cyanellus),
smallmouth bass (Micropterus
dolomieu), and yellow bullhead
(Ameiurus natalis) preyed more
frequently on predaceous aquatic
invertebrates than did native fish
species. The study also found stonefly
remains in rainbow trout and yellow
bullhead stomach contents (Pilger et al.
2010, pp. 316–317). Other studies
(Nystrom et al. 2003, p. 603; Meissner
and Muotka 2006, pp. 428–429; Herbst
et al. 2009, pp. 1336–1337) also found
that trout prefer large active prey such
as predatory invertebrates, which may
include the Redrock stonefly. In
Argentina, Molineri (2008, p. 111) found
Anacroneuria densities lower in streams
with introduced rainbow trout than in
streams with a single native fish species.
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In a second study, introduced trout were
also found to decrease invertebrate
predaceous stonefly abundance when
compared with paired fishless streams
(Herbst et al. 2009, p. 1330). Herbst et
al. (2009, p. 1337) also found that two
of the three abundant predaceous
stoneflies declined with trout
introductions, whereas the third species
was unaffected.
In streams where a previously
nonexistent feeding guild (a group of
organisms that feed on resources in
similar ways) has become established by
the presence of a nonnative fish,
macroinvertebrate community-level
effects are likely to be more detectable.
For example, introduced brown trout in
the Shag River, New Zealand, occupy
the diurnal invertebrate drift feeder
niche (species that feed on drifting
macroinvertebrates during the day),
which was not previously filled by
native fish (Flecker and Townsend
1994, p. 805; Nystrom and McIntosh
2003, p. 280). Macroinvertebrate
numbers and densities were lowest in
the brown trout-occupied channels
(Flecker and Townsend 1994, pp. 801–
802). The effects of introduced trout on
the macroinvertebrate community of
previously fishless streams was also
studied by Flecker (1992, p. 443), who
compared differences in invertebrate
drift timing between streams with an
introduced drift feeder (rainbow trout)
and nearby fishless streams. Where trout
were introduced, invertebrate drift
peaked at night, whereas the drift
occurred at all times in the fishless
streams. These studies indicate some
potential impacts of nonnative fishes on
stream invertebrates.
The studies described above involved
nonnative fish that were stocked into
previously fishless streams or streams
with extremely low native fish diversity.
None of the streams occupied by the
Redrock stonefly were fishless prior to
nonnative fish establishment. As a
result of evolving in habitat already
containing native predatory fish, the
Redrock stonefly has likely developed
effective anti-predator behavior (Sih et
al. 2010, p. 610). Also, in North America
introduced nonnative trout co-exist
with, or have replaced, native trout,
rather than being released into streams
without trout. So the introduced trout
are not a novel predatory threat that
Redrock stoneflies, in Oak, Wet Beaver,
and the Campbell Blue Creeks, have not
experienced (Flecker and Townsend
2003, p. 805). Tonto and Spring Creeks
are not considered historic native trout
habitat (Service 2003, p. 4). Therefore,
we conclude that the anti-predatory
behaviors of Redrock stoneflies are
likely sufficient to prevent nonnative
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trout from being a significant threat to
the Redrock stonefly.
Yellow bullheads, a nonnative fish
species, do represent a previously
nonexistent feeding guild in Arizona.
They are nocturnal tactile feeders that
forage along the stream bottom
(Reynolds and Casterlin 1977, p. 132).
Yellow bullheads are found in Oak, Wet
Beaver, Tonto, and Spring Creeks, and
are likely present in the Redrock
stonefly sites. However, the Redrock
stonefly may have specific behaviors to
avoid predation by fish. For example,
Moore and Williams (1990, p. 52) found
that when the stonefly Pteranarcys
dorsata was touched by sculpin and
suckers feeding along the stream
bottom, it froze and, if attacked, feigned
death by curling up and extending its
cerci (paired appendages on the
posterior body segment) as spines. This
reduced handling success or feeding
¨ ¨
ability by fish. Otto and Sjostrom (1983,
p. 203) also found that the stonefly
Dinocras cephalotes used this antipredator strategy to avoid trout
predation. We do not know if this antipredator strategy is used by Redrock
stoneflies to avoid yellow bullhead
predation, but we expect that this or
other anti-predatory behaviors likely
diminish any potential threat to the
species posed by yellow bullheads.
Predation by Crayfish
Predatory activities by introduced
crayfish can affect aquatic
macroinvertebrates by direct predation
and increased macroinvertebrate drift as
escaped prey escape and incidental
dislodgment by crayfish foraging.
Research indicates that crayfish are
primarily carnivorous as juveniles
before becoming omnivorous or even
herbivorous as they mature (Bondar et
al. 2005, p. 2633; Flinders and
Magoulick 2007, p. 775). However,
Momot (1995, pp. 34, 38) states that the
crayfish’s role as a predator has been
greatly underestimated.
Fernandez and Rosen (1996, p. 3)
studied the effects of crayfish on a lowelevation semi-desert stream and a highmountain stream in Arizona. They
concluded that crayfish predation can
noticeably reduce aquatic vertebrate and
macroinvertebrate species diversity and
destabilize food chains in riparian and
aquatic ecosystems. However, specific
information on nonnative crayfish
predation on macroinvertebrates, or
specifically stoneflies, is less
conclusive. Some studies suggest that
slow-moving organisms (unlike the
Redrock stonefly) kept in enclosures
with crayfish (for example, leeches
(Hirudinea), dragonflies (Odonata),
caddisflies (Trichoptera), isopods, and
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mollusks) are preyed on by crayfish,
whereas more mobile prey or prey living
in sediments (for example, trout fry,
chironomids, and stoneflies) were less
affected by crayfish (Hanson et al. 1990,
p. 78; Stenroth and Nystrom 2003, p.
472). For example, Fernandez and
Rosen (1996, p. 10) found significantly
lower macroinvertebrate numbers and
biomass (primarily slow-moving
caddisflies, snails, and mussels) in
crayfish-occupied sites than in
unoccupied sites in the White
Mountains, Arizona. Crayfish reduced
slow or immobile invertebrate numbers
and biomass in other studies as well
(Hanson et al. 1990, p. 78; Perry et al.
1997, p. 124; Stenroth and Nystrom
2003, p. 472; Olsson et al. 2009, p.
1735).
One study found a negative
relationship between crayfish numbers
and invertebrates, such as stoneflies, as
a result of crayfish predation. Charlebois
and Lamberti (1996, pp. 556, 560) found
lower macroinvertebrate numbers,
including Perlid stoneflies, in areas with
both low and high crayfish densities in
a Michigan stream. They concluded that
invasive crayfish can significantly affect
macroinvertebrate numbers. However,
when Bobeldyk and Lamberti (2008, pp.
268–269) returned 10 years later, they
found that, while macroinvertebrate
numbers were still significantly higher
in areas without crayfish, areas with
high and intermediate crayfish densities
were dominated by highly mobile
stoneflies and mayflies. This later study
substantiates the conclusion from
studies discussed above: more mobile
aquatic macroinvertebrate species, such
as the Redrock stonefly, may not be
significantly impacted by crayfish
predation.
Crayfish predation on
macroinvertebrates may be more
pronounced in coldwater streams that
lack crayfish predators, such as
largemouth bass (Micropterus
salmoides) and smallmouth bass (Hill
and Lodge 1995, p. 310; Charlebois and
Lambertii 1996, p. 560). Hill and Lodge
(1994, p. 2122; 1995, p. 310) found
higher macroinvertebrate numbers in
enclosures that contained both bass and
crayfish and attributed this to decreased
crayfish feeding on vegetative cover and
less foraging time in the presence of
bass predation. In the cool-water
streams occupied by the Redrock
stonefly (the two uppermost Tonto
Creek sites and the Campbell Blue Creek
site), crayfish may not experience a high
degree of fish predation; therefore,
crayfish may not be limiting their
foraging time. In contrast, green sunfish
and yellow bullhead are found in the
lower three Tonto Creek and Spring
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Creek Redrock stonefly sites. These
species are crayfish predators (Pilger et
al. 2010, pp. 319, 321). Wet Beaver
Creek and Oak Creek contain
smallmouth bass and yellow bullhead.
These crayfish predators may decrease
crayfish-predation on
macroinvertebrates, such as the Redrock
stonefly in Oak, Wet Beaver, the lower
three Tonto, and Spring Creek sites.
Crayfish are tactile predators and
some stonefly nymphs have evolved
appropriate defenses from predation
such as retreat, deflection of an attack
by reflex bleeding (fluid is forcibly
expelled from pores on the legs), and
spacing. Sedentary prey have been
found to be more vulnerable than
mobile prey to tactile predators (Allan
and Flecker 1988, p. 502); therefore,
upon encountering a crayfish, stoneflies
rapidly retreat rather than freezing to
minimize the risk of being caught
(Moore and Williams 1990, p. 53).
Reflex bleeding or auto-hemorrhaging is
known to be used by at least four
Plecoptera genera in two families:
Pteronarcidae (Pteronarcys (Moore and
Williams 1990, p. 50) and Peltoperla
(Benfield 1974, p. 740)), and Perlidae
(Agnetina and Acroneuria (Bukantis and
Peckarsky 1985, p. 202)). This is used as
a defense only when retreat from the
predator fails and capture occurs.
Crayfish that are sprayed immediately
drop the stonefly and clean their
antennae and mouthparts before
continuing to forage (Moore and
Williams 1990, p. 50). The spacing of
nymphs may also serve as a deterrent to
predation. Some stonefly nymphs
display aggressive behavior towards
each other when they come in close
contact (Moore and Williams 1990, p.
54). By avoiding close contact and high
densities, Redrock stoneflies may
reduce their susceptibility to predation
by decreasing the time and exposure to
predators (Tinbergen et al. 1967, p. 308;
Moore and William 1990, p. 55).
Crayfish may also cause
macroinvertebrate drift or movement
within the water column indirectly by
incidentally dislodging them during
foraging, or directly by attempted
predation (Charlebois and Lamberti
1996, p. 557). As discussed earlier,
predator-induced drift is a predatoravoidance mechanism used by
macroinvertebrates that swim well,
whereas poor swimming invertebrates
(which would include Redrock
stoneflies) crawl rather than drift, when
approached by predators (Malmqvist
and Sjostrom 1987, p. 401; Peckarsky
1996, p. 1902). Poor swimmers would
be susceptible to fish predation if
crayfish were to induce their drift up
into the water column, especially during
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the day (Flecker 1992, pp. 1–12; Radar
and MacArthur 1995, pp. 7–8).
Therefore, Redrock stoneflies crawl
rather than drift to avoid crayfish
predation, and so reduce the likelihood
of predation by crayfish.
In conclusion, because of the
expected limited exposure of the
Redrock stoneflies to crayfish and the
stonefly’s ability to avoid predation, we
conclude that nonnative crayfish do not
threaten the Redrock stonefly.
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Summary of Factor C
Disease is not known to be a threat to
Redrock stonefly. Native fish, nonnative
fish, and nonnative crayfish are found
in Redrock stonefly habitat and likely
prey on all available food resources,
including the Redrock stonefly.
However, we have no evidence to
suggest that predation has been, or will
be, a threat to the Redrock stonefly. The
species has numerous morphological
and behavioral adaptations that may be
used to avoid predation by fish or
crayfish. Aquatic macroinvertebrates
and, presumably, Redrock stoneflies are
well-adapted to fish predation, whether
from native or nonnative species. While
crayfish do feed on other aquatic
macroinvertebrates, because of its
mobility to avoid exposure to crayfish
predation, the Redrock stonefly is not
expected to be significantly affected.
Consequently, we conclude that the best
commercial and scientific information
available indicates that the Redrock
stonefly is not now, or in the foreseeable
future, threatened by disease or
predation to the extent that listing under
the Act as an endangered or threatened
species is warranted at this time.
D. The Inadequacy of Existing
Regulatory Mechanisms
The Arizona Department of
Agriculture has the primary authority to
manage insects in the State of Arizona.
They currently do not provide any
regulatory protection for the Redrock
stonefly. Because we have not found
any existing or future threats to the
Redrock stonefly, we believe this lack of
direct regulatory protection is
acceptable. However, several
mechanisms exist that provide some
indirect protection for the Redrock
stonefly and its habitat from various
forms of disturbance and habitat loss,
and these are described below.
Redrock stoneflies may derive some
indirect conservation benefit from their
co-occurrence with other species listed
as endangered or threatened under the
Act and their critical habitat in Arizona.
For example, the Campbell Blue Creek
was designated as loach minnow critical
habitat in 2007 (72 FR 13355; March 21,
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2007). The Service is currently
reevaluating loach minnow critical
habitat and is proposing approximately
709 mi (1,141 km) of streams as critical
habitat (75 FR 66482; October 28, 2010).
The Service has also proposed 726 mi
(1,168 km) of streams as critical habitat
for spikedace (Meda fulgida) (75 FR
66482; October 28, 2010). These
proposed critical habitat segments
overlap the Redrock stonefly sites on
Oak, Campbell Blue, Wet Beaver, and
Spring Creeks. The Wet Beaver Creek
site upstream of the USGS gage and the
Upper Tonto Creek sites upstream of
Houston Creek were not proposed for
critical habitat designation. If the
proposed areas are included in critical
habitat for one or both endangered
fishes, some limited benefits for the
Redrock stonefly may occur. Critical
habitat only applies to Federal actions
and would only consider the impacts to
habitat for the fishes; however, there is
sufficient overlap in habitats with the
Redrock stonefly, so some conservation
benefits could occur.
The National Wild and Scenic Rivers
System (NWSR System) was created by
Congress in 1968 (Pub. L. 90–542; 16
U.S.C. 1271 et seq.) to preserve certain
rivers with outstanding natural,
cultural, and recreational values in a
free-flowing condition for the enjoyment
of present and future generations. This
NWSR System is notable for
safeguarding the special character of
these rivers, while also recognizing the
potential for their appropriate use and
development. It encourages river
management that crosses political
boundaries and promotes public
participation in developing goals for
river protection. The U.S. Forest
Service’s policy at FSH 1909.12,
Chapter 8.12 states that management
prescriptions for eligible rivers should
provide the following protection:
(1) Free-flowing characteristics cannot
be modified.
(2) Outstandingly remarkable values
must be protected, and to the extent
practicable, enhanced.
(3) Management and development of
the river and its corridor cannot be
modified to the degree that eligibility or
classification would be affected.
The Apache-Sitgreaves National
Forest recently submitted an eligibility
report, which recommended that
Campbell Blue Creek be included in the
NWSR System (USDA 2010, pp. 83–87).
This Redrock stonefly site is located in
Eligible Segment 3, which has the
proposed classification as
‘‘Recreational.’’ ‘Recreational’’ river
sections are readily accessible by road
or railroad, may have some
development along their shorelines, and
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may have undergone some
impoundment or diversion in the past
(USDA 2010, p. 1). During the interim
period, until Congress approves the
designation, eligible rivers must be
managed under the same guidelines as
if designated. Therefore, the Redrock
stonefly site on Campbell Blue Creek
currently receives protection as if the
creek was designated part of the NWSR
System (USDA 2006, p. 22). This
protection entails specifically the
Campbell Blue Creek’s free-flowing
condition and outstanding remarkable
values. Free-flowing is defined in part
in the NWRS Act as without
impoundment, diversion, straightening,
rip-rapping, or other modification of the
waterway (16 U.S.C. 1286(b)); all of
which benefits the Redrock stonefly and
its habitat in Campbell Blue Creek.
An Instream Flow Water Right Permit
with the ADWR is a surface water right
that remains in-situ or ‘‘in-stream,’’ is
not physically diverted or
consumptively used, and is for
maintaining the flow of water necessary
to preserve wildlife, including fish and
recreation (ADWR 2009a, pp. 29–30).
The Tonto National Forest has an
instream flow water right (permit
number 96757) for Christopher Creek,
which drains into Tonto Creek at one of
the Redrock stonefly sites. The Tonto
National Forest also has pending
instream flow water right applications
for Tonto (application number 33–
96684) and Haigler (application number
33–96571) Creeks. Both of these
applications are currently being
protested (Nelson 2011, p. 1). The Tonto
National Forest is also compiling an
instream flow water right application for
Spring Creek (application number 33–
96815). The Coconino National Forest
has an instream flow water right permit
on Spring Creek, an important perennial
tributary to Oak Creek (permit number
90114) and a pending instream flow
water right for Oak Creek (application
number 33–90106). Once in place, these
instream water rights will protect
enough flow to provide for Redrock
stonefly habitat in perpetuity.
Because we have found no other
existing or future threats that warrant
listing the Redrock stonefly, and some
conservation mechanisms are currently
in place, we conclude that the best
scientific and commercial information
available indicates that the Redrock
stonefly is not now, or in the foreseeable
future, threatened by the inadequacy of
existing regulatory mechanisms to the
extent that listing under the Act as an
endangered or threatened species is
warranted at this time.
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E. Other Natural or Manmade Factors
Affecting Its Continued Existence
Climate Change and Drought
Projected future climate change is
most likely to affect aquatic species in
the southwestern United States, like the
Redrock stonefly, through reduced
surface water availability resulting from
lower water flows from decreased
precipitation. Periods of drought in the
Southwest are common, but the
frequency and duration of dry periods
may be altered by future climate change.
Global climate change, and associated
effects on regional climatic regimes, is
not well understood, but the predictions
for the Southwest indicate less overall
precipitation and longer periods of
drought. Seager et al. (2007, p. 1181)
predict, based on broad consensus
among 19 climate models, that the
Southwest will become drier in the 21st
century and that the transition to this
drier state is already underway. The
increased aridity associated with the
current ongoing drought will become
the norm for the Southwest within a
timeframe of years to decades, if the
models are correct (Jacobs et al. 2005, p.
438; Shaw et al. 2005, p. 280; Seager et
al. 2007, p. 1183).
Exactly how climate change will
affect precipitation patterns is less
certain because precipitation
predictions are based on continentalscale general circulation models that do
not yet account for land use and landcover-change effects on climate.
Consistent with recent observations in
changes from climate, the outlook
presented for the Southwest predicts
warmer, drier, drought-like conditions
(Jacobs et al. 2005, p. 437; Shaw et al.
2005, pp. 280–281; Seager et al. 2007, p.
1183; Hoerling and Eischeid 2007, p.
19). A decline in water resources, with
or without climate change, will be a
significant factor in the watersheds of
the desert Southwest.
One predicted effect of climate change
is an increase in summer monsoon rains
that would seasonally increase stream
flows. McGavock (2009, pp. 1–6)
describes the effects of increasing air
temperatures on base flow of streams
within the Verde River watershed,
which would apply to the Oak Creek
and Wet Beaver Creek Redrock stonefly
sites, and likely be applicable to the
other sites. Streamflow in Redrock
stonefly habitats may increase
seasonally as a result of summer
monsoon storm runoff. Mitchell et al.
(2002, p. 2262) defines the onset of the
Arizona summer monsoon period as
occurring when sea surface
temperatures are a minimum of 84
degrees Fahrenheit (29 degrees Celsius)
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in the Gulf of California. Earlier
attainment of this temperature correlates
with a stronger summer monsoon, with
the opposite being true if the trigger
occurs later. Gradual climate warming
could result in earlier and stronger
monsoons occurring more frequently
and leading to larger summer runoff in
Arizona streams (McGavock 2009, p. 3).
The resiliency of stoneflies, and
presumably the Redrock stonefly, to
flooding was discussed under wildfires
in Factor A. Flecker and Feifarek (1994,
p. 139) found that reductions in aquatic
macroinvertebrate densities, including
Anacroneuria sp., following floods
quickly improved in Venezuelan
streams. Aquatic macroinvertebrates
have several means to persist during
and after flood events such as highly
developed refuge-seeking behavior,
flexible life histories (such as delaying
metamorphism from eggs to young or to
adults to more favorable periods), and
the ability to recolonize flooded areas
rapidly (Scrimgeour and Winterbourn
1989, p. 42). We anticipate that given
the widely fluctuating occurrence of
summer flood events that presently
occur in Arizona (Grimm and Fisher
1989, p. 294) the Redrock stonefly is
likely to be resilient and persist if
stronger summer floods occur in its
habitat as a result of global climate
warming.
Another potential effect of climate
change is increased snowmelt runoff
into streams through a reduction in
sublimation. Sublimation is the process
of snow evaporating into the
atmosphere instead of melting, and can
remove large amounts of water from
snow that would have led to stream
runoff (Montesi et al. 2004, p. 763).
Sublimation occurs under cold
temperatures with intense sunlight,
especially in forested watersheds where
snow is held above the ground in trees,
where it can sublimate easier (Montesi
et al. 2004, p. 763). The Verde River
watershed is forested, and during cold
winters, can lose large amounts of snow
moisture to sublimation. Warmer winter
temperatures, as predicted, would
reduce sublimation, making more
snowmelt available for stream runoff
(McGavock 2009, p. 2).
However, if winter temperatures
warm too much, winter rains would be
expected to increasingly replace
snowfall. Snowfall is more conducive to
groundwater recharge because water
from melting snow has a longer time to
infiltrate into the ground than runoff
from rainfall. Base flows in these
streams that support Redrock stoneflies
would be expected to decline later in
the summer if groundwater recharge is
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decreased during future warmer winters
(McGavock 2009, p. 5).
Lower summer base flows in streams
could result in either the elimination of
available surface water (and loss of all
habitat), or the reduction in the amount
of available surface water. When stream
flows are reduced during the summer,
water quality generally decreases due to
increased water temperature, decreased
dissolved oxygen, and concentrated
pollutants. Redrock stoneflies would
likely use egg or nymphal diapause to
survive decreased habitat conditions if
climate change or other factors result in
reduced flows and degradation of
summer habitat conditions.
Climate change may be a significant,
long-term source of stress that indirectly
exacerbates other potential threats by
mechanisms, such as increasing the
likelihood of prolonged drought that
would reduce groundwater availability
and result in future habitat loss.
However, we do not currently have
sufficient information to determine the
potential effects of climate change on
the Redrock stonefly. Both the
magnitude (the extent of any specific
effects) and the imminence (when the
effects might occur) of the future effects
of climate change remain highly
uncertain. Climate change may serve to
exacerbate other current or future
concerns for habitat loss from other
factors. But because we have
determined that the Redrock stonefly is
not threatened by habitat loss, we
cannot predict with any certainty that
climate change will exacerbate future
habitat concerns sufficiently to consider
it a threat to the species. The degree of
impact would depend on the intensity
and longevity of Redrock stonefly
habitat changes that may occur, and
these changes cannot be predicted with
any certainty in the foreseeable future.
In addition, we find that the Redrock
stonefly’s adaptations to both warm and
cold water, low dissolved oxygen, and
sediment, discussed above in Factor A,
will lessen the potential impacts from
climate change. We conclude that the
best scientific and commercial
information available indicates that the
Redrock stonefly is not now, or in the
foreseeable future, threatened by other
natural or anthropogenic factors
affecting its continued existence, or that
these factors act cumulatively with
other potential threats to the extent that
listing under the Act as an endangered
or threatened species is warranted at
this time.
Finding
As required by the Act, we considered
the five factors in assessing whether the
Redrock stonefly is endangered or
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threatened throughout all or a
significant portion of its range. We
examined the best scientific and
commercial information available
regarding the past, present, and future
threats faced by the Redrock stonefly.
We reviewed the petition, information
available in our files, and other
available published and unpublished
information, and we consulted with
recognized stonefly experts and other
Federal agencies.
Our review of all the available
information in consideration of the five
factors does not support a determination
that any current activities or activities in
the foreseeable future are threatening
the Redrock stonefly or its habitat.
Under our Factor A analysis, we found
no significant modifications have
occurred to the habitats of the Redrock
stonefly and none are expected in the
foreseeable future. In addition, the
species is well-adapted to sustain itself
in areas with minor habitat alterations
associated with degraded water quality
or altered stream habitats. The only
known change in the range of the
species has been an increase in
distribution due to additional survey
efforts. Overutilization (Factor B) and
disease (Factor C) are not concerns for
this species. Predation (Factor C) by
both native and nonnative species likely
occurs, but the Redrock stonefly has
anti-predatory adaptations that are
expected to allow it to withstand the
anticipated predatory pressures. We
find that existing regulatory
mechanisms are sufficient (Factor D).
Furthermore, there are current
management practices and protections
in place that limit or prevent possible
negative impacts from human activities.
The only issue of concern we found
under Factor E is the potential effects of
climate change. Future climate change
could affect the habitat of Redrock
stonefly by reduced stream flows and
declining water quality. However, the
species appears to be adapted to
withstand some habitat degradation. At
this time, because of the uncertainties of
the local, specific effects of climate
change, we cannot adequately assess the
magnitude of those effects in the
foreseeable future, and therefore, find
that climate change is not a threat to the
Redrock stonefly.
Based on our review of the best
scientific and commercial information
available pertaining to the five factors,
we find that the threats are not of
sufficient imminence, intensity, or
magnitude to indicate that the Redrock
stonefly is in danger of extinction
(endangered), or likely to become
endangered within the foreseeable
future (threatened), throughout all or a
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significant portion of its range (see
‘‘Significant Portion of the Range’’
below). Therefore, we find that listing
the Redrock stonefly as an endangered
or a threatened species is not warranted
at this time.
Significant Portion of the Range
Having determined that the Redrock
stonefly is not in danger of extinction or
likely to become so within the
foreseeable future throughout all of its
range, we must next consider whether
there are any significant portions of the
range where the species is in danger of
extinction or is likely to become
endangered in the foreseeable future.
The Act defines an endangered
species as one ‘‘in danger of extinction
throughout all or a significant portion of
its range,’’ and a threatened species as
one ‘‘likely to become an endangered
species within the foreseeable future
throughout all or a significant portion of
its range.’’ The term ‘‘significant portion
of its range’’ is not defined by the
statute. For the purposes of this finding,
a portion of a species’ (Redrock stonefly)
range is ‘‘significant’’ if it is part of the
current range of the species, and it
provides a crucial contribution to the
representation, resiliency, or
redundancy of the species. For the
contribution to be crucial, it must be at
a level such that, without that portion,
the species would be in danger of
extinction.
In determining whether a species is
endangered or threatened in a
significant portion of its range, we first
identify any portions of the range of the
species that warrant further
consideration. The range of a species
can theoretically be divided into
portions in an infinite number of ways.
However, there is no purpose to
analyzing portions of the range that are
not reasonably likely to be significant
and endangered or threatened. To
identify only those portions that warrant
further consideration, we determine
whether there is substantial information
indicating that: (1) The portions may be
significant, and (2) the species may be
in danger of extinction there or likely to
become so within the foreseeable future.
In practice, a key part of this analysis is
whether the threats are geographically
concentrated in some way. If the threats
to the species are essentially uniform
throughout its range, no portion is likely
to warrant further consideration.
Moreover, if any concentration of
threats applies only to portions of the
species’ range that clearly would not
meet the biologically based definition of
‘‘significant’’ (i.e., the loss of that
portion clearly would not reasonably be
expected to increase the vulnerability to
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46265
extinction of the entire species to the
point that the species would then be in
danger of extinction), such portions will
not warrant further consideration.
If we identify portions that warrant
further consideration, we then
determine their status (i.e., whether in
fact the species is endangered or
threatened in a significant portion of its
range). Depending on the biology of the
species, its range, and the threats it
faces, it might be more efficient for us
to address the ‘‘significant’’ question
first, or the status question first. Thus,
if we determine that a portion of the
range is not ‘‘significant,’’ we do not
need to determine whether the species
is endangered or threatened there; if we
determine that the species is not
endangered or threatened in a portion of
its range, we do not need to determine
if that portion is ‘‘significant.’’
Applying the process described above
for determining whether a species is
endangered or threatened in a
significant portion of its range, we
considered status first to determine if
any threat or potential threat acting
individually or collectively threaten or
endanger the Redrock stonefly in a
portion of its range. We have analyzed
the potential threats to the species and
found that some threats, such as
potential habitat alteration from water
quality degradation from urban
development or decline in stream flows
from groundwater use, may be acting
only in geographic areas associated with
larger human populations. However,
based on our threats analysis, we found
that none of the potential threats, either
individually or collectively, are severe
enough to cause the Redrock stonefly to
be endangered or threatened in these
portions of its range, or in any portions
of its range that may meet the
biologically based definition of
‘‘significant.’’
Conclusion of 12-Month Finding
We do not find that the Redrock
stonefly is in danger of extinction now,
nor is it likely to become endangered
within the foreseeable future,
throughout all or a significant portion of
its range. Therefore, listing the Redrock
stonefly as endangered or threatened
under the Act is not warranted at this
time.
We request that you submit any new
information concerning the status of, or
threats to, Redrock stonefly to our
Arizona Ecological Services Office (see
ADDRESSES) whenever it becomes
available. New information will help us
monitor the stonefly and encourage its
conservation. If an emergency situation
develops for the Redrock stonefly, or
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any other species, we will act to provide
immediate protection.
jlentini on DSK4TPTVN1PROD with PROPOSALS
References Cited
A complete list of references cited is
available on the Internet at https://
www.regulations.gov and upon request
from the Arizona Ecological Services
Office (see ADDRESSES section).
VerDate Mar<15>2010
16:12 Aug 01, 2011
Jkt 223000
Authors
The primary authors of this notice are
staff members of the Arizona Ecological
Services Office.
Authority
The authority for this section is
section 4 of the Endangered Species Act
PO 00000
Frm 00058
Fmt 4702
Sfmt 9990
of 1973, as amended (16 U.S.C. 1531 et
seq.).
Dated: July 21, 2011.
Gregory E. Siekaniec,
Acting Director, U.S. Fish and Wildlife
Service.
[FR Doc. 2011–19447 Filed 8–1–11; 8:45 am]
BILLING CODE 4310–55–P
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02AUP1
Agencies
[Federal Register Volume 76, Number 148 (Tuesday, August 2, 2011)]
[Proposed Rules]
[Pages 46251-46266]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-19447]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2011-0047; MO 92210-0-0008-B2]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List the Redrock Stonefly as Endangered or Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 12-month petition finding.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list the Redrock stonefly
(Anacroneuria wipukupa) as endangered or threatened and to designate
critical habitat under the Endangered Species Act of 1973, as amended.
After review of all available scientific and commercial information, we
find that listing the Redrock stonefly is not warranted at this time.
However, we ask the public to submit to us any new information that
becomes available concerning the threats to the Redrock stonefly or its
habitat at any time.
DATES: The finding announced in this document was made on August 2,
2011.
ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R2-ES-2011-0047. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Arizona Ecological Services Office, 2321
West Royal Palm Road, Suite 103, Phoenix, AZ 85021. Please submit any
new information, materials, comments, or questions concerning this
finding to the above street address.
FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor,
Arizona Ecological Services Office (see ADDRESSES); by telephone at
602-242-0210; or by facsimile at 602-242-2534. If you use a
telecommunications device for the deaf (TDD), please call the Federal
Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(B) of the Endangered Species Act of 1973, as
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition
to revise the Federal Lists of Threatened and Endangered Wildlife and
Plants that contains substantial scientific or commercial information
that listing the species may be warranted, we make a finding within 12
months of the date of receipt of the petition. In this finding, we will
determine that the petitioned action is: (1) Not warranted, (2)
warranted, or (3) warranted, but the immediate proposal of a regulation
implementing the petitioned action is precluded by other pending
proposals to determine whether species are endangered or threatened,
and expeditious progress is being made to add or remove qualified
species from the Federal Lists of Endangered and Threatened Wildlife
and Plants. Section 4(b)(3)(C) of the Act requires that we treat a
petition for which the requested action is found to be warranted but
precluded as though resubmitted on the date of such finding, that is,
requiring a subsequent finding to be made within 12 months. We must
publish these 12-month findings in the Federal Register.
Previous Federal Actions
On June 25, 2007, we received a formal petition dated June 18,
2007, from WildEarth Guardians requesting that we list the Redrock
stonefly as either endangered or threatened and
[[Page 46252]]
that critical habitat be designated under the Act. This species was
part of a petition to list 475 species in the southwestern United
States. WildEarth Guardians incorporated all analyses, references, and
documentation provided by NatureServe in its online database at https://www.natureserve.org into the petition. This included information
produced by the Natural Heritage Network, particularly the Heritage
Data Management System compiled by the Arizona Game and Fish Department
(AGFD) (AGFD 2004, pp. 1-3).
Relative to the Redrock stonefly, the petition provided information
on the species' current distribution, indicating it was limited to Oak
Creek, Yavapai County, Arizona. The remaining information was general
in nature describing factors that influence the entire stonefly order.
The petition clearly identified itself as a petition and included the
identification information required at 50 CFR 424.14(a). We sent a
letter to the petitioners dated July 11, 2007, acknowledging receipt of
the petition and stating that the petition was under review. The 90-day
finding was published in the Federal Register on December 16, 2009 (74
FR 66866). This notice constitutes the 12-month finding on the June 18,
2007, petition to list the Redrock stonefly as endangered or
threatened.
Species Information
Taxonomy and Species Description
The Redrock stonefly is an aquatic insect in the Family Perlidae
and the Order Plecoptera. Immature stoneflies, or nymphs, are aquatic
and generally live in cold-water streams. The nymphs have external
gills, which may be present on almost any part of the body. Nymphs
appear very similar to adults but lack wings (Stewart and Harper 1996,
p. 218). Most stonefly nymphs are herbivorous, feeding on submerged
leaves and algae, but other stonefly species are predaceous and feed on
other aquatic macroinvertebrates (Stewart and Harper 1996, p. 217).
Stoneflies remain in nymph form for 1 to 3 years, depending on species,
before emerging and becoming terrestrial adults (Bouchard 2004, p. 77).
Adult stoneflies generally only survive for a few weeks, and emerge
only during specific times of the year. Some adult stoneflies do not
feed at all, but those that do are herbivorous.
The family Perlidae includes relatively large, predaceous
stoneflies. They have external gills found on three thoracic (middle
body) segments (Bouchard 2004, p. 85). The Anacroneuria genus is the
largest genus in the Perlidae family, primarily occurring in the
Neotropical regions of Central and South America (Jewitt 1958, p. 159;
Bispo and Froehlich 2004, p. 191). There are 231 described and 19
undescribed species within this genus occurring from the southernmost
United States to South America (DeWalt et al. 2010, p. 1). The genus
Anacroneuria expanded northward into Central America, Texas, and
Arizona about 4 million years ago after the formation of the Isthmus of
Panama, during the Pliocene Period (Fochetti and Tierno de Figueroa
2008, p. 374).
Anacroneuria was confirmed to exist in the United States when
Redrock stonefly was described from Yavapai County, Arizona (Baumann
and Olson 1984, pp. 489-492). Anacroneuria nymphs (immature stages)
were first collected in Oak Creek at Page Springs in 1975, and the
first adults were collected from Oak Creek at Redrock Crossing in 1978
(Baumann and Olson 1984, p. 489).
The Redrock stonefly is a large-winged stonefly. Adult male body
lengths range between 0.4 to 0.5 inches (in) (10 to 12 millimeters
(mm)), and female body lengths are 0.6 in (15 mm). Overall coloration
is the same between genders: yellow head, brown and yellow body with
bands bordering the midline. Redrock stonefly legs are covered with
small brown spines on the upper surface, and the abdomen has many small
spinules on the edges (Baumann and Olson 1984, pp. 489-492). Stewart
and Harper (1996, pp. 231, 255, 258) provide morphological characters
to separate Anacroneuria adults and nymphs from other Perlidae genera.
Anacroneuria adults and nymphs are distinguished from all other
southwestern Perlidae for having two ocelli (simple eyes) on top of
their head rather than three. The only other western Perlidae genus
with two ocelli is Neoperla, but it is not found in Arizona (Stewart
and Stark 2002, p. 350).
Ecology
Baumann and Olson (1984, pp. 489-492) is the only published paper
describing the Redrock stonefly. This paper does not provide any
specific habitat or ecology information on this species. However, the
following ecological information is available from published reports on
other Anacroneuria species. We presume that the information generally
applies to Redrock stonefly.
At early ages and small sizes, Anacroneuria nymphs are primarily
detrivorous, meaning they feed on decayed leaves, algae, and other
organic matter. Older larger nymphs are predaceous, feeding entirely on
other aquatic insects including Dipteran (true fly) larvae and
Ephemeropteran (mayfly) nymphs, and other smaller stonefly nymphs.
North American Perlidae stonefly nymphs, in addition to foraging in
riffle (shallow, flowing water) habitats, often forage within leaf
packs (Femenella and Stewart 1986, pp. 535-536). Neotropical
Anacroneuria nymphs forage in leaf litter as predators (Baptista et al.
2001, p. 251; Wantzen and Wagner 2006, p. 220); we assume that leaf
litter provides an important foraging habitat for Redrock stonefly
nymphs. Leaf litter availability varies in southwestern U.S. streams
(Schade and Fisher 1997, p. 612). Leaf litter can accumulate behind
large rocks, behind logs, along the stream margins where the current is
slower, and behind other obstructions in high-gradient streams (Hoover
et al. 2006, pp. 443-444). Intense local thunderstorms generate severe
flash floods, which may reduce leaf litter availability for that season
(Schade and Fisher 1997, pp. 612, 624). Predaceous stoneflies,
including the Redrock stonefly, must then be able to forage in riffle
areas outside of leaf litter when it is not available in their habitat.
Adult Anacroneuria do not eat; they apparently rely on the predaceous
diet of their late nymphal stages for reproductive organ and egg
development (Fenoglio 2003, pp. 2, 16).
Neotropical Anacroneuria have a multivoltine life cycle (more than
one life cycle, from egg to adult, occurs during a year) (Jackson and
Sweeney 1995, p. 122). Because multivoltine life cycles are unknown in
stoneflies from temperate climates (United States and Canada) (Brittain
1990, p. 4), we anticipate that the Redrock stonefly would have a
univoltine life cycle (only one life cycle from egg to adult per year).
Stoneflies use egg or nymphal diapause (a period of suspended
growth or development) during harsh summer conditions to allow them to
survive seasonally poor water conditions and low stream flows (Snellen
and Stewart 1979, p. 663; Brittain 1990, p. 8; Favret and DeWalt 2002,
p. 37). During summer diapause, stonefly eggs or nymphs suspend
development and remain buried in the moist stream bottom sediment until
optimal growth conditions return. Stoneflies, including Perlidae, also
use this summer diapause to survive in intermittent streams (streams
that only flow as a response to snowmelt or rain storm runoff and have
insufficient groundwater contribution to provide surface flow during
the summer) (Snellen and Stewart 1979, p.
[[Page 46253]]
1; Feminella 1996, p. 659; Miller and Golladay 1996, p. 685). The
Redrock stonefly may be expected to use diapauses during dry periods
when water conditions and quantity are low.
Aquatic macroinvertebrates drift, or move downstream in their
habitats, under different circumstances. Catastrophic drift occurs when
large flood events carry macroinvertebrates downstream (Brittain and
Eikland 1988, pp. 82-83). All aquatic macroinvertebrates are likely to
experience this drift event if they are unable to find suitable
protection during a flood event. This may also include drift from
substrate disturbance from other means such as hikers, livestock, or
vehicles moving across the stream. Aquatic macroinvertebrates may
behaviorally drift to colonize new habitats to reduce competition for
food and space (Brittain and Eikland 1988, p. 84). Predator-induced
drift may occur when they are disturbed by a foraging predator and
escape by allowing the water current to carry them away (Malmqvist and
Sjostrom 1987, p. 402). Intentional drifting, as in behaviorally or
predator-induced cases, is only practiced by those macroinvertebrates
that are capable swimmers (such as Baetid and Amelitid mayflies) and
can control when, where, and how far they drift (Malmqvist and Sjostrom
1987, p. 402). Drifting insects are very susceptible to fish predation;
they are out in the open water column where they are easily seen.
Intentional drift often occurs at night to avoid fish predation
(Flecker 1992, p. 438). Aquatic macroinvertebrates that are poor
swimmers, such as predaceous stoneflies, are less likely to purposely
drift because they would be susceptible to fish predation (Radar and
McArthur 1995, p. 8). However, in some cases, predaceous stoneflies may
drift when suitable foraging sites are separated by areas, such as
sand-bottom streams, with little hiding cover to crawl across. Large
crawling stoneflies, like the Redrock stonefly, are also susceptible to
fish predation where there is little cover. In contrast, areas of
continuous cover, such as cobble-bed streams, provide protection from
fish predation when stoneflies move from one area to another (Radar and
McArthur 1995, p. 1). The known Redrock stonefly sites are continuous
cobble-bedded streams, which reduces the need to drift to new areas.
Distribution
The Redrock stonefly is known to only occur in Arizona, and it was
initially described from specimens collected at two sites: Redrock
Crossing at Red Rock State Park and Page Springs on Oak Creek, Yavapai
County, Arizona (Baumann and Olson 1984, p. 492; AGFD 2004, p. 1).
Additional stonefly surveys were conducted to determine the Redrock
stonefly's current status and distribution (Service 2010a, p. 1).
During surveys in May and June 2010, adult Redrock stoneflies were
found at the Page Spring Fish Hatchery on Oak Creek and Wet Beaver
Creek, and near an Arizona Department of Environmental Quality (ADEQ)
Bear Flats sampling site on Tonto Creek (Service 2010, p. 1). Surveys
on West Clear Creek, east of Camp Verde in Yavapai County, did not
identify any Redrock stoneflies. Identification of adult specimens was
confirmed by stonefly experts (Kondratieff pers. comm. 2010, p. 1;
Baumann pers. comm. 2010, p. 1; Stark pers. comm. 2010, p. 1).
The ADEQ had previously collected Anacroneuria nymphs during water
quality monitoring on Campbell Blue Creek in Apache County in 2000;
four sites on Upper Tonto Creek in Gila County from 1995 to 2008;
Spring Creek in Gila County in 1998; and Wet Beaver Creek (upstream of
the Service's survey location) in 1995 (Spindler 2010a, p. 1). Species
identification was not possible because only Anacroneuria nymphs were
collected. However, because there are no other stonefly species in that
genus known from Arizona, we presume these nymphs represent collections
of Redrock stonefly.
In total, we now believe the Redrock stonefly occupies at least 10
sites within five different streams in central Arizona. As a result the
only known change in distribution of the species is the increase from 2
sites, from which it was initially described, to 10 sites where
additional surveys found it. The increased range is a result of
increased survey efforts. We suspect that if additional survey efforts
were employed for this species, its known range and number of
occurrences would likely expand as well. This is because the adult
flying form of the Redrock stonefly has the ability to easily disperse
into available habitats, and there are numerous other habitats in this
region of Arizona that would appear suitable to support Redrock
stoneflies. The species does not appear to be a habitat specialist, and
so we would expect to find it in other similar stream habitats if more
survey efforts were undertaken.
The current sites where the Redrock stonefly occurs span about 180
miles (mi) (288 kilometers (km)) east to west across the Central
Highlands Physiographic Region in Arizona and include the Verde and
Salt Rivers and Tonto Creek headwaters. Because of the high elevations
and associated higher rainfall and snowfall, these watersheds contain
the highest concentration of perennial streams (water present
throughout the year) in Arizona (Arizona Department of Water Resources
(ADWR) 2009a, p. 4). The Redrock stonefly may also occupy other un-
surveyed water bodies (for example, East Verde River, Dude and Canyon
Creeks, and numerous sites on the White Mountain Apache Indian
Reservation) located in this physiographic region. The Redrock stonefly
sites or their watersheds are found on the Coconino, Tonto, and Apache-
Sitgreaves National Forests. Descriptions of occupied areas on each
National Forest are provided below.
To date, the Redrock stonefly has been found only in perennial
streams. All sites are in moderate gradient (approximately 2 percent
slope), cobble-bedded streams, with overhanging streambank vegetation
including willow (Salix sp.), velvet ash (Fraxinus velutina), Arizona
alder (Alnus oblongifolia), and blackberry (Rubus sp.) (Service 2010a,
p. 1).
There is substantial variation in the stream size, elevation, and
water temperature in areas occupied by the Redrock stonefly, making
this species more of a generalist than most other stonefly species
(Brittain 1990, p. 2). Stream sizes range from Campbell Blue Creek (47
square-mi (122 square-km) watershed and 160 cubic-feet-per-second (cfs)
(4.5 cubic-meters-per-second (cms)) bankfull channel discharge) to Oak
Creek at Page Springs (355 square-mi (919 square-km) watershed and
1,400 cfs (39.6 cms) bankfull channel discharge). Bankfull channel
discharge relates to the relative frequent flow (occurs 2 out of every
3 years) that fills the river channel to the point of inundating the
floodplain (Rosgen 1996, p. 2-2). Elevations at Redrock stonefly sites
range from 3,460 feet (ft) (1,055 meters (m)) on Oak Creek below Page
Springs to 6,670 ft (2,033 m) on Campbell Blue Creek. Adjacent upland
vegetation ranges from mixed paloverde and cactus desert (Oak Creek at
Page Springs) to ponderosa pine (Pinus ponderosa) and mixed conifer
(Campbell Blue Creek). The majority of sites are located between 3,900
and 5,100 ft (1,190 and 1,555 m) in elevation. Seven of the 10 Redrock
stonefly sites are considered warm-water streams (streams located below
5,000 ft (1,524 m) elevation): Oak Creek (two sites), Wet Beaver Creek
(two sites), Spring Creek, and the two lower Tonto Creek sites
(Spindler 2010c, p. 1). The remaining three sites (streams above
[[Page 46254]]
5,000 ft (1,524 m)), Campbell Blue Creek and the two higher Tonto Creek
sites, are considered cold-water streams.
Coconino National Forest
Oak Creek is a perennial stream in Coconino and Yavapai Counties in
central Arizona. Average annual precipitation in Oak Creek Canyon is 28
in (71 cm) (ADWR 2009a, p. 247). Its two main tributaries are the West
Fork of Oak Creek and Pumphouse Wash on the Coconino National Forest.
Oak Creek base flow is maintained by springs at Indian Gardens, by Page
Springs, and from its Spring Creek tributary. Oak Creek, upstream and
downstream of the Redrock stonefly sites, flows through Coconino
National Forest, private lands, and State-owned lands. Redrock
Crossing, the farthest upstream Redrock stonefly site in Redrock State
Park, is located approximately 4.7 river miles (7.6 km) downstream from
the city of Sedona. The Page Spring site, at the Page Springs Fish
Hatchery which is owned and operated by the AGFD, is approximately 18.7
river miles (30 km) downstream of Sedona.
Wet Beaver Creek is located east of Interstate Highway 17 and north
of the city of Camp Verde in Yavapai County, Arizona. It is a tributary
to Beaver Creek, which eventually flows into the Verde River at Camp
Verde. The Redrock stonefly was collected at two sites on Wet Beaver
Creek. The ADEQ collected nymphs upstream of the U.S. Geological Survey
(USGS) stream gage and adults were also collected at the Beaver Creek
Ranch (Service 10a, p. 1). Both sites are located on the National
Forest; the downstream site is adjacent to private land.
Tonto National Forest
Tonto Creek originates on the edge of the Mogollon Rim at about
7,600 ft (2,300 m) in elevation in mixed conifer forest, dominated by
ponderosa pine. Average annual precipitation for the Upper Tonto Creek
watershed ranges from 22 to 30 in (56 to 76 cm) (ADWR 2009a, p. 173).
There are 10 different springs that produce more than 10 gallons per
minute (gpm) (38 liters per minute (lpm)) that contribute to Tonto
Creek (ADWR 2009a, p. 182). Tonto Spring at the headwaters of Tonto
Creek is the largest spring in the Tonto Creek Basin with a measured
discharge of 1,291 gpm (4,887 lpm) (ADWR 2009a, p. 180).
The ADEQ collected Redrock stonefly nymphs at four sites on Tonto
Creek: above Bear Flats; below the Christopher Creek confluence; below
the Haigler Creek confluence; and below Bear Flats, south of Kohls
Ranch (Spindler 2010a, p. 1). Two adult female Redrock stoneflies were
also collected at the Bear Flats Campground in June 2010. All Redrock
stonefly sites on Tonto Creek are on the Tonto National Forest. This
portion of Tonto Creek is predominantly U.S. Forest Service land, with
the exception of a private development at Bear Flats and Kohl's Ranch.
The Redrock stonefly sites downstream of Bear Flats and downstream of
the Haigler Creek confluence are located within the Hells Gate
Wilderness and managed by the U.S. Forest Service.
Spring Creek is located on the Tonto National Forest near the town
of Young, Gila County, Arizona. The Redrock stonefly site on Spring
Creek is downstream of the Brady Canyon confluence and has an 88
square-mi (228 square-km) watershed. Spring Creek eventually flows 11
mi (17.6 km) from this site into Tonto Creek. Annual precipitation
averages 24 in (61 cm) (ADWR 2009b, p. 173). Spring Creek is an
interrupted flow system with perennial water disappearing in wider
alluvial valleys (gently sloping areas with deep sediment deposits)
then resurfacing in narrow canyons. It is mapped as an intermittent
stream below its confluence with Walnut Creek (ADWR 2009a, p. 182,
Figure 5.3-6). There are no springs along Spring Creek or located
within its watershed that produce stream flows greater than 1 gpm (3.8
lpm) (ADWR 2009b, p. 182). ADWR (2009, p. 187) does not record any
wells located within the Spring Creek watershed.
Apache-Sitgreaves National Forests
Campbell Blue Creek originates southwest of Alpine, Apache County,
in eastern Arizona, and flows southeasterly for 17 river miles (27 km)
to its confluence with Dry Blue Creek in New Mexico. Perennial flow
initiates downstream of the Coleman Creek/Campbell Blue Creek
confluence. Campbell Blue Creek has one spring that produces at least
10 gpm (38 L pm), located downstream of the Redrock stonefly site (ADWR
2009b, pp. 351-352). All of the tributaries that drain into Campbell
Blue Creek are intermittent (ADWR 2009b, p. 352). The area receives an
average of 21 inches (53 cm) of precipitation per year (ADWR 2009b, p.
342).
Summary of Factors Affecting the Redrock Stonefly
Section 4 of the Act and its implementing regulations (50 CFR 424)
set forth procedures for adding species to, removing species from, or
reclassifying species on the Federal Lists of Endangered and Threatened
Wildlife and Plants. Under section 4(a)(1) of the Act, a species may be
determined to be endangered (in danger of extinction throughout all or
a significant portion of its range) or threatened (likely to become an
endangered species within the foreseeable future throughout all or a
significant portion of it range) based on any of the following five
factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
In making this finding, information pertaining to the Redrock
stonefly in relation to the five factors provided in section 4(a)(1) of
the Act is discussed below. In making our 12-month finding, we
considered and evaluated the best available scientific and commercial
information.
In considering what factors might constitute threats, we must look
beyond the mere exposure of the species to the factor to determine
whether the species responds to the factor in a way that causes actual
impacts to the species. If there is exposure to a factor, but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species such that the species warrants
listing as endangered or threatened as those terms are defined by the
Act. This does not necessarily require empirical proof of a threat. The
combination of exposure and some corroborating evidence of how the
species is likely impacted could suffice. The mere identification of
factors that could impact a species negatively is not sufficient to
compel a finding that listing is appropriate; we require evidence that
these factors are operative threats that act on the species to the
point that the species meets the definition of endangered or threatened
under the Act.
A. The Present or Threatened, Destruction, Modification, or Curtailment
of the Species' Habitat or Range
Under Factor A, we will discuss a variety of potential impacts to
Redrock stonefly habitat including: (1) Water
[[Page 46255]]
quality, (2) livestock grazing, (3) crayfish, (4) wildfires, (5)
prescribed fires, (6) recreation, and (7) urban and rural development.
The potential impacts of nonnative crayfish are discussed here related
to habitat alterations, and other impacts from crayfish are discussed
under Factor C below.
Water Quality
Impacts to aquatic habitats, especially from pollution, have been
identified as a concern for the Redrock stonefly (AGFD 2004, p. 2).
Most stonefly species are restricted to cold-water environments because
their small external gills require water with high dissolved oxygen
levels (Surdick and Gaufin 1978, p. 3; Covich 1988, p. 365; Brittain
1990, p. 2). In unpolluted, cold-water streams and rivers, dissolved
oxygen concentrations usually remain high, well above 80 percent
saturation, because oxygen solubility (ability to be absorbed in water)
increases as temperature decreases (Hauer and Hill 1996, p. 96). High
organic nutrient levels can also be detrimental because they cause
excessive microbial (microscopic organisms) growth. These organisms
consume oxygen from the water (Hauer and Hill 1996, pp. 96-97). Organic
pollution can also cause excessive algae growth, which can decrease
dissolved oxygen when the algae respires or absorbs oxygen at night
(Hauer and Hill 1996, p. 97) or when the vegetation dies and decomposes
(Jewell 1971, p. 1457). Because Plecoptera are considered sensitive to
low dissolved oxygen levels in water, their presence is often used for
monitoring water quality (Surdick and Gaufin 1978, p. 1; Udo et al.
1984, p. 189). However, stoneflies in the genus Anacroneuria are an
exception to this standard practice, because species in this genus are
well-established in warm-water neotropic regions of Central and South
America and can withstand lower dissolved oxygen levels (Stark and
Kondratieff 2004, p. 1; Fenoglio 2007, p. 220; Nelson 2008, p. 184;
Springer 2008, p. 274). Anacroneuria are often found in streams with
warm-water temperatures ranging from 75 to 78 degrees Fahrenheit (24 to
26 degrees Celsius) (Froehlich and Oliveira 1997, p. 1882; Fenoglio and
Rosciszewska 2003, p. 163), which limits available dissolved oxygen.
Anacroneuria are adapted to low dissolved oxygen levels by having egg
capsules with tiny, thin canals oriented perpendicularly to the surface
of the shell that enhance oxygen uptake compared to other stoneflies
(Fenoglio and Rosciszewska 2003, p. 163). As a result of these
adaptations, the Redrock stonefly may be tolerant of impaired water
quality, particularly elevated water temperature and excessive
nutrients that can lead to low dissolved oxygen.
Several researchers have reported that Anacroneuria are tolerant of
poor water quality conditions. In fact, due to its tolerance for low
dissolved oxygen and poor water quality, Tomanova and Tedesco (2007, p.
69) determined that Anacroneuria may not be a good indicator of water
quality. Baptista et al. (2007, p. 92) noted that in tropical streams,
Anacroneuria was an exception to the rule that Plecoptera are
considered sensitive to environmental degradation. In addition,
Anacroneuria were documented in numerous bioassessment reviews and
studies in South America in waters with high organic (nutrients)
levels, although less so than in unpolluted waters (Froelich and
Oliveria 1997, p. 183; Bispo et al. 2002, p. 413; Bispo and Oliveria
2007, p. 287). Bobot and Hamada (2002, p. 300) found that Anacroneuria
densities did not respond to suspended sediment caused by deforestation
in streams in central Brazil. In another study, Anacroneuria were the
only stoneflies found in streams under strong anthropogenic (human-
caused) influences (Bispo et al. 2002, p. 413). We presume that the
Redrock stonefly is similar to other species of stoneflies in the
Anacroneuria genus and would, therefore, be tolerant of poor quality
conditions, should these types of conditions be present in their
habitat.
The ADEQ is required by the Clean Water Act (33 U.S.C. 1251 et
seq.) to conduct a comprehensive analysis of water quality data
associated with Arizona's surface waters to determine whether State
water quality standards are being met and designated uses (such as
human contact, aquatic, and wildlife) are being supported. Since 1992,
the ADEQ has evaluated water quality at eight sites currently known to
be occupied by Redrock stonefly nymphs (Spindler 2010b, p. 1). The ADEQ
rated five of the eight sites, Oak Creek (two sites) and Tonto Creek
(three sites), as having impaired water quality as a result of
Escherichia coli (E. coli) bacteria level exceedance in 2006 and 2008
(Avila et al. 2009, pp. VR-33, VR-35, SR-64, SR-65). The ADEQ notes
that high E.coli levels, on their own, do not affect aquatic
invertebrates (Spindler 2010b, p. 1), and we do not expect them to
affect Redrock stoneflies. This parameter is measured for safety
thresholds for the human contact designated use (Marsh 2009, p. G-22).
The ADEQ found no other water quality concerns during these surveys.
Our review found no other information indicating water quality concerns
in the streams where Redrock stoneflies are known to occur.
Based on the results of ADEQ water quality analyses and the Redrock
stonefly's wide range of habitats and presumed tolerance to higher
levels of sedimentation and nutrient enrichment, we conclude that water
quality conditions in Arizona are not a significant threat to the
Redrock stonefly or its habitat.
Livestock Grazing
If livestock grazing is not well-managed, aquatic insects can be
negatively impacted by decreased riparian vegetation, stream bank
destabilization, and increases in sedimentation and water temperature
(Braccia and Voshell 2006, p. 269; McIver and McInnis 2007, p. 294).
Improper grazing use levels may lead to soil erosion from riparian and
upland vegetation removal, soil litter removal, increased soil
compaction from trampling, and increased bare ground (Kauffman and
Krueger 1984, p. 434; Schulz and Leininger 1990, pp. 297-298; Belsky et
al. 1999, p. 30). Excessive livestock grazing in upland watersheds can
also lead to bare, compacted soils, which in turn allow less water
infiltration, which generates increased rates of surface runoff and can
contribute to soil erosion as well as flooding and stream bank
alterations (Abdel-Magid et al. 1987, pp. 304-305; Orodho et al. 1990,
pp. 9-11). Increased soil erosion leads to higher sediment loads in
nearby waters, which can degrade instream and riparian habitat and
increase water turbidity. Perlidae stoneflies, like Redrock stoneflies,
may experience reduced respiratory ability when their gills are covered
by sediment (Lemly 1982, pp. 238-239). Sediment that becomes embedded
in the interstitial spaces around large substrate can smother insect
(such as stonefly) eggs and larvae, reduce forage for the nymphal
stage, and limit suitable egg depositing sites (Brusven and Prather
1974, p. 31; Waters 1995, pp. 65-66).
The ADEQ (Spindler 2010c, p. 1) classified the Redrock stonefly
sites as moderate gradient based on riffle-dominated cobble or gravel
or both substrate streams (Rosgen Stream Classification B3 channel
types) (Rosgen 1994, p. 174; Rosgen 1996, pp. 5-68, 5-72). The B3
stream types are moderately entrenched systems with channel gradients
of 2 to 4 percent. The channel bottom materials are composed primarily
of cobble (2.5 to 10 in (64 to 256 mm) intermediate axis diameter) with
a few boulders and lesser amounts
[[Page 46256]]
of sands and gravels. Rosgen (1994, p. 194) determined that B3 stream
types have low sensitivity to disturbance and low streambank erosion
potential. The large cobble substrate that is resistant to movement
during frequent flood events is also resilient to livestock
disturbance. Given the energy required to initiate movement of large
cobbles, these stream channel types do not rely on vegetation for
stability; the substrate size in itself provides stabilization.
Recent ADEQ water quality data do not show that livestock are
having a negative impact on water condition at any of the Redrock
stonefly sites, in the form of excess sediment or nutrients that are
contributing to impairment (Avila et al. 2009, pp. SR-64, SR-65, VR-33,
VR-35, VR-61, VR-62). The ADEQ sites that are impaired and the causes
of impairment are discussed above in the Water Quality section.
One reason that grazing is not affecting streams that provide
habitat for the Redrock stonefly is that many of the streams are in
areas with well-managed grazing or no grazing. In Coconino National
Forest, the Oak Creek sites are not on livestock grazing allotments.
Almost the entire Oak Creek corridor is excluded from livestock
grazing. The Wet Beaver Creek stonefly sites are also excluded from
livestock grazing. In the Apache-Sitgreaves National Forest, Campbell
Blue Creek is also excluded from livestock grazing within the
downstream segment where Redrock stoneflies were collected by ADEQ
(USDA 2009, p. 87).
In the Tonto National Forest, the five Upper Tonto Creek sites are
located on two livestock grazing allotments: Christopher Mountain/
Ellinwood and Diamond Butte. The Redrock stonefly sites in the
Christopher and Tonto Creeks are excluded from grazing due to their
topography (they are in very steep terrain), or they are located in
pastures that are not grazed. The Spring Creek site is not located on a
grazing allotment, but is used for the Heber-Reno Sheep Driveway on the
Tonto and Apache-Sitgreaves National Forests. Two permitted livestock
operators are authorized to use the driveway as part of their 10-year
grazing permits. The permitted sheep herding is currently managed
through Annual Operating Instructions that are prepared for the Long
Tom and Beehive/Sheep Springs allotments in coordination with the
livestock operators and six ranger districts on the two forests. The
Sheep Driveway is used to access summer grazing allotments on the
Apache-Sitgreaves National Forest from winter grazing lands located on
private property in Phoenix, Arizona. Approximately 8,000 permitted
sheep, plus 7 pack animals per band for the sheep herders and camp
tender, are authorized on the Sheep Driveway (USDA 2010a, pp. 1-2).
Sheep are kept out of all riparian areas except when crossing and
watering (USDA 2010a, p. 11). All riparian areas are excluded from use
as bedding grounds. The limited sheep grazing at established stream
channel crossings does not likely affect the Redrock stonefly. These
stream crossing sites have little to no riparian vegetation and no
potential to produce riparian vegetation because they are dry washes or
road surfaces, or they consist of large cobble and boulder substrate
(USDA 2010a, p. 3).
Livestock grazing is not threatening the habitat of the Redrock
stonefly, because the habitat has limited exposure to the effects of
grazing. Livestock are excluded from the Oak, Wet Beaver, and Campbell
Blue Creeks Redrock stonefly sites due to decisions of land managers or
property owners. The Tonto Creek Redrock stonefly sites are located in
areas difficult for livestock to access. Only one area is used as a
travel corridor for moving sheep (Spring Creek), and the stream
crossing sites are not likely to affect Redrock stoneflies. Therefore,
we find that grazing is not a significant threat to the Redrock
stonefly or its habitat.
Crayfish
Crayfish are not native to Arizona. The red swamp crayfish
(Procambarus clarkii) and the green or northern crayfish (Orconectes
virilis) were introduced in Arizona in the 1970s (Taylor et al. 1996,
p. 27; Inman et al. 1998, p. 3). The red swamp crayfish is not
currently found in any of the Redrock stonefly sites (Sorensen 2010, p.
1; USGS 2010a, p. 1). The northern crayfish, however, is found
throughout Arizona, including the following Redrock stonefly sites:
Tonto Creek drainage; Oak Creek drainage (Holycross et al. 2006, pp.
23, 40-44, 59); Verde River drainage (Inman et al. 1998, Appendix B;
Holycross et al. 2006, pp. 14, 20-28, 54-56); Salt River drainage
(Inman et al. 1998, Appendix B; Holycross et al. 2006, pp. 15, 29-44,
56-60); and Spring Creek drainage and Campbell Blue Creek drainage
(Holycross et al. 2006, pp. 25, 46, 55, 60).
Crayfish are known to affect aquatic macroinvertebrate habitat in
three ways: (1) By increasing leaf litter decomposition rates; (2) by
feeding on aquatic plants; and (3) by increasing turbidity and
sedimentation from bioturbation when crayfish are physically moving
through fine substrates. The following discussion addresses each of
these three mechanisms. Crayfish can also prey on macroinvertebrates,
and this is discussed under Factor C.
First, crayfish may reduce the amount of leaf litter in streams and
reduce the amount of forage and foraging habitat available to Redrock
stonefly nymphs. The nymphs feed on detritus when young; they then prey
upon other aquatic macroinvertebrates found in the leaf litter
(Fenoglio 2003, pp. 2, 16). Forested streams receive a large portion of
their energy input from allochthonous litter (mainly plant material
from terrestrial sources) (Minshall 1967, p. 147; Vannote et al. 1980,
p. 132; Wallace et al. 1997, p. 102). This litter, in the form of
leaves and wood, is an important food source and foraging area for
stream invertebrates (Wallace and Webster 1996, p. 120; Usio 2000, p.
608). Invertebrates that feed on leaf litter are called shredders and
consume course particulate organic matter in the stream channel.
Shredders convert coarse particulate organic matter into fine
particulate organic matter, which breaks down litter and provides
additional food sources for stream macroinvertebrates. In their native
range, crayfish serve an important function by shredding coarse
particulate organic matter into fine matter in litter-based food webs
(Usio 2000, p. 612; Creed and Reed 2004, p. 225).
However, nonnative crayfish feeding on leaf litter can
significantly reduce the time it would otherwise take to break down
leaf litter and may lower the amount of foraging area available to
native macroinvertebrates (Usio 2000, p. 612; Creed and Reed 2004, p.
231; Bobeldyk and Lamberti 2010, pp. 648, 652). Nonnative crayfish are
typically the largest invertebrate shredder in streams (Usio 2000, p.
609; Parkyn et al. 2001, p. 641). Studies show that reduced terrestrial
litter amounts in streams resulted in decreased abundance of
invertebrates (and their predators) that feed on large and fine
particulate organic matter (Wallace et al. 1997, p. 102; Bobeldyk and
Lamberti 2010, pp. 649, 652). Neotropical Anacroneuria nymphs feed on
the small invertebrates that occur in association with leaf litter and
leaf packs (accumulated piles of leaf litter) (Benstead 1996, p. 371;
Mathuriau and Chauvet 2002, p. 390; Wantzen and Wagner 2006, p. 220).
Redrock stonefly nymphs are expected to use leaf packs as foraging
habitat when leaf packs are available and have not been removed from
the site by flooding (Schade and Fisher 1997, p. 624). Redrock stonefly
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nymphs could have less available food and foraging habitat as a result
of nonnative crayfish feeding on the leaf litter and increasing the
rate of leaf breakdown. However, because leaf litter availability is
also affected by flood events, the Redrock stonefly would be expected
to be adaptable and to satisfy its foraging needs in other habitats
such as riffle areas. Therefore, the potential loss of some leaf litter
due to crayfish is not expected to impact Redrock stoneflies.
Second, crayfish may reduce the amount of living aquatic vegetation
in streams. Crayfish feed heavily on living aquatic plants (Chambers et
al. 1990, p. 90; Creed 1994, p. 2098; Nystrom and Strand 1996, pp. 678,
680). The northern crayfish feeds on and reduces aquatic vegetation
available in streams, removing food sources for herbaceous
invertebrates, which reduces macroinvertebrate habitat, and may cause a
decrease in available prey items as food for the Redrock stonefly. In
one example, Creed (1994, p. 2098) found that a filamentous alga
(Cladophora glomerata), an aquatic plant commonly fed upon by crayfish,
was at least 10-fold greater in aquatic habitats without crayfish in
Michigan streams. Filamentous alga is an important component of aquatic
vegetation that provides cover and food for macroinvertebrates that
predatory stoneflies may feed on.
However, we believe that crayfish feeding on aquatic plants is not
likely to impact the Redrock stonefly. This is because Redrock stonefly
nymphs occur in moderately steep-gradient streams with cobble
substrates that do not provide many areas with fine substrates or low
water velocities for herbaceous vegetation to establish and persist.
The three factors that limit aquatic vegetation growth in stream
channels are shade, large cobble substrate, and high water velocity,
and they are all present at all Redrock stonefly sites (Vannote et al.
1990, p. 132; Biggs 1996, p. 135; Riis and Biggs 2003, pp. 1495-1496;
O'Hare et al. 2010, pp. 6-7; Service 2010a, p. 1). We presume that
Redrock stoneflies, like most Anacroneuria, feed in leaf litter and
gravel and cobble substrates rather than in aquatic vegetation
(Tamaris-Turizo 2007, p. 1). Therefore, crayfish herbivory does not
significantly impact stonefly foraging habitat or prey availability.
Third, crayfish can increase turbidity (suspended sediment in the
water column) in wetlands and lakes as they move and forage for prey in
fine sediments (Statzner et al. 2000, p. 1039; Dorn and Wojdak 2004, p.
157). Many aquatic invertebrates depend upon open interstitial spaces
(small openings between rocks) in channel substrate (gravels and
cobbles). Excessive sediments in streams can fill the interstitial
spaces and reduce aquatic invertebrate habitat (Waters 1995, pp. 65-
68). Crayfish bioturbation (the mobilizing of sediments by crayfish
activity) can impact lakes, ponds, and wetlands, but it is not likely
to significantly affect high-gradient streams, such as the sites where
Redrock stoneflies are present, because the small amounts of suspended
sediment would be carried by stream flow through the water column until
they are deposited downstream at lower gradient and lower velocity
sites.
In some situations, crayfish bioturbation may actually improve
macroinvertebrate habitat in the stream environment by removing fine
sediments from interstitial spaces. For example, Statzner et al. (2000,
p. 1039) observed that crayfish bioturbation removed fine sediments and
benefited gravel-spawning salmonids. Also, Creed and Reed (2004, p.
234) found that mayfly (Ephemeroptera) numbers increased when crayfish
bioturbation removed fine sediments from gravel streambeds in Maryland.
This may be particularly important for the recovery of stream bottom
habitats after silt deposition following floods or other upstream
disturbances (Parkyn et al. 1997, p. 689). The Redrock stonefly sites
are stable stream channels that are moderately steep and dominated by
cobbles. These sites usually have little soft or fine sediments to be
disturbed and enter the water column. Therefore, crayfish bioturbation
is not likely to impact Redrock stoneflies.
In summary, we considered three mechanisms by which nonnative
crayfish could alter the habitat of the Redrock stonefly: (1)
Increasing leaf litter decomposition rates; (2) feeding on aquatic
plants; and (3) increasing turbidity and sedimentation from
bioturbation when crayfish are physically moving through fine
substrates. Our analysis of the biology of the stonefly and known
ecology of the crayfish finds that crayfish are not likely a
significant threat to the Redrock stonefly or its habitat.
Wildfires
Wildfires, through alterations of the terrestrial environment, can
cause many physical disturbances to streams (Gresswell 1999, p. 194).
Low-intensity fire, which is cooler burning and does not result in
major changes in the vegetation community in which it occurs, has been
a natural disturbance factor in forested landscapes for centuries, and
low-intensity fires were common in Southwestern forests and grasslands
prior to European settlement (Harrington and Sackett 1990, p. 122).
Fire suppression and wildfire control during the past decades have
changed this natural fire regime, resulting in unnatural fuel build-up
by increased understory vegetation and stand density of large trees,
which increases fire severity (Harrington and Sackett 1990, p. 122;
Schoennagel et al. 2004, p. 661; Westerling et al. 2006, p. 940). This
increased wildfire severity can result in large increases in the
magnitude and frequency of floods resulting from vegetation removal by
fire that did not likely occur prior to wildfire suppression and
control efforts (Neary et al. 2003, p. 30). Moody and Martin (2001, p.
2990) and Viera et al. (2004, p. 1254) each noted increased soil
erodibility and reduced infiltration after severe fires, which resulted
in dramatic increases in peak flow and sediment load in streams
draining burned catchments. In Southwestern montane watersheds, flood
events may occur during the July-August monsoon period immediately
following the May-June fire season (Rinne 1996, p. 653).
Wildfires have occurred in the past within watersheds that contain
the Redrock stonefly sites (for example, the Picture Fire above Spring
Creek, the Brady Fire above Wet Beaver Creek, and the Brins Fire and
Division Fire above Oak Creek). The Brady Fire burned approximately
4,000 acres (ac) (1,620 hectares (ha)) in the upper Wet Beaver Creek
watershed in 2009 (U.S. Forest Service 2010b, p. 1). Two USGS stream
gages are near the Oak Creek and Wet Beaver Creek Redrock stonefly
sites. Wet Beaver Creek stream flow data do not show that there has
been a significantly higher peak flow event after the fire. The nearest
Oak Creek stream gage, immediately upstream of Page Springs, began
functioning in October 1981. The Division Fire burned approximately 650
ac (260 ha) on the slopes above Oak Creek at Page Springs in August
1980, and the Brins Fire burned 4,317 ac (1,744 ha) north of Sedona in
June 2006 (U.S. Forest Service 2010b, p. 1). The USGS stream flow data
do not show any significantly higher peak flows after the two fires
(USGS 2010).
The direct effects of fire on stream macroinvertebrate communities
generally are minor or indiscernible (Rinne 1996, p. 655; Minshall et
al. 1997, p. 2519; Minshall 2003, p. 155). However, important
exceptions may include intense heating in areas of small water volume
(for example, small first-
[[Page 46258]]
or second-order streams or shallow, sluggish margins of larger streams)
and extended exposure to toxins from dense smoke and errant retardant
drops (Minshall 2003, p. 156). Redrock stoneflies may only experience
limited exposure to these effects in the swifter flowing water they
inhabit. Toxins and heated water may be transported through their
habitat before cumulative adverse effects result.
Instead, adverse effects of wildfire on stream macroinvertebrates
are largely the result of physical changes in habitat due to increased
runoff after the fire (Minshall et al. 1989, p. 712). This higher
runoff can scour, transport, and redistribute sediments and organic
matter, and it can restructure the physical stream environment (Herbst
and Cooper 2010, p. 1355). Aquatic macroinvertebrates are somewhat
resilient to flood events. High numbers may be removed after floods,
but their numbers quickly recover (Molles 1985, p. 281; Hering et al.
2004, p. 454). However, aquatic macroinvertebrates showed low
resistance and resilience to the effects of repeated, large, post-fire
flood events (Viera et al. 2004, p. 1253). Macroinvertebrate taxa
richness and densities in general were reduced after the first large
post-fire flood events, then recovered until the next large flood event
(Viera et al. 2004, pp. 1247-1248). In one example, a 3-year study from
central Arizona, Rinne (1996, p. 655) found large flood events reduced
macroinvertebrate densities by 85 to 90 percent after the Dude Fire.
Primary consumers, organisms that feed on plants, such as blackfly
and midge larvae (Diptera), and Baetid mayflies, quickly recolonized
and dominated the community after wildfire (Minshall et al. 1997, p.
2523; Viera et al. 2004, p. 1255). Many of these primary consumers are
filter feeders, which are able to take advantage of increased organic
matter entering the stream after a fire (Minshall et al. 1989, p. 713;
Herbst and Cooper 2010, p. 1363). They also disperse easily from
upstream areas through drift (Minshall et al. 1997, p. 2523) or from
adult dispersal from adjacent undisturbed habitats (Hughes et al. 2003,
p. 2151). Because of the increased availability of prey species
(primary consumers), large stonefly nymphs and other predatory
macroinvertebrates can dramatically increase in abundance after a fire
(Viera et al. 2004, pp. 1253-1254; Herbst and Cooper 2010, p. 1360;
Malison and Baxter 2010, p. 1335). For example, Viera et al. (2004, p.
1251) found the predaceous stonefly, Isoperla (Perlodidae), had
recovered in the first post-fire year that did not experience a
significant flood event. We would, therefore, anticipate that under
most circumstances, if fires resulted in a decrease in the availability
of primary consumer prey species for food of Redrock stoneflies, such
an effect would be short-term in nature.
Because of the limited exposure of the species to the effects of
wildfires and the expected resiliency of the species to recover
following any short-term habitat alteration resulting from wildfires,
we find the wildfires are not a significant threat to the Redrock
stonefly or its habitat.
Prescribed Fires
To avoid the detrimental effects of large, high-severity fires and
to restore more natural fire disturbance patterns in forest ecosystems
of the western United States, prescribed fires and mechanical forest
thinnings (selected removal of trees) are being used as management
tools, particularly near wildland-urban interfaces (Arkle and Pilliod
2010, p. 893). Prescribed fires are often intentionally excluded from,
or near, riparian forests to avoid fire-associated increases in
sediment levels and other habitat changes that could be detrimental to
ecologically sensitive habitats and aquatic taxa (Arkle and Pillirod
2010, pp. 893-894). Therefore, prescribed fires in Arizona are usually
designed to avoid impacting riparian and stream habitats. For example,
the U.S. Forest Service has formally consulted with the Service under
section 7 of the Act on two prescribed fires that they determined would
have an adverse effect on two listed species, Gila topminnow
(Poeciliopsis occidentalis) and loach minnow (Tiaroga cobitis), in a
riparian or stream community in Arizona: the Quien Sabe Fire Management
Treatment (Service 1991, pp. 8-9) and the Robinson Mesa Prescribed Fire
Project (Service 1999, pp. 22-23). Both consultations included
mandatory terms and conditions to reduce the adverse effects of project
implementation to listed species. We anticipate that the exclusion of
prescribed fire from riparian areas, along with conservation measures
put in place during prescribed fire planning for other species, is
adequate to minimize impacts to the Redrock stonefly. The Redrock
stonefly's resilience to wildfire, discussed above, would also reduce
the effects of prescribed fire. Therefore, we find that prescribed
fires are not a significant threat to the Redrock stonefly or its
habitat.
Recreation
The Redrock stonefly sites or their watersheds occur on private,
State, and Federal lands. The Federal lands are managed for recreation
and other purposes, and some level of recreation occurs on every stream
occupied by the Redrock stonefly. A study of outdoor recreation trends
in the United States found increases in participation in most of the
activities surveyed, which included bicycling, primitive or developed-
area camping, bird watching, hiking, backpacking, and snowmobiling
(Cordell et al. 1999, pp. 221-321). Human population growth trends are
expected to continue into the future throughout the Southwest, leading
to higher demand for outdoor recreational opportunities. In the arid
Southwest, the human desire to recreate in or near water, and the
relative scarcity of such recreational opportunities, tends to focus
recreation impacts on riparian areas (Winter 1993, p. 155; Briggs 1996,
p. 36).
Streams are popular hiking destinations in Arizona. While there are
hiking opportunities at each of the Redrock stonefly sites, actual use
is limited by their location in remote rugged canyons with poor access
or due to land ownership restrictions (State and private lands). Spring
Creek and the three lower Tonto Creek sites are located in areas
without easy road access. The upper Tonto Creek site is difficult to
access because of private land downstream of its location. The Campbell
Blue Creek site is located along a forest road, leading to a private
ranch in a remote area in eastern Arizona. The Redrock stonefly is not
affected by hiking in Oak Creek. The Page Springs Oak Creek site, at
the Page Springs Hatchery, has hiking trails on the adjacent uplands.
The AGFD allows very limited creek access from their property, due to
concerns of fish disease transmission from the creek to the hatchery.
Redrock State Park only allows visitor access along designated trails;
swimming or wading is prohibited in Oak Creek. The Beaver Creek Ranch
is a private high school that limits public access to the east side of
the creek. Recreational use is primarily hiking through the area along
the west side of the creek.
Hiking in streams can be a source of disturbance to stream
invertebrates. Aquatic invertebrates can be induced to drift as a
result of disturbance by hikers within the stream. In one study,
increased numbers of hikers resulted in increased densities of drifting
aquatic invertebrates (Caires et al. 2010, p. 555). However, this is
not likely to be a significant effect, because aquatic invertebrates
are adapted to flash floods, which cause a similar, but larger,
disturbance (Caires et al. 2010, p. 555).
[[Page 46259]]
Caires et al. (2010, p. 555) found that aquatic invertebrates areas
disturbed by hikers quickly recolonized from upstream. Redrock
stoneflies do not intentionally drift, but if hiking causes then to
enter the water column, they would be susceptible to fish predation
until they settled back down to the stream bed. Future flood events
could carry Redrock stoneflies downstream to unoccupied habitats.
Because of the limited opportunity for hikers in streams occupied by
the Redrock stonefly and the likely, but short-term, effects of hiking,
this type of recreational activity is not a significant threat to the
Redrock stonefly or its habitat.
Off-road vehicle (ORV) use is another form of recreation that can
increase sedimentation in streams by damaging riparian vegetation and
stream banks. However, most Redrock stonefly sites are either
inaccessible or minimally impacted by ORV use. The Oak Creek sites are
not accessible to ORV use. The Page Springs site, at the Page Springs
Fish Hatchery, limits visitors to walking trails on both sides of Oak
Creek, fish hatchery tours, and fishing. Also, ORV use is prohibited at
the Redrock Crossing site at Red State Park. The Wet Beaver Creek sites
are inaccessible to ORVs because the U.S. Forest Service road leading
to the site upstream of the USGS gage is closed to all vehicular
traffic. The lower Wet Beaver Creek site, near the Beaver Creek Ranch,
is protected by private land on the east side and the closed U.S.
Forest Service road on the west side. Similarly, the three Tonto Creek
sites are either located in a narrow canyon or have private land at
Bear Flats that blocks access. The lower site is located in the Hells
Gate Wilderness, where mechanized and motorized vehicle uses are
prohibited. The Spring Creek site is located in a steep-walled canyon
without any road access. The Campbell Blue Creek site is the only
habitat that may experience some ORV use because there is a road
paralleling the creek that provides vehicle access into the area.
Therefore, due to the lack of access to all but one of the known
occupied sites, we do not consider ORV use a threat to the Redrock
stonefly or its habitat.
In summary, we considered the potential impacts to Redrock stonefly
habitat from recreational activities primarily associated with hiking
and ORV use. We found there is limited access to Redrock stonefly
habitats for these activities and very minor effects when they occur.
Therefore, we find that recreation is not a significant threat to the
Redrock stonefly or its habitat.
Urban and Rural Development
The effects of urban and rural development on natural habitats are
expected to increase as human populations increase. Consumer interest
in second home and retirement real estate investments has increased
significantly in recent times within the southwestern United States.
Medina (1990, p. 351) points out that many real estate investors are
looking for scenic areas with mild climates to develop properties that
are within, or adjacent to, riparian areas, due to their aesthetic
appeal and available water, especially in the southwestern United
States. Arizona's population increased by 28 percent from 2000 to 2009
(U.S. Census Bureau 2010, p. 1). Over the same time period, population
increases in the Arizona counties where Redrock stoneflies occur are as
follows: Yavapai County (28 percent); Gila County (1.8 percent); and
Apache County (1.8 percent) (U.S. Census Bureau 2010, p. 1).
Increased urbanization and population growth results in increased
demands for water development projects. Collier et al. (1996, p. 16)
mentions that water development projects are one of two main causes of
decline of native fish in the Salt and Gila Rivers of Arizona, and
municipal water use in central Arizona increased by 39 percent over 8
years (American Rivers 2006, p. 1). Water for development and
urbanization is often supplied by groundwater pumping and surface water
diversions from sources that include reservoirs and the Central Arizona
Project's allocations from the Colorado River. The hydrologic
connection between groundwater and surface flow of intermittent and
perennial streams is becoming better understood as a result of new
research. Groundwater pumping creates a cone of depression within the
affected aquifer that slowly extends outward from the well site. When
the cone of depression intersects the hyporheic zone of a stream (the
transition zone between surface water and groundwater), the surface
water flow may decrease, and the subsequent drying of riparian and
wetland vegetative communities may result (Webb and Leake 2006, p.
308).
Streamflow reduction from increased groundwater use and surface
water diversion can have a dramatic impact on stream habitat and
associated macroinvertebrate communities. Artificial flow reductions
frequently lead to negative changes in aquatic ecosystems, such as
decreased water depth, increased sedimentation, and altered water
temperatures and chemistry; all of these can reduce or influence
macroinvertebrate numbers, richness, competition, predation, and other
interactions (Dewson et al. 2007, pp. 401-411). Twenter and Metzger
(1963, p. 29) determined that permeable sandstone beds are the primary
source of water for springs in the Page Springs (also referred to as
Cave Springs) and Spring Creek areas, and much of the perennial flow in
Oak Creek is from these springs. Twenter and Metzger (1963, p. 14)
determined that the average base flow of Oak Creek just above the
springs complex during winter months was 40 cfs (1.13 cms). After
adding the 36 cfs (1.01 cms) inflow from springs and 16 cfs (0.45 cms)
from Spring Creek, the base flow increased to 92 cfs (2.6 cms) near the
mouth of the creek. There are six springs, not including Page Springs,
immediately upstream of the Page Springs Redrock stonefly site that
produces more than 10 gpm (37.8 lpm) (ADWR 2009a, p. 268). Page Springs
is the second highest discharging spring in the Verde River watershed,
flowing at 29 cfs (0.82 cms) (Flora 2004, p. 38). These springs and
seeps in the Page Springs area provide a large volume of water to Oak
Creek, where the Redrock stonefly occurs (Mitchell 2001, p. 4). An
analysis of the Page Springs flow rate between January 1, 1996, and
February 9, 2000, detected a 15 percent decline in flow (Mitchell 2001,
p. 5). This analysis period coincided with a severe to extreme drought,
and with the drilling of three new wells upstream of Page Springs
(Mitchell 2001, p. 6). The ADWR's records show that three wells have
been drilled in close proximity and up gradient of Cave Springs
(Mitchell 2001, p. 6). Two of these wells pump between 1,200 gpm (4,542
lpm) and 1,500 gpm (5,678 lpm), and are within 0.75 mi (1.2 km) of Page
Springs. Given their proximity, production rate, and hydrological
connectivity, groundwater withdrawal by these wells could have a direct
impact on flow at Page Springs (Mitchell 2001, p. 6). However, the
extent of the impact of these wells on the spring cannot be determined
without long-term aquifer tests and simultaneous discharge monitoring
at Cave Springs (Mitchell 2001, p. 6).
Wet Beaver Creek, upstream of the USGS stream gage, is not affected
by diversions or wells, because the watershed above this site is on the
Coconino National Forest. The Beaver Creek Ranch, adjacent to the lower
Wet Beaver Creek site, has a small pond that is filled by a diversion
from the creek. This pond is not large enough to impact
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Wet Beaver Creek base flow (Hedwall 2011, p. 1).
The Upper Tonto Creek headwaters are fed by numerous springs, the
largest of which is Tonto Springs. Long-term flow records from Tonto
Springs show little fluctuation in baseflow over a 20-year period
(Parker et al. 2005, p. 73). There are numerous small wells located on
private lands and at U.S. Forest Service campgrounds upstream of the
Redrock stonefly site. The ADWR (2009a, p. 187) does not monitor water
depth in these wells, nor address the wells' impact to Tonto Creek
baseflow.
The Redrock stonefly site on Spring Creek is not affected by
groundwater wells as ADWR does not identify any wells in the vicinity
(2009a, p. 197). The Campbell Blue Creek Redrock stonefly site is
located in an undeveloped watershed with only two small parcels of
private land upstream of two ADWR-registered wells at the Blue River
Ranch. There