Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Platte River Caddisfly as Endangered or Threatened, 52650-52673 [2012-21352]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 77, Number 169 (Thursday, August 30, 2012)]
[Proposed Rules]
[Pages 52650-52673]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-21352]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R6-ES-2012-0040; 4500030113]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Platte River Caddisfly as Endangered or 
Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the Platte River caddisfly 
(Ironoquia plattensis) as an endangered or threatened species 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 Platte River caddisfly as an 
endangered or threatened species 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 Platte River caddisfly 
or its habitat at any time.

DATES: The finding announced in this document was made on August 30, 
2012.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R6-ES-2012-0040. 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, Nebraska Field

[[Page 52651]]

Office, Federal Building, 2nd Floor, 203 West 2nd Street, Grand Island, 
NE 68801. Please submit any new information, materials, comments, or 
questions concerning this finding to the above street address.

FOR FURTHER INFORMATION CONTACT: Michael D. George, Field Supervisor, 
Nebraska Field Office (see ADDRESSES); by telephone (308-382-6468, 
extension 12); or by facsimile (308-384-8835). mail to: Persons who use 
a telecommunications device for the deaf (TDD) may 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 Endangered and Threatened Wildlife and 
Plants that contains substantial scientific or commercial information 
that listing a 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 either an endangered or 
threatened species, 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 July 30, 2007, we received a petition dated July 24, 2007, from 
Forest Guardians (now WildEarth Guardians), requesting that 206 species 
in the Mountain-Prairie Region, including the Platte River caddisfly, 
be listed as an endangered or threatened species under the Act, and 
critical habitat be designated. Included in the petition were analyses, 
references, and documentation provided by NatureServe in its online 
database at https://www.natureserve.org/. We acknowledged receipt of the 
petition in a letter to the petitioners, dated August 24, 2007, and 
stated that, based on preliminary review, we found no compelling 
evidence to support an emergency listing for any of the species covered 
by the petition. In that letter we also stated that we would begin to 
assess the information provided in the petition in October 2007.
    We published a partial 90-day finding for 38 of the petition's 206 
species in the Federal Register (74 FR 41649) on August 18, 2009; the 
Platte River caddisfly was one of 29 species for which we found there 
was substantial information indicating that listing may be warranted 
under the Act. In that document, we announced that we were initiating a 
status review. On January 12, 2010, WildEarth Guardians filed a 
complaint indicating that the Service failed to comply with the 
statutory deadline to complete a 12-month finding for the Platte River 
caddisfly. This complaint was consolidated with several others, and a 
multi-district settlement agreement with WildEarth Guardians was 
approved on September 9, 2011, which included an agreement that the 
Service would complete the 12-month finding for the Platte River 
caddisfly by the end of Fiscal Year 2012. Funding for completing the 
12-month finding became available in Fiscal Year 2011, and we began 
work at that time. This notice constitutes the 12-month finding on the 
July 24, 2007, petition to list the Platte River caddisfly as an 
endangered or threatened species.

Species Information

Species Description
    The Platte River caddisfly (Ironoquia plattensis) adult is a small, 
brown, moth-like insect with a body length of 5.5-6.5 millimeters (mm) 
(0.21-0.26 inches (in)) and forewing length of 6.5-8.0 mm (0.26-0.31 
in) (Alexander and Whiles 2000, p. 2). Wing membranes and veins are 
light or iridescent brown with white spotting (Alexander and Whiles 
2000, p. 2). The Platte River caddisfly has a short proboscis (tubular 
mouthpart used for feeding) and long antennae, similar to other species 
of caddisflies (Holzenthal et al. 2007, p. 648). Platte River caddisfly 
adults can be distinguished from those of other species in the 
Ironoquia genus by their much smaller size (forewing length of 6.5-8.0 
mm (0.26-0.31 in) in Platte River caddisflies contrasting with >14 mm 
(0.55 in) in most other Ironoquia species) (Alexander and Whiles 2000, 
p. 2).
    Like several caddisfly species, Platte River caddisfly larvae 
construct a case around the abdomen (Mackay and Wiggins 1979, p. 186). 
All caddisflies produce silk from modified salivary glands, and case-
making caddisfly larvae use this silk to fuse together organic or 
mineral material from the surrounding environment (Mackay and Wiggins 
1979, pp. 185-186; Holzenthal et al. 2007, p. 644). Cases are generally 
thought to protect larvae by providing camouflage against predation or 
resistance to crushing (Mackay and Wiggins 1979, p. 200; Otto and 
Svensson 1980, p. 855). The Platte River caddisfly case is composed of 
sand grains and can be up to 16.0 mm (0.63 in) long, while larvae can 
attain sizes up to 14.0 mm (0.55 in) in length (Vivian 2010, pers. 
obs.).
    Platte River caddisfly larvae have a light brown head and thorax 
and a yellowish to whitish abdomen (Vivian 2010, pers. obs.), much like 
the larvae of Ironoquia parvula (no common name) (Flint 1958, p. 59). 
Larvae in the Ironoquia genus can be distinguished from larvae in other 
caddisfly genera by four morphological characteristics that are 
distinguishable under a microscope (Flint 1958, p. 59; Wiggins 1977, p. 
248). Differences in larval size (Alexander and Whiles 2000, p. 1) and 
case material among species have also been noted (Wiggins 1977, p. 
248).
Taxonomy
    The Platte River caddisfly was formally described as a new species 
in the order Trichoptera (caddisflies) in 2000 by Alexander and Whiles 
(2000, p. 2). The Platte River caddisfly is in the family 
Limnephilidae, or the northern caddisflies, subfamily Dicosmoceniae, 
and genus Ironoquia (Wiggins 1977, p. 181; Alexander and Whiles 2000, 
p. 1).
    The caddisfly family Limnephilidae is considered to be the most 
ecologically diverse family of Trichoptera (Holzenthal et al. 2007, p. 
674) and is the largest caddisfly family in North America, with over 
900 species in more than 100 genera (Holzenthal et al. 2007, p. 674). 
The Limnephilidae family is dominant at higher latitudes and 
elevations, has the widest distribution of any caddisfly family, and 
comprises one-third of all Nearctic (ecozone comprising Arctic and 
temperate areas of North America and Greenland) caddisfly species 
(Wiggins 1977, p. 179). Caddisflies in this family may be collected 
from springs, pools, seeps, marshes, bogs, fens, streams, rivers, and 
lakes (Wiggins 1977, p. 179). Limnephilids largely feed on larger bits 
of plant material, such as fallen leaves, or organic materials that 
form atop rock surfaces (Wiggins 1977, p. 179).
    The Ironoquia genus belongs to the subfamily Dicosmoceniae, which 
mostly occurs in cool, lotic (running water) environments, except for 
Ironoquia, which occurs in temporary pools (Flint

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1958, p. 59; Wiggins 1977, p. 248). The genus Ironoquia is comprised of 
six species: the Platte River caddisfly (I. plattensis), I. 
punctatissima (no common name) (Walker 1852), I. parvula (no common 
name) (Flint 1958), I. dubia (no common name) (Stephens 1837), I. 
lyrata (no common name) (Ross 1938), and I. kaskaskia (no common name) 
(Ross 1944), with the Platte River caddisfly being the most recently 
described (Encyclopedia of Life 2011, entire). All of these species 
except I. dubia (Europe) occur only in North America (Williams and 
Williams 1975, p. 829; [Cacute]uk and Vu[ccaron]kovi[cacute] 2010, pp. 
232, 234).
    Ironoquia is the only genus within the Dicosmoceniae subfamily that 
occurs in temporary waters (Wiggins 1977, p. 248). In North America, 
Ironoquia is mostly found throughout the central and eastern portions 
of the United States (Wiggins 1977, p. 248) and is most often collected 
from temporary pools or wetlands but can also occur in perennial waters 
(Flint 1958, p. 61; [Cacute]uk and Vu[ccaron]kovi[cacute] 2010, p. 
234). The Platte River caddisfly has been found to co-occur with I. 
punctatissima, which is a common species on the Great Plains, but I. 
punctatissima is morphologically distinct and much larger than the 
Platte River caddisfly (Alexander and Whiles 2000, p. 1; Geluso et al. 
2011, p. 1024).
    The Platte River caddisfly is thought to be most closely related to 
I. parvula (Alexander and Whiles 2000, p. 1), which occurs in Ohio and 
the northeastern United States (Flint 1958, p. 59; Wiggins 1977, p. 
248; Swegman et al. 1981, p. 141; Garono and MacLean 1988, p. 148). 
Platte River caddisfly adults are smaller and have lighter color and 
more pronounced spotting on the wings than I. parvula (Alexander and 
Whiles 2000, p. 2). We find that Alexander and Whiles (2000, entire) 
provide the best available information on the taxonomy of the Platte 
River caddisfly, and no other challenges to the taxonomy have been 
raised since the Platte River caddisfly was described. Therefore, we 
consider the Platte River caddisfly a valid species for listing under 
the Act.
Habitat Description
    The Platte River caddisfly was discovered in 1997, in a warm-water 
slough (backwater area or marsh that is groundwater fed) in south-
central Nebraska along the Platte River on Mormon Island (hereafter 
type locality), which is land owned by the Platte River Whooping Crane 
Maintenance Trust (hereafter Crane Trust (a conservation organization)) 
southwest of Grand Island, Nebraska (Whiles et al. 1999, p. 534; 
Goldowitz 2012, pers. comm.). This slough had an intermittent 
hydroperiod (duration of inundation) and held water 75-90 percent of 
the time or about 275-330 days out of the year (Whiles et al. 1999, p. 
534; Goldowitz 2004, pp. 2-3). The area lacked trees (Whiles et al. 
1999, p. 534) and was located within the largest remaining tract of 
native prairie in the Central Platte Valley (Goldowitz 2004, p. 2).
    Intermittent wetlands, such as the type locality, have been 
described as any water body that holds water for about 8 to 10 months 
during the year (Wiggins et al. 1980, p. 100); some intermittent sites 
may or may not completely dry in a year (Tarr and Babbitt 2007, p. 6). 
These wetlands differ from ephemeral wetlands (that hold water for a 
relatively short period of time (e.g., 4 months)) and permanent 
wetlands (rarely dry) (Tarr and Babbit 2007, p. 6). Intermittent 
wetlands dry when the groundwater table drops below the ground surface.
    Since the Platte River caddisfly was discovered, surveys have 
mostly found the caddisfly in sloughs with intermittent hydroperiods; 
however, the caddisfly has also been found in sloughs with permanent 
hydroperiods (Goldowitz 2004, p. 5; Meyer and Whiles 2008, p. 632; 
Vivian 2010, p. 54; Geluso et al. 2011, p. 1024). In sloughs with 
permanent hydroperiods, the caddisfly has been observed in lower 
numbers, which is true of other Ironoquia species, likely because of 
the presence of more predators in permanent waters (Wiggins et al. 
1980, p. 148; Vivian 2010, p. 54). The caddisfly has not been observed 
in ephemeral wetlands (Vivian 2009, pers. obs.).
    In general, the intermittent wetlands where the caddisfly occurs 
are found along the floodplains of the Platte, Loup, and Elkhorn Rivers 
in central Nebraska (LaGrange 2004, p. 15) and are shallow, linear 
depressions that are historical channel remnants of these river systems 
(Friesen et al. 2000, p. 4-8). The presence of water in these sloughs 
is influenced by groundwater levels and trapped surface run-in (Friesen 
et al. 2000, p. 4-8). Groundwater levels are controlled by river stage 
(flows), precipitation, and evapotranspiration (Wesche et al. 1994, p, 
iii). Platte River flows are principally tied to snowmelt from the 
Rocky Mountains and local precipitation events (Simons and Associates 
2000, pp. 2-5), while Loup River and Elkhorn River flows are tied to 
the Ogallala Aquifer (Peterson et al. 2008, p. 5). Sloughs that support 
the caddisfly vary in their distance to the main river channel. Most 
sloughs are adjacent to the main channel, while some occur in areas 
more than 0.4 kilometers (km) (0.25 miles (mi)) away.
    Sloughs with the Platte River caddisfly are typically described as 
lentic (with little to no flow) (Whiles et al. 1999, p. 533; Alexander 
and Whiles 2000, p. 2). However, two sites do contain some flow, and 
the caddisfly appears to occur in higher densities in areas with 
flowing water than in stagnant areas (Harner 2012, pers. comm.). 
Because of their groundwater connection, sloughs with the caddisfly may 
maintain thick ice cover on surface waters through the winter without 
completely freezing to the bottom (Whiles et al. 1999, p. 534; 
Goldowitz 2004, p. 2). Slough substrata often consist of a thick layer 
of detritus and silt overlying sand (Whiles et al. 1999, p. 534; 
Alexander and Whiles 2000, p. 6). Soils in the sloughs consist of a 
mixture of loam, sand, and gravelly sand and tend to be frequently 
flooded and poorly drained (Natural Resources Conservation Service 
(NRCS) Web Soil Survey 2009, entire).
    Because it is an inhabitant of intermittent waters, the Platte 
River caddisfly is tolerant of large fluctuations in water chemistry 
(Williams 1996, p. 634; Whiles et al. 1999, p. 534). Large variations 
in water quality (e.g., pH, conductivity, total dissolved solids, 
dissolved oxygen, turbidity, and temperature) have been observed among 
five forested sites where the caddisfly occurs (Vivian 2010, pp. 81, 
96). Furthermore, average conductivity and pH in sloughs with the 
caddisfly reported by Vivian (2010, pp. 81, 96) differed from the 
average values reported by Whiles et al. (1999, p. 534) and Geluso et 
al. (2011, p. 1022). The gradient of water chemistry observed between 
forested sloughs and the type locality is likely a result of the 
differences in habitat types, and demonstrates that the Platte River 
caddisfly can withstand a broad range of water quality.
    Vegetation in sloughs occupied by the caddisfly is typical wetland 
flora, such as Typha spp. (cattails), Schoenoplectus fluviatilis (river 
bulrush), Eleocharis spp. and Cyperus spp. (sedges), and Lemna spp. 
(duckweed); some sloughs support nonnative, invasive vegetation, 
including Phalaris arundinacea (reed canarygrass), Phragmites (common 
reed), and Lythrum salicaria (purple loosestrife). Plant species along 
slough banks and margins include woody species, such as Fraxinus 
pennsylvanica (green ash) and Populus deltoides (cottonwood), and grass 
species, such as Spartina pectinata (prairie cordgrass)

[[Page 52653]]

and smooth brome (Bromus inermis, invasive). Various forbs are also 
present throughout the slough. Most areas where the Platte River 
caddisfly has been observed since it was described have an abundance of 
woody vegetation, which contrasts with the treeless, wet meadow 
environment encountered at the type locality and one other population 
at the Crane Trust (Whiles et al. 1999, p. 534; Vivian 2010, p. 56; 
Vivian 2011, pp. 33-35). Overall, the Platte River caddisfly is 
tolerant of a range of conditions, including variations in hydroperiod, 
water quality, and vegetation, but thrives in intermittent sloughs.
Life History and Ecology
    The Platte River caddisfly lifecycle was characterized by Whiles et 
al. (1999, entire). The caddisfly is univoltine (one generation per 
year). The adult flight period for the Platte River caddisfly is 
between late September and mid-October. Adults first emerge around 
late-September and live for about 7 to 10 days, with the entire 
emergence period lasting 3 to 4 weeks. While active, adults oviposit 
(lay eggs) on the surface film of the water, the eggs sink to the 
bottom of the slough, and larvae hatch as first instars (life stage 
between molts) sometime in November. Aquatic larvae overwinter in the 
slough as first instars. In late winter, larvae construct their case 
(Vivian 2010, pers. obs.) and begin feeding and growing rapidly and 
proceed through four more instars. Between late April and early June, 
fifth (final) instars climb upslope from the water and aestivate (pass 
stressful time periods in a dormant condition) during the summer months 
when it is typically dry along the adjacent slough banks (Whiles et al. 
1999, pp. 535-536; Geluso et al. 2011, p. 1023). Platte River caddisfly 
larvae eventually pupate (metamorphose between larva and adult) along 
slough margins in the larval case. Pupation lasts about 4 weeks until 
adult emergence in late September.
    While in its aquatic stage, the Platte River caddisfly is 
considered a shredder and largely feeds upon senescent (aged) plant 
tissue (Whiles et al. 1999, pp. 542-543). As one of the few shredders 
present in sloughs, the Platte River caddisfly plays an important role 
in the decomposition of organic matter in these systems (Whiles et al. 
1999, pp. 539, 543). In its terrestrial stage, the Platte River 
caddisfly does not feed (Whiles et al. 1999, p. 537), and as an adult, 
the species has the ability to ingest liquids (Holzenthal et al. 2007, 
p. 648).
    The Platte River caddisfly likely has a lifecycle adapted to the 
intermittent wetlands found along the Platte, Loup, and Elkhorn River 
systems (Whiles et al. 1999, p. 537; Vivian 2010, pers. obs.). For 
example, larval emigration to adjacent mesic grassland habitat and 
adult emergence were found to coincide with early summer drying and 
fall inundation of the wetlands, respectively (Whiles et al. 1999, pp. 
537, 542). The Platte River caddisfly is dependent upon water for the 
egg and larval stages of its lifecycle, (e.g., for at least 7 to 8 
months out of the year) (Whiles et al. 1999, pp. 537-539).
    While most caddisflies have an entirely aquatic larval phase, all 
Ironoquia species are known to aestivate in leaf litter near the 
receding water line during the summer months prior to pupating (Flint 
1958, p. 61; Williams and Williams 1975, p. 830; Wiggins 1977, p. 248; 
Johansson and Nilsson 1994, p. 21; Whiles et al. 1999, p. 534). 
However, some aestivating Platte River caddisfly larvae have been found 
to burrow beneath the ground surface (Geluso et al. 2011, p. 1024). 
This behavior may be a way to withstand summer drying of sloughs or to 
avoid desiccation, as reported for other caddisflies (Mackay and 
Wiggins 1979, p. 187; Wiggins et al. 1980, p. 179; Johannson and 
Nilsson 1994, p. 21; Geluso et al. 2011, p. 1024), as soil temperatures 
in unshaded areas can reach 54 degrees Celsius ([deg]C) (129 degrees 
Fahrenheit ([deg]F)) in the summer (Vivian 2010, pers. obs.). This 
behavior could protect aestivating larvae against late spring (May-
June) flows, which are characteristic of the Platte River system and 
could scour (wash) larvae downstream (Simon and Associates 2000, p. 8) 
and other disturbances characteristic of the Great Plains ecosystem, 
such as livestock grazing (Geluso et al. 2011, p. 1024).
Historical Range and Distribution
    Data collection on the range of the Platte River caddisfly began in 
1999, shortly after it was discovered, and continued in 2004 (Goldowitz 
2004, p. 3). Surveys were conducted at 48 locations along the Platte 
and Loup Rivers, and the Platte River caddisfly was found at 9 of these 
sites (Goldowitz 2004, p. 5). These populations occupied an 
approximately 100-km (60-mi) stretch of the central Platte River that 
extends from south of Gibbon, Nebraska (Kearney County), to Central 
City, Nebraska (Merrick County). Surveys for the caddisfly on the Loup 
River were negative (Goldowitz 2004, p. 9). Monitoring efforts in 2004 
did not find the caddisfly at the type locality, despite a consistent 
adult emergence pattern in the preceding 7 years and the species' prior 
abundance at that site (Goldowitz 2004, p. 8). Because of its apparent 
rarity, the caddisfly was designated a Tier 1 species in Nebraska as 
per the State's natural legacy plan (Schneider et al. 2005, p. 93). 
Tier 1 species are those that are at risk of extinction on a global 
scale or at risk of becoming extirpated from Nebraska (Schneider et al. 
2005, p. 17).
Current Range and Distribution
    Through 2004, the Platte River caddisfly was only known from the 
Platte River (Goldowitz 2004, p. 9). However, surveys for new Platte 
River caddisfly populations resulted in the discovery of the species on 
the Loup and Elkhorn Rivers in Nebraska in 2009 and 2010 (Vivian 2010, 
p. 50). Close visual examination of adults and larvae at sites on the 
Loup and Elkhorn Rivers demonstrated that the species was not I. 
parvula and confirmed the presence of the Platte River caddisfly on 
these systems. However, because of the distance between some caddisfly 
populations on the Platte, Loup, and Elkhorn Rivers, we determined 
there was a need to identify potential genetic differences for the 
species among sites. Genetic analyses indicated that there is a low 
amount of gene flow among all three rivers, and that a population 
tested on the Elkhorn River was genetically divergent, but not 
different, from the populations on the Platte and Loup Rivers 
(Cavallaro et al. 2011, p. 7). This genetic divergence appears to be a 
product of geographic isolation as opposed to habitat fragmentation.
    The Platte River is formed at the confluence of the North Platte 
and South Platte Rivers in west-central Nebraska, just east of North 
Platte, and generally flows east until it meets the Missouri River 
along the eastern edge of Nebraska (Williams 1978, pp. 1-2). The North 
Platte River originates in the Rocky Mountains of Colorado, flows north 
through central Wyoming and then southeast into Nebraska (Williams 
1978, p. 1); the South Platte River originates in Colorado and flows 
northeast until it meets the Platte River at North Platte, Nebraska 
(Simons and Associates 2000, p. 2). Platte River flows are largely 
dependent upon snowmelt from the Rocky Mountains and local 
precipitation events (Simons and Associates 2000, pp. 2-5).
    The Loup and Elkhorn Rivers are tributaries of the Platte River 
system. The Loup River contains several tributaries, including the 
North Loup, Middle Loup, South Loup, and Cedar Rivers in Nebraska. The 
Loup River is

[[Page 52654]]

formed at the confluence of the Middle Loup and North Loup Rivers near 
St. Paul, Nebraska, and flows east until it meets the Platte River at 
Columbus, Nebraska, in the eastern third of the State. The Loup River 
drains groundwater from the Sandhills and the underlying Ogallala 
Aquifer, and its tributaries flow northwest to southeast, while the 
Loup flows east or northeast until it meets the Platte River (Peterson 
et al. 2008, pp. 2-5). The Elkhorn River drains wet meadows and plains 
in north-central Nebraska, and flows east-southeast until it meets the 
Platte River near Omaha, Nebraska (Peterson et al. 2008, pp. 2-5).
    In Nebraska, there is a gradient of precipitation from west to 
east. Just east of the Rocky Mountains in central Nebraska there is a 
predominant rain shadow effect that results in low amounts of 
precipitation in western Nebraska. Precipitation generally increases as 
one travels east towards Nebraska's eastern border (Simon and 
Associates 2000, p. 2).
    Surveys for the Platte River caddisfly between 2009 and 2011 
identified 35 caddisfly populations out of 115 sites visited, including 
5 of the 9 sites identified by Goldowitz (2004, entire) (Vivian 2010, 
p. 46; Geluso et al. 2011, entire; Figure 1 below). With these recent 
survey efforts, the caddisfly is now known from a 390-km (240-mi) 
stretch of the Platte River that runs from near Sutherland, Nebraska 
(Lincoln County), to near Schuyler, Nebraska (Platte County), and from 
the Loup and Elkhorn River systems (Figure 1 below). Within this range, 
there is approximately a 155-km (93-mi) gap in the distribution of the 
caddisfly between Hershey, Nebraska, and Elm Creek, Nebraska (Vivian 
2010, p. 51). Twenty-four surveys for the caddisfly were conducted in 
this gap, and the caddisfly was not found (Vivian 2010, p. 50).
[GRAPHIC] [TIFF OMITTED] TP30AU12.062

    From recent survey efforts, one site near Shelton, Nebraska, is 
presumed extirpated (Riens and Hoback 2008, p. 1; Vivian 2010, p. 48). 
Also, the Platte River caddisfly was observed at the type locality in 
2010 (Geluso et al. 2011, p. 1023), after not having been observed 
there during surveys in 2004 and 2007-2009 (Goldowitz 2004, p. 8; Riens 
and Hoback 2008, p. 1; Vivian 2010, p. 53). Survey work in 2009-2011 
also identified 13 sites along the Platte, Loup, Elkhorn, and Cedar 
Rivers that contained discarded larval cases but no live individuals 
(Vivian 2010, p. 46). Finding a site with a caddisfly case in a slough 
along the Cedar River indicates that the Platte River caddisfly is 
likely present in the basin. However, observing live individuals at a 
site is needed to confirm its presence there, because it is thought 
that discarded larval cases degrade slowly and could represent 
generations from previous years (Vivian 2010, pp. 49, 55-56).
    Aside from the Cedar River, it appears that more surveys for the 
Platte River caddisfly could result in the discovery of additional 
populations on other river drainages in Nebraska, including the 
Niobrara and Republican Rivers. More survey work on the Platte, Loup, 
and Elkhorn drainages would likely result in the discovery of new 
populations on these systems as well. Between 2009

[[Page 52655]]

and 2011, satellite imagery was used to identify potential caddisfly 
habitat throughout Nebraska prior to conducting surveys (Vivian 2010, 
p. 38). There are additional areas of remaining potential Platte River 
caddisfly habitat along Nebraska's major river systems that have yet to 
be surveyed (Vivian 2011, pers. obs.). Thus, ongoing surveys are likely 
to expand the known range of the Platte River caddisfly.
Population Densities
    At the type locality, the Platte River caddisfly was considered an 
abundant component of the slough ecosystem. In 1997-1998, an average of 
805  194 larvae per square meter (m\2\) was observed 
throughout the aquatic life stage of the caddisfly lifecycle, and 
410.67 larvae per m\2\ were present in the aquatic environment in May 
1998 (Whiles et al. 1999, pp. 537, 540). Geluso et al. (2011, p. 1022) 
reported a mean density of 553  284 Platte River caddisfly 
larvae per m\2\ (n = 19) from a site at the Crane Trust on Shoemaker 
Island (hereafter ``Wild Rose Slough''), which is located about 5 km 
(3.2 mi) upstream of the type locality. With the exception of these two 
sites, the Platte River caddisfly has been found to occur in lower 
densities (Whiles et al. 1999, pp. 539-540).
    In May of 2009 and 2010, aquatic larval densities were measured at 
18 sites with a Platte River caddisfly population on the Platte River 
only, and larval densities ranged from zero to 125.7 individuals per 
m\2\ (Vivian 2010, p. 64). Aestivating (terrestrial life stage) larval 
densities at 12 of 13 sites sampled ranged from zero to 116 individuals 
per m\2\ (Vivian 2010, p. 65). Day and nighttime sampling found 
anywhere between zero and eight adults per hour of observation (Vivian 
2010, pp. 65-66).
    The aquatic and terrestrial larval densities reported by Vivian 
(2010, pp. 40-41) are not directly comparable to Whiles et al. (1999, 
p. 535), because different methodologies were used, and a different 
volume of sediment was sampled during the aquatic sampling period 
(Meyer et al. 2011, p. 110). Meanwhile, Geluso et al. (2011, p. 1022) 
used the same aquatic sampling method as Vivian (2010, pp. 40-41) but 
sampled slightly earlier in 2010. Nonetheless, the methods used during 
2009-2010 sampling were internally consistent, and these results 
demonstrate that the caddisfly occurs in varying densities across its 
range (Vivian 2010, pp. 40-41; Harner 2012, pers. comm.). Although some 
densities reported by Vivian (2010) are low compared to what has been 
reported for other caddisfly species (Mayer and Likens 1987, p. 266; 
Roeding and Smock 1989, p. 152; Bunn and Hughes 1997, pp. 343-344; 
Stewart and Downing 2008, p. 145), observations on the numbers and 
density variations of Platte River caddisfly larvae and adults are 
consistent with those reported for other Ironoquia species (Flint 1958, 
p. 60; Swegman et al. 1981, p. 131; MacLean and MacLean 1984, p. 56; 
Garono and MacLean 1988, p. 147; Gray and Johnson 1988, p. 180; 
[Cacute]uk and Vu[ccaron]kovi[cacute] 2010, pp. 233-234). Therefore, 
the Platte River caddisfly and Ironoquia spp., in general, are more 
abundant in some areas than in others.
    Although population densities have been reported for over half of 
all known Platte River caddisfly populations, there is a lack of 
general information on population trends for this species, with the 
exception of a few sites, including the type locality, Wild Rose 
Slough, one site near Shelton, Nebraska, and one site near Chapman, 
Nebraska, where restoration work conducted by the Service in 2007 
resulted in a population decline at that site. Sites with lower 
population densities may always remain naturally low. Therefore, with 
the information available and the increase in the number of known 
populations, it is difficult to discern if the number of Platte River 
caddisfly individuals and populations is remaining steady, increasing, 
or decreasing.

Summary of Information Pertaining to the Five Factors

    Section 4 of the Act (16 U.S.C. section 1533) and implementing 
regulations (50 CFR part 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 an endangered or 
threatened species 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 Platte River 
caddisfly in relation to the five factors provided in section 4(a)(1) 
of the Act is discussed below. In considering what factors might 
constitute threats to a species, we must look beyond the exposure of 
the species to a particular factor to evaluate whether the species may 
respond to that factor in a way that causes actual impacts to the 
species. If there is exposure to a factor and the species responds 
negatively, the factor may be a threat and, during the status review, 
we attempt to determine how significant a threat it is. The threat is 
significant if it drives, or contributes to, the risk of extinction of 
the species such that the species warrants listing as endangered or 
threatened as those terms are defined in the Act. However, the 
identification of factors that could impact a species negatively may 
not be sufficient to compel a finding that the species warrants 
listing. The information must include evidence sufficient to suggest 
that these factors are operative threats that act on the species to the 
point that the species may meet the definition of an endangered or 
threatened species under the Act.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

Landscape-Level Changes in Hydrology
    Reductions in groundwater levels or river flows as a result of 
water development can adversely impact aquatic habitats and their 
associated macroinvertebrate communities. Existing and future water 
development along the Platte, Loup, and Elkhorn Rivers could adversely 
impact the Platte River caddisfly and its habitat. Adverse impacts 
could occur through the loss of water during critical life stages or 
changes in hydrology that result in intermittent wetlands becoming too 
ephemeral to support the Platte River caddisfly. We examine this topic 
in detail below.
    Hydroperiod can be an important factor in determining the 
composition of macroinvertebrate communities in wetlands. For instance, 
Whiles and Goldowitz (2005, p. 466) found that slough hydroperiod 
influenced macroinvertebrate taxa diversity and abundance, with more 
taxa present in intermittent sloughs than in sloughs with more 
ephemeral or permanent hydroperiods. Sloughs with intermittent 
hydroperiods typically have fewer predators than permanent wetlands and 
can offer safe refugia for various taxa if they can withstand habitat 
drying (Williams 1996, p. 634; Wissinger et al. 1999, p. 2103; Tarr and 
Babbitt 2007, p. 3). Sites with more permanent hydroperiods likely 
offer a more suitable environment for potential predators of the 
caddisfly, such as fish and amphibians, thereby reducing larval 
densities (Whiles and Goldowitz 2001,

[[Page 52656]]

p. 1836; Whiles and Goldowitz 2005, pp. 468, 470). Certain permanent 
sloughs with the Platte River caddisfly also appear to be more food-
limited than others as these areas have less standing vegetation 
(Vivian 2011, p. 18). The amount of available food can limit the 
abundance of shredder species (Roeding and Smock 1989, p. 149), such as 
the Platte River caddisfly (Vivian 2011, p. 18).
    The type locality from which the Platte River caddisfly was 
described had an intermittent hydroperiod (Whiles et al. 1999, p. 536). 
The Platte River caddisfly was not found at four other sloughs near the 
type locality during the time of the life history study; these sloughs 
had hydroperiods that differed from that of the type locality--they 
were thought to be either too ephemeral or permanent for the caddisfly 
(Whiles et al. 1999, p. 542; Whiles and Goldowitz 2001, p. 1832; Whiles 
and Goldowitz 2005, p. 466). Also, the Wild Rose Slough site contains 
ephemeral, intermittent, and permanent reaches, and the Platte River 
caddisfly has only been observed in the intermittent (Vivian 2010, 
pers. obs.) and permanent reaches of the slough (Geluso et al. 2011, p. 
1022). In other parts of its range, the Platte River caddisfly has been 
found in sloughs with more permanent hydroperiods, albeit in lower 
numbers than in sloughs with intermittent hydroperiods (Vivian 2010, p. 
54; Geluso et al. 2011, p. 1022).
    The caddisfly occurs in higher densities in intermittent sloughs 
than in sloughs with permanent hydroperiods. For instance, the type 
locality and Wild Rose Slough have intermittent hydroperiods (Vivian 
2010, pers. obs.) and have supported or currently support the largest 
known larval densities of the Platte River caddisfly (Whiles et al. 
1999, p. 536; Vivian 2010, pers. obs.; Geluso et al. 2011, p. 1022). 
Relatively low densities of the caddisfly have been found at other 
sites that have longer hydroperiods and experience less water level 
fluctuation (Vivian 2010, p. 54). Thus, it is thought that sloughs with 
intermittent hydroperiods are ideal for the Platte River caddisfly. 
Although intermittent wetlands represent ideal Platte River caddisfly 
habitat, permanent wetlands may become important during and following a 
drought as sites that support source populations for recolonization 
following extended dry periods. However, ephemeral wetlands do not 
remain wet long enough to support the species' lifecycle.
    Overall, landscape-level changes in hydrology that result from 
reservoir construction, river channel diversions, and groundwater 
withdrawal for irrigation could adversely impact the Platte River 
caddisfly and its habitat through the loss of water during critical 
life stages or degradation of its habitat. Since European settlement in 
the 1850s, the Platte, Loup, and Elkhorn Rivers have all experienced 
some degree of water development for various purposes; the Platte River 
has experienced the largest amount of modification of these systems. 
Starting in the mid-1800s, the tributaries of the Platte River were 
gradually developed to deliver water for irrigation via main and 
lateral canals, and eventually larger water storage projects along the 
main channels of the river were constructed (Eschner et al. 1981, pp. 
3, 5). Water development projects were implemented to make the region 
more suitable for agriculture, and more than 7,000 canals were 
constructed along the river between 1851 and 1930 (Simons and 
Associates 2000, pp. 5-9). Over-appropriation of water in the Platte 
Basin became an issue as early as 1876, and dams were constructed to 
create more reliable supplies of water (Eschner et al. 1981, p. 10; 
Simons and Associates 2000, pp. 7-8).
    Several hundred storage reservoirs and six principal dams are 
present in the Platte River Basin, and together they impound more than 
7.6 million acre-feet of water for irrigation (Simons and Associates 
2000, p. 8). Each reservoir project contains several miles of 
associated canals (Simons and Associates 2000, p. 13). Because of dams 
and diversions along the Platte Basin, over 70 percent of the Platte 
River flow is estimated to be diverted before it reaches Lexington, 
Nebraska (Currier et al. 1985, p. 120; Sidle et al. 1989, p. 91), which 
is about 48 km (30 mi) upstream of where most Platte River caddisfly 
populations along the Platte River are found. As a result of this 
development, the river has been described as one of the most heavily 
managed river systems in the United States (Simons and Associates 2000, 
p. 14; LaGrange 2004, 274 15).
    The Loup River has also been impacted by water development 
projects. The Loup Basin includes the North, Middle, and South Loup 
Rivers, and within the basin there are four mainstem diversion dams 
(U.S. Bureau of Reclamation (USBR) 2011, entire). The largest diversion 
dam, the Loup Diversion Dam, diverts around 69 percent of the Loup 
River flow away from the main channel for a distance of 35 miles in 
Nance and Platte Counties in Nebraska (Loup Power District and HDR 
Engineering 2008, p. 4-39). Each diversion dam has several miles of 
associated lateral canals to divert water to irrigated farmland (USBR 
2011, entire). Also, three impoundments are present along tributaries 
of the Loup River Basin (Loup Power District and HDR Engineering 2008, 
pp. 3-5), but the system lacks mainstem dams. The Elkhorn River is 
generally free of impoundments and diversions (LaGrange 2004, p. 21; 
Peterson et al. 2008, p. 5).
Habitat Loss Resulting From Changes in Hydrology
    Dams and diversion projects are known to result in changes in 
hydrological, geophysical, and ecological characteristics of river 
systems (Simons and Associates 2000, p. 15; Schramm et al. 2008, pp. 
237-238). Dams and diversions dampen the natural flow regime and change 
the hydrology of river systems, contribute to the downcutting and 
degradation of the river bed, reduce the amount of sediment flowing 
downstream, and reduce the amount of water reaching floodplain wetlands 
(Kingsford 2000, p. 109; Bowen et al. 2003, p. 809). These changes 
affect the ability of managed river systems to remain in a state of 
dynamic equilibrium, which contributes to the creation and maintenance 
of a diversity of habitats along a river's floodplain (Bowen et al. 
2003, p. 809). Water development projects may ultimately cause a river 
to become disconnected from its floodplain (Bowen et al. 2003, p. 809) 
and reduce the ability of rivers to continually inundate and create new 
backwater habitats via peak flows (Schramm et al. 2008, pp. 237-238).

Channel Narrowing

    As a result of reduced flow through the Platte River system, the 
main channel of the Platte River narrowed by about 65 to 80 percent 
between the mid-19th century and 1969 (Williams 1978, p. 8; Eschner et 
al. 1981, p. 45) and further narrowed by up to 25 percent between 1970 
and 1999 (Murphy et al. 2004, p. 102). Channel narrowing has resulted 
in a reduction in wetland habitat along the Platte River through a 
drying of adjacent sloughs. Between 1938 and 1982, an estimated 45.2 
percent of wet meadow habitat along the central Platte River was lost 
(Sidle et al. 1989, pp. 98-99), and this corresponded to a 53.4 percent 
reduction in active channel width during the same time period (Peake et 
al. 1985, entire; Sidle et al. 1989, pp. 98-99). The drying of linear 
slough depressions along the river also facilitated the development of 
row crops along what used to be wet bottomlands (Currier et al. 1985, 
p. 113).

[[Page 52657]]

Many wetlands were initially converted to cropland through wetland 
draining via ditches and land leveling (Currier et al. 1985, p. 113). 
Wetland losses and channel shrinkage data for the Loup River are 
currently unavailable; however, wetland losses have likely occurred 
concurrent with the narrowing of the river channel downstream of 
diversion projects.
    Historically, channel narrowing on the Platte and Loup River 
systems resulting from water development likely resulted in direct 
losses of suitable Platte River caddisfly habitat prior to the species' 
discovery in the late-1990s. During recent survey efforts, the Platte 
River caddisfly was not found between Hershey and Elm Creek, Nebraska, 
despite 24 surveys being conducted in this reach (Vivian 2010, p. 50). 
We do not know if the caddisfly ever occurred in this stretch of river, 
but it is present upstream and downstream of Hershey and Elm Creek, 
Nebraska, respectively (Vivian 2010, p. 50), and this stretch is likely 
one of the most dewatered and incised (disconnect of a river from its 
floodplain as a result of a decline in river bed elevation) portions of 
the Platte River (Murphy et al. 2004, p. 56). Since the species was 
first described in 2000, no known population losses have occurred as a 
result of channel narrowing and subsequent wetland drying.
    Aside from the draining of adjacent wetlands, channel narrowing has 
resulted in an increase in woody vegetation cover along the Platte 
River (Johnson 1994, entire). Downstream of Kearney, Nebraska, channel 
narrowing continues to reduce the amount of active channel area, and 
the amount of forest cover continues to increase (Murphy et al. 2004, 
p. 95), despite no new impoundments having been constructed in the 
Platte basin since 1956 (Johnson 1994, pp. 77-78). The establishment 
and proliferation of woody vegetation along the river acts to stabilize 
the river and can further contribute to channel narrowing through the 
trapping of sediments (Friedman et al. 1996, p. 341). Meanwhile, an 
increase in forest cover is not thought to have an adverse impact on 
the Platte River caddisfly, because most known caddisfly populations 
are found in forested wetlands, and some forested sloughs support 
relatively high larval densities of the Platte River caddisfly (Vivian 
2010, p. 64). It is unlikely that any future increases in forest cover 
will adversely affect the Platte River caddisfly.

Channel Degradation

    Aside from channel narrowing, impoundments and diversions can 
contribute to the downstream degradation of river systems, and these 
projects can have lasting impacts. Impacts to the Platte River 
resulting from past water development projects, which may affect the 
caddisfly, are ongoing. For instance, reduced sediment loads resulting 
from impoundments that block the passage of sediments and water 
discharges below diversion returns and dams are known to impact river 
systems and result in channel bed degradation. The North Platte River 
historically provided the majority of the sandy sediment to the Platte 
River system, but the amount of sediment inputs to the river greatly 
declined with the closing of the mainstem dams on the North Platte 
River (Murphy et al. 2004, p. 101). Near Overton, Nebraska, the 
Johnson-2 (J-2) diversion return releases sediment-free water into the 
Platte River and creates localized scour and an additional sediment 
imbalance.
    As a result of impoundments and diversion returns, less sediment 
flows into the Platte River than flows out, and this contributes to the 
erosion and a lowering of elevation of the river bed (Murphy et al. 
2004, p. 101). Erosion may also result from a coarsening of sediments 
in the river, which is a result of coarser sediment being supplied from 
the South Platte River as opposed to the fine sands that used to come 
from the North Platte River (Murphy et al. 2004, p. 115). Erosion 
results from a change in sediment size, because smaller sediment is 
transported downstream more quickly than coarser sediments (Murphy et 
al. 2004, p. 119). This downcutting (or incision) further narrows the 
active channel and acts to drain adjacent floodplain wetlands (Murphy 
et al. 2004, p. 129). Channel incision resulting from the sediment 
imbalance along the Platte River is thought to be largely complete 
upstream of Kearney, Nebraska, but has only slightly affected the river 
between Kearney and Grand Island, Nebraska, indicating that the trend 
of degradation is moving downstream (Murphy et al. 2004, pp. 113, 129). 
Channel incision and degradation resulting from the sediment imbalance 
in the Platte River and a coarsening of sediments is anticipated to 
take decades to be fully complete (Murphy et al. 2004, pp. 128-130).
    The effects of channel degradation and its impacts on the Platte 
River caddisfly and its habitat can be observed downstream of the J-2 
return. Diversion returns, like the J-2 return, that put clear water 
directly into the main channel of the Platte River, can contribute to 
the downcutting of the river bed and subsequent draining of adjacent 
floodplain wetlands. For instance, in 2010, surveys for the Platte 
River caddisfly were conducted downstream of the J-2 return near 
Overton, Nebraska, at Dogwood Wildlife Management Area (WMA). Within 
the WMA, several linear depressions were observed, and these areas were 
dry but showed signs of past beaver (Castor canadensis) activity, 
indicating that the area had once supported slough habitat (Vivian 
2010, p. 51). Given that the depressions were dry, habitat for the 
caddisfly was absent (and so was the species) and, therefore, it seems 
that the downcutting of the Platte River near Overton, Nebraska, has 
contributed to the loss of potentially suitable caddisfly habitat at 
Dogwood WMA.
    The effects of the J-2 return can be observed up to 29 km (18 mi) 
downstream of the return, although these effects are most pronounced 
closest to the return (Murphy et al. 2004, p. 142). Between 1989 and 
2002, the Platte River bed depth eroded 1.8 meters (6 feet) immediately 
downstream of the J-2 return, and eroded 0.76-meter (2.5 feet) 29 km 
(18 mi) downstream from the return during the same time period (Murphy 
et al. 2004, p. 106). At Grand Island, Nebraska, the river bed eroded 
0.27-meter (0.89-foot) between 1933 and 1995 (Murphy et al. 2004, p. 
113). It is anticipated that the process of incision as a result of the 
J-2 return will continue downstream all the way to Grand Island, but it 
is expected to progress slowly (Murphy et al. 2004, pp. 113-114). For 
instance, the river could incise by 0.60-meter (2 feet) from 1940 bed 
elevation levels within 100 years, 48 km (30 mi) downstream of the 
return. However, these same impacts are expected to take 400 years to 
affect the area 100 km (60 mi) downstream of the return (Murphy et al. 
2004, p. 114), an area where seven of the 35 known Platte River 
caddisfly populations occur. This incision could further narrow the 
central Platte River and contribute to the draining of adjacent 
wetlands and sloughs occupied by the Platte River caddisfly.
    It is likely that channel incision has contributed to a loss in 
available Platte River caddisfly slough habitat in the past and could 
adversely affect the remaining sloughs on the central Platte River 
(Lexington, Nebraska to Chapman, Nebraska, where several populations of 
the Platte River caddisfly occur) in the future. The impacts of channel 
degradation on Platte River caddisfly habitat are best demonstrated by 
the effects observed at Dogwood WMA and

[[Page 52658]]

at the Crane Trust on Shoemaker and Mormon Islands. Harner and Whited 
(2011, pp. 17-18; Harner 2012, pers. comm.) demonstrated that although 
there was two times more river discharge in the Platte River in 1999 
than in 1951, less slough habitat was available at the Crane Trust in 
1999 than was present in 1951. Between 1951 and 1999, the amount of 
available slough habitat declined by 0.3-hectare (0.8-acre) at Wild 
Rose Slough (which is deeper and more entrenched, resulting in less 
surface area lost) on Shoemaker Island and 3.6 hectares (8.8 acres), or 
about 28 percent, at the type locality on Mormon Island (Harner and 
Whited 2011, pp. 17-18). Declines in the amount of slough habitat were 
attributed to channel incision of the Platte River, or a drop in the 
groundwater table, or both, as land leveling has not occurred along the 
stretch of the river owned by the Crane Trust. These results 
demonstrate that even though river discharge in 1999 was greater than 
in 1951, more water in the Platte River does not necessarily mean that 
the floodplain will be inundated enough by elevated groundwater to 
support sloughs where the Platte River caddisfly occurs (Harner and 
Whited 2011, p. 23).
    Currently, the Crane Trust area supports the highest known 
densities of the Platte River caddisfly (Whiles et al. 1999, p. 537; 
Vivian 2010, p. 47; Geluso et al. 2011, p. 1022) and is one of the 
largest remaining stretches of intact prairie in the Central Platte 
Valley. However, although the Crane Trust protects the parcel where the 
caddisfly occurs, this area is not buffered from the effects of 
upstream water development and nearby groundwater pumping (Harner and 
Whited 2011, pp. 23-24; Harner 2011, pers. comm.). The documented 
decline in the amount of available slough habitat between 1951 and 1999 
(Harner and Whited 2011, entire) illustrates that effects of past and 
current degradation to the river channel are ongoing even though there 
have been no major water projects implemented on the Platte River since 
1956 (Johnson 1994, p. 78). If left unchecked (Murphy et al. 2004, p. 
114), future channel degradation could eventually result in as much as 
a total loss of Platte River caddisfly habitat at the Crane Trust and 
other nearby sloughs. For instance, Harner and Whited (2011, p. 14) 
demonstrated that groundwater declines greater than 0.5-meter (1.5-2.0 
feet) from 1999 levels could result in slough drying at the type 
locality in years with similar precipitation and river discharge 
(Harner and Whited 2011, p. 20).
    Although Harner and Whited (2011) demonstrated an ongoing trend in 
channel degradation within the central Platte River near the Crane 
Trust at Alda, Nebraska, the Platte River caddisfly is still present at 
the type locality and Wild Rose Slough more than 10 years following 
1999 (year of reference used in the study). There are also extant 
Platte River caddisfly populations upstream of the Crane Trust, where 
the effects of channel degradation are more pronounced, such as near 
Elm Creek, Nebraska, where the channel bed incised by 0.76-meter (2.5 
feet) between 1989 and 2002 (Murphy et al. 2004, p. 106). Meanwhile, 
the type locality and Wild Rose Slough occur more off channel than the 
forested sloughs adjacent to the river channel and may be less buffered 
from the effects of channel incision, because hydroperiod is known to 
decrease with increasing distance from the river channel (Whiles et al. 
1999, p. 533). Therefore, habitat loss at the Crane Trust likely does 
not represent the norm throughout the range of the Platte River 
caddisfly.
    If left unchecked, future channel degradation could result in 
future losses in slough habitat and subsequent extirpation of the 
Platte River caddisfly from the central Platte River. However, various 
programs and entities are acting to maintain current habitat conditions 
on the central Platte River. The central Platte River is actively 
managed by several organizations to benefit endangered (E) and 
threatened (T) species (whooping crane (Grus americana) (E), interior 
least tern (Sterna antillarum athalassos) (E), piping plover 
(Charadrius melodus) (T), and pallid sturgeon (Scaphirhynchus albus) 
(E)) that depend on an open and braided river system. One such 
organization is the Headwaters Corporation, which is the 
nongovernmental organization responsible for overseeing the Platte 
River Recovery Implementation Program (PRRIP) (discussed more below and 
under Factor D).
    PRRIP was established in 2006, by an agreement between the Bureau 
of Reclamation, the Service, and the States of Colorado, Wyoming, and 
Nebraska to manage Platte River flows and habitat to meet the needs of 
endangered and threatened species that use the Platte River. For 
instance, PRRIP plans to clear and lower vegetated islands in the river 
to create a more open channel to benefit endangered species, and this 
action would increase the amount of sediment in the river (Murphy et 
al. 2004, p. 143; U.S. Department of the Interior (DOI) 2006, p. 5-60). 
PRRIP also seeks to offset the sediment imbalance in the river by 
adding sand to the central Platte River (DOI 2006, p. 5-55) and release 
pulse flows to maintain present channel conditions (DOI 2006, p. 3-11). 
Outside PRRIP, some work of removing riparian vegetation has already 
been executed by organizations such as the Nebraska Public Power 
District (Kinzel et al. 2006, entire). Other entities, such as the 
Partners for Fish and Wildlife Program (PFW), are actively restoring 
sloughs along the central Platte River to benefit wildlife, and these 
areas could eventually provide suitable habitat for the Platte River 
caddisfly. Ongoing efforts to maintain and improve current conditions 
along the central Platte River should help stem the ongoing degradation 
of the river and reduce the amount of potential losses of slough 
habitat throughout the Platte River portion of the species' range.
    As mentioned previously, water development on the Loup and Elkhorn 
Rivers has not been as extensive as it has along the Platte River. 
While there are diversions in place along the Loup River, these 
diversions have not resulted in extensive channel incision and 
degradation as has been observed along the Platte River. This can be 
demonstrated by the lack of vegetation encroachment onto the active 
river bed. Channel narrowing downstream of diversion projects on the 
Loup River Basin has likely resulted in a loss of slough habitat in the 
past. However, the Platte River caddisfly is present immediately 
upstream of Kent Diversion Dam, and the species is present immediately 
downstream of the Loup Diversion Dam. The populations in the vicinity 
of these projects appear secure, because there appears to be ample 
slough habitat to support the caddisfly at these sites (Vivian 2010, 
pers. obs.). Potentially suitable habitat that has not been surveyed is 
also present downstream of all four main diversion projects in the Loup 
River Basin (Vivian 2012, pers. obs.). Meanwhile, no large-scale 
projects on the Loup or Elkhorn Rivers are planned. Because of ongoing 
efforts to maintain present channel conditions in the central Platte 
River, which is the most degraded portion of the range of the Platte 
River caddisfly, and because of a general lack of channel degradation 
on the Loup and Elkhorn Rivers, we conclude that channel degradation 
does not pose a threat to the Platte River caddisfly.

Altered Hydrograph

    An altered hydrograph (graph of stream flow through time) can 
result

[[Page 52659]]

from dams and diversion projects. For instance, dams impound water and 
reduce the amount of water flowing through a river system. Diversion 
projects can result in a changed hydrograph by altering the timing of 
flows through a river system and can reduce the amount of water flowing 
downstream. Historically, the Platte River received a late-spring rise 
as a result of runoff from Rocky Mountain snowmelt, and water levels 
then receded through the summer months, with the river nearly drying 
completely in some years (Eschner et al. 1981, pp. 19-20; Simons and 
Associates 2000, p. 8). Because of water development projects, 
primarily dams, the historical hydrologic regime of the Platte River 
has been altered. For instance, at North Platte, Nebraska, peak flows 
declined from 20,000 cubic feet per second (cfs) in the late 1800s to 
less than 5,000 cfs after 1940 (Simons and Associates 2000, p. 16). 
Dams are also known to augment base flows in a river system, meaning 
that some floodplain wetlands never go dry (Kingsford 2000, p. 111). 
Following water development on the Platte River, periods of no or 
little flow have decreased (Simons and Associates 2000, p. 44). A 
reduction in natural periods of low flow could impact the intermittency 
of sloughs where the Platte River caddisfly occurs by increasing the 
permanency of water in certain areas. Despite the potential for sloughs 
along the Platte and Loup Rivers to be more permanent, the Platte River 
caddisfly has presumably existed with the presence of dams on the 
landscape for over 100 years. The species also occurs in permanent 
sloughs, and these areas could become important source populations for 
other intermittent wetlands following extended dry periods or drought. 
Wetlands that were historically intermittent may have become ephemeral 
wetlands unsuitable for the caddisfly concurrent with water 
development. However, we have no information to indicate that this has 
occurred since the species was described in 2000.
    At this time, there is no available information to indicate that an 
altered hydrograph is adversely affecting any populations of the Platte 
River caddisfly or has resulted in population losses throughout its 
range. Therefore, we do not consider a changed hydrograph to pose a 
threat to the Platte River caddisfly.

Invasive Species

    Along the Platte River, changes in hydrology have contributed 
significantly to the encroachment of woody and exotic vegetation onto 
what used to be the active river bed (Currier et al. 1985, p. 119; 
Johnson 1994, p. 47). In 2002, several areas of the Platte River went 
completely dry for 2 months because of drought, and in 2003, low to 
zero flows were recorded for extended periods of time within the Big 
Bend reach of the Platte (80-mile stretch of the Platte River between 
Overton and Chapman, Nebraska) (Service 2006, p. 113). During this 
time, dense invasive vegetation grew within the Platte River channel as 
a result of lower flows. Phragmites australis (common reed or 
Phragmites) and Phalaris arundinacea (reed canarygrass), two non-
native, invasive species, have proliferated on previously barren 
sandbars and in wetlands along the Platte River in the last decade. 
Historically, encroaching vegetation would have been washed away by ice 
scour, or high spring flows (now dampened by water development), or 
both (Service 2006 p. 163), but active removal is now required to keep 
invasive species in check. Invasive species have not proliferated on 
the Loup and Elkhorn Rivers as much as on the Platte. Only P. 
arundinacea has been observed in sloughs along the Loup River and in 
lower abundances than in sloughs along the Platte River.
    In the United States, there are introduced and native varieties of 
Phragmites australis, and the introduced and hybridized forms have 
become highly invasive in several States, including Nebraska (NRCS 
2002, entire; Blossey 2003, entire). P. australis can be up to 15 feet 
tall and quickly crowds out native wetland species once established 
(Michigan Department of Environmental Quality 2011, entire). There are 
also native and introduced ecotypes of Phalaris arundinacea, and the 
species can be aggressive and invade wetlands. P. arundinacea has been 
observed to form dense, monotypic stands and impenetrable mats of stems 
and leaves and crowd out native plant species (Wisconsin Department of 
Natural Resources 2007, entire). P. arundinacea was introduced from 
Europe for agricultural use (Maurer et al. 2003, p. 16) and may be the 
most pervasive emergent plant in wetlands in the Midwest (Spyreas et 
al. 2010, p. 1254). Both P. australis and P. arundinacea have likely 
spread along the Platte River as a result of deliberate introductions 
and changes in hydrology (Andersen et al. 2004, p. 787; Strayer et al. 
2006, p. 649).
    Both Phragmites australis and Phalaris arundinacea have been 
observed in sloughs where the Platte River caddisfly occurs; however, 
P. arundinacea is more abundant and more often encountered in these 
wetlands (Vivian 2010, pers. obs.). These invasive plant species have 
been observed at 24 out of 35 sites with the caddisfly (Vivian 2011, 
pers. obs.) and appear to have degraded habitat at five sites with the 
caddisfly along the Platte River. At three sites, P. arundinacea 
appears to have grown thick enough to completely dry out slough margins 
and to have reduced the amount of available Platte River caddisfly 
habitat at these sites (Vivian 2009, pers. obs.). P. australis is or 
was the dominant vegetation present at two sloughs where the caddisfly 
occurs when these areas were surveyed (Vivian 2009, pers. obs.); this 
plant has potentially reduced the habitat quality at these sites, as 
these sites support the lowest known densities of the Platte River 
caddisfly (Vivian 2010, p. 64.). Nonetheless, no extirpations have been 
observed as a result of displacement by invasive species, and work is 
underway along the central Platte River to control and reduce the 
spread of P. australis (The Nature Conservancy 2011, entire). In other 
sloughs that support exotic vegetation, there is no evidence to suggest 
that P. australis or P. arundinacea are encroaching to the point where 
habitat quality is being reduced or will be reduced in the near future. 
Because invasive species appear to be impacting the Platte River 
caddisfly at only a small number of sites throughout its range, we do 
not consider invasive plant species to pose a threat to the Platte 
River caddisfly.
Groundwater Development
    Following dam construction in the Platte Basin, irrigation demands 
were met through the pumping of groundwater (Eschner et al. 1981, p. 
10), particularly along the central Platte River (Currier et al. 1985, 
p. 87). The central Platte River remains the most heavily irrigated 
region in Nebraska, with an average of 2 to 16 registered groundwater 
wells per mile (University of Nebraska at Lincoln, School of Natural 
Resources (UNL-SNR) 2011a, entire). As of 2008, there were 1.3 million 
acres of irrigated cropland within the Loup Basin (Loup Power District 
and HDR Engineering 2008, p. 3-1). Throughout most of the Loup and 
Elkhorn Basins, there are up to 4 registered irrigation wells per mile, 
but there can be up to 16 wells per square mile in the Loup Basin (UNL-
SNR 2011a, entire).
    Groundwater pumping can result in a lowering of the water table and 
contribute to subsequent wetland drying and loss (van der Kamp and 
Hayashi 1998, p. 51; LaGrange 2004, p. 13). It is possible that pumping 
groundwater for

[[Page 52660]]

irrigation contributed to some Platte River caddisfly habitat loss 
historically throughout the species' range, particularly in the central 
Platte River (Big Bend reach) where irrigation dominates the valley 
(Currier et al. 1985, p. 87). However, available data on monitored 
groundwater levels do not indicate that this has occurred or is 
occurring on a wide scale throughout the range of the Platte River 
caddisfly.
    Along the eastern portion of the central Platte River (east of 
Buffalo County line), groundwater levels in some isolated areas near 
the river declined 1.5 to 3.0 meters (5 to 10 feet) between pre-
development (1950 or later for some parts of Nebraska) (McGuire 2011, 
pp. 1, 4) and spring 2011 (UNL-SNR 2011b, entire). The remainder of the 
groundwater table near the Platte River experienced little to no change 
or an increase (UNL-SNR 2011b, entire). Throughout the entire central 
Platte region and near the river, the groundwater table declined 0.3 to 
1.5 meters (1 to 5 feet) between spring 2001 (species described in 
2000) and spring 2011 (UNL-SNR 2011c, entire) but increased 0.6 to 1.5 
meters (2 to 5 feet) between spring 2006 and spring 2011 (UNL-SNR 
2011d, entire). The groundwater level declines observed between 2001 
and 2011 may be attributed to drought conditions in Nebraska during the 
first half of the 2000s (see Climate Change, below).
    Aside from a few small, isolated areas where groundwater levels 
declined close to the Loup River, between 1950 and 2011, groundwater 
levels increased by at least 1.5 meters (5 feet) throughout most of the 
Loup and part of the Elkhorn Basins (UNL-SNR 2011b, entire). Elsewhere 
in the Elkhorn Basin, there was no change in observed groundwater 
levels between 1950 and 2011 (UNL-SNR 2011b, entire). It is unlikely 
that observed increases in the groundwater table along the Loup and 
Elkhorn Rivers have contributed to losses in the amount of slough 
habitat available to the caddisfly.
    Where groundwater levels have dropped within the range of the 
Platte River caddisfly, it is possible that a loss in slough habitat 
has occurred through the loss of inundated wetland acres. However, 
since the species was described, drops in the groundwater table due to 
pumping are not known to have resulted in extirpations of any caddisfly 
populations. Also, the amount of loss in slough habitat is likely 
limited, because the groundwater table dropped in only three isolated 
areas within the range of the caddisfly between 1950 and 2011 (UNL-SNR 
2011b, entire). Only one of these areas overlaps with extant Platte 
River caddisfly populations, and this area is along the central Platte 
River. The other two areas near where groundwater levels have declined 
since pre-development support slough habitat that has not yet been 
surveyed for the caddisfly.
    There is the potential for ongoing and future groundwater 
withdrawals to adversely impact the Platte River caddisfly and its 
habitat in the future, particularly given the recent increase in demand 
for grain. For instance, in the Lower Loup Natural Resources District 
(LLNRD), which encompasses the Loup River and its tributaries upstream 
of Columbus, Nebraska, to the west end of Loup and Custer Counties, 
10,000 additional acres were approved to be added to the amount of 
irrigated acres between 2010 and 2013 (Lower Loup Natural Resources 
District 2011, entire), and so the groundwater table in that region may 
see declines with the increase in irrigation. Within the Central Platte 
Natural Resources District (CPNRD), 2,500 new acres were opened for 
development in 2012 downstream of Chapman, Nebraska. Future declines in 
the amount of slough habitat on the Platte, Loup, and Elkhorn Rivers 
associated with the increased demand for groundwater usage may occur.
    Although the amount of slough habitat available to the caddisfly 
has the potential to decline in the future concomitant with the 
increase in grain production across at least some of the species' 
range, existing regulations are likely to limit the extent to which 
this can occur. Along most of the central Platte River, we have 
determined that groundwater sources are relatively secure, because, 
presently, there is a moratorium on new groundwater wells that pump 
more than 50 gallons per minute, and no new well permits can be issued 
unless the amount of consumptive water use is offset (retired elsewhere 
in the basin) (CPNRD 2011, pp. 3-4). Therefore, current conditions are 
not anticipated to worsen with respect to groundwater pumping in the 
central Platte Basin, which is considered to be the most degraded 
portion of the species' range. Also, because the sloughs along the 
Platte River are closely tied to surface water flows within 0.8 km (0.5 
mi) of the river (Hurr 1981, p. H7), efforts to increase shortages to 
target flows in the Platte River under the PRRIP should maintain 
current conditions in sloughs along the river. Elsewhere in the Loup 
and Elkhorn Basins, groundwater and surface water resources are being 
managed by Nebraska's natural resources districts, and by State law, 
these areas cannot exceed the fully appropriated designation.
    As part of Nebraska State law LB 962, passed by the State 
legislature in 2004, groundwater well permits and surface water permits 
are carefully managed so that river flows do not reach the over-
appropriated designation, because it has been recognized that surface 
flows are tied to groundwater levels near the river and vice versa. 
Nebraska State law requires that there be a balanced use of ground and 
surface waters in Nebraska to ensure the long-term sustainability of 
these supplies (Peterson et al. 2008, p. 2). Limited numbers of acres 
are being allowed for well drilling on an annual basis in the Loup and 
Elkhorn Basins. However, stays are placed on the construction of new 
wells once a river basin is deemed fully appropriated (Ostdiek 2009, p. 
2). A fully appropriated designation ((Neb. Rev. Stat. Sec.  46-713(3) 
(Reissue 2004, as amended)) means that based on current groundwater and 
surface water usage, average streamflows are insufficient to meet the 
long-term demands within a basin (Peterson et al. 2008, p. 5). 
Following any fully appropriated designation, the Nebraska Department 
of Natural Resources (NDNR) and applicable natural resource district 
must create an integrated management plan to achieve a sustainable 
balance between water demands and supplies (Peterson et al. 2008, p. 
5). If an area becomes over-appropriated, State law requires that the 
applicable natural resource district work with its stakeholders on 
returning the basin to a fully appropriated status (Ostdiek 2009, p. 
2).
    Since the Platte River caddisfly was described in 2000, no 
information has become available to indicate that any net loss in 
slough habitat has occurred as a result of groundwater pumping. At this 
time, the Service does not have data showing that the quantity of water 
has been lowered or that the current water withdrawals are impacting 
the Platte River caddisfly habitat or will impact the Platte River 
caddisfly in the near future. Declines in the groundwater table due to 
drought resulted in two localized caddisfly extirpations; however, the 
species is now found again at the type locality, and the groundwater 
table has since rebounded in that area. If habitat loss has occurred, 
we estimate that the amount has been negligible, because groundwater 
declines between 1950 and 2011 have occurred only within a small 
portion of the species' range. The Platte River caddisfly is extant in 
the area of the Platte River where the largest documented drops in the 
groundwater table have occurred. The species is also present in the 
area

[[Page 52661]]

of the Platte River where there is the highest density of registered 
irrigation wells (UNL-SNR 2011a, entire). Elsewhere, groundwater levels 
have increased, possibly because of seeps that parallel the river 
channel (Murphy et al. 2004, p. 47) and groundwater recharge from 
lateral canals (Peterson et al. 2008, p. 13), and, therefore, habitat 
losses cannot be attributed to a declining aquifer.
    Current moratoria in the Platte Basin, which includes a moratorium 
on new surface water diversions (NDNR 2008, entire), should prevent 
current conditions from worsening throughout the most degraded portion 
of the species' range along the central Platte River. Current State law 
and management by the State's various natural resources districts on 
the Loup and Elkhorn Rivers should maintain the groundwater table at 
sustainable levels in those areas. For instance, the Loup and Elkhorn 
River Basins are subject to limited surface water appropriations, 
because the NDNR has to ensure adequate flows exist in the Lower Platte 
Basin for endangered species, such as the pallid sturgeon (NDNR 2006, 
p. E-11). Overall, we have determined that groundwater withdrawal does 
not pose a threat to the species. However, additional stress from water 
demand is likely to be placed on Nebraska's river systems in the future 
as a result of climate change and projected increases in floods and 
droughts (discussed below).
Climate Change
    Global climate change is a concern, because it has the potential to 
reconfigure the spatial distribution of species and their habitats 
worldwide throughout the 21st century and beyond. Our analyses under 
the Act include consideration of ongoing and projected changes in 
climate. The terms ``climate'' and ``climate change'' are defined by 
the Intergovernmental Panel on Climate Change (IPCC). The term 
``climate'' refers to the mean and variability of different types of 
weather conditions over time, with 30 years being a typical period for 
such measurements, although shorter or longer periods also may be used 
(IPCC 2007a, p. 78). The term ``climate change'' thus refers to a 
change in the mean or variability of one or more measures of climate 
(e.g., temperature or precipitation) that persists for an extended 
period, typically decades or longer, whether the change is due to 
natural variability, human activity, or both (IPCC 2007a, p. 78).
    Scientific measurements spanning several decades demonstrate that 
changes in climate are occurring, and that the rate of change has been 
faster since the 1950s. Examples include warming of the global climate 
system, and substantial increases in precipitation in some regions of 
the world and decreases in other regions (IPCC 2007a, p. 30; Solomon et 
al. 2007, pp. 35-54, 82-85). Results of scientific analyses presented 
by the IPCC show that most of the observed increase in global average 
temperature since the mid-20th century cannot be explained by natural 
variability in climate, and is ``very likely'' (defined by the IPCC as 
90 percent or higher probability) due to the observed increase in 
greenhouse gas (GHG) concentrations in the atmosphere as a result of 
human activities, particularly carbon dioxide emissions from use of 
fossil fuels (IPCC 2007a, pp. 5-6 and figures SPM.3 and SPM.4; Solomon 
et al. 2007, pp. 21-35). Further confirmation of the role of GHGs comes 
from analyses by Huber and Knutti (2011, p. 4), who concluded it is 
extremely likely that approximately 75 percent of global warming since 
1950 has been caused by human activities.
    Scientists use a variety of climate models, which include 
consideration of natural processes and variability, as well as various 
scenarios of potential levels and timing of GHG emissions, to evaluate 
the causes of changes already observed and to project future changes in 
temperature and other climate conditions (e.g., Meehl et al. 2007, 
entire; Ganguly et al. 2009, pp. 11555, 15558; Prinn et al. 2011, pp. 
527, 529). All combinations of models and emissions scenarios yield 
very similar projections of increases in the most common measure of 
climate change, average global surface temperature (commonly known as 
global warming), until about 2030. Although projections of the 
magnitude and rate of warming differ after about 2030, the overall 
trajectory of all the projections is one of increased global warming 
through the end of this century, even for the projections based on 
scenarios that assume that GHG emissions will stabilize or decline. 
Thus, there is strong scientific support for projections that warming 
will continue through the 21st century, and that the magnitude and rate 
of change will be influenced substantially by the extent of GHG 
emissions (IPCC 2007a, pp. 44-45; Meehl et al. 2007, pp. 760-764, 797-
811; Ganguly et al. 2009, pp. 15555-15558; Prinn et al. 2011, pp. 527, 
529). (See IPCC 2007b, p. 8, for a summary of other global projections 
of climate-related changes, such as frequency of heat waves and changes 
in precipitation. Also see IPCC 2011 (entire) for a summary of 
observations and projections of extreme climate events.)
    Various changes in climate may have direct or indirect effects on 
species. These effects may be positive, neutral, or negative, and they 
may change over time, depending on the species and other relevant 
considerations, such as interactions of climate with other variables 
(e.g., habitat fragmentation) (IPCC 2007a, pp. 8-14, 18-19). 
Identifying likely effects often involves aspects of climate change 
vulnerability analysis. Vulnerability refers to the degree to which a 
species (or system) is susceptible to, and unable to cope with, adverse 
effects of climate change, including climate variability and extremes. 
Vulnerability is a function of the type, magnitude, and rate of climate 
change and variation to which a species is exposed, its sensitivity, 
and its adaptive capacity (IPCC 2007a, p. 89; see also Glick et al. 
2011, pp. 19-22). There is no single method for conducting such 
analyses that applies to all situations (Glick et al. 2011, p. 3). We 
use our expert judgment and appropriate analytical approaches to weigh 
relevant information, including uncertainty, in our consideration of 
various aspects of climate change.
    As is the case with all stressors that we assess, even if we 
conclude that a species is currently affected or is likely to be 
affected in a negative way by one or more climate-related impacts, it 
does not necessarily follow that the species meets the definition of an 
``endangered species'' or a ``threatened species'' under the Act. If a 
species is listed as endangered or threatened, knowledge regarding the 
vulnerability of the species to, and known or anticipated impacts from, 
climate-associated changes in environmental conditions can be used to 
help devise appropriate strategies for its recovery.
    The effects of climate change, such as an increase in the global 
average air surface temperature since 1970, are already being felt in 
North America and around the world (U.S. Global Change Research Program 
(USGCRP) 2009, pp. 9, 17). In the Rocky Mountains and Northern 
Hemisphere, there has been a decrease in overall snowpack cover over 
the past 100 years (IPCC 2007, p. 30), and the proportion of 
precipitation falling as snow is decreasing (USGCRP 2009, p. 43). More 
precipitation now falls in the form of extreme rain events (Rieman and 
Isaak 2010, p. 4). A decrease in annual snowpack is projected to lead 
to earlier spring snowmelt and runoff, reduced runoff and stream flow, 
decreased recharge of

[[Page 52662]]

aquifers, an increase in drought frequency and intensity, and shorter 
wetland hydroperiods (USGCRP 2009, p. 45; Johnson et al. 2010, p. 137; 
Rieman and Isaak 2010, pp. 4, 6, 8). Flooding risk is also projected to 
increase in association with warmer winters and earlier snowmelts 
(Saunders and Maxwell 2005, p. 1), and summer flows are expected to be 
lower (USGCRP 2009, p. 46). Decreases in the amount of snowfall and 
earlier snowmelt in the Rocky Mountains are most likely to affect the 
sloughs along the Platte River, because its flows are tied to Rocky 
Mountain snowmelt, while Loup and Elkhorn River flows are tied to the 
Ogallala Aquifer and local precipitation events.
    In the Great Plains, the average annual temperature has increased 
by 0.83 [deg]C (1.5[emsp14][deg]F) since the 1970s and is expected to 
increase 2.5 [deg]C (4.5[emsp14][deg]F) by 2050 (USGCRP 2009, p. 123) 
and between 4.2 [deg]C (8[emsp14][deg]F) and 5.0 [deg]C 
(9[emsp14][deg]F) by the 2080s across the range of the Platte River 
caddisfly (The Nature Conservancy 2007, entire). Should GHG continue at 
the current rate, average annual precipitation is expected to remain 
steady or decrease by 5 percent from today's levels across the range of 
the Platte River caddisfly by 2050 (The Nature Conservancy 2007, 
entire).
    Between the 1930s and 2011, average maximum temperatures have 
remained steady in the Lower Platte Basin (downstream of the North 
Platte/South Platte confluence), while there has been an increase in 
average maximum temperatures in the Upper Platte Basin (upstream of the 
confluence) for the same time period (Stamm 2012, pers. comm.). During 
the same time period, there has been a wetting trend in the Lower 
Platte Basin and a drying trend in the Upper Platte Basin (Stamm 2012, 
pers. comm.). Meanwhile, average minimum temperatures increased across 
the entire Platte Basin between the 1930s and the decade ending in 2011 
(Stamm 2012, pers. comm.). Available models for the Loup and Elkhorn 
River Basins demonstrate similar trends (https://www.climatewizard.org/, 
accessed June 25, 2012).
    Should worldwide GHG emissions remain the same as today's levels, 
starting in 2030, average temperatures are projected to increase 
dramatically across the entire Platte Basin and continue increasing 
through at least 2050, and precipitation is projected to remain steady 
or decrease slightly compared to the decade ending in 2011 (https://www.climatewizard.org/, accessed June 25, 2012). Average winter, 
spring, and fall temperatures are projected to increase by 1.0-2.5 
[deg]C (2.7-4.5[emsp14][deg]F), and summer temperatures will likely 
increase by 3.5-4.0 [deg]C (6.3-7.2 [deg]F) by 2050 when compared to 
the decade ending in 2011 (https://www.climatewizard.org/, accessed June 
25, 2012).
    Compared to the decade ending in 2011, by 2030, fall and winter 
precipitation is projected to remain steady or slightly decrease; 
spring precipitation could decline by 20-30 mm, and summer 
precipitation is projected to decrease by 50-60 mm for the Lower Platte 
Basin (https://www.climatewizard.org/, accessed June 25, 2012). 
Conditions are also expected to become hotter and drier in the Upper 
Platte overall (https://www.climatewizard.org/, accessed June 25, 2012). 
Because the sloughs along the Platte River receive snowmelt from the 
Rocky Mountains (Williams 1978, p. 1) and there is anticipated to be 
reduced snowpack, sloughs along the Platte River are likely to be more 
vulnerable to drying than sloughs along the Loup and Elkhorn Rivers 
during droughts.
    Although some models indicate parts of the range of the Platte 
River caddisfly could experience wetter winters and springs, projected 
increases in temperature could negate the effects of increased 
precipitation through increases in evaporation and transpiration 
(evaporation of water from plant leaves), particularly in the summer 
months (Sorenson et al. 1998, pp. 344-345, 355-356; Johnson et al. 
2010, p. 128). Increased evapotranspiration (combined effect of 
evaporation and transpiration) is expected to create drier conditions 
in the northern Great Plains, thereby increasing the frequency and 
severity of droughts (Sorenson et al. 1998, pp. 344-345; USGCRP 2009, 
p. 126). Overall, by 2030, the entire area will likely be hotter and 
drier compared to the decade ending in 2011 (Stamm 2012, pers. comm.). 
A hotter and drier climate represents the worst-case scenario for the 
Platte River caddisfly.
    The Great Plains system is known for its extensive inter-annual 
climate variability (Ojima et al. 1999, p. 1445), and episodic floods 
and droughts are characteristic of prairie streams (Dodds et al. 2004, 
pp. 205-206) where the Platte River caddisfly occurs. Species found in 
Great Plains aquatic systems and in intermittent waters, such as the 
Platte River caddisfly, are well-suited to survive these disturbance 
events and environmental extremes (Lytle 2002, pp. 370, 371). However, 
disturbances that occur outside the time when such events normally 
occur could cause mortality to species such as the Platte River 
caddisfly.
    Despite the projected increase in the frequency of droughts, 
projected increase in temperature, and projected decrease in 
hydroperiod length, the Platte River caddisfly presumably survived 
historical drought periods, particularly through the Dust Bowl (1930s). 
In 2004, following a dry spring, the type locality for the caddisfly 
was dry by early April, and adults were not found at that site in the 
fall of 2004, despite consistent emergence in the 7 years prior 
(Goldowitz 2004, p. 8). Platte River caddisfly adults were also not 
observed during surveys between 2007 and 2009 (Riens and Hoback 2008, 
p. 1; Vivian 2010, p. 48). In 2007 and 2009, the Platte River caddisfly 
was not observed at one site near Shelton, Nebraska, following the 
drought in central Nebraska in the early 2000s, and this site is still 
presumed to be extirpated (Riens and Hoback 2008, p. 1; Vivian 2010, p. 
48). Following wetter years in 2008 and 2009, the caddisfly was found 
at the type locality in 2010 (Geluso et al. 2011, p. 1023), indicating 
the species has the ability to recolonize suitable habitats following 
disturbance events. Alternatively, Platte River caddisfly population 
levels could have decreased to undetectable levels and then rebounded 
following wetter conditions, as it is easy to miss individual adults 
when conducting surveys in the autumn (Harner 2012, pers. comm.). It is 
unknown if the species has recolonized the site near Shelton, Nebraska.
    In normal years, the Platte River caddisfly is able to withstand 
normal summer dry periods through aestivation (Whiles et al. 1999, p. 
542). The burial behavior observed during the aestivation period in the 
Platte River caddisfly lifecycle likely protects the species against 
heat and desiccation (Geluso et al. 2011, p. 1024), and affords the 
species added protection during extended droughts. Furthermore, the 
related Ironoquia punctatissima (no common name) has been found to lay 
its eggs in a gelatinous matrix on a dry streambed with the larvae 
hatching once waters return (Clifford 1966, entire). It is unknown how 
long the eggs of this species or the Platte River caddisfly could 
survive without water, but this adaptation could provide the Platte 
River caddisfly protection in years with shorter hydroperiods, if it 
does exhibit this behavior. A shorter hydroperiod would likely be more 
detrimental in the spring if a slough dried too early as it could 
prompt the caddisfly to emigrate earlier from the aquatic environment, 
possibly reducing the size of the larva

[[Page 52663]]

and overall fitness of the individual (Harner 2011, pers. comm.).
    Recent modeling efforts demonstrated the potential effects of 
shorter periods of slough inundation on the Platte River caddisfly. 
Using long-term well data, Harner and Whited (2011, entire) created a 
model that demonstrated that during a dry period in the record (2000-
2003), the type locality slough held water for approximately 249 days, 
whereas during a wet period (1997-1999), the slough was wet for 
approximately 340 days (Harner and Whited 2011, p. 21). Most of this 
drying occurred in summer and fall, and adults were observed in 2003. 
Larvae were also present at the type locality in the spring of 2004; 
however, the slough dried more than 2 months earlier in 2004 than what 
had been observed in years prior, and adults were not observed in the 
autumn of 2004 (Goldowitz 2004, p. 9). Therefore, droughts that result 
in sloughs drying too early would likely be more detrimental to the 
caddisfly than prolonged drying into the autumn and could lead to 
localized extirpations.
    Drought has been implicated in at least the temporary loss of two 
Platte River caddisfly populations, one of them being the formerly 
robust type locality. Following the drought, the caddisfly is now again 
present at the type locality (Geluso et al. 2011, p. 1024) and possibly 
could have migrated downstream to a more permanent portion of the 
slough during the extended drought of the early 2000s (Vivian 2011, 
pers. obs.). Also, the type locality and population near Shelton, 
Nebraska, occur farther away from the main channel of the Platte River; 
these areas are less likely to withstand droughts than sloughs closer 
to the main channel, because hydroperiod decreases with increasing 
distance from the river (Whiles et al. 1999, p. 533). Throughout the 
rest of the range of the Platte River caddisfly, historical aerial 
imagery from 2003-2006, a period of drought, indicates that the 
remaining 33 sloughs where the caddisfly is known to occur likely held 
enough water to support the caddisfly (Vivian 2012, pers. obs.). Thus, 
it appears that the recent drought had localized effects on a few 
populations but was not an issue across the range of the species.
    Hotter and drier summers in the future are likely to result in 
increases in evapotranspiration, which may also lead to drier soil 
conditions (Sorenson et al. 1998, p. 344; Johnson et al. 2010, p. 134), 
and these conditions could impact aestivating caddisfly larvae in areas 
with an open canopy. However, most caddisfly populations occur in 
sloughs surrounded by a forest canopy, and this shade cover is likely 
to provide some protection against evaporative losses from soil and 
reduce the risk of desiccation (Vivian 2009-2010, pers. obs). The 
distribution and habitat of the Platte River caddisfly likely confer 
added protection for the species during times of drought and future 
climatic extremes. For instance, the species is known from the Platte, 
Loup, and Elkhorn Rivers, and the Loup and Elkhorn Rivers are tied more 
to groundwater inputs than snowmelt and precipitation. However, the 
sloughs along all three river systems are tied to groundwater levels to 
some degree, and groundwater-fed wetlands are thought to be less 
vulnerable to climate change than those more tied to inputs of 
precipitation (Winter 2000, p. 308). Because the caddisfly: (1) 
Presumably survived the Dust Bowl, a period of extreme dryness on the 
magnitude expected by climate change; (2) exhibits behaviors that 
enable it to survive extended dry periods; (3) spans a large geographic 
area that encompasses a range of annual average precipitation; and (4) 
is present in more than one habitat type across its range, including in 
areas that maintain water during droughts, we have determined that 
habitat impacts associated with climate change do not pose a threat to 
the caddisfly throughout its range.
Flooding
    The frequency and intensity of floods are projected to increase 
with the onset of climate change (Saunders and Maxwell 2005, p. 1). 
However, flooding is not likely to pose a significant threat to the 
Platte River caddisfly and could be of some benefit. Flooding events 
can scour aquatic organisms downstream in some systems (Feminella and 
Resh 1990, p. 2083), but the velocity at which Platte River caddisfly 
larvae are moved downstream is unknown. The caddisfly may not be 
subject to scouring flows, because it is found in lentic waters. 
Ironoquia punctatissima survives flood events with discharges of 100 
cm/s by seeking refuge in tangled grass roots (Williams and Williams 
1975, p. 829), and the Platte River caddisfly may exhibit similar 
behavior. It has also been recognized that the hyporheic zone 
(saturated subsurface region, area where groundwater and surface water 
mixing occurs (del Rosario and Resh 2000)) can be important in the 
recolonization of benthic macroinvertebrates following flood events 
(Williams and Hynes 1974, p. 234; Williams and Hynes 1976, p. 266; 
Boulton et al. 1998, p. 64), and the Platte River caddisfly has been 
found within the hyporheic zone in all five instar stages (Whiles et 
al. 1999, p. 535; Vivian 2010, pers. obs.). After high water in May to 
June 2010, which is during the terrestrial stage of the Platte River 
caddisfly lifecycle, several live individuals were found along the 
slough banks at two sites immediately after flood waters had receded 
(Vivian 2010, p. 52). The burial behavior observed in the Platte River 
caddisfly may protect a certain portion of terrestrial larvae from late 
spring floods (Geluso et al. 2011, p. 1024).
    Even if mortality of larvae were to occur due to scouring, flooding 
is likely important in the creation of backwater habitats and the 
subsequent increase in habitat availability to the Platte River 
caddisfly. Downstream larval drift is considered an important means of 
dispersal (Neves 1979, p. 58), but only in habitats that are connected 
by water (Petersen et al. 2004, p. 934). Caddisflies found in isolated 
habitats or pools are more likely to disperse via flight than by 
downstream larval drift, because these habitats are not connected 
(Williams 1996, p. 644; Petersen et al. 2004, p. 934). Some inhabitants 
of temporary wetlands may be strong fliers, such as some limnephilids 
(Svensson 1974, p. 174); however, observations conducted during the 
adult life stage suggest the Platte River caddisfly is a weak flier 
(Vivian 2010, p. 39). An increase in habitat availability due to 
flooding may increase the chances for the species to colonize new 
populations and link up areas of suitable habitat. Overall, flooding 
could increase the amount of suitable habitat for the Platte River 
caddisfly, and this would likely benefit the species. Because of 
various behaviors exhibited by the Platte River caddisfly that likely 
enable it to withstand flooding events, we do not consider flooding or 
the projected increase in flooding to pose a threat to the caddisfly.
Wetland Conversion and Modification
    As previously mentioned, historical water development in the Platte 
Basin contributed to a decline in the active floodplain, and opened up 
former wet bottomlands for crop development (Currier et al. 1985, p. 
113). Active efforts to drain wetlands to make an area suitable for row 
crops also historically contributed to wetland habitat loss, and there 
has been an estimated 73.5 percent loss of meadows within 3.5 miles of 
the Platte River as a result of channel narrowing and conversion for 
agriculture (Currier et al. 1985, p. 119). As of 1911, approximately 
1.5 million acres of grassland had been converted to row crops in the 
Platte Valley (Currier et al. 1985, p. 113). Agriculture, including the 
production of row crops,

[[Page 52664]]

is the predominant land use in Nebraska, and in recent years, a rise in 
ethanol production has led to an increase in grain prices, which in 
turn has led to an increase in the number of acres of corn planted in 
Nebraska (Nebraska Corn Board 2011, entire). Currently, the United 
States produces around 13 billion gallons of ethanol annually, but the 
Energy Independence and Security Act of 2007 (42 U.S.C. 17001 et seq.) 
mandates that this number increase to 36 billion gallons by 2022. 
Increases in the world's population also will likely lead to an 
increase in the demand for grain, and, in Nebraska, increasing grain 
production is contributing to a decline in grassland habitat.
    Concurrent with the increase in the planting of more acres of corn 
in Nebraska, ongoing wetland modification may result from the 
conversion of adjacent grasslands to row crops at a limited number of 
sites. In 2011, we consulted with the NRCS on approximately 70 
sodbuster applications received from Nebraska landowners. Sodbuster 
applications are submitted by individuals who desire to convert highly 
erodible grassland into crop production. The increase in sodbuster 
applications demonstrates that grassland habitats are continually 
vulnerable to the development of row crops.
    The Platte River caddisfly was discovered in a large, grassland 
complex. At the type locality and Wild Rose Slough, the caddisfly uses 
adjacent grassland habitat in which to aestivate and complete adult 
emergence. However, most Platte River caddisfly populations occur in 
forested sloughs adjacent to the main river channel, and these areas 
are thought to be buffered against conversion into row crops. Sloughs 
adjacent to the river also appear to be too deep to be suitable for 
filling and conversion for agriculture, and these sloughs are also 
protected from fill under the U.S. Army Corps of Engineers (Corps) 404 
program (discussed under Factor D). Therefore, there is not likely to 
be much overlap between the ongoing conversion of grassland into corn 
and Platte River caddisfly habitat. As a result, we do not consider 
wetland conversion to constitute a threat to the species.
Wetland Restoration
    Several nongovernmental organizations (NGOs) are actively restoring 
degraded wetlands in the central Platte region (Whiles and Goldowitz 
2005, p. 462); however, restored wetlands often do not equal natural 
wetlands in terms of floral and faunal diversity (Galatowitsch and van 
der Walk 1996, entire). Differences in wetland hydrology between 
natural and restored wetlands can affect the outcomes of restoration 
projects (Galatowitsch and van der Walk 1996, entire; Meyer and Whiles 
2008, entire). For instance, in central Nebraska, it has been shown 
that some aquatic taxa are missing entirely from restored sloughs as 
compared to natural sloughs (Meyer and Whiles, 2008, entire).
    Restored wetlands, although beneficial in providing habitat for 
some species, may not immediately provide suitable habitat for the 
Platte River caddisfly. Between 2009 and 2010, 12 restored sloughs were 
surveyed for the Platte River caddisfly, and only one slough had 
evidence of caddisfly presence (Vivian 2010, p. 46). One discarded case 
was found at this site, and it is unknown whether there is an extant 
population at this location, as no live individuals were found (Vivian 
2010, p. 17). When surveyed, restoration work had occurred 4 years 
prior to the survey (Schroeder 2011, pers. comm.), and it is unknown if 
the caddisfly was present before the restoration work had occurred. One 
other restored slough on Crane Trust property was previously found to 
support the Platte River caddisfly, but the site supported a low number 
of individuals. This site was near the type locality (Meyer and Whiles 
2008, p. 632; Meyer 2009, pers. comm.), which may represent a source 
population. These observations suggest that restored sloughs may not be 
immediately suitable to the caddisfly but could become more suitable 
over time as the restored sloughs become established.
    To date, only one restoration project is known to have resulted in 
adverse impacts to the Platte River caddisfly. At Bader Park near 
Chapman, Nebraska, a 2007 restoration project within a slough where the 
caddisfly was known to occur resulted in a decline in larval densities 
at that site (Harms 2009, pers. comm.). The caddisfly still occurs at 
that site, but at a density of less than one individual per m\2\ 
(Vivian 2010, p. 64), possibly because the slough now harbors various 
fish species that were not present before the restoration activities 
occurred. Since the Bader Park project, the Service has drafted 
guidelines to avoid adverse impacts to the caddisfly while conducting 
restoration work in sloughs where the species occurs. Overall, we think 
that restoration projects, if conducted with the Platte River caddisfly 
in mind, could provide benefits to the caddisfly in terms of an 
increase in the amount of available habitat, particularly in the long 
term. Thus, we have determined that wetland modification done as a part 
of restoration work does not pose a threat to the Platte River 
caddisfly.
Urbanization and Infrastructure
    It is likely that urbanization of the Platte River valley has 
impacted the habitat of the Platte River caddisfly in the past. For 
instance, 14 bridges span the North Platte and Platte Rivers between 
Chapman, Nebraska, and Lewellen, Nebraska, a distance of about 380 km 
(240 mi) (Currier et al. 1985, p. 56). Bridge construction can result 
in localized channel narrowing, because sediments get deposited 
upstream of the bridge site, and scour occurs downstream of the bridge 
site for at least a half-mile (Simons and Associates 2000, p. 67). 
Underneath bridges, channel incision may occur, leading to the 
degradation of adjacent wetlands as incision can lead to drawdowns of 
alluvial aquifers (Kondolf 1997, p. 542). Bridge choke points (areas 
immediately upstream and downstream of bridges where the river has 
narrowed) can also become open to sandpit development following channel 
narrowing.
    Beginning in the 1980s, the Federal Highway Administration (FHWA) 
implemented new requirements for bridges to prevent the encroachment of 
bridge embankments into river channels (Murphy et al. 2004, p. 52). 
Therefore, any present and future bridge projects are required to allow 
for sufficient room for a river to migrate and create and maintain 
backwater habitats. Ongoing effects to Platte River caddisfly habitat 
can be expected at bridge choke points, because no new habitat is being 
created in those areas. Recently, FHWA contacted the Service to 
coordinate ways to avoid and minimize impacts to slough habitat during 
a bridge project at Fullerton, Nebraska. No survey for the Platte River 
caddisfly has been conducted at that site, but coordination with FWHA 
demonstrates that potential adverse impacts on the caddisfly resulting 
from current and future bridge projects can be avoided. For bridge 
projects and other projects that are federally funded or authorized, 
the Service has the opportunity and does provide comments to addresses 
any concerns to listed species, candidate species, and species of 
concern, such as the Platte River caddisfly (see Factor D).
    Along Interstate 80, several sandpit lakes were created to extract 
gravel used for interstate construction in the 1960s (Currier et al. 
1985, p. 70); these past operations have been linked to wetland losses 
along the Platte River (Sidle et al. 1989, p. 99). Many of these areas 
now support housing developments adjacent

[[Page 52665]]

to the river, and these developments further confine the river to its 
banks through bank armoring, which reduces the ability of the river to 
create new channels and backwater areas (Schramm et al. 2008, p. 238), 
which are important habitat for the caddisfly. The construction of 
Interstate 80 has also contributed to a large amount of direct wetland 
losses north of the Platte River as the interstate runs within 0.25 
mile of the river for over 100 miles in Nebraska (Currier et al. 1985, 
p. 122).
    Bank stabilization and armoring projects constructed to protect 
property against erosion can also cause the localized scouring of a 
river channel and have the potential to lead to the drying of adjacent 
wetlands. Bank stabilization efforts, particularly under the Corps' 
nationwide permitting process, are ongoing throughout Nebraska and have 
the potential to impact occupied sloughs. However, only one of 35 sites 
with the caddisfly is currently adjacent to a bank stabilization 
project, and this site is just upstream of a bridge and does not appear 
to be degrading the quality of the slough (Vivian 2009, pers. obs.). We 
have no evidence to indicate that bank armoring along the Platte, Loup, 
and Elkhorn Rivers is occurring at a large enough scale to adversely 
impact the caddisfly and its habitat. We do not know of any current or 
future bank stabilization projects that are scheduled to occur near 
areas where the caddisfly has been found. Most Platte River caddisfly 
populations are considered to be protected from bank armoring projects, 
as 21 out of 35 sites with the caddisfly occur on protected lands.
    Overall, most impacts from urbanization and infrastructure projects 
largely occurred in the past and are localized in their effects. Since 
the Platte River caddisfly was described in 2000, there is no available 
information that suggests any habitat losses as a result of bridge 
construction, road, sandpit, or bank armoring development have 
occurred. We are not aware of planned projects within caddisfly 
habitat, and therefore we conclude that urbanization and infrastructure 
are not likely to pose threats to the Platte River caddisfly.
Livestock Grazing
    The Platte River caddisfly and its habitat could be adversely 
impacted by some cattle grazing regimes. Cattle have a strong affinity 
for riparian areas because of the availability of water, shade, and 
high-quality forage (Kauffman and Krueger 1984, p. 431). Cattle can 
impact wetlands through the reduction of vegetation cover along wetland 
bottoms and shorelines, increased sedimentation and erosion, increased 
nutrient and organic inputs from urine and manure, increased water 
temperatures, and degraded water quality, particularly when cattle have 
unrestricted access to streams (Schulz and Leininger 1990, pp. 297-298; 
Fleischner 1994, pp. 631-636; Evans and Norris 1997, p. 627; Downes et 
al. 2000, p. 569; Braccia and Voshell 2006a, p. 269; Braccia and 
Voshell 2006b, p. 2). A reduction in vegetation cover can lead to 
decreases in the inputs of coarse particulate organic matter on which 
the Platte River caddisfly feeds (Kauffman and Krueger 1984, p. 43; 
Braccia and Voshell 2006a, p. 269). Despite potential impacts, we have 
no evidence that the species is currently being adversely affected by 
cattle grazing to the point that grazing would contribute to localized 
extirpations. Cattle grazing occurs at or adjacent to 6 of 35 Platte 
River caddisfly sites, and there is no evidence of grazing occurring 
directly in the sloughs (Vivian 2010, pers. obs.). Also, Wild Rose 
Slough, which is one of the six sites where grazing occurs, supports 
the largest known caddisfly population.
    A study conducted at Wild Rose Slough to investigate the effects of 
grazing on the Platte River caddisfly found vegetation productivity to 
be lower in grazed plots than in ungrazed plots 6 months following the 
removal of cattle from the study site in spring 2010 (Harner and Geluso 
2012, p. 391). In September 2010, fewer adult caddisflies were observed 
in grazed plots than in ungrazed plots, and in 2011, lower densities of 
aquatic caddisfly larvae were found in grazed plots than in ungrazed 
plots (Harner and Geluso 2012, pp. 391-392). Meanwhile, a positive 
relationship between vegetation productivity and larval densities was 
observed (Harner and Geluso 2012, pp. 391-392).
    Results from the cattle grazing study demonstrated that although 
cattle were not allowed access to the study area in 2011, the effects 
of grazing on caddisfly larval densities could still be observed up to 
one year after grazing occurred (Harner and Geluso 2012, p. 392). These 
data also suggest that reduced vegetation cover contributed to 
decreased larval densities in intensely grazed areas within the study 
plots (Harner and Geluso 2012, p. 392). However, because larvae were 
not eliminated in grazed areas, this study demonstrates that intense 
grazing may not be detrimental to the caddisfly for short time periods 
or under a rotational grazing regime (Harner and Geluso 2012, p. 392) 
and that this species can likely withstand moderate amounts of grazing, 
particularly at sites where larval densities are relatively high. 
Continuous grazing in areas where the caddisfly is less abundant could 
contribute to localized extirpations, and the caddisfly has not been 
found at sites that show signs of intense grazing (e.g., more than 40 
percent of the bank exposed) (Braccia and Voshell 2006a, p. 271; Vivian 
2010, p. 52). However, none of the six sites with the Platte River 
caddisfly where grazing occurs show signs of overgrazing (Vivian 2010, 
pers. obs.). Therefore, we have determined that grazing is not likely 
to pose a threat to the caddisfly.
Pesticides and Herbicides
    Corn and soybean fields dominate the river valleys of Nebraska, and 
both represent potential sources of pesticide exposure to the Platte 
River caddisfly and its habitat. Should insecticides and herbicides 
enter occupied habitats of the Platte River caddisfly through runoff, 
they have the potential to directly impact the species through 
mortality or indirectly through mortality of aquatic vegetation in the 
aquatic environment (Fleeger et al. 2003, entire; Liess and Von Der Ohe 
2005, entire). Pesticides also may enter wetlands through groundwater 
inputs and could affect aquatic organisms (Spalding et al. 2003, p. 
92). Surfactants designed to facilitate pesticide and herbicide 
application have also been shown to have direct and indirect effects on 
caddisfly larvae (Belanger et al. 2000, entire; Fleeger et al. 2003, 
entire, respectively).
    There have been no studies to evaluate the potential effects of 
pesticide exposure on the Platte River caddisfly. Past studies have 
demonstrated mortality in other species of caddisflies exposed to 
pesticides (Liess and Schulz 1996, entire) and documented the absence 
of caddisflies from polluted waters (Ketelaars and Frantzen 1995, 
entire). Reduced abundances of aquatic insect species considered 
sensitive to poor water quality have been observed in habitat adjacent 
to agricultural areas (Liess and Von Der Ohe 2005, entire) that would 
presumably contain pesticide runoff.
    Aside from agricultural runoff, one potential source of herbicides 
in Platte River caddisfly habitat is chemicals used for the control of 
exotic vegetation, such as Phragmites. Because of the establishment of 
Phragmites along the Platte River, efforts have been taken to control 
the invasive vegetation using herbicide application. In 2009, the 
aquatic-safe herbicide Habitat[supreg] was sprayed in areas with 
Phragmites in the main channel of the Platte River (The

[[Page 52666]]

Nature Conservancy 2011, entire), and it is possible that drift could 
cause Habitat[supreg] to enter sloughs where the caddisfly occurs. 
Habitat[supreg] may result in lower amounts of dissolved oxygen in 
sloughs as a result of plant decomposition (BASF[supreg] 2010, entire). 
Some spraying for Phragmites occurred in 2009, during the early autumn 
when Platte River caddisfly adults are active (Vivian 2009, pers. 
obs.). Lower amounts of dissolved oxygen could impact developing 
caddisfly eggs or reduce the amount of potentially important shade 
cover in areas where willow (Salix spp.) co-occurs with Phragmites 
(Vivian 2010, pers. obs.).
    Despite potential adverse impacts to the caddisfly, there is no 
evidence that population declines or extirpations have occurred as a 
result of pesticide or herbicide exposure. Following the spraying of 
Phragmites in 2009, the Platte River caddisfly was found again at three 
of three sites where overlap between spraying and habitat occurred. 
Most Platte River caddisfly populations are also likely protected from 
pesticide or herbicide exposure by sufficient buffer strips. For 
instance, two populations located adjacent to or very near cornfields 
are likely protected from runoff by a tree and grass buffer of at least 
40 meters (131 feet), as the larval densities at these two sites are 
among the highest of known populations. The 21 populations that occur 
on protected lands are likely protected from most spray activities 
typically associated with agriculture. Furthermore, the caddisfly 
lifecycle likely protects it from some pesticide exposure, because 
larvae have been observed emigrating from the water as early as mid-
April before most crops are in the ground, and the majority of 
pesticides would enter waterways during the typical farming season in 
Nebraska of May through October.
Local Conservation Planning
    In addition to existing regulatory mechanisms and provisions 
(discussed under Factor D, below), 60 percent (21 of 35) of Platte 
River caddisfly populations occur on nongovernmental organization or 
State lands that are protected for conservation or managed as 
wilderness areas. These conservation efforts may afford protection of 
Platte River caddisfly habitat now and into the future. Such examples 
include Nebraska's Wildlife Management Areas (WMAs) and land owned and 
managed by the Headwaters Corporation, the group responsible for 
implementing and overseeing PRRIP. To date, Headwaters has been 
involved in several discussions with the Service on ways to avoid 
adverse impacts to the caddisfly with projects in and near Platte River 
caddisfly habitat. Currently, three Platte River caddisfly populations 
occur on Headwaters lands, and these sites are likely to be protected 
from future development by way of a conservation easement. Two other 
populations occur along roadsides in areas managed by the Nebraska 
Department of Roads (NDOR), and the Service works with NDOR to avoid 
and minimize impacts to wetlands on road projects.
    The Crane Trust is another entity whose lands provide protection 
for the Platte River caddisfly. The Trust manages 10,000 acres of land 
in the central Platte region that have been set aside for wildlife in 
perpetuity. Four Platte River caddisfly populations are known to occur 
on land owned by the Crane Trust, and these sites support the largest 
Platte River caddisfly larval densities currently known. In addition, 
two Platte River caddisfly populations occur on land owned by The 
Nature Conservancy (TNC), and the organization is aware of these 
populations and has taken measures to avoid adverse impacts to the 
species at these sites.
    In areas not protected for conservation, many agencies and 
organizations have been kept apprised of the Platte River caddisfly and 
have been engaged with the Service on ways to avoid and minimize 
impacts to the species and its habitat. For instance, the Federal 
Highway Administration has coordinated with the Service on ways to 
avoid and minimize impacts during a bridge reconstruction project near 
potentially suitable habitat (where the caddisfly was thought to occur) 
near Fullerton, Nebraska (Vivian 2010, pers. obs.). Also, PFW has noted 
they are willing to consider the Platte River caddisfly in their 
wetland restoration work that occurs on public and private lands 
(Schroeder 2012, pers. comm.). In 2011, PFW and TNC involved the 
Service in discussions on how to avoid adverse impacts to the caddisfly 
during restoration work at a site on TNC property. In 2010, the 
Service's Nebraska Field Office held a workshop for personnel from 
various local, State, and Federal agencies and organizations on the 
Platte River caddisfly, its habitat, and survey methodology. This 
workshop equipped agencies outside the Service with the knowledge to be 
able to avoid impacts to the caddisfly and its habitat.
    PRRIP is a program that affords the Platte River caddisfly 
protection now and into the future throughout the most degraded portion 
of its range. Objectives of PRRIP that may benefit the Platte River 
caddisfly include: (1) Preventing the need to list more basin-
associated (Platte River) species under the Act; (2) offsetting through 
mitigation any adverse impacts of new water-related activities on 
Service-targeted flows in the Platte River basin (target flows are 
comprised of species flows and annual pulse flows, which have been 
identified as flows needed to maintain survival of four target species 
and wildlife that use the Platte River, and to maintain present channel 
width and keep islands unvegetated (USDOI 2006, pp. 3-11, 3-12)); (3) 
using available resources to manage program lands for the benefit of 
non-listed species of concern, like the Platte River caddisfly; (4) 
providing sufficient water in the central Platte River (Lexington, 
Nebraska to Chapman, Nebraska) for the benefit of PRRIP's target 
species (whooping crane, Interior least tern, piping plover, pallid 
sturgeon) through water conservation projects; and (5) protecting and 
restoring 29,000 acres of habitat in the central Platte River for the 
benefit of the four target species (USDOI 2006, pp., 1-3, 1-17). This 
agreement was put in place to specifically benefit other endangered and 
threatened species, but should help maintain the backwaters where the 
Platte River caddisfly occurs, particularly through PRRIP's goal of 
maintaining current flows in the central Platte River.
    Overall, existing programs and organizations that manage land for 
conservation provide adequate protection for the species and its 
habitat. Proactive planning efforts with Federal, State, and local 
agencies, as well as nongovernmental organizations, also help to avoid 
and minimize impacts to the caddisfly.
Summary of Factor A
    Changes in hydrology resulting from water development and its 
associated effects, including channel degradation and narrowing, 
invasive species encroachment, urbanization, cropland conversion, 
groundwater withdrawal, cattle grazing, climate change, pesticides, and 
floods and droughts, all occur or are likely to occur within the range 
of the Platte River caddisfly. These environmental stressors will 
likely continue in the future on each of the river systems where the 
Platte River caddisfly is known to occur. However, while these 
stressors are ongoing, when considered individually and collectively, 
we have determined that they do not pose a threat to the Platte River 
caddisfly.
    The Platte River caddisfly has life-history traits that enable it 
to survive in an extreme environment, such as the

[[Page 52667]]

Great Plains, where climatic extremes are common. These traits are 
common among species that inhabit temporary (intermittent or ephemeral) 
wetlands and enable these species to adapt relatively quickly to 
changing conditions. The Platte River caddisfly can withstand habitat 
drying, drought, and flooding by burrowing in the soil, aestivating 
during a time when its habitat is most likely to go dry, inhabiting the 
hyporheic zone, and possibly laying its eggs in the absence of water 
(like Ironoquia punctatissima). These life history traits likely render 
the Platte River caddisfly well-suited to withstand future climatic 
changes.
    We also conclude that the aforementioned stressors do not pose a 
threat to the species, because the Platte River caddisfly occurs in 
more than one habitat type and on multiple river systems. Surveys have 
shown that the caddisfly occupies intermittent and permanent sloughs, 
forested sloughs, and sloughs with an open canopy. While the type 
locality and intermittent sloughs most likely represent ideal Platte 
River caddisfly habitat, the species is found in permanent sloughs, and 
these may be important during times of drought, as they are likely to 
hold water longer and serve as a refuge during extended dry periods. 
Forested canopies may offer an additional source of protection against 
a warmer and drier climate.
    Currently, available information does not indicate whether Platte 
River caddisfly population levels are increasing or decreasing, or if 
the amount of potential habitat is increasing or decreasing. Overall, 
we have documented that the species is more common than previously 
thought and likely is more abundant now than during the drought in the 
early 2000s. Also, an increase in surveys is likely to result in an 
increase in the known range of the caddisfly, given the amount of 
potential habitat that has yet to be surveyed. Additional survey work 
would likely result in populations being found on more river systems, 
such as the Cedar, Niobrara, and Republican Rivers in Nebraska.
    Currently, the Platte River caddisfly is known from three river 
systems, and most of the potential threats occur along the Platte 
River. Historically, the species likely occupied a much greater portion 
of the Platte River than today. However, despite all of the water 
development that has occurred on the Platte River system, the caddisfly 
still occurs along the majority of the reach surveyed between 2009 and 
2011. While ongoing degradation poses a threat to the river and the 
remaining slough habitat available to the caddisfly, several agencies 
and nongovernmental entities are working to stem future habitat losses. 
Therefore, conditions are not anticipated to deteriorate on the Platte 
River, and we consider the majority of caddisfly populations on the 
river to be secure.
    Currently, the Loup and Elkhorn Rivers have less water development 
and are less degraded than the Platte River, and the best available 
information indicates that there is sufficient habitat available 
(including sloughs not yet surveyed) to sustain the Platte River 
caddisfly on these systems. Future changes to these river systems are 
anticipated to occur through increasing sodbusting activities and 
groundwater withdrawal; however, these activities have little overlap 
with Platte River caddisfly habitat, and current laws and regulations, 
such as Nebraska State law LB 962, limit the extent to which this can 
occur.
    After a review of the best available information, we have 
determined that the present or threatened destruction, modification, or 
curtailment of its habitat or range does not pose a threat to the 
Platte River caddisfly.

Factor B. Overutilization for Commercial, Recreation, Scientific or 
Educational Purposes

    There is no indication that the Platte River caddisfly is being 
over collected by hobbyists or researchers, or will be in the future. 
Collecting of Platte River caddisfly larvae has occurred for scientific 
purposes (e.g., identification, museum archiving, lab experiments, and 
genetic analyses), but this has been limited, and largely done at sites 
supporting the greatest densities of the insect (Alexander and Whiles 
2000, p. 1; Vivian 2010, pp. 74-77; Geluso et al. 2011, p. 1022; 
Cavallaro et al. 2011, p. 5). The caddisfly is not known to have been 
collected for educational purposes.
    Insect collectors have not been known to take Platte River 
caddisfly adults for their collections, likely because caddisfly adults 
are not as showy as other groups of insects, such as butterflies. Also, 
caddisfly adults are active during a narrow window (i.e., 3 weeks), and 
the sites where the species occurs are isolated from urban areas and 
difficult to access.
Summary of Factor B
    There is no evidence that overutilization presents a threat to the 
Platte River caddisfly. Although small, isolated collections of larvae 
will likely continue for research purposes, we have determined that 
these collections do not constitute a threat to the species because, to 
date, these collections have only been conducted at sites with 
relatively high larval densities. Therefore, we conclude that the best 
scientific and commercial information available does not indicate that 
overutilization for commercial, recreational, scientific, or 
educational purposes is a threat to the Platte River caddisfly.

Factor C. Disease or Predation

    Disease and predation play important roles in the natural dynamics 
of populations and ecosystems. Natural predators of the Platte River 
caddisfly evolved in conjunction with the caddisfly and do not normally 
pose a threat to the survival of the species in the absence of other 
threats. The Platte River caddisfly could be a prey item for predators 
that are commonly observed in its habitat during its aquatic, 
terrestrial, and adult stages. Predators of caddisflies in temporary 
habitats may include large aquatic insects (dragonflies, beetles), 
amphibians (frogs, salamanders) (Batzer and Wissinger 1996, entire; 
Wellborn et al. 1996, entire), or fish, particularly in more permanent 
wetlands (Wissinger et al. 1999, entire). Aquatic insects, amphibians, 
and several fish species have all been observed at sites with the 
Platte River caddisfly, but the sand-grained case of the Platte River 
caddisfly likely offers it some protection from predators in its 
environment, as larvae in mineral cases can better withstand crushing 
than larvae in cases composed of organic material (Otto and Svensson 
1980, p. 857).
    Despite having mineral cases that can withstand crushing, the brook 
stickleback (Culaea inconstans) readily consumed Platte River caddisfly 
larvae in a laboratory setting, typically after the fish removed the 
larvae from their cases (Cavallaro 2011, pers. comm). The brook 
stickleback has been found to reduce macroinvertebrate biomass in 
wetlands in the Western Boreal Forest (Hornung and Foote 2006, entire), 
and the brook stickleback has been found at five sites with the Platte 
River caddisfly, but these sites do not support markedly lower 
densities of the Platte River caddisfly. Also, the caddisfly is well 
camouflaged in its environment, and field trials have not been 
conducted to determine if the brook stickleback consumes the Platte 
River caddisfly in its natural environment. Furthermore, the brook 
stickleback has been collected upstream and downstream of the central 
Platte River since 1942, and from the central Platte River since 1987 
and possibly earlier (Chadwick et al. 1997, p. 285), and the fish is 
considered native to

[[Page 52668]]

Nebraska (Fischer and Paukert 2008, pp. 372-373). Therefore, the 
caddisfly and stickleback have likely overlapped in their ranges prior 
to the discovery of the Platte River caddisfly, and there is no 
available information to indicate that brook sticklebacks have 
contributed, or are contributing, to localized extirpations of the 
caddisfly.
    In addition to the brook stickleback, the Platte River caddisfly 
has been found to occur with other fish predators, including the redear 
sunfish (Lepomis microlophus), fathead minnow (Pimephales promelas), 
common carp (Cyprinus carpio), and largemouth bass (Micropterus 
salmoides) (Vivian 2011, p. 14). However, there is no indication that 
these fish predators are resulting in population declines at these 
sites or that these sites support lower densities of the Platte River 
caddisfly compared to sites without these predators. Therefore, we 
conclude that predation during the aquatic stage does not pose a threat 
to the Platte River caddisfly.
    The Platte River caddisfly is likely impacted by predation in its 
terrestrial larval and adult stages. Several caddisfly cases have been 
recovered that show signs of predation possibly by ants or beetles and 
small mammals, such as shrews. Signs of predation include tears in the 
cases or holes at the posterior end of the case (Vivian 2009, pers. 
obs.). However, the sand-grained larval case likely offers some 
protection to terrestrial larvae through camouflage and defense against 
crushing (Otto and Svensson 1980, p. 857). Adults are likely eaten by 
migratory birds and waterfowl (Whiles et al. 1999, p. 543). At sites 
with relatively low numbers of caddisflies, predation on larvae in the 
terrestrial stage and adults could pose a threat to this species in the 
future. However, there is no available evidence that the predation of 
terrestrial larvae or adults is impacting populations of the Platte 
River caddisfly. Therefore, we do not consider predation during the 
terrestrial larval and adult life stages to constitute a threat to the 
species.
    Given the small number of individuals at some sites, it is possible 
that disease could pose a threat to the Platte River caddisfly. 
However, we have no evidence to suggest that any disease is currently 
affecting the Platte River caddisfly.
Summary of Factor C
    Although the Platte River caddisfly is likely a prey item for 
various predators (native and non-native), there is no evidence that 
suggests current levels of predation or disease on the Platte River 
caddisfly are currently affecting populations or will in the future. 
Therefore, we conclude that the best scientific and commercial 
information available indicates that neither disease nor predation 
poses a threat to the Platte River caddisfly.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    Existing Federal, State, and local laws; regulations; and policies 
that may provide a moderate level of protection for the Platte River 
caddisfly and its habitat include: The National Environmental Policy 
Act (NEPA; 42 U.S.C. 4321 et seq.), the Fish and Wildlife Coordination 
Act (FWCA; 16 U.S.C. 661 et seq.), section 404 of the Clean Water Act 
(CWA; 33 U.S.C. 1251 et seq.), and Nebraska State law LB 962.
    For all federally funded or authorized projects, Federal actions, 
or projects occurring on Federal lands, an Environmental Assessment or 
Environmental Impact Statement is required under NEPA. NEPA is a 
procedural statute that requires federal agencies to consider the 
environmental impacts of a proposed project and reasonable alternatives 
to project actions. It also requires full disclosure of all direct, 
indirect, and cumulative environmental impacts of the project. However, 
NEPA does not require protection of a particular species or its 
habitat, nor does it require the selection of a particular course of 
action. Therefore, NEPA may only provide a limited amount of protection 
to the caddisfly in situations where NEPA was applicable.
    NEPA does not apply to non-Federal projects on private lands or 
privately funded projects, and about 34 percent (12 of 35 sites) of the 
known populations of the Platte River caddisfly occur on private lands 
or near road ditches. Projects occurring on public hunting grounds or 
access areas, land under the management of conservation groups, and 
roadsides often receive Federal dollars, and, therefore, NEPA would 
apply to 66 percent of sites with the Platte River caddisfly. However, 
as stated above, NEPA does not provide protection to species. There is 
no available information regarding any development projects, private or 
otherwise, occurring within Platte River caddisfly habitat. Overall, we 
conclude that NEPA would provide some protection to the Platte River 
caddisfly in the event that development projects and slough habitat 
overlap in the future.
    FWCA requires that proponents of Federal water development 
projects, including those involving stream diversion, channel 
deepening, impoundment construction, and/or general modifications to 
water bodies, consider their impacts to fish and wildlife resources. 
FWCA also requires that impacts to water bodies be offset through 
mitigation measures developed in coordination with the Service and the 
appropriate State wildlife agency. FWCA would provide adequate 
protection to the Platte River caddisfly in the event that water 
development projects and Platte River caddisfly habitat overlap. 
However, there is currently no information regarding any current or 
planned water development projects within the range of the Platte River 
caddisfly. Should future water development projects occur within Platte 
River caddisfly habitat, we have determined that FWCA would adequately 
protect the caddisfly and its habitat, because the Service would be 
provided an opportunity to address potential concerns with fish and 
wildlife resources, including the caddisfly.
    The U.S. Army Corps of Engineers (Corps), acting under the 
authority of section 404 of the CWA, regulates the placement of fill 
materials into waters under Federal jurisdiction, including the filling 
of wetlands. Historically, according to a 1977 Corps definition, waters 
under Federal jurisdiction applied to ``waters of the United States,'' 
and included intermittent streams, wetlands, sloughs, prairie potholes, 
and wet meadows. This definition provided protection to nearly all 
wetlands in the United States (Petrie et al. 2001, p. 1). However, two 
Supreme Court rulings in 2001 and 2006 limited Federal authority under 
the CWA to regulate certain isolated wetlands (Solid Waste Agency of 
Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159, 
(SWANCC) (2001) and Rapanos v. United States, 547 U.S. 715 (2006)). 
Following the SWANCC and Rapanos decisions, it was unknown how the 
Corps would interpret its jurisdictional lines (Petrie et al. 2001, p. 
3). According to 2008 guidance documents of the Corps and Environmental 
Protection Agency, the CWA applies to wetlands adjacent to navigable 
waters of the United States. This means wetlands must have an unbroken 
surface or shallow sub-surface connection to jurisdictional waters 
(even if the connection is intermittent), be physically separated from 
jurisdictional waters by manmade dikes or barriers or natural river 
berms, or be in close proximity to navigable waters, supporting the 
science-based inference that such wetlands have an ecological 
interconnection with jurisdictional waters.
    Currently, most Corps permit applications in central Nebraska are 
for

[[Page 52669]]

restoration work along the Platte River by groups such as the PFW, 
NGPC, and Ducks Unlimited (Moeschen 2011, pers. comm.). Typically, the 
Service is made aware of these projects and has educated restoration 
proponents on the Platte River caddisfly and its habitat so as to avoid 
potential adverse impacts to extant populations. Also, sand and gravel 
mining operations, if occurring within wetlands along the river, would 
require a Corps permit. A Corps permit would provide the Service with 
adequate opportunity to address concerns regarding fish and wildlife 
resources, and any issued permit would require mitigation (offset 
impacts, restore area of equal habitat value) at a minimum ratio of 1:1 
(Corps 2005, p. 18). Furthermore, the Corps has been kept apprised of 
all sites where the caddisfly occurs, and two Corps representatives 
attended a workshop in 2010 that educated various agency personnel on 
the Platte River caddisfly and its habitat.
    Most sloughs that support a Platte River caddisfly population occur 
in areas directly connected to or adjacent to the main channel of the 
Platte, Loup, and Elkhorn Rivers. Adjacency under CWA is easily 
determined for these sloughs. Four of the 35 sites occur in more off-
channel areas, and adjacency for these sloughs may not be as easily 
determined. Despite occurring in more off-channel areas, these four 
sloughs still likely receive protection from fill. For instance, two 
sites on the Elkhorn River occur along roadsides, and FHWA and the 
Nebraska Department of Roads notifies the Service when work within or 
near wetland areas is scheduled to occur. If these areas become subject 
to fill activities in the future, the Service would have an opportunity 
to recommend ways to avoid and minimize impacts to the wetlands. 
Meanwhile, Wild Rose Slough and the type locality on Crane Trust 
property are protected from fill activities by way of a conservation 
easement. Overall, 23 of 35 caddisfly populations occur within WMAs or 
lands managed for conservation or roadsides and are protected from most 
fill and development activities in wetlands (with the exception of 
restoration work). Thus, the CWA adequately protects the Platte River 
caddisfly and its habitat from fill and development activities now and 
into the future, because: (1) The CWA would apply to the majority of 
populations should such activities occur in the future; (2) 66 percent 
of populations occur in protected areas; and (3) the Service and Corps 
have engaged in proactive planning efforts so as to avoid impact to the 
caddisfly and its habitat.
    Several governmental and nongovernmental agencies are working to 
secure water rights for environmental benefits and endangered and 
threatened species in Nebraska; however, instream flow appropriations 
do not ensure a stream will always contain water (Czaplewski 2009, 
entire). Instream appropriations only ensure that the minimum flow 
needs of species will be met before any future water development 
projects can occur (Czaplewski 2009, entire). Therefore, in times of 
drought and low flows, pre-existing water rights will be met before the 
minimum flow needs of fish and wildlife species are met. However, we 
previously determined that the Platte River caddisfly can withstand 
drought to a certain degree even when coupled with existing water 
development projects.
    The Central Platte Natural Resources District (CPNRD) and NGPC each 
have protected instream flow rights along the Platte River; however, 
these are not enough to cover ``target flows'' outlined by the PRRIP 
(NGPC 2008, p. 7). The PRRIP is working to address shortages to target 
flows by managing an environmental account from reservoirs along the 
Platte River in Nebraska and leasing water rights from willing 
landowners. The PRRIP also has a goal of offsetting new depletions to 
the system that occurred after July 1997 and restoring flows to the 
river by 130,000 to 150,000 acre-feet per year between 2007 and 2019. 
Efforts to augment current Platte River flows should provide adequate 
protection for the Platte River caddisfly populations along the Platte 
River, possibly with the exception of the type locality and Wild Rose 
Slough. For instance, as discussed under Factor A, even with more water 
in the river channel, the type locality and Wild Rose Slough may not 
become inundated or remain inundated long enough to meet the needs of 
the Platte River caddisfly (Harner and Whited 2011, entire). 
Furthermore, the PRRIP seeks to augment sediment inputs to the central 
Platte River, which should also help prevent future channel degradation 
from impacting sloughs where the caddisfly occurs.
    Passed in 2004, Nebraska State law LB 962 requires the Nebraska 
Department of Natural Resources to work with each of the 23 Nebraska 
Natural Resource Districts (NRDs) to address surface water and 
groundwater appropriations in fully or over-appropriated basins. Basins 
designated as fully appropriated are required to place a moratorium on 
any new groundwater wells until an integrated management plan to 
address depletion issues can be developed (NGPC 2008, p. 18). The law 
does not prevent new groundwater wells from being drilled outside fully 
appropriated basins, such as some areas on the Loup River. Future 
groundwater well construction could contribute to some future loss in 
slough habitat on the Loup and Elkhorn Rivers as has been observed on 
the Platte, leading to future caddisfly habitat loss. However, we 
estimate that the amount of habitat that could be impacted is small, 
because new development is done on a limited basis, and each NRD 
monitors groundwater and stream levels annually to ensure water 
resources are not being depleted.
Summary of Factor D
    Given that 66 percent of Platte River caddisfly populations occur 
on protected lands, and current laws and regulations provide adequate 
protection for slough habitat on private lands should future activities 
occur within slough habitat, we conclude that the inadequacy of 
existing regulatory mechanisms does not pose a threat to the Platte 
River caddisfly.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

Small Population Size
    Small insect populations may be vulnerable to extirpation as a 
result of random genetic drift, naturally occurring stochastic events, 
or demographic stochasticity (Pimm et al. 1988, p. 757; Boyce 1992, p. 
482; Purvis et al. 2000, p. 1949; Melbourne and Hastings 2008, p. 3). 
Extinction of small populations is also likely to happen more quickly 
than extinction of larger populations due to inbreeding (Brook et al. 
2002, pp. 3-4), and this could affect the Platte River caddisfly in the 
future.
    We do not know the true population size of any of the known Platte 
River caddisfly populations, but we do have information on the numbers 
of individuals at 18 sites with the caddisfly. We previously discussed 
that some sites support relatively low densities of the Platte River 
caddisfly, but determined that finding low numbers of individuals at a 
site is typical of the Ironoquia genus. We also determined that varying 
population levels across the range of the Platte River caddisfly likely 
represent the norm for the species, and varying population densities 
are likely a product of the species occurring in more than one type of 
habitat. Also, because of various life history traits that enable the

[[Page 52670]]

caddisfly to survive in temporary habitats, the caddisfly is more able 
to withstand stochastic events than species less tolerant of extreme 
weather events. Therefore, we have determined that small population 
size does not pose a threat to the caddisfly.
Limited Dispersal Ability
    The adult stage likely represents the most probable means of 
dispersal (Williams 1996, p. 644; Petersen et al. 2004, p. 934) for the 
Platte River caddisfly. Poor adult flight capabilities and a short 
window of adult activity indicate that Platte River caddisfly dispersal 
to new habitats and between populations is likely a rare event. 
Observations when adults are active have found individuals underneath 
vegetation and on or near the ground, particularly when it is windy, 
and above vegetation or immediately adjacent to standing water in 
slough habitat during more favorable weather conditions (Vivian 2009, 
pers. obs.; Vivian 2010, pers. obs.; Geluso et al. 2011, p. 1024). When 
active, the caddisfly has only once been observed to fly more than 10 
meters, and wind seemed to greatly influence that individual (Vivian 
2009, pers. obs.; Vivian 2010, pers. obs.). Platte River caddisfly 
adults are also active for a short period of time (i.e., about 2 to 3 
weeks) (Whiles et al. 1999, p. 539; Goldowitz 2004, p. 6), and this 
likely limits the species' dispersal ability compared to other 
caddisflies with longer adult lifespans (Svensson 1972; entire) and 
could reduce the amount of genetic variability within populations.
    Genetics techniques can be used to assess a species' dispersal 
ability in the absence of direct observations of significant dispersal 
events (Kelly et al. 2002, p. 1642). Amplified Fragment Length 
Polymorphism has been used to determine the amount of genetic 
similarity among five caddisfly populations from the Platte, Loup, and 
Elkhorn Rivers (Cavallaro et al. 2011, entire). It was found that one 
Platte River caddisfly population from near Sutherland, Nebraska, and 
one near Kearney, Nebraska, had more genetic similarity to each other 
than the population near Kearney did to a population near Gibbon, 
Nebraska, despite the closer proximity of Kearney and Gibbon. Also, the 
population near Gibbon was found to be more closely related to the 
population near Loup City, Nebraska, even though Loup City is farther 
from Gibbon than Kearney (~21 km or 13.1 mi) (Bunn and Hughes 1997, p. 
341; Cavallaro et al. 2011, pp. 12, 15). The Elkhorn River population 
tested was found to be the most dissimilar from all other populations 
(Cavallaro et al. 2011, p. 7), but this may be more a product of 
geographic isolation as opposed to habitat fragmentation. It was also 
established that there is a low amount of gene flow among existing 
Platte River caddisfly populations and more intra-population variation 
than inter-population variation (Cavallaro et al. 2011, pp. 6-7).
    The amount of genetic variability observed in the Platte River 
caddisfly (Cavallaro et al. 2011, p. 7) is similar to what has been 
observed in the caddisfly Wormaldia tagananana, which is identified as 
having a limited range and presumed limited dispersal ability (Kelly et 
al. 2002, p. 1646). Low gene flow between Platte River caddisfly 
populations further corroborates that the caddisfly has a limited 
ability to disperse to new habitats (e.g., restored sloughs, sites that 
were previously extirpated), and that successful dispersal to new 
habitats likely depends upon just a few individuals (Schmidt et al. 
1995, p. 154; Cavallaro et al. 2011, pp. 6-7).
    Although it has been identified that the Platte River caddisfly is 
a poor disperser, this is a natural life-history trait. This behavior 
would be detrimental to the species if the existing populations 
remained isolated from one another. However, we have not identified 
that habitat loss is presently occurring to the extent that the 
fragmentation of Platte River caddisfly populations poses a threat to 
the species. While sloughs on the different river systems and on both 
sides of the 155-km (93-mi) distribution gap between Hershey and Elm 
Creek, Nebraska, are isolated from one another, there is evidence of 
gamete (male and female reproductive cells) exchange across river 
systems given the similarity between the sites near Gibbon and Loup 
City and between Kearney and Sutherland. Furthermore, there have been 
live individuals or cases found at two restored sites. These 
observations indicate that there is a limited amount of dispersal 
occurring within relatively short time periods across short distances.
Summary of Factor E
    In summary, although small population size and limited dispersal 
ability have the potential to adversely impact the Platte River 
caddisfly, there is no evidence that this is occurring or is likely to 
occur in the near future. For instance, there are no known caddisfly 
population extirpations that have occurred as a result of small 
population size. We previously established that the Platte River 
caddisfly has the ability to recolonize sloughs following stochastic 
events and is well adapted to the environmental extremes found in the 
Great Plains. Therefore, we conclude that other natural or manmade 
factors do not pose a threat to the species.
Cumulative Impacts
    Some of the threats discussed in this finding can work in concert 
with one another to cumulatively create situations that will impact the 
Platte River caddisfly beyond the scope of each individual threat. For 
example, as mentioned under Factor A, the impacts of water development 
on Platte River caddisfly habitat could be exacerbated by the effects 
of drought and the projected increases in drought resulting from 
climate change. In the absence of water development projects across the 
landscape, the Platte River caddisfly is naturally tolerant of drought 
because of its semi-terrestrial lifecycle and ability to recolonize 
sloughs once they become inundated again following extended dry 
periods. However, in the presence of water development, projects that 
remove water from the Platte, Loup, and Elkhorn Rivers have the 
potential to reduce the amount of available habitat across the 
landscape to the point that, during drought, enough refugia may not be 
available to sustain existing populations. Also, because of climate 
change, the frequency of droughts is expected to increase, and this 
will likely be exacerbated by ongoing water development. Water 
development has the ability to exacerbate the effects of drought 
(climate change-related or otherwise), because less water is flowing 
through the system than what there would be in the absence of water 
development. Future, extreme droughts and climate change are also 
expected to facilitate the spread of non-native vegetation, and this 
could result in a loss in habitat due to the encroachment of exotic 
vegetation in sloughs. Because of these relationships, we will analyze 
the cumulative impact of drought (as a result of climate change), water 
development (human-caused water reduction), and invasive species.

Water Development, Drought, and Invasive Species

    As mentioned previously, under normal conditions and otherwise, the 
Platte River caddisfly has the ability to withstand drought, because it 
enters into a dormant phase during the typical summer dry period. 
However, extreme drought can adversely impact the caddisfly to the 
point that it results in localized extirpations. For instance, extreme 
drought resulted in the extirpation of the type locality and one

[[Page 52671]]

site near Shelton, Nebraska, in the early 2000s. The species has since 
recolonized the type locality. The Shelton site has not been surveyed 
since 2009, but it is possible the Platte River caddisfly has 
recolonized this area. This indicates that there was likely sufficient 
habitat available near the type locality during the drought to serve as 
refugia for the caddisfly, and that within a short period of time 
following disturbance, the species founded new populations in 
previously occupied habitat.
    The drought in the early 2000s occurred during a time when water 
development projects, such as dams and diversions, were prevalent 
across the landscape, particularly along the Platte River. The Platte 
River is considered to be the most degraded portion of the range of the 
caddisfly, but no new, large water projects have been implemented since 
1956. Under current laws and regulations, we anticipate that current 
conditions with respect to water development are not anticipated to 
deteriorate along the Platte River or appreciably diminish on the Loup 
and Elkhorn Rivers.
    The caddisfly has already been shown to withstand the combined 
effects of extreme drought and water-related impacts to its habitat. 
The species is also still present following the proliferation of 
invasive species along the Platte River during the drought in the early 
2000s. Meanwhile, there are no new, large-scale water development 
projects planned within the range of the caddisfly. Therefore, the 
amount of habitat available to the caddisfly is not anticipated to 
greatly diminish because of water development now or into the future. 
While future, extreme droughts could result in extirpations of the 
caddisfly at a local scale, from examining satellite imagery to 
identify slough habitat, we find there is sufficient habitat available 
surrounding current populations to serve as refugia for the species 
during drought. Thus, there is no information to suggest that future, 
extreme droughts resulting from climate change and current water 
development projects will reduce the ability of existing caddisfly 
populations to sustain themselves under a warmer and drier climate.
    We previously identified that at three Platte River caddisfly sites 
along the Platte River, Phalaris arundinacea (reed canarygrass) may 
encroach enough in the future to contribute to the extirpation of the 
caddisfly at these locations. There is no evidence that suggests 
Phalaris arundinacea is resulting in habitat loss at the remaining 32 
sites where the species occurs. Because of the current small number of 
sites affected by invasive species (3 of 35), and our inability to 
predict the future effects of invasive species on other caddisfly 
sites, we do not find that invasive species pose a threat to the 
species now or in the future.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the Platte River caddisfly is endangered or threatened 
throughout all of its range. We examined the best scientific and 
commercial information available regarding the past, present, and 
future threats faced by the Platte River caddisfly. We reviewed the 
petition, information available in our files, other available published 
and unpublished information, and we consulted with recognized 
caddisfly, slough, and hydrology experts and other Federal, State, and 
nongovernmental entities. On the basis of the best scientific and 
commercial information available, we find that the Platte River 
caddisfly is not in danger of extinction (endangered species) now or 
likely to become an endangered species within the foreseeable future 
(threatened species), throughout all or a significant portion of its 
range. Therefore, we find that listing the Platte River caddisfly as an 
endangered or threatened species is not warranted throughout its range 
at this time.
    The Platte River caddisfly is currently known from 35 locations 
across three river systems, and the number of populations would most 
likely increase with additional survey efforts, because potentially 
suitable habitat has been identified but has not been surveyed. 
Meanwhile, with the exception of the type locality, there is a lack of 
information on population trends. It appears that the caddisfly 
naturally occurs at varying densities depending on habitat type and may 
even be classified as a habitat generalist. Because the species occurs 
in more than one habitat type on three different river systems, the 
caddisfly is well-represented across the landscape and is resilient to 
the various stressors present throughout its range.
    In this finding, we identified a number of potential stressors 
under Factor A. The stressor most likely to constitute a threat to the 
Platte River caddisfly and its habitat in the future is landscape-level 
changes in hydrology. The Platte River is one of the most managed river 
systems in the United States and contains several impoundments, 
diversions, and groundwater withdrawals that have resulted in 
hydrological and morphological changes to the floodplain. The 
dewatering of the Platte River likely resulted in historical losses of 
Platte River caddisfly habitat. Nonetheless, we have established that 
most remaining populations are likely to remain adequately protected 
across this portion of the species' range because of programs, such as 
PRRIP and PFW, and the existence of protected areas where many Platte 
River caddisfly populations occur. Although ongoing and future Platte 
River channel degradation could potentially affect the Platte River 
caddisfly and its habitat in the future, particularly at the Crane 
Trust, restoration efforts are ongoing along the central Platte River 
to stem this trend. These efforts should protect caddisfly populations 
along the Platte River, where most stressors are concentrated, now and 
into the future.
    Climate change is a concern and is likely to render the range of 
the Platte River caddisfly hotter and drier. Nonetheless, we have 
determined that the species should withstand future climatic changes 
because of various life-history traits that are common among semi-
terrestrial caddisflies and because of the distribution of its habitat 
across the landscape. We have determined that the present or threatened 
destruction, modification, or curtailment of its habitat or range 
(Factor A) is not a threat to the Platte River caddisfly at this time.
    We have determined that overutilization for commercial, 
recreational, or scientific use (Factor B) is not a threat to the 
species at this time. Neither disease nor predation (Factor C) is known 
or expected to be a threat to the species. We have determined that the 
inadequacy of existing regulatory mechanisms (Factor D) is not a threat 
to the Platte River caddisfly, and that regulatory mechanisms currently 
in place provide protection to the species. Regarding other natural or 
manmade factors affecting its continued existence (Factor E), we do not 
consider small population size or limited dispersal ability to 
constitute a threat to the species. The available information does not 
indicate that the caddisfly is being impacted genetically, or in any 
other way, as a result of small population size or limited dispersal 
ability, or that it will become an endangered or threatened species in 
the foreseeable future due to stochastic events. We have also examined 
the cumulative impact of various stressors acting together and whether 
those pose a threat to the caddisfly. We have determined that, when 
examined together, the cumulative impact of various stressors does not 
pose a threat to the caddisfly.

[[Page 52672]]

Significant Portion of the Range

    Having determined that the Platte River caddisfly is not an 
endangered or threatened species throughout its range, we must next 
consider whether there are any significant portions of its range where 
the species is in danger of extinction or is likely to become an 
endangered species in the foreseeable future. The Act defines 
``endangered species'' as any species which is ``in danger of 
extinction throughout all or a significant portion of its range,'' and 
``threatened species'' as any species which is ``likely to become an 
endangered species within the foreseeable future throughout all or a 
significant portion of its range.'' The phrase ``significant portion of 
its range'' (SPR) is not defined by the statute, and we have no 
regulation governing SPR.
    We interpret the phrase ``significant portion of its range'' in the 
Act's definitions of ``endangered species'' and ``threatened species'' 
to provide an independent basis for listing; thus, there are two 
situations (or factual bases) under which a species would qualify for 
listing: A species may be an endangered or threatened species 
throughout all of its range; or a species may be an endangered or 
threatened species in only a significant portion of its range. If a 
species is in danger of extinction throughout an SPR, the species is an 
``endangered species.'' The same analysis applies to ``threatened 
species.'' Based on this interpretation and supported by existing case 
law, the consequence of finding that a species is an endangered or 
threatened species in only a significant portion of its range is that 
the entire species will be listed as an endangered or threatened 
species, respectively, and the Act's protections will be applied across 
the species' entire range. Because ``significant portion of its range'' 
provides an independent basis for listing and protecting the entire 
species, we next turn to the meaning of ``significant'' to determine 
the threshold for when such an independent basis for listing exists.
    Although there are potentially many ways to determine whether a 
portion of a species' range is ``significant,'' the significance of the 
portion of the range should be determined based on its biological 
contribution to the conservation of the species. For this reason, we 
describe the threshold for ``significant'' in terms of an increase in 
the risk of extinction for the species. We conclude that a biologically 
based definition of ``significant'' best conforms to the purposes of 
the Act, is consistent with judicial interpretations, and best ensures 
species' conservation. Thus, as explained further below, a portion of 
the range of a species is ``significant'' if its contribution to the 
viability of the species is so important that without that portion, the 
species would be in danger of extinction.
    We evaluate biological significance based on the principles of 
conservation biology using the concepts of redundancy, resiliency, and 
representation. Resiliency describes the characteristics of a species 
and its habitat that allow it to recover from periodic disturbance. 
Redundancy (having multiple populations distributed across the 
landscape) may be needed to provide a margin of safety for the species 
to withstand catastrophic events. Representation (the range of 
variation found in a species) ensures that the species' adaptive 
capabilities are conserved. Redundancy, resiliency, and representation 
are not independent of each other, and some characteristic of a species 
or area may contribute to all three. For example, distribution across a 
wide variety of habitat types is an indicator of representation, but it 
may also may indicate a broad geographic distribution contributing to 
redundancy (decreasing the chance that any one event affects the entire 
species), and the likelihood that some habitat types are less 
susceptible to certain threats, contributing to resiliency (the ability 
of the species to recover from disturbance). None of these concepts is 
intended to be mutually exclusive, and a portion of a species' range 
may be determined to be ``significant'' due to its contributions under 
any one or more of these concepts.
    We determine if a portion's biological contribution is so important 
that the portion qualifies as ``significant'' by asking whether without 
that portion, the representation, redundancy, or resiliency of the 
species would be so impaired that the species would have an increased 
vulnerability to threats to the point that the overall species would be 
in danger of extinction (i.e., would be ``an endangered species''). 
Conversely, we would not consider the portion of the range at issue to 
be ``significant'' if there is sufficient resiliency, redundancy, and 
representation elsewhere in the species' range that the species would 
not be in danger of extinction throughout its range if the population 
in that portion of the range in question became extirpated (extinct 
locally).
    We recognize that this definition of ``significant'' (a portion of 
the range of a species is ``significant'' if its contribution to the 
viability of the species is so important that without that portion, the 
species would be in danger of extinction) establishes a threshold that 
is relatively high. On the one hand, given that the consequences of 
finding a species to be an endangered or threatened species in an SPR 
would be listing the species throughout its entire range, it is 
important to use a threshold for ``significant'' that is robust. It 
would not be meaningful or appropriate to establish a very low 
threshold whereby a portion of the range can be considered 
``significant'' even if only a negligible increase in extinction risk 
would result from its loss. Because nearly any portion of a species' 
range can be said to contribute some increment to a species' viability, 
use of such a low threshold would require us to impose restrictions and 
expend conservation resources disproportionately to achieve 
conservation benefits. This would result in the listing being 
rangewide, even if only a portion of the range of minor conservation 
importance to the species is imperiled. On the other hand, it would be 
inappropriate to establish a threshold for ``significant'' that is too 
high. This would be the case if the standard were, for example, that a 
portion of the range can be considered ``significant'' only if threats 
in that portion result in the entire species' being currently 
endangered or threatened. Such a high bar would not give the SPR phrase 
independent meaning, as the Ninth Circuit held in Defenders of Wildlife 
v. Norton, 258 F.3d 1136 (9th Cir. 2001).
    The definition of ``significant'' used in this finding carefully 
balances these concerns. By setting a relatively high threshold, we 
minimize the degree to which restrictions will be imposed or resources 
expended that do not contribute substantially to species conservation. 
But we have not set the threshold so high that the phrase ``in a 
significant portion of its range'' loses independent meaning. 
Specifically, we have not set the threshold as high as it was under the 
interpretation presented by the Service in the Defenders litigation. 
Under that interpretation, the portion of the range would have to be so 
important that current imperilment there would mean that the species 
would be currently imperiled everywhere. Under the definition of 
``significant,'' the portion of the range need not rise to such an 
exceptionally high level of biological significance. (We recognize that 
if the species is imperiled in a portion that rises to that level of 
biological significance, then we should conclude that the species is in 
fact imperiled throughout all of its range, and that we would not need 
to rely on the SPR language for such a listing.)

[[Page 52673]]

Rather, under this interpretation we ask whether the species would be 
an endangered species everywhere without that portion, i.e., if that 
portion were completely extirpated. In other words, the portion of the 
range need not be so important that even the species being in danger of 
extinction in that portion would be sufficient to cause the species in 
the remainder of the range to be an endangered species; rather, the 
complete extirpation (in a hypothetical future) of the species in that 
portion would be required to cause the species in the remainder of the 
range to be an endangered species.
    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 have no reasonable potential to be 
significant or to analyzing portions of the range in which there is no 
reasonable potential for the species to be an endangered or threatened 
species. 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. Depending on the biology of the species, 
its range, and the threats it faces, it might be more efficient for us 
to address the significance 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 an 
endangered or threatened species 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.'' In 
practice, a key part of the determination that a species is in danger 
of extinction in a significant portion of its range 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 to the species occurs only in portions of the species' range 
that clearly would not meet the biologically based definition of 
``significant,'' such portions will not warrant further consideration.
    To determine whether the Platte River caddisfly could be considered 
an endangered or threatened species in a ``significant portion of its 
range'', we reviewed the best scientific information with respect to 
the geographic concentration of threats and the significance of 
portions of the range to the conservation of the species. We first 
evaluated whether substantial information indicated (i) the threats are 
so concentrated in any portion of the species' range that the species 
may be currently in danger of extinction in that portion; and (ii) if 
so, whether those portions may be significant to the conservation of 
the species. Our rangewide review of the species concluded that the 
Platte River caddisfly is not an endangered or threatened species. As 
described above, to establish whether any areas may warrant further 
consideration, we reviewed our analysis of the five listing factors to 
determine whether any of the potential threats identified were so 
concentrated among the 35 populations that some portion of the range of 
the Platte River caddisfly may be in danger of extinction now or in the 
foreseeable future.
    We found that most potential threats evaluated in this rule were 
concentrated on the Platte River, and we have determined that these 
potential threats, including but not limited to: landscape level 
changes in hydrology, invasive species, climate change, drought, 
flooding, grazing, inadequacy of existing regulatory mechanisms, and 
poor dispersal ability, are not resulting in current losses of slough 
habitat or losses of any of the 28 populations of the Platte River 
caddisfly along the Platte River, nor are they likely to do so in the 
foreseeable future. In addition, we find that the Platte River portion 
of the range of the caddisfly is not endangered or threatened because 
of existing programs and entities that are striving to protect current 
channel conditions. There is also no information to indicate that the 
potential threats analyzed under the five factors are contributing to a 
decline in the number of Platte River caddisfly populations or amount 
of slough habitat available along the central Platte River. For 
instance, we analyzed projected increases in the frequency of droughts 
in central Nebraska and how this could impact the Platte River 
caddisfly and its habitat. We also considered how the effects of 
climate change may be compounded by current levels of water development 
and have determined that these threats are not likely to pose a threat 
to the Platte River caddisfly across its range. Therefore, based on our 
review, the available information does not indicate that any of the 
potential threats we evaluated in all the factors under the Act were so 
concentrated in any portion of the species' range as to find that the 
Platte River caddisfly may currently be in danger of extinction in that 
portion of its range. Because we find that the Platte River caddisfly 
is not an endangered species in any portion of its range now or in the 
foreseeable future, we need not address the question of whether any 
portion may be significant.

Conclusion

    Our review of the information pertaining to the five factors does 
not support the assertion that there are threats acting on the species 
or its habitat that have rendered the Platte River caddisfly to be in 
danger of extinction or likely to become so in the foreseeable future, 
throughout all or a significant portion of its range. Therefore, 
listing the Platte River caddisfly as an endangered or threatened 
species under the Act is not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, the Platte River caddisfly to our Nebraska 
Field Office (see ADDRESSES) whenever it becomes available. New 
information will help us monitor the Platte River caddisfly and 
encourage its conservation. If an emergency situation develops for the 
Platte River caddisfly or any other species, we will act to provide 
immediate protection.

References Cited

    A complete list of references cited is available on the Internet at 
https://www.regulations.gov and upon request from the Nebraska Field 
Office (see ADDRESSES).

Authors

    The primary authors of this notice are the staff members of the 
Nebraska Field Office.

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: August 20, 2012.
 Benjamin N. Tuggle,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2012-21352 Filed 8-29-12; 8:45 am]
BILLING CODE 4310-55-P