Endangered and Threatened Wildlife and Plants; Reclassifying the Tobusch Fishhook Cactus From Endangered to Threatened on the Federal List of Endangered and Threatened Plants, 95932-95941 [2016-31296]
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Federal Register / Vol. 81, No. 250 / Thursday, December 29, 2016 / Proposed Rules
plant occurs on the date on which all
Federal, state, local, and contractual
decommissioning requirements are fully
satisfied (the substantial completion
date). Except as otherwise provided in
paragraph (d)(3)(ii) of this section, the
substantial completion date is also the
termination date.
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*
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John Dalrymple,
Deputy Commissioner for Services and
Enforcement.
[FR Doc. 2016–31205 Filed 12–28–16; 8:45 am]
BILLING CODE 4830–01–P
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS–R2–ES–2016–0130;
FXES11130900000 178 FF09E42000]
RIN 1018–BB90
Endangered and Threatened Wildlife
and Plants; Reclassifying the Tobusch
Fishhook Cactus From Endangered to
Threatened on the Federal List of
Endangered and Threatened Plants
Fish and Wildlife Service,
Interior.
ACTION: Proposed rule and 12-month
petition finding; request for comments.
AGENCY:
Under the authority of the
Endangered Species Act of 1973, as
amended (Act), we, the U.S. Fish and
Wildlife Service (Service), propose to
reclassify the Tobusch fishhook cactus
(Sclerocactus brevihamatus ssp.
tobuschii; currently listed as
Ancistrocactus tobuschii) from
endangered to threatened on the Federal
List of Endangered and Threatened
Plants (List). This determination is
based on a thorough review of the best
available scientific and commercial
information, which indicates that the
threats to this plant have been reduced
to the point that it no longer meets the
definition of endangered under the Act,
but may still become endangered within
the foreseeable future. This document
also serves as the 12-month finding on
a petition to reclassify this plant from
endangered to threatened.
DATES: We will accept comments
received or postmarked on or before
February 27, 2017. Please note that if
you are using the Federal eRulemaking
Portal (see ADDRESSES), the deadline for
submitting an electronic comment is
11:59 p.m. Eastern Time on this date.
We must receive requests for public
hearings, in writing, at the address
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SUMMARY:
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shown in FOR FURTHER INFORMATION
by February 13, 2017.
ADDRESSES: Written comments: You may
submit comments by one of the
following methods:
(1) Electronically: Go to the Federal
eRulemaking Portal: https://
www.regulations.gov. In the Search box,
enter FWS–R2–ES–2016–0130, which is
the docket number for this rulemaking.
Then, click on the Search button. On the
resulting page, in the Search panel on
the left side of the screen, under the
Document Type heading, click on the
Proposed Rules link to locate this
document. You may submit a comment
by clicking on ‘‘Comment Now!’’
(2) By hard copy: Submit by U.S. mail
or hand-delivery to: Public Comments
Processing, Attn: FWS–R2–ES–2016–
0130, U.S. Fish and Wildlife Service,
MS: BPHC, 5275 Leesburg Pike, Falls
Church, VA 22041–3803.
We request that you send comments
only by the methods described above.
We will post all comments on https://
www.regulations.gov. This generally
means that we will post any personal
information you provide us (see Public
Comments, below, for more
information).
Copies of Documents: This proposed
rule and supporting documents are
available on https://www.regulations.gov.
In addition, the supporting file for this
proposed rule will be available for
public inspection, by appointment,
during normal business hours, at the
Austin Ecological Services Field Office,
10711 Burnet Rd., Suite 200, Austin, TX
78727; telephone 512–490–0057.
FOR FURTHER INFORMATION CONTACT:
Adam Zerrenner, Field Supervisor, U.S.
Fish and Wildlife Service, Austin
Ecological Services Field Office, 10711
Burnet Rd., Suite 200, Austin, TX
78727; telephone 512–490–0057; or
facsimile 512–490–0974. Persons who
use a telecommunications device for the
deaf (TDD) may call the Federal
Information Relay Service (FIRS) at
800–877–8339.
SUPPLEMENTARY INFORMATION:
CONTACT
Information Requested
Public Comments
We want any final rule resulting from
this proposal to be as effective as
possible. Therefore, we invite tribal and
governmental agencies, the scientific
community, industry, and other
interested parties to submit comments
or recommendations concerning any
aspect of this proposed rule. Comments
should be as specific as possible.
To issue a final rule to implement this
proposed action, we will take into
consideration all comments and any
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additional information we receive. Such
communications may lead to a final rule
that differs from this proposal. All
comments, including commenters’
names and addresses, if provided to us,
will become part of the supporting
record.
We are specifically requesting
comments on:
(1) New information on the historical
and current status, range, distribution,
and population size of the Tobusch
fishhook cactus, including the locations
of any additional populations.
(2) New information on the known
and potential threats to the Tobusch
fishhook cactus.
(3) New information regarding the life
history, ecology, and habitat use of the
Tobusch fishhook cactus.
Please note that submissions merely
stating support for or opposition to the
action under consideration without
providing supporting information,
although noted, will not be considered
in making a determination, as section
4(b)(1)(A) of the Act (16 U.S.C. 1531 et
seq.) directs that determinations as to
whether any species is an endangered or
threatened species must be made
‘‘solely on the basis of the best scientific
and commercial data available.’’
You may submit your comments and
materials concerning the proposed rule
by one of the methods listed in
ADDRESSES. Comments must be
submitted to https://www.regulations.gov
before 11:59 p.m. (Eastern Time) on the
date specified in DATES. We will not
consider hand-delivered comments that
we do not receive, or mailed comments
that are not postmarked, by the date
specified in DATES.
We will post your entire comment—
including your personal identifying
information—on https://
www.regulations.gov. If you provide
personal identifying information in your
comment, you may request at the top of
your document that we withhold this
information from public review.
However, we cannot guarantee that we
will be able to do so.
Comments and materials we receive,
as well as supporting documentation we
used in preparing this proposed rule,
will be available for public inspection
on https://www.regulations.gov, or by
appointment, during normal business
hours at the U.S. Fish and Wildlife
Service, Austin Ecological Services
Field Office (see FOR FURTHER
INFORMATION CONTACT).
Public Hearing
Section 4(b)(5)(E) of the Act provides
for one or more public hearings on this
proposed rule, if requested. We must
receive requests for public hearings, in
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writing, at the address shown in FOR
FURTHER INFORMATION CONTACT by the
date shown in DATES. We will schedule
public hearings on this proposal, if any
are requested, and places of those
hearings, as well as how to obtain
reasonable accommodations, in the
Federal Register at least 15 days before
the first hearing.
asabaliauskas on DSK3SPTVN1PROD with PROPOSALS
Peer Review
In accordance with our policy,
‘‘Notice of Interagency Cooperative
Policy for Peer Review in Endangered
Species Act Activities,’’ which was
published on July 1, 1994 (59 FR
34270), we are soliciting the expert
opinion of at least three appropriate
independent specialists regarding
scientific data and interpretations
contained in the Species Status
Assessment Report (SSA Report)
(Service 2016; available at https://
www.regulations.gov under Docket No.
FWS–R2–ES–2016–0130) supporting
this proposed rule. The purpose of such
review is to ensure that our decisions
are based on scientifically sound data,
assumptions, and analysis. We will
incorporate, as appropriate, the
feedback from the peer review of the
SSA Report into any final determination
regarding the subspecies.
Background
Section 4(b)(3)(B) of the Act 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
reclassifying a species may be
warranted, we make a finding within 12
months of the date of receipt of the
petition (‘‘12-month finding’’). In this
finding, we determine whether the
petitioned action is: (1) Not warranted,
(2) warranted, or (3) warranted, but
immediate proposal of a regulation
implementing the petitioned action is
precluded by other pending proposals to
determine whether species are
endangered or threatened, and
expeditious progress is being made to
add or remove qualified species from
the Federal Lists of Endangered and
Threatened Wildlife and Plants. We
must publish these 12-month findings
in the Federal Register. This document
represents:
• Our 12-month warranted finding on
a July 16, 2012, petition to reclassify the
Tobusch fishhook cactus from
endangered to threatened (that is, to
‘‘downlist’’ this plant);
• Our determination that the Tobusch
fishhook cactus no longer meets the
definition of endangered under the Act;
and
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• Our proposed rule to reclassify the
Tobusch fishhook cactus from
endangered to threatened on the Federal
List of Endangered and Threatened
Plants.
Previous Federal Actions
We published a final rule to list the
Tobusch fishhook cactus as an
endangered species under the Act on
November 7, 1979 (44 FR 64736). At
that time, we also determined that it
was not prudent to designate critical
habitat for the subspecies because the
publication of critical habitat maps
could make the species more vulnerable
to taking. We issued a recovery plan on
March 18, 1987. The recovery plan has
not been revised. A status review (‘‘5year review’’) under section 4(c)(2)(A) of
the Act was completed for the Tobusch
fishhook cactus on January 5, 2010. The
5-year review recommended that this
plant be reclassified from endangered to
threatened (Service 2010).
On July 16, 2012, we received a
petition dated July 11, 2012, from The
Pacific Legal Foundation, Jim Chilton,
the New Mexico Cattle Growers’
Association, New Mexico Farm &
Livestock Bureau, New Mexico Federal
Lands Council, and Texas Farm Bureau
requesting, among other things, that the
Tobusch fishhook cactus be reclassified
as threatened based on the analysis and
recommendation contained in the 5-year
review. The Service published a 90-day
finding on September 9, 2013 (78 FR
55046) that the petition contained
substantial scientific or commercial
information indicating that the
petitioned action may be warranted. On
November 20, 2015, the Service
received a complaint (New Mexico
Cattle Growers’ Association et al. v.
United States Department of the Interior
et al., No. 1:15–cv–01065–PJK–LF (D.
N.M.)) for declaratory judgment and
injunctive relief from the New Mexico
Cattle Growers’ Association, Jim
Chilton, New Mexico Farm & Livestock
Bureau, New Mexico Federal Lands
Council, and Texas Farm Bureau to,
among other things, compel the Service
to make a 12-month finding on the
petition. This document serves as our
12-month warranted finding on the July
16, 2012, petition to reclassify the
Tobusch fishhook cactus from
endangered to threatened.
Species Status Assessment for Tobusch
fishhook cactus.
We prepared a Species Status
Assessment (SSA) for the Tobusch
fishhook cactus (Service 2016; available
at https://www.regulations.gov), which
includes a thorough review of the
subspecies’ taxonomy, natural history,
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habitats, ecology, populations, and
range. The SSA analyzes individual,
population, and subspecies
requirements, as well as factors affecting
the subspecies’ survival and its current
conditions, to assess the subspecies’
current and future viability in terms of
resilience, redundancy, and
representation.
We define viability as the ability of a
species to persist and to avoid
extinction over the long term. Resilience
refers to the population size and
demographic characteristics necessary
to endure stochastic environmental
variation (Shaffer and Stein 2000, pp.
308–310). Resilient populations are
better able to recover from losses caused
by random variation, such as
fluctuations in recruitment
(demographic stochasticity), variations
in rainfall (environmental stochasticity),
or changes in the frequency of wildfires.
Redundancy refers to the number and
geographic distribution of populations
or sites necessary to endure catastrophic
events (Shaffer and Stein 2000, pp. 308–
310). As defined here, catastrophic
events are rare occurrences, usually of
finite duration, that cause severe
impacts to one or more populations.
Examples of catastrophic events include
tropical storms, unusually high or
prolonged floods, prolonged drought,
and unusually intense wildfire. Species
that have multiple resilient populations
distributed over a larger landscape are
more likely to survive catastrophic
events, since not all populations would
be affected. Representation refers to the
genetic diversity, both within and
among populations, necessary to
conserve long-term adaptive capability
(Shaffer and Stein 2000, pp. 307–308).
Species with greater genetic diversity
are more able to adapt to environmental
changes and to colonize new sites.
The SSA Report provides the
scientific basis that informs our
regulatory determination as to whether
or not this subspecies should be listed
as an endangered or a threatened
species under the Act. This decision
involves the application of standards
within the Act, the Act’s implementing
regulations, and Service policies (see
Finding and Proposed Determination,
below). The following discussion is a
summary of the results and conclusions
from the SSA Report. We are soliciting
peer review of the draft SSA Report
from three objective and independent
scientific experts.
Description
Tobusch fishhook cactus is a rare,
endemic plant of the Edwards Plateau of
central Texas. The common and
scientific names honor Herman
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Tobusch, who first collected it in 1951
(Marshall 1952, p. 78). In the wild, this
globose or columnar cactus rarely
exceeds 5 centimeters (2 inches) in
diameter and in height (Poole and
Janssen 2002, p. 7). As the name
implies, it is armed with curved
‘‘fishhook’’ spines.
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Classification
The taxonomic classifications of
Tobusch fishhook cactus include several
published synonyms. We listed it as a
species, Ancistrocactus tobuschii (44 FR
64736, November 7, 1979), and retained
this classification for the recovery plan
(Service 1987). However, recent
phylogenetic evidence supports
classifying Tobusch fishhook cactus as
subspecies tobuschii of Sclerocactus
brevihamatus (Porter and Prince 2011,
pp. 40–47). It is distinguished
morphologically from its closest
relative, S. brevihamatus ssp.
brevihamatus, on the basis of yellow
versus pink- or brown-tinged flowers,
fewer radial spines, and fewer ribs
(Marshall 1952, p. 79; Poole et al. 2007,
p. 442; Porter and Prince 2011, pp. 42–
45). Additionally, S. brevihamatus ssp.
tobuschii is endemic to limestone
outcrops of the Edwards Plateau, while
S. brevihamatus ssp. brevihamatus
occurs in alluvial soils in the
Tamaulipan Shrublands and
Chihuahuan Desert. A recent
investigation confirmed genetic
divergence between the two subspecies,
although they may interact genetically
in a narrow area where their ranges
overlap (Rayamajhi 2015, pp. 67, 98;
Sharma 2015, p. 1). With the
publication of this proposed rule, we
officially accept the new scientific name
of the Tobusch fishhook cactus as
Sclerocactus brevihamatus ssp.
tobuschii.
Reproduction
Tobusch fishhook cactus grows
slowly, reaching a reproductive size of
about 2 centimeters (0.8 inches) in
diameter after 9 years (Emmett 1995, pp.
168–169). It flowers between late
January and mid-March, and its major
pollinators are honey bees and halictid
bees (Emmett 1995, pp. 74–75;
Lockwood 1995, pp. 428–430; Reemts
and Becraft 2013, pp. 6–7; Langley 2015,
pp. 21–23). The breeding system is
primarily out-crossing, requiring two
individuals for reproduction, but the
subspecies is capable of self-fertilization
(Emmett 1995, p. 70; Langley 2015, pp.
24–28). Reproductive individuals
produce an average of 112 seeds per
year (Emmett 1995, p. 108). Ants may be
seed predators, dispersers, or both
(Emmett 1995, pp. 112–114, 124).
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Mammals or birds may also accomplish
longer distance seed dispersal (Emmett
1995, pp. 115–116, 126). There is little
evidence that seeds persist in the soil
(Emmett 1995, pp. 120–122).
Habitats
When listed as endangered in 1979,
fewer than 200 individuals of Tobusch
fishhook cactus were known from 4
riparian sites, 2 of which had been
destroyed by floods (44 FR 64736,
November 7, 1979; Service 1987, pp. 4–
5). We now understand that those
riparian habitats were atypical; the great
majority of populations that have now
been documented occur in upland sites
dominated by Ashe juniper-live oak
woodlands and savannas on the
Edwards Plateau (Poole and Janssen
2002, p. 2). Soils are classified in the
Tarrant, Ector, Eckrant, and similar
series. Within a matrix of woodland and
savanna, the subspecies occurs in
discontinuous patches of very shallow,
gravelly soils where bare rock and rock
fragments comprise a large proportion of
the surface cover (Sutton et al. 1997, pp.
442–443). Associated vegetation
includes small bunch grasses and forbs.
The subspecies’ distribution within
habitat patches is clumped and tends to
be farther from woody plant cover
(Reemts 2014, pp. 9–10). The presence
of cryptograms, primitive plants that
reproduce by spores rather than seeds,
may be a useful indicator of fine-scale
habitat suitability (Service 2010, p. 17).
Wildfire (including prescribed burning)
causes negligible damage to Tobusch
fishhook cactus populations (Emmett
1995, p. 42; Poole and Birnbaum 2003,
p. 12). The subspecies probably does not
require fire for germination,
establishment, or reproduction, but
periodic burning may be necessary to
prevent the encroachment of woody
plants into its habitats.
Populations and Range
A population of an organism is a
group of individuals within a
geographic area that are capable of
interbreeding or interacting. Although
the term is conceptually simple, it may
be difficult to determine the extent of a
population of rare or cryptic species,
and this is certainly the case for
Tobusch fishhook cactus. Thorough
surveys on public lands, such as state
parks and highway rights-of-way, have
detected groups of individuals, but
since the vast majority of the
surrounding private lands have not been
surveyed, we do not know if these are
small, isolated populations, or parts of
larger interacting populations or metapopulations. For convenience, we often
informally use the terms ‘‘site’’,
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referring to a place where the species
was found, and ‘‘colony’’, referring to a
cluster of individuals, when we do not
know the extent of the local population.
Tobusch fishhook cactus populations
are now confirmed in eight central
Texas counties: Bandera, Edwards, Kerr,
Kimble, Kinney, Real, Uvalde, and Val
Verde. In 2009, the Texas Native
Diversity Database listed 105 element
occurrences, areas in which the species
was present, (EOs; NatureServe 2002, p.
10) of Tobusch fishhook cactus, totaling
3,395 individuals (TXNDD 2009, pp. 1–
210). Texas Parks and Wildlife
Department botanists monitored 118
permanent plots at 12 protected natural
areas from 1991 through 2013 (Poole
and Janssen 2002, entire; Poole and
Birnbaum 2003, entire). Annual
mortality in plots was often greater than
20 percent, and consistently exceeded
recruitment (Emmett 1995, pp. 155–161;
Poole and Birnbaum 2001, p. 5). In
particular, infestations by insect larvae
caused catastrophic population declines
(Emmett 1995, pp. 155–161; Calvert
2003, entire). However, mortality and
recruitment determinations are
confounded by the great difficulty in
detecting live plants in the field (Poole
and Janssen 2002, p. 5; Reemts 2014, pp.
1, 8). Despite the decline of many
individual colonies, the total known
population sizes have steadily
increased, due to the discovery of
previously undetected individuals and
colonies.
Summary of Subspecies Requirements
Requirements of Individuals
Tobusch fishhook cactus plants occur
in patches of very shallow, rocky soil
overlying limestone. The immediate
vicinity of plants is sparsely vegetated
with small bunch grasses and forbs and
there is little or no woody plant cover.
Individuals require an estimated 9 years
to reach a reproductive size of about 2
centimeters (0.8 inches) in diameter.
Reproduction is primarily by outcrossing between unrelated individuals,
and the known pollinators include
honey bees and halictid bees. Outcrossing requires genetically diverse
cactus populations within the foraging
range of pollinators, and is less likely to
occur in small, isolated populations.
Healthy pollinator populations, in turn,
require intact, diverse, native plant
communities. Halictid bees are frequent
natural pollinators of the Tobusch
fishhook cactus. Given their relatively
small size, we expect the foraging range
of these bees to be fairly limited.
Therefore, the health and diversity of
native vegetation within the vicinity of
Tobusch fishhook cactus plants (a range
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of 50 to 500 meters (m) (164 to 1,640
feet (ft)) may be particularly important
for successful cactus reproduction.
Healthy pollinator populations also
require the least possible exposure to
agricultural pesticides within their
foraging ranges.
Requirements of Populations
Population persistence requires stable
or increasing demographic trends.
Although some Tobusch fishhook cactus
individuals live for decades, annual
mortality rates are often greater than 20
percent, and relatively few individuals
live long enough to reproduce. Mortality
within monitored colonies often
exceeds recruitment, and some colonies
have died out. Nevertheless, even where
individual colonies have collapsed, the
total documented population sizes at
many protected natural areas are stable
or increasing, due to discoveries of new
individuals and colonies. Therefore, the
assessment of demographic trends
depends on how populations are
delineated; we conclude that it is more
appropriate to track the collective
populations of multiple colonies that
interact on a landscape scale (i.e., metapopulations). Meta-population
persistence requires recruitment of new
colonies, and/or reestablishment at sites
of former colonies that previously
collapsed. A major cause of mortality is
infestation by insect larvae, mainly by
an undescribed species of Gerstaeckeria
(cactus weevil), and one or more species
of cactus longhorn beetles (Moneilema
spp.). The adults of these parasites are
flightless, so their dispersal to new
colonies is likely to be very limited.
When individual colonies of the cactus
die off, the parasites also die off,
rendering those patches of suitable
habitat available for cactus recolonization. Hence, these periodic
infestations of parasite larvae greatly
influence the population dynamics of
the Tobusch fishhook cactus. The
distance between colonies has two
opposing effects on their persistence.
Greater distance reduces susceptibility
to parasite infestation, but also reduces
the amount of gene flow, by means of
pollinators vectoring pollen, or through
seed dispersal, between colonies. Thus,
the persistence of entire metapopulations would require fairly large
landscapes where discontinuous
patches of suitable habitat are
distributed and populated at a density
just low enough to hold the parasites at
bay, but just high enough for halictid
bees and other pollinators and seed
dispersers to vector genes between
them.
One measure of population resilience
is minimum viable population (MVP),
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which is an estimate of the minimum
population size that has a high
probability of enduring a specified
period of time. Poole and Birnbaum
(2003, p. 1) estimated an MVP of 1,200
individuals for the Tobusch fishhook
cactus, using a surrogate species
approach (Pavlik 1996, pp. 136–137).
For the reasons explained above, MVP
levels are more appropriately applied to
meta-populations rather than individual
colonies of this cactus.
The degree of genetic diversity within
Tobusch fishhook cactus populations is
important for several reasons. First,
diversity within populations should
confer greater resistance to pathogens
and parasites, and greater adaptability to
environmental stochasticity (random
variations, such as annual rainfall and
temperature patterns) and climate
changes. Second, low genetic diversity
within interbreeding populations leads
to a higher incidence of inbreeding, and
potentially to inbreeding depression.
Finally, the breeding system of the
Tobusch fishhook cactus is primarily
out-crossing, so populations with too
little genetic diversity would produce
fewer progeny.
Fire, whether natural or prescribed,
appears to have little effect on
individual Tobusch fishhook cactus
plants. This is because the plants occur
where vegetation is very sparse, and the
plants protrude very little above the
ground and are protected by
surrounding rocks from the heat of
vegetation burning nearby. On the other
hand, periodic fire is likely to be
necessary for population persistence to
reduce juniper encroachment into
suitable habitats. Furthermore, the
diverse shrub and forb vegetation that
sustains healthy pollinator populations
is maintained by periodic wildfire;
without fire, dense juniper groves
frequently displace these shrubs and
forbs. Hence, if the native plant
diversity of entire landscapes
surrounding Tobusch fishhook cactus
populations succumbs to juniper
encroachment, pollinator populations
will likely decline, and reproduction of
the Tobusch fishhook cactus and gene
flow between its colonies may be
reduced.
Subspecies Requirements
In addition to population resilience
(described above under ‘‘Requirements
of Individuals’’ and ‘‘Requirements of
Populations’’), we assess the subspecies’
viability in terms of its redundancy and
representation.
Given that insect parasites are able to
devastate large, dense populations, a
few large populations are much more
vulnerable than many small
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populations. The resilience of the
Tobusch fishhook cactus derives not
merely from the size of metapopulations, but also their density.
Meta-populations with a low density of
colonies may incur loss of genetic
diversity and increased potential for
inbreeding. Conversely, vulnerability to
insect parasitism increases when metapopulations become too dense, or when
individual colonies become too large.
Assessments of resilience (metapopulation size and demographics) and
redundancy (number of metapopulations within representative areas)
depend on how meta-populations are
delineated. We believe that there must
be some optimal range of metapopulation density, i.e. the distance
between meta-populations, and of
colony size, although we do not
currently know what those are.
Representation reflects the genetic
diversity, both within and among
populations, necessary to conserve longterm adaptive capability (Shaffer and
Stein 2000, pp. 307–308). Genetic
diversity within a population can be
measured by the numbers of variant
forms of genes represented in that
population. One measure of this withinpopulation genetic diversity is called
heterozygosity; possible values range
from 0 (all members of a population are
genetically identical for specified genes)
to 1.0 (all members of a population a
genetically different). Another useful
measure is the inbreeding coefficient
(FIS), which ranges from ¥1 (all
members of the population are
heterozygous, containing two forms of
specific genes, and there is no evidence
of inbreeding) to 1.0 (all members are
homozygous, containing only one form
of specific genes, and inbred). Although
there are no heterozygosity levels or
inbreeding coefficients that are
considered healthy for all species, we
may assess the genetic health of the
Tobusch fishhook cactus by comparison
to the observed values of reference
species, such as other cactus species
with similar life histories that are
abundant and widespread (Rayamajhi
2015, pp. 56, 63; Schwabe et al. 2015,
pp. 449, 454–455). The array of different
environments in which a species occurs,
such as the riparian and upland sites
where Tobusch fishhook cactus is
found, can also be used as a proxy
measure for genetic diversity and
therefore representation (Shafer and
Stein 2000, p. 308).
Review of the Recovery Plan
Section 4(f) of the Act directs us to
develop and implement recovery plans
for the conservation and survival of
endangered and threatened species
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unless we determine that such a plan
will not promote the conservation of the
species. Recovery plans identify sitespecific management actions that will
achieve recovery of the species,
measurable criteria that set a trigger for
review of the species’ status, and
methods for monitoring recovery
progress.
Recovery plans are not regulatory
documents; instead they are intended to
establish goals for long-term
conservation of listed species and define
criteria that are designed to indicate
when the threats facing a species have
been removed or reduced to such an
extent that the species may no longer
need the protections of the Act, as well
as actions that may be employed to
achieve reaching the criteria. There are
many paths to accomplishing recovery
of a species, and recovery may be
achieved without all criteria being fully
met or all actions fully implemented.
Recovery of a species is a dynamic
process requiring adaptive management
that may, or may not, fully follow the
guidance provided in a recovery plan.
The Tobusch fishhook cactus recovery
plan was approved by the Service on
March 18, 1987 (Service 1987). Delisting
criteria were not established in the
recovery plan. However, the recovery
plan established a criterion of 3,000
individuals in each of four safe sites for
reclassification from endangered to
threatened.
We now understand that insect
parasites are able to devastate large,
dense populations and we conclude that
a few large populations are much more
vulnerable than many small
populations; therefore, this recovery
criterion should be amended. Currently,
many small populations exist, and
surveyors have documented 3,395
Tobusch fishhook cactus individuals at
105 element occurrences (EOs) in 8
counties of the Edwards Plateau,
including 12 sites managed either by the
state or conservation organizations,
where monitored populations ranged
from 34 to 1,090 individuals.
Summary of Factors Affecting the
Subspecies
Section 4 of the Act and its
implementing regulations (50 CFR part
424) set forth the procedures for listing
species, reclassifying species, or
removing species from listed status. A
species may be determined to be an
endangered or threatened species due to
one or more of the five listing factors
described in section 4(a)(1) of the Act:
(A) The present or threatened
destruction, modification, or
curtailment of its habitat or range; (B)
overutilization for commercial,
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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. A species may be reclassified
or delisted on the same basis.
Consideration of these factors was
incorporated into the Tobusch fishhook
cactus SSA (Service 2016; available at
https://www.regulations.gov under
Docket No. FWS–R2–ES–2016–0130)
and projected in future scenarios to
evaluate viability of the Tobusch
fishhook cactus. The effects of
conservation measures were also
assessed as part of the current condition
of the Tobusch fishhook cactus in the
SSA Report, and those effects were
projected in future scenarios.
Land Use Changes (Factor A)
Relatively little urban and industrial
development is occurring within the
semi-arid, sparsely populated eightcounty known range of the Tobusch
fishhook cactus. However, a significant
ongoing trend throughout the
subspecies’ range is the subdivision of
large ranches leading to a proliferation
of roads, fences, power lines, and
residential development, all of which
contribute incrementally to habitat loss
and fragmentation.
The predominant, historic land use
throughout the Edwards Plateau has
been livestock grazing. In many cases,
poor rangeland management during the
last century has caused the depletion of
herbaceous vegetation, cessation of the
natural wildfire cycle, proliferation of
dense juniper stands, soil erosion, and
reduced infiltration and storage of
rainwater in the soil profile; all of these
changes are likely to have harmed
Tobusch fishhook cactus populations.
The change to a primarily recreational
land use often entails continued grazing,
but at a sustainable stocking density.
Prescribed burning may be one of the
most important vegetation management
tools for sustaining Tobusch fishhook
cactus populations because it reduces
woody vegetation encroachment.
However, the proliferation of residential
development within the species’ habitat
makes this tool more challenging for
natural resource managers to use.
Changes in Vegetation and Wildfire
Frequency (Factor A)
Bray (1904, pp. 14–15, 23–24)
documented the rapid transition of
grasslands to woodlands in the Edwards
Plateau occurring more than a century
ago; he attributed this change to
overgrazing, the depletion of grasses,
and the cessation of wildfires. Fonteyn
et al. (1988, p. 79) state that savannas
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covered portions of the pre-settlement
Edwards Plateau, and since 1850 were
transformed to shrubland or woodland
‘‘primarily by suppression of recurring
natural and anthropogenic fires and the
introduction of livestock.’’ They list the
fire-sensitive Ashe juniper (Juniperus
ashei) as the most successful of many
woody plants that have invaded
grasslands. Reemts (2014 p. 1) lists the
encroachment of woody plants into the
rocky, open habitat as one of several
remaining habitat-related threats that
endanger the Tobusch fishhook cactus.
Livestock Grazing (Factor A)
The recovery plan stated,
‘‘Ancistrocactus tobuschii plants have
been observed that were either uprooted
or had apical meristem injuries from
livestock trampling.’’ Nevertheless,
livestock trampling and herbivory have
not subsequently been identified as
significant causes of mortality or
damage to Tobusch fishhook cactus
plants. Their recurved spines and small
size probably protect Tobusch fishhook
cactus plants from livestock herbivory.
Livestock are not attracted to the
sparsely vegetated outcrops where
Tobusch fishhook cactus plants
typically occur, and the plants are often
nestled among larger rocks. While
livestock trampling probably occurs in
grazed habitats, we have no evidence
that it represents a significant threat to
the subspecies. A number of healthy
Tobusch fishhook cactus populations
occur on well-managed rangeland. We
conclude that properly managed
livestock grazing, especially where
juniper thinning and prescribed burning
are used to manage rangeland, is
generally compatible with conservation
of this cactus.
Illegal Collection (Factor B)
Many rare cactus populations have
been depleted by overzealous collectors.
The recovery plan lists illegal collection
as a threat to the subspecies. Westlund
(1991, pp. 2, 35, 39) found six
specimens of Tobusch fishhook cactus,
grown legally from seed, for sale in
commercial nurseries. Poole and
Janssen (2002, p. 9) noted that one
population of the Tobusch fishhook
cactus was heavily depleted by
collection, but concluded that
‘‘collection is not currently perceived to
be a grave threat.’’ Although illegal
collection has not significantly
impacted the subspecies, the wild
populations openly accessed by the
public remain vulnerable. The potential
threat of illegal collection might be
diminished if seeds and plants of legally
propagated Tobusch fishhook cacti
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become easier and less expensive to
obtain than wild-dug specimens.
Parasites (Factor C)
The Tobusch fishhook cactus weevil
(Gerstaeckeria spp.) and cactus
longhorn beetle (Moneilema spp.)
parasitize and kill Tobusch fishhook
cactus plants and have contributed
significantly to drastic declines in many
of the known populations (Calvert 2003,
entire).
Periodic outbreaks of insect
parasitism appear to be an unavoidable
natural cycle. For this reason, large
cactus populations could eventually
host very large parasite populations,
leading to their collapse. The most
appropriate conservation strategy may
be to protect larger numbers of small,
widely spaced meta-populations, rather
than fewer large populations that are
more vulnerable to parasites.
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Other Herbivory (Factor C)
Poole and Birnbaum (2003, pp. 11–12)
report that jackrabbits browse the
cactus, but in most sites cause less than
2 percent mortality. If the root systems
are not too badly damaged, they may
regenerate one or more new stems. Feral
hogs have uprooted plants in many sites
(also observed by Reemts (2015, p. 1)).
An unidentified ant species has also
caused 1 percent mortality at some sites
by creating mounds on top of the stems.
With the exception of feral hogs,
herbivory does not appear to be a
significant cause of mortality or damage
to Tobusch fishhook cactus plants.
Inadequacy of Existing Regulatory
Mechanisms (Factor D)
Federally listed plants occurring on
private lands have limited protection
under the Act, unless also protected by
state laws; the State of Texas also
provides very little protection to listed
plant species on private lands.
Approximately 95 percent of Texas land
area is privately owned. It is reasonable
to assume that the vast majority of
existing Tobusch fishhook cactus
habitat, including sites that have not
been documented, occurs on private
land. Therefore, most of the subspecies’
populations and habitats are not subject
to Federal or state protection unless
there is a Federal nexus, such as
provisions of the Clean Water Act (33
U.S.C. 1251 et seq.) or a federally
funded project.
Demographic Consequences of Small
Population Size and Density (Factor E)
Poole and Birnbaum (2003, p. 1)
estimated an MVP of 1,200 individuals
(Service 2016, section II.7.5, available at
https://www.regulations.gov under
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Docket No. FWS–R2–ES–2016–0130).
For Tobusch fishhook cactus, MVP
levels are more appropriately applied to
meta-populations rather than individual
colonies. Small populations are less able
to recover from losses caused by random
environmental changes (Shaffer and
Stein 2000, pp. 308–310), such as
fluctuations in recruitment
(demographic stochasticity), variations
in rainfall (environmental stochasticity),
or changes in the frequency of wildfires.
The Tobusch fishhook cactus has a
predominantly out-crossing breeding
system. The probability of successful
fertilization between unrelated
individuals is reduced in small, isolated
populations. The remaining plants
would produce fewer viable seeds,
further reducing population recruitment
and engendering a downward spiral
toward extirpation. The demographic
consequences of small population size
are compounded by genetic
consequences (discussed below),
because reduced out-crossing
corresponds to increased inbreeding. In
addition to population size, it is likely
that population density within metapopulations also influences population
viability; density must be high enough
for gene flow within meta-populations,
but low enough to minimize parasite
infestations.
Genetic Consequences of Small
Population Sizes (Factor E)
Small, reproductively isolated
populations are susceptible to the loss
of genetic diversity, to genetic drift, and
to inbreeding. The loss of genetic
diversity may reduce the ability of a
species or population to resist
pathogens and parasites, to adapt to
changing environmental conditions, or
to colonize new habitats. Conversely,
populations that pass through a ‘‘genetic
bottleneck’’, i.e. a time of significant loss
of genetic diversity, may subsequently
benefit through the elimination of
harmful alleles, or the variant forms of
a given gene. Nevertheless, the net
result of loss of the genetic diversity is
likely to be a loss of fitness and lower
chance of survival of populations and of
the subspecies.
Genetic drift is a change in the
frequencies of alleles in a population
over time. Genetic drift can arise from
random differences in founder
populations, i.e. new populations
originally established by a very small
number of individuals, and the random
loss of rare alleles in small, isolated
populations. Genetic drift may have a
neutral effect on fitness, or contribution
to the gene pool, in larger populations,
but may cause the loss of genetic
diversity in small populations. Genetic
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drift may also result in the adaptation of
an isolated population to the climates
and soils of specific sites, leading to the
development of distinct genotypes that
are specifically adapted to a particular
ecological area and to speciation, or the
evolution of new species. For example,
the genetic divergence of Sclerocactus
brevihamatus ssp. brevihamatus and S.
brevihamatus ssp. tobuschii (Rayamajhi
2015, pp. 67, 98; Service 2016, pp. 6–
7, available at https://
www.regulations.gov under Docket No.
FWS–R2–ES–2016–0130) may have
resulted when populations of the
species brevihamatus migrated into
separate geographic regions, and once
separated, each population adapted to
different soils, climate, and pollinator
species.
Inbreeding depression is the loss of
fitness among offspring of closely
related individuals. While most animal
species are susceptible to inbreeding
depression, plant species vary greatly in
response to inbreeding. Levels of
inbreeding can be measured with the
inbreeding coefficient (FIS), which
ranges from ¥1 (all members of the
population are heterozygous for specific
genes and there is no evidence of
inbreeding) to 1.0 (all members are
homozygous and inbred). Rayamajhi
(2015, pp. 63–64) found relatively high
inbreeding coefficients in three of eight
populations, which he attributed to
mating of close relatives within small,
isolated populations. Nevertheless, we
do not know to what extent inbreeding
has reduced fitness of these
populations.
Land Ownership (Factor E)
A large portion of the known
individuals and populations of the
Tobusch fishhook cactus occurs on
privately owned land. This does not
constitute a direct threat to the
subspecies, and many landowners have
demonstrated interest and enthusiasm
for its conservation. However, private
ownership makes conservation more
challenging for several reasons. Access
to populations and habitats is subject to
the interests of hundreds of individual
landowners. Consequently, our
knowledge of the subspecies’ actual
status is far from complete. Establishing
and maintaining cooperative
relationships with large numbers of
private landowners is time-consuming,
and these important relationships may
lapse when personnel of conservation
organizations retire or pursue other
career choices. The ownership of private
lands changes hands over time, and
future owners may choose not to
continue conservation efforts that were
supported by previous owners. Hence, it
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is difficult to assure permanent
conservation on private lands. These
challenges underscore the importance of
effective landowner outreach in the
conservation of the Tobusch fishhook
cactus.
Climate Change (Factor E)
The Fifth Assessment Report of the
Intergovernmental Panel on Climate
Change (IPCC) (IPCC 2013, p. 23)
projects the following changes by the
end of the 21st century, relative to the
1986 to 2005 averages: It is virtually
certain that most land areas will
experience warmer and/or fewer cold
days and nights; it is virtually certain
that most land areas will experience
warmer and/or more frequent hot days
and nights; it is very likely that the
frequency and/or duration of warm
spells and heat waves will increase in
most land areas; it is very likely that the
frequency, intensity, and/or amount of
heavy precipitation will increase in
mid-latitude land masses; it is likely
that the intensity and/or duration of
droughts will increase on a regional to
global scale. The magnitude of projected
changes varies widely, depending on
which scenario of future greenhouse gas
emissions is used.
To evaluate how the climate of
Tobusch fishhook cactus habitats may
change, we used the National Climate
Change Viewer (U.S. Geological Survey
2015) to compare past and projected
future climate conditions for Edwards
County, Texas. The baseline for
comparison was the observed mean
values from 1950 through 2005, and 30
climate models were used to project
future conditions for 2050 through 2074.
We selected the climate parameters of
August maximum temperature, January
minimum temperature, annual mean
precipitation, and annual mean
evaporative deficit. These particular
parameters were selected from those
available because they represented those
most likely to impact the survival of
individuals. The highest temperature of
the year (August maximum temperature)
could potentially affect individuals by
exacerbating the effects of drought and
the lowest temperatures of the year
(January minimum temperature) could
expose individuals to freezing
temperatures. The annual mean
precipitation and evaporative deficit
provide measures of drought that could
negatively affect individuals. The
results are described in detail in the
SSA Report (Service 2016, available at
https://www.regulations.gov under
Docket No. FWS–R2–ES–2016–0130),
but generally, these models project that
plant growth and survival in Edwards
County will become more moisture-
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limited, although the degree of change
varies under different scenarios.
Nevertheless, we do not know how
the Tobusch fishhook cactus responded
to prior climate changes, nor can we
determine how these projected climate
changes will affect the Tobusch
fishhook cactus and its habitat. Warmer
winters could extend the growing
season and improve reproduction and
survival of the Tobusch fishhook cactus,
but might also increase survival of
parasite larvae. Heavier, less frequent
rainfall could reduce establishment of
Tobusch fishhook cactus seedlings, but
perhaps less so than the bunch grasses
with which it competes. Zaya et al.
(2014, pp. 37–38) projected that climate
changes will be detrimental to 4
populations, due primarily to lower
survival and reproduction, and
beneficial to 6 others, given increased
individual growth rates. Thus, although
it is likely that the projected climate
changes will affect the survival of the
Tobusch fishhook cactus in infinitely
complex ways, we do not currently
know what the net result of beneficial
and detrimental effects will be.
Conservation Efforts
Support for the recovery of Tobusch
fishhook cactus has come from a variety
of sources. Conservation measures from
nine formal consultations under section
7 of the Act supported scientific
investigations, the salvage of
individuals that would have been
destroyed by development, and
contributions to the Tobusch Fishhook
Cactus Conservation Fund (Fund). The
Lady Bird Johnson Wildflower Center
manages the Fund through a
memorandum of agreement with the
Service. The Fund supported three
projects that contributed significantly to
our knowledge of the Tobusch fishhook
cactus. These three Tobusch fishhook
cactus projects included a study on the
effects of shading by woody shrubs, a
conservation genetics study, and
population viability analyses. Five
grants under section 6 of the Act have
supported scientific investigations and
extensive inventory and monitoring of
the subspecies on state highway rightsof-way, in state parks, in wildlife
management areas, and in state natural
areas. Four graduate-level investigations
focused on the Tobusch fishhook cactus,
leading to three Master’s theses and a
doctoral dissertation, and provided
information that is essential to the
subspecies’ conservation and recovery.
Current Status
By 2009, surveyors documented 3,395
Tobusch fishhook cactus individuals at
105 E.O.s in 8 counties of the Edwards
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Plateau. This includes 12 sites managed
either by the state or conservation
organizations where monitored
populations ranged from 34 to 1,090
individuals, and totaled 3,139
individuals. Recent surveys found 660
new Tobusch fishhook cactus
individuals that probably represent
many new E.O.s, bringing the total
documented number of individuals
(based on the most recent surveys) to
over 4,000.
We developed a model of potential
habitat based on the soil types and
watersheds of documented populations.
This model predicts that over 2 million
hectares (ha) (5 million acres (ac)) of
potential habitat occurs in the eight
counties of the cactus’ currently known
range, as well as in some adjacent
counties (mainly Crockett and Sutton
Counties). However, we have no records
of the Tobusch fishhook cactus
occurring in any of these adjacent
counties, nor have any surveys for the
subspecies been conducted there, to our
knowledge. Within these areas of
potential habitat, only a small fraction
of the total area contains suitable
habitat, consisting of discontinuous,
open areas on or near exposed limestone
strata. Based on 25 surveys widely
distributed across the subspecies range,
we calculated an average density across
the range of the species. That average
density was applied to the amount of
suitable habitat and used to calculate an
estimate of the global population. We
estimate that the global population is
about 480,000 individuals (Service
2016, Appendix B, available at https://
www.regulations.gov under Docket No.
FWS–R2–ES–2016–0130).
From 1991 through 2013, many
individual colonies of the Tobusch
fishhook cactus declined and some have
died out completely. A principle cause
of colony decline is parasitism by the
larvae of flightless insects, including an
undescribed species of Gerstaeckeria (a
cactus weevil) and one or more species
of Moneilema (cactus longhorn beetles).
At the same time, total populations in
monitored sites (consisting of multiple
colonies; meta-populations) have
remained steady or have increased, due
to the discovery of new colonies or recolonization of formerly depleted
colonies. We believe that the Tobusch
fishhook cactus co-evolved with these
parasitic organisms, and that they are
important drivers of its population
dynamics. Large, dense cactus
populations become susceptible to
larval parasitism and decline until
parasite populations cannot be
sustained. Meta-populations, consisting
of multiple, widely-dispersed colonies,
appear to be stable; however, we do not
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know what the long-term demographic
trends are at the meta-population or
subspecies level.
The expected heterozygosity (He) and
observed heterozygosity (Ho) are useful
measures of within-population genetic
diversity; possible values range from 0
(all members of a population are
genetically identical for specified genes)
to 1.0 (all members of a population are
genetically different). Rayamajhi (2015,
pp. 57–61, 64, 97) determined that the
mean He for nine populations of
Sclerocactus brevihamatus ssp.
tobuschii was 0.59, and the mean Ho
was 0.37. Through comparison to
columnar cactus species that are
endemic or have limited geographic
distribution, he concluded that, for S.
brevihamatus ssp. tobuschii, He was
moderately high, and Ho was moderate
which suggest there is sufficient genetic
diversity to conserve long-term adaptive
capability.
Another useful measure is the
inbreeding coefficient (FIS), which
ranges from ¥1 (all members of the
population are heterozygous for specific
genes and there is no evidence of
inbreeding) to 1.0 (all members are
homozygous and inbred). For
Sclerocactus brevihamatus ssp.
tobuschii, the mean FIS was 0.38 (range
of 0.15 to 0.63) (Rayamajhi 2015). While
most populations had an apparently
healthy degree of out-crossing, three
populations of S. brevihamatus ssp.
tobuschii were at relatively higher risk
of inbreeding effects and may have
suffered recent genetic bottlenecks
through population declines. The higher
level of inbreeding in these populations
may be due to small, isolated
populations; mating of close relatives
within populations; the limited range of
seed dispersal; and the limited range
and foraging behavior of a primary
pollinator, halictid bees.
There were relatively few genetic
differences between the nine Tobusch
fishhook cactus populations in
Rayamajhi’s study (2015), regardless of
the distance between populations. This
evidence supports a hypothesis that
gene flow has occurred throughout the
subspecies’ range, at least until recently;
however, recently isolated populations
may not yet show genetic
differentiation, in part because
individuals can live and contribute to
the local gene pool at least for several
decades.
Assessment of Current and Future
Viability
We estimate that about 480,000
individuals of Tobusch fishhook cactus
are distributed at low density over an
area of more than 2 million ha (5
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million ac). Thus, it is likely that the
Tobusch fishhook cactus has multiple,
resilient populations. Although many
individual colonies have declined,
meta-population levels of monitored
areas appear stable; however, we have
very little data on meta-population
trends over the subspecies’ entire range.
Genetic data from wild populations
indicate that most populations, and the
subspecies as a whole, currently possess
sufficient genetic diversity to conserve
long-term adaptive capability.
Nevertheless, some small, isolated
populations have higher levels of
inbreeding, and may as a consequence
suffer reduced fitness and reproduction.
There is relatively little genetic diversity
between populations, which is evidence
that gene flow has occurred fairly
recently between populations.
Considering the naturally low densities
of Tobusch fishhook cactus populations,
gene flow among them may be easily
disrupted.
Demographic population viability
analyses (PVA) of monitoring plot data
predicted stable or increasing trends for
two or three populations, moderate
declines for two populations, and large
to precipitous declines in five
populations over the next 50 years (Zaya
et al. 2014, pp. 29–42). When expected
climate changes were included in these
analyses, four populations responded
negatively to climate changes, and six
populations responded positively
(compared to PVA without climate
changes). These findings predict an
overall decline in subspecies viability
over the 50 year time frame. However,
we do not know how well these
analyses project the demographic trends
of meta-populations distributed over
larger landscapes.
We project what the viability of the
Tobusch fishhook cactus could be,
between 2050 and 2074, under three
scenarios. We considered how
conservation support, the subspecies’
geographic range, habitat management,
population management, and climate
changes may contribute to these
scenarios. The first scenario represents
improvements over current conditions.
The second scenario represents the most
likely conditions if current trends
continue. The third scenario represents
deteriorating conditions. We conclude
that under the most likely scenario, the
subspecies remains viable but requires
continued conservation, management,
and protection.
Finding and Proposed Determination
We have carefully assessed the best
scientific and commercial information
available regarding the past, present,
and future threats to the Tobusch
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fishhook cactus. The Tobusch fishhook
cactus was listed as endangered in 1979,
due to: Few known populations, habitat
destruction, and altered stream flows
(Factor A); illegal collection (Factor B);
and very limited geographic range,
small population sizes, restricted gene
pool, and lack of reproduction (Factor
E). We now know there are many more
populations over a much wider area;
about 4,000 individuals have been
documented at more than 105 EOs.
These data allow us to estimate that the
total population size is about 480,000
individuals distributed at low density
over about 2 million ha (5 million ac).
Most habitats are relatively secure,
given that they are in remote, rocky
areas that are unsuitable for growing
crops. However, the great majority is on
private lands that are becoming
increasingly fragmented and may be
subject to destruction or modification.
Many of the known populations are
small and isolated, and the monitored
portions of numerous populations have
declined. Demographic population
viability analyses predict an overall
future decline in subspecies’ viability.
However, we do not know how well
these analyses project the demographic
trends of meta-populations distributed
over larger landscapes. We know that
insect parasites are a major cause of
mortality, and may naturally reduce
populations to low densities. Many
populations have sufficient genetic
diversity to confer long-term adaptive
capability, but some small, isolated
populations have higher levels of
inbreeding and may be affected by
reduced fitness and reproduction. It is
likely that projected climate changes
will affect the Tobusch fishhook cactus,
but we do not currently know whether
this will have a net positive or negative
effect on its viability.
We have determined that the Tobusch
fishhook cactus’ current viability is
higher than was known at the time of
listing. Based on the analysis in the
SSA, and summarized above, we believe
that the Tobusch fishhook cactus does
not meet the definition of endangered
under the Act. However, due to
continued threats from the demographic
and genetic consequences of small
population sizes and geographic
isolation, insect parasitism, feral hog
depredation, and changes in the wildfire
cycle and vegetation, as well as
unknown long-term effects of land use
changes and climate changes, we find
that the Tobusch fishhook cactus is
likely to become an endangered species
within the foreseeable future throughout
all of its range. Because we have found
that the Tobusch fishhook cactus
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(Sclerocactus brevihamatus ssp.
tobuschii; currently listed as
Ancistrocactus tobuschii) meets the
definition of threatened under the Act,
we propose to reclassify it from
endangered to threatened on the Federal
List of Endangered and Threatened
Plants (List).
Significant Portion of the Range
Analysis
asabaliauskas on DSK3SPTVN1PROD with PROPOSALS
Under the Act and our implementing
regulations, a species may warrant
listing if it is in danger of extinction or
likely to become so throughout all or a
significant portion of its range. We
published a final policy interpreting the
phrase ‘‘significant portion of its range’’
(SPR) (79 FR 37578; July 1, 2014). The
final policy states that: (1) If a species
is found to be endangered or threatened
throughout a significant portion of its
range, the entire species is listed as
endangered or threatened, respectively,
and the Act’s protections apply to all
individuals of the species wherever
found; (2) a portion of the range of a
species is ‘‘significant’’ if the species is
not currently endangered or threatened
throughout all of its range, but the
portion’s contribution to the viability of
the species is so important that, without
the members in that portion, the species
would be in danger of extinction, or
likely to become so in the foreseeable
future, throughout all of its range; (3)
the range of a species is considered to
be the general geographical area within
which that species can be found at the
time the Service makes any particular
status determination; and (4) if a
vertebrate species is endangered or
threatened throughout a significant
portion of its range, and the population
in that significant portion is a valid
distinct population segment (DPS), we
will list the DPS rather than the entire
taxonomic species or subspecies.
Because we have determined that the
Tobusch fishhook cactus is threatened
throughout all of its range, no portion of
its range can be ‘‘significant’’ for the
purposes of the definitions of
‘‘endangered species’’ and ‘‘threatened
species.’’
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Conclusion
Using the best available scientific
information, we have determined that
the Tobusch fishhook cactus is not
currently in danger of extinction
throughout all or a significant portion of
its range, but is likely to become
endangered within the foreseeable
future throughout all of its range. In
accordance with 50 CFR 424.11(c), we
therefore propose to reclassify the
Tobusch fishhook cactus as threatened
on the Federal List of Endangered and
Threatened Plants at 50 CFR 17.12(h).
Effects of the Rule
This proposal, if made final, would
revise 50 CFR 17.12(h) to reclassify the
Tobusch fishhook cactus as threatened
on the Federal List of Endangered and
Threatened Plants. There is no critical
habitat designated for this subspecies;
therefore, this proposed rule would not
affect 50 CFR 17.96.
Required Determinations
environmental impact statements, as
defined under the authority of the
National Environmental Policy Act of
1969 (42 U.S.C. 4321 et seq.), need not
be prepared in connection with
regulations pursuant to section 4(a) of
the Act. We published a notice outlining
our reasons for this determination in the
Federal Register on October 25, 1983
(48 FR 49244).
References Cited
A complete list of all references cited
in this proposed rule is available at
https://www.regulations.gov at Docket
No. FWS–R2–ES–2016–0130, or upon
request from the Austin Ecological
Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this proposed
rule are staff members of the Service’s
Austin Ecological Services Field Office
(see FOR FURTHER INFORMATION CONTACT).
List of Subjects in 50 CFR Part 17
Clarity of the Rule
We are required by Executive Orders
12866 and 12988 and by the
Presidential Memorandum of June 1,
1998, to write all rules in plain
language. This means that each rule we
publish must:
(1) Be logically organized;
(2) Use the active voice to address
readers directly;
(3) Use clear language rather than
jargon;
(4) Be divided into short sections and
sentences; and
(5) Use lists and tables wherever
possible.
If you feel that we have not met these
requirements, send us comments by one
of the methods listed in ADDRESSES. To
better help us revise the rule, your
comments should be as specific as
possible. For example, you should tell
us the numbers of the sections or
paragraphs that are unclearly written,
which sections or sentences are too
long, the sections where you feel lists or
tables would be useful, etc.
Endangered and threatened species,
Exports, Imports, Reporting and
recordkeeping requirements,
Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend
part 17, subchapter B of chapter I, title
50 of the Code of Federal Regulations,
as set forth below:
PART 17—ENDANGERED AND
THREATENED WILDLIFE AND PLANTS
1. The authority citation for part 17
continues to read as follows:
■
Authority: 16 U.S.C. 1361–1407; 1531–
1544; and 4201–4245, unless otherwise
noted.
2. Amend § 17.12(h), the List of
Endangered and Threatened Plants,
under FLOWERING PLANTS by:
■ a. Removing the entry for
‘‘Ancistrocactus tobuschii’’; and
■ b. Adding, in alphabetical order, an
entry for ‘‘Sclerocactus brevihamatus
ssp. tobuschii’’ to read as follows:
■
National Environmental Policy Act
§ 17.12
We have determined that
environmental assessments and
*
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Fmt 4702
Sfmt 4702
Endangered and threatened plants.
*
*
(h) * * *
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*
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Scientific
name
Common name
Where listed
Listing citations and applicable
rules
Status
FLOWERING
PLANTS
*
Sclerocactus
brevihamatus ssp.
tobuschii
*
*
*
*
Tobusch fishhook cactus ................ Wherever found ................................
*
*
*
Dated: December 15, 2016.
Stephen Guertin,
Acting Director, U.S. Fish and Wildlife
Service.
[FR Doc. 2016–31296 Filed 12–28–16; 8:45 am]
BILLING CODE 4333–15–P
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
50 CFR Part 622
[Docket No. 160426363–6363–01]
RIN 0648–BG03
Fisheries of the Caribbean, Gulf of
Mexico, and South Atlantic; Coastal
Migratory Pelagic Resources in the
Gulf of Mexico and Atlantic Region;
Amendment 26
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Proposed rule; request for
comments.
AGENCY:
NMFS proposes to implement
management measures described in
Amendment 26 to the Fishery
Management Plan for the Coastal
Migratory Pelagics Fishery of the Gulf of
Mexico and Atlantic Region (FMP) as
prepared and submitted jointly by the
Gulf of Mexico Fishery Management
Council (Gulf Council) and South
Atlantic Fishery Management Council
(South Atlantic Council). Amendment
26 and this proposed rule would adjust
the management boundary for the Gulf
of Mexico (Gulf) and Atlantic migratory
groups of king mackerel; revise
acceptable biological catch (ABC),
commercial and recreational annual
catch limits (ACLs), commercial quotas
and recreational annual catch targets
(ACTs) for Atlantic migratory group
king mackerel; allow limited retention
and sale of Atlantic migratory group
king mackerel incidentally caught in the
shark gillnet fishery; establish a
asabaliauskas on DSK3SPTVN1PROD with PROPOSALS
SUMMARY:
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*
Frm 00031
Fmt 4702
*
*
44 FR 64736; 11/7/1979, [Federal
Register citation of the final
rule].
*
commercial split season for Atlantic
migratory group king mackerel in the
Atlantic southern zone; establish a
commercial trip limit system for
Atlantic migratory group king mackerel
in the Atlantic southern zone; revise the
commercial and recreational ACLs for
Gulf migratory group king mackerel;
revise commercial zone quotas for Gulf
migratory group king mackerel; and
modify the recreational bag limit for
Gulf migratory group king mackerel.
The purpose of Amendment 26 and this
proposed rule is to ensure that king
mackerel management is based on the
best scientific information available,
while increasing the social and
economic benefits of the fishery.
DATES: Written comments must be
received on or before January 30, 2017.
ADDRESSES: You may submit comments
on the proposed rule, identified by
‘‘NOAA–NMFS–2016–0120,’’ by either
of the following methods:
• Electronic submission: Submit all
electronic public comments via the
Federal e-Rulemaking Portal: https://
www.regulations.gov. Go to
www.regulations.gov/
#!docketDetail;D=NOAA-NMFS-20160120, click the ‘‘Comment Now!’’ icon,
complete the required fields, and enter
or attach your comments.
• Mail: Submit written comments to
Karla Gore, Southeast Regional Office,
NMFS, 263 13th Avenue South, St.
Petersburg, FL 33701.
Instructions: Comments sent by any
other method, to any other address or
individual, or received after the end of
the comment period, may not be
considered by NMFS. All comments
received are a part of the public record
and will generally be posted for public
viewing on www.regulations.gov
without change. All personal identifying
information (e.g., name, address, etc.),
confidential business information, or
otherwise sensitive information
submitted voluntarily by the sender will
be publicly accessible. NMFS will
accept anonymous comments (enter ‘‘N/
A’’ in required fields if you wish to
remain anonymous).
PO 00000
T
Sfmt 4702
*
*
Electronic copies of Amendment 26
may be obtained from the Southeast
Regional Office Web site at https://
sero.nmfs.noaa.gov/sustainable_
fisheries/gulf_sa/cmp/2016/am%2026/
index.html. Amendment 26 includes an
environmental assessment, a Regulatory
Flexibility Act (RFA) analysis, and a
regulatory impact review.
FOR FURTHER INFORMATION CONTACT:
Karla Gore, Southeast Regional Office,
NMFS, telephone: 727–551–5753, or
email: karla.gore@noaa.gov.
SUPPLEMENTARY INFORMATION: The
coastal migratory pelagic fishery of the
Gulf and Atlantic Regions is managed
under the FMP and includes the
management of the Gulf and Atlantic
migratory groups of king mackerel,
Spanish mackerel and cobia. The FMP
was prepared jointly by the Gulf and
South Atlantic Councils (Councils) and
is implemented through regulations at
50 CFR part 622 under authority of the
Magnuson-Stevens Fishery
Conservation and Management Act
(Magnuson-Stevens Act).
Background
The Magnuson-Stevens Act requires
NMFS and regional fishery management
councils to prevent overfishing and
achieve, on a continuing basis, OY from
federally managed fish stocks.
In September of 2014, the Southeast
Data, Assessment, and Review (SEDAR)
38 stock assessment was completed for
both the Gulf and Atlantic migratory
groups of king mackerel (SEDAR 38).
SEDAR 38 determined that both the
Gulf and Atlantic migratory groups of
king mackerel are not overfished and are
not undergoing overfishing. The Gulf
Council’s and South Atlantic Council’s
respective Scientific and Statistical
Committees (SSCs) reviewed the
assessment and concluded that SEDAR
38 should form the basis for revisions to
the overfishing limit (OFL), acceptable
biological catch (ABC), and ACLs for the
two migratory groups of king mackerel.
SEDAR 38 also provided genetic
information on king mackerel, which
indicated that the Councils’
E:\FR\FM\29DEP1.SGM
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Agencies
[Federal Register Volume 81, Number 250 (Thursday, December 29, 2016)]
[Proposed Rules]
[Pages 95932-95941]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-31296]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2016-0130; FXES11130900000 178 FF09E42000]
RIN 1018-BB90
Endangered and Threatened Wildlife and Plants; Reclassifying the
Tobusch Fishhook Cactus From Endangered to Threatened on the Federal
List of Endangered and Threatened Plants
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule and 12-month petition finding; request for
comments.
-----------------------------------------------------------------------
SUMMARY: Under the authority of the Endangered Species Act of 1973, as
amended (Act), we, the U.S. Fish and Wildlife Service (Service),
propose to reclassify the Tobusch fishhook cactus (Sclerocactus
brevihamatus ssp. tobuschii; currently listed as Ancistrocactus
tobuschii) from endangered to threatened on the Federal List of
Endangered and Threatened Plants (List). This determination is based on
a thorough review of the best available scientific and commercial
information, which indicates that the threats to this plant have been
reduced to the point that it no longer meets the definition of
endangered under the Act, but may still become endangered within the
foreseeable future. This document also serves as the 12-month finding
on a petition to reclassify this plant from endangered to threatened.
DATES: We will accept comments received or postmarked on or before
February 27, 2017. Please note that if you are using the Federal
eRulemaking Portal (see ADDRESSES), the deadline for submitting an
electronic comment is 11:59 p.m. Eastern Time on this date. We must
receive requests for public hearings, in writing, at the address shown
in FOR FURTHER INFORMATION CONTACT by February 13, 2017.
ADDRESSES: Written comments: You may submit comments by one of the
following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Search box, enter FWS-R2-ES-2016-0130,
which is the docket number for this rulemaking. Then, click on the
Search button. On the resulting page, in the Search panel on the left
side of the screen, under the Document Type heading, click on the
Proposed Rules link to locate this document. You may submit a comment
by clicking on ``Comment Now!''
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R2-ES-2016-0130, U.S. Fish and Wildlife
Service, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described
above. We will post all comments on https://www.regulations.gov. This
generally means that we will post any personal information you provide
us (see Public Comments, below, for more information).
Copies of Documents: This proposed rule and supporting documents
are available on https://www.regulations.gov. In addition, the
supporting file for this proposed rule will be available for public
inspection, by appointment, during normal business hours, at the Austin
Ecological Services Field Office, 10711 Burnet Rd., Suite 200, Austin,
TX 78727; telephone 512-490-0057.
FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor, U.S.
Fish and Wildlife Service, Austin Ecological Services Field Office,
10711 Burnet Rd., Suite 200, Austin, TX 78727; telephone 512-490-0057;
or facsimile 512-490-0974. Persons who use a telecommunications device
for the deaf (TDD) may call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Information Requested
Public Comments
We want any final rule resulting from this proposal to be as
effective as possible. Therefore, we invite tribal and governmental
agencies, the scientific community, industry, and other interested
parties to submit comments or recommendations concerning any aspect of
this proposed rule. Comments should be as specific as possible.
To issue a final rule to implement this proposed action, we will
take into consideration all comments and any additional information we
receive. Such communications may lead to a final rule that differs from
this proposal. All comments, including commenters' names and addresses,
if provided to us, will become part of the supporting record.
We are specifically requesting comments on:
(1) New information on the historical and current status, range,
distribution, and population size of the Tobusch fishhook cactus,
including the locations of any additional populations.
(2) New information on the known and potential threats to the
Tobusch fishhook cactus.
(3) New information regarding the life history, ecology, and
habitat use of the Tobusch fishhook cactus.
Please note that submissions merely stating support for or
opposition to the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act (16 U.S.C.
1531 et seq.) directs that determinations as to whether any species is
an endangered or threatened species must be made ``solely on the basis
of the best scientific and commercial data available.''
You may submit your comments and materials concerning the proposed
rule by one of the methods listed in ADDRESSES. Comments must be
submitted to https://www.regulations.gov before 11:59 p.m. (Eastern
Time) on the date specified in DATES. We will not consider hand-
delivered comments that we do not receive, or mailed comments that are
not postmarked, by the date specified in DATES.
We will post your entire comment--including your personal
identifying information--on https://www.regulations.gov. If you provide
personal identifying information in your comment, you may request at
the top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on https://www.regulations.gov, or by
appointment, during normal business hours at the U.S. Fish and Wildlife
Service, Austin Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Public Hearing
Section 4(b)(5)(E) of the Act provides for one or more public
hearings on this proposed rule, if requested. We must receive requests
for public hearings, in
[[Page 95933]]
writing, at the address shown in FOR FURTHER INFORMATION CONTACT by the
date shown in DATES. We will schedule public hearings on this proposal,
if any are requested, and places of those hearings, as well as how to
obtain reasonable accommodations, in the Federal Register at least 15
days before the first hearing.
Peer Review
In accordance with our policy, ``Notice of Interagency Cooperative
Policy for Peer Review in Endangered Species Act Activities,'' which
was published on July 1, 1994 (59 FR 34270), we are soliciting the
expert opinion of at least three appropriate independent specialists
regarding scientific data and interpretations contained in the Species
Status Assessment Report (SSA Report) (Service 2016; available at
https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0130)
supporting this proposed rule. The purpose of such review is to ensure
that our decisions are based on scientifically sound data, assumptions,
and analysis. We will incorporate, as appropriate, the feedback from
the peer review of the SSA Report into any final determination
regarding the subspecies.
Background
Section 4(b)(3)(B) of the Act 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 reclassifying a species may be warranted, we make a finding within
12 months of the date of receipt of the petition (``12-month
finding''). In this finding, we determine whether the petitioned action
is: (1) Not warranted, (2) warranted, or (3) warranted, but immediate
proposal of a regulation implementing the petitioned action is
precluded by other pending proposals to determine whether species are
endangered or threatened, and expeditious progress is being made to add
or remove qualified species from the Federal Lists of Endangered and
Threatened Wildlife and Plants. We must publish these 12-month findings
in the Federal Register. This document represents:
Our 12-month warranted finding on a July 16, 2012,
petition to reclassify the Tobusch fishhook cactus from endangered to
threatened (that is, to ``downlist'' this plant);
Our determination that the Tobusch fishhook cactus no
longer meets the definition of endangered under the Act; and
Our proposed rule to reclassify the Tobusch fishhook
cactus from endangered to threatened on the Federal List of Endangered
and Threatened Plants.
Previous Federal Actions
We published a final rule to list the Tobusch fishhook cactus as an
endangered species under the Act on November 7, 1979 (44 FR 64736). At
that time, we also determined that it was not prudent to designate
critical habitat for the subspecies because the publication of critical
habitat maps could make the species more vulnerable to taking. We
issued a recovery plan on March 18, 1987. The recovery plan has not
been revised. A status review (``5-year review'') under section
4(c)(2)(A) of the Act was completed for the Tobusch fishhook cactus on
January 5, 2010. The 5-year review recommended that this plant be
reclassified from endangered to threatened (Service 2010).
On July 16, 2012, we received a petition dated July 11, 2012, from
The Pacific Legal Foundation, Jim Chilton, the New Mexico Cattle
Growers' Association, New Mexico Farm & Livestock Bureau, New Mexico
Federal Lands Council, and Texas Farm Bureau requesting, among other
things, that the Tobusch fishhook cactus be reclassified as threatened
based on the analysis and recommendation contained in the 5-year
review. The Service published a 90-day finding on September 9, 2013 (78
FR 55046) that the petition contained substantial scientific or
commercial information indicating that the petitioned action may be
warranted. On November 20, 2015, the Service received a complaint (New
Mexico Cattle Growers' Association et al. v. United States Department
of the Interior et al., No. 1:15-cv-01065-PJK-LF (D. N.M.)) for
declaratory judgment and injunctive relief from the New Mexico Cattle
Growers' Association, Jim Chilton, New Mexico Farm & Livestock Bureau,
New Mexico Federal Lands Council, and Texas Farm Bureau to, among other
things, compel the Service to make a 12-month finding on the petition.
This document serves as our 12-month warranted finding on the July 16,
2012, petition to reclassify the Tobusch fishhook cactus from
endangered to threatened.
Species Status Assessment for Tobusch fishhook cactus.
We prepared a Species Status Assessment (SSA) for the Tobusch
fishhook cactus (Service 2016; available at https://www.regulations.gov), which includes a thorough review of the
subspecies' taxonomy, natural history, habitats, ecology, populations,
and range. The SSA analyzes individual, population, and subspecies
requirements, as well as factors affecting the subspecies' survival and
its current conditions, to assess the subspecies' current and future
viability in terms of resilience, redundancy, and representation.
We define viability as the ability of a species to persist and to
avoid extinction over the long term. Resilience refers to the
population size and demographic characteristics necessary to endure
stochastic environmental variation (Shaffer and Stein 2000, pp. 308-
310). Resilient populations are better able to recover from losses
caused by random variation, such as fluctuations in recruitment
(demographic stochasticity), variations in rainfall (environmental
stochasticity), or changes in the frequency of wildfires. Redundancy
refers to the number and geographic distribution of populations or
sites necessary to endure catastrophic events (Shaffer and Stein 2000,
pp. 308-310). As defined here, catastrophic events are rare
occurrences, usually of finite duration, that cause severe impacts to
one or more populations. Examples of catastrophic events include
tropical storms, unusually high or prolonged floods, prolonged drought,
and unusually intense wildfire. Species that have multiple resilient
populations distributed over a larger landscape are more likely to
survive catastrophic events, since not all populations would be
affected. Representation refers to the genetic diversity, both within
and among populations, necessary to conserve long-term adaptive
capability (Shaffer and Stein 2000, pp. 307-308). Species with greater
genetic diversity are more able to adapt to environmental changes and
to colonize new sites.
The SSA Report provides the scientific basis that informs our
regulatory determination as to whether or not this subspecies should be
listed as an endangered or a threatened species under the Act. This
decision involves the application of standards within the Act, the
Act's implementing regulations, and Service policies (see Finding and
Proposed Determination, below). The following discussion is a summary
of the results and conclusions from the SSA Report. We are soliciting
peer review of the draft SSA Report from three objective and
independent scientific experts.
Description
Tobusch fishhook cactus is a rare, endemic plant of the Edwards
Plateau of central Texas. The common and scientific names honor Herman
[[Page 95934]]
Tobusch, who first collected it in 1951 (Marshall 1952, p. 78). In the
wild, this globose or columnar cactus rarely exceeds 5 centimeters (2
inches) in diameter and in height (Poole and Janssen 2002, p. 7). As
the name implies, it is armed with curved ``fishhook'' spines.
Classification
The taxonomic classifications of Tobusch fishhook cactus include
several published synonyms. We listed it as a species, Ancistrocactus
tobuschii (44 FR 64736, November 7, 1979), and retained this
classification for the recovery plan (Service 1987). However, recent
phylogenetic evidence supports classifying Tobusch fishhook cactus as
subspecies tobuschii of Sclerocactus brevihamatus (Porter and Prince
2011, pp. 40-47). It is distinguished morphologically from its closest
relative, S. brevihamatus ssp. brevihamatus, on the basis of yellow
versus pink- or brown-tinged flowers, fewer radial spines, and fewer
ribs (Marshall 1952, p. 79; Poole et al. 2007, p. 442; Porter and
Prince 2011, pp. 42-45). Additionally, S. brevihamatus ssp. tobuschii
is endemic to limestone outcrops of the Edwards Plateau, while S.
brevihamatus ssp. brevihamatus occurs in alluvial soils in the
Tamaulipan Shrublands and Chihuahuan Desert. A recent investigation
confirmed genetic divergence between the two subspecies, although they
may interact genetically in a narrow area where their ranges overlap
(Rayamajhi 2015, pp. 67, 98; Sharma 2015, p. 1). With the publication
of this proposed rule, we officially accept the new scientific name of
the Tobusch fishhook cactus as Sclerocactus brevihamatus ssp.
tobuschii.
Reproduction
Tobusch fishhook cactus grows slowly, reaching a reproductive size
of about 2 centimeters (0.8 inches) in diameter after 9 years (Emmett
1995, pp. 168-169). It flowers between late January and mid-March, and
its major pollinators are honey bees and halictid bees (Emmett 1995,
pp. 74-75; Lockwood 1995, pp. 428-430; Reemts and Becraft 2013, pp. 6-
7; Langley 2015, pp. 21-23). The breeding system is primarily out-
crossing, requiring two individuals for reproduction, but the
subspecies is capable of self-fertilization (Emmett 1995, p. 70;
Langley 2015, pp. 24-28). Reproductive individuals produce an average
of 112 seeds per year (Emmett 1995, p. 108). Ants may be seed
predators, dispersers, or both (Emmett 1995, pp. 112-114, 124). Mammals
or birds may also accomplish longer distance seed dispersal (Emmett
1995, pp. 115-116, 126). There is little evidence that seeds persist in
the soil (Emmett 1995, pp. 120-122).
Habitats
When listed as endangered in 1979, fewer than 200 individuals of
Tobusch fishhook cactus were known from 4 riparian sites, 2 of which
had been destroyed by floods (44 FR 64736, November 7, 1979; Service
1987, pp. 4-5). We now understand that those riparian habitats were
atypical; the great majority of populations that have now been
documented occur in upland sites dominated by Ashe juniper-live oak
woodlands and savannas on the Edwards Plateau (Poole and Janssen 2002,
p. 2). Soils are classified in the Tarrant, Ector, Eckrant, and similar
series. Within a matrix of woodland and savanna, the subspecies occurs
in discontinuous patches of very shallow, gravelly soils where bare
rock and rock fragments comprise a large proportion of the surface
cover (Sutton et al. 1997, pp. 442-443). Associated vegetation includes
small bunch grasses and forbs. The subspecies' distribution within
habitat patches is clumped and tends to be farther from woody plant
cover (Reemts 2014, pp. 9-10). The presence of cryptograms, primitive
plants that reproduce by spores rather than seeds, may be a useful
indicator of fine-scale habitat suitability (Service 2010, p. 17).
Wildfire (including prescribed burning) causes negligible damage to
Tobusch fishhook cactus populations (Emmett 1995, p. 42; Poole and
Birnbaum 2003, p. 12). The subspecies probably does not require fire
for germination, establishment, or reproduction, but periodic burning
may be necessary to prevent the encroachment of woody plants into its
habitats.
Populations and Range
A population of an organism is a group of individuals within a
geographic area that are capable of interbreeding or interacting.
Although the term is conceptually simple, it may be difficult to
determine the extent of a population of rare or cryptic species, and
this is certainly the case for Tobusch fishhook cactus. Thorough
surveys on public lands, such as state parks and highway rights-of-way,
have detected groups of individuals, but since the vast majority of the
surrounding private lands have not been surveyed, we do not know if
these are small, isolated populations, or parts of larger interacting
populations or meta-populations. For convenience, we often informally
use the terms ``site'', referring to a place where the species was
found, and ``colony'', referring to a cluster of individuals, when we
do not know the extent of the local population.
Tobusch fishhook cactus populations are now confirmed in eight
central Texas counties: Bandera, Edwards, Kerr, Kimble, Kinney, Real,
Uvalde, and Val Verde. In 2009, the Texas Native Diversity Database
listed 105 element occurrences, areas in which the species was present,
(EOs; NatureServe 2002, p. 10) of Tobusch fishhook cactus, totaling
3,395 individuals (TXNDD 2009, pp. 1-210). Texas Parks and Wildlife
Department botanists monitored 118 permanent plots at 12 protected
natural areas from 1991 through 2013 (Poole and Janssen 2002, entire;
Poole and Birnbaum 2003, entire). Annual mortality in plots was often
greater than 20 percent, and consistently exceeded recruitment (Emmett
1995, pp. 155-161; Poole and Birnbaum 2001, p. 5). In particular,
infestations by insect larvae caused catastrophic population declines
(Emmett 1995, pp. 155-161; Calvert 2003, entire). However, mortality
and recruitment determinations are confounded by the great difficulty
in detecting live plants in the field (Poole and Janssen 2002, p. 5;
Reemts 2014, pp. 1, 8). Despite the decline of many individual
colonies, the total known population sizes have steadily increased, due
to the discovery of previously undetected individuals and colonies.
Summary of Subspecies Requirements
Requirements of Individuals
Tobusch fishhook cactus plants occur in patches of very shallow,
rocky soil overlying limestone. The immediate vicinity of plants is
sparsely vegetated with small bunch grasses and forbs and there is
little or no woody plant cover. Individuals require an estimated 9
years to reach a reproductive size of about 2 centimeters (0.8 inches)
in diameter. Reproduction is primarily by out-crossing between
unrelated individuals, and the known pollinators include honey bees and
halictid bees. Out-crossing requires genetically diverse cactus
populations within the foraging range of pollinators, and is less
likely to occur in small, isolated populations. Healthy pollinator
populations, in turn, require intact, diverse, native plant
communities. Halictid bees are frequent natural pollinators of the
Tobusch fishhook cactus. Given their relatively small size, we expect
the foraging range of these bees to be fairly limited. Therefore, the
health and diversity of native vegetation within the vicinity of
Tobusch fishhook cactus plants (a range
[[Page 95935]]
of 50 to 500 meters (m) (164 to 1,640 feet (ft)) may be particularly
important for successful cactus reproduction. Healthy pollinator
populations also require the least possible exposure to agricultural
pesticides within their foraging ranges.
Requirements of Populations
Population persistence requires stable or increasing demographic
trends. Although some Tobusch fishhook cactus individuals live for
decades, annual mortality rates are often greater than 20 percent, and
relatively few individuals live long enough to reproduce. Mortality
within monitored colonies often exceeds recruitment, and some colonies
have died out. Nevertheless, even where individual colonies have
collapsed, the total documented population sizes at many protected
natural areas are stable or increasing, due to discoveries of new
individuals and colonies. Therefore, the assessment of demographic
trends depends on how populations are delineated; we conclude that it
is more appropriate to track the collective populations of multiple
colonies that interact on a landscape scale (i.e., meta-populations).
Meta-population persistence requires recruitment of new colonies, and/
or reestablishment at sites of former colonies that previously
collapsed. A major cause of mortality is infestation by insect larvae,
mainly by an undescribed species of Gerstaeckeria (cactus weevil), and
one or more species of cactus longhorn beetles (Moneilema spp.). The
adults of these parasites are flightless, so their dispersal to new
colonies is likely to be very limited. When individual colonies of the
cactus die off, the parasites also die off, rendering those patches of
suitable habitat available for cactus re-colonization. Hence, these
periodic infestations of parasite larvae greatly influence the
population dynamics of the Tobusch fishhook cactus. The distance
between colonies has two opposing effects on their persistence. Greater
distance reduces susceptibility to parasite infestation, but also
reduces the amount of gene flow, by means of pollinators vectoring
pollen, or through seed dispersal, between colonies. Thus, the
persistence of entire meta-populations would require fairly large
landscapes where discontinuous patches of suitable habitat are
distributed and populated at a density just low enough to hold the
parasites at bay, but just high enough for halictid bees and other
pollinators and seed dispersers to vector genes between them.
One measure of population resilience is minimum viable population
(MVP), which is an estimate of the minimum population size that has a
high probability of enduring a specified period of time. Poole and
Birnbaum (2003, p. 1) estimated an MVP of 1,200 individuals for the
Tobusch fishhook cactus, using a surrogate species approach (Pavlik
1996, pp. 136-137). For the reasons explained above, MVP levels are
more appropriately applied to meta-populations rather than individual
colonies of this cactus.
The degree of genetic diversity within Tobusch fishhook cactus
populations is important for several reasons. First, diversity within
populations should confer greater resistance to pathogens and
parasites, and greater adaptability to environmental stochasticity
(random variations, such as annual rainfall and temperature patterns)
and climate changes. Second, low genetic diversity within interbreeding
populations leads to a higher incidence of inbreeding, and potentially
to inbreeding depression. Finally, the breeding system of the Tobusch
fishhook cactus is primarily out-crossing, so populations with too
little genetic diversity would produce fewer progeny.
Fire, whether natural or prescribed, appears to have little effect
on individual Tobusch fishhook cactus plants. This is because the
plants occur where vegetation is very sparse, and the plants protrude
very little above the ground and are protected by surrounding rocks
from the heat of vegetation burning nearby. On the other hand, periodic
fire is likely to be necessary for population persistence to reduce
juniper encroachment into suitable habitats. Furthermore, the diverse
shrub and forb vegetation that sustains healthy pollinator populations
is maintained by periodic wildfire; without fire, dense juniper groves
frequently displace these shrubs and forbs. Hence, if the native plant
diversity of entire landscapes surrounding Tobusch fishhook cactus
populations succumbs to juniper encroachment, pollinator populations
will likely decline, and reproduction of the Tobusch fishhook cactus
and gene flow between its colonies may be reduced.
Subspecies Requirements
In addition to population resilience (described above under
``Requirements of Individuals'' and ``Requirements of Populations''),
we assess the subspecies' viability in terms of its redundancy and
representation.
Given that insect parasites are able to devastate large, dense
populations, a few large populations are much more vulnerable than many
small populations. The resilience of the Tobusch fishhook cactus
derives not merely from the size of meta-populations, but also their
density. Meta-populations with a low density of colonies may incur loss
of genetic diversity and increased potential for inbreeding.
Conversely, vulnerability to insect parasitism increases when meta-
populations become too dense, or when individual colonies become too
large. Assessments of resilience (meta-population size and
demographics) and redundancy (number of meta-populations within
representative areas) depend on how meta-populations are delineated. We
believe that there must be some optimal range of meta-population
density, i.e. the distance between meta-populations, and of colony
size, although we do not currently know what those are.
Representation reflects the genetic diversity, both within and
among populations, necessary to conserve long-term adaptive capability
(Shaffer and Stein 2000, pp. 307-308). Genetic diversity within a
population can be measured by the numbers of variant forms of genes
represented in that population. One measure of this within-population
genetic diversity is called heterozygosity; possible values range from
0 (all members of a population are genetically identical for specified
genes) to 1.0 (all members of a population a genetically different).
Another useful measure is the inbreeding coefficient (FIS),
which ranges from -1 (all members of the population are heterozygous,
containing two forms of specific genes, and there is no evidence of
inbreeding) to 1.0 (all members are homozygous, containing only one
form of specific genes, and inbred). Although there are no
heterozygosity levels or inbreeding coefficients that are considered
healthy for all species, we may assess the genetic health of the
Tobusch fishhook cactus by comparison to the observed values of
reference species, such as other cactus species with similar life
histories that are abundant and widespread (Rayamajhi 2015, pp. 56, 63;
Schwabe et al. 2015, pp. 449, 454-455). The array of different
environments in which a species occurs, such as the riparian and upland
sites where Tobusch fishhook cactus is found, can also be used as a
proxy measure for genetic diversity and therefore representation
(Shafer and Stein 2000, p. 308).
Review of the Recovery Plan
Section 4(f) of the Act directs us to develop and implement
recovery plans for the conservation and survival of endangered and
threatened species
[[Page 95936]]
unless we determine that such a plan will not promote the conservation
of the species. Recovery plans identify site-specific management
actions that will achieve recovery of the species, measurable criteria
that set a trigger for review of the species' status, and methods for
monitoring recovery progress.
Recovery plans are not regulatory documents; instead they are
intended to establish goals for long-term conservation of listed
species and define criteria that are designed to indicate when the
threats facing a species have been removed or reduced to such an extent
that the species may no longer need the protections of the Act, as well
as actions that may be employed to achieve reaching the criteria. There
are many paths to accomplishing recovery of a species, and recovery may
be achieved without all criteria being fully met or all actions fully
implemented. Recovery of a species is a dynamic process requiring
adaptive management that may, or may not, fully follow the guidance
provided in a recovery plan.
The Tobusch fishhook cactus recovery plan was approved by the
Service on March 18, 1987 (Service 1987). Delisting criteria were not
established in the recovery plan. However, the recovery plan
established a criterion of 3,000 individuals in each of four safe sites
for reclassification from endangered to threatened.
We now understand that insect parasites are able to devastate
large, dense populations and we conclude that a few large populations
are much more vulnerable than many small populations; therefore, this
recovery criterion should be amended. Currently, many small populations
exist, and surveyors have documented 3,395 Tobusch fishhook cactus
individuals at 105 element occurrences (EOs) in 8 counties of the
Edwards Plateau, including 12 sites managed either by the state or
conservation organizations, where monitored populations ranged from 34
to 1,090 individuals.
Summary of Factors Affecting the Subspecies
Section 4 of the Act and its implementing regulations (50 CFR part
424) set forth the procedures for listing species, reclassifying
species, or removing species from listed status. A species may be
determined to be an endangered or threatened species due to one or more
of the five listing factors described in section 4(a)(1) of the Act:
(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. A
species may be reclassified or delisted on the same basis.
Consideration of these factors was incorporated into the Tobusch
fishhook cactus SSA (Service 2016; available at https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0130) and projected
in future scenarios to evaluate viability of the Tobusch fishhook
cactus. The effects of conservation measures were also assessed as part
of the current condition of the Tobusch fishhook cactus in the SSA
Report, and those effects were projected in future scenarios.
Land Use Changes (Factor A)
Relatively little urban and industrial development is occurring
within the semi-arid, sparsely populated eight-county known range of
the Tobusch fishhook cactus. However, a significant ongoing trend
throughout the subspecies' range is the subdivision of large ranches
leading to a proliferation of roads, fences, power lines, and
residential development, all of which contribute incrementally to
habitat loss and fragmentation.
The predominant, historic land use throughout the Edwards Plateau
has been livestock grazing. In many cases, poor rangeland management
during the last century has caused the depletion of herbaceous
vegetation, cessation of the natural wildfire cycle, proliferation of
dense juniper stands, soil erosion, and reduced infiltration and
storage of rainwater in the soil profile; all of these changes are
likely to have harmed Tobusch fishhook cactus populations. The change
to a primarily recreational land use often entails continued grazing,
but at a sustainable stocking density.
Prescribed burning may be one of the most important vegetation
management tools for sustaining Tobusch fishhook cactus populations
because it reduces woody vegetation encroachment. However, the
proliferation of residential development within the species' habitat
makes this tool more challenging for natural resource managers to use.
Changes in Vegetation and Wildfire Frequency (Factor A)
Bray (1904, pp. 14-15, 23-24) documented the rapid transition of
grasslands to woodlands in the Edwards Plateau occurring more than a
century ago; he attributed this change to overgrazing, the depletion of
grasses, and the cessation of wildfires. Fonteyn et al. (1988, p. 79)
state that savannas covered portions of the pre-settlement Edwards
Plateau, and since 1850 were transformed to shrubland or woodland
``primarily by suppression of recurring natural and anthropogenic fires
and the introduction of livestock.'' They list the fire-sensitive Ashe
juniper (Juniperus ashei) as the most successful of many woody plants
that have invaded grasslands. Reemts (2014 p. 1) lists the encroachment
of woody plants into the rocky, open habitat as one of several
remaining habitat-related threats that endanger the Tobusch fishhook
cactus.
Livestock Grazing (Factor A)
The recovery plan stated, ``Ancistrocactus tobuschii plants have
been observed that were either uprooted or had apical meristem injuries
from livestock trampling.'' Nevertheless, livestock trampling and
herbivory have not subsequently been identified as significant causes
of mortality or damage to Tobusch fishhook cactus plants. Their
recurved spines and small size probably protect Tobusch fishhook cactus
plants from livestock herbivory. Livestock are not attracted to the
sparsely vegetated outcrops where Tobusch fishhook cactus plants
typically occur, and the plants are often nestled among larger rocks.
While livestock trampling probably occurs in grazed habitats, we have
no evidence that it represents a significant threat to the subspecies.
A number of healthy Tobusch fishhook cactus populations occur on well-
managed rangeland. We conclude that properly managed livestock grazing,
especially where juniper thinning and prescribed burning are used to
manage rangeland, is generally compatible with conservation of this
cactus.
Illegal Collection (Factor B)
Many rare cactus populations have been depleted by overzealous
collectors. The recovery plan lists illegal collection as a threat to
the subspecies. Westlund (1991, pp. 2, 35, 39) found six specimens of
Tobusch fishhook cactus, grown legally from seed, for sale in
commercial nurseries. Poole and Janssen (2002, p. 9) noted that one
population of the Tobusch fishhook cactus was heavily depleted by
collection, but concluded that ``collection is not currently perceived
to be a grave threat.'' Although illegal collection has not
significantly impacted the subspecies, the wild populations openly
accessed by the public remain vulnerable. The potential threat of
illegal collection might be diminished if seeds and plants of legally
propagated Tobusch fishhook cacti
[[Page 95937]]
become easier and less expensive to obtain than wild-dug specimens.
Parasites (Factor C)
The Tobusch fishhook cactus weevil (Gerstaeckeria spp.) and cactus
longhorn beetle (Moneilema spp.) parasitize and kill Tobusch fishhook
cactus plants and have contributed significantly to drastic declines in
many of the known populations (Calvert 2003, entire).
Periodic outbreaks of insect parasitism appear to be an unavoidable
natural cycle. For this reason, large cactus populations could
eventually host very large parasite populations, leading to their
collapse. The most appropriate conservation strategy may be to protect
larger numbers of small, widely spaced meta-populations, rather than
fewer large populations that are more vulnerable to parasites.
Other Herbivory (Factor C)
Poole and Birnbaum (2003, pp. 11-12) report that jackrabbits browse
the cactus, but in most sites cause less than 2 percent mortality. If
the root systems are not too badly damaged, they may regenerate one or
more new stems. Feral hogs have uprooted plants in many sites (also
observed by Reemts (2015, p. 1)). An unidentified ant species has also
caused 1 percent mortality at some sites by creating mounds on top of
the stems. With the exception of feral hogs, herbivory does not appear
to be a significant cause of mortality or damage to Tobusch fishhook
cactus plants.
Inadequacy of Existing Regulatory Mechanisms (Factor D)
Federally listed plants occurring on private lands have limited
protection under the Act, unless also protected by state laws; the
State of Texas also provides very little protection to listed plant
species on private lands. Approximately 95 percent of Texas land area
is privately owned. It is reasonable to assume that the vast majority
of existing Tobusch fishhook cactus habitat, including sites that have
not been documented, occurs on private land. Therefore, most of the
subspecies' populations and habitats are not subject to Federal or
state protection unless there is a Federal nexus, such as provisions of
the Clean Water Act (33 U.S.C. 1251 et seq.) or a federally funded
project.
Demographic Consequences of Small Population Size and Density (Factor
E)
Poole and Birnbaum (2003, p. 1) estimated an MVP of 1,200
individuals (Service 2016, section II.7.5, available at https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0130). For Tobusch
fishhook cactus, MVP levels are more appropriately applied to meta-
populations rather than individual colonies. Small populations are less
able to recover from losses caused by random environmental changes
(Shaffer and Stein 2000, pp. 308-310), such as fluctuations in
recruitment (demographic stochasticity), variations in rainfall
(environmental stochasticity), or changes in the frequency of
wildfires. The Tobusch fishhook cactus has a predominantly out-crossing
breeding system. The probability of successful fertilization between
unrelated individuals is reduced in small, isolated populations. The
remaining plants would produce fewer viable seeds, further reducing
population recruitment and engendering a downward spiral toward
extirpation. The demographic consequences of small population size are
compounded by genetic consequences (discussed below), because reduced
out-crossing corresponds to increased inbreeding. In addition to
population size, it is likely that population density within meta-
populations also influences population viability; density must be high
enough for gene flow within meta-populations, but low enough to
minimize parasite infestations.
Genetic Consequences of Small Population Sizes (Factor E)
Small, reproductively isolated populations are susceptible to the
loss of genetic diversity, to genetic drift, and to inbreeding. The
loss of genetic diversity may reduce the ability of a species or
population to resist pathogens and parasites, to adapt to changing
environmental conditions, or to colonize new habitats. Conversely,
populations that pass through a ``genetic bottleneck'', i.e. a time of
significant loss of genetic diversity, may subsequently benefit through
the elimination of harmful alleles, or the variant forms of a given
gene. Nevertheless, the net result of loss of the genetic diversity is
likely to be a loss of fitness and lower chance of survival of
populations and of the subspecies.
Genetic drift is a change in the frequencies of alleles in a
population over time. Genetic drift can arise from random differences
in founder populations, i.e. new populations originally established by
a very small number of individuals, and the random loss of rare alleles
in small, isolated populations. Genetic drift may have a neutral effect
on fitness, or contribution to the gene pool, in larger populations,
but may cause the loss of genetic diversity in small populations.
Genetic drift may also result in the adaptation of an isolated
population to the climates and soils of specific sites, leading to the
development of distinct genotypes that are specifically adapted to a
particular ecological area and to speciation, or the evolution of new
species. For example, the genetic divergence of Sclerocactus
brevihamatus ssp. brevihamatus and S. brevihamatus ssp. tobuschii
(Rayamajhi 2015, pp. 67, 98; Service 2016, pp. 6-7, available at https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0130) may have
resulted when populations of the species brevihamatus migrated into
separate geographic regions, and once separated, each population
adapted to different soils, climate, and pollinator species.
Inbreeding depression is the loss of fitness among offspring of
closely related individuals. While most animal species are susceptible
to inbreeding depression, plant species vary greatly in response to
inbreeding. Levels of inbreeding can be measured with the inbreeding
coefficient (FIS), which ranges from -1 (all members of the
population are heterozygous for specific genes and there is no evidence
of inbreeding) to 1.0 (all members are homozygous and inbred).
Rayamajhi (2015, pp. 63-64) found relatively high inbreeding
coefficients in three of eight populations, which he attributed to
mating of close relatives within small, isolated populations.
Nevertheless, we do not know to what extent inbreeding has reduced
fitness of these populations.
Land Ownership (Factor E)
A large portion of the known individuals and populations of the
Tobusch fishhook cactus occurs on privately owned land. This does not
constitute a direct threat to the subspecies, and many landowners have
demonstrated interest and enthusiasm for its conservation. However,
private ownership makes conservation more challenging for several
reasons. Access to populations and habitats is subject to the interests
of hundreds of individual landowners. Consequently, our knowledge of
the subspecies' actual status is far from complete. Establishing and
maintaining cooperative relationships with large numbers of private
landowners is time-consuming, and these important relationships may
lapse when personnel of conservation organizations retire or pursue
other career choices. The ownership of private lands changes hands over
time, and future owners may choose not to continue conservation efforts
that were supported by previous owners. Hence, it
[[Page 95938]]
is difficult to assure permanent conservation on private lands. These
challenges underscore the importance of effective landowner outreach in
the conservation of the Tobusch fishhook cactus.
Climate Change (Factor E)
The Fifth Assessment Report of the Intergovernmental Panel on
Climate Change (IPCC) (IPCC 2013, p. 23) projects the following changes
by the end of the 21st century, relative to the 1986 to 2005 averages:
It is virtually certain that most land areas will experience warmer
and/or fewer cold days and nights; it is virtually certain that most
land areas will experience warmer and/or more frequent hot days and
nights; it is very likely that the frequency and/or duration of warm
spells and heat waves will increase in most land areas; it is very
likely that the frequency, intensity, and/or amount of heavy
precipitation will increase in mid-latitude land masses; it is likely
that the intensity and/or duration of droughts will increase on a
regional to global scale. The magnitude of projected changes varies
widely, depending on which scenario of future greenhouse gas emissions
is used.
To evaluate how the climate of Tobusch fishhook cactus habitats may
change, we used the National Climate Change Viewer (U.S. Geological
Survey 2015) to compare past and projected future climate conditions
for Edwards County, Texas. The baseline for comparison was the observed
mean values from 1950 through 2005, and 30 climate models were used to
project future conditions for 2050 through 2074. We selected the
climate parameters of August maximum temperature, January minimum
temperature, annual mean precipitation, and annual mean evaporative
deficit. These particular parameters were selected from those available
because they represented those most likely to impact the survival of
individuals. The highest temperature of the year (August maximum
temperature) could potentially affect individuals by exacerbating the
effects of drought and the lowest temperatures of the year (January
minimum temperature) could expose individuals to freezing temperatures.
The annual mean precipitation and evaporative deficit provide measures
of drought that could negatively affect individuals. The results are
described in detail in the SSA Report (Service 2016, available at
https://www.regulations.gov under Docket No. FWS-R2-ES-2016-0130), but
generally, these models project that plant growth and survival in
Edwards County will become more moisture-limited, although the degree
of change varies under different scenarios.
Nevertheless, we do not know how the Tobusch fishhook cactus
responded to prior climate changes, nor can we determine how these
projected climate changes will affect the Tobusch fishhook cactus and
its habitat. Warmer winters could extend the growing season and improve
reproduction and survival of the Tobusch fishhook cactus, but might
also increase survival of parasite larvae. Heavier, less frequent
rainfall could reduce establishment of Tobusch fishhook cactus
seedlings, but perhaps less so than the bunch grasses with which it
competes. Zaya et al. (2014, pp. 37-38) projected that climate changes
will be detrimental to 4 populations, due primarily to lower survival
and reproduction, and beneficial to 6 others, given increased
individual growth rates. Thus, although it is likely that the projected
climate changes will affect the survival of the Tobusch fishhook cactus
in infinitely complex ways, we do not currently know what the net
result of beneficial and detrimental effects will be.
Conservation Efforts
Support for the recovery of Tobusch fishhook cactus has come from a
variety of sources. Conservation measures from nine formal
consultations under section 7 of the Act supported scientific
investigations, the salvage of individuals that would have been
destroyed by development, and contributions to the Tobusch Fishhook
Cactus Conservation Fund (Fund). The Lady Bird Johnson Wildflower
Center manages the Fund through a memorandum of agreement with the
Service. The Fund supported three projects that contributed
significantly to our knowledge of the Tobusch fishhook cactus. These
three Tobusch fishhook cactus projects included a study on the effects
of shading by woody shrubs, a conservation genetics study, and
population viability analyses. Five grants under section 6 of the Act
have supported scientific investigations and extensive inventory and
monitoring of the subspecies on state highway rights-of-way, in state
parks, in wildlife management areas, and in state natural areas. Four
graduate-level investigations focused on the Tobusch fishhook cactus,
leading to three Master's theses and a doctoral dissertation, and
provided information that is essential to the subspecies' conservation
and recovery.
Current Status
By 2009, surveyors documented 3,395 Tobusch fishhook cactus
individuals at 105 E.O.s in 8 counties of the Edwards Plateau. This
includes 12 sites managed either by the state or conservation
organizations where monitored populations ranged from 34 to 1,090
individuals, and totaled 3,139 individuals. Recent surveys found 660
new Tobusch fishhook cactus individuals that probably represent many
new E.O.s, bringing the total documented number of individuals (based
on the most recent surveys) to over 4,000.
We developed a model of potential habitat based on the soil types
and watersheds of documented populations. This model predicts that over
2 million hectares (ha) (5 million acres (ac)) of potential habitat
occurs in the eight counties of the cactus' currently known range, as
well as in some adjacent counties (mainly Crockett and Sutton
Counties). However, we have no records of the Tobusch fishhook cactus
occurring in any of these adjacent counties, nor have any surveys for
the subspecies been conducted there, to our knowledge. Within these
areas of potential habitat, only a small fraction of the total area
contains suitable habitat, consisting of discontinuous, open areas on
or near exposed limestone strata. Based on 25 surveys widely
distributed across the subspecies range, we calculated an average
density across the range of the species. That average density was
applied to the amount of suitable habitat and used to calculate an
estimate of the global population. We estimate that the global
population is about 480,000 individuals (Service 2016, Appendix B,
available at https://www.regulations.gov under Docket No. FWS-R2-ES-
2016-0130).
From 1991 through 2013, many individual colonies of the Tobusch
fishhook cactus declined and some have died out completely. A principle
cause of colony decline is parasitism by the larvae of flightless
insects, including an undescribed species of Gerstaeckeria (a cactus
weevil) and one or more species of Moneilema (cactus longhorn beetles).
At the same time, total populations in monitored sites (consisting of
multiple colonies; meta-populations) have remained steady or have
increased, due to the discovery of new colonies or re-colonization of
formerly depleted colonies. We believe that the Tobusch fishhook cactus
co-evolved with these parasitic organisms, and that they are important
drivers of its population dynamics. Large, dense cactus populations
become susceptible to larval parasitism and decline until parasite
populations cannot be sustained. Meta-populations, consisting of
multiple, widely-dispersed colonies, appear to be stable; however, we
do not
[[Page 95939]]
know what the long-term demographic trends are at the meta-population
or subspecies level.
The expected heterozygosity (He) and observed
heterozygosity (Ho) are useful measures of within-population
genetic diversity; possible values range from 0 (all members of a
population are genetically identical for specified genes) to 1.0 (all
members of a population are genetically different). Rayamajhi (2015,
pp. 57-61, 64, 97) determined that the mean He for nine
populations of Sclerocactus brevihamatus ssp. tobuschii was 0.59, and
the mean Ho was 0.37. Through comparison to columnar cactus
species that are endemic or have limited geographic distribution, he
concluded that, for S. brevihamatus ssp. tobuschii, He was
moderately high, and Ho was moderate which suggest there is
sufficient genetic diversity to conserve long-term adaptive capability.
Another useful measure is the inbreeding coefficient
(FIS), which ranges from -1 (all members of the population
are heterozygous for specific genes and there is no evidence of
inbreeding) to 1.0 (all members are homozygous and inbred). For
Sclerocactus brevihamatus ssp. tobuschii, the mean FIS was
0.38 (range of 0.15 to 0.63) (Rayamajhi 2015). While most populations
had an apparently healthy degree of out-crossing, three populations of
S. brevihamatus ssp. tobuschii were at relatively higher risk of
inbreeding effects and may have suffered recent genetic bottlenecks
through population declines. The higher level of inbreeding in these
populations may be due to small, isolated populations; mating of close
relatives within populations; the limited range of seed dispersal; and
the limited range and foraging behavior of a primary pollinator,
halictid bees.
There were relatively few genetic differences between the nine
Tobusch fishhook cactus populations in Rayamajhi's study (2015),
regardless of the distance between populations. This evidence supports
a hypothesis that gene flow has occurred throughout the subspecies'
range, at least until recently; however, recently isolated populations
may not yet show genetic differentiation, in part because individuals
can live and contribute to the local gene pool at least for several
decades.
Assessment of Current and Future Viability
We estimate that about 480,000 individuals of Tobusch fishhook
cactus are distributed at low density over an area of more than 2
million ha (5 million ac). Thus, it is likely that the Tobusch fishhook
cactus has multiple, resilient populations. Although many individual
colonies have declined, meta-population levels of monitored areas
appear stable; however, we have very little data on meta-population
trends over the subspecies' entire range. Genetic data from wild
populations indicate that most populations, and the subspecies as a
whole, currently possess sufficient genetic diversity to conserve long-
term adaptive capability. Nevertheless, some small, isolated
populations have higher levels of inbreeding, and may as a consequence
suffer reduced fitness and reproduction. There is relatively little
genetic diversity between populations, which is evidence that gene flow
has occurred fairly recently between populations. Considering the
naturally low densities of Tobusch fishhook cactus populations, gene
flow among them may be easily disrupted.
Demographic population viability analyses (PVA) of monitoring plot
data predicted stable or increasing trends for two or three
populations, moderate declines for two populations, and large to
precipitous declines in five populations over the next 50 years (Zaya
et al. 2014, pp. 29-42). When expected climate changes were included in
these analyses, four populations responded negatively to climate
changes, and six populations responded positively (compared to PVA
without climate changes). These findings predict an overall decline in
subspecies viability over the 50 year time frame. However, we do not
know how well these analyses project the demographic trends of meta-
populations distributed over larger landscapes.
We project what the viability of the Tobusch fishhook cactus could
be, between 2050 and 2074, under three scenarios. We considered how
conservation support, the subspecies' geographic range, habitat
management, population management, and climate changes may contribute
to these scenarios. The first scenario represents improvements over
current conditions. The second scenario represents the most likely
conditions if current trends continue. The third scenario represents
deteriorating conditions. We conclude that under the most likely
scenario, the subspecies remains viable but requires continued
conservation, management, and protection.
Finding and Proposed Determination
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the Tobusch fishhook cactus. The Tobusch fishhook cactus was listed
as endangered in 1979, due to: Few known populations, habitat
destruction, and altered stream flows (Factor A); illegal collection
(Factor B); and very limited geographic range, small population sizes,
restricted gene pool, and lack of reproduction (Factor E). We now know
there are many more populations over a much wider area; about 4,000
individuals have been documented at more than 105 EOs. These data allow
us to estimate that the total population size is about 480,000
individuals distributed at low density over about 2 million ha (5
million ac). Most habitats are relatively secure, given that they are
in remote, rocky areas that are unsuitable for growing crops. However,
the great majority is on private lands that are becoming increasingly
fragmented and may be subject to destruction or modification. Many of
the known populations are small and isolated, and the monitored
portions of numerous populations have declined. Demographic population
viability analyses predict an overall future decline in subspecies'
viability. However, we do not know how well these analyses project the
demographic trends of meta-populations distributed over larger
landscapes. We know that insect parasites are a major cause of
mortality, and may naturally reduce populations to low densities. Many
populations have sufficient genetic diversity to confer long-term
adaptive capability, but some small, isolated populations have higher
levels of inbreeding and may be affected by reduced fitness and
reproduction. It is likely that projected climate changes will affect
the Tobusch fishhook cactus, but we do not currently know whether this
will have a net positive or negative effect on its viability.
We have determined that the Tobusch fishhook cactus' current
viability is higher than was known at the time of listing. Based on the
analysis in the SSA, and summarized above, we believe that the Tobusch
fishhook cactus does not meet the definition of endangered under the
Act. However, due to continued threats from the demographic and genetic
consequences of small population sizes and geographic isolation, insect
parasitism, feral hog depredation, and changes in the wildfire cycle
and vegetation, as well as unknown long-term effects of land use
changes and climate changes, we find that the Tobusch fishhook cactus
is likely to become an endangered species within the foreseeable future
throughout all of its range. Because we have found that the Tobusch
fishhook cactus
[[Page 95940]]
(Sclerocactus brevihamatus ssp. tobuschii; currently listed as
Ancistrocactus tobuschii) meets the definition of threatened under the
Act, we propose to reclassify it from endangered to threatened on the
Federal List of Endangered and Threatened Plants (List).
Significant Portion of the Range Analysis
Under the Act and our implementing regulations, a species may
warrant listing if it is in danger of extinction or likely to become so
throughout all or a significant portion of its range. We published a
final policy interpreting the phrase ``significant portion of its
range'' (SPR) (79 FR 37578; July 1, 2014). The final policy states
that: (1) If a species is found to be endangered or threatened
throughout a significant portion of its range, the entire species is
listed as endangered or threatened, respectively, and the Act's
protections apply to all individuals of the species wherever found; (2)
a portion of the range of a species is ``significant'' if the species
is not currently endangered or threatened throughout all of its range,
but the portion's contribution to the viability of the species is so
important that, without the members in that portion, the species would
be in danger of extinction, or likely to become so in the foreseeable
future, throughout all of its range; (3) the range of a species is
considered to be the general geographical area within which that
species can be found at the time the Service makes any particular
status determination; and (4) if a vertebrate species is endangered or
threatened throughout a significant portion of its range, and the
population in that significant portion is a valid distinct population
segment (DPS), we will list the DPS rather than the entire taxonomic
species or subspecies. Because we have determined that the Tobusch
fishhook cactus is threatened throughout all of its range, no portion
of its range can be ``significant'' for the purposes of the definitions
of ``endangered species'' and ``threatened species.''
Conclusion
Using the best available scientific information, we have determined
that the Tobusch fishhook cactus is not currently in danger of
extinction throughout all or a significant portion of its range, but is
likely to become endangered within the foreseeable future throughout
all of its range. In accordance with 50 CFR 424.11(c), we therefore
propose to reclassify the Tobusch fishhook cactus as threatened on the
Federal List of Endangered and Threatened Plants at 50 CFR 17.12(h).
Effects of the Rule
This proposal, if made final, would revise 50 CFR 17.12(h) to
reclassify the Tobusch fishhook cactus as threatened on the Federal
List of Endangered and Threatened Plants. There is no critical habitat
designated for this subspecies; therefore, this proposed rule would not
affect 50 CFR 17.96.
Required Determinations
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in ADDRESSES. To better help us
revise the rule, your comments should be as specific as possible. For
example, you should tell us the numbers of the sections or paragraphs
that are unclearly written, which sections or sentences are too long,
the sections where you feel lists or tables would be useful, etc.
National Environmental Policy Act
We have determined that environmental assessments and environmental
impact statements, as defined under the authority of the National
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.), need not be
prepared in connection with regulations pursuant to section 4(a) of the
Act. We published a notice outlining our reasons for this determination
in the Federal Register on October 25, 1983 (48 FR 49244).
References Cited
A complete list of all references cited in this proposed rule is
available at https://www.regulations.gov at Docket No. FWS-R2-ES-2016-
0130, or upon request from the Austin Ecological Services Field Office
(see FOR FURTHER INFORMATION CONTACT).
Authors
The primary authors of this proposed rule are staff members of the
Service's Austin Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, unless
otherwise noted.
0
2. Amend Sec. 17.12(h), the List of Endangered and Threatened Plants,
under FLOWERING PLANTS by:
0
a. Removing the entry for ``Ancistrocactus tobuschii''; and
0
b. Adding, in alphabetical order, an entry for ``Sclerocactus
brevihamatus ssp. tobuschii'' to read as follows:
Sec. 17.12 Endangered and threatened plants.
* * * * *
(h) * * *
[[Page 95941]]
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Listing citations and
Scientific name Common name Where listed Status applicable rules
----------------------------------------------------------------------------------------------------------------
FLOWERING PLANTS
* * * * * * *
Sclerocactus Tobusch fishhook Wherever found........ T 44 FR 64736; 11/7/
brevihamatus ssp. cactus. 1979, [Federal
tobuschii Register citation of
the final rule].
* * * * * * *
----------------------------------------------------------------------------------------------------------------
Dated: December 15, 2016.
Stephen Guertin,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2016-31296 Filed 12-28-16; 8:45 am]
BILLING CODE 4333-15-P