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]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[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]


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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.

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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]]



----------------------------------------------------------------------------------------------------------------
                                                                                           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