[Federal Register Volume 76, Number 37 (Thursday, February 24, 2011)]
[Proposed Rules]
[Pages 10299-10310]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-4121]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R6-ES-2010-0095; MO 92210-0-0008-B2]
Endangered and Threatened Wildlife and Plants: 90-Day Finding on
a Petition To List the Wild Plains Bison or Each of Four Distinct
Population Segments as Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service, announce a 90-day
finding on a petition to list the wild plains bison (Bison bison
bison), or each of four distinct population segments (DPSs), as
threatened under the Endangered Species Act of 1973, as amended (Act).
Based on our review, we find that the petition does not present
substantial information indicating that listing may be warranted.
Therefore, we are not initiating a status review in response to this
petition. However, we ask the public to submit to us any new
information that becomes available concerning the status of, or threats
to, the wild plains bison or its habitat at any time.
DATES: The finding announced in this document was made on February 24,
2011.
ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket No. FWS-R6-ES-2010-0095. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Ecological Services, Wyoming Field Office,
5353 Yellowstone Road, Suite 308A, Cheyenne, WY 82009. Please submit
any new information, materials, comments, or questions concerning this
finding to the above address.
FOR FURTHER INFORMATION CONTACT: Mark Sattelberg, Field Supervisor,
Wyoming Field Office (see ADDRESSES), by telephone (307-772-2374) or by
facsimile (307-772-2358). If you use a telecommunications device for
the deaf (TDD), please call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Act (16 U.S.C. 1531 et seq.) requires
that we make a finding on whether a petition to list, delist, or
reclassify a species presents substantial scientific or commercial
information indicating that the petitioned action may be warranted. We
are to base this finding on information provided in the petition,
supporting information submitted with the petition, and information
otherwise available in our files. To the maximum extent practicable, we
are to make this finding within 90 days of our receipt of the petition,
and publish our notice of the finding promptly in the Federal Register.
[[Page 10300]]
Our standard for substantial scientific or commercial information
within the Code of Federal Regulations (CFR) with regard to a 90-day
petition finding is ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted'' (50 CFR 424.14(b)). If we find that substantial
scientific or commercial information was presented, we are required to
promptly conduct a species status review, which we subsequently
summarize in our 12-month finding.
Petition History
On June 22, 2009, we received a petition, dated June 19, 2009, from
James A. Bailey and Natalie A. Bailey, requesting that the wild plains
bison be listed as threatened or that each of its four major ecotypes
be considered DPSs and listed as threatened (Bailey and Bailey 2009,
cover page). The petition clearly identified itself as such and
included the requisite identification information for the petitioners,
as required by 50 CFR 424.14(a). In a July 14, 2009, letter to the
petitioners, we responded that we reviewed the information presented in
the petition and determined that issuing an emergency regulation
temporarily listing the subspecies under section 4(b)(7) of the Act was
not warranted. We also stated that due to staff and budget limitations,
we would not be able to begin work on a 90-day finding for this
petition until Fiscal Year 2010 or 2011. On August 25, 2010, we
received a letter from the petitioners requesting that we consider (1)
New information regarding genetic diversity; (2) a publication by Gates
et al., 2010; (3) the National Park Service's (NPS) draft environmental
impact statement on a proposed brucellosis remote vaccination program;
and (4) any new information that was added to our files since the date
of the original petition. This finding addresses the petition and all
information readily available to us at this time.
Previous Federal Action(s)
We received a petition to list the bison herd at Yellowstone
National Park (Yellowstone) in the northwest corner of Wyoming as a
subspecies or ``distinct population group'' on February 11, 1999. We
completed a 90-day finding on August 15, 2007 (72 FR 45717). Based upon
the information available at that time, we determined that there was
substantial information indicating that the Yellowstone bison herd may
meet the criteria of discreteness and significance as defined by our
policy on DPSs. However, we also determined that there was not
substantial information indicating that listing the Yellowstone bison
herd was warranted throughout all or a significant part of its range,
and a status review was not conducted.
Species Information
Taxonomy
Bison occupied Eurasia about 700,000 years ago and moved across the
Bering Land Bridge into Alaska during the middle Pleistocene Epoch
300,000 to 130,000 years ago (Martin 1970, p. 220; Kurt[eacute]n and
Anderson 1980, p. 39; Gates et al. 2010, p. 5). Bison moved further
south into the grasslands of central North America as ice sheets
retreated 130,000 to 75,000 years ago (Gates et al. 2010, p. 5). The
genus Bison is represented by two extant species, the American bison
(Bison bison) and the European bison (B. bonasus) (Halbert 2003, p. 1;
Gates et al. 2010, p. 15).
Linnaeus first classified the bison in 1758, assigning the animal
to Bos, the same genus as domestic cattle (Bos taurus) (Gates et al.
2010, p. 13). During the 19th century, taxonomists determined that
there was adequate anatomical distinctiveness to warrant assigning the
bison to its own genus, Bison (Gates et al. 2010, p. 13). Since then,
taxonomists have debated the validity of the genus. Some recommend
returning the species to the genus Bos (Boyd 2003, p. 27; Halbert 2003,
p. 2). However, most sources, including the American Society of
Mammalogists, the Integrated Taxonomic Information System (ITIS), and
the International Union for Conservation of Nature (IUCN), consider
Bison as a separate genus from Bos (Meagher 1986, p. 1; Wilson and Ruff
1999, pp. 342-343; Reynolds et al. 2003, p. 1010; Gates et al. 2010, p.
15; ITIS 2010, p. 1). At this time, we support continued placement of
bison in the genus Bison because the majority of taxonomic experts
consider this classification to be correct.
American bison is divided into two subspecies, first recognized by
Rhoads in 1897 (Gates et al. 2010, p. 15). The two subspecies of
American bison, plains bison (B. b. bison) and wood bison (B. b.
athabascae), diverged approximately 5,000 years ago (Halbert 2003, p.
1). Many authors have acknowledged subspecific status, although some
attribute differences in morphology to environmental influences and not
to genetics (Reynolds et al. 2003, p. 1009). Differences in physical
traits between the two subspecies are not affected by geographic
location, suggesting that differences are genetically controlled (Boyd
2003, p. 32; Reynolds et al. 2003, p. 1009; Gates et al. 2010, pp. 15-
18). However, due to the recent divergence of the two bison subspecies,
current genetic analysis techniques may not yet be able to detect the
differences (Boyd 2003, p. 33). At this time, we support continued
recognition of two subspecies of American bison because of geographic
separation, morphological differences, and greater genetic differences
between the two subspecies than within either of the two subspecies
(Gates et al. 2010, pp. 15-18).
Although the two entities are the same species (Bison bison bison),
the petitioners generally limit their discussion to ``wild'' plains
bison and assert that plains bison in commercial herds do not
contribute to restoration of wild plains bison (Bailey and Bailey 2009,
p. 5). Commercial herds are typically managed by private entities for
production of meat and other commodities. Wild plains bison currently
exist only in conservation herds, which are typically managed by
governments and environmental organizations for the purpose of
conserving the subspecies as wildlife in their native ecosystem. The
petitioners contend that commercial herds are selectively bred, mixed
with cattle genes, removed from natural selection, and not legally
classified as wildlife under State laws (Bailey and Bailey 2009, p. 5).
Further, the petitioners claim that wild plains bison in many
conservation herds also may undergo selective culling, contain cattle
genes from early efforts to crossbreed with domestic cattle, are
removed from some aspects of natural selection, and in some cases are
not legally classified as wildlife. These considerations are discussed
in more detail under Factors B, D, and E.
Determination of the Listable Entity
Neither the Act nor our implementing regulations expressly address
whether commercial populations should be considered part of an entity
being evaluated for listing, and no Service policy addresses the issue.
Consequently, in our determination of how to address commercial
populations in our analysis, we considered the following: (1) Our
interpretation of the intent of the Act with respect to the disposition
of native populations, and (2) criteria from another organization
(IUCN) regarding the consideration of commercial populations in species
evaluations.
Intent of the Endangered Species Act
Section 2(b) of the Act states that the purposes of the Act ``are
to provide a means whereby the ecosystems upon which endangered species
and
[[Page 10301]]
threatened species depend may be conserved, to provide a program for
the conservation of such endangered species and threatened species, and
to take such steps as may be appropriate to achieve the purposes of the
treaties and conventions set forth.'' In recent decisions, including a
12-month finding published on September 8, 2010 (75 FR 54707), for the
Arctic grayling (Thymallus arcticus) and a 12-month finding published
on September 22, 2010, for the plant Agave eggersiana (75 FR 57720), we
have focused on wild populations in our analysis of the species' status
and potential threats because these are the populations that contribute
to conservation of the species. Therefore, we believe that considering
populations that contribute to species conservation in a listing
evaluation is consistent with the intent of the Act.
Guidelines Used in Other Evaluation Systems
The IUCN follows similar criteria in their species evaluations. The
IUCN uses its Red List system to evaluate the conservation status and
relative risk of extinction for species, and to catalogue and highlight
plant and animal species that are facing a higher risk of global
extinction (http://www.iucnredlist.org). The IUCN does not use the term
``listable entity'' as the Service does; however, IUCN does clarify
that their conservation ranking criteria apply to any taxonomic group
at the species level or below (IUCN 2001, p. 4). Further, the IUCN
guidelines for species status and scope of the categorization process
focus on wild populations inside their natural range (IUCN 2001, p. 4;
2003, p. 10) or so-called ``benign'' or ``conservation introductions,''
which are defined as attempts to establish a species, for the purpose
of conservation, outside its recorded distribution, when suitable
habitat is lacking within the historical range (IUCN 1998, p. 6; 2003,
pp. 6, 10). Commercial plains bison herds are not eligible for
consideration in the guidelines for evaluating conservation status
under the IUCN (IUCN 2008, http://www.iucnredlist.org). In effect, the
IUCN delineates between commercial plains bison herds and wild plains
bison in conservation herds, in that commercial herds do not qualify
for evaluation under the IUCN Red List system.
There does not appear to be any conservation value for plains bison
in commercial herds, as they are not used in restoration programs.
Instead, their primary purpose is the production of meat and other
commodities for commercial purposes. Our interpretation is that the Act
intended to conserve species in their native ecosystems. We are not
considering plains bison managed for production of meat and other
commodities in this finding because we do not believe that individuals
propagated and managed for commercial uses aid in the conservation or
the recovery of the subspecies in the wild. For the purposes of this
finding, we are analyzing status and potential threats to a petitioned
entity that includes plains bison managed primarily for purposes of
wildlife and ecosystem conservation, hereby referred to as wild plains
bison, even though no bison herd has remained in a completely wild
state since prehistoric times (see our discussion on Significance,
below). Consequently, we do not address commercial bison herds further
in this finding.
In summary, we accept the characterization of plains bison as a
valid subspecies because the preponderance of currently available
information indicates that the genus, species, and subspecies
nomenclature are correct. Furthermore, we will only consider wild
plains bison in conservation herds in this evaluation because we do not
consider it to be within the intent of the Act to consider plains bison
in commercial herds for listing.
Physical Description
Bison are the largest native terrestrial mammal in North America
(Reynolds et al. 2003, p. 1015). Wood bison are generally larger than
the plains bison, but there is an overlap in size and dimensions
between the two subspecies (Meagher 1986, p. 1). Body mass is 1,200 to
2,000 pounds (lbs) (544 to 907 kilograms (kg)) in mature males and 700
to 1,200 lbs (318 to 545 kg) in mature females (Meagher 1986, p. 1).
Bison are brown, with longer hair over the forehead, neck, shoulder
hump, and front-quarters; and shorter hair over the rear and tail
(Meagher 1986, p. 1; Reynolds et al. 2003, p. 1009). The head is large
and carried low on a short, thick neck (Meagher 1986, p. 1; Reynolds et
al. 2003, p. 1009). Both sexes have short, black horns curving upward
and inward, which are never shed (Meagher 1986, p. 1; Reynolds et al.
2003, p. 1009).
Life History
Sexual maturity most commonly occurs at 2 to 4 years of age;
however, bulls do not usually breed until age 6 (Meagher 1986, p. 4).
Female wild plains bison typically breed as 2-year olds and have their
first calf at 3 years (Gates et al. 2010, p. 49). Gestation is
approximately 285 days (Meagher 1986, p. 4). Calving season is from
mid-April through May, with one calf being born; twins are rare
(Meagher 1986, p. 4). Females typically breed until at least 16 years
of age, although they may not breed in every year (Gates et al. 2010,
p. 49).
Wild plains bison are grazers throughout the year, taking mostly
grasses and sedges (Meagher 1986, p. 5; Reynolds et al. 2003, p. 1034).
Most free-ranging wild plains bison appear to be seasonally migratory
(Meagher 1986, p. 5). Females of all ages, calves, and young males form
herds (Meagher 1986, p. 6). Older bulls temporarily join these groups
in late July to mid-August as rut approaches, but are otherwise found
singly or in small groups (Meagher 1986, p. 6; Reynolds et al. 2003, p.
1020). It is likely that the vast historical plains bison herds had a
considerable impact on vegetation within their traditional ranges,
through grazing, nutrient cycling, and physical disturbance (Reynolds
et al. 2003, p. 1037). Prairie dog colonies (Cynomys spp.) are
preferentially grazed by wild plains bison and also are used for
grooming and wallowing (Reynolds et al. 2003, p. 1039).
Distribution
Historically, habitat for the wild plains bison encompassed
approximately 2.8 million square miles (mi2) (7.2 million
square kilometers (km2), with approximately 1.9 million
mi2 (5.0 million km2) west of the Mississippi
River (Sanderson et al. 2008, p. 257). Wild plains bison were most
abundant on the Great Plains, but their range also extended eastward
into the Great Lakes region, beyond the Allegheny Mountains, and into
Florida; westward into Nevada, the Cascade Mountains, and the Rocky
Mountains; northward into mid-Alberta and Saskatchewan; and southward
along the Gulf of Mexico into Mexico (Hornaday 1889, p. 377; Boyd 2003,
p. 20; Reynolds et al. 2003, p. 1012; Gates et al. 2010, p. 56). Wild
plains bison were eliminated west of the Rocky Mountains and east of
the Mississippi River by the early 1800s (Halbert 2003, p. 4). By 1889,
only a few wild plains bison remained in the Texas Panhandle, Colorado,
Wyoming, Montana, and the western Dakotas, as well as a small number in
captive herds (Hornaday 1889, p. 525). Today, wild plains bison occur
in parks, preserves, other public lands, and on private lands
throughout, and external to, their historical range.
[[Page 10302]]
Abundance
Historical estimates regarding numbers of wild plains bison range
from 30 to 75 million (Shaw 1995, p. 149). At the close of the Civil
War, wild plains bison probably numbered in the tens of millions (Shaw
1995, p. 150). Intensive market hunting for hides and meat occurred
following the Civil War; by 1889, a minimum of 285 free-ranging wild
plains bison and 256 captive plains bison were estimated to remain
(Hornaday 1889, p. 525). Recent population estimates range from 400,000
to 500,000, with approximately 20,500 animals in 62 conservation herds
(Gates et al. 2010, p. 57) and the remainder in approximately 6,400
commercial herds (Gates et al. 2010, p. 57).
Trends
In the 1800s, wild plains bison declined from approximately 30
million individuals rangewide to perhaps as few as 541. In the late
1800s, a few concerned individuals undertook independent efforts to
conserve the remaining plains bison (Hornaday 1889, pp. 458-464; Freese
et al. 2007, p. 176). The American Bison Society formed in 1905 and
pressed Congress to establish public bison herds in several locations,
including Wichita Mountains National Wildlife Refuge (NWR) in Oklahoma,
National Bison Range in Montana, Sullys Hill National Game Preserve in
North Dakota, and Fort Niobrara NWR in Nebraska (Boyd 2003, p. 23).
Yellowstone National Park (NP) and Elk Island National Park in Alberta,
Canada, also participated in early efforts to conserve the wild plains
bison. By 1970, an estimated 30,000 plains bison occurred in North
America, approximately half in public conservation herds and half in
private commercial herds (Boyd 2003, p. 23). By 2003, the number of
plains bison in commercial herds increased dramatically to
approximately 300,000 to 500,000 (Boyd 2003, p. 23; Halbert 2003, p.
iii), while wild plains bison in conservation herds increased modestly
to approximately 19,200 (Boyd 2003, p. 23). In 2007, there were
approximately 420,000 plains bison in commercial herds in the United
States and Canada (National Bison Association 2010). In 2008, there
were an estimated 20,500 wild plains bison in conservation herds (Gates
et al. 2010, p. 57). Population trends for wild plains bison in
conservation herds appear stable to slightly increasing in recent
years. The petitioners also note that population trends for wild plains
bison in conservation herds have been stable since the 1930s, based
upon information presented by Freese et al. (2007, p. 177) (Bailey and
Bailey 2009, p. 15).
The most recent information we have in our files regarding
population status and trends of wild plains bison in conservation herds
is presented in the following table. All information is from Boyd
(2003, Appendix 1), with the exception of information for Rocky
Mountain Arsenal NWR (Hastings 2011, pers. comm.) and House Rock Valley
State Wildlife Area (Northern Arizona University 2009, p. 15).
Table 1--Plains Bison Conservation Herd Status
[The Nature Conservancy is abbreviated TNC]
----------------------------------------------------------------------------------------------------------------
Herd Jurisdiction Population Trend
----------------------------------------------------------------------------------------------------------------
Antelope Island State Park, UT......... State..................... 600 Stable.
Badlands NP, SD........................ Federal................... 750 Stable.
Bear River State Park, WY.............. State..................... 8 Stable.
Blue Mounds State Park, MN............. State..................... 56 Stable.
Buffalo Pound Provincial Park, SK...... Provincial (Canada)....... 33 Stable.
Caprock Canyons State Park, TX......... State..................... 40 Decreasing.
Chitina, AK............................ State..................... 38 Stable.
Clymer Meadow Preserve, TX............. TNC & Private............. 320 Stable.
Copper River, AK....................... State..................... 108 Stable.
Cross Ranch Nature Preserve, ND........ TNC....................... 140 Increasing.
Custer State Park, SD.................. State..................... 1100 Stable.
Daniels Park, CO....................... Municipal................. 26 Stable.
Delta Junction, AK..................... State..................... 360 Stable.
Elk Island NP, AB...................... Federal (Canada).......... 430 Stable.
Farewell Lake, AK...................... State..................... 400 Increasing.
Fermi National Accelerator Lab, IL..... Federal................... 32 Stable.
Finney Game Refuge, KS................. State..................... 120 Stable.
Fort Niobrara NWR, NE.................. Federal................... 352 Stable.
Fort Robinson State Park, NE........... State..................... 500 Stable.
Genesee Park, CO....................... Municipal................. 26 Stable.
Grand Teton NP & National Elk Refuge, Federal & State........... 700 Increasing.
WY (Jackson Herd).
Henry Mountains, UT.................... State..................... 279 Stable.
Hot Springs State Park, WY............. State..................... 11 Stable.
House Rock Valley State Wildlife Area, State..................... 276 Increasing.
AZ.
Konza Prairie Biological Station, KS... State & TNC............... 275 Stable.
Land Between the Lakes National Federal................... 130 Decreasing.
Recreation Area, KY.
Maxwell Wildlife Refuge, KS............ State..................... 230 Stable.
Medano-Zapata Ranch, CO................ TNC....................... 1500 Decreasing.
National Bison Range, MT............... Federal................... 400 Stable.
Neal Smith NWR, IA..................... Federal................... 35 Stable.
Niobrara Valley Preserve, NE........... TNC....................... 473 Stable.
Ordway Prairie Preserve, SD............ TNC....................... 255 Stable.
Pink Mountain, BC...................... Provincial (Canada)....... 1000 Stable.
Prairie State Park, MO................. State..................... 76 Stable.
Primrose Air Weapons Range, AB & SK.... Provincial & Federal 100 Increasing.
(Canada).
Prince Albert NP, SK................... Federal (Canada).......... 310 Increasing.
Raymond Wildlife Area, AZ.............. State..................... 72 Stable.
Riding Mountain NP, MB................. Federal (Canada).......... 33 Increasing.
Rocky Mountain Arsenal NWR, CO......... Federal................... 47 Increasing.
[[Page 10303]]
Sandhill Wildlife Area, WI............. State..................... 15 Stable.
Santa Catalina Island, CA.............. Catalina Island 225 Increasing.
Conservancy.
Smoky Valley Ranch, KS................. TNC....................... 45 Increasing.
Sullys Hill National Game Preserve, ND. Federal................... 37 Stable.
Tallgrass Prairie Preserve, OK......... TNC....................... 1500 Increasing.
Theodore Roosevelt NP, ND.............. Federal................... 850 Stable.
Wainwright Training Center, AB......... Federal (Canada).......... 16 Stable.
Waterton Lakes NP, AB.................. Federal (Canada).......... 27 Stable.
Wichita Mountains NWR, OK.............. Federal................... 565 Stable.
Wildcat Hills State Recreation Area, NE State..................... 10 Stable.
Wind Cave NP, SD....................... Federal................... 375 Stable.
Yellowstone NP, WY, MT, ID............. Federal................... 4000 Stable.
----------------------------------------------------------------------------------------------------------------
U.S. Department of the Interior's Bison Conservation Initiative
The U.S. Department of Interior (USDOI) Bison Conservation
Initiative provides a framework for managing wild plains bison within
the USDOI (USDOI 2008, p. 3). This initiative specifies that the USDOI
will: (1) Manage wild plains bison on their lands based on the best
available science, seeking to restore them on appropriate landscapes;
(2) apply adaptive management principles; (3) seek to develop genetic
tests to maximize genetic diversity in herds; (4) seek to develop new
techniques to diagnose, prevent, and control contagious diseases; and
(5) work with interested parties (USDOI 2008, p. 2). One priority of
the Initiative is to actively seek opportunities to increase existing
herds to 1,000 or more wild plains bison, or establish new herds that
can reach that size (USDOI 2008, p. 2). This priority describes numeric
goals and allows the other seven priorities, including genetic
diversity, disease, and introgression with cattle genes, to also be
addressed. This initiative addresses the major concerns of wild plains
bison management on USDOI lands, including genetics, disease,
introgression with cattle genes, and the number and size of herds.
Private Management
Forty-two wild plains bison conservation herds in the United States
were described in 2003; of these, 22 are solely or jointly managed by
States, 12 herds are solely or jointly managed by Federal agencies, 9
herds are solely or jointly managed by private organizations, and 2
herds are managed by municipalities (Boyd 2003, pp. 144-147). An
additional eight herds are managed by Federal or provincial agencies in
Canada (Boyd 2003, p. 147). Since 2003, 12 additional wild plains bison
herds have been enumerated (Gates et al. 2010, p. 57). Initiatives for
new wild herds also are under way, including herds managed by The
Nature Conservancy (TNC) in Alberta and in South Dakota, by American
Prairie Foundation and World Wildlife Fund in Montana, by the Cheyenne
River Sioux Tribe in South Dakota, by the Lower Brule Sioux Tribe in
South Dakota, and by Rosebud Sioux Tribe in South Dakota (Freese et al.
2007, p. 182). Management of wild plains bison for conservation
purposes appears to be active in both the private and public sectors.
An additional 6,400 herds are managed for commercial purposes (Gates et
al. 2010, p. 57).
Evaluation of Information for This Finding
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations at 50 CFR part 424 set forth the procedures for adding a
species to, or removing a species from, the Federal Lists of Endangered
and Threatened Wildlife and Plants. A species may be determined to be
an endangered or threatened species due to one or more of the five
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.
In making this 90-day finding, we evaluated whether information
regarding the threats to the wild plains bison, as presented in the
petition and other information available in our files, is substantial,
thereby indicating that the petitioned action may be warranted. Our
evaluation of this information is presented below.
In considering what factors might constitute threats, we must look
beyond the mere exposure of the species to the factor to determine
whether the species responds to the factor in a way that causes actual
impacts to the species. If there is exposure to a factor, but no
response, or only a positive response, that factor is not a threat. If
there is exposure and the species responds negatively, the factor may
be a threat and we then attempt to determine how significant a threat
it is. If the threat is significant, it may drive or contribute to the
risk of extinction of the species such that the species may warrant
listing as threatened or endangered as those terms are defined by the
Act. This does not necessarily require empirical proof of a threat. The
combination of exposure and some corroborating evidence of how the
species is likely impacted could suffice. The mere identification of
factors that could impact a species negatively may not be sufficient to
compel a finding that listing may be warranted. The information shall
contain evidence sufficient to suggest that these factors may be
operative threats that act on the species to the point that the species
may meet the definition of threatened or endangered under the Act. We
found no information to suggest that threats are acting on the wild
plains bison such that the species may become extinct now or in the
foreseeable future.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
Information Provided in the Petition
The petitioners note the historical destruction and modification of
plains habitat due to conversion to cropland and development of grazing
land for cattle (Bailey and Bailey 2009, p. 15). They assert that there
are ongoing habitat impacts from dam construction, cattle grazing,
cropland conversion, tree invasion, wetland drainage, absence of
[[Page 10304]]
fire, subdivision of land for housing and other construction, and
energy development (Bailey and Bailey 2009, p. 16). They further assert
that with the possible exceptions of cattle grazing and dam
construction, all of these activities are expected to increase in the
foreseeable future (Bailey and Bailey 2009, p. 16). The petitioners
also assert that a lack of populations on a minimum range size of 500
mi\2\ (1,300 km\2\) of habitat threatens the wild plains bison, and
only the Yellowstone herd meets this standard (Bailey and Bailey 2009,
p. 21). The petitioners contend that the lack of suitable habitat is
evidenced by dramatic declines in grassland birds (Bailey and Bailey
2009, p. 22).
Evaluation of Information Provided in the Petition and Available in
Service Files
We agree that there have been historical destruction and
modification of habitat due to conversion to cropland and development
of grazing land for cattle. Information in our files indicates that
cropland conversion, woody plant invasion, and cattle grazing have
altered native grasslands (Ricketts et al. 2008, pp. 273-274), and
cultivation has reduced the tallgrass portion of the Great Plains from
approximately 168 million acres (ac) (68 million hectares (ha)) to less
than 5 percent of that amount (Knapp et al. 1999, p. 39). American
bison, including both plains bison and wood bison in conservation and
commercial herds, currently occupy less than 1 percent of their
historical range (Sanderson et al. 2008, p. 253).
The petitioners do not provide citations to support their
assertions regarding the present or threatened destruction,
modification, or curtailment of habitat or range. Their arguments seem
to rely on the losses of individuals and habitat that occurred in the
1800s. We do not have information indicating that present or potential
future impacts to habitat or range from dam construction, cattle
grazing, cropland conversion, tree invasion, wetland drainage, absence
of fire, subdivision, or energy development are threats to wild plains
bison.
Despite the historical loss of grasslands, much suitable habitat
remains available, and additional habitat has often been only degraded
rather than converted. There is potential for rapid recovery of these
degraded grasslands (Ricketts et al. 2008, p. 288). Boyd (2003, pp. 95,
148-151) states that a lack of suitable habitat is limiting wild plains
bison recovery, but also notes that 25 out of 50 wild plains bison
herds that she evaluated have potential for expansion. The petitioners
note that wild plains bison restoration opportunities exist on public
lands managed by the USDOI and the U.S. Department of Agriculture
(USDA), often mixed with State public lands (Bailey and Bailey 2009, p.
10). National Grasslands managed by the U.S. Forest Service (USFS)
account for nearly 4 million ac (1.6 million ha), with some parcels of
suitable habitat currently large enough to maintain wild plains bison
herds (Olson 1997, p. 4; Ricketts et al. 2008, p. 275). Native American
Tribes also have large tracts of suitable habitat that could support
wild plains bison (Boyd 2003, p. 106; Freese et al. 2007, p. 181).
When determining whether a species should be listed, we examine the
current status of a species, which necessitates examining the species
in its current range and analyzing current and future threats to the
remainder of the species' distribution. The information the petitioner
presented on lost historical range, by itself, does not provide
substantial information that listing the wild plains bison may be
warranted. However, loss of historical range may be relevant to the
analysis of the current and future viability of the species, if the
factors that caused the past decline are shown to be operating on
populations within the current range. Once wild plains bison were
protected from market hunting, beginning in the late 1800s, their
numbers rapidly increased (Gates et al. 2010, p. 9). We do not believe
that the market hunting that led to the precipitous decline of wild
plains bison in the 1800s is likely to be repeated. Habitat is
currently available to accommodate additional herds. Furthermore,
recent stable-to-slightly increasing population trends in conservation
herds do not indicate that habitat is a limiting factor for wild plains
bison.
The petitioners did not provide any citations and we do not have
any information in our files to support a proposed minimum of 500 mi\2\
(1,300 km\2\) of habitat necessary to maintain an ecologically
significant herd. The petitioners state that only the Yellowstone herd
meets this proposed standard, and the Henry Mountain herd nearly meets
it. We are aware of three additional wild plains bison herds that
occupy more than 500 mi\2\ (1,300 km;\2\) of habitat: Farewell Lake in
Alaska, Pink Mountain in British Columbia, and Primrose Air Weapons
Range in Alberta and Saskatchewan. The first two herds are outside of
the historical range of the plains bison, and the Primrose herd is at
the periphery of the historical range. Nevertheless, five herds meet or
exceed 500 mi\2\ (1,300 km\2\). We agree that, in general, the larger
the extent of habitat available, the greater the ecological
significance. However, we believe that herds residing on less than 500
mi\2\ (1,300 km\2\) also can have ecological significance. We have no
evidence that indicates that wild plains bison in herds occupying less
than 500 mi\2\ (1,300 km\2\) of habitat are threatened from lack of
habitat. Most herds, whether occupying more or less than this amount,
exhibit stable to increasing population trends. Therefore, we do not
believe that there is substantial information indicating that listing
may be warranted due to a lack of herds occupying at least 500 mi\2\
(1,300 km\2\) of habitat.
The petitioners also contend that the lack of suitable habitat is
evidenced by dramatic declines in grassland birds (Bailey and Bailey
2009, p. 22). Grassland bird abundance and diversity is one indicator
of a healthy ecosystem, as the petitioners suggest, but addressing
their population trends is beyond the scope of this document. We have
no evidence that there is a relationship between grassland bird
abundance and wild plains bison persistence.
In summary, we find that the information provided in the petition,
as well as other information in our files, does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted due to present or threatened destruction,
modification, or curtailment of habitat or range.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Information Provided in the Petition
The petitioners do not assert that overutilization is a threat to
the wild plains bison. They do note that, historically, wild plains
bison numbered in the tens of millions, but were subsequently reduced
to near extinction (Bailey and Bailey 2009, p. 3). They also suggest
that hunting may be an appropriate management tool (Bailey and Bailey
2009, p. 11).
Evaluation of Information Provided in the Petition and Available in
Service Files
We agree that there was a dramatic historical decline in numbers of
wild plains bison due to market hunting and, to a lesser extent,
subsistence hunting and recreational shooting (Hornaday 1889, pp. 499-
525; Boyd 2003, p. 22; Freese et al. 2007, p. 176; IUCN 2008). However,
market hunting for wild plains bison ended in 1884 (Hornaday
[[Page 10305]]
1889, p. 513) and is no longer a factor. We also agree that hunting can
be an appropriate management tool. Limited authorized hunting of wild
plains bison currently occurs on three public herds in the contiguous
United States, four herds in Alaska, and five herds in Canada (Reynolds
et al. 2003, pp. 1047-1048).
In summary, we find that the information provided in the petition,
as well as other information in our files, does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted due to overutilization for commercial,
recreational, scientific, or educational purposes.
C. Disease or Predation
Information Provided in the Petition
The petitioners note that wild plains bison in the Greater
Yellowstone Ecosystem are infected with brucellosis (Brucella abortus),
which they assert is a minor direct threat, but indirectly severely
limits the herd because of limitations imposed by disease management
(Bailey and Bailey 2009, pp. 8, 21). They note that management for
brucellosis can involve capture, retention, handling, culling, hazing,
and vaccination and assert that this interferes with natural selection,
may enhance disease transmission, alters age structure, and limits herd
numbers (Bailey and Bailey 2009, p. 21). They also contend that
vaccinations in general subvert natural selection and promote
domestication (Bailey and Bailey 2009, p. 21). The petitioners did not
cite predation as a threat.
Evaluation of Information Provided in the Petition and Available in
Service Files
Brucellosis is a bacterial infection that occurs in cattle, bison,
and other mammals (Cook et al. 2004, p. 254; Seabury et al. 2005, p.
104). It has been eradicated from all commercial bison herds and most
wild bison herds in the United States through improved management
(Seabury et al. 2005, p. 105).
Wild plains bison and elk (Cervus elaphus) in the Greater
Yellowstone Area are the last remaining reservoirs of brucellosis in
the United States (Aune et al. 2007, p. 205). Brucellosis is not a
direct threat, because reproduction is only marginally limited, but
wild plains bison can be indirectly affected by the potential risk that
infected bison herds pose to the livestock industry. Wild plains bison
leaving Yellowstone NP in the winter on the northern and western
boundaries are subject to hazing, vaccination, radio-telemetry,
capture, testing, and slaughter of animals that test positive for the
disease (Aune et al. 2007, p. 206). Transmission of brucellosis from
bison to cattle has been demonstrated in captive studies, but there are
no confirmed cases of transmission in the wild (Boyd 2003, p. 80).
In December 2000, following more than 10 years of collaborative
planning, the USDOI (NPS) and the USDA (Animal and Plant Health
Inspection Service and USFS) signed a Record of Decision for a joint
bison management plan for Yellowstone and the State of Montana (USDOI
and USDA 2000, p. 3). The intent of this plan is to preserve
Yellowstone's wild plains bison and minimize the potential risk of
transmission of brucellosis from bison to cattle (USDOI and USDA 2000,
p. 6). This separation is attempted through hazing of wild plains bison
back into Yellowstone, followed by, when necessary, capture, testing,
and slaughter or release of captured bison, depending on test results
(USDOI and USDA 2000, p. 6). Agencies allow wild plains bison outside
of Yellowstone in areas without cattle (USDOI and USDA 2000, p. 11). If
severe winter conditions exist and wild plains bison numbers drop below
2,300, the agencies will temporarily halt slaughter of infected bison
(USDOI and USDA 2000, pp. 13, 34). This plan is a comprehensive
approach to protecting wild plains bison in the Park and minimizing the
risk of brucellosis transmission to cattle grazing on adjacent lands.
The NPS has recently proposed a remote vaccination program for wild
plains bison in Yellowstone that would minimize capture and handling of
bison (NPS 2010, p. iii).
Brucellosis has been eradicated from all wild plains bison herds in
the United States, with the exception of the two herds in the Greater
Yellowstone Area (Yellowstone and Jackson herds). The Jackson herd is
jointly managed by Grand Teton National Park and the Service's National
Elk Refuge. Disease management is ongoing in these two herds. The
petitioners contend that the hazing, capture, vaccination, and culling
that may occur subvert natural selection, may enhance disease
transmission, alter age structure, and limit herd numbers (Bailey and
Bailey 2009, p. 21). However, the petitioners did not provide evidence
to support that these activities are a threat to the status of the
species such that the species may warrant listing as threatened or
endangered. Furthermore, recent stable-to-increasing population trends
do not indicate that management for brucellosis is a limiting factor
for wild plains bison in the Greater Yellowstone Area. Additionally,
disease management is often an essential aspect of wildlife management.
In summary, we find that the information provided in the petition,
as well as other information in our files, does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted due to disease or predation.
D. The Inadequacy of Existing Regulatory Mechanisms
Information Provided in the Petition
The petitioners assert that existing Federal and State regulatory
mechanisms for wild plains bison conservation are inadequate (Bailey
and Bailey 2009, pp. 16-19). They cite the Interagency Bison Management
Plan for Yellowstone NP, the USDOI's Bison Conservation Initiative,
Charles M. Russell NWR, National Grasslands management, and legal
designations by the States as examples of inadequate regulations where
more could be done to restore wild plains bison. They also assert that
management by private programs is inadequate (Bailey and Bailey 2009,
p. 19).
Evaluation of Information Provided in the Petition and Available in
Service Files
We consider plans and initiatives to be voluntary agreements that
provide guidance for better managing wild plains bison, rather than
regulatory mechanisms. Therefore, we discuss the Interagency Bison
Management Plan for Yellowstone under Factor C, because it focuses on
disease. The USDOI's Bison Conservation Initiative and private programs
are discussed under Background. Management of wild plains bison on NWRs
and National Grasslands, and legal designations by States, are
discussed under this factor. We evaluate the inadequacy of existing
regulatory mechanisms from the standpoint of the other factors. If
there is not substantial information that listing a species may be
warranted due to another factor, then the regulations affecting that
factor cannot be considered inadequate.
Charles M. Russell National Wildlife Refuge
The National Wildlife Refuge System Administration Act established
the National Wildlife Refuge System and identified a primary mission of
wildlife conservation. The Service manages over 500 National Wildlife
Refuges and their satellites. Wild plains bison
[[Page 10306]]
conservation is a National Wildlife Refuge System priority (Jones and
Roffe 2008, p. 5). Purposes of wild plains bison management include:
(1) To fulfill a legal mandate as part of establishing a Refuge, (2) to
conserve bison, (3) to provide education and recreation for the public,
(4) to manage habitat, (5) to protect cultural or historic
significance, and (6) to carry out research (Jones and Roffe 2008, p.
5). Charles M. Russell NWR is one of eight National Wildlife Refuges in
the contiguous United States that include wild plains bison management
among their priorities (Jones and Roffe 2008, p. 3). Wild plains bison
management is at an early stage at Charles M. Russell NWR, with only a
small number of bison currently present. The other refuges with wild
plains bison are Wichita Mountains NWR in Oklahoma (herd founding date
1907), the National Bison Range in Montana (herd founding date 1908),
Fort Niobrara NWR in Nebraska (two herds, founding dates 1913 and
1919), Sullys Hill National Game Preserve in North Dakota (herd
founding date 2006), Neal Smith NWR in Iowa (herd founding date 1996),
the National Elk Refuge in Wyoming (jointly managed with Grand Teton
National Park; herd founding date 1948), and Rocky Mountain Arsenal NWR
in Colorado (herd founding date 2007). The Service has a strong and
active commitment to wild plains bison conservation and ecological
restoration, and we do not believe that there is substantial
information indicating that listing may be warranted due to perceived
inadequacies in refuge planning at Charles M. Russell NWR.
National Grasslands Management
The USFS administers 20 National Grasslands consisting of
approximately 3.8 million ac (1.6 million ha) in 13 States, but the
grasslands are primarily in Colorado, North Dakota, South Dakota, and
Wyoming (Olson 1997, p. 4). According to the Federal Land Policy and
Management Act, these grasslands are to be administered under sound and
progressive principles of land conservation and multiple use (36 CFR
part 213). Approximately 189 million ac (77 million ha) of National
Forests also are managed by the USFS. We believe that several National
Grasslands and National Forests are of sufficient size and habitat type
to support wild plains bison. Wild plains bison on USFS lands are
typically the result of overflow from herds on NPS lands (such as the
Yellowstone herd) (USDOI and USDA 2000, p. 3), or are State-owned herds
(such as the House Rock Valley herd) (Northern Arizona University 2009,
p. 1). These wild plains bison are adequately protected by Federal laws
and regulations mandating how USFS lands are managed. We do not believe
that there is substantial information indicating that listing may be
warranted due to lack of actions on the part of the USFS.
Legal Designations
Plains bison fall into an unusual legal classification that can
complicate understanding the management intent for a given herd (Freese
et al. 2007, p. 181). Their legal status can be either domestic
livestock or wildlife among various Federal, State, and provincial
jurisdictions across North America (Gates et al. 2010, p. 66). Plains
bison are managed as captive or free-ranging wildlife on National Parks
and National Wildlife Refuges. They have dual status (herds may be
considered domestic livestock or wildlife, depending on whether they
are commercial or conservation herds) in Alaska; Arizona; Idaho; Utah;
Missouri; Montana; New Mexico; South Dakota; Texas; Wyoming; British
Columbia; Saskatchewan; and Chihuahua, Mexico (Gates et al. 2010, pp.
66-73). Plains bison are classified solely as domestic livestock in
Colorado, Illinois, Iowa, Kansas, Louisiana, Minnesota, Nebraska, North
Dakota, Nevada, Oklahoma, Alberta, and Manitoba, regardless of whether
they are in commercial or conservation herds (Gates et al. 2010, pp.
66-73). Nevertheless, wild plains bison that are classified as domestic
livestock and are in conservation herds are managed for purposes of
wildlife conservation, and not for production of meat and other
commodities. Therefore, they are not adversely affected by their legal
designation. A more uniform and straightforward classification of
plains bison could simplify the regulatory status by which they are
managed, but we do not believe that there is substantial information
indicating that listing may be warranted due to their legal status.
Summary of Factor D
In summary, we find that the information provided in the petition,
as well as other information in our files, does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted due to the inadequacy of existing regulatory
mechanisms.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Information Provided in the Petition
The petitioners assert that loss of genetic diversity threatens the
wild plains bison, and that a minimum herd size of 2,000 animals is
required to provide genetic diversity, noting that only 1 herd
(Yellowstone) fulfills this requirement (Bailey and Bailey 2009, p.
19). They contend that management activities such as roundups, culling,
protection from predators, pasture rotation, supplemental feeding, and
vaccination lead toward domestication and genomic extinction (Bailey
and Bailey 2009, p. 20).
The petitioners assert that introgression (hybridization) with
cattle genes threatens the wild plains bison, and that only seven herds
have been found to be free of cattle genes (Bailey and Bailey 2009, p.
20). The petitioners also allude to impacts from climate change, noting
that the presence of at least one wild plains bison herd in each of the
four major ecotypes could provide redundancy, resiliency, and perhaps
genetic adaptations in the event of global warming (Bailey and Bailey
2009, pp. 11-12).
Evaluation of Information Provided in the Petition and Available in
Service Files
Loss of Genetic Diversity
Preservation of genetic diversity in the wild plains bison is
essential to its conservation (Boyd 2003, p. 60). Genetic diversity
provides flexibility for evolutionary change and adaptation (Gardipee
2007, p. 1; Gates et al. 2010, p. 19). The population decline for wild
plains bison was severe--from tens of millions to possibly as low as
541 animals. Demographic bottlenecks such as this, and resultant
founder effects, genetic drift, and inbreeding, can reduce genetic
diversity (Boyd 2003, p. 60). The consequences of a bottleneck depend
on the severity of the decline and how quickly the population recovers
(Boyd 2003, p. 60).
The small numbers of plains bison remaining after the bottleneck
resulted in very few founders and the possibility for genetic drift,
which involves the random change in gene frequencies leading to the
loss of certain unique DNA sequences in a particular gene type (allele)
from one generation to the next (Boyd 2003, pp. 60-61). Small
populations also may experience inbreeding or highly skewed gender
ratios, which can lead to the expression of deleterious alleles, the
decreased presence of both dominant and
[[Page 10307]]
recessive alleles (decreased heterozygosity (decreased hybridization of
genes; an indicator of poor genetic health), lower fecundity, and
developmental defects (Boyd 2003, p. 61). However, the duration of the
bottleneck for plains bison was relatively short (Halbert 2003, p. 52),
and the population recovered quickly (Boyd 2003, p. 60). Pre-bottleneck
wild plains bison numbers, movement, and distribution suggest
widespread interbreeding and significant genetic homogeneity among
continental populations. The selection of captive and wild plains bison
used in early foundation herds represented a large portion of the
historical range and, therefore, likely captured a large portion of
pre-bottleneck genetic variation (Halbert 2003, p. 52). Today's wild
plains bison have substantially greater genetic variation than reported
for other mammalian species that have experienced similar bottlenecks
(Halbert 2003, p. 51). In general, populations of wild plains bison
that have been tested display a moderately high level of overall
genetic diversity, with notable differences in overall allelic
variation and heterozygosity (Halbert 2003, p. 60).
A minimum viable population (MVP) is the smallest population size
that provides a high probability (typically 95 percent) of persistence
for a given period of time (typically, 100 years) (Boyd 2003, p. 36).
Large-bodied species with a long lifespan tend to experience less
severe population fluctuations than smaller, short-lived species (Boyd
2003, p. 37). Consequently, a lower MVP is typical for large, long-
lived species. The Canadian National Wood Bison Recovery Team uses a
MVP of 400 for wood bison (Boyd 2003, p. 38). More recently, the IUCN
considered wild plains bison populations to be viable if they were
greater than 1,000 animals (IUCN 2008). Freese et al. (2007, p. 180)
suggest that in consideration of exotic diseases and climate change, a
prudent goal would be retention of at least 95-percent allelic
diversity for 200 years, which would require a MVP of 2,000 animals. We
are aware of 15 conservation herds with at least 400 wild plains bison,
4 conservation herds with at least 1,000 wild plains bison (Custer
State Park in South Dakota, Medano-Zapata Ranch in Colorado, Pink
Mountain in British Colombia, and Yellowstone), and 1 conservation herd
with more than 2,000 wild plains bison (Yellowstone). Selectively
moving animals in smaller herds from one herd to another as is still
frequently done in conservation herds, and can counter the effects of
genetic drift and maintain viability (Halbert 2003, p. 153; Jones and
Roffe 2008, p. 8). The USDOI has a priority of increasing their
existing herds to at least 1,000 animals, or establishing new herds
that can reach that size (USDOI 2008, p. 2).
All wild plains bison herds have experienced some degree of
management, ranging from initial establishment of the herd to more
intensive management activities such as roundups, culling, protection
from predators, pasture rotation, supplemental feeding, and
vaccination. We recognize that maximizing the wildness of the plains
bison is important for the maintenance of genetic diversity, but also
believe that continued judicious management is necessary for long-term
survival in the modern world. For example, in an effort to minimize
capture and handling of wild plains bison in Yellowstone, the NPS is
considering the use of air rifles to deliver brucellosis vaccines
remotely (NPS 2010, p. iii).
Populations of wild plains bison that have been tested display a
moderately high level of overall genetic diversity. Selective movement
of animals between herds, as currently practiced, can help maintain
that genetic diversity. We do not believe that there is substantial
information indicating that listing may be warranted due to a loss of
genetic diversity.
Introgression With Cattle Genes
Introgression was caused by hybridization between plains bison and
cattle, followed by breeding of the hybrid offspring to at least one of
their respective parental populations (Gates et al. 2010, p. 22). The
introgressed or alien DNA replaced sections of the original DNA,
thereby affecting the genetic integrity of the wild plains bison (Gates
et al. 2010, p. 22). Most genetic studies we are aware of have been
conducted on conservation herds (Polziehn et al. 1995, p. 1638; Ward et
al. 1999, p. 52; Boyd 2003, p. 68; Halbert 2003, p. 70; Halbert et al.
2005, pp. 2349-2350).
When plains bison were at their lowest numbers in the late 1800s, a
few individuals established small captive foundation herds that saved
the subspecies from extinction. Each of these herds was, to some
extent, used to either experimentally create bison-domestic cattle
crosses, or supplemented with plains bison from herds involved in such
experiments (Halbert et al. 2005, p. 2344). Controlled breeding of male
plains bison to female domestic cattle has been recorded extensively,
although the birth rate of first-generation offspring is very low
(Halbert et al. 2005, p. 2344), and male offspring are usually sterile
(Meagher 1986, p. 6). Behavioral constraints typically prevent domestic
bulls from mating with female bison (Boyd 2003, p. 67). Due to the
sterility of male offspring and the lack of domestic bulls that
successfully breed with female bison, there is no evidence of male-
linked or Y-chromosome cattle gene introgression in bison (Boyd 2003,
p. 67). However, maternally inherited DNA, known as mitochondrial DNA
(mtDNA), and nuclear DNA (contributed by either parent) introgression
have been demonstrated (Polziehn et al. 1995, p. 1641; Ward et al.
1999, p. 51; Boyd 2003, p. 67; Halbert 2003, p. 13), which indicates
that many plains bison contain some cattle DNA from experimental
crosses conducted in the past.
The proportion of cattle DNA that has been measured in introgressed
individuals and herds is typically quite low, ranging from 0.56 to 1.8
percent (Polziehn et al. 1995, p. 1642; Halbert et al. 2005, p. 2343).
However, estimates based on extrapolation from portions of genomes
sampled, to the entire genome, to all animals in a herd should be
considered only as approximations (Roffe and Jones 2008, p. 1). The
petitioners assert that seven herds have been found free of cattle
genes (Bailey and Bailey 2009, p. 20). We are aware that very few herds
lack evidence of at least some cattle allele introgression. Based upon
the information currently available, the following wild plains bison
conservation herds show no evidence of introgression: Elk Island
National Park in Alberta, Jackson herd (Grand Teton National Park--
National Elk Refuge) in Wyoming, Henry Mountains in Utah, Sullys Hill
National Game Preserve in North Dakota, Wind Cave National Park in
South Dakota, and Yellowstone (Halbert and Derr 2007, p. 8). One
private herd, Castle Rock in New Mexico, also shows no evidence of
introgression (Freese et al. 2007, p. 182). The Jackson and Sullys Hill
herds have not been adequately sampled to allow for statistical
confidence (Halbert and Derr 2007, p. 8), and many other herds have not
yet been tested. As techniques improve and more extensive sampling
occur, some herds previously without evidence of introgression may be
found to contain introgressed alleles.
Some conservation herds known to have low levels of cattle
introgression also contain unique or rare plains bison genetic
diversity (Halbert 2003, p. 98; Gates et al. 2010, p. 23). To minimize
genetic loss and not exacerbate the effects of the historical
bottleneck on the wild plains bison, managers feel that
[[Page 10308]]
this unique genetic background should be conserved, while herds with no
evidence of introgression should be maintained in isolation from
introgressed populations (Halbert 2003, p. 94). Issues of introgression
and unique genetic diversity are both considered in management of wild
plains bison.
The presence of cattle DNA in the genetic makeup of wild plains
bison appears widespread, but occurs at low levels. Conservation herds
are managed according to their genetic background, so as to maintain
genetic diversity and introgression-free herds. We expect the frequency
of cattle DNA to remain low in conservation herds. Wild plains bison
from introgressed herds conform morphologically, behaviorally, and
ecologically to the scientific taxonomic description of the native
subspecies. Some wild plains bison herds with evidence of cattle
introgression also contain valuable genetic diversity that is not found
elsewhere and should be conserved. We do not believe that there is
substantial information indicating that listing may be warranted due to
introgression with cattle genes.
Climate Change
No information on the direct relationship between climate change
and wild plains bison was provided by the petitioners or is available
in our files. According to the Intergovernmental Panel on Climate
Change (IPCC 2007, p. 6), ``warming of the climate system is
unequivocal, as is now evident from observations of increases in global
average air and ocean temperatures, widespread melting of snow and ice,
and rising global average sea level.'' Average Northern Hemisphere
temperatures during the second half of the 20th century were very
likely higher than during any other 50-year period in the last 500
years, and likely the highest in at least the past 1,300 years (IPCC
2007, p. 6). It is very likely that over the past 50 years, cold days,
cold nights, and frosts have become less frequent over most land areas,
and hot days and hot nights have become more frequent (IPCC 2007, p.
6). It is likely that heat waves have become more frequent over most
land areas, and the frequency of heavy precipitation events has
increased over most areas (IPCC 2007, p. 6).
Changes in the global climate system during the 21st Century are
likely to be larger than those observed during the 20th Century (IPCC
2007, p. 19). For the next 2 decades, a warming of about 0.2
[deg]Celsius ([deg]C) (0.4 [deg]Fahrenheit ([deg]F)) per decade is
projected (IPCC 2007, p. 19). Afterward, temperature projections
increasingly depend on specific emissions scenarios (IPCC 2007, p. 19).
Various emissions scenarios suggest that by the end of the 21st
Century, average global temperatures are expected to increase 0.6 to
4.0 [deg]C (1.1 to 7.2 [deg]F), with the greatest warming expected over
land (IPCC 2007, p. 20). The IPCC (2007, pp. 22, 27) report outlines
several scenarios that are virtually certain or very likely to occur in
the 21st Century including: (1) Over most land, there will be warmer
days and nights, and fewer cold days and nights, along with more
frequent hot days and nights; (2) areas affected by drought will
increase; and (3) the frequency of warm spells and heat waves over most
land areas will likely increase. The IPCC predicts that the resiliency
of many ecosystems is likely to be exceeded this century by an
unprecedented combination of climate change, associated disturbances
(e.g., flooding, drought, wildfire, and insects), and other global
drivers. With medium confidence, IPCC predicts that approximately 20 to
30 percent of plant and animal species assessed so far are likely to be
at an increased risk of extinction if increases in global average
temperature exceed 1.5 to 2.5 [deg]C (3 to 5 [deg]F).
The wild plains bison had a very extensive historical range that
extended nearly coast to coast and from central Canada to northern
Mexico. Therefore, it would appear that it is adaptable to a wide
variety of climatic conditions. We also believe that all four ecotypes
described by the petitioners as potential distinct population segments
will persist in the face of climate change. Consequently, we do not
believe that there is substantial information indicating that listing
may be warranted due to climate change.
Summary of Factor E
In summary, we find that the information provided in the petition,
as well as other information in our files, does not present substantial
scientific or commercial information indicating that the petitioned
action may be warranted due to loss of genetic diversity, introgression
with cattle genes, or climate change.
Summary of Five Factor Evaluation
We have carefully examined information from the petition and from
our files regarding the status of wild plains bison. We also consulted
with Service biologists and managers from NWRs that have wild plains
bison. There have been several impacts to the wild plains bison; in
particular, market hunting caused a precipitous decline in the mid- to
late-1800s. Diligent efforts by a few individuals prevented extinction.
However, subsequent attempts to crossbreed plains bison with cattle
resulted in low-level, but widespread, presence of cattle DNA.
Nevertheless, the wild plains bison appears to have retained much of
its genetic diversity. However, the presence of both commercial herds
and conservation herds has resulted in some conflicting legal
designations. Brucellosis in the Greater Yellowstone Ecosystem requires
special management. Despite these stressors, the numbers of plains
bison have increased dramatically since the early 1900s, and population
trends of wild plains bison in conservation herds appear to be stable
to increasing in recent years. The number of conservation herds also
continues to increase. In summary, the petition does not present
substantial information that wild plains bison as a subspecies may
require listing.
Distinct Vertebrate Population Segments
The petitioners requested that if we should determine that
substantial information was not presented indicating that listing may
be warranted, then each major ecotype of the subspecies should be
listed as a ``significant distinct population segment (DPS).'' The
petitioners specified four ecotypes (population segments) of wild
plains bison: The northern Great Plains, the southern Great Plains, the
Rocky Mountains, and the Great Basin-Colorado Plateau.
To interpret and implement the DPS provisions of the Act, the
Service and the National Oceanic and Atmospheric Administration
published the Policy Regarding the Recognition of Distinct Vertebrate
Population Segments Under the Endangered Species Act in the Federal
Register on February 7, 1996 (61 FR 4722). Under the DPS Policy, three
elements are considered in the decision regarding the establishment and
classification of a population of a vertebrate species as a possible
DPS: (1) The discreteness of a population in relation to the remainder
of the species to which it belongs, (2) the significance of the
population segment to the species to which it belongs, and (3) the
population segment's conservation status in relation to the Act's
standards for listing, delisting, or reclassification. Both
discreteness and significance are required for a species population to
meet our criteria for classification as a DPS. If any portion of a
species' population is considered a potentially valid DPS, we may list,
delist, or reclassify that DPS under the Act. We
[[Page 10309]]
address these elements with respect to the wild plains bison.
Discreteness
Under the DPS policy, a population segment of a vertebrate species
may be considered discrete if it satisfies either one of the following
conditions: (1) It is markedly separated from other populations of the
same taxon as a consequence of physical, physiological, ecological, or
behavioral factors (quantitative measures of genetic or morphological
discontinuity may provide evidence of this separation); or (2) it is
delimited by international governmental boundaries within which
differences in control of exploitation, management of habitat,
conservation status, or regulatory mechanisms exist that are
significant in light of section 4(a)(1)(D) of the Act.
Markedly Separated
The petitioners assert that the four proposed wild plains bison
ecotypes or population segments are physically separated, and therefore
discrete (Bailey and Bailey 2009, p. 11). While nearly all conservation
herds are geographically separated, the available information indicates
that the ``markedly separated'' criteria are not satisfied because the
frequent interchange between herds that has occurred since the late
1800s has provided a physical connectivity between herds, and has
maintained genetic homogeneity.
There is no evidence indicating that landscape features
historically separated herds of plains bison. Prior to the population
bottleneck in the late 1800s, the species likely experienced a high
degree of genetic homogeneity, despite their extensive range (Gates et
al. 2010, p. 20). Wild plains bison ranged over large areas, suggesting
extensive animal movement and gene flow between populations (Gates et
al. 2010, p. 20).
Separation should also be considered in the context of the more
recent history of the four wild plains bison ecotypes or population
segments. Several researchers have concluded that nearly all plains
bison present today in both commercial and conservation herds descend
from 76 to 84 individuals from 5 private foundation herds and no more
than 30 wild bison in Yellowstone (Halbert 2003, p. 9). The private
foundation herds originated from across a large portion of the species'
range. Early federally owned herds were established from foundation
herds and subsequently augmented with plains bison from multiple herds
in disparate locations. For example, the current wild plains bison herd
on the National Bison Range was started in 1908 with stock from three
different foundation herds in Canada, Texas, and Montana (Halbert and
Derr 2007, p. 2). This same herd was augmented in 1939 with plains
bison from a private ranch of unknown origin; in 1952 with wild plains
bison from Fort Niobrara NWR, Nebraska; in 1953 with wild plains bison
from Yellowstone, Wyoming; and in 1984 with wild plains bison from
Maxwell Wildlife Refuge, Kansas (Halbert and Derr 2007, p. 2). Similar
histories exist for most other Federal herds (Halbert and Derr 2007, p.
2). In contrast, one State-owned herd, the Texas Caprock herd, has been
a small, closed population for more than 120 years since its founding
with five plains bison from the Goodnight foundation herd (Halbert
2003, p. 95). This herd suffers from lower birth rates and higher death
rates than other captive herds (Halbert 2003, p. 95). The careful
introduction of unrelated plains bison has been recommended to increase
genetic diversity, reduce inbreeding, and increase fitness (Halbert
2003, p. 124).
The strategy for wild plains bison herds in the National Wildlife
Refuge System is to manage bison as a metapopulation to maintain the
genetic complement and minimize loss of diversity through low levels of
carefully planned and monitored translocations between herds (Jones and
Roffe 2008, p. 9). Similar translocations occur for other public herds
(Halbert and Derr 2007, p. 2). Translocations are often between
ecotypes, which further supports management as a metapopulation (Boyd
2003, Appendix 2).
The diverse origins of the early foundation herds, and subsequent
translocations that were undertaken (and continue to be undertaken) to
establish new herds and to later augment herds, have resulted in
population segments that, despite their current geographic separation,
are essentially one metapopulation where connectivity is maintained
through management practices. Therefore, the four wild plains bison
ecotypes or population segments are not markedly separate.
International Boundaries With Differences in Exploitation, Management,
Status, or Regulations
Although wild plains bison herds also occur in Canada, each of the
four plains bison ecotypes or population segments proposed by the
petitioners occurs within the United States. Therefore, there are no
international governmental boundaries to consider.
Conclusion
The historically wide-ranging nature of wild plains bison likely
resulted in a high degree of genetic homogeneity for the species. The
subsequent management of the wild plains bison has maintained that
homogeneity through numerous translocations between various
conservation herds. Additionally, there are no international boundaries
between the four proposed population segments. Therefore, the
discreteness criteria, as applied to the DPS policy, have not been met.
Significance
Because the petition does not present substantial information that
any of the four wild plains bison ecotypes or population segments is
discrete, we did not evaluate whether the information contained in the
petition regarding significance was substantial. However, we note that
the wild plains bison is a generalist with regard to its habitat
requirements, as evidenced by its broad historical range, and none of
the ecological settings of the four population segments is unique or
unusual. Each of the population segments contains multiple herds
managed under different Federal, State, municipal, or private regimes,
and the complete loss of any population segment is very unlikely. No
population segment represents the only surviving natural occurrence of
the taxon. Lastly, due to multiple, diverse origins and subsequent
translocations, no population segment is genetically, behaviorally, or
ecologically unique.
We recognize that this conclusion differs to some extent from an
earlier decision. In a previous negative 90-day finding published on
August 15, 2007 (72 FR 45717), we determined that the Yellowstone
plains bison herd may meet the criteria of discreteness and
significance as defined by our policy on DPS. However, this finding and
the previous 90-day finding differ in scope. The August 15, 2007,
finding only addressed plains bison in the Yellowstone herd. The
current finding addresses wild plains bison in all conservation herds.
The 2007 finding concluded that the Yellowstone herd may be
discrete from other plains bison, because it was considered the only
herd that has ``remained in a wild state since prehistoric times'' and
because of physical distance and barriers. The best available
information now indicates that the basis for our 2007 DPS determination
was erroneous. We still use the term ``wild plains bison'' to describe
the Yellowstone herd because
[[Page 10310]]
they are managed as a conservation herd, rather than as a commercial
herd. However, we no longer consider the Yellowstone herd to have
remained in more of a ``wild'' state than any other conservation herd.
Specifically, these wild plains bison are no longer thought to have
remained in an unaltered condition from prehistoric times, as implied
in the previous determination. In 1902, no more than 30 wild plains
bison remained in Yellowstone (Halbert 2003, p. 24). In the same year,
18 female plains bison from the captive Pablo-Allard herd in Montana
and 3 bulls from the captive Goodnight herd in Texas were purchased to
supplement the Yellowstone herd (Halbert 2003, pp. 24-25).
Additionally, intensive management (supplemental feeding, roundups, and
selective culling) of the Yellowstone herd occurred from the 1920s
through the late 1960s (Gogan et al. 2005, p. 1719). Wild plains bison
from Yellowstone also have been used to start or augment many later
conservation herds (Halbert and Derr 2007, p. 2). Despite geographic
separation, the Yellowstone herd is essentially part of one
metapopulation and is not markedly separate from other herds.
Summary of the Distinct Population Segment Analysis
On the basis of the preceding discussion, we believe that the
petition has not provided substantial information to conclude that each
of the four population segments may be discrete. Therefore, we did not
evaluate significance or conservation status of the four population
segments within the meaning of the DPS Policy. In conclusion, we do not
believe that any of the population segments may constitute a valid DPS.
However, even if we had concluded that the four population segments
may be discrete and significant, the petition does not present
substantial information that any of the stressors described under the
above five factor analysis are concentrated within any one DPS to
indicate that any of the DPSs would be more likely to be threatened or
endangered than the species at large. Thus, there is no information
indicating stressors rise to the level of a threat for any population
segment.
Finding
In summary, the petition does not present substantial information
that wild plains bison may require listing either as a subspecies or a
DPS. The conclusion that impacts from the various factors discussed
above may constitute a threat is not supported by the available
information regarding distribution, abundance, and population trends of
wild plains bison. Wild plains bison are distributed in parks,
preserves, other public lands, and private lands throughout and
external to their historical range. The current population of wild
plains bison is estimated to be 20,500 animals in 62 conservation
herds. Recent population trends appear stable to slightly increasing in
conservation herds (as noted by the petitioners).
On the basis of our determination under section 4(b)(3)(A) of the
Act, we conclude that the petition does not present substantial
scientific or commercial information to indicate that listing the wild
plains bison, or any of four proposed DPSs, under the Act as threatened
or endangered may be warranted at this time. Although we will not
review the status of the species at this time, we encourage interested
parties to continue to gather data that will assist with conservation
of the wild plains bison. If you wish to provide information regarding
the wild plains bison, you may submit your information or materials to
the Wyoming Field Supervisor (see ADDRESSES) at any time.
References Cited
A complete list of references cited is available on the Internet at
http://www.regulations.gov and upon request from the Wyoming Field
Office (see FOR FURTHER INFORMATION CONTACT).
Authors
The primary authors of this notice are staff members of the
Mountain-Prairie Regional Office and the Wyoming Field Office (see
ADDRESSES).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Rowan W. Gould,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2011-4121 Filed 2-23-11; 8:45 am]
BILLING CODE 4310-55-P