# Endangered and Threatened Wildlife and Plants; Lesser Prairie-Chicken; Threatened Status With Section 4(d) Rule for the Northern Distinct Population Segment and Endangered Status for the Southern Distinct Population Segment

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2022-25214

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** November 25, 2022
- **Citation:** 87 FR 72674

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R2-ES-2021-0015; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BB27
Endangered and Threatened Wildlife and Plants; Lesser Prairie-Chicken; Threatened Status With Section 4(d) Rule for the Northern Distinct Population Segment and Endangered Status for the Southern Distinct Population Segment

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), are listing two Distinct Population Segments (DPSs) under the Endangered Species Act of 1973 (Act), as amended, for the lesser prairie-chicken (
Tympanuchus pallidicinctus
), a grassland bird known from southeastern Colorado, western Kansas, eastern New Mexico, western Oklahoma, and the Texas Panhandle. We determine threatened status for the Northern DPS and endangered status for the Southern DPS. This rule adds the DPSs to the List of Endangered and Threatened Wildlife. We also finalize a rule under the authority of section 4(d) of the Act that provides measures that are necessary and advisable to provide for the conservation of the Northern DPS.

DATES:

This rule is effective January 24, 2023.

ADDRESSES:

This final rule is available on the internet at
https://www.regulations.gov.
Comments and materials we received, as well as supporting documentation we used in preparing this rule, are available for public inspection at
https://www.regulations.gov at
Docket No. FWS-R2-ES-2021-0015.

FOR FURTHER INFORMATION CONTACT:

Beth Forbus, Regional ES Program Manager, Southwest Regional Office, 500 Gold Ave SW, Albuquerque, NM 87102; telephone 505-318-8972. Individuals in the United States who are deaf, deafblind, hard of hearing, or have a speech disability may dial 711 (TTY, TDD, or TeleBraille) to access telecommunications relay services. Individuals outside the United States should use the relay services offered within their country to make international calls to the point-of-contact in the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule.
Under the Act, a species warrants listing if it meets the definition of an endangered species (in danger of extinction throughout all or a significant portion of its range) or a threatened species (likely to become endangered in the foreseeable future throughout all or a significant portion of its range). If we determine that a species warrants listing, we must list the species promptly and designate the species' critical habitat to the maximum extent prudent and determinable. We have determined that the Northern DPS of the lesser prairie-chicken meets the definition of a threatened species and that the Southern DPS of the lesser prairie-chicken meets the definition of an endangered species; therefore, we are listing them as such and finalizing a rule under section 4(d) of the Act for the Northern DPS. Listing a species as an endangered or threatened species can be completed only by issuing a rule through the Administrative Procedure Act's rulemaking process.

What this document does.
This rule revises the regulations in title 50 of the Code of Federal Regulations to list the Northern DPS of the lesser prairie-chicken as a threatened species with a rule under section 4(d) of the Act and the Southern DPS of the lesser prairie-chicken as an endangered species under the Act.

The basis for our action.
Under the Act, we may determine that a species is an endangered or threatened species because of any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that both the northern and southern parts of the lesser prairie-chicken's range are discrete and significant under our DPS Policy and are, therefore, listable entities under the Act. The Southern DPS includes the Shinnery Oak Ecoregion in New Mexico and Texas, and the Northern DPS includes the Sand Sagebrush Ecoregion, the Mixed-Grass Ecoregion, and the Short-Grass/Conservation Reserve Program (CRP) Ecoregion in Texas, Oklahoma, Colorado, and Kansas. These two DPSs together encompass the entirety of the lesser prairie-chicken's range. The primary threat impacting both DPSs is the ongoing loss of large, connected blocks of grassland and shrubland habitat. The Southern DPS has low resiliency, redundancy, and representation and is particularly vulnerable to severe droughts due to being located in the dryer and hotter southwestern portion of the range. Because the Southern DPS is currently at risk of extinction, we are listing it as endangered.

In the Northern DPS, as a result of habitat loss and fragmentation, resiliency has been much reduced across two of the ecoregions in the Northern DPS when compared to historical conditions. However, this DPS still has redundancy across the three ecoregions and genetic and environmental representation. We expect habitat loss and fragmentation across the Northern DPS to continue into the foreseeable future, resulting in even further reduced resiliency. Because the Northern DPS is at risk of extinction in the foreseeable future, we are listing it as threatened. The section 4(d) rule for the Northern DPS of the lesser prairie-chicken generally prohibits the same activities as prohibited for an endangered species. It includes exceptions from take associated with continuation of routine agricultural practices on existing cultivated lands, implementation of prescribed fire for the purposes of grassland management, and implementation of prescribed grazing following a grazing management plan developed by a Service-approved party.

List of Acronyms

We use many acronyms in this rule. For the convenience of the reader, we define some of them here:

ACEC = Area of Critical Environmental Concern

BLM = Bureau of Land Management

CI = confidence interval

CCAA = candidate conservation agreement with assurances

CCA/CCAA = candidate conservation agreement and candidate conservation agreement with assurances

CDL = Cropland Data Layer

CHAT = Crucial Habitat Assessment Tool

CPW = Colorado Parks and Wildlife

CRP = Conservation Reserve Program

DOE = Department of Energy

DPS = Distinct Population Segment

EOR = Estimated occupied range

EOR+10 = Estimated occupied range plus a 10-mile buffer

FSA = U.S. Department of Agriculture's Farm Services Agency

KDWP = Kansas Department of Wildlife and Parks (formerly KDWPT: Kansas Department of Wildlife, Parks, and Tourism)

LPCI = Lesser Prairie-Chicken Initiative

NRCS = Natural Resources Conservation Service

ODWC = Oklahoma Department of Wildlife Conservation

PECE = Policy for the Evaluation of Conservation Efforts when Making Listing Decisions

PFW = the Service's Partners for Fish and Wildlife Program

RMPA = Resource Management Plan Amendment

RWP = Lesser Prairie-Chicken Range-wide Conservation Plan

SSA = Species Status Assessment

TPWD = Texas Parks and Wildlife Department

USDA = U.S. Department of Agriculture

USFS = U.S. Forest Service

WAFWA = Western Association of Fish and Wildlife Agencies

LWEG = Land-Based Wind Energy Guidelines

Previous Federal Actions

Please refer to the proposed listing rule for the Northern DPS and the Southern DPS of the lesser prairie-chicken for a detailed description of previous Federal actions concerning this species (86 FR 29432, June 1, 2021).

Summary of Changes From the Proposed Rule

Based upon our review of the public comments, State agency comments, peer review comments, and relevant information that became available since the proposed rule published, we updated information in our species status assessment report, including:

• adding references on the effects of overhead power lines,

• adding a discussion regarding the effects from competition with ring-necked pheasants,

• updating monitoring information related to the translocation efforts in the Sand Sagebrush Ecoregion,

• updating information related to conservation banks,

• updating information related to previous conservation efforts,

• adding discussion regarding the Southern Plains Grassland Program,

• updating information related to the recent purchase by the New Mexico Department of Game and Fish of additional lands to be managed for the lesser prairie-chicken, and

• updating current population abundance information using the 2021 aerial survey results.

We also made changes as appropriate in this final rule. In addition to minor clarifying edits and incorporation of additional information on the species' biology, populations, and threats, this determination differs from the proposal in the following ways:

(1) We included updated population trend data, including survey data made available since the publication of the proposed rule. Some of these population survey results became available after we finalized the SSA report. Thus, though the SSA report does not include those results, we have added them to this final rule and fully considered them in our determinations on the status of the two DPSs.

(2) We included new and updated conservation actions as submitted by commenters during the open comment period.

(3) Based on public comments, we expanded our Significant Portion of the Range analysis to explain why the Sand Sagebrush Ecoregion is not significant.

(4) Based on comments received from State agencies, local governments, industry groups, and private citizens, we have updated the section 4(d) rule to include one new exception from the section 9 take prohibitions:

The new exception is for take incidental to grazing management when land managers are following a site-specific grazing plan developed by a party that has been approved by the Service. When livestock grazing is managed in ways that are compatible with promoting the maintenance of the vegetative characteristics needed by the lesser prairie-chicken, this activity can be an invaluable tool necessary for managing healthy grasslands benefiting the lesser prairie-chicken. Therefore, we consider this new exception from prohibitions to be necessary and advisable to the conservation of the species.

Supporting Documents

A species status assessment (SSA) team prepared an SSA report for the lesser prairie-chicken. The SSA team was composed of Service biologists in consultation with other species experts. The SSA report represents a compilation of the best scientific and commercial data available concerning the status of the species, including the impacts of past, present, and future factors (both negative and beneficial) affecting the species. In accordance with our joint policy on peer review published in the
Federal Register
on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review of listing actions under the Act, we sought the expert opinions of six appropriate specialists regarding the SSA. We received four responses. We also sent the SSA report to the five State fish and wildlife agencies within the range of the lesser prairie-chicken (Colorado, Kansas, New Mexico, Oklahoma, and Texas) and the four primary Federal agencies with whom we work to deliver conservation actions that could benefit the lesser prairie-chicken: the Bureau of Land Management (BLM) the U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS), Farm Service Agency (FSA), and U.S. Forest Service (USFS). These partners include scientists with expertise in management of either the lesser prairie-chicken or the habitat upon which the lesser prairie-chicken depends. We received responses from USFS, BLM, and all five of the State wildlife agencies. Comments and feedback from partners and peer reviewers were incorporated into the SSA report as appropriate and have informed this final rule.

I. Final Listing Determination

Background

Below is a summary of the taxonomy, life history, and ecology of the lesser prairie-chicken; for a thorough review, please see the SSA report (version 2.3; Service 2022, pp. 5-14).

The lesser prairie-chicken is in the order Galliformes, family Phasianidae, subfamily Tetraoninae; it is generally recognized as a species separate from the greater prairie-chicken (
Tympanuchus cupido pinnatus
) (Jones 1964, pp. 65-73; American Ornithologist's Union 1998, p. 122).

Most lesser prairie-chicken adults live for 2 to 3 years and reproduce in the spring and summer (Service 2022, pp. 10-12). Males congregate on leks during the spring to attract and mate with females (Copelin 1963, p. 26; Hoffman 1963, p. 730; Crawford and Bolen 1975, p. 810; Davis et al. 1979, p. 84; Merchant 1982, p. 41; Haukos 1988, p. 49). Male prairie-chickens tend to exhibit strong breeding site fidelity, often returning to a specific lek many times, even in cases of declining female attendance and habitat condition (Copelin 1963, pp. 29-30; Hoffman 1963, p. 731; Campbell 1972, pp. 698-699, Hagen et al. 2005, entire, Harju et al. 2010, entire). Females tend to establish nests relatively close to the lek, commonly within 0.6 to 2.4 mile (mi) (1 to 4 kilometers (km)) (Copelin 1963, p. 44; Giesen 1994, p. 97), where they incubate 8 to 14 eggs for 24 to 27 days and then raise broods of young throughout the summer (Boal and Haukos 2016, p. 4). Some females will attempt a second nesting if the first nest fails (Johnsgard 1973, pp. 63-64; Merchant 1982, p. 43; Pitman et al. 2006, p. 25). Eggs and young lesser prairie-chickens are susceptible to natural mortality from environmental stress and predation. The appropriate vegetative community and structure is vital to provide cover for nests and young and to provide food resources as broods mature into adults (Suminski 1977, p. 32; Riley 1978, p. 36; Riley et

al. 1992, p. 386; Giesen 1998, p. 9). For more detail on habitat needs of the lesser prairie-chicken, please see the SSA report (Service 2022, pp. 9-14).

The lesser prairie-chicken once ranged across the Southern Great Plains of Southeastern Colorado, Southwestern Kansas, Western Oklahoma, the Panhandle and South Plains of Texas, and Eastern New Mexico; currently, it occupies a substantially reduced portion of its presumed historical range (Rodgers 2016, p. 15). Estimates of the potential maximum historical range of the lesser prairie-chicken (
e.g.,
Taylor and Guthery 1980a, p. 1, based on Aldrich 1963, p. 537; Johnsgard 2002, p. 32; Playa Lakes Joint Venture 2007, p. 1) range from about 64-115 million acres (ac) (26-47 million hectares (ha)). The more recent estimate of the historical range of the lesser prairie-chicken encompasses an area of approximately 115 million ac (47 million ha). Presumably, not all of the area within this historical range was evenly occupied by lesser prairie-chicken, and some of the area may not have been suitable to regularly support lesser prairie-chicken populations (Boal and Haukos 2016, p. 6). However, the current range of the lesser prairie-chicken has been significantly reduced from the historical range at the time of European settlement. Estimates as to the extent of the loss vary from greater than 90 percent reduction (Hagen and Giesen 2005, unpaginated) to approximately 83 percent reduction (Van Pelt et al. 2013, p. 3).

Lesser prairie-chicken monitoring has been occurring for multiple decades and has included multiple different methodologies. Estimates of population abundance prior to the 1960s are indeterminable and rely almost entirely on anecdotal information (Boal and Haukos 2016, p. 6). While little is known about precise historical population sizes, the lesser prairie-chicken was reported to be quite common throughout its range in the early 20th century (Bent 1932, pp. 280-281, 283; Baker 1953, p. 8; Bailey and Niedrach 1965, p. 51; Sands 1968, p. 454; Fleharty 1995, pp. 38-44; Robb and Schroeder 2005, p. 13). For example, prior to 1900, as many as two million birds may have existed in Texas alone (Litton 1978, p. 1). Information regarding population size is available starting in the 1960s when the State fish and wildlife agencies began routine lesser prairie-chicken monitoring efforts. However, survey methodology and effort have differed over the decades, making it difficult to precisely estimate trends.

The SSA report and this final rule rely on two main population estimates. The two methodologies largely cover different time periods, so we report the results of both throughout this final rule in order to give the best possible understanding of lesser prairie-chicken trends both recently and throughout the past decades.

The first of the two studies used historical lek surveys and population reconstruction methods to calculate historical trends and estimate male abundance from 1965 through 2016 (Hagen et al. (2017, pp. 6-9). We have concerns with some of the methodologies and assumptions made in this analysis including survey effort prior to the 1970s, variation in survey efforts between States, and completeness and accuracy of source data used. Others have also noted the challenges of using these data for long-term trends (for example, Zavaleta and Haukos 2013, p. 545; Cummings et al. 2017, pp. 29-30). While these concerns remain, including the very low sample sizes particularly in the 1960s, this work represents the only attempt to compile the historical ground lek count data collected by State agencies to estimate the number of males at both the range-wide and ecoregional scales, and represents the best available data for understanding historical population trends.

Following development of aerial survey methods (McRoberts et al. 2011, entire), the second summary of lesser prairie-chicken population data uses more statistically rigorous estimates of lesser prairie-chicken abundance (both males and females). This study was designed to address the shortcomings and limitations associated with ground-based survey efforts as discussed above. This second study uses data from aerial line-transect surveys throughout the range of the lesser prairie-chicken; these results are then extrapolated from the surveyed area to the rest of the range (Nasman et al. 2022, entire). The results of these survey efforts should not be taken as precise estimates of the annual lesser prairie-chicken abundance, as indicated by the large confidence intervals associated with these estimates. The confidence intervals are a calculation related to the degree of certainty or uncertainty that the sampling method results in estimates that represent the true population abundance.

Due to the lack of confidence in the precision of these population estimates as reflected by the large confidence intervals, conclusions regarding current population sizes or population changes should not be drawn based upon annual fluctuations. In addition to the large confidence intervals, the lesser prairie-chicken is considered a “boom-bust” species with a high degree of annual variation in rates of successful reproduction and recruitment. These annual and short-term patterns are largely driven by the influence of seasonal precipitation patterns. Periods of below-average precipitation and higher spring/summer temperatures cause less suitable grassland vegetation cover and less food available, resulting in decreased reproductive output (bust periods). Periods with above-normal precipitation and cooler spring/summer temperatures will support favorable habitat conditions and result in higher reproductive success (boom periods). Thus, annual population changes are not a measure of population health but instead largely represent the influence of short-term precipitation cycles whereas long-term population trends are tied to habitat availability. Instead of reporting the annual estimates, the best use of this data is for long-term trend analysis. Thus, in the SSA report and this final rule, we report the population estimate for the current condition as the average of the past 5 years of surveys.

The results of the study using ground-based lek data (abundance of males) indicate that lesser prairie-chicken range-wide abundance (based on a minimum estimated number of male lesser prairie-chickens at leks) peaked during 1965-1970 at a mean estimate of about 175,000 males (figure 1). The estimated mean population maintained levels of greater than 100,000 males until 1989, after which the population steadily declined to a low of 25,000 males in 1997 (Garton et al. 2016, p. 68). The mean population estimates following 1997 peaked again at about 92,000 males in 2006, albeit at a significantly lower value than the prior peak of 175,000. The mean population estimate subsequently declined to 34,440 males in 2012 (figure 1).

The aerial survey results from 2012 through 2022 (figure 2) estimated the lesser prairie-chicken population abundance, averaged over the most recent 5 years of surveys (2017-2022, no surveys in 2019), at 32,210 (including males and females; 90 percent confidence interval: 11,489, 64,303) (Nasman et al. 2022, p. 16; table 10).

ER25NO22.029

The preferred habitat of the lesser prairie-chicken is mixed-grass prairies and shrublands, with the exception of some areas in the northern extent of the range where shrubs play a lesser role. Lesser prairie-chickens appear to select areas having a shrub component dominated by sand sagebrush or sand shinnery oak when those areas are available (Donaldson 1969, pp. 56, 62; Taylor and Guthery 1980a, p. 6; Giesen 1998, pp. 3-4). In the southern and central portions of the lesser prairie-chicken range, small shrubs, such as sand shinnery oak, are important for summer shade (Copelin 1963, p. 37; Donaldson 1969, pp. 44-45, 62), winter protection, and as supplemental foods (Johnsgard 1979, p. 112). In some areas in the northern extent of the species' range, stands of grass that provide adequate vegetative structure likely serve the same roles. The absence of anthropogenic features as well as other vertical structures is important, as lesser prairie-chickens tend to avoid using areas with trees, vertical structures, and other disturbances in areas with otherwise adequate habitat conditions (Braun et al. 2002, pp. 11-13; Pruett et al. 2009, pp. 1256, 1258; Hovick et al. 2014a, p. 1685; Boggie et al. 2017, entire; Lautenbach 2017, pp. 104-142; Plumb et al. 2019, entire).

At the population scale, the most important requirement for the lesser prairie-chicken is having large, intact, ecologically diverse grasslands to complete their life history and maintain healthy populations (Fuhlendorf et al. 2017b, entire). As detailed in chapter 2 of the SSA report, the lesser prairie-chicken requires large ecologically diverse grasslands to meet specific resource needs, in terms of microhabitat conditions, which vary to some degree by life stage and activity (Service 2022, pp. 10-11). Historically, these ecologically diverse grasslands and shrublands were maintained by the occurrence of wildfires (keeping woody vegetation restricted to drainages and rocky outcroppings) and by grazing by bison and other large ungulates. The lesser prairie-chicken is a species that requires large, intact grasslands for functional self-sustaining populations (Giesen 1998, pp. 3-4; Bidwell et al. 2002, pp. 1-3; Hagen et al. 2004, pp. 71, 76-77; Haukos and Zavaleta 2016, p. 107).

The lesser prairie-chicken now occurs within four ecoregions (figure 3); these ecoregions were originally delineated in 2012 as part of the aerial survey designed to monitor long-term trends in lesser prairie-chicken populations. Each ecoregion is associated with unique environmental conditions based on habitat and climatic variables and some genetic differentiation (Boal and Haukos 2016, p. 5; Oyler-McCance et al. 2016, p. 653). These four ecoregions are the Short-Grass Prairie/CRP Ecoregion in Kansas; the Sand Sagebrush Prairie Ecoregion in Colorado, Kansas, and Oklahoma; the Mixed-Grass Prairie Ecoregion in Kansas, Texas, and Oklahoma; and the Shinnery Oak Prairie Ecoregion of New Mexico and Texas.

ER25NO22.030

The Shinnery Oak Ecoregion occupies portions of eastern New Mexico and the South Plains of Texas (McDonald et al. 2012, p. 2). It has a variable vegetation community that contains a mix of shrubs such as sand shinnery oak (
Quercus havardii
) and sand sagebrush (
Artemisia filifolia
) as well as mixed and tall grasses and forbs (Grisham et al. 2016a, p. 317). The mean population estimate ranged between about 5,000 to 12,000 males through 1980, increased to 20,000 males in the mid-1980s and declined to ~1,000 males in 1997 (Hagen et al. 2017, pp. 6-9). The mean population estimate peaked again to ~15,000 males in 2006 and then declined again to fewer than 3,000 males in the mid-2010s. While population estimates for the Shinnery Oak Ecoregion have varied over recent years, the most recent surveys estimate a 5-year average population size of 2,806 birds (including males and females; 90 percent confidence intervals (CI): 179, 9,007). Approximately 9 percent of all lesser prairie-chicken occur in this ecoregion. Lesser prairie-chickens from the Shinnery Oak Ecoregion are genetically distinct and geographically isolated from the other three ecoregions by 95 mi (153 km) (figure 3; Oyler-McCance et al. 2016, p. 653). Historically, the Shinnery Oak Ecoregion was likely connected to the rest of the lesser prairie-chicken range but as a result of habitat loss and fragmentation from European settlement the lesser prairie-chicken in the Shinnery Oak Ecoregion have likely been isolated for over a century (Oyler-McCance et al. 2016, p. 655).

In New Mexico, the majority of the Shinnery Oak Ecoregion is privately owned (Grisham et al. 2016a, p. 315), with some portions owned by the State Game Commission and federally owned BLM lands. Nearly all of the area in the Texas portion of the ecoregion is privately owned and managed for agricultural use and petroleum production (Haukos 2011, p. 110). The remaining patches of shinnery oak prairie have become isolated, relict communities because the surrounding grasslands have been converted to row crop agriculture or fragmented by oil and gas exploration and urban development (Peterson and Boyd 1998, p. 22). Additionally, honey mesquite (
Prosopis glandulosa
) encroachment within this ecoregion has played a significant role in decreasing available space for the lesser prairie-chicken. Technological advances in irrigated row crop agriculture have led to more recent conversion of shinnery oak prairie habitat to row crops in Eastern New Mexico and West Texas (Grisham et al. 2016a, p. 316).

The Sand Sagebrush Ecoregion occurs in Southeast Colorado, Southwest Kansas, and a small portion of Western Oklahoma (McDonald et al. 2012, p. 2). The vegetation community in this area primarily consists of sand sagebrush and the associated mixed and tall grass species that are usually found in the sandier soils adjacent to rivers, streams, and other drainages in the area. Lesser prairie-chicken from the Sand Sagebrush Ecoregion show some genetic differentiation from other ecoregions but have likely contributed some individuals to the Short-Grass/CRP Ecoregion through dispersal (Oyler-McCance et al. 2016, p. 653).

Historically, the Sand Sagebrush Ecoregion supported the highest density of lesser prairie-chicken and was considered the core of the lesser prairie-chicken range (Haukos et al. 2016, p. 282). A single flock detected in Seward County, Kansas, was estimated to contain more than 15,000 birds (Bent 1932, p. 281). The population size is estimated to have peaked at more than 85,000 males in the 1970s (Garton et al. 2016, p. 62). More recent survey efforts estimate a 5-year average population size of 1,297 birds (including males and females; 90 percent CI: 56, 4,881; Nasman et al. 2022, p. 16). Less than 5 percent of all lesser prairie-chicken occur in this ecoregion (Service 2022, pp. 64-78). Most of the decline has been attributed to habitat deterioration and conversion of sand sagebrush to intensive row crop agriculture due to an increase in center pivot irrigation (Jensen et al. 2000, p. 172). Environmental conditions in this ecoregion can be extreme, with stochastic events such as blizzards negatively impacting lesser prairie-chicken populations.

The Short-Grass/CRP Ecoregion falls within the mixed- and short-grass prairies of Central and Western Kansas (McDonald et al. 2012, p. 2). As the name implies, much of this ecoregion historically consisted of short-grass prairie interspersed with mixed-grass prairie as well as sand sagebrush prairie along some drainages (Dahlgren et al. 2016, p. 260). By the 1980s, large expanses of prairies had been converted from native grass for crop production in this ecoregion. After the introduction of the CRP in 1985, landowners began to have enhanced incentives to convert croplands to perennial grasslands to provide cover for the prevention of soil erosion. The State of Kansas required those enrolling in the CRP to plant native mixed- and tall-grass species, which is notable because the grasses in this area historically consisted largely of short-grass species, which generally do not provide adequate habitat for the lesser prairie-chicken. For more information on the CRP, see the SSA report (Service 2022, pp. 52-54).

Prior to the late 1990s, lesser prairie-chickens in this ecoregion were thought to be largely absent (or occurred sporadically in low densities) (Hagen and Giesen 2005, unpaginated; Rodgers 1999, p. 19). We do not know what proportion of the eastern Short-Grass/CRP Ecoregion in Kansas was historically occupied by lesser prairie-chicken (Hagen 2003, pp. 3-4), and surveys in this ecoregion only began in earnest in 1999 (Dahlgren et al. 2016, p. 262). The CRP is an idle lands program, which requires establishment of grass cover and precludes tillage or agricultural commodity production for the duration of the contract, and has contractual limits to the type, frequency, and timing of management activities, such as burning, haying, or grazing of the established grasses. As a result of these factors, CRP often provides the vegetative structure preferentially used by lesser prairie-chickens for nesting. In the State of Kansas, the availability of CRP lands, especially CRP lands with interseeded or original seed mixture of forbs, resulted in increased habitat availability for the lesser prairie-chicken and, thus, an expansion of the known lesser prairie-chicken range and an increase in the abundance of the lesser prairie-chicken (Rodgers 1999, pp. 18-19; Fields 2004, pp. 11, 105; Fields et al. 2006, pp. 931, 937; Sullins et al. 2018, p. 1617).

The Short-Grass/CRP Ecoregion is now estimated to contain the majority of lesser prairie-chickens compared to the other ecoregions, with recent survey efforts estimating a 5-year average population size of 23,083 birds (including males and females; 90 percent CI: 9,653, 39,934), representing approximately 72 percent of the rangewide population. Recent genetic studies indicate that lesser prairie-chickens have moved northward largely from the Mixed-Grass Ecoregion and, to a lesser extent, the Sand Sagebrush Ecoregion into the Short-Grass/CRP Ecoregion (Oyler-McCance et al. 2016, p. 653).

The northern section of this ecoregion is the only portion of the lesser prairie-chicken's range where co-occurrence with greater prairie-chicken occurs. Hybridization rates of up to 5 percent have been reported (Pitman 2013, p. 5), and that rate seemed to be stable across multiple years, though sampling is limited where the species co-occur (Pitman 2013, p. 12). Limited additional work has been completed to further assess the rate of hybridization. There are concerns about the implications of genetic introgression (dilution) of lesser prairie-chicken genes, particularly given that potential effects are poorly understood (Dahlgren et al. 2016, p. 276). Unresolved issues include whether hybridization reduces fitness and alters behavior or morphological traits in either a positive or negative way and the historical occurrence and rate of hybridization.

The Mixed-Grass Ecoregion for the lesser prairie-chicken lies in the northeastern panhandle of Texas, the panhandle of northwestern Oklahoma, and south-central Kansas (McDonald et al. 2012, p. 2). The Mixed-Grass Ecoregion is separated from the Short-Grass/CRP Ecoregion in Kansas by the Arkansas River. The vegetation community in this ecoregion consists largely of a mix of perennial grasses and shrubs such as sand sagebrush, sand plum (
Prunus angustifolia
), yucca (
Yucca
spp.), and sand shinnery oak (Wolfe et al. 2016, p. 300). Based upon population reconstruction data, the mean population estimate was around 30,000 males in the 1970s and 1980s followed by a decline in the 1990s (Hagen et al. 2016, pp. 6-7). The mean population estimate peaked again in the early 2000s at around 25,000 males, before declining to and remaining at its lowest levels, less than 10,000 males since 2012 (Hagen et al. 2016, pp. 6-7). Although historical population estimates in the ecoregion reported some of the highest densities of lesser prairie-chicken in the range (Wolfe et al. 2016, p. 299), recent aerial survey efforts estimate a 5-year average population size of 5,024 birds (including males and females; 90 percent CI: 1,601, 10,481). The recent survey work indicates that about 15 percent of lesser prairie-chicken occur in this ecoregion. Lesser prairie-chicken from the Mixed-Grass Ecoregion are similar in genetic variation with the Short-Grass/CRP Ecoregion, with individuals likely dispersing from the Mixed-Grass Ecoregion to the Short-Grass/CRP Ecoregion (Oyler-McCance et al. 2016, p. 653).

Distinct Population Segment Evaluation

Under the Act, the term “species” includes “any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature.” 16 U.S.C. 1532(16). To guide the implementation of the distinct population segment (DPS) provisions of the Act, we and the National Marine Fisheries Service (National Oceanic and Atmospheric Administration—Fisheries), published

the Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act (DPS Policy) in the
Federal Register
on February 7, 1996 (61 FR 4722). Under our DPS Policy, we use two elements to assess whether a population segment under consideration for listing may be recognized as a DPS: (1) The population segment's discreteness from the remainder of the species to which it belongs, and (2) the significance of the population segment to the species to which it belongs. If we determine that a population segment being considered for listing is a DPS, then the population segment's conservation status is evaluated based on the five listing factors established by the Act to determine if listing it as either endangered or threatened is warranted.

As described in Previous Federal Actions, we were petitioned to list the lesser prairie-chicken either rangewide or in three distinct population segments. The petition suggested three DPS configurations: (1) Shinnery Oak Ecoregion, (2) the Sand Sagebrush Ecoregion, and (3) a segment including the Mixed-Grass Ecoregion and the Short-Grass/CRP Ecoregion. The petition combined the Mixed-Grass Ecoregion and the Short-Grass/CRP Ecoregion due to evidence they are linked genetically and geographically (Molver 2016, p. 18). Genetic studies indicate that lesser prairie-chicken from the Mixed-Grass Ecoregion are similar in genetic variation with the Short-Grass/CRP Ecoregion, with individuals likely dispersing from the Mixed-Grass Ecoregion to the Short-Grass/CRP Ecoregion (Oyler-McCance et al. 2016, p. 653). Other genetic data indicate that lesser prairie-chicken from the Sand Sagebrush Ecoregion and lesser prairie-chicken from the Mixed-Grass and Short-Grass/CRP Ecoregion also share genetic traits. Genetic studies of neutral markers indicate that, although lesser prairie-chicken from the Sand Sagebrush Ecoregion form a distinct genetic cluster from other ecoregions, they have also likely contributed some individuals to the Short-Grass/CRP Ecoregion through dispersal (Oyler-McCance et al. 2016, p. 653). Additionally, these three ecoregions are not geographically isolated from one another (figure 3). As a result of the shared genetic characteristics and the geographic connections, we have concluded a “Northern” population segment of the species that includes the Sand Sagebrush Ecoregion, the Mixed-Grass Ecoregion, and the Short-Grass/CRP Ecoregion is appropriately considered a potential DPS configuration.

Under the Act, we have the authority to consider for listing any species, subspecies, or, for vertebrates, any distinct population segment (DPS) of these taxa if there is sufficient information to indicate that such action may be warranted. We considered whether two segments meet the DPS criteria under the Act: a “Southern” population segment, including the southernmost ecoregion (Shinnery Oak), and a “Northern” population segment, including the three northernmost ecoregions (Mixed-Grass, Short-Grass/CRP, and Sand Sagebrush).

Discreteness

Under our DPS Policy, a population segment of a vertebrate taxon may be considered discrete if it satisfies either 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.

We conclude the two segments satisfy the “markedly separate” condition. The two segments are not separated from each other by international governmental boundaries. The southern population segment (which includes the Shinnery Oak ecoregion) is separated from the northern population segment (which includes the three northern ecoregions) by approximately 95 mi (153 km). Most of this separation between the two segments is developed or otherwise unsuitable habitat. There has been no recorded movement of lesser prairie-chickens between the Shinnery Oak Ecoregion and the three northern ecoregions over the past several decades. Because there is no connection between the two population segments, there is subsequently no gene flow between them (Oyler-McCance et al. 2016, entire).

Therefore, we have determined that both a southern segment and a northern segment of the lesser prairie-chicken range both individually meet the condition for discreteness under our DPS Policy.

Significance

Under our DPS Policy, once we have determined that a population segment is discrete, we consider its biological and ecological significance to the larger taxon to which it belongs. This consideration may include, but is not limited to: (1) Evidence of the persistence of the discrete population segment in an ecological setting that is unusual or unique for the taxon, (2) evidence that loss of the population segment would result in a significant gap in the range of the taxon, (3) evidence that the population segment represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historical range, or (4) evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics.

For the lesser prairie-chicken, we first considered evidence that the Shinnery Oak Ecoregion population segment differs markedly from the other populations of the species,
i.e.,
the ecoregions that constitute the Northern population segment (Mixed-Grass Ecoregion, Short-Grass/CRP Ecoregion, and Sand Sagebrush Ecoregion) in its genetic characteristics. The most recent rangewide genetic study examined neutral markers in the four ecoregions where the lesser prairie-chicken occurs. It concluded that there is significant genetic variation across the lesser prairie-chicken range. The study also concluded that although there is genetic exchange between the three northern ecoregions (particularly movement of birds northward from the Mixed-Grass Ecoregion to the Short-Grass/CRP Ecoregion, and, to a lesser extent, from the Sand Sagebrush Ecoregion into the Short-Grass/CRP Ecoregion), lesser prairie-chicken from the Shinnery Oak Ecoregion that make up the southern population segment) are a group that is genetically distinct from the remainder of the range,
i.e.,
the northern population segment (Oyler-McCance et al. 2016, p. 653). The Shinnery Oak Ecoregion is more distinct from all three ecoregions in the Northern population segment than those ecoregions are from each other (Oyler-McCance et al. 2016, table 4). The Shinnery Oak Ecoregion was likely historically connected to the remainder of the range, but the two parts have been separated since approximately the time of European settlement. Therefore, the two segments of the range are genetically distinct from each other and therefore significant to the taxon as a whole.

We next considered evidence that loss of the population segment would result in a significant gap in the range of the taxon. As discussed above, the southern population segment and the northern

population segment are separated by approximately 95 mi (153 km). The loss of the Shinnery Oak Ecoregion would result in the loss of the entire southern part of the species' range and decrease species redundancy and ecological and genetic representation, thus decreasing its ability to withstand demographic and environmental stochasticity. The loss of the other three ecoregions would result in the loss of 75 percent of the species' range, as well as loss of the part of the range (the Short-Grass/CRP Ecoregion) that has recently experienced an expansion of occupied habitat. This would create a large gap in the northern portion of the species' range, also reducing the species' ability to withstand demographic and environmental stochasticity. Therefore, the loss of either part of the range would result in a significant gap in the range of the lesser prairie-chicken. These genetic differences and the evidence that a significant gap in the range of the taxon would result from the loss of either discrete population segment both individually satisfy the significance criterion of the DPS Policy. Therefore, under the Service's DPS Policy, we find that both the southern and northern segments of the lesser prairie-chicken are significant to the taxon as a whole.

Distinct Population Segment Conclusion

Our DPS Policy directs us to evaluate the significance of a discrete population in the context of its biological and ecological significance to the remainder of the species to which it belongs. Based on an analysis of the best available scientific and commercial data, we conclude that the northern and southern parts of the lesser prairie-chicken range are discrete due to geographic (physical) isolation from the remainder of the taxon. Furthermore, we conclude that both parts of the lesser prairie-chicken range are significant, because loss of either part would result in a significant gap in the range of the taxon, and because the two parts of the range differ markedly from each other based on neutral genetic markers. Therefore, we conclude that both the northern and southern parts of the lesser prairie-chicken range are both discrete and significant under our DPS Policy and are, therefore, uniquely listable entities under the Act.

Based on our DPS Policy (61 FR 4722; February 7, 1996), if a population segment of a vertebrate species is both discrete and significant relative to the taxon as a whole (
i.e.,
it is a distinct population segment), its evaluation for endangered or threatened status will be based on the Act's definition of those terms and a review of the factors enumerated in section 4(a) of the Act. Having found that both parts of the lesser prairie-chicken range meet the definition of a distinct population segment, we evaluate the status of both the Southern DPS and the Northern DPS of the lesser prairie-chicken to determine whether either meets the definition of an endangered or threatened species under the Act. The line demarcating the break between the Northern and Southern DPS lies approximately halfway between the two DPSs in the unoccupied area between them (figure 4).

ER25NO22.031

Regulatory and Analytical Framework

Regulatory Framework

Section 4 of the Act (16 U.S.C. 1533) and its implementing regulations (50 CFR part 424) set forth the procedures for determining whether a species is an endangered species or a threatened species, issuing protective regulations for threatened species, and designating critical habitat for threatened and endangered species. In 2019, jointly with the National Marine Fisheries Service, the Service issued final rules that revised the regulations in 50 CFR parts 17 and 424 regarding how we add, remove, and reclassify threatened and endangered species and the criteria for designating listed species' critical habitat (84 FR 45020 and 84 FR 44752; August 27, 2019). At the same time the Service also issued final regulations that, for species listed as threatened species after September 26, 2019, eliminated the Service's general protective regulations automatically applying to threatened species the prohibitions that section 9 of the Act applies to endangered species (collectively, the 2019 regulations).

As with the proposed rule, we are applying the 2019 regulations for this final rule because the 2019 regulations are currently in effect, just as they were when we completed the proposed rule. Although there was a period in the

interim—between July 5, 2022, and September 21, 2022—when the 2019 regulations became vacated and the pre-2019 regulations therefore governed, the 2019 regulations are now in effect and govern listing and critical habitat decisions (
see Center for Biological Diversity
v.
Haaland,
No. 4:19-cv-05206-JST, Doc. 168 (N.D. Cal. July 5, 2022) (
CBD
v.
Haaland
) (vacating the 2019 regulations and thereby reinstating the pre-2019 regulations)) and
In re: Cattlemen's Ass'n,
No. 22-70194 (9th Cir. Sept. 21, 2022) (staying the vacatur of the 2019 regulations and thereby reinstating the 2019 regulations until a pending motion for reconsideration before the district court is resolved)).

The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range, and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The Act requires that we determine whether any species is an endangered species or a threatened species because of any of the following factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and conditions, we look for those that may have a negative effect on individuals of the species, as well as other actions or conditions that may ameliorate any negative effects or may have positive effects.

We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself.

However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the species' expected response and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species, such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the definition of an “endangered species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species now and in the foreseeable future.

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis. The term “foreseeable future” extends only so far into the future as we can reasonably determine that both the future threats and the species' responses to those threats are likely. In other words, the foreseeable future is the period of time in which we can make reliable predictions. “Reliable” does not mean “certain”; it means sufficient to provide a reasonable degree of confidence in the prediction. Thus, a prediction is reliable if it is reasonable to depend on it when making decisions.

It is not always possible or necessary to define foreseeable future as a particular number of years. Analysis of the foreseeable future uses the best scientific and commercial data available and should consider the timeframes applicable to the relevant threats and to the species' likely responses to those threats in view of its life-history characteristics. Data that are typically relevant to assessing the species' biological response include species-specific factors such as lifespan, reproductive rates or productivity, certain behaviors, and other demographic factors.

Analytical Framework

The SSA report documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the species, including an assessment of the potential threats to the species. The SSA report does not represent our decision on whether the species should be listed as an endangered or threatened species under the Act. However, it does provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies. The following is a summary of the key results and conclusions from the SSA report; the full SSA report can be found at Docket FWS-R2-ES-2021-0015 on
https://www.regulations.gov.

To assess lesser prairie-chicken viability, we used the three conservation biology principles of resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency supports the ability of the species to withstand environmental and demographic stochasticity (for example, wet or dry, warm or cold years), redundancy supports the ability of the species to withstand catastrophic events (for example, droughts, large pollution events), and representation supports the ability of the species to adapt over time to long-term changes in the environment (for example, climate changes). In general, the more resilient and redundant a species is and the more representation it has, the more likely it is to sustain populations over time, even under changing environmental conditions. Using these principles, we identified the species' ecological requirements for survival and reproduction at the individual, population, and species levels, and described the beneficial and risk factors influencing the species' viability.

The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs. The next stage involved an assessment of the historical and current condition of the species' demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about the species' responses to positive and negative environmental and anthropogenic influences. Throughout all of these stages, we used the best available information to characterize viability as the ability of a species to sustain populations in the wild over time. We use this information to inform our regulatory decision.

Summary of Biological Status and Threats

In this discussion, we review the biological condition of the species and

its resources, and the threats that influence the species' current and future condition, in order to assess the species' overall viability and the risks to that viability.

We note that, by using the SSA framework to guide our analysis of the scientific information documented in the SSA report, we have not only analyzed individual effects on the species, but we have also analyzed their potential cumulative effects. We incorporate the cumulative effects into our SSA analysis when we characterize the current and future condition of the species. To assess the current and future condition of the species, we undertake an iterative analysis that encompasses and incorporates the threats individually and then accumulates and evaluates the effects of all the factors that may be influencing the species, including threats and conservation efforts. Because the SSA framework considers not just the presence of the factors, but to what degree they collectively influence risk to the entire species, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative effects analysis.

Representation

To evaluate representation as a component of lesser prairie-chicken viability, we considered the need for multiple healthy lesser prairie-chicken populations within each of the four ecoregions to conserve the genetic and ecological diversity of the lesser prairie-chicken. Each of the four ecoregions varies in terms of vegetative communities and environmental conditions, resulting in differences in abundance and distribution and management strategies (Boal and Haukos 2016, p. 5). Despite reduced range and population size, most lesser prairie-chicken populations appear to have maintained comparatively high levels of neutral genetic variation (DeYoung and Williford 2016, p. 86). As discussed in
Significance
above, recent genetic studies also show significant genetic variation across the lesser prairie-chicken range based on neutral markers (Service 2022, figure 2.4), which supports management separation of these four ecoregions and highlights important genetic differences between them (Oyler-McCance et al. 2016, p. 653). While it is unknown how this genetic variation relates to differences in adaptive capacity between the ecoregions, maintaining healthy lesser prairie-chicken populations across this range of diversity increases the likelihood of conserving inherent ecological and genetic variation within the species to enhance its ability for adaptation to future changes in environmental conditions.

Resiliency

In the case of the lesser prairie-chicken, we considered the primary indicators of resiliency to be habitat availability, population abundance, growth rates, and quasi-extinction risk. Lesser prairie-chicken populations within ecoregions must have sufficient habitat and population growth potential to recover from natural disturbance events such as extensive wildfires, extreme hot or cold events, extreme precipitation events, or extended local periods of below-average rainfall. These events can be particularly devastating to populations when they occur during the late spring or summer when nesting and brood-rearing are occurring and individuals are more susceptible to mortality.

The lesser prairie-chicken is considered a “boom-bust” species based on its high reproductive potential with a high degree of annual variation in rates of successful reproduction and recruitment. These variations are largely driven by the influence of seasonal precipitation patterns (Grisham et al. 2013, pp. 6-7), which impact the population through effects on the quality of habitat. Periods of below-average precipitation and higher spring/summer temperatures result in less appropriate grassland vegetation cover and less food available, resulting in decreased reproductive output (bust periods). Periods with above-normal precipitation and cooler spring/summer temperatures will support favorable lesser prairie-chicken habitat conditions and result in high reproductive success (boom periods). In years with particularly poor weather conditions, individual female lesser prairie-chicken may forgo nesting for the year. This population characteristic highlights the need for habitat conditions to support large population growth events during favorable climatic conditions so they can withstand the declines during poor climatic conditions without a high risk of extirpation.

Historically, the lesser prairie-chicken had large expanses of grassland habitat to maintain populations. Early European settlement and development of the Southern Great Plains for agriculture initially, and for energy extraction later, substantially reduced the amount and connectivity of the grasslands of this region. Additionally, if historically some parts of the range were drastically impacted or eliminated due to a stochastic event, that area could be reestablished from other populations. Today, those characteristics of the grasslands have been degraded, resulting in the loss and fragmentation of grasslands in the Southern Great Plains. Under present conditions, the potential lesser prairie-chicken habitat is limited to small, fragmented grassland patches (relative to historical conditions) (Service 2022, pp. 64-78). The larger and more intact the remaining grassland patches are, with appropriate vegetation structure, the larger, healthier, and more resilient the lesser prairie-chicken populations will be. Exactly how large habitat patches should be to support healthy populations depends on the quality and intactness of the patches. Recommended total space needed for a single lesser prairie-chicken lek ranges from a minimum of about 12,000 ac (4,900 ha) (Davis 2005, p. 3) up to more than 50,000 ac (20,000 ha), depending on the quality and intactness of the area (Applegate and Riley 1998, p. 14; Haufler et al. 2012, pp. 7-8; Haukos and Zavaleta 2016, p. 107).

A single lesser prairie-chicken lek is not considered a population that can persist on its own. Instead, complexes of multiple leks that interact with each other are required for a lesser prairie-chicken population to persist over time. These metapopulation dynamics, in which individuals interact on the landscape to form larger populations, are dependent upon the specific biotic and abiotic landscape characteristics of the site and how those characteristics influence space use, movement, patch size, and fragmentation (DeYoung and Williford 2016, pp. 89-91). Maintaining multiple, highly resilient populations (complexes of leks) within the four ecoregions that have the ability to interact with each other will increase the probability of persistence in the face of environmental fluctuations and stochastic events. Because of this concept of metapopulations and their influence on long-term persistence, when evaluating lesser prairie-chicken populations, site-specific information can be informative. However, many of the factors affecting lesser prairie-chicken populations should be analyzed at larger spatial scales (Fuhlendorf et al. 2002, entire).

Redundancy

Redundancy describes the ability of a species to withstand catastrophic events. Catastrophes are stochastic events that are expected to lead to population collapse regardless of population health and for which adaptation is unlikely. Redundancy spreads the risk and can be measured through the duplication and distribution

of resilient populations that are connected across the range of the species. The larger the number of highly resilient populations the lesser prairie-chicken has, distributed over a large area within each ecoregion, the better the species can withstand catastrophic events. Catastrophic events for lesser prairie-chicken might include extreme drought; widespread, extended droughts; or a disease outbreak.

Measuring redundancy for lesser prairie-chicken is a difficult task due to the physiological and biological characteristics of the species, which make it difficult to survey and limit the usefulness of survey results. To estimate redundancy for the lesser prairie-chicken, we estimated the geographic distribution of predicted available habitat within each of the four ecoregions and the juxtaposition of that habitat to other habitat and non-habitat. As the amount of large grassland patches decreases and grassland patches become more isolated to reduce or preclude lesser prairie-chicken movement between them, the overall redundancy of the species is reduced. As redundancy decreases within any representative ecoregion or DPS, the likelihood of extirpation within that ecoregion or DPS increases. As large grassland patches, the connectivity of those patches, and the number of lesser prairie-chicken increase, so does the redundancy within an ecoregion or a DPS.

Current Condition

In the SSA report, we assessed the current condition of the lesser prairie-chicken through an analysis of existing habitat; a review of factors that have impacted the species in the past, including a geospatial analysis to estimate areas of land cover impacts on the current landscape condition; a summary of the current potential usable area based upon our geospatial analysis; and a summary of past and current population estimates. We also evaluated and summarized the benefits of the extensive conservation efforts that are ongoing throughout the lesser prairie-chicken range to conserve the species and its habitat.

Geospatial Analysis Summary

The primary concern for the lesser prairie-chicken is habitat loss and fragmentation. We conducted a geographic information system (GIS) analysis to analyze the extent of usable land cover changes and fragmentation within the range of the lesser prairie-chicken, characterizing landscape conditions spatially to analyze the ability of those landscapes to support the biological needs of the lesser prairie-chicken. Impacts included in this analysis were the direct and indirect effects of areas that were converted to cropland; encroached by woody vegetation such as mesquite and eastern red cedar (
Juniperus virginiana
); and developed for roads, petroleum production, wind energy, and transmission lines. We acknowledge that there are other impacts, such as power lines or incompatible grazing on the landscape that can affect lesser prairie-chicken habitat. For those impacts, either no geospatial data were available, or the available data would have added so much complexity to our geospatial model that the results would have been uninterpretable or not explanatory for our purpose.

There are several important limitations to our geospatial analysis. First, it is a landscape-level analysis, so the results only represent broad trends at the ecoregional and rangewide scales. Secondly, this analysis does not incorporate different levels of habitat quality, as the data do not exist at the spatial scale or resolution needed. Our analysis considers areas only as either potentially usable or not usable by lesser prairie-chicken based upon land cover classifications. We recognize that some habitat, if managed as high-quality grassland, may have the ability to support higher densities of lesser prairie-chicken than other habitat that exists at lower qualities. Additionally, we also recognize that some areas of land cover that we identified as suitable could be of such poor quality that it is of limited value to the lesser prairie-chicken. We recognize there are many important limitations to this landscape analysis, including variation and inherent error in the underlying data and unavailable data. We interpreted the results of this analysis with those limitations in mind.

In this final rule, we discuss effects that relate to the total potential usable unimpacted acreage for lesser prairie-chicken, as defined by our geospatial analysis (hereafter, analysis area). A complete description of the purpose, methodology, constraints, and additional details for this analysis is provided in the SSA report for the lesser prairie-chicken (Service 2022, appendix B, parts 1, 2, and 3).

Threats Influencing Current Condition

Following are summary evaluations of the threats analyzed in the SSA report for the lesser prairie-chicken: effects associated with habitat degradation, loss, and fragmentation, including conversion of grassland to cropland (Factor A), petroleum production (Factor A), wind energy development and transmission (Factor A), woody vegetation encroachment (Factor A), and roads and electrical distribution lines (Factor A); other factors, such as livestock grazing (Factor A), shrub control and eradication (Factor A), collision mortality from fences (Factor E), predation (Factor C), influence of anthropogenic noise (Factor E), fire (Factor A); and extreme weather events (Factor E). We also evaluate existing regulatory mechanisms (Factor D) and ongoing conservation measures.

In the SSA report, we also considered three additional threats: hunting and other recreational, educational, and scientific use (Factor B); parasites and diseases (Factor C); and insecticides (Factor E). We concluded that, as indicated by the best available scientific and commercial information, these threats are currently having little to no impact on lesser prairie-chickens and their habitat, and thus their overall effect now and into the future is expected to be minimal. Therefore, we will not present summary analyses of those threats in this document but will consider them in our overall conclusions of impacts to the species. For full descriptions of all threats and how they impact the species, please see the SSA report (Service 2022, pp. 24-49).

Habitat Degradation, Loss, and Fragmentation

The grasslands of the Great Plains are among the most threatened ecosystems in North America (Samson et al. 2004, p. 6) and have been impacted more than any other major ecosystem on the continent (Samson and Knopf 1994, p. 418). Temperate grasslands are also one of the least conserved ecosystems (Hoekstra et al. 2005, p. 25). Grassland loss in the Great Plains is estimated at approximately 70 percent (Samson et al. 2004, p. 7), with nearly 23 million ac (93,000 km
2
; 9.3 million ha) of grasslands in the United States lost between 1982 and 1997 alone (Samson et al. 2004, p. 9). The vast majority of the lesser prairie-chicken range (more than 95 percent) occurs on private lands that have been in some form of agricultural production since at least the early 1900s. As a result, available habitat for grassland species, such as the lesser prairie-chicken, has been much reduced and fragmented compared to historical conditions across its range.

Habitat impacts occur in three general categories that often work synergistically at the landscape scale: degradation, loss, and fragmentation. Habitat degradation results in changes to a species' habitat that reduces its

suitability to the species, but without making the habitat entirely unsuitable. Degradation may result in lower carrying capacity, lower reproductive potential, higher predation rates, or other effects. Habitat loss may result from the same anthropogenic sources that cause degradation, but the habitat has been altered to the point where it has no suitability for the species at all. Habitat fragmentation occurs when habitat loss is patchy and leaves a matrix of grassland habitat behind. While habitat degradation continues to be a concern, we focus our analysis on habitat loss and fragmentation from the cumulative effects of multiple sources of activities as the long-term drivers of the species' viability.

Initially, reduction in the total area of available habitat may be more significant than fragmentation and can exert a much greater effect on populations (Fahrig 1997, pp. 607, 609). However, as habitat loss continues, the effects of fragmentation often compound effects of habitat loss and produce even greater population declines than habitat loss alone (Bender et al. 1998, pp. 517-518, 525). Spatial habitat fragmentation occurs when some form of disturbance, usually habitat degradation or loss, results in the separation or splitting apart of larger, previously contiguous, functional components of habitat into smaller, often less valuable, noncontiguous patches (Wilcove et al. 1986, p. 237; Johnson and Igl 2001, p. 25; Franklin et al. 2002, entire). Habitat loss and fragmentation influence habitat availability and quality in three primary ways: (1) total area of available habitat constrains the maximum population size for an area; (2) the size of habitat patches within a larger habitat area, including edge effects (changes in population or community structures that occur at the boundary of two habitats), influences habitat quality and size of local populations; and (3) patch isolation influences the amount of species movement between patches, which constrains demographic and genetic exchange and ability to recolonize local areas where the species might be extirpated (Johnson and Igl 2001, p. 25; Stephens et al. 2003, p. 101).

Habitat loss, fragmentation, and degradation correlate with the ecological concept of carrying capacity. Within any given block or patch of lesser prairie-chicken habitat, carrying capacity is the maximum number of birds that can be supported indefinitely by the resources available within that area, that is, sufficient food, shelter, and lekking, nesting, brood-rearing, and wintering areas. As habitat loss increases and the size of an area decreases, the maximum number of birds that can inhabit that particular habitat patch also decreases. Consequently, a reduction in the total area of available habitat can negatively influence biologically important characteristics such as the amount of space available for establishing territories and nest sites (Fahrig 1997, p. 603). Over time, the continued conversion and loss of habitat will reduce the capacity of the landscape to support historical population levels, causing a decline in population sizes.

Habitat loss not only contributes to overall declines in usable area for a species but also causes a reduction in the size of individual habitat patches and influences the proximity and connectivity of these patches to other patches of similar habitat (Stephens et al. 2003, p. 101; Fletcher 2005, p. 342), reducing rates of movement between habitat patches until, eventually, complete isolation results. Habitat quality for many species is, in part, a function of patch size and declines as the size of the patch decreases (Franklin et al. 2002, p. 23). Both the size and shape of the habitat patch have been shown to influence population persistence in many species (Fahrig and Merriam 1994, p. 53). The size of the fragment can influence reproductive success, survival, and movements. As the distances between habitat fragments increase, the rate of dispersal between the habitat patches may decrease and ultimately cease, reducing the likelihood of population persistence and potentially leading to both localized and regional extinctions (Harrison and Bruna 1999, p. 226; With et al. 2008, p. 3153). In highly fragmented landscapes, once a species becomes extirpated from an area, the probability of recolonization is greatly reduced (Fahrig and Merriam 1994, p. 52).

For the lesser prairie-chicken, habitat loss can occur due to either direct or indirect habitat impacts. Direct habitat loss is the result of the removal or alteration of grasslands, making that space no longer available for use by the lesser prairie-chicken. Indirect habitat loss and degradation is when the vegetation still exists, but the areas adjacent to a disturbance (the disturbance can be natural or manmade) are no longer used by lesser prairie-chicken or are used at reduced rates, or the disturbance negatively alters demographic rates or behavior in the affected area. In many cases, as discussed in detail below for specific disturbances, the indirect habitat loss can greatly exceed the direct habitat loss.

Primarily due to their site fidelity and the need for large, ecologically diverse landscapes, lesser prairie-chickens appear to be relatively intolerant to habitat alteration, particularly for activities that fragment habitat into smaller patches. The birds require habitat patches with large expanses of vegetative structure in different successional stages to complete different phases in their life cycle, and the loss or partial loss of even one of these structural components can significantly reduce the overall value of that habitat to lesser prairie-chickens (Elmore et al. 2013, p. 4). In addition to the impacts on the individual patches, as habitat loss and fragmentation increases on the landscape, the juxtaposition of habitat patches to each other and to non-habitat areas will change. This changing pattern on the landscape can be complex and difficult to predict, but the results, in many cases, are increased isolation of individual patches (either due to physical separation or barriers preventing or limiting movement between patches) and direct impacts to metapopulation structure, which could be important for population persistence (DeYoung and Williford 2016, pp. 88-91).

The following sections provide a discussion and quantification of the influence of habitat loss and fragmentation on the grasslands of the Great Plains within the lesser prairie-chicken analysis area and more specifically allow us to characterize the current condition of lesser prairie-chicken habitat.

Conversion of Grassland to Cropland

Historical conversion of grassland to cultivated agricultural lands in the late 19th century and throughout the 20th century has been regularly cited as an important cause in the rangewide decline in abundance and distribution of lesser prairie-chicken populations (Copelin 1963, p. 8; Jackson and DeArment 1963, p. 733; Crawford and Bolen 1976a, p. 102; Crawford 1980, p. 2; Taylor and Guthery 1980b, p. 2; Braun et al. 1994, pp. 429, 432-433; Mote et al. 1999, p. 3). Because cultivated grain crops may have provided increased or more dependable winter food supplies for lesser prairie-chickens (Braun et al. 1994, p. 429), the initial conversion of smaller patches of grassland to cultivation may have been temporarily beneficial to the short-term needs of the species as primitive and inefficient agricultural practices made grain available as a food source (Rodgers 2016, p. 18). However, as conversion increased, it became clear that landscapes having greater than 20 to 37

percent cultivated grains may not support stable lesser prairie-chicken populations (Crawford and Bolen 1976a, p. 102). More recently, abundances of lesser prairie-chicken increased with increasing cropland until a threshold of 10 percent was reached; after that, abundance of lesser prairie-chicken declined with increasing cropland cover (Ross et al. 2016b, entire). While lesser prairie-chicken may forage in agricultural croplands, croplands do not provide for the habitat requirements of the species' life cycle (cover for nesting and thermoregulation); thus, lesser prairie-chicken avoid landscapes dominated by cultivated agriculture, particularly where small grains are not the dominant crop (Crawford and Bolen 1976a, p. 102).

As part of the geospatial analysis completed for the SSA, we estimated the amount of cropland that currently exists in the four ecoregions of the lesser prairie-chicken. These percentages do not equate to the actual proportion of habitat loss in the analysis area because not all of the analysis area was necessarily suitable lesser prairie-chicken habitat; they are only the estimated portion of the total analysis area converted from the native vegetation community,
i.e.,
grassland, to cropland. About 37 percent of the total area in the Short-Grass/CRP Ecoregion; 32 percent of the total area in the Sand Sagebrush Ecoregion; 13 percent of the total area in the Mixed-Grass Ecoregion; and 14 percent of the total area in the Shinnery Oak Ecoregion have been converted to cropland in the analysis area of the lesser prairie-chicken. Rangewide, we estimate about 4,963,000 ac (2,009,000 ha) of grassland have been converted to cropland, representing about 23 percent of the total analysis area. We note that these calculations do not account for all conversion that has occurred within the historical range of the lesser prairie-chicken but are limited to the amount of cropland within our analysis area. For further information, including total acreages impacted, see the SSA report for the lesser prairie-chicken (Service 2022, appendix E and figure E.1).

The effects of grassland converted to cropland within the historical range of the lesser prairie-chicken have significantly impacted the amount of habitat available and how fragmented the remaining habitat is for the lesser prairie-chicken, leading to overall decreases in resiliency and redundancy throughout the range of the lesser prairie-chicken. The impact of cropland has shaped the historical and current condition of the grasslands and shrublands upon which the lesser prairie-chicken depends.

Petroleum and Natural Gas Production

Petroleum and natural gas production has occurred over much of the estimated historical and current range of the lesser prairie-chicken. As demand for energy has continued to increase nationwide, so has oil and gas development in the Great Plains. In Texas, for example, one study noted that from 2002-2012 active oil and gas wells in the lesser prairie-chicken occupied range increased by more than 80 percent (Timmer et al. 2014, p. 143). The impacts from oil and gas development extend beyond the immediate well sites; they involve activities such as surface exploration, exploratory drilling, field development, and facility construction, as well as access roads, well pads, and operation and maintenance. Associated facilities can include compressor stations, pumping stations, and electrical generators.

Petroleum and natural gas production result in both direct and indirect habitat effects to the lesser prairie-chicken (Hunt and Best 2004, p. 92). Well pad construction, seismic surveys, access road development, power line construction, pipeline corridors, and other activities can all result in direct habitat loss by removal of vegetation used by lesser prairie-chickens. As documented in other grouse species, indirect habitat loss also occurs from avoidance of vertical structures, noise, and human presence (Weller et al. 2002, entire), which all can influence lesser prairie-chicken behavior in the general vicinity of oil and gas development areas. These activities also disrupt lesser prairie-chicken reproductive behavior (Hunt and Best 2004, p. 41).

Anthropogenic features, such as oil and gas wells, affect the behavior of lesser prairie-chickens and alter the way in which they use the landscape (Hagen et al. 2011, pp. 69-73; Pitman et al. 2005, entire; Hagen 2010, entire; Hunt and Best 2004, pp. 99-104; Plumb et al. 2019, pp. 224-227; Sullins et al. 2019, pp. 5-8; Peterson et al. 2020, entire). Please see the SSA report for a detailed summary of the best available scientific information regarding avoidance distances and effects of oil and gas development on lesser prairie-chicken habitat use (Service 2022, pp. 27-28).

As part of the geospatial analysis discussed in the SSA report, we calculated the amount of usable land cover for the lesser prairie-chicken that has been impacted (both direct and indirect impacts) by oil and natural gas wells in the current analysis area of the lesser prairie-chicken, though this analysis did not include all associated infrastructure as those data were not available. We used an impact radius of 984 feet (ft) (300 meters (m)) for indirect effects of oil and gas wells. For details regarding the establishment of the impact radius, see appendix B, part 2C, of the SSA report (Service 2022). These calculations were limited to the current analysis area and do not include historical impacts of habitat loss that occurred outside of the current analysis area. Thus, the calculation likely underestimates the rangewide effects of historical oil and gas development on the lesser prairie-chicken. About 4 percent of the total area in the Short-Grass/CRP Ecoregion; 5 percent of the total area in the Sand Sagebrush Ecoregion; about 10 percent of the total area in the Mixed-Grass Ecoregion; and 4 percent of the total area in the Shinnery Oak Ecoregion of space that was identified as potential usable or potential restorable areas have been impacted due to oil and gas development in the current analysis area of the lesser prairie-chicken. Rangewide, we estimate about 1,433,000 ac (580,000 ha) of grassland have been lost due to oil and gas development representing about 7 percent of the total analysis area. Maps of these areas in each ecoregion are provided in the SSA report (Service 2022, appendix E, figure E.2).

Oil and gas development directly removes habitat that supports lesser prairie-chicken, and the effects of the development extend past the immediate site of the wells and their associated infrastructure, further impacting habitat and altering behavior of lesser prairie-chicken throughout both the Northern and the Southern DPS. These activities have resulted in decreases in population resiliency and species redundancy.

Wind Energy Development and Power Lines

Wind power is a form of renewable energy increasingly being used to meet current and projected future electricity demands in the United States. Much of the new wind energy development is likely to come from the Great Plains States because they have high wind resource potential, which exerts a strong, positive influence on the amount of wind energy developed within a particular State (Staid and Guikema 2013, p. 384). In 2019, three of the five States within the lesser prairie-chicken range (Colorado, New Mexico, and Kansas) were within the top 10 States nationally for fastest growing States for wind generation in the past year (AWEA 2020, p. 33). There is considerable information (Southwest Power Pool

2020) indicating interest by the wind industry in developing wind energy within the range of the lesser prairie-chicken, especially if additional transmission line capacity is constructed. As of May 2020, approximately 1,792 wind turbines were located within the lesser prairie-chicken analysis area (Hoen et al. 2020). Not all areas within the analysis area are habitat for the lesser prairie-chicken, so not all turbines located within the analysis area affect the lesser prairie-chicken and its habitat.

The average size of installed wind turbines and all other size aspects of wind energy development continues to increase (DOE 2015, p. 63; AWEA 2020, p. 87-88; AWEA 2014, entire; AWEA 2015, entire; AWEA 2016, entire; AWEA 2017, entire; AWEA 2018, entire; AWEA 2019, entire; AWEA 2020, entire). Wind energy developments range from 20 to 400 towers, each supporting a single turbine. The individual permanent footprint of a single turbine unit, about 0.75-1 ac (0.3-0.4 ha), is relatively small in comparison with the overall footprint of the entire array (DOE 2008, pp. 110-111). Roads are necessary to access the turbine sites for installation and maintenance. Depending on the size of the wind energy development, one or more electrical substations, where the generated electricity is collected and transmitted on to the power grid, may also be built. Considering the initial capital investment and that the service life of a single turbine is at least 20 years (DOE 2008, p. 16), we expect most wind energy developments to be in place for at least 30 years. Wind repowering is the combined activity of dismantling or refurbishing existing wind turbines and commissioning new ones at existing wind energy development sites at the end of their service life. Wind repowering is increasingly common, with 2,803 megawatts of operating projects partially repowering in 2019 (AWEA 2020, p. 2).

Please see the SSA report for a detailed review of the best available scientific information regarding the potential effects of wind energy development on habitat use by the lesser prairie-chicken (Service 2022, pp. 29-34).

Noise effects to prairie-chickens have been recently explored as a way to evaluate potential negative effects of wind energy development. For a site in Nebraska, wind turbine noise frequencies were documented at less than or equal to 0.73 kilohertz (kHz) (Raynor et al. 2017, p. 493), and reported to overlap the range of lek-advertisement vocalization frequencies of lesser prairie-chicken, 0.50-1.0 kHz. Female greater prairie-chickens avoided wooded areas and row crops but showed no response in space use based on wind turbine noise (Raynor et al. 2019, entire). Additionally, differences in background noise and signal-to-noise ratio of boom chorus of leks in relation to distance to turbine have been documented, but the underlying cause and response needs to be further investigated, especially since the study of wind energy development noise on grouse is almost unprecedented (Whalen et al. 2019, entire).

The effects of wind energy development on the lesser prairie-chicken must also take into consideration the influence of the transmission lines critical to distribution of the energy generated by wind turbines. Transmission lines can traverse long distances across the landscape and can be both above ground and underground, although the vast majority of transmission lines are erected above ground. Most of the impacts to lesser prairie-chicken associated with transmission lines are with the aboveground systems. Support structures vary in height depending on the size of the line. Most high-voltage power line towers are 98 to 125 ft (30 to 38 m) high but can be higher if the need arises. Local distribution lines, if erected above ground, are usually much shorter in height but still contribute to fragmentation of the landscape.

The effect of the transmission line infrastructure is typically much larger than the physical footprint of transmission line installation. Information on grouse and power lines is relatively limited with more studies needed. The available data includes a range of reported impacts (see Nonne et al. 2013, entire; Dinkins et al. 2014, entire; Hansen et al. 2016, entire; Jarnevich et al. 2016, entire; Londe et al. 2019, entire; LeBeau et al. 2019, entire; Kohl et al. 2019, entire; and England and Robert 2021, entire). Transmission lines can indirectly lead to alterations in lesser prairie-chicken behavior and space use (avoidance), decreased lek attendance, and increased predation on lesser prairie-chicken. Transmission lines, particularly due to their length, can be a significant barrier to dispersal of prairie grouse, disrupting movements to feeding, breeding, and roosting areas. Both lesser and greater prairie-chickens avoided otherwise usable habitat near transmission lines and crossed these power lines much less often than nearby roads, suggesting that power lines are a particularly strong barrier to movement (Pruett et al. 2009, pp. 1255-1257). Because lesser prairie-chicken avoid tall vertical structures like transmission lines and because transmission lines can increase predation rates, leks located in the vicinity of these structures may see reduced attendance by new males to the lek, as has been reported for sage-grouse (Braun et al. 2002, pp. 11-13).

Decreased probabilities of use by lesser prairie-chicken were shown with the occurrence of more than 0.09 mi (0.15 km) of major roads, or transmission lines within a 1.2-mi (2-km) radius (Sullins et al. 2019, unpaged). Additionally, a recent study corroborated numerous authors' (Pitman et al. 2005; Pruett et al. 2009; Hagen et al. 2011; Grisham et al. 2014; Hovick et al. 2014a) findings of negative effects of power lines on prairie grouse and reported a minimum avoidance distance of 1,925.8 ft (587 m), which is similar to other studies of lesser prairie-chickens (Plumb et al. 2019, entire). LeBeau et al. (2020, p. 24) largely aggregated their findings of wind turbines and a transmission line on lesser prairie-chicken into effects of “wind energy infrastructure,” but specifically noted evidence that females selected home ranges farther from transmission lines. Using a definition for transmission powerlines that included powerlines transmitting >69 kilovolts, indicated that taller anthropogenic structures (
i.e.,
transmission powerlines and towers) generally had larger estimated avoidance response distances of all the studied features, but also large regional variation (Peterson et al. 2020, p. 9). They found largest estimated avoidance response of 5.6 mi (9 km) in Northwest Kansas, and the smallest in Oklahoma at approximately 1.8 mi (3 km). Effects from anthropogenic features, including power lines, varied by region, and the degree of effect often depended on the presence of other anthropogenic features (Patten et al. 2021, entire).

As part of our geospatial analysis, we calculated the amount of otherwise usable land cover for the lesser prairie-chicken that has been impacted (both direct and indirect impacts) by wind energy development in the current analysis area of the lesser prairie-chicken. We used an impact radius of 5,906 ft (1,800 m) for indirect effects of wind turbines and 2,297 ft (700 m) for indirect effects of transmission lines. For details regarding the establishment of the impact radius, see appendix B, part 2C, of the SSA report (Service 2022). Within our analysis area, the following acreages have been identified as impacted due to wind energy development: about 2 percent of the total area in the Short-Grass/CRP, Mixed-Grass, and Shinnery Oak Ecoregions; and no impacts of wind

energy development documented currently within the Sand Sagebrush Ecoregion. Rangewide, we estimate about 428,000 ac (173,000 ha) of grassland have been impacted by wind energy development, representing about 2 percent of the total analysis area (Service 2022, appendix E, figure E.3). These percentages do not account for overlap that may exist with other features that may have already impacted the landscape.

Additionally, according to our geospatial analysis, the following acreages within the analysis area have been directly or indirectly impacted due to the construction of transmission lines: about 7 percent of the total area in the Short-Grass/CRP Ecoregion; 5 percent of the total area in the Sand Sagebrush Ecoregion; 7 percent of the total area in the Mixed-Grass Ecoregion; and 10 percent of the total area in the Shinnery Oak Ecoregion. Rangewide, we estimate about 1,553,000 ac (629,000 ha) of grassland have been impacted by transmission lines representing about 7 percent of the total analysis area (Service 2022, appendix E, figure E.4).

Wind energy development and transmission lines remove habitat that supports lesser prairie-chicken. The effects of the development extend past the immediate site of the turbines and their associated infrastructure, further impacting habitat and altering behavior of lesser prairie-chicken throughout both the Northern and the Southern DPSs. These activities have resulted in decreases in population resiliency and species redundancy.

Woody Vegetation Encroachment

As discussed in Background, habitat selected by lesser prairie-chicken is characterized by expansive regions of treeless grasslands interspersed with patches of small shrubs (Giesen 1998, pp. 3-4); lesser prairie-chicken avoid areas with trees and other vertical structures. Prior to extensive Euro-American settlement, frequent fires and grazing by large, native ungulates helped confine trees like eastern red cedar to river and stream drainages and rocky outcroppings. The frequency and intensity of these disturbances directly influenced the ecological processes, biological diversity, and patchiness typical of Great Plains grassland ecosystems (Collins 1992, pp. 2003-2005; Fuhlendorf and Smeins 1999, pp. 732, 737).

Following Euro-American settlement, increasing fire suppression combined with government programs promoting eastern red cedar for windbreaks, erosion control, and wildlife cover facilitated the expansion of eastern red cedar distribution in grassland areas (Owensby et al. 1973, p. 256; DeSantis et al. 2011, p. 1838). Once a grassland area has been colonized by eastern red cedar, the trees are mature within 6 to 7 years and provide a plentiful source of seed so that adjacent areas can readily become infested with eastern red cedar. Despite the relatively short viability of the seeds (typically only one growing season), the large cone crop, potentially large seed dispersal ability, and the physiological adaptations of eastern red cedar to open, relatively dry sites help make the species a successful invader of grassland landscapes (Holthuijzen et al. 1987, p. 1094). Most trees are relatively long-lived and, once they become established in grassland areas, require intensive management to remove to return areas to a grassland state.

Within the southern- and westernmost portions of the estimated historical and occupied ranges of lesser prairie-chicken in Eastern New Mexico, Western Oklahoma, and the South Plains and Panhandle of Texas, honey mesquite is another common woody invader within these grasslands (Riley 1978, p. vii; Boggie et al. 2017, entire). Mesquite is a particularly effective invader in grassland habitat due to its ability to produce abundant, long-lived seeds that can germinate and establish in a variety of soil types and moisture and light regimes (Lautenbach et al. 2017, p. 84). Though not as widespread as mesquite or eastern red cedar, other tall, woody plants, such as redberry or Pinchot juniper (
Juniperus pinchotii
), black locust
(Robinia pseudoacacia
), Russian olive (
Elaeagnus angustifolia
), and Siberian elm (
Ulmus pumila
) can also be found in grassland habitat historically and currently used by lesser prairie-chicken and may become invasive in these areas.

Invasion of grasslands by opportunistic woody species causes otherwise usable grassland habitat no longer to be used by lesser prairie-chicken and contributes to the loss and fragmentation of grassland habitat (Lautenbach 2017, p. 84; Boggie et al. 2017, p. 74). In Kansas, lesser prairie-chicken are 40 times more likely to use areas that had no trees than areas with 1.6 trees per ac (5 trees per ha), and no nests occur in areas with a tree density greater than 0.8 trees per ac (2 trees per ha), at a scale of 89 ac (36 ha) (Lautenbach 2017, pp. 104-142). Similarly, within the Shinnery Oak Ecoregion, lesser prairie-chicken habitat use in all seasons is altered in the presence of mesquite, even at densities of less than 5 percent canopy cover (Boggie et al. 2017, entire). Woody vegetation encroachment also contributes to indirect habitat loss and increases habitat fragmentation because lesser prairie-chicken are less likely to use areas adjacent to trees (Boggie et al. 2017, pp. 72-74; Lautenbach 2017, pp. 104-142).

Fire is often the best method to control or preclude tree invasion of grassland. However, to some landowners and land managers, burning of grassland can be perceived as a high-risk activity because of the potential liability of escaped fire impacting nontarget lands and property. Additionally, it is undesirable for optimizing cattle production and is likely to create wind erosion or “blowouts” in sandy soils. Consequently, wildfire suppression is common, and relatively little prescribed burning occurs on private land. Often, prescribed fire is employed only after significant tree invasion has already occurred and landowners consider forage production for cattle to have diminished. Preclusion of woody vegetation encroachment on grasslands of the southern Great Plains using fire requires implementing fire at a frequency that mimics historical fire frequencies of 2-14 years (Guyette et al. 2012, p. 330), further limiting the number of landowners able to implement fire in a manner that would truly preclude future encroachment. Additionally, in areas where grazing pressure is heavy and fuel loads are reduced, a typical grassland fire may not be intense enough to eradicate eastern red cedar (Briggs et al. 2002a, p. 585; Briggs et al. 2002b, p. 293; Bragg and Hulbert 1976, p. 19) and will not eradicate mesquite.

As part of our geospatial analysis, we calculated the amount of woody vegetation encroachment in the current analysis area of the lesser prairie-chicken. These calculations of the current analysis area do not include historical impacts of habitat loss that occurred outside of the current analysis area; thus, it likely underestimates the effects of historical woody vegetation encroachment rangewide on the lesser prairie-chicken. An additional limitation associated with this calculation is that available remote sensing data lack the ability to detect areas with low densities of encroachment, as well as areas with shorter trees; thus, this calculation likely underestimates lesser prairie-chicken habitat loss due to woody vegetation encroachment. The identified areas of habitat impacted by woody vegetation are: about 5 percent of the total area in the Short-Grass/CRP Ecoregion; about 2 percent of the total area in the Sand Sagebrush Ecoregion;

about 24 percent of the total area in the Mixed-Grass Ecoregion; and about 17 percent of the total area in the Shinnery Oak Ecoregion. Rangewide, we estimate about 3,071,000 ac (1,243,000 ha) of grassland have been directly or indirectly impacted by the encroachment of woody vegetation, or about 18 percent of the total area. These percentages do not account for overlap that may exist with other features that may have already impacted the landscape. Further information, including total acres impacted, is available in the SSA report (Service 2022, appendix B; appendix E, figure E.5).

Woody vegetation encroachment is contributing to ongoing habitat loss as well as contributing to fragmentation and degradation of remaining habitat patches. The effects of woody vegetation encroachment are particularly widespread in the Shinnery Oak Ecoregion that makes up the Southern DPS as well as the Mixed-Grass Ecoregion of the Northern DPS. While there are ongoing efforts to control woody vegetation encroachment, the current level of woody vegetation on the landscape is evidence that removal efforts are being outpaced by rates of encroachment; thus, we expect that this threat will continue to contribute to habitat loss and fragmentation, which has reduced population resiliency across the range of the lesser prairie-chicken.

Roads and Electrical Distribution Lines

Roads and distribution power lines are linear features on the landscape that contribute to loss and fragmentation of lesser prairie-chicken habitat and fragment populations as a result of behavioral avoidance. Lesser prairie-chickens are less likely to use areas close to roads (Plumb et al. 2019, entire; Sullins et al. 2019, entire). Additionally, roads contribute to lek abandonment when they disrupt important habitat features (such as affecting auditory or visual communication) associated with lek sites (Crawford and Bolen 1976b, p. 239). Some mammal species that prey on lesser prairie-chicken, such as red fox (
Vulpes vulpes
), raccoons (
Procyon lotor
), and striped skunks (
Mephitis mephitis
), have greatly increased their distribution by dispersing along roads (Forman and Alexander 1998, p. 212; Forman 2000, p. 33; Frey and Conover 2006, pp. 1114-1115).

Traffic noise from roads may indirectly impact lesser prairie-chicken. Because lesser prairie-chicken depend on acoustical signals to attract females to leks, noise from roads, oil and gas development, wind turbines, and similar human activity may interfere with mating displays, influencing female attendance at lek sites and causing young males not to be drawn to the leks. Within a relatively short period, leks can become inactive due to a lack of recruitment of new males to the display grounds. For further discussion on noise, please see
Influence of Anthropogenic Noise.

Depending on the traffic volume and associated disturbances, roads also may limit lesser prairie-chicken dispersal abilities. Lesser prairie-chickens avoid areas of usable habitat near roads (Pruett et al. 2009, pp. 1256, 1258; Plumb et al. 2019, entire) and in areas where road densities are high (Sullins et al. 2019, p. 8). Lesser prairie-chickens are thought to avoid major roads due to disturbance caused by traffic volume and perhaps to avoid exposure to predators that may use roads as travel corridors. However, the extent to which roads constitute a significant obstacle to lesser prairie-chicken movement and space use is largely dependent upon the local landscape composition and characteristics of the road itself.

Local electrical distribution lines are usually much shorter in height than transmission lines but can still contribute to habitat fragmentation through similar mechanisms as other vertical features when erected above ground. In addition to habitat loss and fragmentation, electrical power lines can directly affect prairie grouse by posing a collision hazard (Leopold 1933, p. 353; Connelly et al. 2000, p. 974). There were no datasets available to quantify the total impact of distribution lines on the landscape for the lesser prairie-chicken. Although distribution lines are a significant landscape feature throughout the Great Plains with potential to affect lesser prairie-chicken habitat, after reviewing all available information, we were unable to develop a method to quantitatively incorporate the occurrence of distribution lines into our geospatial analysis.

As part of our geospatial analysis, we estimated the area impacted by direct and indirect habitat loss due to roads (Service 2022, appendix B, part 2). These calculations of the current analysis area do not include historical impacts of loss; thus, the calculations likely underestimate the historical effect of roads on rangewide habitat loss for the lesser prairie-chicken. The results indicate that the total areas of grassland that have been directly and indirectly impacted by roads within the analysis area for the lesser prairie-chicken are: about 17 percent of the total area in the Short-Grass/CRP Ecoregion; about 14 percent of the total area in the Sand Sagebrush Ecoregion; about 20 percent of the total area in the Mixed-Grass Ecoregion; and about 19 percent of the total area in the Shinnery Oak Ecoregion. Rangewide, we estimate about 3,996,000 ac (1,617,000 ha) of grassland have been impacted by roads, representing about 18 percent of the total analysis area (Service 2022, appendix E, figure E.6). We did not have adequate spatial data to evaluate habitat loss caused solely by electrical distribution lines, but much of the existing impacts of power lines occur within the impacts caused by roads. Electrical distribution lines that fall outside the existing impacts of roads would represent additional impacts for the lesser prairie-chicken that are not quantified in our geospatial analysis.

Development of roads and electrical distribution lines directly removes habitat that supports lesser prairie-chicken, and the effects of the development extend past the immediate footprint of the development, further impacting habitat and altering behavior of lesser prairie-chicken throughout both the Northern and the Southern DPSs. These activities have resulted in decreases in population resiliency and species redundancy.

Other Factors

Livestock Grazing

Grazing has long been an ecological driving force throughout the ecosystems of the Great Plains (Stebbins 1981, p. 84), and much of the untilled grasslands within the range of the lesser prairie-chicken is currently grazed by livestock and other animals. Historically, the interaction of fire, drought, prairie dogs (
Cynomys ludovicianus
), and large ungulate grazers created and maintained distinctive plant communities in the Western Great Plains, resulting in a mosaic of vegetation structure and composition that sustained lesser prairie-chicken and other grassland bird populations (Derner et al. 2009, p. 112). As such, grazing by domestic livestock is not inherently detrimental to lesser prairie-chicken management and, in many cases, is needed to maintain appropriate vegetative structure.

However, grazing practices that tend to result in overutilization of forage and decreasing vegetation heterogeneity can produce habitat conditions that differ in significant ways from the historical grassland mosaic; these incompatible practices alter the vegetation structure and composition and degrade the quality of habitat for the lesser prairie-chicken. The more heavily altered conditions are the least valuable for the lesser prairie-chicken (Jackson and

DeArment 1963 p. 733; Davis et al. 1979, pp. 56, 116; Taylor and Guthery 1980a, p. 2; Bidwell and Peoples 1991, pp. 1-2). In some cases, these alterations can result in areas that do not contain the biological components necessary to support the lesser prairie-chicken.

Where grazing regimes leave limited residual cover in the spring, protection of lesser prairie-chicken nests may be inadequate, and desirable food resources can be scarce (Bent 1932, p. 280; Cannon and Knopf 1980, pp. 73-74; Crawford 1980, p. 3; Kraft 2016, pp. 19-21). Because lesser prairie-chicken depend on medium- and tall-grass species for nesting, concealment, and thermal cover that are also preferentially grazed by cattle, these plant species needed by lesser prairie-chicken can easily be reduced or eliminated by cattle grazing, particularly in regions of low rainfall (Hamerstrom and Hamerstrom 1961, p. 290). In addition, when grasslands are in a deteriorated condition due to incompatible grazing and overutilization, the soils have less water-holding capacity (Blanco and Lal 2010, p. 9), and the availability of succulent vegetation and insects used by lesser prairie-chicken chicks is reduced. However, grazing can be beneficial to the lesser prairie-chicken when management practices produce or enhance the vegetative characteristics required by the lesser prairie-chicken.

The interaction of fire and grazing and its effect on vegetation components and structure is likely important to prairie-chickens (Starns et al. 2020, entire). On properties managed with patch-burn grazing regimes, female greater prairie-chickens selected areas with low cattle stocking rates and patches that were frequently burned, though they avoided areas that were recently burned (Winder et al. 2017, p. 171). Patch-burn grazing created preferred habitats for female greater prairie-chickens if the regime included a relatively frequent fire-return interval, a mosaic of burned and unburned patches, and a reduced stocking rate in unburned areas avoided by grazers. When managed compatibly, widespread implementation of patch-burn grazing could result in significant improvements in habitat quality for wildlife in the tall-grass prairie ecosystem (Winder et al. 2017, p. 165). In the eastern portion of the lesser prairie-chicken range, patch-burn grazing resulted in patchy landscapes with variation in vegetation composition and structure (Lautenbach 2017, p. 20). Female lesser prairie-chickens' use of the diversity of patches in the landscape varied throughout their life cycle. They selected patches with the greatest time-since-fire and subsequently the most visual obstruction for nesting, and they selected sites with less time-since-fire and greater bare ground and forbs for summer brooding.

Livestock also inadvertently flush lesser prairie-chicken and trample lesser prairie-chicken nests (Toole 2005, p. 27; Pitman et al. 2006, pp. 27-29). Brief flushing of adults from nests can expose eggs and chicks to predation and extreme temperatures. Trampling nests can cause direct mortality to lesser prairie-chicken eggs or chicks or may cause adults to permanently abandon their nests, ultimately resulting in loss of young. Although these effects have been documented, the significance of direct livestock effects on the lesser prairie-chicken is largely unknown and is presumed not to be significant at a population scale.

In summary, domestic livestock grazing (including management practices commonly used to benefit livestock production) has altered the composition and structure of grassland habitat, both currently and historically, used by the lesser prairie-chicken. Much of the remaining remnants of mixed-grass grasslands, while still important to the lesser prairie-chicken, exhibit conditions quite different from those prior to Euro-American settlement. These changes have reduced the suitability of remnant grassland areas as habitat for lesser prairie-chicken. Grazing management that has altered the vegetation community to a point where the composition and structure are no longer suitable for lesser prairie-chicken can contribute to fragmentation within the landscape, even though these areas may remain as prairie or grassland. Livestock grazing, however, is not inherently detrimental to lesser prairie-chicken provided that grazing management results in a plant community diversity and structure that is suitable for lesser prairie-chicken.

While domestic livestock grazing is a dominant land use on untilled range land within the lesser prairie-chicken analysis area, geospatial data do not exist at a scale and resolution necessary to calculate the total amount of livestock grazing that is being managed in a way that results in habitat conditions that are not compatible with the needs of the lesser prairie-chicken. Therefore, we did not attempt to spatially quantify the scope of grazing effects across the lesser prairie-chicken range.

Shrub Control and Eradication

Shrub control and eradication are additional forms of habitat alteration that can influence the availability and suitability of habitat for lesser prairie-chicken (Jackson and DeArment 1963, pp. 736-737). Most shrub control and eradication efforts in lesser prairie-chicken habitat are primarily focused on sand shinnery oak for the purpose of increasing forage for livestock grazing. Sand shinnery oak is toxic if eaten by cattle when it first produces leaves in the spring and competes with more palatable grasses and forbs for water and nutrients (Peterson and Boyd 1998, p. 8), which is why it is a common target for control and eradication efforts by rangeland managers. Prior to the late 1990s, approximately 100,000 ac (40,000 ha) of sand shinnery oak in New Mexico and approximately 1,000,000 ac (405,000 ha) of sand shinnery oak in Texas were lost due to the application of tebuthiuron and other herbicides for agriculture and range improvement (Peterson and Boyd 1998, p. 2).

Shrub cover is an important component of lesser prairie-chicken habitat in certain portions of the range, and sand shinnery oak is a key shrub in the Shinnery Oak and portions of the Mixed-Grass Ecoregions. The importance of sand shinnery oak as a component of lesser prairie-chicken habitat in the Shinnery Oak Ecoregion has been demonstrated by several studies (Fuhlendorf et al. 2002, pp. 624-626; Bell 2005, pp. 15, 19-25). In West Texas and New Mexico, lesser prairie-chicken avoid nesting where sand shinnery oak has been controlled with tebuthiuron, indicating their preference for habitat with a sand shinnery oak component (Grisham et al. 2014, p. 18; Haukos and Smith 1989, p. 625; Johnson et al. 2004, pp. 338-342; Patten and Kelly 2010, p. 2151). Where sand shinnery oak occurs, lesser prairie-chicken use it both for food and cover. Sand shinnery oak may be particularly important in drier portions of the range that experience more severe and frequent droughts and extreme heat events, as sand shinnery oak is more resistant to drought and heat conditions than are most grass species. And because sand shinnery oak is toxic to cattle and thus not targeted by grazing, it can provide available cover for lesser prairie-chicken nesting and brood rearing during these extreme weather events. Loss of this component of the vegetative community likely contributed to observed population declines in lesser prairie-chicken in these areas.

While relatively wide-scale shrub eradication has occurred in the past, geospatial data do not exist to evaluate the extent to which shrub eradication has contributed to the habitat loss and fragmentation for the lesser prairie-chicken and, therefore, was not included in our quantitative analysis.

While current efforts of shrub eradication are not likely occurring at rates equivalent to those witnessed in the past, any additional efforts to eradicate shrubs that are essential to lesser prairie-chicken habitat will result in additional habitat degradation and thus reduce redundancy and resiliency.

Influence of Anthropogenic Noise

Anthropogenic noise can be associated with almost any form of human activity, and lesser prairie-chicken may exhibit behavioral and physiological responses to the presence of noise. In prairie-chickens, the “boom” call vocalization transmits information about sex, territorial status, mating condition, location, and individual identity of the signaler and thus is important to courtship activity and long-range advertisement of the display ground (Sparling 1981, p. 484). The timing of displays and frequency of vocalizations are critical reproductive behaviors in prairie grouse and appear to have developed in response to unobstructed conditions prevalent in prairie habitat and indicate that effective communication, particularly during the lekking season, operates within a fairly narrow set of acoustic conditions. Prairie grouse usually initiate displays on the lekking grounds around sunrise, and occasionally near sunset, corresponding with times of decreased wind turbulence and thermal variation (Sparling 1983, p. 41). Considering the narrow set of acoustic conditions in which communication appears most effective for breeding lesser prairie-chicken and the importance of communication to successful reproduction, human activities that result in noises that disrupt or alter these conditions could result in lek abandonment (Crawford and Bolen 1976b, p. 239). Anthropogenic features and related activities that occur on the landscape can create noise that exceeds the natural background or ambient level. When the behavioral response to noise is avoidance, as it often is for lesser prairie-chicken, noise can be a source of habitat loss or degradation leading to increased habitat fragmentation.

Anthropogenic noise may be a possible factor in the population declines of other species of lekking grouse in North America, particularly for populations that are exposed to human developments (Blickley et al. 2012a, p. 470; Lipp and Gregory 2018, pp. 369-370). Male greater prairie-chicken adjust aspects of their vocalizations in response to wind turbine noise, and wind turbine noise may have the potential to mask the greater prairie-chicken chorus at 296 hertz (Hz) under certain scenarios, but the extent and degree of masking is uncertain (Whalen 2015, entire). Noise produced by typical oil and gas infrastructure can mask grouse vocalizations, compromise the ability of female sage-grouse to find active leks when such noise is present, and affect nest site selection (Blickley and Patricelli 2012, p. 32; Lipp 2016, p. 40). Chronic noise associated with human activity leads to reduced male and female attendance at noisy leks. Breeding, reproductive success, and ultimately recruitment in areas with human developments could be impaired by such developments, impacting survival (Blickley et al. 2012b, entire). Because opportunities for effective communication on the display ground occur under fairly narrow conditions, disturbance during this period may have negative consequences for reproductive success. Other communications used by grouse off the lek, such as parent-offspring communication, may continue to be susceptible to masking by noise from human infrastructure (Blickley and Patricelli 2012, p. 33).

No data are available to quantify the areas of lesser prairie-chicken habitat rangewide that have been affected by noise, but noise is a threat that is almost entirely associated with anthropogenic features such as roads or energy development. Therefore, through our accounting for anthropogenic features we may have inherently accounted for all or some of the response of the lesser prairie-chicken to noise produced by those features.

Overall, persistent anthropogenic noise could cause lek attendance to decline, disrupt courtship and breeding activity, and reduce reproductive success. Noise can also cause abandonment of otherwise usable habitat and, as a result, contribute to habitat loss and degradation.

Fire

Fire, or its absence, is understood to be a major ecological driver of grasslands in the Southern Great Plains (Anderson 2006, entire; Koerner and Collins 2014, entire; Wright and Bailey 1982, pp. 80-137). Fire is an ecological process important to maintaining grasslands by itself and in coupled interaction with grazing and climate. The interaction of these ecological processes results in increasing grassland heterogeneity through the creation of temporal and spatial diversity in plant community composition and structure and associated response of wildlife (Fuhlendorf and Engle 2001, entire; Fuhlendorf and Engle 2004, entire; Fuhlendorf et al. 2017a, pp. 169-196).

Following settlement of the Great Plains, fire management generally emphasized prevention and suppression, often coupled with grazing pressures that significantly reduced and removed fine fuels (Sayre 2017, pp. 61-70). This approach, occurring in concert with settlement and ownership patterns that occurred in most of the Southern Great Plains, meant that the scale of management was relegated to smaller parcels than historically were affected. This increase in smaller parcels with both intensive grazing and fire suppression resulted in the transformation of landscapes from dynamic heterogeneous to largely static and homogenous plant communi

[Text truncated at 120,000 characters. The full text is on the page linked above.]

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2022-25214. Public record. Not legal advice.