Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To Delist the Coastal California Gnatcatcher, 59952-59975 [2016-20864]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 81, Number 169 (Wednesday, August 31, 2016)]
[Proposed Rules]
[Pages 59952-59975]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-20864]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2014-0058; FXES11130900000C2-167-FF09E42000]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To Delist the Coastal California Gnatcatcher

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to remove the coastal California 
gnatcatcher (Polioptila californica californica) from the Federal List 
of Endangered and Threatened Wildlife (List) under the Endangered 
Species Act of 1973, as amended. After review of the best available 
scientific and commercial information, we find that delisting the 
coastal California gnatcatcher is not warranted at this time.

DATES: The finding announced in this document was made on August 31, 
2016.

ADDRESSES: This finding, as well as supporting documentation we used in 
preparing this finding, is available on the Internet at https://www.regulations.gov at Docket Number FWS-R8-ES-2014-0058. Supporting 
documentation we used in preparing this finding will also be available 
for public inspection, by appointment, during normal business hours at 
the U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 
2177 Salk Avenue, Suite 250, Carlsbad, CA 92008. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above address.

FOR FURTHER INFORMATION CONTACT: G. Mendel Stewart, Field Supervisor, 
Carlsbad Fish and Wildlife Office, 2177 Salk Avenue, Suite 250, 
Carlsbad, CA 92008; by telephone at 760-431-9440; or by facsimile at 
760-431-5901. If you use a telecommunications device for the deaf 
(TDD), please call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    Under the Endangered Species Act of 1973, as amended (ESA or Act; 
16 U.S.C. 1531 et seq.), we administer the Federal Lists of Endangered 
and Threatened Wildlife and Plants, which are set forth in title 50 of 
the Code of Federal Regulations in part 17 (50 CFR 17.11 and 17.12). 
Under section 4(b)(3)(B) of the Act, for any petition that we receive 
to revise either List by adding, removing, or reclassifying a species, 
we must make a finding within 12 months of the date of receipt if the 
petition contains substantial scientific or commercial information 
supporting the requested action. In this finding, we will determine 
that the petitioned action is: (1) Not warranted; (2) warranted; or (3) 
warranted, but the immediate proposal of a regulation is precluded by 
other pending proposals to determine whether any species are endangered 
species or threatened species and expeditious progress is being made to 
add or remove qualified species from the Lists. Section 4(b)(3)(C) of 
the Act requires that we treat a petition for which the requested 
action is found to be warranted but precluded as though

[[Page 59953]]

resubmitted on the date of such finding, that is, requiring a 
subsequent finding to be made within 12 months. We must publish these 
12-month findings in the Federal Register.

Previous Federal Actions

    Since the coastal California gnatcatcher was first identified as a 
category 2 candidate species in 1982, it has been the subject of 
numerous Federal Register publications. We published a final rule to 
list Polioptila californica californica as a threatened species under 
the Act on March 30, 1993 (58 FR 16742), and we affirmed that 
determination in 1995 (60 FR 15693; March 27, 1995). Critical habitat 
for the subspecies was first established via a final rule that 
published on October 24, 2000 (65 FR 63680), and a revised final 
critical habitat rule was published on December 19, 2007 (72 FR 72010). 
The most recent Federal action prior to 2014 was our 2011 90-day 
finding on a petition to delist the coastal California gnatcatcher (76 
FR 66255; October 26, 2011). We concluded at that time that the 
petition did not present substantial scientific or commercial 
information to indicate that delisting the coastal California 
gnatcatcher may be warranted (76 FR 66255; October 26, 2011). A summary 
of all previous Federal actions can be found at https://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=B08X.

Species Information

    The coastal California gnatcatcher (Polioptila californica 
californica) is a member of the avian family Polioptilidae (Chesser et 
al. 2010, p. 736). The bird's plumage is dark blue-gray above and 
grayish-white below. The tail is mostly black above and below. The male 
has a distinctive black cap, which is absent during the winter. Both 
sexes have a distinctive white eye-ring. This subspecies occurs 
primarily in or near vegetation categorized as coastal scrub, including 
coastal sage scrub. This vegetation is typified by low (less than 3 
feet (ft) (1 meter (m)), shrub, and sub-shrub species that are often 
drought-deciduous (O'Leary 1990, p. 24; Holland and Keil 1995, p. 163; 
Rubinoff 2001, p. 1,376). Within the United States, the subspecies is 
restricted to coastal southern California from Ventura and San 
Bernardino Counties, south to the Mexican border. Within Mexico, its 
range extends from the U.S.-Mexico border into coastal Baja California 
south to approximately El Rosario, Mexico, at about 30 degrees north 
latitude (Grinnell 1926, p. 499; AOU 1957, p. 451; Miller et al. 1957, 
p. 204; Atwood 1991, p. 127; Phillips 1991, pp. 25-26; Atwood and 
Bontrager 2001, p. 3).
    In our 2010 5-year review, we reported an estimate of 1,324 
gnatcatcher pairs over an 111,006-acre (ac) (44,923-hectare (ha)) area 
on lands owned by city, county, State, and Federal agencies (public and 
quasi-public lands) of Orange and San Diego Counties (Service 2010, p. 
8). We indicated that this study sampled only a portion of the U.S. 
range of the subspecies (the coastal regions), and that it was limited 
to 1 year (Winchell and Doherty 2008, p. 1,324). Standardized, 
rangewide population trends and occupancy estimates for the coastal 
California gnatcatcher (within the United States or Mexico) are not 
available at this time given the limited and incomplete survey 
information as well as the variability in the survey methods and 
reporting.
    Since the publication of the 2010 5-year review, we have received 
the following results from limited surveys of the coastal California 
gnatcatcher within the U.S. portion of the range:
    (1) 25 nests (with 11 successes out of 29 nesting attempts) within 
the Western Riverside County Multi-Species Habitat Conservation Plan 
(Western Riverside County MSHCP) for the year 2014 in eight of the 
plan's designated core areas (Biological Monitoring Program 2015, p. 
8);
    (2) 122 pairs and 33 single males (155 territories) within the City 
of Carlsbad (under the San Diego County Multiple Habitat Conservation 
Plan (San Diego County MHCP) in 2013, an increase of 28 territories 
from 2010 despite little change in survey area (City of Carlsbad 2013, 
p. 2);
    (3) for Orange County, 12.7 percent occupancy within the Central 
Reserve and 34.3 percent occupancy in the Coastal Reserve (plus 17 
other incidental observations) (Leatherman Bioconsulting 2012, p. 5); 
and
    (4) 436 occupied sites for the coastal California gnatcatcher on 
Marine Corps Base Camp Pendleton (Camp Pendleton) (San Diego County) in 
2014, including 122 territorial males, 283 pairs, and 31 family groups, 
with an additional 53 transient individuals identified (Tetra Tech 
2015, p. ii). We will continue to work with our partners to gather data 
on coastal California gnatcatcher populations and trends.
    Since listing, we have updated information regarding the range of 
the subspecies. In our 2010 5-year review (Service 2010, pp. 6, 8; 
Table 1), we presented our estimate of the existing range of the 
coastal California gnatcatcher at that time. We also updated the extent 
of the subspecies' range in Baja California, Mexico, using the coastal 
sage scrub vegetation map prepared by Rebman and Roberts (2012, p. 22) 
and observations of California gnatcatchers (all subspecies of 
Polioptila californica) (in Baja California (www.ebird.org; accessed 
December 15, 2015). This information is combined in the range map shown 
in Figure 1. We currently estimate 56 percent of the range is in the 
United States and 44 percent of the range is in Baja California, 
Mexico.
    For additional information on the general biology and life history 
of the coastal California gnatcatcher, please see our most recent 5-
year status review (Service 2010), available at the following Web 
sites: https://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=B08X and https://www.fws.gov/carlsbad/.
BILLING CODE 4310-55-P

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[GRAPHIC] [TIFF OMITTED] TP31AU16.000

BILLING CODE 4310-55-C

Petition History

    On May 29, 2014, we received a combined petition from the Center 
for Environmental Science, Accuracy, and Reliability; Coalition of 
Labor, Agriculture and Business; Property Owners Association of 
Riverside County; National Association of Home

[[Page 59955]]

Builders; and the California Building Industry Association 
(collectively, petitioners), requesting that the coastal California 
gnatcatcher be removed from the Federal List of Endangered and 
Threatened Wildlife (List) under the Act. The petition clearly 
identified itself as such and included the requisite identification 
information for the petitioners, as required in 50 CFR 424.14(a).
    The factors for listing, delisting, or reclassifying species are 
described at 50 CFR 424.11. We may delist a species only if the best 
scientific and commercial data available substantiate that it is 
neither endangered nor threatened. Delisting may be warranted as a 
result of: (1) Extinction; (2) recovery; or (3) a determination that 
the original scientific data used at the time the species was listed, 
or interpretation of that data, were in error.
    The petition did not assert that the coastal California gnatcatcher 
is extinct, nor do we have information in our files indicating that the 
coastal California gnatcatcher is extinct. The petition did not assert 
that the coastal California gnatcatcher has recovered and is no longer 
an endangered species or threatened species, nor do we have information 
in our files indicating the coastal California gnatcatcher has 
recovered (further detail on the status of the coastal California 
gnatcatcher is presented in the Summary of the Five Factors section 
below). The petition also did not contain any information regarding 
threats to the coastal California gnatcatcher.
    The petition asserts that the original scientific data used at the 
time the species was classified were in error and that the best 
available scientific data show no support for the taxonomic recognition 
of the coastal California gnatcatcher as a distinguishable subspecies 
(Thornton and Schiff 2014, p. 1). The petition's assertions are 
primarily based on the results of genetic and ecological analyses 
published in Zink et al. (2013). The petition maintains that, based on 
this new information, the Service cannot continue to rely on 
morphological measurements to determine whether the coastal California 
gnatcatcher is a valid (distinguishable) subspecies (Thornton and 
Schiff 2014, pp. 31-32).
    The petition asserts that the morphological information originally 
used to distinguish the subspecies is flawed, citing published and 
unpublished critiques, alternative analyses, and other interpretations 
of morphological characteristics of California gnatcatchers (Thornton 
and Schiff 2014, pp. 14-21). The petition also contends that available 
genetic data do not support the coastal California gnatcatcher as a 
distinguishable subspecies (Thornton and Schiff 2014, p. 28). As 
evidence, the petition cites two published scientific articles in 
particular, Zink et al. (2000) and Zink et al. (2013), which were 
included as part of the petition. The petition asserts that these two 
studies ``constitute the best available scientific data'' (Thornton and 
Schiff 2014, p. 28) regarding the subspecific status of the coastal 
California gnatcatcher.
    The petition discusses the results of both Zink et al. (2000) and 
Zink et al. (2013). Zink et al. (2000) examined variation within the 
mitochondrial DNA (mtDNA) control region and three mtDNA genes of the 
California gnatcatcher species as a whole and concluded that the 
genetic information did not support recognition of infraspecific taxa 
(subspecies) in the California gnatcatcher, including the coastal 
California gnatcatcher subspecies (Thornton and Schiff 2014, pp. 20-
23). The petition further asserts that the genetic analysis presented 
in Zink et al. (2013, entire), based on eight different nuclear markers 
or loci and a reduced data set from Zink et al. (2000, entire), did not 
identify geographic groupings that corresponded with any previously 
recognized subspecies (Thornton and Schiff 2014, p. 28). The petition 
states that the nuclear DNA analysis in Zink et al. (2013) is 
consistent with a conclusion that the range of the California 
gnatcatcher has recently expanded from southern Baja California and 
that the species ``is not divisible into discrete, listable units'' 
(Thornton and Schiff 2014, p. 29).
    The petition also provides results from an ecological niche model 
from Zink et al. (2013, pp. 453-454). The study presented results from 
niche divergence models constructed for California gnatcatchers 
represented in mesic coastal sage scrub (``northern population'') 
versus southern populations. The petition asserts that the model 
results indicate that the two groups do not exhibit significant niche 
divergence if the backgrounds of each environment are taken into 
account; it further states that the results from the ecological niche 
model support the petition's assertions that there is no valid 
taxonomic subdivision of the California gnatcatcher (Thornton and 
Schiff 2014, pp. 29-30). The petition concludes that the best available 
data indicate that the California gnatcatcher (the species as a whole) 
``is not divisible into discrete, listable units, but instead is a 
single historical entity throughout its geographic range'' (Thornton 
and Schiff 2014, p. 32).
    On December 31, 2014, we published in the Federal Register a 90-day 
finding (79 FR 78775) that the petition presented substantial 
information indicating that delisting may be warranted. With 
publication of the finding, we initiated a review of the status of the 
subspecies. We requested further information from the public on issues 
related to the coastal California gnatcatcher such as: Taxonomy; 
biology; new morphological or genetic information; consideration of the 
coastal California gnatcatcher as a distinct population segment (DPS); 
and information on the methods, results, and conclusions of Zink et al. 
(2000; 2013). In our status review below, we first examine whether the 
coastal California gnatcatcher is a valid subspecies, and thus a 
``species'' as defined in section 3 of the Act. According to section 
3(16) of the Act, we may list any of three categories of vertebrate 
animals: A species, subspecies, or a distinct population segment of a 
vertebrate species of wildlife. We refer to each of these categories as 
a ``listable entity.'' If we determine that there is a species, or 
``listable entity,'' for the purposes of the Act, our status review 
next evaluates whether the species meets the definitions of an 
``endangered species'' or a ``threatened species'' because of any of 
the five listing factors established under section 4(a)(1) of the Act.
    In response to our information request associated with the status 
review of the subspecies, we received more than 39,000 letters. Most 
responders submitted form letters that opposed delisting of the coastal 
California gnatcatcher. Some submitted additional reports and 
references for our consideration. New information submitted included 
survey and trend data for localized areas, information related to 
effectiveness of regulatory mechanisms, information on restoration 
efforts, and information on threats to the subspecies and its habitat 
in the United States and in Mexico.
    Additionally, multiple parties submitted critical analyses of 
information presented in the petition and in Zink et al. (2013), 
including a then ``in press'' (prepublication) scientific paper that 
was subsequently published in the journal The Auk: Ornithological 
Advances (McCormack and Maley 2015) that disputed the methods and 
results presented in Zink et al. (2013). We received several responses 
from members of the scientific community, many of which provided 
critiques of the methods and

[[Page 59956]]

interpretations of Zink et al. (2013), including critiques of the 
statistical analyses of the information presented, the selection and 
number of loci used in the genetic analyses, the methods and 
interpretation of the niche model, and the conclusion by Zink et al. 
(2013) that a lack of detection of genetic structure necessarily meant 
a lack of taxonomic distinctiveness (Andersen 2015, pers. comm.; Cicero 
2015, pers. comm.; Fallon 2015, pers. comm.; Patten 2015, pers. comm.). 
We also received reanalyses of the genetic data used by Zink et al. 
(2013) (Andersen 2015, pers. comm.; McCormack and Maley 2015).
    One commenter expressed support for the petition's arguments and 
the conclusions reached by Zink et al. (2013) and dismissed the 
findings of McCormack and Maley (2015) (Ramey 2015, pers. comm.). We 
received two responses from Zink dated March 2, 2015, and June 8, 2015 
(Zink 2015a, pers. comm.; Zink 2015b, pers. comm.), and we received a 
response from one of the petitioners dated March 2, 2015 (Thornton 
2015, pers. comm.), that directly addressed the critiques submitted by 
many of the other responders. These additional responses and additional 
supporting materials are available on the Internet at https://www.regulations.gov at Docket Number FWS-R8-ES-2014-0058.
    Given the diverse and conflicting information submitted by the 
public and members of the scientific community in response to our 
request for information (79 FR 78775; December 31, 2014), we convened a 
scientific review panel. Through a Science Advisory Services contract 
process, the Service contracted Amec Foster Wheeler Infrastructure and 
Environment, Inc. (hereafter Amec Foster Wheeler) to assemble a panel 
of independent experts to provide individual input on the available 
data concerning the subspecies designation of the coastal California 
gnatcatcher. Amec Foster Wheeler selected six panelists in accordance 
with peer review and scientific integrity guidelines from the Office of 
Management and Budget's Final Information Quality Bulletin (OMB 2004). 
The selected panelists each had between 19 and 35 years of experience 
in their respective fields, which included avian conservation, 
conservation genetics, taxonomy, population genetics, and systematics. 
An experienced facilitator with expertise in genetics and genetic 
techniques was also selected by Amec Foster Wheeler to assist and guide 
the panelists in their discussions during a 2-day workshop. Additional 
details regarding the selection of the panelists and their 
qualifications are available in the Final Workshop Review Report for 
the California Gnatcatcher Facilitated Science Panel Workshop 
(hereafter ``science panel report'') (Amec 2015, pp. 2-3, and Appendix 
D). This report is available as a supporting document we used in 
preparing this finding on the Internet at https://www.regulations.gov at 
Docket Number FWS-R8-ES-2014-0058. Conflict of interest forms were 
submitted by each panelist. The Service was not involved in any portion 
of the selection process, nor were we aware of the panelists' 
identities prior to the workshop.
    Prior to the workshop, the Service prepared a list of relevant 
literature and Federal Register documents related to the science and 
listing history of the coastal California gnatcatcher. The panelists 
requested that we provide summaries of the subspecies' listing history, 
taxonomy, the Service's listable entity and DPS policies, and a summary 
of public comments. All documents were relayed to the panelists through 
the Amec Foster Wheeler Project Manager. A complete list of information 
and references provided is available in the workshop science panel 
report (Amec 2015, Appendix B).
    The workshop was held at the Carlsbad Fish and Wildlife Office on 
August 17-18, 2015. The purpose of the workshop was to provide a forum 
for the panelists to review the summary documents provided and to 
discuss the issues relevant to the taxonomic and systematic issues for 
the subspecies (see workshop agenda in Amec 2015, p. A-1). During the 
contracting process, the Service developed a Statement of Work with 
five suggested questions that the panelists consider during the 
workshop regarding the taxonomy and systematics issues related to the 
coastal California gnatcatcher. These are provided in the Amec Foster 
Wheeler science panel report (Amec 2015, p. A-2). Service personnel did 
not participate in the workshop discussions or interact with the 
panelists, with the exception of a brief question-and-answer session on 
the second day when the panelists requested clarification related to 
previous Federal actions and Service policies (for example, the DPS 
policy).
    In our Statement of Work, we indicated that the panelists (to be 
selected by Amec) would include avian genetic and taxonomic researchers 
as well as experts in avian phylogeographic studies. We also requested 
that the Contractor would have sufficient experience and understanding 
in the field of genetics in order to be able to lead and facilitate the 
discussion of the panelists. The proposal for the facilitated expert 
panel workshop submitted by Amec to the Service on May 5, 2015 (revised 
May 13, 2015), included a summary of the six panelists' experience 
(ranging from 19 to 35 years each) and general areas of expertise in 
the fields of molecular genetics, avian conservation genetics, avian 
systematics, conservation genetics, population genetics, and avian 
molecular genetics. One of the panelists selected by Amec was 
subsequently replaced due to a scheduling conflict. The proposal also 
included the qualifications of the facilitator and Amec's Project 
Manager. We received the panelists' individual curriculum vitae with 
the draft and final workshop reports. After reviewing the panelists' 
individual curriculum vitae, we confirmed the six panelists are 
qualified experts in the fields of molecular genetics, avian 
conservation genetics, avian systematics, conservation genetics, 
population genetics, and avian molecular genetics. The Project Manager 
also noted in Amec's proposal that several panelists had requested that 
their individual memoranda be presented in the final report without 
attribution. Although we did not have knowledge of the attribution of 
the individual memorandums to the six panelists, we determined that all 
panelists are subject matter experts qualified to evaluate the 
scientific information presented in the petition. Additional details 
about the workshop process and the panelist discussions are available 
in the science panel summary report (Amec 2015, pp. 5-7).
    After the workshop, each panelist individually prepared a 
memorandum that addressed topics relevant to the scientific information 
presented in the petition (for example, Zink et al. 2013) and to the 
subspecific taxonomic status of the coastal California gnatcatcher. We 
discuss the key information from those memoranda in the following 
section. In discussing specific supporting information and other 
comments presented in the individual memoranda, we refer to the 
panelists and their memos by the numbers randomly assigned to them by 
Amec Foster Wheeler (Panelist 1, Panelist 2, etc.) or to the Amec 
Workshop Report page number (Amec 2015).

Key Information From the Science Panel Memoranda

    The panelists were not asked to reach a consensus. However, all six 
panelists found that the arguments presented by Zink et al. (2000; 
2013) were not convincing, and that the coastal California gnatcatcher 
is currently a

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valid (distinguishable) subspecies. Panelists made the following 
points:
     The criteria used to distinguish subspecies should include 
multiple lines of evidence, such as morphology, genetics, and ecology. 
As such, the use of phylogenetic criteria alone to distinguish (or fail 
to distinguish) the coastal California gnatcatcher as a subspecies is 
not appropriate.
     Patterns of differentiation should be applied based on 
proposed mechanisms of evolution and the geologic age at which those 
events occurred, and the appropriate tools must be applied to 
adequately test those hypotheses. Based on the biogeographic history of 
the region, the infraspecific divergence in the coastal California 
gnatcatcher is of recent origin (less than 12,000 years before present, 
see Zink et al. 2000, 2013); therefore, the subspecies is likely in the 
earliest stages of adaptive differentiation.
     Relatedly, the amount of divergence in a small number of 
neutral genetic markers (genes that are not subject to selective 
pressures and, therefore, change slowly over time through accumulation 
of random changes) is likely to be small and unlikely to demonstrate 
genetic differences between subspecies.
     The genetic analyses conducted by Zink et al. (2000, 2013) 
contain insufficient information to detect subspecies limits. The 
panelists stated that the methods of Zink et al. (2000; 2013) for 
analyzing the data were not appropriate for detecting recent, 
infraspecific divergence, as likely occurred in the case of the coastal 
California gnatcatcher.
     Panelists generally concurred that genetic studies that 
examine neutral genetic markers should not overturn existing subspecies 
boundaries, especially when divergence is not detected.
    Panelists provided detailed information on the limitations of the 
conclusions that can be made based on the analyses presented in Zink et 
al. (2013) and other currently available information. In addition, the 
panelists concluded that two prior peer reviews had addressed the 
morphological data on the coastal California gnatcatcher, and that 
there was no new information in the materials provided or in the 
petition regarding the morphology of the coastal California 
gnatcatcher. Several panelists also provided recommendations for 
additional analyses and areas of research for future taxonomic studies.
    In late 2015, Zink et al. submitted to the Service what was then an 
in-press manuscript (Zink 2015c, pers. comm.) that was subsequently 
published in The Auk: Ornithological Advances in January 2016 
(available electronically December 2015). The article (Zink et al. 
2016) presented additional interpretation and analysis of the data and 
models from Zink et al. (2013). Zink et al. (2016) responded to the 
criticisms of McCormack and Maley (2015) and argued that: (1) 
Subspecies listed under the Act should have one major character that is 
distinct or diagnostic; (2) the choice of loci and statistical methods 
used by Zink et al. (2013) to analyze nuclear DNA were correct; and (3) 
interpretations of the niche analysis in Zink et al. (2013) are 
correct, and the California gnatcatcher overall has a wide ecological 
tolerance. Zink et al. (2016) concluded that no evidence for genetic 
structure exists among California gnatcatchers, and thus that the 
coastal California gnatcatcher is not a valid subspecies. Because the 
in-press article was received after the science panel met in August 
2015, the information presented in this paper was not available for 
review by panelists. However, the Service reviewed Zink et al. (2016) 
and took into consideration its interpretation of the best available 
data in weighing all the evidence, including the data and analyses 
provided by the panelists, in making a final determination. Additional 
information regarding our analysis of Zink et al. (2016) is provided in 
the Listable Entity Determination section below.

Listable Entity Determination

    The petition asserts that the coastal California gnatcatcher should 
be delisted. Working within the framework of the regulations for making 
delisting determinations, as discussed above, the petition asserts that 
the original data we used in our recognition of the coastal California 
gnatcatcher as a subspecies, and thus a listable entity under the Act, 
were in error. In determining whether to recognize the coastal 
California gnatcatcher as a valid (distinguishable) subspecies, we must 
base our decision on the best available scientific and commercial data. 
Additionally, we must provide transparency in application of the Act's 
definition of species through careful review and analyses of all the 
relevant data. Under section 3 of the Act and our implementing 
regulations at 50 CFR 424.02, a ``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. 
As such, a ``species'' under the Act may include any taxonomically 
defined species of fish, wildlife, or plant; any taxonomically defined 
subspecies of fish, wildlife, or plant; or any distinct population 
segment of any vertebrate species as determined by us per our Policy 
Regarding the Recognition of District Vertebrate Population Segments 
(61 FR 4721; February 7, 1996).
    Our implementing regulations provide further guidance on 
determining whether a particular taxon or population is a species or 
subspecies for the purposes of the Act: ``the Secretary shall rely on 
standard taxonomic distinctions and the biological expertise of the 
Department and the scientific community concerning the relevant 
taxonomic group'' (50 CFR 424.11). For each species, section 4(b)(1)(A) 
of the Act mandates that we use the best scientific and commercial data 
available for each individual species under consideration. Given the 
wide range of taxa and the multitude of situations and types of data 
that apply to species under review, the application of a single set of 
criteria that would be applicable to all taxa is not practical or 
useful. In addition, because of the wide variation in kinds of 
available data for a given circumstance, we do not assign a priority or 
weight to any particular type of data, but must consider it in the 
context of all the available data for a given species.
    For purposes of being able to determine what is a listable entity 
under the Act, we must necessarily follow a more operational approach 
and evaluate and consider all available types of data, which may or may 
not include genetic information, to determine whether a taxon is a 
distinguishable species or subspecies. As a matter of practice, and in 
accordance with our regulations, in deciding which alternative 
taxonomic interpretations to recognize, the Service will rely on the 
professional judgment available within the Service and the scientific 
community to evaluate the most recent taxonomic studies and other 
relevant information available for the subject species. Therefore, we 
continue to make listing decisions based solely on the basis of the 
best scientific and commercial data available for each species under 
consideration on a case-specific basis.
    In making our determination whether we recognize the coastal 
California gnatcatcher as a distinguishable subspecies, and thus, 
whether the petitioned action is warranted, we will consider all 
available data that may inform the taxonomy of the coastal California 
gnatcatcher, such as ecology, morphology, genetics, and behavior. In 
particular, in this review, we focus on evaluating all new submitted 
and available data and analyses, including but not limited to the 2014 
petition, the

[[Page 59958]]

studies by Zink et al. (2000; 2013; 2016), McCormack and Maley (2015), 
and the science panel report (Amec 2015, entire) in the context of all 
the available data.
    We do not address the petition's critiques or its citations to 
analyses and alternative interpretations of Atwood's morphological data 
(Thornton and Schiff 2014, pp. 14-21). In our 2011 90-day finding (76 
FR 66255; October 26, 2011), we noted that on March 27, 1995, the 
Service published in the Federal Register (60 FR 15693) an extensive 
review of the Atwood data (including independent scientific analyses of 
the Atwood data) received during the public comment periods concerning 
the subspecies classification of the coastal California gnatcatcher. In 
that 1995 Federal Register document, we affirmed our earlier 
determination that the coastal California gnatcatcher is a valid 
subspecies (58 FR 16742, March 30, 1993; 58 FR 65088, December 10, 
1993) and affirmed the coastal California gnatcatcher's threatened 
status under the Act. Thus, all of these critiques, analyses, and 
interpretations regarding Atwood's findings were previously considered 
by the Service in the 1995 listing determination and the 2011 petition 
decision. The 2014 petition provided no new information or analysis 
related to the morphological study of the coastal California 
gnatcatcher.
    In our 2011 90-day finding (76 FR 66255; October 26, 2011), we 
provided a summary of our use of Atwood's morphological data as a part 
of a large suite of previous studies. We continue to consider those 
data to be part of the best scientific and commercial data available 
regarding taxonomy of the coastal California gnatcatcher. Furthermore, 
on September 15, 1995, the U.S. District Court for the District of 
Columbia dismissed with prejudice the lawsuit by the Building Industry 
Association of Southern California and other plaintiffs that sought to 
overturn the listing of the coastal California gnatcatcher. As part of 
that lawsuit, the court ordered the Service to release to the public 
the underlying data that formed the basis for Dr. Atwood's taxonomic 
conclusions. Given the court's 1995 ruling upholding the Service's 
recognition of the coastal California gnatcatcher as a valid 
subspecies, and the fact that no new data were presented by petitioners 
regarding morphological characteristics of California gnatcatchers, we 
do not further examine the petition's arguments about morphological 
data in this 12-month finding.
    We also do not discuss the petition's assertions that because the 
Service has relied on mtDNA evidence in evaluating other species or 
subspecies for listing under the Act (Thornton and Schiff 2014, Exhibit 
D), we may not discount such information here. As discussed above, we 
base each listing decision on the best scientific and commercial data 
available for the individual species under consideration. Those data 
may or may not include results of genetic evaluations, including mtDNA 
analyses. Any data from genetic studies must be considered in the 
context of the suite of other relevant data available for a particular 
species. We previously considered the mtDNA data referenced in the 
petition along with other available information in our 2011 petition 
finding and concluded that the best available scientific and commercial 
information supports recognition of the coastal California gnatcatcher 
as a distinguishable subspecies.
    As such, in this determination, we focus on the following topics: 
(1) Defining subspecies criteria for the coastal California 
gnatcatcher; (2) interpretations of the results of analyses from 
genetic studies used in the petition; and (3) interpretations of the 
results of an ecological niche model used in the petition.

Defining Subspecies Criteria for the Coastal California Gnatcatcher

    In determining whether to recognize the coastal California 
gnatcatcher as a distinguishable subspecies, we must first define the 
criteria used to make this decision given the available information. 
The petition notes that subspecies divisions are often arbitrary or 
subjective (Thornton and Schiff 2014, pp. 21-22). Indeed, within the 
ornithological and taxonomic literature, there are no universally 
agreed-upon criteria for delineating, defining, or diagnosing 
subspecies boundaries. Historically, multiple researchers (for example, 
Mayr (1943); Rand (1948); Amadon (1949)) proposed that at least 75 
percent of the individuals of a subspecies should be separable from 
other populations by a particular characteristic. The American 
Ornithologists' Union (AOU) Committee on Classification and 
Nomenclature of North and Middle American Birds (formerly known as the 
Check-list Committee), the widely recognized scientific body 
responsible for standardizing avian taxonomy in North America (Haig et 
al. 2006, p. 1587), gives their standard definition of subspecies with 
guidance on interpreting criteria (AOU 2015, entire):

    Subspecies should represent geographically discrete breeding 
populations that are diagnosable from other populations on the basis 
of plumage and/or measurements, but are not yet reproductively 
isolated. Varying levels of diagnosability have been proposed for 
subspecies, typically ranging from at least 75 to 95 percent. 
Because subspecies represent relatively young points along an 
evolutionary time scale, genetic differentiation between subspecies 
may not necessarily parallel phenotypic divergence. Thus, subspecies 
that are phenotypically but not genetically distinct still warrant 
recognition if individuals can be assigned to a subspecies with a 
high degree of certainty.

    In the scientific literature, multiple authors have provided 
definitions with a wide-ranging variety of criteria for defining or 
refining the taxonomic rank of subspecies for avian taxa (for example, 
McKitrick and Zink (1988); Amadon and Short (1992); Strickberger 
(2000); Helbig et al. (2002); Patten and Unitt (2002); Avise (2004); 
Zink (2004); Futuyma (2005); Cicero and Johnson (2006); Haig et al. 
(2006); Phillimore and Owens (2006); Rising (2007); Skalski et al. 
(2008); Fitzpatrick (2010); Haig and D'Elia (2010); Patten (2010); 
Remsen (2010); and Patten (2015)); however, there is no consensus in 
the literature for defining subspecies criteria for avian taxa 
(Sangster 2014, p. 212).
    The science panelists who were convened to evaluate the taxonomy 
and systematics of the coastal California gnatcatcher provided their 
individual recommendations for criteria used to define subspecies as 
described in the scientific literature. Most of the panelists 
highlighted the AOU subspecies criteria as the standard for avian taxa 
(Amec 2015, Panelist 1, p. 101; Panelist 3, p. 111; Panelist 4, pp. 
116-117; Panelist 5, p. 124; Panelist 6, p. 135). Panelist 2 provided 
the definition of subspecies from Haig et al. (2011), which states 
that, ``subspecies is generally defined as a breeding population that 
has measurably distinguishable genotypes or phenotypes (or both) and 
occupies a distinct geographic area within its species range (Avise 
2004, Patten 2010, Remsen 2010).'' However, all panelists affirmed that 
multi-evidence criteria should be used for distinguishing the coastal 
California gnatcatcher as a subspecies.
    The petition bases its argument for delisting on the genetic 
analyses presented in Zink et al. (2000) and Zink et al. (2013) and the 
results of the ecological niche model discussed in Zink et al. (2013). 
The conclusions drawn from these analyses are based on the authors' 
overall frame of reference that the ``gnatcatcher populations and 
subspecies are not monophyletic'' at either the geographic or taxonomic 
level of organization (Zink et al. 2016, p. 65),

[[Page 59959]]

and that no monophyletic units are found within the gnatcatcher 
consistent with any ``hierarchical Linnaean taxon'' or any other unit 
based on the ``traditional 75 percent rule'' to define subspecies (Zink 
et al. 2016, p. 65). In other words, the petition relies on a cladistic 
classification approach, generally used for describing species rather 
than subspecies, and which is based entirely on monophyletic taxonomic 
groups (Mallet 2007, p. 1). This phylogenetic species concept also 
invokes the concept of reciprocal monophyly (exclusive coalescence), in 
which all individuals in a given group have a common ancestor not 
shared by any other group, and all individuals in that group should be 
genetically distinct and distinguishable from members of other 
populations.
    However, the science panelists explicitly rejected the use of 
reciprocal monophyly for defining subspecies status for the coastal 
California gnatcatcher (Amec 2015, p. 105). Reciprocal monophyly is 
rarely used by avian taxonomists, even in defining taxa at the species 
level, and this approach is not shared by the majority of scientists 
(Amec 2015, pp. 126, 104; Sangster 2014, p. 208). Many scientists 
consider subspecies to be incipient species that are not yet fully 
reproductively isolated (Amec 2015, p. 126), and the subspecies of the 
California gnatcatcher have likely not been separated for sufficient 
time to display characteristics of reciprocal monophyly (Amec 2015, p. 
106). Additionally, because there are a number of gene lineages 
contained within any population, if a population becomes geographically 
(or genetically) divided into two distinguishable entities, a 
significant amount of time is required before each of the branches will 
become ``fixed for different, reciprocally monophyletic gene lineages 
at any single gene'' (Mallet 2007, p. 7).
    In evaluating the best available information regarding the 
taxonomic and systematic status of the coastal California gnatcatcher, 
we disagree with the petition's argument, and conclude that a multi-
evidence criteria approach is most appropriate for distinguishing 
subspecies. In accordance with the science panelists and conclusions in 
the scientific literature (Sangster 2014; McCormack and Maley 2015), we 
do not accept that reciprocal monophyly is an appropriate criterion for 
distinguishing subspecies of avian taxa in the case of the coastal 
California gnatcatcher.
    We next examine the available data regarding factors appropriate 
for evaluating the subspecific status for the coastal California 
gnatcatcher. As described above, we reviewed and summarized the 
available morphological data in detail in previous Federal actions, 
including the 2011 90-day finding (76 FR 66255; October 26, 2011). No 
new information regarding the morphological characteristics of 
California gnatcatchers was submitted in the petition or in response to 
our request for information in our 2014 90-day finding (79 FR 78775; 
December 31, 2014). Because there was no new morphological information 
or analyses to review, the panelists considered the previous peer 
reviews and summaries of morphological data to represent the best 
available information and relied on this information in their 
evaluations (Amec 2015, p. 4). In the following sections, we, 
therefore, focus our discussion on the genetic and ecological 
information presented in the petition to delist the coastal California 
gnatcatcher.
    We note that our evaluation applies specifically to the coastal 
California gnatcatcher and not to avian subspecies in general. Each 
possible subspecies has been subject to unique evolutionary forces, 
different methods of selection will act on each subspecies (genetic 
drift versus allopatric speciation), and the potential divergence time 
(recent versus more distant) will, therefore, lead to different 
signals, particularly genetically; as such, the methods for detecting 
each will be different (Amec 2015, pp. 101-102).

Analyses of Genetic Data Presented in the Petition

    The petition relies on the results of a nuclear DNA analysis 
presented by Zink et al. (2013) as evidence that delisting the coastal 
California gnatcatcher is warranted based on taxonomic error. As 
described above, this analysis examined eight nuclear loci and 
concluded that no genetic structure was apparent within California 
gnatcatchers. In other words, any differences in California 
gnatcatchers represent a geographic cline, and thus all differences 
occur gradually along a north-south gradient and do not represent sharp 
distinctions between unique groups. The petition states that Zink et 
al. (2013) provided the data and analysis requested by the Service in 
our 2011 90-day finding (76 FR 66255; October 26, 2011) (Thornton and 
Schiff 2014, p. 30) and the best available information supporting the 
assertion that the coastal California gnatcatcher is not a valid 
subspecies. It is true that we recognized in the 2011 petition finding 
that results from nuclear DNA analyses are likely to better detect 
genetic evidence of population differentiation than mtDNA data (76 FR 
66258; October 26, 2011). However, we did not suggest that the results 
of nuclear DNA studies would or should be considered determinative of 
the coastal California gnatcatcher's taxonomic status. Rather, we 
stated that future consideration of the status of the taxon ``should 
wait for analyses of a variety of morphological, genetic (including 
nuclear and mtDNA) and behavioral evidence'' (76 FR 66258; October 26, 
2011). Consistent with our 2011 petition finding, we consider multi-
evidence criteria involving multiple lines of genetic, morphological, 
and ecological scientific data to provide the best approach to 
determining the taxonomic status of the coastal California gnatcatcher.
    With regard to the genetic evidence relied on in the current 
petition, multiple commenters from the scientific community and members 
of the science panel expressed concern regarding the nuclear DNA 
analysis and conclusions of Zink et al. (2013). Several panelists 
stated that Zink et al. (2013) chose markers with slow mutation rates 
that are inappropriate to evaluate the status of the coastal California 
gnatcatcher, given that their lineage diverged recently, likely within 
the last 12,000 years (for example, Panelist 6; Amec 2015, p. 147). For 
example, one science panelist stated that the loci chosen by Zink et 
al. (2013) do not in fact meet the standards recommended by the Service 
and the 2004 science panel, as described in the 2011 petition finding 
(76 FR 66255; October 26, 2011), given that loci with high mutation 
rates were requested (Amec 2015, p. 126).
    We received information from the panelists and others from the 
scientific community (in response to our 90-day finding (79 FR 78775; 
December 31, 2014)) regarding the statistical methods presented in Zink 
et al. (2013). For example, Panelist 4 stated that the statistical 
analysis chosen for the nuclear loci genetic analysis (STRUCTURE) might 
be inappropriate because this method is not a statistically powerful 
approach for identifying genetic distinctions when divergence (genetic 
separation between two new groups) is modest, particularly given the 
small sample sizes used by Zink et al. (2013) (Amec 2015, p. 118).
    We also received information regarding the approach and analysis of 
the nuclear markers used by Zink et al. (2013). Several commenters and 
members of the science panel found that McCormack and Maley's (2015) 
reanalysis of the data was more appropriate for considering subspecies 
than the original analysis by Zink et al. (2013). Additionally, several 
panelists found that the McCormack and Maley

[[Page 59960]]

(2015) analysis did support an observed population structure in 
California gnatcatchers (Amec 2015, Panelist 2, p. 108; Panelist 4, p. 
118; Panelist 5, p. 126). However, one panelist (Amec, pp. 145-146) 
criticized both Zink et al. (2013) and McCormack and Maley (2015) for 
having too small of a sample size to reach any conclusions from 
analysis of nuclear data. We acknowledge that the sample sizes for the 
studies are small; however, as previously discussed, we must rely upon 
the best available scientific and commercial data for making our 
conclusions; as such, we take both interpretations of the study into 
consideration in our analysis.
    As previously noted, Zink et al. (2016) presented a rebuttal to 
many of the critiques raised by McCormack and Maley (2015); however, 
this article was not available when the science panel workshop was 
convened. Our review of the information presented indicates that Zink 
et al. (2016) do not provide substantial defense to the claims that the 
markers they selected were inappropriate for analyzing population 
structure of the coastal California gnatcatcher. Zink et al. (2016) 
state that these loci and the mtDNA used in Zink et al. (2000) have 
detected evolutionarily distinct lineages in other species along the 
same distribution of the coastal California gnatcatcher, such as the Le 
Conte's thrasher (Toxostoma lecontei), the curve-billed thrasher (T. 
curvirostre), and the canyon towhee (Melozone fusca). However, their 
comparison is not supported by documentation of any potential genetic, 
morphological, or ecological similarities between the coastal 
California gnatcatcher and these species that would provide a strong 
basis for their conclusion that unrelated species with different life 
histories and evolutionary histories might necessarily experience 
similar rates and patterns of genetic divergence.
    Zink et al. (2016) also contend that the reanalysis of the data 
presented in McCormack and Maley (2015) is invalid because the data do 
not represent the original subspecies boundary as defined by Atwood 
(1988) at 28[deg] N. (Zink et al. (2016, p. 63) also perform a 
statistical analysis finding no structure in the population regardless 
of how it is divided). Still, we note that the range of the coastal 
California gnatcatcher subspecies as defined by the original listing in 
1993 (58 FR 16742; March 30, 1993) is at 30[deg] N., and several 
reanalyses of the morphological data (Atwood 1991, entire; Banks and 
Gardner 1992, entire; Link and Pendleton 1994, entire) have supported 
the southern limit of the range of the subspecies to be at 
approximately 30[deg] N.
    We reaffirm that the best available information indicates that the 
30[deg] N. is still the appropriate line to delineate the approximate 
southern limit of the subspecies' range, and, therefore, the genetic 
analyses based on that boundary are appropriate for considering the 
subspecific status. In support of this assessment, one science panel 
member also questioned the division of subspecies boundaries by Zink et 
al. (2013), stating that the presence of rare alleles north of the 
30[deg] N. boundary provides additional supporting scientific 
information that the coastal California gnatcatcher subspecies is 
valid. This panelist further noted that the choice by Zink et al. 
(2013) to use the 28[deg] N. boundary does not answer the question as 
to whether genetic structure would have been detected if the accepted 
30[deg] N. latitudinal break was chosen (Amec 2015, p. 127). Zink et 
al. (2016, p. 61) dismiss the significant genetic structure observed in 
two loci in the reanalysis of McCormack and Maley (2015), stating that 
their statistical result ``was driven by an excess of rare alleles as a 
result of larger sample sizes in the north . . . as well as by 
population expansion'' (citing Zink et al. 2013). However, this 
assessment does not address the implication of rare alleles in the 
north, which, as noted by the science panelists and McCormack and Maley 
(2015), provides evidence of population structure. In fact, one panel 
member noted that the observation of rare alleles found in McCormack 
and Maley (2015) was especially significant given that the smaller 
population size in the north has been attributed to the presence of 
reported population declines or bottlenecks, which often remove rare 
alleles (Allendorf et al. 2013, p. 109) (Amec 2015, p. 127).
    An additional difference in the views regarding the genetic 
analysis presented in Zink et al. (2013) relates to how scientists 
interpret negative results. The petition argues that a lack of 
structure detected means that such genetic or population structure is 
overall lacking. However, negative results (such as failure to detect 
structure) can be interpreted as either the true absence of genetic 
structure or as simply inconclusive. Several panelists stated that they 
found the results of Zink et al. (2013) to be inconclusive overall. In 
addition, one panel member noted that the methods used in Zink et al. 
(2013) might lack adequate statistical power to detect population 
structure, given that relatively few loci were used (Amec 2015, p. 
125). This highlights the significance of the detection of structure by 
McCormack and Maley (2015, pp. 382-383), despite the small number of 
markers used.
    We also received information from the science community and from 
the panelists regarding the use of only a small number of neutral 
genetic markers by Zink et al. (2013). Two panelists stated that the 
observed morphological difference between the northern and southern 
populations of California gnatcatchers is likely only caused by a very 
small portion of the genome (Santure et al. 2013, p. 3959; Poelstra et 
al. 2014, p. 1414; Amec 2015, pp. 113, 117). Thus, the chance of 
detecting that difference using few neutral genetic markers is very 
small. The apparent absence of species-wide genetic structure at a 
handful of neutral markers unconnected to phenotype does not 
necessarily indicate the absence of important adaptive differences 
among specific groups (Amec 2015, p. 118).
    The petition contends that use of DNA data can result in more clear 
and decisive answers regarding subspecies limits than morphological 
characteristics (Thornton and Schiff 2014, p. 21). We concur with the 
petition's assertions and the panelists' summaries that genetic data 
can in some cases provide clear diagnostic information regarding the 
geographic limits of related populations, which can then be interpreted 
and applied in assessing taxonomic treatments. However, we also concur 
with the panelists that evaluation of genetic data must be thorough, 
analyzed using genetic markers appropriate for the time scale of likely 
divergence, and analyzed using appropriate statistical methods. We 
agree with the panelists that the number and type of genes tested by 
Zink et al. (2013) were insufficient, and that the analysis relied upon 
in the petition was too limited to ``prove the negative''; that is, we 
do not agree with the assertion in the petition that the coastal 
California gnatcatcher subspecies is not valid based on analysis of DNA 
data and the original listing was in error. Rather, we conclude that 
the best available genetic information, including independent 
evaluations from the science panelists and reanalyses of data from 
members of the scientific community (for example, Andersen 2015, pers. 
comm.; McCormack and Maley 2015), indicates that there is some genetic 
evidence for population structure in the California gnatcatcher and 
that this evidence provides some support for the distinguishability of 
the coastal California gnatcatcher as a subspecies. As discussed above, 
we consider multi-evidence criteria involving multiple lines of 
genetic,

[[Page 59961]]

morphological, and ecological scientific data to provide the best 
approach to determining the taxonomic status of the coastal California 
gnatcatcher.
    One recommendation made by five of the six science panelists was 
that existing or any newly collected samples be reanalyzed using large 
numbers of genomic data (AMEC 2015, pp. 102, 109, 121-122, 131, 141), 
particularly, thousands to tens of thousands of single nucleotide 
polymorphisms (SNPs) that represent a large portion of the genome. On 
July 6, 2016, Zink sent to the Service an accepted abstract to be 
presented at the 2016 North American Ornithology Conference in August 
(Zink 2016b, pers. comm.). The abstract references a study in which 
V[aacute]quez-Miranda and Zink examine thousands of SNPs for the 
coastal California gnatcatcher and other Baja California bird species. 
The authors state that the study results show a lack of population 
structure in the coastal California gnatcatcher (Zink 2016b, pers. 
comm.).
    The science panelists who recommended the use of SNPs included 
several provisos. They cautioned that the SNP dataset be analyzed using 
samples from individuals across the range of the California gnatcatcher 
species, appropriate hypothesis testing be used, appropriate 
statistical methods be used (for example, testing for outlier loci 
(Funk et al. 2012, p. 493)), and the data be released publicly to allow 
for transparency of analysis (AMEC 2015, pp. 104, 121, 131, 141, 151). 
If incorrect methodology is used, the SNP analysis will unlikely be 
able to identify adaptive divergent groups, particularly given that the 
vast majority of SNPs in any dataset will be neutral (Amec et al. 2015, 
p. 131; Funk et al. 2012, p. 492-494). As stated previously, given the 
recent genetic separation (divergence) of the coastal California 
gnatcatcher, adaptive divergence of its genomic structure (that is, 
those few key genes responding to local selection pressures) is likely 
represented in only a few SNP loci, which can be difficult to locate 
even within a large set of SNPs (Amec 2015, p. 121).
    The underlying study identified by Zink (2016b, pers. comm.) has 
not been provided to us and has not been peer-reviewed or published. 
The abstract submitted by Zink (2016b, pers. comm.) did not include 
information regarding the sampling methods used in the study or the 
statistical methods used to analyze the samples. The division between 
subspecies of California gnatcatchers used by V[aacute]quez-Miranda and 
Zink appears to be located farther south than the recognized boundary 
for the subspecies at 30[deg] N., which may confound the results (Zink 
2016b, pers. comm.). In sum, the submitted abstract does not provide 
sufficient detail and information to enable us to adequately evaluate 
its conclusions. Therefore, we do not consider the abstract to provide 
the best available information regarding the subspecific status of the 
gnatcatcher. We will consider the underlying study and data, along with 
all new information provided on the coastal California gnatcatcher, as 
we receive it.

Ecological Niche Model

    The petition also relied on the results of an ecological niche 
model constructed by Zink et al. (2013). In general, an ecological 
niche model represents an estimation of the different niches (for 
example, existing, potential, occupied) and uses estimates of suitable 
conditions from observations of species' presence (Peterson et al. 
2011, p. 271). The model is then constructed (usually with a 
specialized computer program) by overlaying that occurrence data with 
environmental data such as temperature, precipitation, elevation, 
vegetation type, or other habitat characteristics. The model then can 
be used for a variety of functions; for example, it can be used to 
predict an entity's occurrence elsewhere on the landscape or compare 
two populations or subspecies to determine similarities of occurrence, 
as was the case for Zink et al. (2013). The model constructed by Zink 
et al. (2013) compared temperature and precipitation data for habitats 
throughout the range of the California gnatcatcher species as a whole. 
The petition asserts, based on the results of the ecological niche 
model that, although California gnatcatchers in the northern portion of 
their range inhabit a distinctive coastal scrub habitat, no background 
environmental differences or climactic differences are present 
(Thornton and Schiff 2014, p. 30). Zink et al. (2013, p. 456) also 
stated that the results of their niche model indicate that California 
gnatcatchers overall exhibit broad ecological tolerance. The petition 
asserted that the lack of differentiation in the modeled niches is 
indicative of no evidence for subspecies divisions based on the 
variables included in the model.
    In response to our request for information in our 90-day finding 
(79 FR 78775; December 31, 2014), we received differing interpretations 
of the ecological niche model from Zink et al. (2013). For example, 
McCormack and Maley (2015, p. 384) disagreed with the interpretation of 
the niche model results stating that the model results provided 
evidence of strong differentiation between the ecological niches of 
different populations of California gnatcatchers and that Zink et al. 
(2013) had improperly failed to reject their null hypothesis that the 
niches and background areas were equally divergent. We also received 
information from one member of the public who indicated that he was 
provided the opportunity to comment on a draft version of the Zink et 
al. (2013) paper and had identified ``fundamental flaws'' with the 
ecological niche model analysis that were not addressed in the final 
publication (Atwood 2015, pers. comm.).
    The science panelists also disagreed with the interpretation of the 
results of the ecological niche model presented in Zink et al. (2013). 
One panelist cited the lack of clarity as to how the model results were 
interpreted, and the panelist concluded that the model results do show 
differences in the environments inhabited by the coastal California 
gnatcatcher and the other subspecies farther south, in support of the 
conclusions of McCormack and Maley (2015) (Amec 2015, p. 113).
    The ecological niche model presented by Zink et al. (2013) was 
constructed using broad-scale bioclimatic variables. Two panelists 
stated that habitat variables such as vegetation type, structure, or 
composition should have been used for constructing the niche model 
since these variables incorporate a better ecological approach for 
distinguishing subspecies (Amec 2015, pp. 119, 148). In addition, our 
assessment of available vegetation maps from Mexico and documentation 
provided in the literature (for example, Rebman and Roberts 2012, p. 
25) indicate that there is a clear distinction between plant 
communities in Baja California at about the 30[deg] N. latitude and, 
therefore, separate ecological niches; two panelists also emphasized 
the distinction between habitat types (Amec 2015, pp. 104, 129).
    Further support for the interpretation of McCormack and Maley 
(2015) is provided in a new paper by Theimer et al. (2016). In that 
study, the researchers examined an ecological niche model performed by 
Zink (2015, pp. 79-82) for the southwestern willow flycatcher 
(Empidonax traillii extimus). From that model, Zink (2015, pp. 83-84) 
concluded that the southwestern willow flycatcher showed no ecological 
distinctiveness from other willow flycatchers. However, Theimer et al. 
(2016, pp. 292-293) reconstructed the Zink (2015) ecological niche 
model comparing the southwestern willow flycatcher and an unrelated 
species, the yellow warbler (Setophaga petechia), and found no 
ecological distinctiveness

[[Page 59962]]

between the two species. In other words, the model was unable to 
predict any difference in niche (specific habitat) use between the two 
unrelated species. Theimer et al. (2016) state that the reason for this 
is the use of overly broad environmental data that may fail to detect 
ecological distinction on a finer scale, such as that which might be 
expected for subspecies or closely related species that would be 
expected to have some ecological characteristics in common. Theimer et 
al. (2016, p. 294) argued that ecological niche models needed to 
include other habitat characteristics beyond broad measures of 
temperature and precipitation that were used for both the southwestern 
willow flycatcher and the coastal California gnatcatcher (Zink et al. 
2013; Zink 2015). The authors further concurred with McCormack and 
Maley (2015) that Zink et al. (2013) had improperly failed to reject 
the null hypothesis for their niche model (Theimer et al. 2016, p. 
294).
    In the Zink et al. (2016) article, published in response to the 
critique of Zink et al. (2013) by McCormack and Maley (2015), Zink et 
al. (2016, p. 63) defended their interpretation of the California 
gnatcatcher ecological niche model, stating that most widespread 
species occupy different climactic niches. They stated that the fact 
that one portion of the California gnatcatcher species population 
occupies mesic versus xeric habitat does not necessarily indicate that 
there are evolved niche differences (Zink et al. 2016, p. 63). 
Following the publication of the article by Theimer et al. (2016), 
which, as discussed above, presented a differing analysis and 
interpretation of the niche modeling results presented in Zink (2015) 
for the southwestern willow flycatcher, Zink submitted a draft copy of 
a scientific article to the Service on July 1, 2016, responding 
specifically to Theimer et al. (2016)'s critique (Zink 2016a, pers. 
comm.). In the draft article, Zink argues that the reanalysis by 
Theimer et al. (2016) only found weak partitioning between niches and 
that the Zink (2015) study used standard methodology for ecological 
niche models. However, the draft article does not address the larger 
concern raised by Theimer et al. (2016) that the environmental data 
used for the analyses presented in Zink (2015) for the southwestern 
willow flycatcher as well as our similar concern for the niche model 
results presented in Zink et al. (2013) for the coastal California 
gnatcatcher were too coarse to reliably detect differences in 
ecological niches. The best available information indicates that there 
is a difference in habitat used by the populations of the California 
gnatcatchers north of 30[deg] N. latitude and the populations farther 
south, and this habitat difference is consistent with both observed 
morphological differences and the slight genetic variation (as 
described in Analyses of Genetic Data Presented in the Petition above) 
that occurs at the 30[deg] N. latitude that has defined the southern 
limit of the range of the coastal California gnatcatcher since the time 
of listing. Therefore, we conclude that ecological differences help 
distinguish the coastal California gnatcatcher as a subspecies.

Summary

    After careful review of the best available information including 
information presented in the petition, information submitted by the 
public, information provided by the science panelists, and all other 
available information, we find that the results of the genetic analyses 
and niche modeling presented in Zink et al. (2000; 2013; 2016) do not 
provide sufficient information to support the petition's assertion that 
the coastal California gnatcatcher is not a valid subspecies and was 
listed in error. While the analyses presented by Zink et al. (2013) 
provide additional information related to the genetic characteristics 
of the California gnatcatcher, there are significant concerns with the 
methods used and the interpretations of the results. We reject the 
petition's argument that subspecies listed under the Act should have 
one major character that is distinct or diagnostic. We concur with the 
input from the assessments provided by the science panelists and the 
information submitted by the scientific community and the public in 
response to our request for information, and our determination is based 
on all available data that may inform the taxonomy of the coastal 
California gnatcatcher. Multi-evidence criteria involving multiple 
lines of genetic, morphological, and ecological scientific data support 
our recognition of the coastal California gnatcatcher as a 
distinguishable subspecies. Therefore, we conclude that the best 
scientific and commercial information available indicate that the 
coastal California gnatcatcher is a distinguishable subspecies, and we 
continue to recognize it as a listable entity under the Act (that it is 
a ``species'' as defined in section 3 of the Act and is thus eligible 
to be listed as a threatened species or endangered species).
    Having reviewed the best available information regarding the 
taxonomy of the coastal California gnatcatcher and determined it is a 
distinguishable subspecies, we next evaluate information regarding its 
appropriate status under the Act.

Summary of Information Pertaining to the Five Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be an endangered species or 
threatened species because of any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this finding, information pertaining to the coastal 
California gnatcatcher in relation to these five factors is discussed 
below. In considering what factors might constitute threats, we must 
look beyond the mere exposure of the species to the factor to determine 
whether the species responds to the factor in a way that causes actual 
impacts to the species. If there is exposure to a factor, but no 
response, or only a positive response, that factor is not a threat. If 
there is exposure and the species responds negatively, the factor may 
be a threat. We then attempt to determine if that factor rises to the 
level of a threat, meaning that it may drive or contribute to the risk 
of extinction of the species such that the species warrants listing as 
an endangered species or threatened species as those terms are defined 
by the Act. This does not necessarily require empirical proof of a 
threat. The combination of exposure and some corroborating evidence of 
how the species is likely impacted could suffice. The mere 
identification of factors that could impact a species negatively is not 
sufficient to compel a finding that listing is appropriate; we require 
evidence that these factors are operative threats that act on the 
species to the point that the species meets the definition of an 
endangered species or threatened species under the Act.
    In 2010, we conducted a threats analysis in our 5-year review for 
the coastal California gnatcatcher (Service 2010, entire). The 
following analysis of

[[Page 59963]]

factors affecting the species is a summary and update of the 
information presented in the 2010 analysis, which is incorporated by 
reference in this section. We updated the summary presented here, where 
appropriate, with new information from the literature or received from 
the public in response to our request for information in the 90-day 
finding (79 FR 78775; December 31, 2014). As described above in 
Background, the petitioners did not provide information on any of the 
factors. However, several respondents to our request did submit 
information regarding factors affecting the species. Our 2010 5-year 
review is available online at https://www.regulations.gov in Docket 
Number FWS-R8-ES-2014-0058 as a Supporting Document (ID: FWS-R8-ES-
2011-0066-0003) and at our Environmental Conservation Online System Web 
page https://ecos.fws.gov/tess_public/profile/speciesProfile?spcode=B08X 
or by request from the Carlsbad Fish and Wildlife Office (see FOR 
FURTHER INFORMATION CONTACT).
    The following sections include summary evaluations of nine 
potential threats to the coastal California gnatcatcher that we 
identified in the 2010 5-year review as having impacts on the 
subspecies or its habitat throughout its range in the United States and 
Mexico. Potential threats that may impact the subspecies are those 
actions that may affect individuals or habitat either currently or in 
the future, including habitat loss from urban and agricultural 
development (Factor A), grazing (Factor A), wildland fire (Factor A and 
Factor E), vegetation type conversion (Factor A), climate change 
(Factor A and Factor E), disease (Factor C), predation (Factor C), 
fragmentation (Factor A and Factor E), and brood parasitism (Factor E). 
We also evaluate the extent to which existing regulatory mechanisms 
(Factor D) may ameliorate threats associated with the other factors. We 
further note that potential impacts associated with overutilization 
(Factor B) were evaluated in the 2010 5-year review, but we concluded 
that this factor had low or no impacts, overall, across the subspecies' 
range (see Service 2010, p. 21). We did not receive any information 
that impacts associated with overutilization have changed since that 
time. Based on the best available scientific and commercial data, we 
have not identified any new threats to the coastal California 
gnatcatcher since the 2010 5-year review.
    To provide a temporal component to our evaluation of threats, we 
first determined whether we had data available that would allow us to 
reasonably predict the likely future impact of each specific threat 
over time. Overall, we found that, for many threats, the likelihood and 
severity of future impacts became too uncertain to address beyond a 50-
year timeframe. For example:
     The Natural Community Conservation Planning (NCCP) Act, in 
conjunction with the Service's Habitat Conservation Planning (HCP) 
process established under section 10(a)(1)(B) of the Act has 
established long-term NCCP/HCPs within the U.S. range of the coastal 
California gnatcatcher. These plans address development impacts on the 
subspecies and its habitat for 50 to 75 years into the future, 
depending on the plan terms and conditions. We, therefore, consider 50 
years a reasonable timeframe for considering future impacts.
     Laws governing urban development under State environmental 
laws, such as the California Environmental Quality Act and the NCCP 
Act, have remained largely unchanged since 1970 and 1991, respectively; 
thus, we consider existing regulatory mechanisms sufficiently stable to 
support a 25- to 50-year timeframe.
     In analyzing potential impacts from disease, predation, 
grazing, and brood parasitism, we considered all available information 
regarding any future changes that could alter the likelihood or extent 
of impacts. We had no such information extending beyond a 50-year 
timeframe.
     Although information exists regarding potential impacts 
from climate change beyond a 50-year timeframe, downscaled climate 
model projections for this region extend only to the 2060s.
    Therefore, a timeframe of 50 years is used to provide the best 
balance of scope of impacts considered versus certainty of those 
impacts.

Urban and Agricultural Development

    The largest impacts to coastal sage scrub in California, including 
within the range of the coastal California gnatcatcher, both past and 
present, have been due to the effects of urbanization and agriculture 
(Cleland et al. 2016, p. 439). Development for urban use involves 
clearing of existing vegetation. Urban development not only results in 
buildings, roads, and other infrastructure, which are permanent, but 
also includes ``temporary'' impacts, such as pipeline installation or 
heavy equipment activity adjacent to permanent urban development 
(Service 2010, p. 12). Without active habitat restoration actions, 
sites formerly supporting coastal sage scrub vegetation that have 
undergone severe disturbance (from heavy equipment and earth-moving 
activities) require decades to recover (Stylinski and Allen 1999, p. 
550). At the time of listing, we reported that 58 to 61 percent of 
coastal sage scrub habitat had been lost in the three counties that 
supported about 99 percent of the coastal gnatcatcher population in the 
United States; we further identified urban and agricultural development 
as the primary cause for this loss of habitat (58 FR 16751; March 30, 
1993).
    Urban development has continued to occur throughout the range of 
the coastal California gnatcatcher, and in our 2010 5-year review we 
concluded that urban development was an ongoing threat to the 
subspecies (Service 2010, pp. 12-15; 21). For the purposes of this 
status review, we evaluated the current protection status of coastal 
sage scrub (the primary habitat type that supports the coastal 
California gnatcatcher) within the U.S. range of the subspecies using 
geospatial data from the U.S. Geological Survey. We note, however, that 
the distribution of the coastal California gnatcatcher within the 
United States is not necessarily the same as the distribution of 
coastal sage scrub vegetation, because not all coastal sage scrub is 
occupied by coastal California gnatcatchers at any given time (Winchell 
and Doherty 2014, entire). Our analysis for the U.S. portion of the 
range found that 16 percent of coastal sage scrub receives permanent 
protection and minimal human use; 35 percent is permanently protected 
from urban development but allows multiple uses including off-highway 
vehicle use or mining; and 49 percent has no assured protections 
preventing urban development (Service 2016a).
    Currently, much of the subspecies' range in the United States, 
which includes coastal sage scrub as well as other habitat types and 
some partly developed areas, is included in completed NCCP/HCP plans 
where the coastal California gnatcatcher is a ``covered species.'' 
Other NCCP/HCPs within the subspecies' range in the United States are 
in various stages of development, such as the North County Multiple 
Species Conservation Plan in north-central San Diego County, the Orange 
County Transportation Authority M2 NCCP/HCP, and the Rancho Palos 
Verdes NCCP/HCP in Los Angeles County. Within the northernmost portion 
of the subspecies' range in Los Angeles and Ventura Counties, the draft 
Rancho Palos Verdes NCCP/HCP is the only plan in development. Though 
the above list represents plans that are not yet

[[Page 59964]]

permitted or fully implemented, specific conservation measures are 
included in these plans that provide protections for the subspecies and 
its habitat. Implementation of existing HCPs and the ongoing 
development of additional NCCP/HCPs have significantly reduced the 
impacts of urban development to coastal California gnatcatcher habitat 
in the United States by directing urban development away from some 
areas of coastal scrub vegetation while establishing habitat reserves 
that provide conservation benefits to the subspecies and other species. 
These plans are making substantial contributions to the conservation of 
the subspecies by creating a network of managed preserves with linked 
core habitat areas.
    As reported in our 2010 5-year review, we estimated that 59 percent 
of suitable (modeled) coastal sage scrub habitat would be conserved 
with full implementation of four currently permitted NCCP/HCPs and one 
HCP (Service 2010, p. 15). For that analysis, modeled habitat consisted 
of coastal scrub vegetation within the U.S. portion of the range of the 
coastal California gnatcatcher as defined by reported observations, 
elevation, and coastal scrub vegetation (using CDF (2002) vegetation 
data). Using updated vegetation data (CDF 2015), we prepared a new 
geospatial analysis of the previously modeled coastal scrub habitat 
within the subspecies' range and within the planning-area boundaries of 
these NCCP/HCPs (as compared to the 2010 analysis that estimated acres 
of habitat expected to be conserved with full implementation). Based on 
our 2016 analysis, our revised estimate found that these plans 
encompass approximately 55 percent of the coastal sage scrub habitat 
within the U.S. range of the coastal California gnatcatcher (Service 
2016a). We also evaluated the amount of land currently within 
conservation reserves established under these plans and estimated that 
approximately 47 percent of the plans' conservation targets have been 
reached (Service 2016a). This means that 28 percent of habitat in the 
U.S. portion of the coastal California gnatcatcher's range is currently 
conserved by NCCP/HCP plans.
    Outside of the United States, urban development continues and is 
expected to continue into the future (Harper et al. 2011, p. 26; Meyer 
et al. 2016, pp. 10 and 13). Conservation of vegetation within the 
California floristic province of Baja California, Mexico, is receiving 
increasing attention (Meyer et al. 2016, p. 14). Two privately managed 
reserves were recently established in Baja California north of 30[deg] 
N. latitude: (1) Punta Mazo in 2012, which consists of a portion of the 
tidal estuary and sand dune plant community at San Quint[iacute]n Bay; 
and (2) La Reserva Natural Valle Tranquilo, purchased in 2006 and 
expanded in 2013, a 20,000-ac (9,094-ha) reserve south of San 
Quint[iacute]n (Riley 2016, pers. comm.), which is at the very southern 
edge of the California floristic province found in Baja California, at 
the transition from coastal sage scrub/chaparral to desert plant 
communities (Meyer et al. 2016, pp. 12-13). Two Federal parks are also 
found in mountainous areas in northwestern Baja California. However, 
collectively, these four conservation areas encompass very little 
suitable California gnatcatcher habitat. No equivalent regulatory 
mechanisms to the NCCP/HCP process exist in Mexico. In that portion of 
the subspecies' range, Federal, State, and local laws provide limited 
protections to coastal California gnatcatcher habitat (see the Existing 
Regulatory Mechanisms section below).
    In order to estimate the distribution of coastal sage scrub in 
northern Baja California, we created a digital map of the coastal sage 
scrub vegetation defined by and illustrated in Rebman and Roberts 
(2012, p. 22). Based on the digitized version of this published map, we 
created a boundary of the area in northern Baja California that 
contains coastal sage scrub vegetation; this acreage totaled 
approximately 1,862,413 ac (753,691 ha). We then prepared a coarse 
estimation of extant coastal sage scrub vegetation from our delineation 
of Rebman and Roberts (2012, p. 22) by removing those areas that have 
been converted to urban and agricultural development, as estimated from 
composite aerial images from ESRI World Imagery (2013). We estimated 
approximately 1,704,406 ac (689,749 ha) of coastal sage scrub habitat 
in northern Baja California, from 30[deg] N. to the United States-
Mexico border (Service 2016a). This represents a difference of 158,007 
ac (63,942 ha), or about 8.5 percent, from the map prepared by Rebman 
and Roberts (2012, p. 22) of their estimate of coastal sage scrub 
vegetation. Though this figure represents a rough estimate of coastal 
sage scrub vegetation in northern Baja California as of 2013, it is the 
only available analysis of change in amount of coastal sage scrub 
habitat available to us at this time.
    In our 2010 5-year review, we indicated that the threats to the 
coastal California gnatcatcher as a result of agricultural development 
have been tempered in recent years by implementation of regulatory 
mechanisms, especially the State of California's NCCP process and the 
Federal HCP process (Service 2010, p. 14). We also indicated that the 
rate of loss of coastal California gnatcatcher habitat due to 
agricultural development has declined in its southern California range. 
More specifically, 1890-1930 was an intensive agricultural period in 
California with the expansion of dry land farming as well as rapid 
growth of intensively irrigated fruit and vegetable crops (Preston et 
al. 2012, p. 282). An unknown amount of coastal sage scrub within the 
U.S. range of the coastal California gnatcatcher was lost or modified 
during this time period.
    The post-World War II population boom resulted in the conversion of 
many large agricultural areas to urban and suburban developments in 
southern California (Preston et al. p. 282). We used data from the 
Farmland Mapping and Monitoring Program (FMMP) of the Division of Land 
Resource Protection in the California Department of Conservation (CDC) 
to evaluate land use changes in California since 1984 (CDC 2016). 
Although not all areas of some counties have been inventoried, a review 
of these data for San Diego, Orange, Los Angeles, and Riverside 
Counties indicate net losses in prime farmland, from 1984 to 2012, of 
8,508 ac (3,443 ha), 16,874 ac (6,829 ha), 12,326 ac (4,988 ha), and 
82,611 ac (33,431 ha) (CDC 2016), respectively, for a total net loss of 
120,319 ac (48,691 ha). Correspondingly, the reported net gains in 
urban and built-up land for the same time period and the same counties 
were 107,988 ac (43,701 ha), 59,264 ac (23,983 ha), 53,113 ac (21,494 
ha), and 161,615 ac (65,403 ha) (CDC 2016), respectively, for a total 
net increase of 381,980 ac (154,582 ha). These numbers indicate that, 
although agricultural activities have declined in southern California, 
these former farmlands have likely transitioned to urbanized areas 
rather than been allowed to revert to or been restored as native 
habitats.
    Because of the limited regulatory mechanisms in Mexico (see 
Existing Regulatory Mechanisms section below), agricultural activity 
continues to be a stressor within the subspecies' range in that country 
as a result of land clearing for both agriculture and grazing 
practices, particularly in northwestern Baja California (for example, 
Harper et al. 2011, pp. 28 and 31; Meyer et al. 2016, p. 10). These 
effects are likely to continue into the future.
    In summary, urban development was identified as a threat at the 
time of listing and as an ongoing threat in our 2010 5-year review. Our 
2016 evaluation of conserved lands established within

[[Page 59965]]

the U.S. range of the subspecies indicates that approximately 55 
percent of suitable coastal California gnatcatcher habitat is targeted 
for conservation by five regional NCCPs/HCPs, and that 47 percent of 
that goal has been achieved. Although the impact of urban development 
has been curtailed in NCCP/HCP planning areas and has decreased since 
the time of listing, conservation of the subspecies and its habitat 
within the plan areas is not expected until current conservation plans 
are more fully implemented and future conservation plans are approved 
and permitted in other portions of the subspecies' range. Suitable 
habitat that is not yet conserved may be subject to urban development 
or other stressors. Furthermore, although lands within conserved areas 
are not at risk of destruction or modification from development, other 
threats, as discussed below, remain. Additionally, some areas of 
suitable habitat would remain outside areas targeted for conservation 
and could be developed or impacted in the future. Therefore, urban 
development continues to result in the destruction, modification, or 
curtailment of the coastal California gnatcatcher's habitat, and 
represents a current, medium-level stressor to the coastal California 
gnatcatcher across its range in the United States and Mexico that has 
the potential to result in the loss of gnatcatchers at the population 
level and the loss of large but isolated patches of habitat. This 
stressor will continue to impact the subspecies and its habitat into 
the future.
    The impacts to the subspecies related to agricultural development 
is low in the United States, but our recent evaluation of remaining 
coastal sage scrub habitat in Baja California indicates that 
agricultural development remains as a medium- to high-level stressor 
for the subspecies' range in Mexico; we anticipate these impacts will 
continue into the future.

Grazing

    Effects of grazing and browsing from cattle, sheep, and goats 
include eating and trampling of coastal scrub plants. In the 2010 5-
year review, we found that the effects of grazing can result in the 
loss and modification of coastal California gnatcatcher habitat and 
promote vegetation type conversion (the modification of one habitat 
type to another through the effects of one or more stressors working 
individually or in combination--ultimately resulting in the destruction 
of the original habitat type) (see the Vegetation Type Conversion 
section below); at that time, we concluded that grazing was a minor 
threat to the subspecies (Service 2010, pp. 18, 21). Data from the FMMP 
indicate that there have been substantial declines in grazing land in 
San Diego and Riverside Counties from 1984 to 2012. These declines 
range from approximately 19,500 to 34,000 acres (7,689 to 13,759 ha). A 
smaller decline was reported for Orange County (3,265 ac (1,321 ha)), 
and a small increase was reported for Los Angeles County (6,066 ac 
(2,455 ha)) (CDC 2016), though not all areas of these counties have 
been inventoried. Overall, grazing is considered a low-level stressor 
within the subspecies' range in the United States that has a temporary 
impact to only small amounts of habitats and individual gnatcatchers, 
due to the decline in grazing activity and increased regulation of 
grazing by local jurisdictions (for instance, city ordinances).
    The effects of grazing practices to coastal California gnatcatcher 
habitat in Mexico are less concentrated as compared to the United 
States because livestock are seasonally moved. However, grazing in 
coastal scrub habitat in Mexico can still result in vegetation type 
conversion, and as noted above, land clearing for grazing purposes has 
been documented within northern Baja California (Meyer et al. 2016, p. 
10). Therefore, grazing continues to pose a medium-level stressor that 
temporarily impacts large patches of habitat and gnatcatchers at the 
population level within the subspecies' range in Mexico.

Wildland Fire

    Wildland fire can result in the direct loss of the coastal scrub 
plants that the coastal California gnatcatcher uses for foraging, 
breeding, and sheltering. In our 2010 5-year review, we found that 
wildland fire poses a threat to coastal California gnatcatcher habitat 
(Service 2010, pp. 15-18, 21). In that review, we noted that, absent 
other disturbances, coastal scrub vegetation can re-grow in some areas 
post-wildland fire in as little as approximately 3 to 5 years (Service 
2010, p. 21). However, new information suggests that the process needed 
for coastal scrub vegetation to recover sufficiently to provide 
suitable habitat for the coastal California gnatcatcher is more 
complex. Winchell and Doherty (2014, p. 543) examined coastal 
California gnatcatcher recolonization rates after the wildland fires of 
2003 in San Diego County; they found that coastal California 
gnatcatchers recolonize burned areas from the outside in, ``[moving] in 
from the fire perimeter, rather than colonizing the center of the 
burned area immediately'' (see also van Mantgem et al. 2015, p. 136). 
Moreover, the quality of the habitat where recolonization occurs is 
also important, with higher-quality unburned habitat supporting source 
populations for recolonization of burned areas and higher-quality 
burned habitat being more likely to be recolonized as the vegetation 
regrows (Winchell and Doherty 2014, p. 543). This study concluded that 
the coastal California gnatcatcher will recolonize burned areas, but 
that it can take more than 5 years post-burn for populations to reach 
pre-burn occupancy levels, even in higher-quality habitat areas 
(Winchell and Doherty 2014, p. 543).
    Similarly, a 2012 study of coastal California gnatcatchers within 
the Central and Coastal Reserves in Orange County found that, following 
two large fires in 2007 (Windy Ridge and Santiago Fires) that burned 
approximately 75 percent of the Central Reserve, occupancy of surveyed 
plots in 2011 (4 years post-fire) was 10.1 percent (7 of 65 plots) in 
burned areas (Leatherman Bioconsulting Inc. 2012, pp. i, 5). The 
severity of these fires within the Central Reserve also affected 
occupancy, with no occupancy of coastal California gnatcatchers 
observed within severely burned plots, as compared to 23 percent 
occupancy for lightly burned plots (Leatherman Bioconsulting Inc. 2012, 
p. 5). The 2007 fires resulted in a large loss of coastal sage scrub 
habitat in the Central Reserve, and the study found that only 12.7 
percent of plots were occupied by the subspecies as compared to 34.3 
percent of occupied plots for the Coastal Reserve (Leatherman 
Bioconsulting Inc. 2012, p. 5). These findings are supported by an 
observation made by one land manager who submitted information to us in 
response to our request for information in our recent 90-day finding 
(79 FR 78775; December 31, 2014). This land manager indicated that it 
took 10 years of restoration activities after the 2003 San Diego 
wildland fires for coastal California gnatcatcher to return to 
previously occupied habitat in certain burned areas within San Diego 
County (Johanson 2015, pers. comm.). The U.S. Geological Survey, in 
partnership with the San Diego Management and Monitoring Program, is 
conducting additional research to better understand the effects of 
wildland fire on coastal California gnatcatcher occupancy within 
coastal scrub vegetation in southern California (Kus and Preston 2015, 
entire).
    As discussed in our 2010 5-year review (Service 2010, pp. 15-18), 
the frequency of wildland fire has risen due to an increase in rates of 
ignition along

[[Page 59966]]

the urban-wildland interface and controlled burning practices in 
Mexico. The greater number of fires, many of which have burned large 
areas of coastal scrub, has resulted in more areas of young growth 
coastal scrub vegetation that do not provide suitable coastal 
California gnatcatcher habitat. The 2010 5-year review noted that 
roughly 235,226 ac (95,193 ha) of modeled coastal California 
gnatcatcher habitat in the United States burned from 2003 to 2007 
(Service 2010, pp. 15-17), which included several very large fires (see 
Service 2010, p. 16, Figure 3). As noted above (see Urban and 
Agricultural Development section), that analysis used modeled habitat 
consisting of coastal scrub vegetation within the U.S. portion of the 
range of the coastal California gnatcatcher. Using updated fire 
perimeter spatial data from the California Department of Fire and 
Forestry Protection (CDF) (CDF 2014) and our previously defined modeled 
coastal California gnatcatcher habitat, we estimated that 54,429 ac 
(22,027 ha) burned from 2008-2014, which also includes areas that may 
have burned during both the 2003-2007 and 2008-2014 time periods 
(Service 2016a). For southern California fires in 2015, we evaluated 
fire perimeter geospatial data and determined that the Calgrove Fire 
(439 ac (177.6 ha) total) in Los Angeles County burned approximately 
167.5 ac (67.8 ha) of coastal California gnatcatcher habitat (Service 
2016a). In total, from 2003 to 2015, approximately 289,822 ac (117,286 
ha) or about 45 percent of modeled coastal California gnatcatcher 
habitat has burned.
    Wildland fire, and how often it reoccurs in an area, is a major 
contributor to vegetation type conversion from coastal sage scrub to 
annual grassland, a vegetation type that does not support the breeding, 
feeding, or sheltering needs of the coastal California gnatcatcher. 
This is particularly problematic when frequency of wildland fires 
increases above the historic fire regime for coastal sage scrub, which 
increases the incidence of vegetation type conversion. In conjunction 
with several other stressors, wildland fires promote the growth of 
nonnative plant species, which can outcompete and displace native plant 
species. This occurrence results in the modification and, ultimately, 
the loss of coastal scrub habitat. Furthermore, the senescence of these 
annual nonnative annual plants creates higher fuel loads than are found 
in native coastal scrub habitat, accelerating the effects of the 
wildland fire-type conversion feedback loop (see Vegetation Type 
Conversion section below). Our spatial data show that a total of about 
53,343 ac (21,587 ha) of modeled coastal California gnatcatcher habitat 
in the United States has burned at least twice since 2003, with some 
areas having burned three to four times (Service 2016a).
    At the time of listing, wildland fire was identified as a 
substantial threat to the coastal California gnatcatcher and its 
habitat; it was further identified as an ongoing threat in the 2010 5-
year review. Although currently established NCCP/HCPs provide for the 
establishment of coastal sage scrub reserves and include fire 
management as one of their primary objectives, there is no mechanism or 
conservation measure currently in place that can fully prevent the 
recurrence of natural or human-caused destructive wildland fires in 
coastal California gnatcatcher habitat. Therefore, wildland fire 
represents a medium-level stressor leading to the destruction, 
modification, or curtailment of habitat or range of the coastal 
California gnatcatcher that causes large-scale, temporary alterations 
to coastal sage scrub habitat and may result in the loss of some 
gnatcatcher pairs throughout the subspecies' range. According to the 
best available data, it will continue to impact the subspecies and its 
habitat into the future.

Vegetation Type Conversion

    The presence of invasive, nonnative plant species, in combination 
with one or more stressors, such as severe physical disturbance (for 
example, clearing by heavy machinery), livestock activity, wildland 
fire, and anthropogenic atmospheric pollutants (particularly nitrogen 
compounds) can cause a shift from native plants towards a nonnative 
plant community and result in vegetation type conversion. In the 2010 
5-year review, we found that vegetation type conversion of coastal sage 
scrub to nonnative grasses was an ongoing threat to the coastal 
California gnatcatcher, given that nonnative grasses do not support 
breeding for the subspecies (Service 2010, pp. 18-21). Depending on the 
influencing factors, this conversion can occur over various temporal 
and spatial scales. In particular, the nonnative annual plant-wildland 
fire feedback loop can result in the type conversion of large areas of 
habitat over a relatively short period of time (Service 2010, pp. 15-
18). Information provided to us by two land managers within reserves in 
San Diego County indicates that active management to control nonnative 
vegetation is needed to maintain habitat quality due to re-occurring 
wildand fires (Center for Natural Lands Management 2015, pers. comm.; 
Johanson 2015, pers. comm.).
    The NCCP/HCP planning process includes measures for managing 
coastal scrub vegetation, and current management is reducing the 
magnitude of the effects of type-conversion within the range of the 
coastal California gnatcatcher in the United States. Habitat is being 
added as managed reserves under the NCCP/HCPs at a pace that is roughly 
in keeping with habitat losses from urban development and other covered 
activities. However, the process is not yet complete for the decades-
long permits issued for the NCCP/HCPs within the subspecies' range. In 
addition, management plans for each preserve area are not yet complete 
for these long-term plans, and ensuring sufficient resources for 
perpetual management of the reserves that addresses existing and future 
stressors, poses a challenge common to all regional NCCP/HCPs. These 
circumstances can lead to uncertainty regarding whether long-term 
management can adequately address vegetation type conversion in the 
future.
    Therefore, vegetation type conversion represents a medium-level 
stressor leading to the destruction, modification, or curtailment of 
habitat or range of the coastal California gnatcatcher and causing 
long-term habitat alterations and impacts to gnatcatchers across the 
range of the subspecies. The best available scientific and commercial 
information indicates that vegetation type conversion will continue to 
have long-term impacts into the future.

Climate Change

Background

    In this section, we consider observed or expected environmental 
changes resulting from ongoing and projected changes in climate. The 
effects of climate change were not addressed in detail in previous 
status reviews.
    As defined by the Intergovernmental Panel on Climate Change (IPCC), 
the term ``climate'' refers to the mean and variability of different 
types of weather conditions over time, with 30 years being a typical 
period for such measurements, although shorter or longer periods also 
may be used (IPCC 2013a, p. 1,450). The term ``climate change'' thus 
refers to a change in the mean or the variability of relevant 
properties, which persists for an extended period, typically decades or 
longer, due to natural conditions (for example, solar cycles) or human-
caused changes in the composition of

[[Page 59967]]

atmosphere or in land use (IPCC 2013a, p. 1,450).
    Scientific measurements spanning several decades demonstrate that 
changes in climate are occurring. In particular, warming of the climate 
system is unequivocal and many of the observed changes in the last 60 
years are unprecedented over decades to millennia (IPCC 2013b, p. 4). 
The current rate of climate change may be as fast as any extended 
warming period over the past 65 million years and is projected to 
accelerate in the next 30 to 80 years (National Research Council 2013, 
p. 5). Thus, rapid climate change is adding to other sources of 
extinction pressures, such as land use and invasive species, which will 
likely place extinction rates in this era among just a handful of the 
severe biodiversity crises observed in Earth's geological record 
(American Association for the Advancement of Sciences (AAAS) 2014, p. 
17).
    Examples of various other observed and projected changes in climate 
and associated effects and risks, and the bases for them, are provided 
for global and regional scales in recent reports issued by the IPCC 
(2013c, entire; 2014, entire), and similar types of information for the 
United States and regions within it can be found in the National 
Climate Assessment (Melillo et al. 2014, entire).
    Results of scientific analyses presented by the IPCC show that most 
of the observed increase in global average temperature since the mid-
20th century cannot be explained by natural variability in climate and 
is ``extremely likely'' (defined by the IPCC as 95 to 100 percent 
likelihood) due to the observed increase in greenhouse gas (GHG) 
concentrations in the atmosphere as a result of human activities, 
particularly carbon dioxide emissions from fossil fuel use (IPCC 2013b, 
p. 17 and related citations).
    Scientists use a variety of climate models, which include 
consideration of natural processes and variability as well as various 
scenarios of potential levels and timing of GHG emissions, to evaluate 
the causes of changes already observed and to project future changes in 
temperature and other climate conditions. Model results yield very 
similar projections of average global warming until about 2030; 
thereafter, the magnitude and rate of warming vary through the end of 
the century depending on the assumptions about population levels, 
emissions of GHGs, and other factors that influence climate change. 
Thus, absent extremely rapid stabilization of GHGs at a global level, 
there is strong scientific support for projections that warming will 
continue through the 21st century, and that the magnitude and rate of 
change will be influenced substantially by human actions regarding GHG 
emissions (IPCC 2013b, 2014; entire).
    Global climate projections are informative, and in some cases, the 
only scientific information available for us to use. However, projected 
changes in climate and related impacts can vary substantially across 
and within different regions of the world (for example, IPCC 2013c, 
entire; IPCC 2014, entire) and within the United States (Melillo et al. 
2014, entire). Therefore, we use ``downscaled'' projections when they 
are available and have been developed through appropriate scientific 
procedures, because such projections provide higher resolution 
information that is more relevant to spatial scales used for analyses 
of a given species (see Glick et al. 2011, pp. 58-61, for a discussion 
of downscaling).
    Various changes in climate may have direct or indirect effects on a 
species. These may be positive, neutral, or negative, and they may 
change over time, depending on the species and other relevant 
considerations, such as interactions of climate with other variables 
such as habitat fragmentation (for examples, see Franco et al. 2006; 
Forister et al. 2010; Galbraith et al. 2010; Chen et al. 2011; 
Bertelsmeier et al. 2013, entire). In addition to considering 
individual species, scientists are evaluating potential climate change-
related impacts to, and responses of, ecological systems, habitat 
conditions, and groups of species (see, for example, Deutsch et al. 
2008; Berg et al. 2010; Euskirchen et al. 2009; McKechnie and Wolf 
2010; Sinervo et al. 2010; Beaumont et al. 2011; McKelvey et al. 2011; 
Rogers and Schindler 2011; Bellard et al. 2012).

Temperature

    Regional temperature observations for assessing climate change are 
often used as an indicator of how climate is changing. The Western 
Regional Climate Center (WRCC) has defined 11 climate regions for 
evaluating various climate trends in California (Abatzoglou et al. 
2009, p. 1,535). The relevant WRCC climate region for the distribution 
of the coastal California gnatcatcher in southern California is 
primarily the South Coast Region.
    Three indicators of temperature, the increase in mean temperature, 
the increase in maximum temperature, and the increase in minimum 
temperature illustrate trends in climate change in California. For the 
South Coast Region, linear trends (evaluated over a 100-year time 
period) indicate an increase in mean temperatures (Jan-Dec) of 
approximately 2.65 [deg]F (0.49 [deg]F) (1.47  
0.27 [deg]C) since 1895 and 4.17 [deg]F (1.21 [deg]F) (2.32 
 0.67 [deg]C) since 1949 (WRCC 2016, p. 6). Similarly, the 
maximum temperature 100-year trend for the South Coast Region shows an 
increase of about 1.94 [deg]F (0.52 [deg]F) (1.08  0.29 [deg]C) since 1895 and 3.16 [deg]F (1.32 
[deg]F) (1.75  0.73 [deg]C) since 1949 (WRCC 2016, p. 9). 
Likewise, the minimum temperature 100-year trend for the South Coast 
Region shows an increase of about 3.37 [deg]F (0.52 [deg]F) 
(1.87  0.29 [deg]C) since 1895 and 5.19 [deg]F (1.22 [deg]F) (2.88  0.68 [deg]C) since 1949 (WRCC 
2016, p. 12). It is reasonable to assume the rate of temperature 
increase for this region is higher for the second time period (since 
1949) than for the first time period (since 1895) due to the increased 
use of fossil fuels in the 20th century. Even if that is not the 
mechanism, it is clear temperatures have increased in the South Coast 
Region since the start of data collection.
    These observed trends provide information as to how climate has 
changed in the past. However, we must also consider whether and how 
climate may change in the future. Climate models can be used to 
simulate and develop future climate projections. Pierce et al. (2013, 
entire) presented both statewide and regional probabilistic estimates 
of temperature and precipitation changes for California (by the 2060s) 
using downscaled data from 16 global circulation models and 3 nested 
regional climate models. The study looked at a historical (1985-1994) 
and a future (2060-2069) time period using the IPCC Special Report on 
Emission Scenarios A2 (Pierce et al. 2013, p. 841). This IPCC-defined 
scenario was used for the IPCC's Third and Fourth Assessment reports, 
and it is based on a global population growth scenario and economic 
conditions that result in a relatively high level of atmospheric GHGs 
by 2100 (IPCC 2000, pp. 4-5; see also Stocker et al. 2013, pp. 60-68, 
and Walsh et al. 2014, pp. 25-28 for discussions and comparisons of the 
prior and current IPCC approaches and outcomes). Importantly, the 
projections by Pierce et al. (2013, pp. 852-853) include daily 
distributions and natural internal climate variability. Simulations 
using these downscaling methods project an increase in yearly 
temperature for the southern California coastal region ranging from 1.6 
[deg]C to 2.5 [deg]C (2.9 [deg]F to 4.5 [deg]F) by the 2060s time 
period, compared to 1985-1994 (Pierce et al. 2013, p. 844). Averaging 
across all models and downscaling techniques, the simulations project a 
yearly-

[[Page 59968]]

averaged warming of 2.1 [deg]C (3.78[emsp14][deg]F) by the 2060s 
(Pierce et al. 2013, p. 842).

Precipitation

    Precipitation patterns can also be used as an indicator of how 
climate is changing. Killam et al. (2014, entire) evaluated trends in 
precipitation for 14 meteorological stations within all of California 
using annual precipitation data from the National Climatic Data Center. 
This study found an increasing trend in annual precipitation since 1925 
for the northern and central regions of California and decreasing or 
minimal changes in southern California; however, none of the trends for 
these stations were significant (Killam et al. 2014, p. 171). The 
authors concluded that it is unclear as to whether there is a 
recognizable climate change signal in these precipitation records since 
annual variability in precipitation overwhelmed their observed trends, 
particularly precipitation patterns attributed to both the El 
Ni[ntilde]o-Southern Oscillation and the Pacific decadal oscillation 
(multidecadal shifts in warm and cool phases in North Pacific sea 
surface temperatures) (Killam et al. 2014, p. 168).
    Statewide and regional probabilistic estimates of precipitation 
changes for California were evaluated by Pierce et al. (2013, entire). 
Averaging across all models and downscaling methods, the simulations 
projected an annual mean decrease in precipitation for southern 
California (approximately 9 percent for the southern California coastal 
region) over the 2060-2069 time period compared to the mean over the 
1985-1994 time period, but there was significant disagreement across 
the models (Pierce et al. 2013, pp. 849, 854).
    Dynamic downscaled simulations indicate larger increases in summer 
(June-August) precipitation by the 2060s (as compared to statistical 
downscaling methods) within the region of California affected by the 
North America monsoonal flow (Pierce et al. 2013, pp. 851, 855). The 
North American monsoon is a regional-scale circulation that develops 
over the American Southwest during the months of July through 
September, affecting southern California and other locations in this 
region (Douglas et al. 2004, entire). Occasionally, hurricanes and 
tropical storms are captured in the monsoon circulation, which can 
result in heavy summer rains in the normally dry areas of the Southwest 
(Douglas et al. 2004, p. 11). As an example, from July 18-20, 2015, 
remnants of tropical storm Dolores, which had developed into a Category 
4 hurricane off the coast of Baja California, generated record July 
rainfall amounts for several locations in southern California (Fritz 
2015, entire). This storm and additional monsoonal-related rain events 
during the summer of 2015 in southern California were enhanced by 
higher than normal sea surface temperatures and the developing El 
Ni[ntilde]o pattern in the Pacific Ocean (Serna and Lin 2015, p. B5).

Climate Change and Coastal California Gnatcatchers

    The potential changes in climate described above are expected to 
have some effect on the coastal California gnatcatcher and its habitat. 
While the physical and biological mechanisms that result in the 
establishment of coastal scrub or chaparral vegetation are unclear, 
minimum temperatures, maximum temperatures, and precipitation (both 
amount and seasonality) within the southern California coastal region 
represent important influences on the subspecies and its habitat 
(Franklin 1998, p. 745). As noted above, there is little consensus on 
future trends in precipitation in southern California; however, it is 
highly likely that minimum and maximum temperatures will continue to 
rise. Malanson and O'Leary (1995, p. 219) suggested that higher average 
temperatures in the future may create an upslope shift in coastal scrub 
vegetation into areas that are currently occupied by chaparral. This 
may expand or shift areas that currently provide suitable habitat for 
coastal California gnatcatchers. Similarly, because the subspecies' 
distribution is thought to be limited by low temperatures (Mock 1998, 
p. 415), warmer minimum temperatures may also allow for coastal 
California gnatcatchers to survive at higher elevations, thereby 
allowing the subspecies to extend its range into areas previously not 
occupied (Preston et al. 2008, p. 2,512). In contrast, climate change 
may affect nutrient cycling (Allen et al. 1995, entire) or may promote 
a wildland fire regime with increased fire frequency (Batllori et al. 
2013, entire); both of these effects would create conditions more 
favorable for vegetation type conversion to nonnative annual grassland, 
which would be unsuitable habitat for coastal California gnatcatchers.

Climate Change Summary

    Climate change due to global warming is influencing regional 
climate patterns that may result in changes to the habitat for the 
coastal California gnatcatcher into the mid-21st century (approximately 
2060s). While climate change may expand or shift the coastal California 
gnatcatcher's preferred habitat of coastal scrub vegetation in some 
areas, it may also create conditions more favorable for vegetation type 
conversion to unsuitable habitat such as nonnative annual grasslands. 
The best available regional data on current and potential future trends 
related to climate change, within the range of the coastal California 
gnatcatcher, indicate that the effects of climate change is a low- to 
medium-level stressor at the present time that is anticipated to result 
in shifts to the distribution of the subspecies' habitat and that may 
potentially affect gnatcatchers at the individual or population level. 
Based on model projections, we can reliably predict these changes will 
continue into the mid-21st century (2060s).

Disease

    Two diseases have been identified as potential threats to the 
coastal California gnatcatcher, West Nile virus and Newcastle disease. 
These are discussed in greater detail in our 2010 5-year review where 
we concluded that disease was not a significant threat to the 
subspecies (Service 2010, pp. 21-22). Because known West Nile virus 
cases and the range of the coastal California gnatcatcher overlap 
geographically, the subspecies has likely been exposed to West Nile 
virus. While new information suggests that the impact to birds in North 
America has been widespread (George et al. 2015, entire), we have no 
evidence of detection of West Nile virus in the coastal California 
gnatcatcher and no information indicating that this disease has caused 
any decline in coastal California gnatcatcher populations. Furthermore, 
Newcastle disease does not appear to have affected gnatcatchers 
(Service 2010, p. 22). In summary, there is no evidence that disease is 
a stressor at the present time to the coastal California gnatcatcher, 
nor do we expect it to be into the future.

Predation

    The effects of predation on the coastal California gnatcatcher are 
discussed in greater detail in our 2010 5-year review, where we 
concluded that predation is not a significant threat to the subspecies 
(Service 2010, pp. 22-24). Predation undoubtedly occurs among all life 
stages of the coastal California gnatcatcher, but only nest predation 
has been previously identified as affecting recruitment and survival at 
levels that could have potential effects on the population (such as 
reduction in fledging success). Nest predation rates for the coastal 
California gnatcatcher are higher than most open-nesting passerines 
because they occupy a

[[Page 59969]]

naturally predator-rich environment (Service 2010, p. 23). However, the 
life-history strategy of the coastal California gnatcatcher allows 
pairs to re-nest repeatedly, compensating for this potential stressor. 
Therefore, we conclude that predation continues to represent a low-
level impact to the subspecies that affects individual pairs of 
gnatcatchers, but it is not having a population-level impact at the 
present time, and this situation is not expected to change into the 
future.

Fragmentation

    Fragmentation represents a suite of stressors that affect a species 
at various levels and scales. At its simplest, it involves a large, 
continuous block of habitat being broken up into smaller pieces, which 
become isolated from each other within a mosaic of other habitats. It 
is, therefore, not unrelated to habitat destruction and type conversion 
(see the Urban and Agricultural Development section and Vegetation Type 
Conversion sections above). However, changes in proximity to unsuitable 
habitat, distance to other areas of suitable habitat, size of habitat, 
and the length of time a fragment has been isolated may all have 
negative impacts on individuals of the species, such as increased 
predation rates, genetic isolation, or increased risk of local 
extirpation.
    As discussed in our 2010 5-year review, the coastal California 
gnatcatcher is not particularly sensitive to edge or distance effects 
(Service 2010, p. 32). This characteristic is further supported by new 
information indicating that populations of coastal California 
gnatcatchers within the United States are fairly well connected over 
large areas. However, some populations (for example, the Palos Verdes 
Peninsula, greater Ventura County, and Coyote Hills populations) are 
currently separated by large distances by areas of non-habitat and, 
therefore, are not as well connected with the populations in the rest 
of southern California (Vandergast et al. 2014, pp. 8-9). We also noted 
in the 2010 5-year review (Service 2010, p. 32) that the coastal 
California gnatcatcher appeared to be somewhat susceptible to the 
effects associated with small fragment size (area), but new information 
suggests otherwise (Winchell and Doherty 2014, p. 543). Our concern at 
that time was that small areas of habitat would not support coastal 
California gnatcatchers over time and that the loss of the gnatcatcher 
population in a given (small) patch would be permanent. While a given 
patch of suitable coastal California gnatcatcher habitat may not always 
be occupied by the subspecies, these patches of habitat can be 
recolonized over time (Winchell and Doherty 2014, p. 543). Winchell and 
Doherty (2014, p. 543) also found that coastal California gnatcatchers 
gradually recolonize a regrowing burned area from the perimeter inwards 
(see Wildland Fire section above), which indicates that coastal 
California gnatcatchers have some level of sensitivity to spatial and 
temporal elements in habitat fragments.
    Ongoing and anticipated implementation of regional NCCP/HCPs is 
expected to create a network of core-and-linkage habitat areas, thereby 
preventing or reducing the effects of future habitat fragmentation for 
much of the U.S. range of the coastal California gnatcatcher. The core 
areas are large, mostly unfragmented areas, while linkage areas are 
intended to provide continuous or ``stepping stone'' corridors for 
coastal California gnatcatcher movement and dispersal. Thus, as 
indicated by new information from Vandergast et al. (2014, entire) and 
Winchell and Doherty (2014, entire), the ability of the coastal 
California gnatcatcher to move between and recolonize habitat areas 
within the U.S. range, including the existing preserve-and-linkage 
areas, helps to reduce some of the effects associated with habitat 
fragmentation, although connectivity remains somewhat limited at the 
larger scales.
    The new information we have received since the 2010 5-year review 
suggests that fragmentation is a threat of lower magnitude than was 
described at the time of listing. However, the effects of fragmentation 
are more significant than previously recognized for those coastal 
California gnatcatcher populations that have become widely separated 
due to urban development and other habitat losses or modifications (for 
example, wildland fire), particularly the geographically isolated 
populations in Ventura County, Palos Verdes (western Los Angeles 
County), and Coyote Hills (northern Orange County) (Vandergast et al. 
2014, pp. 8, 12). Therefore, we consider the effects of fragmentation 
to represent a low- to medium-level stressor to the subspecies within 
portions of its range, and we can reliably predict that this level of 
stressor will continue into the future.

Brood Parasitism

    Rates of brood parasitism by invasive, nonnative brown-headed 
cowbirds (Molothrus ater) appear to vary throughout the range of the 
coastal California gnatcatcher, depending upon nearby land uses (for 
example, higher rates of brood parasitism near livestock and 
agriculture). Because brown-headed cowbirds are thought to have invaded 
coastal southern California during the 20th century, any rate of brood 
parasitism exceeds the historical rate of parasitism. However, the re-
nesting behavior of the coastal California gnatcatcher following a 
failed nesting attempt enables individual birds to reduce the magnitude 
of this threat, as opposed to some migratory songbirds that do not re-
nest as readily. Additionally, cowbird trapping has been found to be an 
effective tool and has helped to reduce impacts to the coastal 
California gnatcatcher (as informed by monitoring) within many of the 
reserves established under regional NCCP/HCPs (Service 2010, p. 33). 
Additionally, certain ESA section 10(a)(1)(A) permit holders may be 
authorized to conduct coastal California gnatcatcher nest monitoring 
activities that may include the removal of brown-headed cowbird chicks 
and eggs (with minimal disturbance to nesting gnatcatchers). At the 
discretion of the permittee, these activities may further include 
replacement of cowbird eggs with dummy eggs to preclude the abandonment 
of small clutches. These activities help to decrease the impact of 
cowbird parasitism on individual coastal California gnatcatchers. Given 
the subspecies' ability to re-nest following nest failure along with 
ongoing management, we conclude brood parasitism is a low- to medium-
level stressor affecting some populations of coastal California 
gnatcatchers throughout the subspecies' range in the United States, and 
we expect this level of stressor will continue into the future. We have 
no specific information on the impact of brown-headed cowbirds on 
coastal California gnatcatcher populations in Mexico, but brown-headed 
cowbirds occur as a breeding species along the length of the Baja 
California peninsula (see Erickson et al. 2007, p. 583), including 
throughout the range of the coastal California gnatcatcher. We expect 
that the level of impact of this stressor in Mexico is similar to that 
in unmanaged areas of the United States.

Existing Regulatory Mechanisms

    Existing regulatory mechanisms that affect the coastal California 
gnatcatcher include laws and regulations promulgated by Federal and 
State governments in the United States and in Mexico. In relation to 
Factor D under the Act, we consider relevant Federal, State, and Tribal 
laws, regulations, and other such mechanisms that may minimize any of 
the threats we describe

[[Page 59970]]

under the other four factors, or otherwise enhance conservation of the 
species. We give strongest weight to statutes and their implementing 
regulations and to management direction that stems from those laws and 
regulations; an example would be State governmental actions enforced 
under a State statute or constitution, or Federal action under statute. 
For currently listed species, we consider the adequacy of existing 
regulatory mechanisms to address threats to the species absent the 
protections of the Act. Potential threats acting on the coastal 
California gnatcatcher for which governments may have regulatory 
control include impacts associated with urban and agricultural 
development, vegetation type conversion, wildland fire, climate change, 
and brood parasitism.

Federal Mechanisms

National Environmental Policy Act (NEPA)

    All Federal agencies are required to adhere to the NEPA of 1970 (42 
U.S.C. 4321 et seq.) for projects they fund, authorize, or carry out. 
Prior to implementation of such projects with a Federal nexus, NEPA 
requires the agency to analyze the project for potential impacts to the 
human environment, including natural resources. However, NEPA does not 
impose substantive environmental obligations on Federal agencies--it 
merely prohibits an uninformed agency action. Although NEPA requires 
full evaluation and disclosure of information regarding the effects of 
contemplated Federal actions on sensitive species and their habitats, 
it does not by itself regulate activities that might affect the coastal 
California gnatcatcher; that is, effects to the subspecies and its 
habitat would receive the same scrutiny as other plant and wildlife 
resources during the NEPA process and associated analyses of a 
project's potential impacts to the human environment.

Endangered Species Act of 1973, as Amended (Act)

    Upon its listing as threatened, the coastal California gnatcatcher 
benefited from the protections of the Act, which include the 
prohibition against take and the requirement for interagency 
consultation for Federal actions that may affect the species. Section 9 
of the Act and Federal regulations prohibit the take of endangered and 
threatened species without special exemption. The Act defines ``take'' 
as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or 
collect, or to attempt to engage in any such conduct (16 U.S.C. 
1532(19)). Our regulations define ``harm'' to include significant 
habitat modification or degradation that results in death or injury to 
listed species by significantly impairing essential behavioral 
patterns, including breeding, feeding, or sheltering (50 CFR 17.3). Our 
regulations also define ``harass'' as intentional or negligent actions 
that create the likelihood of injury to a listed species by annoying it 
to such an extent as to significantly disrupt normal behavior patterns, 
which include, but are not limited to, breeding, feeding, or sheltering 
(50 CFR 17.3).
    Section 7(a)(1) of the Act requires all Federal agencies to utilize 
their authorities in furtherance of the purposes of the Act by carrying 
out programs for the conservation of endangered species and threatened 
species. Section 7(a)(2) of the Act requires Federal agencies to ensure 
that any action they authorize, fund, or carry out is not likely to 
jeopardize the continued existence of listed species or destroy or 
adversely modify their critical habitat. Because the Service has 
regulations that prohibit take of all threatened wildlife species (50 
CFR 17.31(a)), unless modified by a rule issued under section 4(d) of 
the Act (50 CFR 17.31(c)), the regulatory protections of the Act are 
largely the same for wildlife species listed as endangered and as 
threatened.
    A section 4(d) rule for the coastal California gnatcatcher was 
published on December 10, 1993 (58 FR 65088). Under that rule, 
incidental take of the coastal California gnatcatcher is not considered 
to be a violation of section 9 of the Act if the take results from 
activities conducted pursuant to the NCCP Act of 1991 and in accordance 
with an approved NCCP plan, provided that the Service determines that 
such a plan meets the issuance criteria of an ``incidental take'' 
permit pursuant to section 10(a)(2)(B) of the Act and 50 CFR 
17.32(b)(2). Under the section 4(d) rule, a limited amount of 
incidental take of the coastal California gnatcatcher within subregions 
actively engaged in preparing a NCCP plan will also not be considered a 
violation of section 9 of the Act, provided the activities resulting in 
such take are conducted in accordance with the NCCP Conservation 
Guidelines and Process Guidelines. Under section 10(a)(1)(B) of the 
Act, the Service may issue permits authorizing the incidental take of 
federally listed animal species. Incidental take permittees must 
develop and implement a habitat conservation plan (HCP) that minimizes 
and mitigates the impacts of take to the maximum extent practicable and 
that avoid jeopardy to listed species. Incidental take permits are 
available to private landowners, corporations, Tribal governments, 
State and local governments, and other non-Federal entities. These 
permits can reduce conflicts between endangered species and economic 
activities and develop important partnerships between the public and 
private sectors. As discussed in the Urban and Agricultural Development 
section above, we have issued incidental take permits for regional HCP 
and HCP/NCCPs covering approximately 59 percent of modeled gnatcatcher 
habitat, and two additional HCP/NCCPs are nearing completion.
    Since 1993, the Service has addressed impacts to the coastal 
California gnatcatcher from urban development and other projects 
outside of the NCCP/HCP regional planning effort through the section 7 
process. The projects have included residential and commercial 
developments, highway-widening projects, and pipeline projects, among 
others. Section 7 consultations have also been conducted with the U.S. 
Army Corps of Engineers for Clean Water Act permit applications, and 
other Federal agencies on specific actions. In addition to 
``projects,'' we have consulted with the U.S. Marine Corps to address 
potential impacts to the gnatcatcher and its habitat from military 
training activities on Marine Corps Base Camp Pendleton (Camp 
Pendleton) and Miramar Corps Air Station (Miramar), and we have 
consulted with the U.S. Navy on actions related to the management of 
Naval Weapons Station Seal Beach Detachment Fallbrook (Detachment 
Fallbrook).
    We reviewed the number of formal section 7 consultations for the 
coastal California gnatcatcher in our Tracking and Integrated Logging 
System (TAILS) database (initiated in 2007) that were completed from 
1996 through March 2016. In total, the Carlsbad and Ventura Fish and 
Wildlife Offices completed 320 formal consultations during that time 
period (Service 2016b). In all of these consultations, we concluded 
that, due to the implementation of conservation measures to avoid, 
minimize, and offset impacts to the subspecies and its habitat, effects 
of the proposed actions were not likely to jeopardize the continued 
existence of the coastal California gnatcatcher and were not likely to 
result in the destruction or adverse modification of designated 
critical habitat for the subspecies. We will continue to evaluate 
impacts of proposed projects to the subspecies and its habitat for 
those areas outside of the NCCP/HCPs through other provisions of the 
Act, such as section 7 consultation,

[[Page 59971]]

recovery implementation, and periodic status reviews.
    Our evaluation confirms that urban development and associated 
threats continue for the coastal California gnatcatcher, but listing of 
the coastal California gnatcatcher under the Act as threatened has 
provided protection to the subspecies and its habitat, including the 
prohibition against take and the conservation mandates of section 7 for 
all Federal agencies.

Sikes Act

    The Sikes Act (16 U.S.C. 670a-670f, as amended) directs the 
Secretary of Defense, in cooperation with the Service and State fish 
and wildlife agencies, to carry out a program for the conservation and 
rehabilitation of natural resources on military installations. The 
Sikes Act Improvement Act of 1997 (Pub. L. 105-85) broadened the scope 
of military natural resources programs, integrated natural resources 
programs with operations and training, embraced the tenets of 
conservation biology, invited public review, strengthened funding for 
conservation activities on military lands, and required the development 
and implementation of an Integrated Natural Resources Management Plan 
(INRMP) for relevant installations, which are reviewed every 5 years.
    INRMPs incorporate, to the maximum extent practicable, ecosystem 
management principles, provide for the management of natural resources 
(including fish, wildlife, and plants), allow multipurpose uses of 
resources, and provide public access necessary and appropriate for 
those uses without a net loss in the capability of an installation to 
support its military mission. An INRMP is an important guidance 
document that helps to integrate natural resource protection with 
military readiness and training. In addition to technical assistance 
that the Service provides to the military, the Service can enter into 
interagency agreements with installations to help implement an INRMP. 
The INRMP implementation projects can include wildlife and habitat 
assessments and surveys, fish stocking, exotic species control, and 
hunting and fishing program management.
    On Department of Defense lands, including Camp Pendleton, 
Detachment Fallbrook, and Miramar, coastal California gnatcatcher 
habitat is generally not subjected to threats associated with large-
scale development. However, the primary purpose for military lands, 
including most gnatcatcher habitat areas, is to provide for military 
support and training. At these installations, INRMPs provide direction 
for project development and for the management, conservation, and 
rehabilitation of natural resources, including for the subspecies and 
its habitat. For example, on Camp Pendleton and MCAS Miramar, 
management measures that benefit the coastal California gnatcatcher and 
its habitat include nonnative vegetation control, nonnative animal 
control, and habitat enhancement and restoration (MCB Camp Pendleton 
2007, p. F-25; MCAS Miramar INRMP 2010, pp. 7-18-7-19). Some 
restrictions on training and construction activities also apply during 
gnatcatcher breeding season to reduce impacts on nesting gnatcatchers 
(MCB Camp Pendleton 2007, p. F-25; MCAS Miramar INRMP 2010, pp. 7-18-7-
19).
    Without the protections provided to the subspecies and its habitat 
under the Act (that is, if the coastal California gnatcatcher was 
delisted), there would be less incentive for the Marine Corps or Navy 
to continue to include specific provisions (for example, monitoring) in 
their INRMPs to provide conservation benefits to the subspecies, beyond 
that provided under a more general integrated natural resource 
management strategy at these and other DOD installations.

State Laws Affecting the Coastal California Gnatcatcher

    The coastal California gnatcatcher is designated as a Species of 
Special Concern by the California Department of Fish and Wildlife 
(CDFW) (CDFG 2008). Although this designation is administrative and 
provides no formal legal status for protection, it is intended to 
highlight those species at conservation risk to State and Federal and 
local governments, land managers, and others, as well as to encourage 
research for those species whose life history and population status are 
poorly known (Comrack et al. 2008, p. 2).

California Environmental Quality Act (CEQA)

    CEQA (California Public Resources Code 21000-21177) is the 
principal statute mandating environmental assessment of projects in 
California. The purpose of CEQA is to evaluate whether a proposed 
project may have an adverse effect on the environment and, if so, to 
determine whether that effect can be reduced or eliminated by pursuing 
an alternative course of action, or through mitigation. CEQA applies to 
certain activities of State and local public agencies; a public agency 
must comply with CEQA when it undertakes an activity defined under CEQA 
as a ``project.''
    As with NEPA, CEQA does not provide a direct regulatory role for 
the CDFW or other State and local agencies relative to activities that 
may affect the coastal California gnatcatcher. However, CEQA requires a 
complete assessment of the potential for a proposed project to have a 
significant adverse effect on the environment. Among the conditions 
outlined in the CEQA Guidelines that may lead to a mandatory finding of 
significance are where the project ``has the potential to . . . 
substantially reduce the habitat of a fish or wildlife species; cause a 
fish or wildlife population to drop below self-sustaining levels; 
threaten to eliminate a plant or animal community; [or] substantially 
reduce the number or restrict the range of an endangered, rare or 
threatened species'' (title 14 of the California Code of Regulations 
(CCR), Sec.  15065(a)(1)). The CEQA Guidelines further state that a 
species ``not included in any listing [as threatened or endangered] 
shall nevertheless be considered to be endangered, rare, or threatened, 
if the species can be shown to meet the criteria'' for such listing (14 
CCR 15380(d)). In other words, CEQA would require any project that may 
impact populations of these species to assess and disclose such 
potential impacts during the environmental review process (Osborn 2015, 
pers. comm.).

The Natural Community Conservation Planning (NCCP) Act

    The NCCP program is a cooperative effort between the State of 
California and numerous private and public partners with the goal of 
protecting habitats and species. The NCCP program identifies and 
provides for the regional or area-wide protection of plants, animals, 
and their habitats while allowing compatible and appropriate economic 
activity. The program uses an ecosystem approach to planning for the 
protection and continuation of biological diversity (https://www.wildlife.ca.gov/Conservation/Planning/NCCP). Regional NCCPs provide 
protection to federally listed and other covered species by conserving 
native habitats upon which the species depend. NCCPs are usually 
developed in conjunction with habitat conservation plans (HCPs) 
prepared pursuant to the Act.
    The 2010 5-year review discusses the NCCP program in greater 
detail. Currently, the following NCCP plans that cover the coastal 
California gnatcatcher are approved and being implemented: Multiple 
Species Conservation Program (one of four Subregional Plans in San 
Diego County with 5 of 11 Subarea Plans approved),

[[Page 59972]]

San Diego County Water Authority NCCP/HCP, San Diego Gas & Electric 
NCCP, San Diego Multiple Habitat Conservation Program (a second 
Subregional Plan in San Diego County with 1 of 6 Subarea Plans 
approved), Western Riverside County Multiple Species Habitat 
Conservation Plan (Western Riverside County MSHCP), and Orange County 
Central/Coastal NCCP/HCP (CDFW 2015, pp. 12 and 13). Additionally, the 
Orange County Transportation Authority M2 NCCP/HCP in Orange County and 
the Rancho Palos Verdes NCCP/HCP in Los Angeles County are nearing 
completion. The North County Multiple Species Conservation Plan and the 
East County Multiple Species Conservation Plan (CDFW 2015, pp. 12 and 
13), the third and fourth Subregional Plans in San Diego County, are 
still in the development phase. Finally, the Orange County Southern 
Subregion HCP is not approved as an NCCP, but this plan is a regionally 
significant Service-approved HCP that includes core populations of the 
coastal California gnatcatcher and large expanses of coastal sage 
scrub.
    These plans provide a comprehensive, habitat-based approach to the 
protection of covered species, including the coastal California 
gnatcatcher, by focusing on lands identified as important for the long-
term conservation of the covered species and through the implementation 
of management actions for conserving those lands. These protections are 
outlined in the management actions and conservation objectives 
described within each plan. However, because the total habitat 
protection associated with these plans is not expected until plans are 
fully implemented, and because not all areas are covered, habitat loss 
is still impacting the gnatcatcher and is expected to continue into the 
future.
    In our 2010 5-year review, we estimated that 59 percent of modeled 
coastal California gnatcatcher habitat in the United States would be 
conserved with full implementation of currently permitted, long-term 
Regional NCCP/HCPs (Service 2010, p. 15). We reviewed the most 
currently available reports for four regional NCCP/HCPs and one HCP to 
determine the amount of coastal sage scrub habitat that has been 
conserved as of the date of the respective final reports:
     For the San Diego County MSCP (City of San Diego, County 
of San Diego, City of Chula Vista, City of Poway, and City of La Mesa), 
the total number of acres of coastal sage scrub habitat conserved both 
inside and outside the preserve planning area is 49,871 ac (20,182 ha); 
conserved habitat inside the preserve planning area is approximately 
42,129 ac (17,049 ha) or about 68 percent of the plan's target (City of 
Chula Vista 2015, p. 35; City of San Diego 2015, p. 15; County of San 
Diego 2015, p. 51).
     For the San Diego County MSCP, the City of Carlsbad 
reported 1,683 ac (681 ha) of coastal sage scrub conserved within their 
Habitat Management Preserve system as of December 2015 (84 percent of 
target) (Grim 2016, pers. comm.).
     For the Orange County Central--Coastal NCCP/HCP (as of the 
end of 2013), the amount of coastal sage scrub conserved is 17,809 ac 
(7,207 ha) (Nature Reserve of Orange County 2013).
     For the Western Riverside County MSHCP, the Western 
Riverside County Regional Conservation Authority (WRCRCA 2015, pp. 3-
9--3-10) reported that 11,802 ac (4,776 ha) of coastal sage scrub was 
conserved from February 2000 to December 31, 2013.
    With the addition of the Orange County Southern Subregion HCP, 
which reported coastal California gnatcatcher scrub habitat of 13,135 
ac (5,315 ha) within reserves as of December 2013 (Rancho Mission Viejo 
2013), the total number is approximately 86,558 ac (35,028 ha) of 
coastal sage scrub conserved (within reserves established by these 
plans). This amount represents about 47 percent of the total target 
(182,976 ac (74,048 ha)) of coastal California gnatcatcher habitat to 
be preserved by the five plans described in our 2010 5-year review 
(Service 2010, p. 15).
    In summary, while conservation is anticipated to continue within 
existing plan boundaries within the U.S. range of the coastal 
California gnatcatcher, habitat protection occurs in a step-wise 
fashion as areas are conserved, and the total habitat protection 
associated with a plan is not expected until plans are fully 
implemented. Once the plans are fully implemented upon completion of 
the permits (which last for 50-75 years), the plans would provide 
conservation for much of the 56 percent of the coastal California 
gnatcatcher's range in the United States. However, the 44 percent of 
the subspecies range in Baja California is not subject to protections 
provided by NCCP/HCP plans. Therefore, the subspecies and its habitat 
remain susceptible to urban development and associated threats.
    Without the protections provided to the subspecies and its habitat 
under the Act (that is, if the coastal California gnatcatcher was 
delisted), the current NCCP/HCPs may provide some ancillary benefits to 
the subspecies given that other federally listed species of plants and 
animals covered under these plans are also found within coastal sage 
scrub habitat (for example, Quino checkerspot butterfly (Euphydrays 
editha quino)). By continuing to implement the plans, the permittees 
would retain incidental take coverage for these other species. However, 
permittees under these regional plans could request permit 
modifications or request that their long-term permits be renegotiated 
should the coastal California gnatcatcher be delisted under the Act. 
Similarly, the NCCP/HCPs currently under development in southern 
California would likely require reevaluation. However, all conservation 
already implemented would continue to provide benefits to the coastal 
California gnatcatcher even if it was delisted. Because conservation 
and management for the coastal California gnatcatcher has not yet been 
fully implemented under the NCCP/HCPs in place and some NCCP/HCPs are 
not yet developed, all of the potential conservation anticipated under 
these plans is not yet fully assured absent the protections of the Act.

Regulatory Mechanisms in Mexico

    As described above (see Urban and Agricultural Development 
section), we recently estimated that approximately 1,704,406 ac 
(689,749 ha) of coastal sage scrub habitat remains in Baja California 
from 30 [deg]N. to the United States-Mexico border (Service 2016a).
    The Mexican Government recognizes the atwoodi subspecies of the 
California gnatcatcher (see taxonomic classification of Mellink and Rea 
1994, pp. 59-62); Mellink and Rea (1994, p. 55) described Polioptila 
californica atwoodi as a new subspecies of California gnatcatcher from 
northwestern Baja California, Mexico. They defined a range for this 
novel subspecies as ``from Rio de las Palmas and Valle de las Palmas 
(30 km SE. of Tijuana) in the interior and at least Punta Banda along 
the coast south to Arroyo El Rosario, 32 to 30 [deg]N.'' within coastal 
sage scrub and maritime succulent scrub plant communities (Mellink and 
Rea 1994, p. 55); this distribution mostly overlaps with what the 
Service considers to be the listed gnatcatcher subspecies (58 FR 16742; 
March 30, 1993).
    This entity is listed as threatened under Mexico's NORMA Oficial 
Mexicana NOM-059-SEMARNAT-2010, Environmental Protection--Species of 
Wild Flora and Fauna Native to Mexico (Protecci[oacute]n ambiental--
Especies nativas de M[eacute]xico de flora y fauna silvestres--
Categor[iacute]as de riesgo y

[[Page 59973]]

especificaciones para su inclusi[oacute]n, exclusi[oacute]n o cambio--
Lista de especies en riesgo) (SEMARNAT 2010). Threatened species are 
defined under Mexican law as those which may be ``in danger of 
disappearing in the short or medium term'' if factors that adversely 
affect their viability, such as deterioration or modification of 
habitat, or directly reduce the size of their populations, continue to 
operate (SEMARNET 2010, p. 5). However, enforcement of this law 
generally depends upon an individual or a groups' willingness to modify 
proposed projects rather than the legal protections provided under the 
law (Hinojosa 2008, pers. comm.). Monitoring of compliance with this 
law is the responsibility of the Secretaria de Medio Ambiente y 
Recursos Naturales through its established entities. We do not have 
further information regarding the effectiveness of this law for 
protecting the coastal California gnatcatcher and its habitat.
    In Mexico, the development of state and municipal plans is designed 
to regulate and control land use and various production activities as 
well as provide environmental protections and preservation and 
sustainability of natural resources (Conservation Biology Institute 
2004, p. 31). As an example, an ordenamiento ecol[oacute]gico 
(ecological regulation/zoning ordinance) is being developed for the 
City of Tijuana to identify [aacute]reas verdes (important natural 
resource areas), and the ordenamiento will be used to guide land 
development within Tijuana (Conservation Biology Institute 2004, p. 
31). Other State and Federal environmental laws in Mexico include Ley 
General del Equilibrio Ecol[oacute]gico y la Protecci[oacute]n al 
Ambiente and Ley de Protecci[oacute]n al Ambiente para el Estado de 
Baja California, which require the preparation of an environmental 
impact study (manifestaci[oacute]n de impacto ambiental) for any 
development project; if the project is determined to result in negative 
environmental impacts, the developer must undertake mitigation actions 
to minimize these impacts and/or restore natural conditions 
(Conservation Biology Institute 2004, p. 31).

Existing Regulatory Mechanisms Summary

    Outside of the Act, few Federal conservation management and 
conservation measures exist throughout the U.S. range of the coastal 
California gnatcatcher that provide protections to the subspecies and 
its habitat. State management and conservation measures are limited 
primarily to the planning and implementation of the NCCP Act, and there 
is uncertainty as to whether the regional plans would continue to 
provide the full conservation benefits anticipated should the 
subspecies be delisted under the Act. Limited protection is provided to 
the coastal California gnatcatcher through the inclusion of its 
designation as a Species of Special Concern within State (CEQA) 
planning processes.
    Based on the best available data, the listing of the atwoodi 
subspecies of the California gnatcatcher by the Mexican Government 
provides a limited level of protection or conservation benefit to the 
atwoodi populations found in Baja California. Comprehensive reserve 
areas for coastal sage scrub and chaparral vegetation have not been 
established in northern Baja California. While existing Mexican 
regulatory mechanisms may provide some protection for the subspecies, 
we lack information on implementation of those mechanisms specifically 
related to protection of the coastal California gnatcatcher, protection 
of habitat, and abatement of threats.
    Therefore, although regulatory mechanisms are in place and provide 
some protection to the coastal California gnatcatcher and its habitat 
throughout its range, absent the protections of the Act (for example, 
section 7, section 9, and section 10(a)(1)(B)), these mechanisms would 
provide substantially less protection from the stressors currently 
acting on the subspecies such as urban and agricultural development. 
Moreover, some of the threats faced by the species and its habitat, 
including wildland fire, vegetation type conversion, and fragmentation, 
are not readily susceptible to amelioration through regulatory 
mechanisms.

Cumulative Effects

    Threats can work in concert with one another to cumulatively create 
conditions that may impact the coastal California gnatcatcher or its 
habitat beyond the scope of each individual threat. The best available 
data indicate that cumulative impacts are currently occurring from the 
combined effects of a number of stressors, including vegetation type 
conversion, wildland fire, and the effects of climate change.
    These stressors interact in multiple ways. As discussed in the 
Wildand Fire section above, the wildland fire-type conversion feedback 
loop promotes the degradation and eventual loss of coastal California 
gnatcatcher habitat, especially on a local scale where there are short 
intervals between fires (Service 2010, pp. 15-18). The effects 
associated with climate change have the potential to further contribute 
to the vegetation type conversion process, though it is not yet clear 
how climate change will interact with the ongoing conversion of coastal 
sage scrub to nonnative grasses and other vegetation types unsuitable 
for use by the coastal California gnatcatcher. It is also unclear 
whether it will increase or decrease the rate of change.
    Furthermore, based on our analysis of the best available data, it 
is likely that the native plant communities that support the coastal 
California gnatcatcher in southern California are presently impacted by 
the cumulative effects of wildland fire and the warming effects of 
climate change. Yue et al. (2014, entire) developed projections of 
wildfire activity in southern California at mid-century (2016-2065) 
using the IPCC's A1B scenario (moderate growth in fossil fuel emissions 
in the first half of the 21st century but with a gradual decrease after 
2050). Using regression models, the study found a likely doubling of 
area burned in southwestern California by midcentury, while 
parameterization models indicate a likely increase of 40 percent in 
this region under this IPCC scenario (Yue et al. 2014, p. 1,973). The 
analysis was unique in that the models considered the effects of future 
patterns of Santa Ana wind events. It indicates that a projected 
midcentury increase in November Santa Ana wind events will contribute 
to the increased area burned at that time of year (Yue et al. 2014, p. 
1,990). The authors conclude that the results suggest that wildfire 
activity will likely increase in southwestern California due to rising 
surface temperatures (Yue et al. 2014, p. 1,989).
    Stavros et al. (2014, entire) developed regional projections of the 
probability of very large wildland fires (defined as greater than or 
equal to 50,000 ac (20,234 ha)) under various climate change scenarios 
for the western United States. Their model results found a significant 
increase in the likelihood and frequency of very large fires for 
climate regimes projected in 2031-2060, relative to 1950-2005, in 
almost all areas, including southern California (Stavros et al. 2014, 
p. 460). These impacts are expected to continue into the future (to the 
2060s based on climate change projections).
    The climate change-wildland fire connection will likely result in a 
reduction in the amount of suitable habitat for the coastal California 
gnatcatcher and will likely lead to a greater chance of vegetation type 
conversion that degrades and eventually eliminates coastal California 
gnatcatcher

[[Page 59974]]

habitat. Moreover, these stressors, working singly or in combination, 
are operating at a landscape scale. These stressors may affect large 
areas and may not be addressed by current management plans. Thus, in 
the absence of management to counteract the identified effects, these 
stressors are contributing to the habitat-degradation and type-
conversion continuum that is occurring throughout the range of the 
subspecies. Therefore, as summarized above and as described in our 2010 
5-year review, the best available data indicate that the cumulative 
effects of vegetation type conversion, wildland fire, and climate 
change will continue to act as a high-level stressor on the coastal 
California gnatcatcher and its habitat now and into the future.

Finding

    In making this finding, we have followed the procedures set forth 
in section 4(a)(1) of the Act and regulations implementing the listing 
provisions of the Act in 50 CFR part 424. We reviewed the petition, 
information available in our files, and other available published and 
unpublished information. We sought input from subject matter experts 
and other Federal, State, and Tribal agencies. On the basis of the best 
scientific and commercial information available, we find that the 
petitioned action to delist the coastal California gnatcatcher is not 
warranted. Review of the best available scientific and commercial data 
did not show that the original determination, made at the time the 
species was classified as threatened in 1993, is now in error. Rather, 
using a multi-evidence criteria approach, the best available scientific 
and commercial data supports the coastal California gnatcatcher as a 
valid (distinguishable) subspecies.
    For the purposes of our status review, as required by the Act, we 
considered the five factors in assessing whether the coastal California 
gnatcatcher is endangered or threatened throughout all of its range. In 
our threats analysis, we examined the best scientific and commercial 
information available regarding the past, present, and foreseeable 
future threats faced by the subspecies. We reviewed the information 
available in our files, information submitted by the public in response 
to our 90-day finding (79 FR 78775; December 31, 2014), and other 
available published and unpublished information. As described above in 
Background, the petitioners did not provide any new information on any 
of the factors. Based on our review of the best available scientific 
and commercial information, we find that the current and future threats 
are of sufficient imminence, intensity, or magnitude to indicate that 
the coastal California gnatcatcher remains likely to become an 
endangered species within the foreseeable future throughout all of its 
range. Therefore, the coastal California gnatcatcher currently meets 
the definition of a threatened species.
    We evaluated each of the potential stressors discussed in the 2010 
5-year review (Service 2010, entire), and we determined the following 
factors have impacted the coastal California gnatcatcher and its 
habitat or may affect gnatcatcher individuals or populations in the 
future: Urban and agricultural development (Factor A), grazing (Factor 
A), wildland fire (Factor A and Factor E), vegetation type conversion 
(Factor A), climate change (Factor A and Factor E), disease (Factor C), 
predation (Factor C), fragmentation (Factor A and Factor E), and brood 
parasitism (Factor E). Disease (Factor C) and predation (Factor C) are 
having only local, small-scale impacts to the coastal California 
gnatcatcher and its habitat throughout its range; therefore, we do not 
consider disease or predation to be threats at this time.
    Additionally, though brood parasitism (Factor E) is affecting 
individual coastal California gnatcatcher pairs throughout the species' 
range, the impacts in the United States are being reduced through 
available regulatory mechanisms and implementation of conservation 
measures, such as regional NCCP/HCP management plans and section 
10(a)(1)(A) permits. Furthermore, the ability of the coastal California 
gnatcatcher to re-nest multiple times in one breeding season helps it 
to be resilient to brood parasitism by brown-headed cowbirds. 
Therefore, we do not find that brood parasitism poses a threat to the 
coastal California gnatcatcher at the present time, nor do we expect it 
to become a threat in the foreseeable future.
    At this time, impacts from urban and agricultural development 
(Factor A) continue to be a medium- to high-level stressor for the 
coastal California gnatcatcher and its habitat. Implementation of 
existing HCPs and the ongoing development of additional NCCP/HCPs have 
significantly reduced the impacts of urban development to coastal 
California gnatcatcher habitat in the United States; however, none of 
the regional plans are fully implemented. We estimated that these plans 
encompass approximately 55 percent of coastal sage scrub habitat and 
that approximately 47 percent of the plans' conservation targets have 
been reached (Service 2016a), for a total of 28 percent of habitat 
conserved overall in the U.S. range of the subspecies by NCCP/HCP 
plans. Though we anticipate that additional habitat will be conserved 
with full implementation of the existing plans, total conservation of 
the areas identified within the plans is not expected until the plans 
are fully implemented. Overall, 49 percent of coastal sage scrub in the 
United States has no mechanism preventing conversion of the habitat for 
urban or agricultural uses (Service 2016a), and Mexico has few areas of 
coastal sage scrub protected from development. Therefore, though 
substantial progress has been made since the time of listing to 
conserve habitat that supports the coastal California gnatcatcher, we 
find that urban and agricultural development continues to pose a threat 
to the coastal California gnatcatcher and its habitat.
    Though grazing (Factor A) is having only low-level impacts to 
coastal California gnatcatcher habitat in the United States, grazing in 
coastal scrub habitat in Mexico can still result in vegetation type 
conversion, and land clearing for grazing purposes has been documented 
within northern Baja California. Therefore, we find that grazing is 
posing a threat to the subspecies' habitat in Mexico, though habitat 
impacts can be temporary.
    Wildland fire (Factor A and Factor E) was identified as a threat to 
the coastal California gnatcatcher and its habitat both at the time of 
listing and in our 2010 5-year review. Based on our analysis, although 
currently established NCCP/HCPs provide for the establishment of 
coastal sage scrub reserves and include fire management as one of their 
primary objectives, there is no mechanism or conservation measure that 
can fully prevent the recurrence of natural or human-caused destructive 
wildland fires in coastal California gnatcatcher habitat. Therefore, we 
find that wildland fire poses a threat to the coastal California 
gnatcatcher and its habitat throughout the range of the species and 
that this threat will continue to cause impacts into the foreseeable 
future.
    Vegetation type conversion (Factor A) of coastal sage scrub to 
nonnative grasslands is ongoing throughout the range of the coastal 
California gnatcatcher. Effects of type conversion are currently being 
reduced through habitat management by NCCP/HCPs; however, management 
plans for each reserve area are not yet complete, and maintaining 
adequate funding for perpetual management of the reserves is a 
challenge common to all regional NCCP/HCPs. Therefore, vegetation type 
conversion is posing a threat to the

[[Page 59975]]

coastal California gnatcatcher and its habitat, and we expect that 
these impacts will continue into the foreseeable future.
    Climate change (Factor A and Factor E) is a low- to medium-level 
stressor that is anticipated to result in shifts to the distribution of 
the subspecies' habitat and that may potentially affect gnatcatchers at 
the individual or population level into the foreseeable future. 
However, the impacts from climate change are not well understood and 
under some projections may increase habitat for the species as coastal 
sage scrub moves to higher elevations, though the impacts from climate 
change on its own are not fully understood. Therefore, while impacts of 
climate change are not fully understood, climate change is considered a 
low- to moderate-level threat that may affect the distribution of the 
subspecies and its habitat in the future.
    New information we have received since the 2010 5-year review 
suggests that fragmentation (Factor A and Factor E) at small geographic 
scales is a threat of lower magnitude than was described at the time of 
listing. However, the effects of fragmentation are more significant at 
large geographic (landscape) scales than previously recognized for 
those coastal California gnatcatcher populations that have become 
widely separated due to urban development and other habitat losses or 
modifications (such as wildland fire). Therefore, we find that 
fragmentation still poses a threat to portions of the coastal 
California gnatcatcher subspecies, and we expect that these impacts 
will continue into the foreseeable future.
    Furthermore, cumulative impacts from climate change and other 
factors such as vegetation type conversion and wildland fire have the 
potential to significantly alter habitat that currently supports the 
coastal California gnatcatcher. The wildland fire-type conversion 
feedback loop promotes the degradation and eventual loss of coastal 
California gnatcatcher habitat, particularly given the increase in fire 
frequency from the historical fire regime. Recent studies (such as 
Stavros et al. 2014) indicate that with climate change, fire frequency 
and intensity may continue to increase, which would in turn increase 
the wildland fire-type conversion feedback loop. The effects associated 
with climate change have the potential to further contribute to the 
vegetation type conversion process, though the exact impacts to coastal 
sage scrub habitat are unknown. Therefore, we find that cumulative 
impacts of multiple stressors are a threat to the coastal California 
gnatcatcher, and that this threat is likely to continue at the same 
level or increase into the foreseeable future.
    Available regulatory mechanisms, such as the combined NCCP/HCP 
program and INRMPs on local military bases are providing important 
protections that help reduce the threats affecting the coastal 
California gnatcatcher and its habitat, such as urban development, 
vegetation type conversion, and fragmentation. Absent the provisions of 
the Act, some of these protections would no longer be in place. In 
Mexico, the listing of the atwoodi subspecies of the California 
gnatcatcher provides only a limited level of protection or conservation 
benefit, and comprehensive reserve areas for coastal California 
gnatcatcher habitat have not been established in northern Baja 
California. Therefore, absent the protections of the Act, existing 
regulatory mechanisms would provide substantially less protection from 
the threats currently acting on the subspecies.
    Moreover, some of the threats faced by the coastal California 
gnatcatcher, such as wildland fire, vegetation type conversion, and 
habitat fragmentation, cannot be readily ameliorated through the 
application of regulatory mechanisms. Therefore, we conclude that the 
best available scientific and commercial information indicates that 
these threats are continuing to impact the subspecies and its habitat 
throughout its range, and that these impacts will continue into the 
foreseeable future. At this time, many threats are being reduced 
through existing regulatory mechanisms, and we expect that full 
implementation of regional NCCPs/HCPs will provide protection to much 
of the coastal sage scrub habitat that supports the coastal California 
gnatcatcher. However, many areas are not yet protected by existing 
plans and other plans are still in development.
    Furthermore, many threats remain on the landscape that are not 
fully managed, and the best available scientific and commercial 
information indicates that these threats are likely to continue, such 
that the coastal California gnatcatcher is likely to become an 
endangered species within the foreseeable future throughout all its 
range. Because we have determined that the coastal California 
gnatcatcher is likely to become an endangered species throughout all 
its range within the foreseeable future, no portion of its range can be 
``significant'' for purposes of the Act's definitions of ``endangered 
species'' and ``threatened species.'' See the Service's final policy 
interpreting the phrase ``significant portion of its range'' (SPR) (79 
FR 37578; July 1, 2014). Therefore, we find that the coastal California 
gnatcatcher continues to meet the definition of a threatened species 
under the Act, but that the threats are not severe enough at this time 
such that the species is in danger of extinction throughout its range. 
Therefore, we find that reclassification to an endangered species is 
not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, the coastal California gnatcatcher to our 
Carlsbad Fish and Wildlife Office (see ADDRESSES) whenever it becomes 
available. New information will help us monitor the subspecies and 
encourage additional conservation actions.

References Cited

    A complete list of references cited is available on the Internet at 
https://www.regulations.gov in Docket Number FWS-R8-ES-2014-0058 and 
upon request from the Carlsbad Fish and Wildlife Office (see 
ADDRESSES).

Author(s)

    The primary author(s) of this notice are the staff members of the 
Carlsbad Fish and Wildlife Office and Pacific Southwest Regional 
Office.

Authority

    The authority for this action is section 4 of the Endangered 
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: August 15, 2016.
Stephen Guertin,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2016-20864 Filed 8-30-16; 8:45 am]
BILLING CODE 4333-15-P