# Endangered and Threatened Wildlife and Plants; Endangered Species Status for Rim Rock Crowned Snake and Key Ring-Necked Snake and Designation of Critical Habitat

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2022-21543

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** October 14, 2022
- **Citation:** 87 FR 62614

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2022-0022; FF09E21000 FXES1111090FEDR 223]
RIN 1018-BE84
Endangered and Threatened Wildlife and Plants; Endangered Species Status for Rim Rock Crowned Snake and Key Ring-Necked Snake and Designation of Critical Habitat

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Proposed rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), propose to list two Florida species, the Key ring-necked snake (
Diadophis punctatus acricus
) and the rim rock crowned snake (
Tantilla oolitica
), and propose to designate critical habitat under the Endangered Species Act of 1973, as amended (Act). This determination also serves as our 12-month finding on the petition to list the Key ring-necked snake and the rim rock crowned snake. After a review of the best available scientific and commercial information, we find that listing both species is warranted. Accordingly, we propose to list both species as endangered species under the Act. If we finalize this rule as proposed, it would add the species to the List of Endangered and Threatened Wildlife and extend the Act's protections to both species. We also propose to designate critical habitat for the Key ring-necked snake and the rim rock crowned snake under the Act. In total, approximately 2,604 acres (ac) (1,054) hectares (ha) in Monroe County, Florida, and approximately 5,972 ac (2,418 ha) in Miami-Dade County and Monroe County, Florida, fall within the boundaries of the proposed critical habitat designation for the Key ring-necked snake and the rim rock crowned snake, respectively. We announce the availability of a draft economic analysis of the proposed designation of critical habitat for both species.

DATES:

We will accept comments received or postmarked on or before December 13, 2022. Comments submitted electronically using the Federal eRulemaking Portal (see
ADDRESSES
, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for a public hearing, in writing, at the address shown in
FOR FURTHER INFORMATION CONTACT
by November 28, 2022.

ADDRESSES:

You may submit comments by one of the following methods:

(1)
Electronically:
Go to the Federal eRulemaking Portal:
https://www.regulations.gov.
In the Search box, enter FWS-R4-ES-2022-0022, which is the docket number for this rulemaking. Then, click on the Search button. On the resulting page, in the Search panel on the left side of the screen, under the Document Type heading, check the Proposed Rule box to locate this document. You may submit a comment by clicking on “Comment.”

(2)
By hard copy:
Submit by U.S. mail to: Public Comments Processing, Attn: FWS-R4-ES-2022-0022, U.S. Fish and Wildlife Service, MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.

We request that you send comments only by the methods described above. We will post all comments on
https://www.regulations.gov.
This generally means that we will post any personal information you provide us (see Information Requested, below, for more information).

Availability of supporting materials:
For the proposed critical habitat designation, the coordinates or plot points or both from which the maps are generated are included in the decision file and are available at
https://www.fws.gov/office/florida-ecological-services
and at
https://www.regulations.gov
under Docket No. FWS-R4-ES-2022-0022. Additional supporting information that we developed for this proposed rule will be available on the Service's website, at
https://www.regulations.gov,
or both.

FOR FURTHER INFORMATION CONTACT:

Lourdes Mena, Division Manager, Classification and Recovery, Florida Ecological Services Field Office, 7915 Baymeadows Way, Suite 200, Jacksonville, FL 32256-7517;
lourdes_mena@fws.gov;
telephone 904-731-3134. Individuals in the United States who are deaf, deafblind, hard of hearing, or have a speech disability may dial 711 (TTY, TDD, or TeleBraille) to access telecommunications relay services. Individuals outside the United States should use the relay services offered within their country to make international calls to the point-of-contact in the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule.
Under the Act, a species warrants listing if it meets the definition of an endangered species (in danger of extinction throughout all or a significant portion of its range) or a threatened species (likely to become endangered within the foreseeable future throughout all or a significant portion of its range). If we determine that a species warrants listing, we must list the species promptly and designate the species' critical habitat to the maximum extent prudent and determinable. We have determined that the Key ring-necked snake and the rim rock crowned snake both meet the Act's definition of an endangered species; therefore, we are proposing to list them as such and are proposing a designation of critical habitat for both species. Both listing a species as an endangered or threatened species and designating critical habitat can be completed only by issuing a rule through the Administrative Procedure Act rulemaking process.

What this document does.
We propose to list both the Key ring-necked snake and the rim rock crowned snake as endangered species under the Act, and we propose to designate critical habitat for both species.

The basis for our action.
Under the Act, we may determine that a species is an endangered or threatened species because of any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence. We have determined that the Key ring-necked snake and the rim rock crowned snake are facing threats due to development (Factor A), fire suppression (Factor A), and effects associated with climate change, particularly sea level rise and saltwater intrusion (Factor E).

Section 4(a)(3) of the Act requires the Secretary of the Interior (Secretary) to designate critical habitat concurrent with listing to the maximum extent prudent and determinable. Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protections; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 4(b)(2) of the Act states that the Secretary must make the designation on the basis of the best scientific data

available and after taking into consideration the economic impact, the impact on national security, and any other relevant impacts of specifying any particular area as critical habitat.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other governmental agencies, Native American Tribes, the scientific community, industry, or any other interested parties concerning this proposed rule.

We particularly seek comments concerning:

(1) The species' biology, range, and population trends, including:

(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range, including distribution patterns;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, their habitats, or both.

(2) Factors that may affect the continued existence of the species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.

(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and existing regulations that may be addressing those threats.

(4) Additional information concerning the historical and current status, range, distribution, and population size of these species, including the locations of any additional populations of these species.

(5) Information on the immediacy and magnitude of threats to the rim rock crowned snake in the upper and lower Florida Keys.

(6) Whether we should consider evaluating populations of the rim rock crowned snake as distinct population segments.

(7) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531
et seq.
), including information regarding the following factors that the regulations identify as reasons why designation of critical habitat may be not prudent:

(a) The species are threatened by taking or other human activity and identification of critical habitat can be expected to increase the degree of such threat to the species; or

(b) Such designation of critical habitat would not be beneficial to the species. In determining whether a designation would not be beneficial, the factors the Services may consider include but are not limited to: Whether the present or threatened destruction, modification, or curtailment of a species' habitat or range is not a threat to the species, or whether any areas meet the definition of “critical habitat.”

(8) Specific information on:

(a) The amount and distribution of Key ring-necked snake and rim rock crowned snake habitat;

(b) Any additional areas occurring within the range of the species that should be included in the designation because they (1) are occupied at the time of listing and contain the physical or biological features that are essential to the conservation of the species and that may require special management considerations, or (2) are unoccupied at the time of listing and are essential for the conservation of the species.

(c) For areas not occupied at the time of listing that may be essential for the conservation of the species, we particularly seek comments on whether any additional unoccupied areas should be designated for either species. For the rim rock crowned snake, we ask for information on areas in the Environmentally Endangered Lands (EEL) program in Miami-Dade County that may be essential to the conservation of the rim rock crowned snake. For the Key ring-necked snake, we request information or additional survey data to determine whether we should designate unoccupied critical habitat on Key West for the Key ring-necked snake; and

(d) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change.

(9) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.

(10) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation, and the related benefits of including or excluding specific areas.

(11) Information on the extent to which the description of probable economic impacts in the draft economic analysis (DEA) is a reasonable estimate of the likely economic impacts and any additional information regarding probable economic impacts that we should consider.

(12) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act. Specific information we seek includes the effectiveness of the Monroe County habitat conservation plan (HCP) in protecting pine rocklands and rockland hammock habitat and in providing for conservation of the Key ring-necked snake and the rim rock crowned snake.

(13) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include. If you request exclusion of a particular area or areas from the final designation, please provide information regarding the existence of a meaningful economic or other relevant impact supporting the benefit of exclusion of that particular area.

Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information, although noted, do not provide substantial information necessary to support a determination. Section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or a threatened species must be made solely on the basis of the best scientific and commercial data available, and section 4(b)(2) of the Act directs that the Secretary shall designate critical habitat on the basis of the best scientific data available.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in
ADDRESSES
. We request that you send comments only by the methods described in
ADDRESSES
.

If you submit information via
https://www.regulations.gov,
your entire submission—including any personal identifying information—will be posted on the website. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot

guarantee that we will be able to do so. We will post all hardcopy submissions on
https://www.regulations.gov.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on
https://www.regulations.gov.

Because we will consider all comments and information we receive during the comment period, our final determinations may differ from this proposal. Based on the new information we receive (and any comments on that new information), we may conclude that either or both species are threatened instead of endangered, or we may conclude that either or both species do not warrant listing as either endangered species or threatened species. For critical habitat, our final designation may not include all areas proposed, may include some additional areas that meet the definition of critical habitat, or may exclude some areas if we find the benefits of exclusion outweigh the benefits of inclusion.

Public Hearing

Section 4(b)(5) of the Act provides for a public hearing on this proposal, if requested. Requests must be received by the date specified in
DATES
. Such requests must be sent to the address shown in
FOR FURTHER INFORMATION CONTACT
. We will schedule a public hearing on this proposal, if requested, and announce the date, time, and place of the hearing, as well as how to obtain reasonable accommodations, in the
Federal Register
and local newspapers at least 15 days before the hearing. We may hold the public hearing in person or virtually via webinar. We will announce any public hearing on our website, in addition to the
Federal Register
. The use of these virtual public hearings is consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

Both the Key ring-necked snake and the rim rock crowned snake were included as Category 2 candidate species in our December 30, 1982 (47 FR 58454), September 18, 1985 (50 FR 37958), January 6, 1989 (54 FR 554), November 21, 1991 (56 FR 58804), and November 15, 1994 (59 FR 58982), candidate notices of review (CNORs). Category 2 included taxa for which information in our possession indicated that a proposed listing rule was possibly appropriate, but for which sufficient data on biological vulnerability and threats were not available to support a proposed rule.

In the CNOR published on February 28, 1996 (61 FR 7596), we announced a revised list of plant and animal taxa that were regarded as candidates for possible addition to the Lists of Endangered and Threatened Wildlife and Plants. The revised candidate list included only former Category 1 species. Former Category 2 species were removed from the candidate list in order to reduce confusion about the conservation status of these species and to clarify that we no longer regarded these species as candidates for listing. Since both the Key ring-necked snake and the rim rock crowned snake were Category 2 species, they were no longer recognized as candidate species as of the publication of the February 28, 1996, CNOR.

On July 11, 2012, we received a petition from the Center for Biological Diversity requesting that 53 species of reptiles and amphibians, including the Key ring-necked snake and the rim rock crowned snake, be listed as endangered or threatened and critical habitat be designated under the Act.

On July 1, 2015, we published a 90-day finding (80 FR 37568) that the petition presented substantial scientific or commercial information indicating that the petitioned action may be warranted for both the Key ring-necked snake and the rim rock crowned snake. This proposed rule constitutes our 12-month petition finding for both species.

Supporting Documents

A species status assessment (SSA) team prepared SSA reports for both the Key ring-necked snake and the rim rock crowned snake (Service 2021a, entire; Service 2021b, entire). The SSA teams were composed of Service biologists, in consultation with other species experts. The SSA reports represent a compilation of the best scientific and commercial data available concerning the status of the species, including the impacts of past, present, and future factors (both negative and beneficial) affecting the species. In accordance with our joint policy on peer review published in the
Federal Register
on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review of listing actions under the Act, we sent the Key ring-necked snake SSA report to five independent peer reviewers for review, including scientists with expertise in wildlife biology, herpetology, and conservation biology. We received two responses. We sent the rim rock crowned snake SSA report to five independent peer reviewers, including scientists with expertise in wildlife biology, herpetology, and conservation biology. We received three responses.

I. Proposed Listing Determination

Background

Key Ring-Necked Snake

A thorough review of the taxonomy, life history, and ecology of the Key ring-necked snake (
Diadophis punctatus acricus
) is presented in the SSA report (version 1.0; Service 2021a, pp. 2-5). The Key ring-necked snake is one of 14 distinct subspecies of ring-necked snakes in North America, all of which are subspecies of
D. punctatus.
It is one of the smallest subspecies of the Family Dipsadidae; an adult specimen will average between 6 and 10 inches (in) (15.2 to 25.4 centimeters (cm)). A recent review of phylogenetic data supports the current subspecies classification for the Key ring-necked snake (Hoffman 2019, entire).

This slender snake has a pale grayish-brown head; a grayish-black dorsal surface; and a yellow, orange, or bright red abdomen which fades to orange/red underneath the tail (Florida Fish and Wildlife Conservation Commission (FWC) 2013, p. 1). The pupil is round, and the juvenile color is similar to that of the adult (Ernst and Ernst 2003, p. 92; FWC 2013, p. 1). The characteristic neck ring is indistinct or virtually absent in both juveniles and adults.

Little life-history information is available on the Key ring-necked snake, especially as it relates to microhabitat, feeding, and reproduction. Life-history characteristics are thought to be similar to the southern ring-necked snake. In general, mating of ring-necked snakes can occur in the spring or fall, delayed fertilization is possible, and eggs are laid in June or early July. Females lay 1 to 10 eggs at a time each year (1 clutch/year) in covered, moist locations (Ernst and Ernst 2003, p. 95). Juveniles are thought to hatch in August and September.

Suitable habitat appears to consist of pinelands, pine rocklands, tropical hammock, rockland hammock, limestone outcroppings, and rocky pine scrub areas (McDiarmid 1978, p. 41; Lazell 1989, p. 134; Auth and Scott 1996, p. 33; Enge et al. 2003, pp. 26-28). Most of the observations in the Florida Keys were from pine rocklands or nearby rockland hammocks. This subspecies appears to be restricted to areas near permanent freshwater that often occur as small holes in the oolitic (a sedimentary rock, usually limestone, composed of minute rounded concretions) substrate that underlies pine rocklands and rockland hammock habitat (Lazell 1989, pp. 134, 136). All
Diadophis
apparently require moist microhabitats to balance evaporative

water loss from the body (Myers 1965, p. 4; Clark 1967, pp. 492-494).

Key ring-necked snakes have been documented on seven lower Florida Keys: Key West, Big Pine Key, Little Torch Key, Middle Torch Key, No Name Key, Cudjoe Key, and Stock Island (Auth and Scott 1996, p. 33; FWC 2011, p. 3; 2013, p. 1; Mays and Enge 2016, pp. 11, 13; J. Mays 2020, pers. comm.) (see figure 1, below). A unique characteristic of the Florida Keys is the thin (<3.94 in (10 cm)) layer of sediment on the islands beneath which lies a bed of limestone, and below that a shallow layer of freshwater referred to as a freshwater lens (U.S. Geological Survey (USGS) 2019a, p. 1). Because the density of freshwater is less than the underlying saltwater, it floats to the top and into the limestone rock formations where it becomes available to the island's biota. The volume of a freshwater lens fluctuates in response to rainfall, evapotranspiration, and human use (local wells).

Systematic recent surveys have not been conducted for the Key ring-necked snake across all of the Florida Keys; therefore, the true spatial distribution of populations throughout the Florida Keys is unclear and our current understanding of the subspecies' distribution is primarily based on historical records. Consequently, this subspecies may occur on Florida Keys other than those reported.

EP14OC22.050

Figure 1.—Distribution and occurrences of the Key ring-necked snake.

Rim Rock Crowned Snake

A thorough review of the taxonomy, life history, and ecology of the rim rock crowned snake (
Tantilla oolitica
) is presented in the SSA report (version 1.0; Service 2021b, pp. 10-20). The rim rock crowned snake is in the family Colubridae, part of the black-headed, crowned, and flat-headed snake genus
Tantilla,
with 76 currently recognized species ranging from the southern United States to northern Argentina (Powell et al. 2016, pp. 395-400). The rim rock crowned snake is most closely related to the southeastern crowned snake (
T. coronata
) taxonomically, although it is located geographically closer to the Florida crowned snake (
T. relicta;
Ernst and Ernst 2003, pp. 353-355). No genetic analysis has been conducted on the rim rock crowned snake.

Rim rock crowned snakes have a black head (“cap”) that is continuous from snout to neck (“collar”), transitioning to tan or beige on its back, and a pinkish white to cream belly. There is often a pale blotch just behind the eye. Specimens from the Florida Keys may have a pale neckband that is not present in mainland specimens, separating the black cap from the black collar (Porras and Wilson 1979, pp. 218-220). Adults range 7-9 in (18-23 cm) in length. Females reach a greater length than do males, but have shorter tails (Ernst and Ernst 2003, pp. 353-355). Hatchlings range from 3-3.5 in (7.5-9.0 cm) in length.

The reproduction, longevity, and diet of the rim rock crowned snake are unknown, but if it is similar to the closely related southeastern crowned snake, it probably matures at 2 years old and may live to be at least 5 years old in the wild (Todd et al. 2008, p. 392). There may be three eggs in a clutch, and they may be able to produce two clutches annually (Ernst and Ernst 2003, pp. 353-355). There is no information as to whether eggs or juvenile rim rock crowned snakes require different habitat than adults. Predators are likely larger snake species that inhabit the same areas. It may also be preyed upon by the

slender brown scorpion (
Centruroides gracilis
), which is abundant in rockland habitat (Porras and Wilson 1979, pp. 218-220).

The rim rock crowned snake is a mostly fossorial (underground) species that inhabits shallow soil over limestone formations, and it can sometimes be found in rotten stumps and under anthropogenic surface detritus, fallen logs, and rocks (Duellman and Schwarz 1958, p. 306; Rochford et al. 2010, p. 99; Yirka et al. 2010, p. 386; FWC 2011, p. 3; Hines 2011, p. 353). These snakes are vulnerable to desiccation, so they usually occupy moist microhabitats (Powell et al. 2016, pp. 395-400). Refugia in pine rocklands and rockland hammock are provided by holes and crevices in the limestone, piles of rock rubble, pockets of organic matter accumulating in solution holes, and shallow depressions in the limestone (Enge et al. 2003, pp. 27-28). Rim rock crowned snakes likely come to the surface after rains (Porras and Wilson 1979, pp. 218-220), possibly because of flooding of its underground refugia.

The rim rock crowned snake has been historically found in the lower Florida Keys, in particular Key West and Big Pine Key; the upper Florida Keys; and the southeastern Florida peninsula within Miami-Dade County, in a variety of locations (see figure 2, below). Within this limited range, the rim rock crowned snake is found in pine rocklands and rockland hammock, which consist of a limestone substrate and outcroppings. Pine rocklands habitat is fire-maintained and dominated by pine trees and a diverse understory of grasses and forbs/herbs. In contrast, rockland hammock contains more hardwood shrubs and trees due to less fire influence. There are also occurrence records from human-altered habitats such as roadsides, vacant lots, and pastures with shrubby growth and slash pines (
Pinus elliottii
) (Duellman and Schwarz 1958, p. 306; Hines 2011, pp. 352-356).

Because of the rim rock crowned snake's cryptic and fossorial nature, a method to formally census remaining populations throughout its range has not been developed. We do not have any information on the current status of the rim rock crowned snake in these areas and based our understanding of the species' range on observational records and habitat suitability. Limited dispersal is thought to occur between rim rock crowned snake populations within the Florida Keys because there is no evidence that indicates they readily swim to other islands. Additionally, areas in Miami-Dade County where populations may remain are likely isolated from others due to physical barriers from a dense urban interface.

EP14OC22.051

Figure 2.—Distribution and occurrences of the rim rock crowned snake.

Regulatory and Analytical Framework

Regulatory Framework

Section 4 of the Act (16 U.S.C. 1533) and the implementing regulations in title 50 of the Code of Federal Regulations set forth the procedures for determining whether a species is an endangered species or a threatened species, issuing protective regulations for threatened species, and designating

critical habitat for threatened and endangered species. In 2019, jointly with the National Marine Fisheries Service, the Service issued final rules that revised the regulations in 50 CFR parts 17 and 424 regarding how we add, remove, and reclassify threatened and endangered species and the criteria for designating listed species' critical habitat (84 FR 45020 and 84 FR 44752; August 27, 2019). At the same time the Service also issued final regulations that, for species listed as threatened species after September 26, 2019, eliminated the Service's general protective regulations automatically applying to threatened species the prohibitions that section 9 of the Act applies to endangered species (collectively, the 2019 regulations).

However, on July 5, 2022, the U.S. District Court for the Northern District of California vacated the 2019 regulations (
Center for Biological Diversity
v.
Haaland,
No. 4:19-cv-05206-JST, Doc. 168 (N.D. Cal. July 5, 2022) (
CBD
v.
Haaland
)), reinstating the regulations that were in effect before the effective date of the 2019 regulations as the law governing species classification and critical habitat decisions. Accordingly, in developing the analysis contained in this proposal, we applied the pre-2019 regulations, which may be reviewed in the 2018 edition of the Code of Federal Regulations at 50 CFR 17.31, 17.71, 424.02, 424.11(d) and (e), and 424.12(a)(1) and (b)(2)). Because of the ongoing litigation regarding the court's vacatur of the 2019 regulations, and the resulting uncertainty surrounding the legal status of the regulations, we also undertook an analysis of whether the proposal would be different if we were to apply the 2019 regulations. That analysis, which we described in a separate memo in the decisional file and posted on
https://www.regulations.gov,
concluded that we would have reached the same proposal if we had applied the 2019 regulations. The differences in the 2009 Solicitor's opinion and 2019 regulations do not change our determination of what constitutes the foreseeable future for the rim rock crowned snake. Under either regulatory scheme we find that critical habitat is prudent for the two snakes. For the Key ring-necked snake, we did not identify any unoccupied areas essential for the conservation of the Key ring-necked snake, which is consistent with 2016 and 2019 regulations. For the rim rock crowned snake, by the year 2040, all suitable habitat in the lower Florida Keys and up to half of suitable habitat in the upper Florida Keys will be affected by sea level rise and saltwater intrusion. As such, we are also proposing to designate areas not currently occupied by the species, because we determined the unoccupied units are essential for the conservation of the rim rock crowned snake. It is reasonably certain that the unoccupied units will contribute to the conservation of the species by providing additional areas for rim rock crowned snake recovery actions, including population establishment, and the unoccupied units contain all of the physical or biological features that are essential to the conservation of the species and it has the abiotic and biotic features that currently or periodically contain the resources and conditions necessary to support one or more life processes of the rim rock crowned snake.

On September 21, 2022, the U.S. Circuit Court of Appeals for the Ninth Circuit stayed the district court's July 5, 2022, order vacating the 2019 regulations until a pending motion for reconsideration before the district court is resolved (
In re: Cattlemen's Ass'n,
No. 22-70194). The effect of the stay is that the 2019 regulations are currently the governing law. Because a court order requires us to submit this proposal to the
Federal Register
by September 30, 2022, it is not feasible for us to revise the proposal in response to the Ninth Circuit's decision. Instead, we hereby adopt the analysis in the separate memo that applied the 2019 regulations as our primary justification for the proposal. However, due to the continued uncertainty resulting from the ongoing litigation, we also retain the analysis in this preamble that applies the pre-2019 regulations and we conclude that, for the reasons stated in our separate memo analyzing the 2019 regulations, this proposal would have been the same if we had applied the pre-2019 regulations.

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

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

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

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

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

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

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

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

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Because the decision in
CBD
v.
Haaland
vacated our 2019 regulations with respect to our consideration of foreseeable future, we refer to a 2009 Department of the Interior Solicitor's opinion entitled “The Meaning of `Foreseeable Future' in Section 3(20) of the Endangered Species Act” (M-37021). The Solicitor's opinion

states that the foreseeable future “must be rooted in the best available data that allow predictions into the future” and extends as far as those predictions are “sufficiently reliable to provide a reasonable degree of confidence in the prediction, in light of the conservation purposes of the Act.”
Id.
at 13.

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

Analytical Framework

The SSA reports document the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the two species, including assessment of the potential threats to the species. The SSA reports do not represent our decision on whether the species should be proposed for listing as endangered or threatened species under the Act. However, they do provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies. The following is a summary of the key results and conclusions from the SSA reports, which can be found at Docket No. FWS-R4-ES-2022-0022 on
https://www.regulations.gov
and at
https://www.fws.gov/office/florida-ecological-services.

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

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

Summary of Biological Status and Threats

In this discussion, we review the biological condition of the species and their resources, and the threats that influence the species' current and future conditions, to assess the species' overall viability and the risks to that viability.

Key Ring-Necked Snake—Population and Subspecies Needs

In this discussion, we outline the resource needs of individuals and populations of the Key ring-necked snake. As part of the assessment, we first identify and describe the four most influential factors representing the individual and population needs for the subspecies: prey, refugia, water, and available suitable habitat. Due to the relative rarity of this subspecies and its secretive nature, many aspects of the life history of this taxon as well as information on population status and trends are poorly known. We rely upon ecologically and genetically similar species to draw inferences when data are lacking.

For prey, the Key ring-necked snake is assumed to be similar to other
Diadophis
species (such as the southern ring-necked snake), which prey upon small insects, snakes, lizards (anoles, geckos), slugs, amphibians (frogs, tadpoles), and earthworms (Ernst and Ernst 2003, p. 96; FWC 2013, p. 2).

Key ring-necked snakes require refugia to escape and hide from predators and to regulate body temperature. Refugia in pine rocklands and rockland hammock are likely provided by holes and crevices in the limestone, piles of rock rubble, and pockets of organic matter accumulating in solution holes and shallow depressions in the oolitic limestone (Enge et al. 2003, p. 28). Snakes are ectothermic organisms, which require an external heat source to warm their bodies in order to increase body function and productivity. Snakes can also become too hot, leading to desiccation. Therefore, a warm, moist habitat, typically subterranean or shielded from the sun, is likely a preferred refugium to escape from predators and to properly maintain homeostasis (suitable internal temperature and moisture levels).

Water is essential for Key ring-necked snake survival. This subspecies appears to be restricted to areas near permanent freshwater sources that often occur as small holes in the limestone (Lazell 1989, pp. 134, 136). The extensive network of holes, tunnels, and cavities in the limestone substrate most likely assists in creating more permanent water sources. During times of drought, these sources may become scarce and the Key ring-necked snakes may need to seek out other freshwater sources. Consequently, it is important for the Key ring-necked snake to have multiple freshwater sources in case one becomes depleted, contaminated, or unavailable. If all local water sources within a snake's home range become dry, the snake may need to expend more energy and time in search of new water sources.

The most influential need for population viability is available suitable habitat. Home range is defined as the area a snake traverses for its normal daily activities (Burt 1943, pp. 350-351; Miller 2008, p. 16). The specific acreage associated with the Key ring-necked snake's home range is unknown; however, an individual was documented traveling 154.2 feet (ft) (47 meters (m)) between coverboards (Lazell 1989, p. 134). Over 400 mark recapture measurements of ring-necked snakes in Kansas indicated a mean travel distance of 262 ft (80m) with a maximum distance of 5,577 ft (1,700 m) (Fitch 1975, p. 25). In another study, a different ring-neck snake subspecies (
Diadophis punctatus
) in northern Michigan was documented to travel between 20 ft (6 m) and 1 mile (1,609 m) (Blanchard et al. 1979, pp. 382, 385). Thus, although ring-necked snakes generally only move within a small home range, they will occasionally disperse over longer distances through suitable habitat.

In regard to population size and distribution of the Key ring-necked snake, there may be either distinct, non-interbreeding populations at each Key, or some occasional but rare level of dispersal from rafting (oceanic dispersal whereby a species travels between islands on a mass or raft of vegetation) between Keys, providing at least a small level of connectivity between individual populations. Because the Key ring-necked snake appears to be isolated to the Keys, the relatively small, archipelago of islands can each support only a small number of individuals (or separate populations).

Due to the cryptic nature of the Key ring-necked snake and limited research, there is virtually no information concerning the population structure and demographics exhibited by this subspecies. Additionally, no information exists on the abundance (number of individuals) or growth rate of these populations. Therefore, we base our assessment of the health and resiliency of these populations on the condition of its habitat as a proxy. That said, continued occurrence of populations over time at known locations suggest some ability to withstand stochastic events on the Keys, historically.

Populations of the Key ring-necked snake are supported by the existence of suitable available habitat (pine rocklands and rockland hammock) across the subspecies' range. Therefore, a strong correlation to habitat availability and Key ring-necked snake populations can be assumed but not at a level of certainty in which the presence of suitable pine rockland or rockland hammock habitat can be used as a surrogate for Key ring-necked snake presence.

Passive dispersal of individual Key ring-necked snakes among the Florida Keys may be occurring on a very limited and random basis. The level to which immigration and emigration via dispersal acts as a factor towards population resiliency and prevention against extinction for this subspecies is unknown. Many of the Florida Keys have yet to be surveyed for Key ring-necked snakes, but if occupied, they could act as “stepping stones” in the random dispersal of individual snakes by way of swimming or rafting. That said, due to the limited size of the Florida Keys, the distance between the Keys, and the fact that swimming has not been documented in Key ring-necked snakes, dispersal is not likely, and, thus, it has a limited influence on population dynamics. Overall, we lack detailed scientific information on the extent of the Key ring-necked snake's individual populations and population structure. Thus, our understanding of the factors influencing Key ring-necked snake resiliency is limited.

Because systematic recent surveys have not been conducted for the Key ring-necked snake across all of the Florida Keys, the true spatial distribution of populations throughout the Florida Keys is unclear and our current understanding of the subspecies' distribution is primarily based on historical records.

As discussed above, widely distributed populations offer better redundancy than if the populations all occur in close proximity and are vulnerable to similar threats at the same intensity or timing. Because of the Key ring-necked snake's limited geographic range, the species is exposed to threats concurrently and of similar frequency, intensity, and duration across its range. For example, the entire subspecies is vulnerable to the effects of a hurricane passing over the Florida Keys. Additionally, the extent of suitable habitat is naturally limited in the Keys. Consequently, there is little natural redundancy or “backup” for the available habitat, and natural expansion or movement of the subspecies to new areas is not probable. The minimum number of sufficiently resilient populations necessary to sustain the subspecies is unknown. Based on the presence of pine rocklands and rockland hammock habitat (total acreage 7,006 ac (2,835 ha)) in the upper Florida Keys, redundancy could be higher if discrete populations occur across the upper Florida Keys. However, the range of this subspecies appears to be restricted to the lower Florida Keys (Mays 2020, pers. comm.). Given the low likelihood of dispersal between islands, we considered islands in the lower Florida Keys (Key West, Big Pine Key, Little Torch Key, Middle Torch Key, No Name Key, Cudjoe Key, and Stock Island) as separate Key ring-necked snake populations.

As currently indicated, the Key ring-necked snake occupies a small geographic area, making it vulnerable to large-scale threats (for example, storm events/hurricanes, sea level rise) that affect the entire Florida Keys archipelago.

Because of the Key ring-necked snake's narrow geographic and ecological range, there is little variation in habitat types occupied. Also, the Key ring-necked snake does not occur across different ecosystems or have access to different systems in which to adapt. Therefore, the Key ring-necked snake has a narrow breadth of genetic and environmental diversity within and among populations.

Rim Rock Crowned Snake—Population and Species Needs

As part of the population needs assessment for the rim rock crowned snake, we identified and described the most influential factors (available prey, water, refugia, and suitable habitat) representing the individual and population needs for the species.

The diet of rim rock crowned snakes probably consists of centipedes, insects, and other small invertebrates, similar to the diet of other members of the genus
Tantilla.
Prey eaten by wild and captive
T. coronata
include tenebrionid beetle larvae, earthworms, snails, centipedes, spiders, cutworms, wireworms, and termites and their larvae (Ernst and Ernst 2003, pp. 353-355). We do not know what the prey-related requirements (abundance variety, range, etc.) are to maintain viability.

Water is essential for rim rock crowned snake survival. We have no specific information on the amount of water they require; however, similar species of
Tantilla
tend to survive in warm, moist conditions where water is intermittently available. Small amounts of water can be found in depressions and holes in the limestone substrate, which fill from rain fall or overnight dew. The extensive network of holes, tunnels, and cavities in the limestone substrate may also lead to more permanent water sources. During times of drought, these sources may become scarce, and the snake may need to seek out other fresh water sources. The rim rock crowned snake must have multiple fresh water sources in case one becomes depleted, contaminated, or unavailable. If all local water sources within a snake's home range become dry, the snake may need to expend more energy and time in search of new water sources.

Rim rock crowned snakes require refugia to escape and hide from predators and to regulate body temperature. Refugia in pine rocklands and rockland hammock are provided by holes and crevices in the limestone, piles of rock rubble, and pockets of organic matter accumulating in solution holes and shallow depressions in the limestone (Enge et al. 2003, pp. 27-28). Snakes are ectothermic organisms, which require an external heat source for homeostasis. Snakes can also become too hot, consequently leading to desiccation. Therefore, a warm, moist habitat, typically subterranean or shielded from the sun, is likely a preferred refugium to escape from

predators and to properly maintain homeostasis.

We do not know how much suitable habitat and habitat connectivity is required to maintain viability. An observation of a rim rock crowned snake was recorded (Hines 2011, pp. 352-356) at the Barnacle Historic State Park in Coconut Grove, Miami, Florida, a site that consists of only 6 ac (2 ha) of rockland hammock habitat. We do not know if pine rocklands or rockland hammocks are more suitable for the rim rock crowned snake, as they have been observed in both. Home range is defined as the area a snake traverses for its normal daily activities (Burt 1943, pp. 350-351; Miller 2008, p. 16). The rim rock crowned snake's home range size is unknown.

Rim rock crowned snake populations need abundant individuals within habitat patches of adequate area and quality to maintain survival and reproduction despite disturbance. Therefore, a strong correlation to habitat availability and rim rock crowned snake populations can be assumed, but not at a level of certainty in which the presence of suitable pine rockland or rockland hammock habitat can be used as a surrogate for rim rock crowned snake presence.

Despite these uncertainties, data indicate that the limited and patchy distribution of occupied suitable habitat is negatively affecting population resiliency across the species' range. The majority of suitable rim rock crowned snake habitat in southeastern Miami-Dade County and the Florida Keys has been developed and is highly impacted by human activities. Additionally, the Florida Keys are limited naturally in their land area.

Dispersal of individual snakes among the fragmented suitable habitat in Miami-Dade County could occur, but if it does, it is expected to be on a limited and random basis. The level to which immigration and emigration via dispersal influence population resiliency and extinction risk is unknown. Above-ground dispersal may not be as effective in a highly urbanized environment. The limited size of the suitable habitat and the distance of urban barriers between them suggest that dispersal is unlikely to currently influence the population dynamics. The extent to which rim rock crowned snakes are able to use subterranean cavities of the Miami limestone rock ridge to subvert urban barriers is unknown. Because the underlying rock ridge throughout Miami-Dade County is porous, there is potential for individuals to use it as a means of dispersal to avoid urban barriers. If used, it could allow more successful random dispersal of individual snakes than above-ground means. However, the extent of influence of dispersal remains largely unknown.

In the Florida Keys, passive dispersal of individual snakes among keys may be occurring on a very limited and random basis. The level to which immigration and emigration via dispersal acts as a factor towards population resiliency and prevention against extinction for this species is unknown. Many of the Florida Keys have yet to be searched, but if occupied, they could act as “stepping stones” in the random dispersal of individual snakes. However, the limited size of the Florida Keys and the distance between them means that dispersal is not likely; thus, it currently has a limited influence on population dynamics.

No recent surveys have been conducted for the rim rock crowned snake; therefore, the true spatial distribution of populations throughout Miami-Dade County and the Florida Keys is unclear, and our current image of the species' distribution is primarily based on historical records. Consequently, this species may very well occur on other areas in Miami-Dade County or the Florida Keys other than those reported, and the importance of the other areas (other than those with identified populations) to the overall species' resiliency is unclear. To date, no genetic analysis has been conducted on the rim rock crowned snake. Consequently, it is unknown whether or not genetically discrete populations exist in the upper or lower Florida Keys or Miami-Dade County where this species has been historically reported. No information exists on the abundance or growth rate of these populations.

Having multiple populations distributed across the landscape offers better redundancy than if the populations all occur in very close proximity and are vulnerable to stressors with the same intensity or timing. For example, the entire species is vulnerable to the effects of a hurricane passing over south Florida. Limited acreage of suitable habitat remains in Miami-Dade County and the Florida Keys; consequently, there is limited opportunity for natural expansion, and movement of the species to new areas is not probable.

Species redundancy for the rim rock crowned snake is provided by individuals being distributed across Miami-Dade County and the upper and lower Florida Keys. However, due to the lack of recent surveys conducted within Miami-Dade County and the Florida Keys, the current rim rock crowned snake's range is unknown. Despite a level of redundancy provided by the discrete populations and individuals found dispersed across Miami-Dade County and the Florida Keys, the rim rock crowned snake lacks redundancy because of its small endemic range. For some large-scale stressors (storm events and hurricanes) that affect southeastern Florida and the Florida Keys, the species is vulnerable to the timing and intensity of impacts. Overall, the rim rock crowned snake needs multiple, interconnected, healthy populations across its range.

Given the low likelihood of dispersal between islands, we considered islands in the Florida Keys as separate rim rock crowned snake populations. In the upper Keys, north Key Largo, south Key Largo, Plantation Key, Upper Matecombe Key, Lower Matecombe Key, and Marathon (Grassy and Vaca Keys) are considered separate populations. In the lower Keys, Big Pine Key and Key West are considered separate populations. Similarly, due to physical barriers (roads, structures, canals, etc.), we considered the Miami-Dade County locations as distinct populations: Arch Creek Park, Barnacle Historic State Park (BHSP), Bill Sadowski Park, Deering Estate/Ludlum Pineland Area/Chapman Field (DLC), Ned Glenn Pineland, Rockdale and Richmond Pine Rocklands Tract (Zoo Miami).

With regard to representation, the rim rock crowned snake occurs across a narrow geographic and ecological range. Consequently, there is no variation across distance or elevation as there is for other wider-ranging species. The rim rock crowned snake has not been found to occur across different ecosystems, and it is not known if it disperses farther from the limestone rock ridge in southeastern peninsular Florida.

As mentioned previously, no genetic analyses have been conducted on the rim rock crowned snake. Hence, the genetic diversity of this species is unknown, and there is little environmental diversity beyond the two habitat types where the species is found. Similarly, it is unclear if there are morphological or behavioral differences between different rim rock crowned snake populations.

Threats Discussion

We note that, by using the SSA framework to guide our analysis of the scientific information documented in the SSA reports, we have not only analyzed individual effects on the species, but we have also analyzed their potential cumulative effects. We incorporate the cumulative effects into our SSA analysis when we characterize the current and future condition of the

species. To assess the current and future condition of the species, we undertake an iterative analysis that encompasses and incorporates the threats individually and then accumulates and evaluates the effects of all the factors that may be influencing the species, including threats and conservation efforts. Because the SSA framework considers not just the presence of the factors, but to what degree they collectively influence risk to the entire species, our assessment integrates the cumulative effects of the factors and replaces a standalone cumulative effects analysis.

Following are summary evaluations of six threats analyzed in the SSAs for both the Key ring-necked snake and the rim rock crowned snake: Development (Factor A), fire suppression (Factor A), sea level rise (Factor A), saltwater intrusion (Factor A), shifts in seasonal patterns of rainfall and temperature (Factor A), and storm events (Factor A). We also evaluate existing regulatory mechanisms (Factor D) and ongoing conservation measures.

In the SSAs, we also considered four additional threats: Overutilization due to recreational, educational, and scientific use (Factor B); disease (Factor C); predation (Factor C); and invasive species (Factor E). We concluded that, as indicated by the best available scientific and commercial information, these threats are currently having little to no impact on either the Key ring-necked snake or the rim rock crowned snake and their habitat, and thus their overall effect now and into the future is expected to be minimal. Therefore, we will not present summary analyses of those threats in this document, but we will consider them in our cumulative assessment of impacts to the species. For full descriptions of all threats and how they impact the species, please see both SSA reports (Service 2021a, pp. 9-21; Service 2021b, pp. 25-40).

Key Ring-Necked Snake—Current Threats and Condition

We do not have fine-scale information to determine different levels of threats within individual populations of the Key ring-necked snake. Thus, for this subspecies, we considered threats and population resiliency on the scale of individual islands in that area.

Development

The Key ring-necked snake inhabits a variety of rockland habitat in Monroe County that has been and is still desirable for residential and commercial development (Service 1999, p. 3-174). Over half of the rockland habitat within the Florida Keys has been and continues to be altered, degraded, or destroyed for residential and commercial development (Hodges and Bradley 2006, pp. 8-9). Urban development and historical land use for agriculture have greatly reduced the extent of pine rocklands in the Florida Keys. Additionally, the quality of some pine rocklands has declined in the Keys because the remaining habitat patches are isolated and confined by surrounding urban development. Although individual snakes show some tolerance of habitat alteration, development and conversion of suitable snake habitat can impact all life stages of the Key ring-necked snake. In addition to direct impacts from loss of soils for nesting and movement and the loss of shelter and shade for adult snakes, ground cover and availability of invertebrate food sources can be reduced. Indirectly, connectivity is further decreased, hindering the finding of mates and the dispersal to new locations by juveniles.

Currently, total habitat area potentially available to Key ring-necked snakes in the lower Florida Keys consists of 1,899 ac (769 ha) of pine rocklands habitat and 3,806 ac (1,540 ha) of rockland hammock habitat (USGS 2019b, p. 4). While the hammock habitats are widespread across many islands in various sizes, pine rocklands remain on only five islands in the lower Florida Keys. One of these islands, Big Pine Key, has 1,480 ac (599 ha) (78 percent) of total pine rocklands area, while other Keys (Little Pine Key, No Name Key, Cudjoe Key, and Sugarloaf Key) contain only small areas of hardwood-invaded pine rocklands. The Florida Keys Carrying Capacity Study conducted in 2003 (Monroe County 2016, entire), concluded that development in the Florida Keys has surpassed the carrying capacity of upland habitats to maintain their ecological integrity, that any further development in the Florida Keys would exacerbate secondary and indirect impacts to remaining habitat, and that any further urbanization in areas dominated by native vegetation would exacerbate habitat loss and fragmentation.

Some habitat protections are currently in place for the Key ring-necked snake. In 2006, Monroe County implemented an HCP for Big Pine Key and No Name Key that incorporates guidelines and recommendations from the 2003 study. The primary goal of the HCP is to maintain and implement a system that directs future growth to meet goals, including to protect natural resources and to encourage a compact pattern of development. Subsequently, future development on these islands must meet the requirements of the HCP. Furthermore, to fulfill the HCP's mitigation requirement, Monroe County has been actively acquiring parcels of high-quality habitat for listed species and managing them for conservation, including pine rocklands habitat on Big Pine Key and No Name Key. Although the Key ring-necked snake is not a covered species under this HCP, we still expect the habitat protections afforded by the HCP to provide the Key ring-necked snake some protection from development.

Suitable habitat for the Key ring-necked snake is protected within preserves such as the Florida Keys National Wildlife Refuge Complex. The complex spans two Key ring-necked snake populations on No Name Key and Big Pine Key. Overall, 4,711.36 ac (1,906.62 ha) (82.6 percent) of pine rockland and rockland hammock habitats in the lower Keys are protected or under conservation (Florida Natural Areas Inventory (FNAI) 2019). The remaining suitable habitat for the Key ring-necked snake is extremely vulnerable to development. Other than these avenues to protect suitable habitat, the existing regulatory mechanisms and conservation measures do not address the impacts of development.

The effects of development have the potential to reduce individual survival of Key ring-necked snakes and, therefore, may decrease population resiliency. Resiliency may be further reduced due to loss of connectivity between populations, both as dispersal within populations as they become fragmented and dispersal between occurrences on individual islands. Similarly, because the Key ring-necked snake is endemic to only a few lower Florida Key islands, losing even a few populations to the effects of development would result in a substantial reduction in subspecies redundancy. The Monroe County HCP may prevent further development of pine rocklands, although population resiliency would continue to decline as habitats remain degraded due to impacts associated with development.

Fire Suppression

In addition to historical loss of habitat via urban development and agriculture, the quality of pine rocklands has declined due to fire suppression. Further, the quality of some pine rocklands has declined in the Keys because they are isolated and confined by surrounding urban development that restricts the use of prescribed fire, which is the principal management tool. Prescribed fire must be periodically

introduced to sustain the pine rocklands community structure. In the absence of fire, pine rocklands are invaded by many of the species found in hardwood hammocks, they lose their herbaceous flora, and they move along a successional trajectory toward hammock (Service 1999, pp. 3-173). These rockland hammocks are generally present where pine rocklands were not burned for a long period of time, leading to pine rocklands fragmentation. This fragmentation in turn increases the risk of invasion by exotic vegetation along the interface with disturbed or developed areas, further altering, degrading, or destroying suitable habitat for the Key ring-necked snake.

Although Key ring-necked snakes occur in areas where fire has been suppressed, pine rocklands habitat quality is reduced by lack of fire. Thus, fire suppression has the potential to reduce population resiliency through ongoing habitat degradation.

Climate Change

The predominant threat currently affecting the Key ring-necked snake and its habitat is the rapid and intense shifts in climate occurring as a result of increasing greenhouse gas emissions. The entire Florida Keys archipelago is being affected by increases in sea level, saltwater intrusion, increases in tide and tidal flooding, and shifts in seasonal climate pattern. In the SSA report and this proposed rule, we discuss the effects of climate change on the Key ring-necked snake in terms of sea level rise, saltwater intrusion, shifts in seasonal patterns of rainfall and temperature, and storm events (Service 2021a, pp. 23-28).

Sea level rise—
The Key ring-necked snake is vulnerable to current and predicted sea level rise across its entire range because it is located only in the Florida Keys, where the effects of increasing sea levels, higher tidal surges, increased coastal and inland flooding, and saltwater intrusion are currently being experienced (Benedict et al. 2018, pp. 9, 13, 31, 7-i; Service 2019, p. 1). The Florida Keys are among the most vulnerable areas to the effects of sea level rise due to their low mean elevation of less than 4 ft (1.2 m) (Service 2019, p. 9). Consequently, the lowest parts of the Florida Keys are highly susceptible to flooding, with parts of the islands farther upland at risk of inundation and saltwater intrusion.

Global sea level has increased by 8 to 9 in (0.20 to 0.23 m) since 1880, with the rate of increase doubling over the past 20 years (Service 2017, p. 5). From 1913 to 2018, the mean high-water line on Key West rose 0.09 in (0.23 cm) per year (National Oceanic and Atmospheric Administration (NOAA) 2019; Service 2021a, Figure 3). On Vaca Key, sea levels rose 0.14 in (0.36 cm) per year between 1971 (start of data collection) and 2018 (NOAA 2019; Service 2021a, Figure 3).

Recent analysis is now indicating an accelerated rate of sea level rise for the eastern United States above that of the global rate (Park and Sweet 2015, entire; Sweet et al. 2017, pp. 39-41, Sweet et al. 2022, pp. 20-21). The accelerated sea level rise in south Florida is being attributed to shifts in the Florida Current due to added ocean mass brought on by the melting Antarctic and Greenland ice packs and thermal expansion from the warming ocean (Park and Sweet 2015, entire; Rahmstorf et al. 2015, entire; Deconto and Pollard 2016, p. 596; Sweet et al. 2017, pp. vi, 14, 15, 18, Sweet et al. 2022, pp. 22-23). For this reason, adding approximately 15 percent to global mean sea level rise projections is recommended for southeast Florida and the Florida Keys (Park and Sweet 2015, entire; Southeast Florida Regional Climate Change Compact 2012, p. 35). The most recent intermediate sea level scenario for the Florida Keys projects a 1.1-1.2 m (3.6-3.9 ft) increase by 2100 (Sweet et al. 2022, pp. 20-21).

Based on a case study of Big Pine Key in the lower Florida Keys, saltwater intrusion due to sea level rise will begin to negatively affect the root zone of the island's upland vegetation as early as 2030, and increasing saltwater intrusion of groundwater has already been documented (USGS 2019a, pp. 1, 3). As a result, freshwater-dependent flora and fauna, which comprise much of the island's biota, will disappear. By 2040, under intermediate climate scenarios, approximately 88 percent of pine rocklands and 96 percent of rockland hammock habitat in the lower Florida Keys are expected to be impacted by sea level rise (USGS 2019a, entire). By 2040, under extreme climate scenarios, approximately 98 percent of pine rocklands and 99 percent of rockland hammock habitat in the lower Florida Keys are expected to be impacted by sea level rise (USGS 2019a, entire).

The effects of sea level rise could impact the Key ring-necked snake both through loss of individuals during flooding events, and alteration of suitable habitat, causing a loss in population resiliency. If flooding is severe enough, it could extirpate entire populations, leading to a substantial loss of redundancy.

Saltwater intrusion—Higher tidal surges, coastal and inland flooding, and saltwater intrusion due to increasing sea levels are currently being experienced in the Florida Keys. In the Florida Keys, high tide flooding events primarily affect low-lying coastal areas and exposed pine rockland and rockland hammock habitats. With worsening storms and extreme tidal events, storm surges along the Florida Keys will increase in frequency and severity over time and will impact habitats farther inland. Additionally, with continued increase in sea level rise, high tide/king tide flood frequencies are also expected to rapidly increase, with potentially severe damage to remaining rockland habitat. Pine rocklands species, particularly the dominant canopy species (slash pine), have little ability to tolerate saltwater (USGS 2019b, p. 2).

Salt from ocean water deposited during these high-water events has the potential to remain in place in and under the soil for long periods of time, which negatively impacts vegetative growth. For pine rockland and rockland hammock forests to be sustained in such an ecosystem, nutrient cycling must be extremely efficient (that is, there can be little leaching of nutrients beyond the root zone). In other instances, the effects of more powerful storm surges, rising sea levels, and saltwater intrusion of the islands' freshwater lens have contributed to the conversion and loss of pine forest habitat in the Florida Keys to more halophilic (salt-loving) vegetation such as mangroves and buttonwood (Alexander 1976, pp. 219-222; Ross et al. 1994, pp. 151-154). As discussed above in Background, a unique characteristic of the Florida Keys is the existence of a freshwater lens below each island that is critically important for humans, flora, fauna, and a variety of habitats. Consequently, pine rocklands habitat has already undergone a significant reduction in the Florida Keys due to sea level rise (Ross et al. 1994, p. 154). Currently, some of these areas are occupied by halophytic (salt-tolerant) vegetation such as mangroves and buttonwood (Alexander 1976, pp. 219-222) owing to high tide flooding as a result of rising sea level but also due to saltwater intrusion of the islands' freshwater lens. Over time, further vegetation succession will result in halophytic vegetation dominance on the remaining land and more expansive estuaries across much of the island.

Overall, saltwater intrusion from storm surge and flooding causes the loss of habitat, habitat conversion, and reduction in the capacity of freshwater storage and the freshwater resources relied upon by the Key ring-necked snake to maintain its thermoregulatory requirements. These effects will

continue to result in the loss of suitable habitat, displacement landward to less suitable habitat, and the loss of individual Key ring-necked snakes.

Shifts in seasonal patterns of rainfall and temperature—In the United States, the average temperatures have increased by 1.3 to 1.9 degrees Fahrenheit (°F) (0.77 to 1.1 degrees Celsius (°C)) since recordkeeping began in 1895 (Service 2017, p. 2). The decade from 2000 to 2009 is documented as the warmest on record (Service 2017, p. 2). Since 1991, average temperatures in south Florida have increased 1.5 °F (0.83 °C) or more (Service 2017, p. 2). Continued increases in surface air temperature are expected even if there was an immediate and aggressive reduction in human-produced greenhouse gas emissions (Intergovernmental Panel on Climate Change (IPCC) 2018, pp. 1-11).

We presume that the normal range of temperatures in which activity occurs for the Key ring-necked snake is consistent with that which it has experienced in south Florida. Any continuously higher average number of hot days out of the Key ring-necked snake's optimum range or a permanent shift in average air temperature out of this range has the potential to cause physiological stress. In more extreme cases, once an ectothermic organism is exposed to a temperature outside of its activity temperature range, it is closer to reaching a critical thermal maximum/minimum, in which locomotion becomes uncoordinated and the animal loses its ability to escape conditions that will lead to its death (Zug et al. 2001, pp. 179-188). Key ring-necked snakes may become more vulnerable to situations involving critical thermal maximum when habitat loss and fragmentation limit its ability to move or find suitable microhabitats. Additionally, ambient temperature out of the optimal range will physically influence the environment of nests, which may modify incubation periods, embryo temperatures, egg survival, and hatching times. Physiological stress can also result in a variety of risks including increased predation, reduced reproductive performance, and reduced foraging success.

Precipitation patterns are also changing. Since 1900, annual average precipitation in south Florida has increased by 5 to 10 percent (Service 2017, p. 4). Shifts in seasonal rainfall events are also currently being documented (U.S. Global Change Research Program (USGCRP) 2018, pp. 745-808). The south Florida dry season (November through April) has become wetter, the rainy season (May through October) has become drier, and current projections show that this trend will continue. This could have detrimental effects on the Key ring-necked snake's seasonal feeding, breeding, and sheltering patterns. Heavy downpours are currently increasing and have especially increased over the last 30 to 50 years. The frequency and intensity of heavy downpours in the Florida Keys have increased by 27 percent since the 1970s (Service 2017, p. 4). Increased inland flooding is predicted during heavy rain events in low-lying areas. With worsening storms, storm surges along coastlines become stronger and push farther inland. Consequently, more powerful storm surges will exacerbate the effects of the increased sea level along the Florida Keys' shorelines.

Currently, the existing regulatory mechanisms and conservation measures do not address the impacts of shifting seasonal patterns of rainfall and temperature. Although changes in seasonal weather patterns in south Florida have been documented (Service 2017, entire), direct impacts on the Key ring-necked snake's habitat have not been observed. However, with increased flooding events associated with climate change and sea level rise, the magnitude of this threat could increase into the future, decreasing population resiliency across the range of the subspecies.

Storm events—There has been a substantial increase in Atlantic hurricane activity by most measures since the early 1980s, the period during which high-quality satellite data first became available. These include measures of intensity, frequency, and duration as well as the number of strongest (Category 4 and 5) storms (Walsh et al. 2014, p. 20). Strong rainstorms, tropical storms, and hurricanes are all-natural parts of a tropical ecosystem. However, although these events are common occurrences, the vulnerability of Key ring-necked snake populations increases as the quantity and quality of their habitat is compromised. This is especially true when the frequency of storm surges increases without adequate time for habitats to recover.

Hurricane activity has been above normal since the Atlantic Multi-Decadal Oscillation (AMO) (the natural variability of the sea surface temperature in the Atlantic Ocean) went into its warm phase around 1992. While the incidence of tropical storms in southeast Florida (including the Keys) is above normal, this frequency is expected to decrease with climate change, but the intensity of the storms is expected to increase by approximately 20 percent (Service 2017, p. 7). This increased intensity results in larger tidal storm surge and greater destruction than historically documented. Ecosystem resiliency is reduced when impacts by extreme events such as floods or storms occur (Service 2017, p. 7). Saltwater intrusion from storm surge and flooding results in displacement landward to less suitable habitat and the loss of individual Key ring-necked snakes. The limestone substrate, on which snakes likely rely for cover, prey, and nesting, will become flooded more frequently, resulting in a higher frequency and longevity of displacement and stress.

Information on how strong storms impact this subspecies is lacking. However, information does exist on the impacts to habitat from hurricanes and other strong storms that have occurred in the region, providing some insight of the potential damage and loss to the Key ring-necked snake from such storms. These events likely disturb and reduce the quantity and quality of their resources (such as food and cover) and may do so significantly depending upon the severity and proximity of the storm center. This is particularly true when storm surges bring in nutrient-rich sediment that exacerbate soil accretion, salt deposition, and vegetation loss (Dingler et al. 1995, p. 296; Jackson et al. 1995, p. 321).

Additionally, saltwater surges and short-term flooding of upland habitats from strong storms and hurricanes in the Keys have the potential to kill some Key ring-necked snakes and their prey. In 2005, Hurricane Wilma (Category 3) passed just north of the Florida Keys, causing maximum storm tides 5 to 6 ft (1.5 to 1.8 m) above mean sea level in Key West and flooding approximately 60 percent of the city. On Boca Chica and Big Pine Keys, Hurricane Wilma caused a storm surge of 5 to 8 ft (1.5 to 2.4 m) (Kasper 2007, pp. 10-16). In 2017, the combined effect of storm surge and the tide from Hurricane Irma produced maximum inundation levels of 5 to 8 ft (1.5 to 2.4 m) above ground level for portions of the lower Florida Keys from Cudjoe Key eastward to Big Pine Key and Bahia Honda Key, near and to the east of where Irma's center made landfall (Cangialosi et al. 2018, pp. 8-9). A storm surge of 13 ft (4 m) would completely submerge Big Pine Key (Lopez et al. 2004, p. 284).

Currently, the existing regulatory mechanisms and conservation measures do not address the impacts of storm events. The effects of storm events have the potential to reduce individual survival, which could then lead to a reduction in the snake's resiliency and redundancy. While past storms have not resulted in complete inundation of

islands, an increase in the intensity and frequency of storms or a direct hit from a strong hurricane could cause significant reductions in subspecies numbers, further limiting the subspecies' population resiliency and making it even more vulnerable to all other threats.

Summary of Threats

Multiple threats are currently impacting the Key ring-necked snake and its habitat. Although individual populations are no longer likely to be lost to development, ongoing habitat degradation associated with urbanization of both pine rocklands and rockland hammock habitat and fire suppression of pine rocklands are continuing to reduce the availability of the features that the Key ring-necked snake needs for feeding, breeding, and sheltering, thus decreasing population resiliency. Because of the current barriers to dispersal, recolonization is unlikely after a population is extirpated.

Even minor threats that impact just a few individuals in a population need to be considered for their additive effects. For example, threats like predation and invasive species may have low impacts on their own, but combined with impacts of other threats, they are further reducing already low numbers of Key ring-necked snakes. These minor threats were considered cumulatively for their effects to the Key ring-necked snake and, while they may reduce the numbers for some individual populations, were currently found not to impose negative effects at the population level.

Additionally, various threats can originate from a similar cause but produce interdependent effects on the subspecies. For example, greenhouse gas emissions increase the rate and severity of climactic changes, which act in combination as threats on the subspecies. These include sea level rise, seasonal shifts in timing and amounts of precipitation, shifts in temperature patterns, and increased storm intensities that affect the subspecies. Sea level rise reduces available habitat. Because the average high-water line is now higher than historical levels, areas not typically flooded are now flooded on a more regular basis. The rate of sea level rise in the Florida Keys—specifically at NOAA's KYWF1-8724580 Key West ocean data buoy—had been an average rate of 0.09 inch/year (2.3 mm/year) prior to the previous decade (1990s; NOAA 2016, unpaginated). In the early 2000s, sea level rise began to accelerate exponentially and was estimated at 0.3 inch/year (7.6 mm/year) in 2016 (NOAA 2016, unpaginated).

The severity of threats may also be exacerbated by the Key ring-necked snake's limited distribution and small population size. There are no records that demonstrate that the Key ring-necked snake was ever distributed beyond the lower Florida Keys. Thus, it has, and probably has always had, low natural redundancy. Currently, it is found only on seven lower Florida Key islands. Rarity is not in itself a threat; however, small population size can exacerbate the effects of ongoing threats, making the subspecies more vulnerable to extirpation. As discussed previously, the Key ring-necked snake is a narrow endemic, meaning it has naturally low redundancy to help it buffer against stochastic and catastrophic events.

Currently, the existing regulatory mechanisms and conservation measures do not address the impacts of climate change, sea level rise, and saltwater intrusion. As mentioned above, sea level has increased exponentially since the early 2000s (NOAA 2016, unpaginated). Therefore, the effects of saltwater intrusion have likely degraded existing habitat that supports the Key ring-necked snake, leading to reductions in the features (such as freshwater) that the subspecies needs, and thus reducing population resiliency. The effects of saltwater intrusion are primarily habitat-based, but some individual snakes could also be lost. Signs of saltwater intrusion impacts are currently documented on Big Pine Key, where pine trees have been replaced by salt-tolerant mangrove. The magnitude of this threat has the potential to greatly increase in the future with the projected severity of sea level rise.

Current Condition of Populations

To characterize the current status of Key ring-necked snake populations, we assigned each stressor as low, moderate, or high impacts to the subspecies based on criteria (see table 1, below); these impacts are occurring at the individual (moderate risk) and population (high risk) levels. The risk of each threat, using the risk scoring criteria in tables 1 and 2, was applied to each population and used to assess the overall population condition (see table 3, below). More specifically, point values were summed for each threat (listed in table 1, below) to determine an overall population condition score (scoring criteria listed in table 2, below) and summarized to convey the current condition of each population of the subspecies (see table 3, below). An area with a high risk of threat as described in tables 1 and 2 will result in low population condition in table 3, and a low risk of threat will result in a high population condition. Each population received similar scores, due to limited information for the subspecies and its small endemic range. Based on the cumulative risk of threats to each population, we then estimated the current condition of each population and the likelihood of persistence of each population (Table 2). We defined populations in the SSA report and this proposed rule by the boundary of each island, as we lack information on possible population divisions within each island or about distribution between islands.

Overall, all populations of the Key ring-necked snake are in low condition and reduced from historical condition, with ongoing effects from habitat degradation, fire suppression, sea level rise, and saltwater intrusion. Though populations are currently extant on all known islands throughout the species' range, the species is only found on seven islands in a similar ecological setting. Thus, species representation and redundancy are low.

Table 1—Current Conditions Based on Risk of Threats

Threat
Low risk (1)
Moderate risk (2)
High risk (3)

Development
Development occurrence protected by land management plan
The level of development would affect suitable habitat and displace some individual snakes, but not at an extent to affect snake populations
A significant amount of suitable habitat would be lost due to development such that snake populations would be impacted.

Disease
No impacts
Some individual snakes would exhibit signs of disease, but impacts would not be widespread enough in the snake population to affect resiliency
Disease would be prevalent in populations across the range of the subspecies, decreasing population resiliency.

Fire suppression in pine rocklands
Ongoing, regular fire maintenance
The level of fire suppression would affect some suitable habitat and displace some individual snakes, but not at an extent to affect population resiliency
A significant amount of suitable habitat would be lost due to fire suppression such that snake population resiliency would be impacted.

Predation
No impacts
Some individual snakes would be predated, but impacts would not be widespread throughout snake populations
Predation would be prevalent in populations across the range of the subspecies, decreasing population resiliency.

Invasive species
No impacts
Invasive plants would not outcompete native plants to the extent that a significant amount of suitable snake habitat is altered. Nonnative fauna would outcompete some individual snakes for food, or prey on some snakes, but the effects would not be widespread in the snake population
Invasive plants would outcompete native plants altering habitat so it is no longer suitable for the snake. Nonnative fauna may outcompete snakes for food, or prey on snakes such that populations are impacted.

Sea level rise
No impacts
Individual snakes will be affected by increasing sea levels, higher tidal surges, and increased coastal and inland flooding
The severity of increasing sea levels, higher tidal surges, and increased coastal and inland flooding would impact snake populations and possibly extirpate areas.

Saltwater intrusion
No impacts
Some individual snakes will be displaced by the frequency and severity of saltwater intrusion and its impact to suitable snake habitat
The frequency and severity of saltwater intrusion and its impact to suitable snake habitat would impact snake populations, decreasing population resiliency.

Shifts in seasonal patterns of rainfall and temperature
No impacts
Individual snakes would be affected by the frequency and intensity in these seasonal patterns changes, but not to the extent that population resiliency would be affected
The frequency and intensity in these seasonal patterns changes would impact snake populations.

Storm events
No impacts
The intensity, frequency, and duration of storm events would be at a level in which the quantity and quality of individual snake needs are compromised, and some snakes would be displaced landward to less suitable habitat
The intensity, frequency, and duration of storm events would be at a significant level such that the quantity and quality of snake resources were reduced, and snake populations would be displaced.

Table 2—Risk and Overall Population Condition Scoring Criteria for Current and Future Conditions of Populations

Overall population condition
Risk of threat
Population persistence over 60 years

Probability of persistence
(%)

High (9-13 points)
1
Very Likely
91-100

Moderate (14-18 points)
2
Likely
51-90

Low (19-24 points)
3
Unlikely to likely as not
0-50

Point values for each threat (see table 1, above) were summed within an analysis area to determine the overall population condition score.

Table 3—The Risk of Threats and Their Effect on the Population Condition of the Key Ring-Necked Snake

Area
Development

Fire
suppression
of pine
rocklands

Disease
Predation
Invasive species
Sea level rise
Saltwater intrusion
Shifts in seasonal patterns of rainfall and temperature
Storms
Population condition

Big Pine Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Cudjoe Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Key West
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Little Torch Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Middle Torch Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

No Name Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Stock Island
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

The subspecies was analyzed by island. Note that the first nine columns rank the condition of threats, while the final column ranks population condition. Thus, multiple columns of high threat risk result in low population condition.

Rim Rock Crowned Snake—Current Threats and Condition

We do not have fine-scale information to determine different levels of threats within individual populations of the rim rock crowned snake. Thus, for this species, we considered threats at a larger scale in three general areas: eastern Miami-Dade County, the upper Florida Keys, and the lower Florida Keys, and on individual islands where data were available. We also considered population resiliency in isolated habitat patches in the Miami-Dade area and on individual islands in the Florida Keys. We considered North Key Largo and

Key Largo as two separate populations due to the distances between occurrences and due to several barriers to movement.

Development

The rim rock crowned snake inhabits upland rockland habitat (pine rocklands and rockland hammock) that is also desirable for residential and commercial development (Service 1999, p. 3-174). Urban development and agriculture have greatly reduced the extent of pine rocklands and rockland hammock habitat in eastern Miami-Dade County and the Florida Keys. Additionally, the quality of some pine rocklands has declined in the Keys because the remaining habitat patches are isolated and confined by surrounding urban development. Individual rim rock crowned snakes are occasionally documented in roadsides, vacant lots, trash piles, and pastures with shrubby growth and slash pines (FWC 2011, pp. 2-3; Hines 2011, pp. 352-356), but it is unknown whether these individuals are tolerating urban conditions or have been displaced. However, development and conversion of rockland habitat can impact all life stages of the rim rock crowned snake due to direct habitat loss and mortality. In addition to direct impacts from loss of soils for nesting and movement, ground cover and availability of invertebrate food sources can be reduced. Loss of habitat reduces shelter and shade for adults and decreases connectivity, thereby hindering dispersal by juveniles and finding of mates.

Extensive land clearing for human population growth, development, and agriculture in Miami-Dade and Monroe Counties has altered, degraded, or destroyed thousands of acres of suitable habitat for rim rock crowned snakes. Throughout south Florida, development and agriculture have reduced pine rocklands habitat to approximately 3 percent of historical levels. Currently, the total habitat area available in Miami-Dade County is approximately 2,275 ac (921 ha) of pine rocklands habitat and 609 ac (247 ha) of rockland hammock habitat, not including Everglades National Park (where the rim rock crowned snake has never been found), or less than 10 percent of the historical extent of this habitat. In the lower Florida Keys, the total area of pine rocklands habitat is approximately 1,899 ac (769 ha), and the total area of rockland hammock habitat is approximately 3,806 ac (1,540 ha), or less than half of the historical extent of this habitat. While the hammock habitats are widespread across many islands in various sizes, pine rocklands remain on only five islands in the lower Florida Keys and none of the upper Florida Keys. The total area covered by rockland hammock in the upper Florida Keys is 7,006 ac (2,835 ha).

Some habitat protections are currently in place for the rim rock crowned snake. Starting in 1990, Miami-Dade County's EEL program began acquiring pine rocklands and other natural areas to preserve and protect from development. Once acquired, the EEL program funds land management to maintain and protect the habitat. Since the program's inception, more than 1,500 ac (607 ha) of pine rocklands have become EEL preserves (Miami-Dade County 2019). Rim rock crowned snakes have been found at four EEL preserves.

Additionally, Monroe County implemented an HCP for Big Pine and No Name Keys starting in 2006. In 2007, a rim rock crowned snake was observed on Big Pine Key (Hines 2011, p. 353). Subsequently, development on these islands has to meet the requirements of the HCP in regard to future development. In order to fulfill the HCP's mitigation requirement, Monroe County has been actively acquiring parcels of high-quality habitat for listed species and managing them for conservation, including pine rocklands habitat on Big Pine and No Name Keys. Although the rim rock crowned snake is not a covered species under this HCP, we still expect the habitat protections afforded by the HCP to provide the rim rock crowned snake some protection from development, as the areas where the snakes occur will be avoided due to protections for species that are covered by the HCP.

Suitable habitat for the rim rock crowned snake is protected within Federal preserves such as Everglades National Park, Crocodile Lake National Wildlife Refuge, and the National Key Deer Refuge; however, the rim rock crowned snake has only been documented in the National Key Deer Wildlife Refuge and Crocodile Lake National Wildlife Refuge. Most of the other records are located on State, local government, or privately owned lands, which are all small fragments of suitable habitat. Extensive pine rocklands habitat is present in the Long Pine Key area of Everglades National Park. However, despite extensive survey efforts (Dalrymple et al. 1991, entire), no evidence of the rim rock crowned snake has been found in Everglades National Park.

Over 90 percent of suitable rockland habitat for rim rock crowned snakes has been lost due to human development in south Florida including the Florida Keys, meaning some populations (and thus redundancy) have already been lost. For example, rim rock crowned snakes were previously detected at sites in Miami near intersections of SW 27 Avenue/SW 24 Street, Old Cutler Road/Red Road, and US 1/SW 154 Ave. There are also numerous historical records detected at locations in the greater Miami metropolitan area (Kendall, Coral Gables, Ludlum, Homestead Air Base). However, no rim rock crowned snakes have been found at these locations since the 1980s. Furthermore, extensive urbanization surrounding these remaining habitats reduces survival, via rendering the species less able to withstand environmental and demographic stochasticity and disturbances (that is, reduced resiliency). Resiliency may be further reduced due to loss of connectivity between populations. Because the rim rock crowned snake is endemic to only the southeastern part of the Florida peninsula and the Florida Keys, losing even a few populations to the effects of development would result in a substantial reduction in species redundancy. However, most of the remaining habitat patches are protected, meaning few additional populations are likely to be extirpated due to development, although habitat degradation could result in continued decreases in population resiliency as the species' needs, such as prey and cover, are lost.

Fire Suppression

As discussed above under “Development,” urban development and historical conversion to agriculture has greatly reduced the extent of pine rocklands in southeastern Florida and the Florida Keys. The quality of remaining pine rocklands has declined because those areas are isolated by surrounding urban development that restricts the use of prescribed fire, which is the principal management tool for pine rocklands. Prescribed fire must be periodically introduced to sustain the pine rocklands community structure. In the absence of fire, pine rocklands are invaded by many of the species found in hardwood hammocks. They lose their herbaceous flora and move along a successional trajectory toward hammock (Service 1999, p. 3-173). These rockland hammocks are generally present where pine rocklands were not burned for a long period of time, creating more pine rocklands fragmentation. This fragmentation of pine rocklands in the South Florida and the Florida Keys increases the risk of invasion by exotic vegetation along the interface with disturbed or developed areas, further altering, degrading, or destroying

suitable habitat for the rim rock crowned snake.

Although rim rock crowned snakes can still persist in areas where fire has been suppressed, habitat quality is reduced by lack of fire. Thus, the effects of fire suppression in pine rocklands have the potential to reduce population resiliency through ongoing habitat degradation that impacts the rim rock crowned snake and its habitat.

Climate Change

The predominant threat currently affecting the rim rock crowned snake and its habitat are the rapid and intense shifts in climate occurring as a result of increasing greenhouse gas emissions. South Florida and the Florida Keys are being affected by increases in sea level, saltwater intrusion, increases in tide and tidal flooding, and shifts in seasonal climate pattern. In the SSA report and this proposed rule, we discuss the effects of climate change on the rim rock crowned snake in terms of sea level rise, saltwater intrusion, shifts in seasonal patterns of rainfall and temperature, and storm events.

Sea level rise—The rim rock crowned snake is vulnerable to current and predicted sea level rise and saltwater intrusion across its entire range because it is located only in south Florida. South Florida, including the Florida Keys, are among the most vulnerable areas to the effects of sea level rise due to their low mean elevation of less than 1.2 m (4 ft) (Service 2019, p. 9). Consequently, south Florida is highly susceptible to flooding, with lands farther upland at risk of inundation and saltwater intrusion. The effects of increasing sea levels, higher tidal surges, coastal and inland flooding, and saltwater intrusion are currently being experienced in south Florida and the Florida Keys (Benedict et al. 2018, pp. 9, 13, 31, 7-i; Service 2019, p. 1).

As discussed above in
Key Ring-necked Snake—Current Condition
under “Climate Change,”
Sea level rise,
the Florida Keys are particularly vulnerable to sea level rise, and the Florida Keys and South Florida are experiencing higher levels of sea level rise than other parts of the globe, as well as higher tidal surges, increased coastal and inland flooding, and saltwater intrusion (Benedict et al. 2018, pp. 9, 13, 31, 7-i; Service 2019, p. 1).

Consequently, pine rocklands habitat has already undergone a significant reduction in the Florida Keys due to sea level rise (Ross et al. 1994, p. 154). As mentioned previously, some of these areas are currently occupied by halophytic (salt-tolerant) vegetation such as mangroves and buttonwood (Alexander 1976, pp. 219-222) owing to high tide flooding as a result of rising sea level but also due to saltwater intrusion of the islands' freshwater lens.

The effects of sea level rise could impact the rim rock crowned snake by loss of individuals during flooding events, causing a loss in population resiliency. If flooding is severe enough, it could extirpate entire populations, particularly in the lower Florida Keys, leading to a substantial loss of redundancy of the species.

Saltwater intrusion—Higher tidal surges, coastal and inland flooding, and saltwater intrusion due to increasing sea levels are currently being experienced in south Florida and the Florida Keys. With worsening storms and extreme tidal events, storm surges along south Florida and the Keys will increase in frequency and severity over time and will impact habitats farther inland. As discussed above in
Key Ring-necked Snake—Current Condition
under “Climate Change,”
Saltwater intrusion,
this threat will result in habitat degradation and the loss of individual snakes. For the rim rock crowned snake, these effects have been primarily felt in populations in the Florida Keys, although some coastal populations in eastern Miami-Dade County may also experience some small amounts of saltwater intrusion.

Currently, the existing regulatory mechanisms and conservation measures do not address the impacts of saltwater intrusion. As mentioned above, sea level has increased exponentially since the early 2000s (NOAA 2016, unpaginated). The effects of saltwater intrusion have likely degraded existing habitat that supports the rim rock crowned snake in the Keys, leading to reductions in the features (such as freshwater) that the species needs, and thus reducing population resiliency. The effects of saltwater intrusion are primarily habitat-based, but some individual snakes could also be lost. Signs of saltwater intrusion impacts have been documented on Big Pine Key, where pine trees have been replaced by salt-tolerant mangrove. The magnitude of this threat has the potential to greatly increase with the projected future severity of sea level rise.

Shifts in seasonal patterns of rainfall and temperature—As discussed above in
Key Ring-necked Snake—Current Condition
under “Climate Change,”
Shifts in seasonal patterns of rainfall and temperature,
rising greenhouse gases are resulting in increasing temperatures and shifting precipitation patterns. Like the Key ring-necked snake, the rim rock crowned snake is a fossorial ectotherm and, therefore, dependent on gaining heat from its microhabitat or by coming into contact with the undersides of warm surfaces (for example, rocks) that are exposed to direct sunlight. As with the Key ring-necked snake, increased temperatures could result in a permanent shift in average air temperature out of rim rock crowned snake's optimal range, causing physiological stress. Physiological stress can manifest into a variety of risks including predation, reduced performance, and reduced foraging success. Altered precipitation patterns could have detrimental effects on the seasonal feeding, breeding, and sheltering patterns for the rim rock crowned snake. Increased inland flooding is predicted during heavy rain events in low-lying areas. With worsening storms, storm surges along coastlines can become stronger and push farther inland. Consequently, more powerful storm surges will exacerbate the effects of the increased sea level along south Florida and Florida Keys' shorelines and could have impacts on rockland habitat.

Currently, the existing regulatory mechanisms and conservation measures do not address the impacts of shifting seasonal patterns of rainfall and temperature. Although changes in seasonal weather patterns in south Florida have been documented (Service 2017, entire), direct impacts on the rim rock crowned snake or its habitat have not been observed. However, with increased flooding events associated with sea level rise from climate change, the magnitude of this threat could increase into the future, particularly for populations in the Florida Keys and coastal areas of Miami-Dade County, decreasing population resiliency.

Storm events—Changing patterns in hurricane activity are having similar effects to the rim rock crowned snake as to the Key ring-necked snake, as discussed above in
Key Ring-necked Snake—Current Condition
under “Climate Change,”
Storm events.
The health of the rim rock crowned snake becomes vulnerable when the quantity and quality of their resources (for example, food, cover/substrate) are compromised. This can particularly happen in the case of storm surges and with an increase in the number of incidences (for example, being impacted repeatedly without time to recover). Saltwater intrusion from storm surge and flooding results in displacement landward to less suitable habitat and the loss of individual rim rock crowned snakes. The limestone substrate, which rim rock crowned snakes likely rely on for cover, prey, and nesting, will become more frequently flooded,

creating a higher frequency and longevity of displacement and stress. Storm events likely disturb and reduce the quantity and quality of the resources for the rim rock crowned snake.

Hurricane Andrew (1992) hit southern Miami-Dade County with sustained winds in excess of 145 miles per hour (233 kilometers per hour), impacting 99 percent of pine rocklands. Within 1 year of the event, many adult trees were dead, outbreaks of
Ips
beetles (including
I. calligraphis, I. avulsus,
and
I. grandicollis
) had been reported, and two species of weevil (
Hylobius pales, Pachylobius picivorus
) had attacked juvenile trees. The outbreak has been attributed to the combination of wind damage and drought following a very dry spring, making the trees more susceptible to infestation. In a fall 1993 follow-up survey of Miami-Dade County pine rocklands, only 2 of 18 sites had living mature pines. The loss of the pines affected fire fuel production and could allow invasive species to further impact pine rocklands (Service 1999, p. 3-176).

Currently, the existing regulatory mechanisms and conservation measures do not influence or address the storm events. The effects of storm events have the potential to reduce individual survival, which could then lead to a reduction in the snake's resiliency and redundancy. While past storms have not resulted in complete inundation of islands, an increase in the intensity and frequency of storms has the potential to produce complete inundation of suitable snake habitat, and therefore possible extirpation of the species.

Summary of Threats

Multiple threats are currently impacting the rim rock crowned snake at the individual and population level and its habitat. The risk of each threat was based on the scoring criteria in tables 1 and 2, above, as applied to each population, and used to assess the overall population condition (see table 4, below).

Although individual populations are less likely to be lost to development, ongoing habitat degradation associated with urbanization and fire suppression in pine rocklands are continuing to reduce the availability of the features that the rim rock crowned snake needs for feeding, breeding, and sheltering, thus decreasing population resiliency. Additionally, all effects associated with climate change are interrelated, with shifts in the magnitude of severe storms contributing to increased flooding events that have the potential to extirpate entire populations of the rim rock crowned snake. Although a severe hurricane is unlikely to flood all populations at once, if a hurricane were to extirpate most populations, it would leave the remainder of the species significantly more vulnerable to other threats. Because of the current barriers to dispersal for populations in Miami-Dade County, recolonization is unlikely after a population is extirpated. Some populations, for example on Big Pine Key, may be able to recolonize extirpated sites because there are fewer barriers to dispersal due to less urbanization.

Even minor threats that impact just a few individuals in a population need to be considered for their additive effects. For example, threats like predation and invasive species may have low impacts on their own, but combined with impacts of other threats, they are further reducing already low numbers of rim rock crowned snakes. These minor threats were considered cumulatively for their effects to the rim rock crowned snake and, while they may reduce the numbers for some individual populations, were currently found not to impose negative effects at the population level.

Additionally, various threats can originate from a similar cause but produce a set of interdependent effects on the species. For example, greenhouse gas emissions increase the rate and severity of climactic changes, which act in combination as threats on the species. These include sea level rise, seasonal shifts in timing and amounts of precipitation, shifts in temperature patterns, and increased storm intensities that affect the species. Sea level rise further reduces available habitat. Because the average high-water line is now higher than historical levels, areas not typically flooded are now flooded on a more regular basis.

The severity of threats may also be exacerbated by the rim rock crowned snake's limited distribution and small population size. The rim rock crowned snake is not known to have occurred beyond the southeastern peninsula of Florida or the Florida Keys. Thus, it has, and probably has always had, low representation and redundancy. Currently, it is thought to exist in seven small and fragmented parcels in eastern Miami-Dade County, six islands in the upper Florida Keys, and two lower Florida Key islands. Rarity is not in itself a threat; however, small population size can exacerbate the effects of ongoing threats, making the species more vulnerable to threats.

Current Condition of Populations

As with the Key ring-necked snake, to characterize the current status of the rim rock crowned snake, we assigned each stressor as low, moderate, or high impacts to the subspecies (table 1, table 2). We summarize the current condition of rim rock crowned snake populations in table 4. Overall, the current condition of populations in the Miami-Dade area is moderate, and the condition of populations in the Florida Keys is low.

Given the species' limited distribution and limited ecological setting, representation is currently low. However, the species has moderate redundancy, as it has multiple populations distributed throughout the Miami-Dade area and the Upper and Lower Florida Keys.

Table 4—The Threat Risk and the Effect on the Current Condition of Rim Rock Crowned Snake Populations

Population
Development

Fire
suppression
in pine
rocklands

Disease
Predation
Invasive species
Sea level rise
Saltwater intrusion
Shifts in seasonal patterns of rainfall and temperature
Storms
Population condition

MIAMI-DADE COUNTY

Arch Creek
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

BHSP
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

Bill Sadowski
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

DLC
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

Ned Glenn
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

Rockdale
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

Richmond Pine Rocklands
Moderate
High
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate.

UPPER FLORIDA KEYS

North Key Largo
Moderate
High
Low
Low
Low
High
High
High
High
Low.

South Key Largo
Moderate
High
Low
Low
Low
High
High
High
High
Low.

Plantation Key
Moderate
High
Low
Low
Low
High
High
High
High
Low.

Upper Matecombe Key
Moderate
High
Low
Low
Low
High
High
High
High
Low.

Lower Matecombe Key
Moderate
High
Low
Low
Low
High
High
High
High
Low.

Marathon
Moderate
High
Low
Low
Low
High
High
High
High
Low.

LOWER FLORIDA KEYS

Big Pine Key
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Key West
Moderate
Moderate
Low
Low
Low
High
High
High
High
Low.

Note that the first nine columns rank the condition of threats, while the final column ranks population condition. Thus, multiple columns of high threat risk result in low population condition.

Future Threats and Condition

To examine the potential future condition of the snakes, four plausible future scenarios were developed. The scenarios focused on a range of conditions based on climate change scenarios and projections for land development. The range of what is likely to happen in each scenario is described based on current condition and how resiliency, representation, and redundancy would be expected to change. The levels of certainty or uncertainty are addressed in each scenario. Given that there is uncertainty as to exact future trends of many threats, these future scenarios are meant to explore the range of plausible future scenarios and examine the snakes' response across the range of these conditions.

We define viability as the ability to sustain populations over time. For this to occur, a species must have a sufficient number and distribution of healthy populations to withstand changes in its biological (predators, disease) and physical (habitat loss, climate change) environment, environmental stochasticity (flooding, storm surge), and catastrophic events (hurricanes). In considering the future scenarios for the Key ring-necked snake and the rim rock crowned snake, we analyzed expected changes in development up through 2070 based on the timeframe forecast in the urban planning documents (Zwick and Carr 2006, entire), shifts in seasonal patterns of rainfall and temperature (up through 2100), and climate change (sea level rise and saltwater intrusion) from 2030 to 2100. That said, we focused on changes that are expected in the next 20 to 60 years (
i.e.,
by 2040-2080) because virtually no habitat is forecasted to be present in the lower Florida Keys by 2080. The habitat in Miami-Dade County is forecasted to continue on the same trend up to 2100 as predicted from 2040-2080 (USGS 2019b, d, entire). We do not have any information on future trends of other threats (disease, predation, invasive species, and collection).

We chose four plausible scenarios to examine the potential impacts to Key ring-necked snake and rim rock crowned snake populations from development, fire suppression of pine rocklands habitat, climate impacts (sea level rise and saltwater intrusion), storm events, and shifts in seasonal patterns of rainfall and temperature. We determined the population condition (using criteria described above in table 1) given our future projections of threats.

In order to understand the impacts of sea level rise and associated impacts on the Key ring-necked snake and the rim rock crowned snake, we contracted a study with the USGS to measure the potential future impacts on pine rocklands and rockland hammock habitat in the range of the Key ring-necked snake and the rim rock crowned snake (USGS 2019, entire). The study calculated the impacts of root zone salinization, regional sea level rise, and high tide effects on suitable habitat in Miami-Dade County and the Florida Keys in 10-year intervals between 2030 and 2100. In this proposed rule, we present a summary of those results. Detailed descriptions of the study and its results are available in the SSA reports for the Key ring-necked snake and the rim rock crowned snake (Service 2021a, pp. 25-27; Service 2021b, pp. 43-47).

Key Ring-Necked Snake—Future Threats and Condition

Because we determined that the current condition of the Key ring-necked snake is consistent with an endangered species (see Determination of Species Status, below), we are not presenting the results of the future scenarios in this rule. For more information on the future condition, future threats, and future scenarios for the Key ring-necked snake, please see the SSA report (Service 2021a, pp. 21-33).

Rim Rock Crowned Snake—Future Threats and Condition

Development—Future Impacts

Future development is very likely to continue across the range of the rim rock crowned snake. Suitable habitat that is projected to be lost in all of these scenarios is privately owned and not currently under conservation.

Miami-Dade and Monroe Counties are not anticipated to undergo dramatic land use changes by 2070, because most land in these counties is already allocated to development, agriculture, or conservation (Carr and Zwick 2016, pp. 20-22). Of remaining pine rocklands

and rockland hammock habitat, 76 percent in eastern Miami-Dade County, 79 percent in the upper Florida Keys, and 83 percent in the lower Florida Keys are protected or conserved (FNAI 2019). However, because such limited habitat area remains, any remaining suitable unprotected habitat for the rim rock crowned snake is extremely vulnerable to development if left unprotected, and even the loss of one population (particularly in the Miami-Dade area) could have a significant effect on the species.

Of the suitable habitat for rim rock crowned snake remaining in Miami-Dade County, between 19 and 21 percent is expected to be lost to development by 2070 (Carr and Zwick 2016, pp. 20-22). Although the expected population growth in Monroe County in the Florida Keys is relatively modest, all vacant private lands not protected for conservation purposes are projected to be developed, including lands currently inaccessible for development, such as islands not attached to the Overseas Highway (U.S. 1) (Zwick and Carr 2006, pp. 14-15). This development will have the potential to further reduce the amount of suitable habitat for the rim rock crowned snake.

Fire Suppression—Future Impacts

Fire suppression has had considerable negative impacts on pine rocklands communities. The condition of some extant pine rocklands has declined and become degraded because of inadequate management or because they are isolated and confined by surrounding development that restricts th

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2022-21543. Public record. Not legal advice.