THE KEY DEER IS HEADED FOR EXTINCTION: HOW REPEALING A TRUMP-ERA FEDERAL RULE DEFINING 'HABITAT' COULD ALLOW ASSISTED MIGRATION TO SAVE SPECIES THREATENED BY CLIMATE CHANGE.

• Author: Fichtel, Kennedi

1. INTRODUCTION

   Climate change induced sea level rise is imminent. (1) In fact, the U.S. Army Corps of Engineers has predicted that "[b]y 2045, the sea level in the Florida Keys will rise 15 inches...." (2) Such a projection usually invites questions about the implications for coastal residential homeowners. However, this projection means so much more for the voiceless inhabitants of the Florida Keys. Anthropogenic climate change that leads to sea level rise of this magnitude will be responsible for permanently destroying species' habitats, and therefore impacting their ability to survive. For endangered and threatened species, this means extinction. As such, humanity has a responsibility to assist these species in their fight against obliteration.

   Climate change is a global threat, (3) and the global community must work together to combat this common enemy. This fight is especially important because vulnerable communities stand to bear the worst of what is to come from climate change. For example, sea level rise threatens to consume small island nations--placing their statehood and their territorial integrity at risk. (4) Similarly, the Key deer face a bleak future as sea level rise threatens the Florida Keys more severely than other landlocked parts of the United States.

   Isolated on islands, the Key deer cannot migrate inland as sea level rise consumes their home. Additionally, sea level rise diminishes freshwater sources crucial to the survival of the Key deer. (5) As animals, Key deer cannot lobby for their own safety. Thus, effective human stewardship is the only way to save the Key deer from extinction.

   To make matters worse, sea level rise is not the only imminent threat the Key deer face. Human activity has a long history of placing the Key deer in peril. Dating back to the 1940's and 1950's, intense hunting and habitat loss led to the near extinction of the Key deer species as a whole. (6) The installation of fences ("fencing") is also a prominent human threat to the Key deer; fencing has rendered thirty percent (30%) of Key deer habitat unusable on their home islands. (7) Between 1968 and 2002, the core areas where Key deer fawn existed decreased seventy-five percent (75%) due to urbanization. (8) Established in 1957, the National Key Deer Refuge has helped protect the dwindling population from complete extinction. (9) The Key deer's federal listing as an endangered species has provided a layer of protection; however, these efforts will be rendered useless if the tiny remainder of the Key deer's habitat is underwater by 2050. (10)

   Despite the Endangered Species Act's ("ESA") many protections, the Act does not address how to protect endangered species from habitat loss due to climate change impacts. (11) The ESA's requirement for designation of critical habitat for endangered species has the potential to offer some protection from this threat if it is used properly. (12) The ESA's section on designation of critical habitat provides that the Secretary of the U.S. Fish and Wildlife Service ("USFWS") shall, "concurrently[,] with making a determination under paragraph (1) that a species is an endangered species or a threatened species, designate any habitat of such species which is then to be considered critical habitat." (13) Critical habitat may include "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." (14)

   This protection is essential to protect species like the Key deer who face the immediate threat of losing their homes due to climate change impacts. However, a recent Supreme Court decision (15) and Trump-era rule defining "habitat" (16) have severely limited application of this section in a way that is detrimental to the Florida Key deer as climate change continues its path of destruction. Unless this Federal rule is repealed, and the Supreme Court decision is strictly limited to its narrowest possible holding, the ESA's critical habitat designation section will be far too restricted to protect the Key deer from their impending demise.

   Part II of this Article discusses the Key deer's uniquely vulnerable position and how sea level rise caused by climate change is destroying the Florida Key deer's habitat. Part III addresses the existing legal framework regarding critical habitat designations under the ESA, and how the term "critical habitat" was designated for species prior to the Trump-era federal rule and the Weyerhaeuser Co. holding. Part IV demonstrates how the pre-Weyerhaeuser Co. interpretation of Section Four of the ESA can be used to prescribe assisted migration to save species threatened by sea level rise. Furthermore, Part IV also examines how the pre-Weyerhaeuser Co. interpretation of Section Four was used to save the Western Snowy Plover from sea level rise, and how it was used to prescribe assisted migration for the Florida panther. Finally, Part V proposes that the Weyerhaeuser Co. holding must be limited and the Trump-era rule defining "habitat" must be repealed to protect the Key deer from extinction. Ideally, the Trump-era definition of "habitat" should not be replaced, but if it is replaced, a definition that considers both the goals of the ESA and the scientific definition of "habitat" is preferable.

2. THE KEY DEER'S PATH TO EXTINCTION

   The Florida Key deer, odocoileus virginianus clavium, reproduces less than any other free-ranging white-tailed deer population in North America. (17) They are endemic to the Florida Keys and are endangered under the ESA. (18) Humans have been directly threatening the species for almost 100 years through urbanization and hunting that have left the species wholly dependent on two highly urbanized islands. (19) Now the situation is only getting worse. As climate change causes sea level rise that is ravaging the low-lying coastal areas of the Florida Keys, the Key deer's habitat is being permanently destroyed. (20) Part II first outlines the Florida Key deer's uniquely vulnerable position as a species. It then highlights the dangers they face as one of the endangered species most imminently threatened by sea level rise.

   1. THE FLORIDA KEY DEER'S VULNERABLE STATUS

      The Florida Key deer is uniquely vulnerable as an endangered species whose habitat is already reduced to a fraction of what it once was. (21) The species was listed as endangered under the ESA on March 11, 1967, (22) after hunting and habitat loss led to their near extinction in the 1940s and 50s. (23) Even with federal protections, a 1990 population viability assessment predicted the 250 animals present at the time had a seventy-four percent (74%) probability of going extinct within the next sixty-seven years. (24) Despite the Key deer's endangered status, serious threats to their existence persist to this day.

      The Florida Key deer is the smallest subspecies of the white-tailed deer. (25) The principal factor affecting the distribution and movement of the Key deer is the availability of freshwater. (26) Pine rocklands and hardwood hammocks contain permanent freshwater sources, and they can now only be found on five of the twenty-six islands that make up the Florida Keys (Big Pine, Little Pine, Sugarloaf, No Name, and Cudjoe). (27) Additionally, the Key deer forage to meet nutritional requirements. (28) Many of their food sources are found in pine rock-lands and are stimulated by fire. (29) As a result, the majority of the Key deer population is relegated to relying on Big Pine Key and No Name Key for sustenance and water. (30)

      The Key deer's habitat was primarily threatened by rapid urbanization and development for many years. (31) Notably, "[b]y 2000, the footprint of homes, businesses, and roads removed approximately 232 [hectares] from usable Key deer habitat.' (32) This urbanization and development continues to severely threaten upland freshwater sources, (33) only compounding other imminent threats like sea level rise. For example, fencing creates habitat fragmentation that can prevent the Key deer from reaching water sources directly, causing them to have to cross major roads, which may lead to vehicle collision deaths. (34) Worse yet, uninterrupted Key deer habitat is in short supply because fencing covers thirty percent (30%) of developed areas on the Key deer's home islands. (35) As of 2020, there are only about 1,145 acres (463 hectares) of usable Key deer habitat left on Big Pine and No Name Keys. (36) While urbanization and fencing remain a major concern, those challenges pale in comparison to the imminent threat of climate change.

   2. SEA LEVEL RISE WILL PUSH THE FLORIDA KEY DEER TO EXTINCTION

      Climate change has created a host of new threats, including aggressive sea level rise, which will push the Key deer to extinction. (37) Global sea levels rose approximately seven inches in the Twentieth Century due to thermal expansion and melting land ice, with the rate now increasing. (38) Counties in South Florida have recommended that infrastructure projects with an expected life of more than fifty years account for nearly three feet of sea level rise by 2060, and nearly seven feet of sea level rise by 2100. (39) The dangers of sea level rise in the Florida Keys are particularly acute: "[w]ith a mere one foot of sea-level rise, four hospitals, sixty-five percent (65%) of the schools and seventy-one percent (71%) of the emergency shelters in the Florida Keys are vulnerable...." (40)

      About eighty-six percent (86%) of the islands the Key deer occupy are less than three feet above sea level, (41) which underscores how serious sea level rise is for the Key deer. The Center for Biological Diversity documented the dangers of sea level rise caused by climate change in a report, titled "How Rising Seas Threaten 233 Endangered Species" ('The Report"). (42) The Report compiles data from the USFWS, the National Marine Fisheries Service...