January 01, 2018

Crocodile Smiles: How Listed Species Cope in an Age of Urbanization

Kelly Cox and Brett Brumund

As cities increase in population and geographic area, their impact on the environment inevitably increases. Most obvious is the destruction or modification of the natural environment in a city’s expanded footprint. Typically, such impact is negative because it displaces native species of plants and animals and can disrupt natural processes. A less obvious, but as readily harmful, impact directly tied to expanding cities is the need to increase services such as electricity generation or sewage infrastructure to meet a growing population’s needs. Providing such services takes up space and can displace native plants and animals and add water, air, heat, and noise pollution to the environment. Congress has recognized the importance of protecting the most vulnerable impacted species and environments in the Endangered Species Act (ESA). However, the ESA’s strong protections for species threatened with extinction can come into direct conflict with both cities and those that provide the necessary services for continued growth. This is true particularly when listed species take up residence on private property, a situation that occurs with increasing frequency in urban environments.

City expansion and listed species are often at odds with one another. A 2005 study by the National Wildlife Federation, Smart Growth America, and NatureServe found that there are more than 4,000 imperiled species living in the continental United States. See Reid Ewing and John Kostyack et al., Endangered by Sprawl: How Runaway Development Threatens America’s Wildlife, National Wildlife Federation, Smart Growth America, available at www.nwf.org/~/media/PDFs/Wildlife/EndangeredbySprawl.pdf. Of those species, 60 percent live within metropolitan areas, and half of those live in major metropolitan areas with more than one million people and the fastest growth rates in the country. Habitat loss due to urbanization and development proceeds seemingly unabated, wreaking havoc for ecosystems and the species that thrive in these places.

This is clear particularly in the landmark environmental law case National Association of Home Builders v. Babbitt, 130 F.3d 1041 (D.C. Cir. 1997). This case involved the endangered Delhi Sands flower-loving fly, a small species of fly that lives only in the “Delhi series” soils of southwestern San Bernardino County and northwestern Riverside County in California. San Bernardino County planned to redesign an intersection to improve emergency access to a new hospital, which would have impacted 70 to 80 percent of a corridor connecting the fly’s critical habitat and, in the view of the U.S. Fish and Wildlife Service (FWS), likely resulted in an ESA taking. The county brought a Commerce Clause claim, arguing that Congress improperly exercised its authority in ESA section 9 by regulating a species that lives only in one state. The federal government, and the flower-loving fly, ultimately prevailed, with the court holding that single-state endangered species substantially affected interstate commerce and could be regulated by Congress. Id. at 1057 (applying United States v. Lopez, 514 U.S. 549 (1995)).

Such conflicts between cities and listed species are common as urbanization increases. This is a trend we have seen worldwide with plants and wildlife populations declining as city sizes and services grow. For example, firefly populations have declined globally due to increased light pollution from nearby cities, and, according to the group Whale and Dolphin Conservation, China’s Yangtze River Baiji dolphin is now considered to be functionally extinct because of habitat destruction, pollution, and industrial development associated with urbanization. See World Dolphin Conservation, The Baiji—The First Dolphin to Be Declared Extinct in Modern Times, available at http://us.whales.org/case-study/baiji-first-dolphin-to-be-declared-extinct-in-modern-times. This species is largely considered to be the first cetacean species that has gone extinct as a direct result of human activity. Similarly, the World Wildlife Federation has found that the Mekong catfish has declined dramatically, by 90 percent or more, due to major infrastructure projects like dams built to support sprawling population centers. World Wildlife Federation, River of Giants: Giant Fish of the Mekong, May 2010, available at wwf.panda.org/about_our_earth/species/profiles/fish_marine/giant_catfish.

Back home in Florida, we see these types of declines all too regularly. Florida manatee decline has been closely correlated with coastal development and industrial activities that cause water pollution. They are impacted by boat strikes associated with more boaters in the water and suffer from fishing line entanglement. Similarly, the Florida Bonneted Bat has experienced a precipitous decline due to habitat loss, modification, and degradation as a direct result of human population growth and associated development. Of course, the Florida panther also has experienced dramatic population declines because of the growing South Florida human population. Roads have been built that directly bisect critical panther habitat—fragmenting the habitat and making it both difficult and dangerous for panthers to access food, water, and shelter.

Another Florida species that has been the subject of adverse impacts is the American crocodile (Crocodylus acutus), a coastal crocodilian seen primarily in southern mainland Florida and the northern Florida Keys. South Florida is the northernmost extreme of the American crocodile’s range. The American crocodile also may be found in Cuba, Jamaica, Hispaniola, southern Mexico, Central America, Ecuador, and Venezuela. The historic distribution of the American crocodile in Florida extended along both the east and west coasts of the state to Vero Beach and Tampa respectively. The last time that a crocodile was spotted as far north as Vero Beach was in 1974. See James Kushlan and Frank Mazzotti, Historical and Present Distribution of the American Crocodile in Florida, 23 J. of Herpetol. 1–7 (1989). Along the west coast, crocodiles were observed periodically throughout the 1980s in Naples, Sanibel, and Tampa. However, in recent years, crocodile distribution generally has been limited to Lee, Collier, Broward, Monroe, and Miami-Dade Counties. The nesting range of crocodiles is more restricted than the dispersion of individuals.

In Florida, the primary threat to these animals has been habitat loss, due to development supporting a rapidly growing human population and urbanization along coastal areas of Palm Beach, Broward, Miami-Dade, and Monroe Counties. See Frank Mazzotti et al., American Crocodile in Florida: Recommendations for an Endangered Species Recovery and Ecosystem Restoration, 41 J. of Herpetol. 1, 122–132 (2007). When the FWS listed the crocodile as endangered in 1975, there were only an estimated 10 to 20 breeding females in Florida. See 40 Fed. Reg. 17,590 (Apr. 21, 1975). Since being listed, American crocodile populations have returned, resulting in the crocodile’s downlisting to threatened in 2007. This achievement can be attributed to sound management and conservation, as well as help from an unlikely place—a nuclear power plant that turned out to be haven for nesting crocodiles. Putting all your crocodile eggs in one basket, however, may not yield the best long-term results, for while the American crocodile population is much more stable now, it remains vulnerable, with around 2,000 individuals, excluding hatchlings, alive as of the 2007 downlisting. See 72 Fed. Reg. 13,027, 13,031 (Mar. 20, 2007).

Species Profile

The American crocodile typically is found in freshwater or brackish coastal habitats, including rivers, coastal lagoons, and mangrove swamps. Although principally a coastal species, the American crocodile is ecologically adaptable and is known to extend its distribution inland, especially along courses of larger rivers, but also into landlocked water bodies, including areas with ranging salinities. American crocodiles inhabit disturbed or man-made habitats, a common observation throughout their range in southern Florida. Most notably, they use canal berms for nesting. There are three primary nesting locations for crocodiles in Florida: Crocodile Lake National Wildlife Refuge, Everglades National Park, and Florida Power & Light (FPL) Company’s Turkey Point Nuclear Generating Station. Most crocodiles at the Turkey Point site are found in the cooling canal system (CCS) or in ponds on the FPL property. The elevated canal banks within the CCS provide nearly ideal nesting conditions for the crocodiles. See Susan Salisbury, Researchers Wary as Crocodile Nests, Hatchlings Drop at FPL Nuke Plant, Palm Beach Post, Oct. 3, 2015.

Crocodile survival and nesting success have been linked to regional hydrographic conditions, including rainfall, water level, and salinity. Many marine species can tolerate hypersaline conditions; however, for the American crocodile, frequency and duration of hypersaline conditions is ecologically limiting. Such conditions are energetically expensive for the crocodiles and result in a reduced capacity for biological processes such as growth and mating. Hatchling crocodiles are especially vulnerable to biotic and abiotic stressors because of their small size. See Frank Mazzotti et al., “American Crocodile in Florida: Recommendations for an Endangered Species Recovery and Ecosystem Restoration,” 41 J. of Herpetol. 1, 122–132 (2007). Hatchlings require benign environmental conditions to grow and survive. Higher mortality rates for hatchling crocodiles have been associated with areas that pose a greater risk of hypersaline events. Crocodiles are also sensitive to temperature because nesting temperature determines crocodile sex. Males are only produced when eggs are kept within a narrow temperature band. Warmer air and water temperatures heat the sand in which the eggs are incubating. If temperatures get too hot, the ratio of males to females can be upset, or eggs will not hatch at all.

Hatchling survival has also been shown to decrease with increased distance to suitable nursery habitat. Nursery habitat for the American crocodile includes areas that are protected from wind and wave action and have low to moderate salinity, water, abundant food, and shelter. At Turkey Point, the distance from nest to nursery ranges from meters to hundreds of meters. See Mazzotti et al. 2007, supra. Scientists have hypothesized that saline water and long-distance dispersal limit hatchling growth and survival at Turkey Point. Id. Further, scientists hypothesize that low survival of crocodiles may be a result of a greater proportion of inaccessible habitat. Id.

Turkey Point Population

Crocodiles were first observed at Turkey Point in 1976 soon after the CCS began operating. Nesting was discovered in 1978 for the first time when hatchling crocodiles were observed and captured in the cooling canals. See Laura Brandt et al., Status of the American Crocodile (Crocodylus acutus) at a Power Plant Site in Florida, USA, 3 Herpetological Nat. Hist. 29–36 (1995). More than 330 nests were reported at Turkey Point between 1978 and 2008. See Frank Mazzotti et al., Alligators and Crocodiles as Indicators for Restoration of Everglades Ecosystems, 9 Ecol. Indicators 6, 137-S149 (2009). Turkey Point had the highest rate of nest success (proportion of all nests laid that produce at least one hatchling) between 1978 and 2008 at 98 percent and the lowest annual variation in success.

In 2014, FPL reported an overall decrease in the number of crocodiles in the CCS. FPL attributed this decrease to removal and relocation of all known hatchlings from the CCS and to extreme temperature and salinities in the system. The total number of nests decreased from between 20 and 25 nests over the previous five years to about five nests. See Jenny Staletovich, Turkey Point Canals May Be Too Salty for Nesting Crocs, Miami Herald, Oct. 29, 2015. Historically, the Turkey Point CCS produced a third of crocodile nests statewide and served as one of only a handful of nesting grounds for crocodiles in Florida. See Kushlan and Mazzotti 1989, supra. Notably, the change experienced at Turkey Point was on an order of magnitude experienced at no other nesting location monitored in the state.

As a privately owned company, FPL is obligated not to “take” any listed species, including crocodiles, unless the FWS issues FPL an incidental take permit. Section 3(19) of the ESA defines “take” as to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or attempt to engage in any such conduct. These terms are further defined by regulation and case law but generally apply to direct actions on a species that kill or injure an individual, significantly modify or degrade critical habitat, or significantly impair or disrupt normal behavioral patterns. See 50 C.F.R. § 17.3; see also Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687 (U.S. 1995). While the ESA’s prohibitions are strong, regulated entities do have some leeway when engaging in some activities that may result in a taking by way of an incidental take permit. Section 10(a)(1)(B) of the ESA allows FWS to permit a taking of a listed species by both public and private actors as long as the taking is incidental to, and not the purpose of, an otherwise lawful activity and the taking will not jeopardize the species’ continued existence.

Habitat conservation plans (HCPs) are essential to the incidental take permit for nonfederal actors, such as FPL. An HCP requires the private party requesting the permit to show they will minimize and mitigate the impacts of an incidental taking as much as practicable. The HCPs must include an assessment of the impacts that are likely to take a listed species; the measures the permit applicant will take to monitor, minimize, and mitigate for such impacts; the funding available to implement such measures; the procedures to deal with unforeseen circumstances; and any alternative actions available that would not take a listed species. If unforeseen circumstances do arise, ESA section 10(a)(1)(B) protects private landowners from being required to commit resources in addition to those specified in the HCP.

What happens if a private party manages its property in a way that attracts listed species? If the private actor does not anticipate taking a listed species and does not seek an incidental take permit, then it is business as usual—the property owner is still prohibited from taking the listed species. Additionally, under Sweet Home, the property owner would be prohibited from modifying the listed species’ habitat in a way that causes actual harm to the species or alters its essential behavioral patterns. However, if a listed species comes into conflict with the property owner’s use of private property and inadvertent takings may occur, an incidental take permit and accompanying HCP likely would be required. The private landowner would, therefore, be held to the terms in the HCP as approved by FWS.

Regardless of whether FPL intended to or not, the Turkey Point facility has attracted a listed species by creating an ideal nesting habitat. Under the ESA, FPL has obligation to manage its property in a way that will not adversely impact listed species. Further, FPL has a legal responsibility, pursuant to their incidental take permit and HCP, to avoid adverse habitat modification, including degradation of the CCS. This obligation gives FPL few options to avoid further impacts to the crocodiles on-site at Turkey Point, one of which would be to decommission the CCS and reclaim it as crocodile habitat.

Power Plant Proximity

To meet the needs of a growing city’s inhabitants, the city and actors like public utilities must expand the services they provide, like electricity generation. Electricity generation can have environmental effects depending on the electricity’s source, the characteristics of the surrounding area, and state and local regulations. Generators can send electricity over great distances using high-voltage transmission lines, but often it is best to site a power plant close to the area in which the electricity is needed to reduce the cost of building, maintaining, or upgrading transmission lines. Generators must consider factors such as access to resources like fuel and water, local zoning laws and regulations, electricity demand, and potential impacts to the nearby population and environment when deciding where to build new power plants.

Urban development and the natural environment both limit available electricity generation space. South Florida is a prime example of this—just over six million people live on a relatively narrow strip of land between the Atlantic Ocean and the Everglades. Urban and suburban areas extend uninterrupted from northern Palm Beach County down to Homestead and Florida City in southern Miami-Dade County. The southern end of the region is sandwiched between two national parks—Everglades and Biscayne—both of which are home to the only U.S. population of the threatened American crocodile. This means that energy generation facilities are relegated to the fringes of the developed area on either the Atlantic Coast or near each county’s western and southern urban development boundaries, areas that are more likely to house vulnerable species and sensitive environments.

Turkey Point is one such facility. Turkey Point is situated conspicuously in southern Miami-Dade County. According to 2010 U.S. census data, about 162,000 people live within 10 miles of the facility and 3.5 million people live within 50 miles. The region’s population center, downtown Miami, lies only 24 miles north of the Turkey Point facility, and the cities of Homestead and Florida City lie about eight miles west of Turkey Point. In addition, the Biscayne Aquifer, a surficial aquifer that provides drinking water for South Florida and the Florida Keys, lies below the entire region. The aquifer’s shallow depth makes it particularly susceptible to contaminants leaking from canals, and heavy use makes it susceptible to drought.

The region also boasts two national parks that protect unique and sensitive environments—Everglades National Park, which protects much of the southern Everglades, and Biscayne National Park, which protects Biscayne Bay, barrier islands, and offshore coral reefs. Turkey Point sits about nine miles from Everglades National Park’s eastern border and mere yards from Biscayne’s western border on the shores of the Bay. In fact, Turkey Point first began operating in 1968, the same year that Biscayne Bay was declared a National Monument. Just south of Turkey Point are ecologically important mangrove forests and the southern Everglades. This area includes critical habitat for several ESA listed species, including manatees, sea turtles, smalltooth sawfish, and the threatened American crocodile.

Current Problem

FPL is one of the largest energy providers in Florida—serving over 4.6 million customers across much of Florida’s east coast (including South Florida) and a portion of Florida’s southwest coast. In 2007, faced with increasing electricity demand and regional population growth, FPL began the process of an extended power uprate for the nuclear reactors at their Turkey Point facility. Through the uprate, FPL could generate an additional 525 megawatts of electricity—a nearly 15 percent increase in output. The additional electricity production increases the amount of waste heat, however, which in Turkey Point’s case is released into the cooling canals enjoyed by the American crocodile.

In 2014, one year after the uprating process was completed, University of Miami engineers found that the water temperature in the canals increased so much that the facility was at risk of exceeding the NRC’s 100° Fahrenheit (F) limit for cooling water at nuclear facilities and temporarily shutting down. FPL applied to the NRC for an emergency operating temperature increase that allowed the reactors to continue operating until cooling water temperatures reach 104°F. See U.S. Nuclear Regulatory Commission, Biological Assessment on the American Crocodile (Crocodylus acutus): Turkey Point Nuclear Generating Unit Nos. 3 and 4, Proposed License Amendment to Increase the Ultimate Heat Sink Temperature Limit (July 2014). That year, the plants were forced to shut down twice due to overheating. Higher temperatures also likely resulted in a massive algal bloom that engulfed the CCS caused by a nitrogen-fixing cyanobacteria that thrives in warm, hypersaline water. The South Florida Water Management District has suggested that increased algae concentrations will result in more solar energy absorption by the canals and reduced thermal energy dissipation and raised yet another challenge to the health of the CCS ecosystem.

Increased temperatures in the canals also impact the canal water’s salinity. As built, the canals’ salinity was expected to steadily increase over time by 5 percent per decade. Following the uprate, the higher water temperatures caused the evaporation rate to increase. As water temperature increases it evaporates more readily, leaving the remaining water saltier and denser. During the summer of 2014, salinity in the canals increased from about 60 parts per thousand (ppt) to about 90 ppt—essentially brine. See Staletovich, supra. For reference, salinity in the immediately adjacent Biscayne Bay averages around 33 ppt.

Cooling Canal Decline and Crocodile Impacts

With increasing development and habitat destruction in South Florida, displaced species have few places left to go. The American crocodile is a prime example of this phenomenon; the region’s beaches and mangrove forests have become housing developments, marinas, and resorts. In its revised 1999 American crocodile species recovery plan, FWS noted that urbanization outside of the crocodile’s historic range will prevent displaced crocodiles from finding new areas to colonize.

Turkey Point’s cooling canal system hosts the highest concentration of the crocodiles in South Florida. See Frank Mazzotti & Michael Cherkiss, “Status and Conservation of the American Crocodile in Florida: Recovering an Endangered Species while Restoring an Endangered Ecosystem,” University of Florida Report (2003). As discussed, these canals are ideal nesting habitat for the American crocodile. While scientists are unable to say conclusively that the hypersaline conditions of the canal system are the singular cause of nest decline, the evidence is correlative. The rapid rise in salinity correlates to both the decline in nests and hatchling survivorship.

The weather-dependent nature of the cooling system at Turkey Point brings into question the long-term viability of one of Florida’s American crocodile population’s largest nesting sites. Rising global temperatures and a changing climate could lead to a hotter, saltier CCS, forcing crocodiles to seek nesting habitat in their historic range farther north in coastal Miami or south in the Florida Keys. This would put the crocodiles in direct conflict with humans and urbanized areas. Already, as the crocodile population has increased since ESA listing, crocodiles have been found in swimming pools and residential lakes. In 2014, the first documented crocodile bites in Florida occurred in the city of Coral Gables’ canals. See Monique Madan, Crocodile Attacks Swimmer in Coral Gables Canal, Miami Herald, Aug. 25, 2014. Habitat conflicts will only become more prevalent as the CCS deteriorates and crocodiles seek viable habitat elsewhere.

Balancing Species’ Interests with the Human Population

As urban population centers grow across the United States, it is becoming increasingly necessary to balance the interests of species, particularly listed species, with those of the human population. Increased urbanization results in habitat fragmentation, biodiversity loss, potential decreases in ambient water and air quality, and many other impacts. The protections the ESA gives to listed species are only effective with sound management and participation by all stakeholders. This includes private property owners when listed species take up residence on their property. Proper management and consideration is necessary to ensure listed species’ survival in urban environments. Cities can work together with wildlife managers and regulatory agencies to ensure that these species are given consideration as the city grows. For example, cities can implement integrative ecosystem-based management plans that consider sustainable development with the ecosystem in mind. Cities also can ensure the existence of wildlife corridors by promoting connected public lands. Finally, cities can engage in restoration efforts to convert old industrial sites to now usable and functioning ecosystems.

In the case of the Turkey Point crocodiles, it is high time that FPL considers decommissioning the CCS for the benefit of both the ecosystem and the crocodiles’ and region’s health. In 2016, the Florida DEP ordered FPL to both bring CCS salinity down to match Biscayne Bay and improve the CCS’s thermal efficiency. See Consent Order, Florida Dept. Environmental Protection v. Florida Power and Light Co., (No. 16-0241, Florida Dept. Env. Prot., June 20, 2016). DEP’s primary objective was to eliminate the CCS’s discharge of hypersaline water into both the Biscayne Aquifer and Biscayne Bay via groundwater within 10 years. Freshening the canals will greatly help the survival of juvenile crocodiles and is a move toward restoring an important piece of crocodile habitat. However, the freshening process requires 15 million gallons of water daily from groundwater sources—an additional withdrawal from the region’s already stressed water supplies. Both the crocodiles and the canals need a better and longer-term solution. The CCS is an outdated system mired with complications. This system, and the units that connect to it, should be retired in lieu of more environmentally friendly options. Further, because scientists already know that this system of canals and berms provides great habitat for a listed species, FPL should restore the CCS, which would greatly benefit both the public and the crocodiles. By restoring the canal system, removing water quality contaminants, eliminating surficial algae, and ensuring the crocodile’s access to the water, FPL can continue to allow the American Crocodile population to rebound in South Florida.

Kelly Cox and Brett Brumund

Ms. Cox is the staff attorney and program director at Miami Waterkeeper. She may be reached at kelly@miamiwaterkeeper.org. Mr. Brumund is a third-year law student at the University of Miami School of Law. He may be reached at b.brumund@umiami.edu.