Kevin Enge

Florida Fish and Wildlife Conservation Commission | ffwcc · Wildlife Research

Effective management of a species requires that resource managers know critical aspects of its ecology, including information on home range and habitat use. We conducted the first telemetry study on the Suwannee alligator snapping turtle (Macrochelys suwanniensis), and we examined movements at an upper river (UR) site and a lower river (LR) site in...

Geological processes influence water chemistry and biological productivity along the Suwannee River and divide the mainstem of the river into 6 distinct ecological reaches (ERs) in Florida. Because of these distinctions, we hypothesized that the Macrochelys suwanniensis (Suwannee Alligator Snapping Turtle) population varies among ERs. During 2011–2...

Combat has been described in captive but not in wild Macrochelys temminckii (Alligator Snapping Turtle). Combat may be seldom observed in the wild because of the habitats used by these highly aquatic, cryptic turtles. We report 1 observation of fighting in M. temminckii and 3 observations of fighting in M. suwanniensis (Suwannee Alligator Snapping...

The published literature does not provide a consensus regarding maximum body sizes of North America's largest wild freshwater turtles (genus Macrochelys). The largest known wild M. suwanniensis (Suwannee Alligator Snapping Turtle) currently exists as a curated specimen measuring 713 mm straight-midline carapace length, 801 mm maximum carapace lengt...

With the conservation status of Macrochelys (alligator snapping turtles) being examined at the national level, our objective was to compile categorical data on threats from anthropogenic interactions. We included information from (1) author-collected anecdotes on human–turtle interactions and (2) radiographs to assess the prevalence of ingested fis...

Alligator snapping turtles (genus Macrochelys) are the largest freshwater turtles in North America. Despite strong interest in their conservation, we still lack a comprehensive understanding of their natural history, including behaviors associated with terrestrial activity. We reviewed the literature and solicited unpublished observations of terres...

With the conservation status of Macrochelys (alligator snapping turtles) being examined at the national level, our objective was to compile categorical data on threats from anthropogenic interactions. We included information from (1) author-collected anecdotes on human-turtle interactions and (2) radiographs to assess the prevalence of ingested fis...

We determined the occurrence in Florida, USA, of the Gopher Frog (Rana capito) primarily by conducting dipnet surveys of 1,330 potential breeding ponds on 113 conservation lands in 44 counties and 23 ponds on private lands in 12 counties. We compared recent and historical records to determine distributional trends, and we developed a Maxent Potenti...

For approximately four decades, scientists have known of the existence of several undescribed species of Siren in the southeastern United States Coastal Plain. One of these species, S. reticulata, was recently described, but a small, seepage-dwelling species has remained undescribed until now. To resolve outstanding questions concerning the phyloge...

An inherent challenge in managing rare or cryptic species is data deficiency. For this reason, ancillary data is a potentially valuable resource for generating key population estimates for priority species. We compiled ancillary commensal data collected between 1982 and 2020 during surveys of gopher tortoise ( Gopherus polyphemus ) burrows to estim...

Delineating genetically distinct population segments of threatened species and quantifying population connectivity are important steps in developing effective conservation and management strategies aimed at preventing extinction. The gopher frog (Rana capito) is a xeric-adapted, pond-breeding species endemic to the Gulf and Atlantic coastal plains...

Populations of amphibians that breed in isolated, ephemeral wetlands may be particularly sensitive to breeding and recruitment rates, which can be influenced by dynamic and difficult-to-predict extrinsic factors. The gopher frog Rana capito is a declining species currently proposed for listing under the U.S. Endangered Species Act, as well as one o...

Freshwater megafauna populations, which are declining worldwide, are well known but often overlooked and understudied compared with marine and terrestrial megafauna. One species of freshwater megafauna is the Suwannee alligator snapping turtle (Macrochelys suwanniensis), which is endemic to the Suwannee River drainage in Georgia and Florida. Severa...

Eastern Indigo snakes in the Florida Keys

The Suwannee alligator snapping turtle (Macrochelys suwanniensis) was first described in 2014. The species is thought to occur in blackwater and spring-fed streams of sufficient size throughout the Suwannee River drainage, but we have limited detailed information regarding its range. To clarify the distribution of M. suwanniensis, we compiled 111 m...

Management decisions for species are often based on estimates of abundance, which can be difficult to obtain for species that are a challenge to survey, as are some reptiles. Information on abundance and population status are lacking for the diamondback terrapin (Malaclemys terrapin), a coastal species that inhabits brackish waters and plays an imp...

The gopher frog Lithobates capito is one of the most terrestrial frogs in the southeastern United States and often inhabits gopher tortoise burrows Gopherus polyphemus outside of the breeding season. Gopher frog populations have declined, and the species is under review for listing as threatened or endangered under the U.S. Endangered Species Act....

We conducted roadside call surveys at 111 historical Hyla andersonii (Pine Barrens Treefrog) sites in 2013-2016. We detected the species at 49 sites (44%), which is consistent with surveys conducted in the early 1980s. We detected the species throughout its historical range except Holmes County, which only has 4 historical sites. We also identified...

The US Endangered Species Act of 1973 (ESA) affords many potential benefits to species threatened with extinction. However, most at-risk amphibians—one of the most imperiled vertebrate groups—remain unlisted under the provisions of the ESA, and many impediments to recovery exist for those species that have been listed. Of the 35 US amphibian specie...

Section 6 funds were used to conduct surveys to determine the status and distribution of three rare and imperiled pond-breeding amphibians: striped newt (Notophthalmus perstriatus), frosted flatwoods salamander (Ambystoma cingulatum), and reticulated flatwoods salamander (A.bishopi). This report summarizes the results of surveys for these species f...

More nonindigenous species occur in Florida, USA, than any other region worldwide and may threaten many of Florida's natural resources. The frequency of new reports mandates the need for regular updates. Herein, we use photographic and specimen vouchers in addition to literature records to provide updated information on verified nonindigenous amphi...

Objectives of this project were to determine population trends, current occurrence on public lands, and possible reasons for extirpation or decline of populations of 5 amphibian Species of Greatest Conservation Need: striped newt (Notophthalmus perstriatus), eastern tiger salamander (Ambystoma tigrinum), frosted flatwoods salamander (A. cingulatum)...

Two new species of alligator snapping turtles (Macrochelys apalachicolae and M. suwanniensis) have been described, and information on their distribution is important in order to develop effective conservation strategies. Seven small coastal rivers between eastern Wakulla County and Dixie County, Florida, apparently separate these two new species. D...

The Alligator Snapping Turtle, Macrochelys temminckii, is a large, aquatic turtle limited to river systems that drain into the Gulf of Mexico. Previous molecular analyses using both mitochondrial and nuclear DNA suggested that Macrochelys exhibits significant genetic variation across its range that includes three distinct genetic assemblages (weste...

The Alligator Snapping Turtle, Macrochelys temminckii, is a large, aquatic turtle limited to river systems that drain into the Gulf of Mexico. Previous molecular analyses using both mitochondrial and nuclear DNA suggested that Macrochelys exhibits significant genetic variation across its range that includes three distinct genetic assemblages (weste...

In April and May 2000, we conducted surveys for rare vertebrate species on the Fisheating Creek Phase I easement lands, Glades County, FL, which contains ca. 3.3% of Florida’s remaining dry prairie habitat. A large population of gopher tortoises (Gopherus polyphemus) is present, and we documented the gopher frog (Lithobates capito), American crocod...

Three surveys for the South Florida rainbow snake in Fisheating Creek, Glades Co., using a variety of methods in 2012–2013 were unsuccessful at detecting the taxon, which has been petitioned for federal listing as threatened. The last documented specimen was found in 1952, but anecdotal information suggests the population is still extant. Fisheatin...

The eastern indigo snake (Drymarchon couperi) historically occurred in southern Mississippi and Alabama, Georgia, and Florida. old reports from South Carolina are not thought to be credible. Naturally occurring populations likely no longer occur in Mississippi and Alabama, and populations elsewhere are of conservation concern. However, there have b...

A multispecies amphibian larval mortality event, primarily affecting American bullfrogs Lithobates catesbeianus, was investigated during April 2011 at the Mike Roess Gold Head Branch State Park, Clay County, Florida, USA. Freshly dead and moribund tadpoles had hemorrhagic lesions around the vent and on the ventral body surface, with some exhibiting...

Tupinambis merianae is an established invasive lizard in Florida, USA, where a population was discovered initially in Balm Boyette Scrub Preserve, Hillsborough Co. (Enge et al. 2006. In Proceedings 28th Annual Gopher Tortoise Council Meeting. Valdosta, Georgia; Engeman et al. 2011. Curro Zool. 57:599-612). The threats posed by this species to nativ...

In a recent issue of Zootaxa, Krysko et al. (2011) compiled and evaluated vouchers (i.e., specimens and photographs), and confirmed three intercepted and 137 introduced species of non-indigenous amphibians and reptiles in Florida from 1863 through 2010. Trying to improve upon previous methodologies of reporting new non-indigenous species, we stress...

In FY 2008–11, the Striped Newt Survey Team (SNST) surveyed 714 ponds on 38 public conservation lands and on 2 private lands. Striped newts (Notophthalmus perstriatus) were documented in 44 (6.2%) of the ponds, which represented 32 different ponds. Nineteen of these were previously unknown breeding ponds: Ocala National Forest (14), Ordway-Swisher...

We follow a biological invasion model that consists of a series of five consecutive obligatory stages, concluding with stages 4a and 5 (i.e., widespread = invasive species). The State of Florida is infamous for having the most introduced (stages 2-5) amphibians and reptiles in the United States. However, there is disagreement regarding their number...

Key Biscayne (KB) is the southernmost sand barrier island along Florida’s Atlantic coastline located just offshore of Miami, Miami-Dade County, Florida. Although Key Biscayne’s terrestrial fauna is poorly documented, the island has a reputation for being home to a variety of amphibians and reptiles. Herein, we provide historical land use informatio...

Prey items for the federally protected Eastern Indigo Snake (Drymarchon couperi) were compiled from published and gray literature, field observations, necropsies, dissection of museum specimens, and personal communications from reliable sources. One hundred and eighty-six records were obtained for 48 different prey species. Anurans, Gopher Tortoise...

Recovery of the Eastern Indigo Snake (Drymarchon couperi) that is federally listed as threatened will require population monitoring throughout the species' range. From 1998 through 2006, we used mark-recapture methods to monitor D. couperi at Fort Stewart, Georgia, USA. We captured 93 individual D. couperi while surveying for snakes at Gopher Torto...

Recovery of the federally threatened Ambystoma cingulatum (Flatwoods Salamander) will require monitoring of known populations, as well as continued searches for additional populations. In an effort to develop recommendations for maximizing efficiency of future surveys of larval Flatwoods Salamanders, we combined data from surveys conducted between...

Herpetofauna of steephead ravines in the Blackwater and Yellow River drainages, Okaloosa or Santa Rosa County, FL, were surveyed using funnel traps along drift fences. Nineteen amphibian and 24 reptile species in seven steephead ravine sites were documented during 165 days of trapping. Amphibian or reptile species composition was most similar betwe...

A pedestrian survey of snakes was conducted for 1022 days (79% of the available days) along 6 km of rural roads through xeric upland habitats in Hernando County, Florida. Two hundred twenty-eight snakes of 18 species were recorded, 93% of which were dead. The relative abundance of many snake species, such as the rough green snake (Opheodrys aestivu...

In this paper, we discuss the likely modes of introduction of the Knight Anole (Anolis equestris) into and around Florida, pro- vide data on its current geographic distribution, and summarize life history data in both its native and introduced Florida range. Our field data consist of collections made from 1992 through 2008 and locality data taken f...

Basking surveys for Barbour’s map turtle (Graptemys barbouri) in 1999–2001 first documented its occurrence in Florida in the Choctawhatchee River and confirmed its presence in the Ochlockonee River. A total of 294 Graptemys was observed along 145.2 km of the Choctawhatchee River, with highest densities (5–7/km) occurring in the upper reaches north...

In 1990, the Florida Game and Fresh Water Fish Commission’s Nongame Wildlife Program initiated a long-term planning effort to identify and prioritize taxonomic, survey, population monitoring, research, management, habitat protection,and education projects needed to conserve vertebrate wildlife taxa that might be vulnerable to extirpation. Ranking o...

During field surveys in May and June 2004, we confirmed the existence of the non-native butterfly lizard (Leiolepis belliana), in Miami, Miami-Dade County, Florida. We found L. belliana active during the daytime in an area encompassing six square city blocks, where it was observed basking and foraging on open grassy lawns and inhabiting burrows. Th...

The Nile Monitor (Varanus niloticus), the longest lizard in Africa, was first observed in southwestern peninsular Florida in the Cape Coral area of Lee County ca. 1990. From April 2001 through 7 July 2003, we compiled 146 sightings or captures of this species by local residents or ourselves. Numerous individuals of all size classes have been observ...

During field surveys from June 2002 through August 2003, we documented an established population of the veiled or Yemen chameleon (Chamaeleo calyptratus) in Fort Myers, Lee County, Florida. We recorded at least 70 individuals, including both genders and all size classes in consecutive years, indicating a reproducing population. Additionally, ca. 10...

We surveyed the reptile fauna of pine rockland habitat in six Miami-Dade County parks using quadrat sampling in 1996–97 and time-constrained sampling in 2001. Time-constrained sampling detected similar numbers of reptile species per park as quadrat sampling in one-quarter as much time. We detected only 7–8 reptile species per park regardless of par...

We document populations of the introduced African rainbow lizard (Agama agama africana) in Homestead, Miami-Dade County; Hollywood, Broward County; Palm City, Martin County; Punta Gorda, Charlotte County; and Sanford, Seminole County. The Homestead and Punta Gorda populations have been established for over 10 yr and have expanded at least 0.5 km fr...

We document an established population of an Asian agamid lizard commonly called the bloodsucker (Calotes versicolor) in St. Lucie County, Florida. This population was apparently introduced in 1978, and approximately 100 specimens have been captured by two commercial collectors in the past 10 yr. All specimens were captured from nocturnal roosts 1–9...

A program was implemented by the Florida Game and Fresh Water Fish Commission (Commission) on 1 July 1990 to collect information on the scope and magnitude of the commercial trade in native species of amphibians and reptiles in order to better manage this wildlife resource. Data from the first 2 years of the reporting program (1 July 1990 through 3...

The black spiny-tailed iguana (Ctenosuara similis) was introduced onto Gasparilla Island in southwestern peninsular Florida ca. 30 years ago. Since then, this exotic species has undergone both natural and human-mediated range expansion, and it is presently found in Placida, Cape Haze, Gulf Cove, Cayo Costa, Keewaydin Island, and Little Marco Island...

A pedestrian survey of snakes was conducted for 1022 days (79% of the available days) along 6 km of rural roads through xeric upland habitats in Hernando County, Florida. Two hundred twenty-eight snakes of 18 species were recorded, 93% of which were dead. The relative abundance of many snake species, such as the rough green snake (Opheodrys aestivu...

Two seepage bogs in Blackwater River State Forest, Okaloosa County, Flor-ida, were surveyed using funnel traps along drift fences for 165 trapping days from 23 Sep-tember 1998 to 1 September 1999. Fourteen amphibian and 23 reptile species were trapped, and two additional anuran species were heard calling in bogs. Bogs were used by some species from...

The effectiveness of pitfall versus funnel traps was examined using drift fence data from five studies that employed different array designs, fencing materials, and numbers of traps in diverse Florida habitats. In general, salamanders, anurans, lizards, and snakes were captured more frequently than expected in funnel traps than in pitfall traps. In...

We examined summer use of American alligator (Alligator mississippiensis) nests by nesting turtles, principally Florida redbelly turtles (Pseudernys nelsoni), in lakes Okeechobee, Apopka, Griffin, and Jesup during 1986-1991 and in three other wetlands in peninsular Florida for 23 yr. Other turtle species recorded using alligator nests were Apalone...

This report provides a standardized protocol for herpetofaunal surveys using drift fences, including recommended sampling periods and schedules, drift-fence material, and array design. Methodology is given for installing fences; constructing funnel traps; checking traps; processing specimens; inventorying habitat; and recording, entering, managing,...