Kevin M. Enge

A PEDESTRIAN ROAD SURVEY OF AN UPLAND SNAKE COMMUNITY IN FLORIDA

Abstract 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 aestivus) and southern hognose snake (Heterodon simus), differed between the road survey and three drift fence surveys in xeric upland habitats that trapped 22 species. The pedestrian road survey was successful at detecting small snake species and neonates. Mean annual mortality of all snake species was 12.8/km/yr, despite low traffic volume on the roads surveyed, and 70% of carcasses remained on roads for <1 day. Peak periods of snake activity were June–July and September–November. Snakes were not found along roads in proportion to the coverage of four natural and three ruderal habitat types; snakes were found proportionally less frequently adjacent to lawns and improved pastures. Some snake species, such as the southern hognose snake, can apparently persist in areas of fragmented and altered upland habitats, but this study suggests that loss and degradation of natural habitats may have long-term impacts on populations of large snake species. Roads may be a significant source of mortality for some snake populations, especially for dispersing neonates, which comprised 80% of road-killed snakes in September–December.

Status of the Nile Monitor (Varanus niloticus) in Southwestern Florida

Abstract 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 observed or collected, suggesting the occurrence of a reproducing population. Although our records are mostly confined to Cape Coral, our data indicate that V. niloticus has recently expanded its range northwards and to nearby islands. Because this large lizard has the potential to disperse into nearby ecologically sensitive areas and preserves where it could pose a serious threat to waterbirds, Burrowing Owls (Athene cunicularia), sea turtles, and other native wildlife, population monitoring and eradication are warranted.

Prey Records for the Eastern Indigo Snake (Drymarchon couperi)

Abstract 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 Tortoises, snakes, and rodents comprised ca. 85% of the prey items. Most records (n = 143) that mentioned size were from adult indigos; 17 were from juveniles. Prey records were collected from 1940–2008 and were available for all months of the year. These data confirm that Eastern Indigo Snakes eat a wide assortment of prey of varying sizes. This strategy allows D. couperi to potentially forage successfully in many different types of habitats and under fluctuating environmental conditions, a valuable trait for a top-level predator that requires a large home range.

Taxonomic assessment of Alligator Snapping Turtles (Chelydridae: Macrochelys), with the description of two new species from the southeastern United States.

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 (western, central, and eastern = Suwannee). However, no taxonomic revision or morphological analyses have been conducted previously. In this study, we test previous hypotheses of distinct geographic assemblages by examining morphology, reanalyzing phylogeographic genetic structure, and estimating divergence dating among lineages in a coalescent framework using Bayesian inference. We reviewed the fossil record and discuss phylogeographic and taxonomic implications of the existence of three distinct evolutionary lineages. We measured cranial (n=145) and post-cranial (n=104) material on field-captured individuals and museum specimens. We analyzed 420 base pairs (bp) of mitochondrial DNA sequence data for 158 Macrochelys. We examined fossil Macrochelys from ca. 15-16 million years ago (Ma) to the present to better assess historical distributions and evaluate named fossil taxa. The morphological and molecular data both indicate significant geographical variation and suggest three species-level breaks among genetic lineages that correspond to previously hypothesized genetic assemblages. The holotype of Macrochelys temminckii is from the western lineage. Therefore, we describe two new species as Macrochelys apalachicolae sp. nov. from the central lineage and Macrochelys suwanniensis sp. nov. from the eastern lineage (Suwannee River drainage). Our estimates of divergence times suggest that the most recent common ancestor (MRCA) of M. temminckii (western) and M. apalachicolae (central) existed 3.2-8.9 Ma during the late Miocene to late Pliocene, whereas M. temminckii-M. apalachicolae and M. suwanniensis last shared a MRCA 5.5-13.4 Ma during the mid-Miocene to early Pliocene. Examination of fossil material revealed that the fossil taxon M. floridana is actually a large Chelydra. Our taxonomic revision of Macrochelys has conservation and management implications in Florida, Georgia, and Alabama.

Herpetofaunal Drift-fence Surveys of Steephead Ravines in the Florida Panhandle

Abstract 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 between steephead ravines in the Blackwater and northern Yellow River systems, which were in close proximity. Ravines in the northern Yellow River system, however, were unique in apparently lacking Dusky Salamanders (Desmognathus sp.). Herpetofaunal species composition among ravines was somewhat similar to that found in ravines farther east in the Apalachicola and Ochlockonee River drainages, but 12 species were trapped only in Ochlockonee–Apalachicola ravines and 13 species only in Blackwater–Yellow ravines. The first month of trapping experienced heavy rainfall from Hurricane Georges and produced 76% of all captures of Pseudotriton ruber (Red Salamanders) and three aquatic salamander species. Amphibian captures, particularly salamanders, were correlated positively with precipitation. The most productive trapping months were April, June, and August for anurans; February and October for salamanders; and April and June for reptiles. Mean recapture rates were 8.6% for anurans, 6.8% for salamanders, 52.2% for turtles, 17.3% for lizards, and 9.8% for snakes. Data were collected on some little-known species: Rana okaloosae (Florida Bog Frog), Amphiuma pholeter (One-toed Amphiuma), and Siren cf. intermedia (“Least” Siren). Potential threats to ravine herpetofauna are logging, water pollution, groundwater use, stream siltation from dirt roads and cleared lands, stream impoundment, recreational use, trash dumping, Sus scrofa (feral hogs), and management of adjacent upland habitat.

Capture Rate, Body Size, and Survey Recommendations for Larval Ambystoma cingulatum (Flatwoods Salamanders)

Abstract 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 1990 and 2004 in Florida and Georgia. Analysis of these data revealed variation in the number of larvae captured, survey effort, capture rates, and larval body size among years and months. An average of 16 min or 45 one-m long dipnet sweeps was required to catch each larva. For wetlands surveyed twice in a season, results (i.e., larval presence or assumed absence) were consistent in 74% of consecutive surveys. We make recommendations for conducting future surveys and the implementation of a coordinated research and monitoring program for Flatwoods Salamanders.

Reproduction of the Burmese python (Python molurus bivittatus) in southern Florida

Kenneth L. Krysko1,5, James C. Nifong1, Ray W. Snow2, Kevin M. Enge3, Frank J. Mazzotti4 1 Florida Museum of Natural History, Division of Herpetology, University of Florida, Gainesville, Florida 32611, USA 2 Everglades National Park, 40001 State Road 9336, Homestead, Florida 33034, USA 3 Florida Fish and Wildlife Conservation Commission, 4005 South Main Street, Gainesville, Florida 32601, USA 4 Department of Wildlife Ecology and Conservation, University of Florida, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA 5 Corresponding author; e-mail: kenneyk@flmnh.ufl.edu