Survey of State-Listed Reptiles in the Florida Keys
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Survey of State-listed Reptiles in the Florida Keys FINAL REPORT Jonathan D. Mays and Kevin M. Enge October 31, 2016 Reptile and Amphibian Subsection Fish and Wildlife Research Institute Florida Fish and Wildlife Conservation Commission 1105 SW Williston Rd. Gainesville, FL 32601 FINAL REPORT Reptile and Amphibian Subsection Wildlife Research Section Fish and Wildlife Research Institute Florida Fish and Wildlife Conservation Commission Project Title: Survey of State-listed Reptiles in the Florida Keys Project Number: 9241-295-1313 Project Duration: July 2015 to October 2016 Principal Investigators: Jonathan Mays and Kevin Enge, Florida Fish and Wildlife Conservation Commission, FWRI, Wildlife Research Section, Reptile and Amphibian Subsection, 1105 S.W. Williston Road, Gainesville, FL 32601 Cooperators: Adam Emerick (USFWS), Pierson Hill (FWC-FWRI), Kenneth Krysko (FLMNH), Ricardo Zambrano and Carol Rizkalla (FWC- HSC), Prepared By: Jonathan Mays and Kevin Enge Date Submitted: 31 October 2016 Survey of State-listed Reptiles in the Florida Keys 2 TABLE OF CONTENTS INTRODUCTION ......................................................................................................................... 6 Environment ................................................................................................................................ 6 Target Reptile Taxa ..................................................................................................................... 7 Objectives ................................................................................................................................... 8 METHODS .................................................................................................................................... 8 RESULTS .................................................................................................................................... 10 DISCUSSION .............................................................................................................................. 12 ACKNOWLEDGMENTS .......................................................................................................... 14 LITERATURE CITED .............................................................................................................. 15 FIGURES AND TABLES .......................................................................................................... 17 “Report Reptiles in the Florida Keys” website ......................................................................... 17 Outreach flyer #1 ...................................................................................................................... 18 Outreach flyer #2 ...................................................................................................................... 19 Lower Keys Coverboard Sites .................................................................................................. 20 Lower Keys Driving Surveys .................................................................................................... 21 Numbering scheme for striped mud turtles ............................................................................... 22 All reptile and amphibian observations, by survey method ...................................................... 23 Striped mud turtle survivalbility, detectability, population growth rate, and population size .. 24 Striped mud turtle location map and monthly observations histogram .................................... 25 Florida Keys mole skink location map and monthly observations histogram .......................... 26 Keys ringneck snake location map and monthly observations histogram ................................ 27 Red rat snake location map and monthly observations histogram ............................................ 28 Florida brown snake location map and monthly observations histogram ................................. 29 Survey of State-listed Reptiles in the Florida Keys 3 Rim rock crowned snake location map and monthly observations histogram .......................... 30 Eastern ribbon snake location map and monthly observations histogram ................................ 31 APPENDIX I – New island records for reptiles in the Florida Keys ..................................... 32 APPENDIX II – Reptile and amphibian species list of state park surveys ........................... 37 PHOTOS ...................................................................................................................................... 38 Terrestrial habitats .................................................................................................................... 38 Aquatic habitats ........................................................................................................................ 39 Coverboard sites ........................................................................................................................ 40 Field methods ............................................................................................................................ 41 Survey of State-listed Reptiles in the Florida Keys 4 EXECUTIVE SUMMARY One turtle, 1 lizard, and 5 snake taxa in the Florida Keys are currently state listed, and 5 of these taxa have been proposed for federal listing. Many locality records are old, and subsequent habitat alteration and hurricanes have affected populations and their distribution. We conducted a 1-year study to collect updated occurrence records, determine effective survey methods, assess the status of historical localities, and collect genetic samples for future taxonomic studies. Public outreach efforts, including an FWC website developed to solicit sightings, produced 75 reports of target taxa (10 mud turtles, 8 mole skinks, 10 ringneck snakes, 35 red rat snakes, 1 brown snake, and 11 ribbon snake records). Monthly visits for 1 year produced 164 records of target taxa. Seventy-three records of 3 target taxa came from road (12 striped mud turtles, 23 red rat snakes, and 7 ribbon snakes) or pedestrian (8 striped mud turtles, 11 red rat snakes, and 12 ribbon snakes) surveys, whereas 192 coverboards produced only 8 mole skinks and 2 ringneck snakes. Targeted surveys for the striped mud turtle (turtle trapping) and Florida Keys mole skink (raking) produced 62 and 19 individuals, respectively. We were unsuccessful at detecting the rim rock crowned snake and at developing effective methodologies to use in future surveys of the Keys ringneck snake, brown snake, and rim rock crowned snake. Sufficient data could be collected on the striped mud turtle and red rat snake to determine their population status, although our observations suggest both are doing well, despite experiencing road mortality. Future work targeting the Florida Keys mole skink or ribbon snake has potential, but detection of both species is highly weather dependent. A biologist at National Key Deer Refuge will be incorporating our methodologies to conduct a more extensive coverboard study that will provide more data on the effectiveness of this survey technique. Survey of State-listed Reptiles in the Florida Keys 5 INTRODUCTION Environment The Florida Keys are a chain of approximately 1,700 small, narrow limestone islands that stretch in a gentle arc southwesterly for ca. 220 km from the southeastern tip of peninsular Florida. Based upon geology, the Upper Keys extend about 175 km from Soldier Key to Newfound Harbor Channel on the eastern side of Big Pine Key, and the Lower Keys extend about 50 km from Big Pine Key to Key West (Hoffmeister and Multer 1968). However, we consider the Lower Keys, which we targeted for surveys, to extend from Little Duck Key to Key West. The 11 km between Knight’s Key (Upper Keys) and Little Duck Key is spanned by Seven Mile Bridge and probably represents a dispersal barrier for many terrestrial species. The unconnected Marquesas Keys are an undeveloped group of mangrove-covered islands located ca. 30 km west of Key West. The Dry Tortugas are a small group of 7 islands (4 islands disappeared during hurricanes) located ca. 100 km west of Key West. The Upper and Lower Keys were formed by 2 different processes that created different geological formations, hydrology, topography, and land forms (Hoffmeister and Multer 1968). The surface rock of the Upper Keys is composed of Key Largo limestone that was formed by ancient coral reefs when sea level was estimated to be 6−8 m higher than today and all of southern Florida was inundated (Perkins 1977). Key Largo limestone extends from Miami Beach south throughout the entire Florida Keys, and west to the Dry Tortugas, where it is found ca. 9 m below sea level (Hoffmeister and Multer 1968). The surface rock of most of the Lower Keys is made up of Miami oolitic limestone (oolitic facies) that overlays the underground foundation of Key Largo limestone at a low angle in a southerly direction (Hoffmeister and Multer 1968). A contact zone exists on southeastern Big Pine Key, and the dividing point between the two limestone formations is found at the Newfound Harbor Channel (Hoffmeister and Multer 1968). Miami oolite is an ancient, underwater, east-west shoal of unstable oolite that grew mainly by a chemical process as calcium carbonate crystals formed and precipitated out of warming salt water (Hoffmeister and Multer 1968). The biogenic origin of Miami oolite can be observed in the northwest to southeast orientation and shape of the islands, and the lower, more uniform