Invasive species are a significant threat to a variety of ecosystems in Florida, with freshwater habitats being of particular concern. Two nonnative species of fish with established populations that are priority organisms for monitoring and management programs are the bullseye snakehead (BS; Channa species complex) and Asian swamp eel (ASE; Monopterus species complex). Recent technological advances have seen the emergence of environmental DNA (eDNA) analysis as a useful tool for the detection and monitoring of target organisms and to assess removal efforts. In this study, a duplex digital polymerase chain reaction (dPCR) was developed, optimized, and validated on control samples and field samples from locations with documented occurrences of target organisms. The assay developed, which allows simultaneous detection of both fish species when present in a sample, demonstrated highly efficient amplification for the corresponding target species with individual assays failing to cross-amplify. Under controlled conditions, high levels of eDNA were detected as early as five minutes post-introduction of BS to water. Additionally, field eDNA samples yielded varying levels of positive amplification for both species based on comparison of fluorescence levels to positive controls (both tissue extract and plasmids with appropriate inserts). These data indicate that through careful assay design and stringent parameter optimization, eDNA results obtained for monitoring of these two fish species can be a viable and cost-effective strategy to detect the presence of these species simultaneously as well as to evaluate the success of removal efforts.

Nonnative species mitigation is important to conserve Florida's native wildlife, especially with nonnative reptiles such as Nile Monitors (Varanus niloticus). Nile Monitors are habitat and dietary generalists in their native (Africa) and nonnative (Florida) ranges and were introduced to Florida in the early 1990s through the pet trade. Nile Monitors have since become established in three coastal counties in southern Florida. Confirmed sightings extend beyond established Nile Monitor populations into parts of central and northern Florida, but it is unclear whether spread is likely to these areas or even into surrounding states. Mitigation strategies to locate, remove, and proactively prevent introduction and spread of nonnative species include species distribution models (SDMs). Two Nile Monitor SDMs currently exist but are not at an appropriate scale to inform regional management practices and include various methods that do not meet current model quality standards. Nile Monitor SDMs here represent high-quality, region-scale predictions at a 1 km2 resolution fitted with ensembles of algorithms, 14 predictors (including environmental and anthropogenic variables), and occurrence data from both the native and nonnative ranges. Final SDM predictions indicate little habitat suitability and low probability of spread beyond the central region of Florida, contradictory to existing Nile Monitor SDMs. Pathways of suitable habitat exist from established populations into other central and southern parts of Florida along coastlines and suggest possible anthropophilic habitat preferences that will require further telemetric behavioral studies to validate.

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 2011-2013, we sampled two 5-km sites in each ER to investigate spatial variation in relative abundance, sex ratio, size-class distribution, and body size of M. suwanniensis. Capture rates and male body sizes were greater in the middle ERs than in the upstream and downstream ERs. Sex ratios were male-skewed only in the middle ERs. Additional research is needed to understand the ecological drivers of M. suwanniensis population dynamics in this river.

Abstract - 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 length, 619 mm maximum carapace width, and 236 mm maximum head width. The turtle was never weighed, but we used morphometric data from our studies in the Santa Fe and Suwannee rivers to estimate that it weighed ∼76.4 kg (168 lbs) when captured. Our 95% prediction interval (67.6–86.3 kg [149–190 lbs]) suggests that speculative estimates and anecdotal reports of M. suwanniensis that weigh ≥90 kg (≥200 lbs) are dubious.

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 the Suwannee River in Florida, USA. We estimated home range size with kernel density estimates (KDE) using the FishTracker GIS toolbox, and we examined potential differences in KDEs with Generalized Linear Models (GLMs). We also used GLMs (family = binomial) to examine habitat selection for M. suwanniensis. We used an information-theoretic approach to rank and select the most parsimonious models. Overall, our models revealed that M. suwanniensis possessed larger 90% KDEs in the LR site than the UR site, and in both sites, turtles moved into the floodplain during flooded conditions. Remarkably, these movements continued even after water levels receded and the aquatic links were severed. Interestingly, M. suwanniensis selected shallow water with some type of subsurface cover, especially large woody debris (LWD). Instream LWD is likely extremely important, especially during low water levels when undercut banks and other bank habitats are unavailable, so the removal of LWD, including deadhead logs, could negatively affect the species. Minimum flows have been established in the drainage, but river water levels have declined an estimated 40% since human settlement, partly because of groundwater withdrawal outside the drainage, potentially imperiling this state Threatened species.

Removal sampling data are the primary source of monitoring information for many populations (e.g., invasive species, fisheries). Population dynamics, temporary emigration, and imperfect detection are common sources of variation in monitoring data and are key parameters for informing management. We developed two open robust-design removal models for simultaneously modeling population dynamics, temporary emigration, and imperfect detection: a random walk linear trend model (estimable without ancillary information), and a 2-age class informed population model (InfoPM, closely related to integrated population models) that incorporated prior information for age-structured vital rates and relative juvenile availability. We applied both models to multiyear, removal trapping time-series of a large invasive lizard (Argentine black and white tegu, Salvator merianae) in three management areas of South Florida to evaluate the effectiveness of management programs. Although estimates of the two models were similar, the InfoPMs generally returned more precise estimates, partitioned dynamics into births, deaths, net migration, and provided a decision support tool to predict population dynamics under different effort scenarios while accounting for uncertainty. Trends in tegu superpopulation abundance estimates were increasing in two management areas despite generally high removal rates. However, tegu abundance appeared to decline in the Core management area, where trapping density was the highest and immigration the lowest. Finally, comparing abundance predictions of no-removal scenarios to those estimated in each management area suggested significant population reductions due to management. These results suggest that local tegu population control via systematic trapping may be feasible with high enough trap density and limited immigration; and highlights the value of these trapping programs. We provided the first estimates of tegu abundance, capture probabilities, and population dynamics, which is critical for effective management. Furthermore, our models are applicable to a wide range of monitoring programs (e.g., carcass recovery or removal point-counts).

- 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 important trophic role in the saltmarsh ecosystem. Population declines are suspected throughout the species' range, and its population status is unknown in Florida. Of the 5 subspecies that inhabit Florida's coastline, the most understudied subspecies may be the ornate diamondback terrapin (M. t. macrospilota). We conducted a capture-mark-recapture study of M. t. macrospilota during the summer of 2013 on 3 adjacent coastal islands in the eastern panhandle of Florida that provided information on population size and demography. We captured 334 individuals; modeling estimated a population size of 1282 (867-1905 95% CI) and a density of 150 terrapins/ha. Population size decreased throughout the study, suggesting that this population is an aggregation that seasonally emigrates from the islands. This emigration trend was more evident for females. Males outnumbered females 4:1, and females were larger than males. Our study is the first to report on M. t. macrospilota populations in the Florida panhandle. We recommend collaborative, long-term population monitoring at our sites to estimate population trends that will be crucial for managing this subspecies.

Nile Monitors (Varanus niloticus) are large (up to 2.4 m in length), semiaquatic, carnivorous lizards native to Sub-Saharan Africa. Nile Monitors are reported from southeastern Florida near the Homestead Air Reserve Base in Miami-Dade County, around Southwest Ranches in Broward County, and from a reproducing population along the C-51 canal in Palm Beach County. This study characterizes the diet of Nile Monitors removed from Palm Beach and Broward counties. In 2012, Florida Fish and Wildlife Conservation Commission staff and University of Florida researchers began conducting monthly boat surveys along the C-51 canal and driving and walking surveys in Southwest Ranches. We used Nile Monitors removed with firearms or live traps from southeastern Florida from 2012 to 2016. We extracted gastrointestinal (GI) tracts and collected gut contents when present. We rinsed, sorted, dried, examined, and identified gut contents to the lowest taxonomic level possible. We examined 68 GI tracts (30 males, 37 females, 1 of undetermined sex) and identified 1,484 prey items from 65 individuals. We categorized prey items as gastropod, diplopod, malacostracan, arachnid, insect, fish, amphibian, reptile, reptile egg, bird, and mammal. Adult Nile Monitors exhibited the highest dietary diversity and evenness among size classes, and there was no observable difference in diet between males and females. Our observations confirm Nile Monitors are active foragers, and the combination of broad diet and active foraging makes it unlikely that food availability will limit distribution of these invasive lizards in Florida.

1Department of Natural Sciences, Santa Fe College, Gainesville, FL 32606 USA <jerry.johnston@sfcollege.edu > 2Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA <dr.joe.mitchell@gmail.com> 3Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611 USA <eric.suarez725@yahoo.com> 4 Karst Environmental Services, High Springs, FL 32643 USA <kes@atlantic.net> 5Florida Springs Institute, Gainesville, FL 32653 USA <bknight@floridaspringsinstitute.org>

The Santa Fe River (SFR) in northern Florida and its springs provide a unique ecosystem for a wealth of flora and fauna, and support a unique freshwater turtle assemblage. We conducted a 6-year mark-recapture study of ten turtle species to assess how habitat heterogeneity among sites affects riverine turtle populations. Because the SFR ecosystem has not been well described and the major emphasis of this paper is the effect of habitat variation on turtle populations, we provide thorough descriptions of the SFR basin and specific habitats in which we sampled turtles. The SFR originates as a tannin-stained blackwater river, but receives substantial input of clear, alkaline, thermally stable water from numerous artesian springs in its lower reaches. We used mark-recapture and demographic data to evaluate differences in turtle assemblages and population structure on a spatial scale. We compared turtle assemblages between a 5 km reach of blackwater river habitat and a 9 km reach of spring-influenced river habitat. We found the same ten species in both habitats. Hand capture while snorkeling suggested similar relative abundance of species in both river habitats, but baited hoop trap captures suggested that Chelydra serpentina (Snapping Turtle) and Sternotherus minor (Loggerhead Musk Turtle) are proportionately more abundant in the three spring-influenced habitats we sampled. The total density of all turtle species combined appears to be three to four times greater in the spring-influenced river reach than in the blackwater river reach. Examination of population structure of the three most abundant species (Pseudemys suwanniensis [Suwannee Cooter], S. minor, and Trachemys scripta [Yellow-bellied Slider]) in the river and adjacent spring habitats revealed that some springs feeding the SFR may function as nursery habitats. Results demonstrate the importance of habitat diversity (beta diversity) to the riverine turtle assemblage. If we had sampled turtles only in one section of the river or only in spring habitats in the lower SFR, our perceptions of assemblages and population structure would have been vastly different. The fate of the turtle populations in the SFR depends on the quantity and quality of water discharging from its springs. If the long-term trend of declining spring flows continues, we predict that SFR turtle populations will be detrimentally affected in multiple ways such as loss of nursery habitat and reduced recruitment. Less dilution of dark tannic water flowing down from the upper SFR may cause shifts in assemblage and population structure, as well as in population densities. Given the uncertain future of ecological conditions in the SFR, we advocate continued long-term monitoring of this unique turtle assemblage.

Macrochelys suwanniensis is a newly described species endemic to the Suwannee River drainage in the southeastern United States. We conducted a study of M. suwanniensis in the Santa Fe River (SFR), the major Florida tributary of the Suwannee River, between 2004 and 2011. We captured 109 individuals (24% immature, 44% adult female, 32% adult male). Adult males (mean straight midline carapace length [CL] = 530.7 mm, mean mass = 34.0 kg) were significantly larger than adult females (mean CL = 424.0 mm, mean mass = 17.2 kg), with a sexual size dimorphism index of 20.25 based on mean CL. The largest turtle in our study was 623 mm CL and weighed 54.4 kg. Adult females were significantly larger (CL) in the lower SFR than in the upper SFR (these reaches are separated where the river flows underground for 5 km). All adult males > 600 mm CL were captured in the lower SFR. Adult females were proportionately heavier in the upper SFR than in the lower SFR; males did not show this difference. We hypothesize that these differences in body size are related to habitat. The M. suwanniensis population in the SFR presently appears healthy, but we suggest this species requires continued protection because of vulnerability of adults to harvest.

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 phylogeo-graphic 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.

Snapping turtles (Chelydra serpentina) occur in nearly every type of freshwater habitat in North America east of the Rocky Mountains, but little is known about the ecology of populations in the southern part of their range, as well as those in lotic habitats. We conducted a mark-recapture study of the Florida snapping turtle (C. s. osceola) in the Santa Fe River in northern Florida between August 2005 and November 2010. Ninety-six percent of all captures occurred within a 9 km section of the river that receives direct input from 21 artesian springs. Within this “high density spring area,” population density and biomass of adults were 2.7 turtles/ha and 24.9 kg/ha, respectively. The total sample (n = 113 turtles) consisted of 14.2% immature individuals, 45.1% adult females, and 40.7% adult males. Adult sex ratio was 1:1. Juveniles occupied spring and spring run habitats disproportionally to the river habitat. Adult males (straight midline carapace length [CL] 243–439 mm, mean = 360 mm) are the largest known in Florida, and adult females (CL 257–380 mm, mean = 325 mm) are similar in size to the largest known conspecifics in Nebraska and South Dakota. The large body sizes in our population are inconsistent with previous studies that indicate a positive relationship between body size and latitude in this species, emphasizing the importance of habitat type in influencing demography. Large body sizes in the Santa Fe River may be related to the thermal/food resources provided by artesian springs, the physical environment of the riverine habitat, or coexistence with alligator snapping turtles (Macrochelys temminckii).

The endemic Antillean family Leiocephalidae includes 28 currently recognized extant species in the genus Leiocephalus. These are distributed across Hispaniola, Cuba, and various islands and cays in the Bahamas. Sexual size dimorphism (SSD) is a fundamental and widespread biological phenomenon generally attributed to sexual differences in relationships between body size, survival, fecunditty, and mating success. Six species with 40 subspecies are known from Cuba. Few data are available regarding SSD and reproduction. Herein we report new life-history data and the sexual size dimorphism index (SSDI) in Leiocephalus macropus asbolomus. Fieldwork was performed during mid-August 2009 iin La Melba (Alexander von Humboldt National Park), HolguinProvince, Cuba. All males were larger in size then females and the SSDI (1.44) is the highest reported ffor any species of Leiocephalus. Egg measurments averaged 18.2 x 12.7 mml mean clutch size was 3. Eggs took 61-72 days to hatch; mean incubation time was 66.5 days, and mean hatchling SVL was 30.1 mm.

From 2–4 April 2010, KlK and sAJ took six students from their University of Florida’s Invasion ecology of Amphibians and Reptiles class on a field trip to southern Florida. on 4 April 2010 at 1145–1230 h, under mostly sunny skies, 25 °C, 57% humidity, and 12 mph ese winds, we visited a warehouse district across the street from where a reptile dealer was formerly in business in port st. lucie, st. lucie County, Florida. We surveyed a 4-block area from a vacant lot at n 27.29225° W -80.36766° (datum WGs84) to the north, sW sea holly terrace to the south, sW biltmore street to the east, and sW south macedo boulevard to the west. on 20 June 2010 from 1045–1130 h, under mostly sunny skies, 32 °C, 66% humidity, and 10.4 mph e winds, KlK, Jpb, and CAs revisited this site. specimens were collected opportunistically by hand and deposited in the Florida museum of natural history (Flmnh), University of Florida (UF) collection. We discovered a previously undocumented introduced lizard species, identified as the African Five-lined skink, Trachylepis quinquetaeniata (lichtenstein 1823). Digital images of our live and preserved specimens, along with additional images of live animals that were not collected, were sent to colleagues who confirmed our identification (W. böhme and A.m. bauer, pers. comm.). During our initial 45-min daytime survey on 4 April 2010, we recorded 46 different juveniles and adults, suggesting reproduction and a well-established population. lizards were readily observed basking on concrete slabs and curbs, in asphalt parking lots, along buildings, and at the bases of trees, but we also found individuals under concrete slabs and wooden boards. When pursued, most of the lizards ran swiftly under debris or escaped into holes in the sides of buildings. one individual climbed >4.5 The african five-lined skink, Trachylepis quinquetaeniata (lichtenstein 1823): a new established species in florida