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Since the early 1990s, morbidity and mortality in tortoise populations have been associated with a transmissible, mycoplasmal upper respiratory tract disease (URTD). Although the etiology, transmission, and diagnosis of URTD have been extensively studied, little is known about the dynamics of disease transmission in free-ranging tortoise populations . To understand the transmission dynamics of Mycoplasma agassizii , the primary etiological agent of URTD in wild tortoise populations, we studied 11 populations of free-ranging gopher tortoises ( Gopherus polyphemus ; n = 1667 individuals) over five years and determined their exposure to the pathogen by serology, by clinical signs, and by detection of the pathogen in nasal lavages. Adults tortoises ( n = 759) were 11 times more likely to be seropositive than immature animals ( n = 242) (odds ratio = 10.6, 95% CI = 5.7-20, P < 0.0001). Nasal discharge was observed in only 1.4% (4/296) of immature tortoises as compared with 8.6% (120/1399) of adult tortoises. Nasal lavages from all juvenile tortoises ( n = 283) were negative by PCR for mycoplasmal pathogens associated with URTD. We tested for spatial segregation among tortoise burrows by size class and found no consistent evidence of clustering of either juveniles or adults. We suggest that the social behavior of tortoises plays a critical role in the spread of URTD in wild populations, with immature tortoises having minimal interactions with adult tortoises, thereby limiting their exposure to the pathogen. These findings may have broader implications for modeling horizontally transmitted diseases in other species with limited parental care and emphasize the importance of incorporating animal behavior parameters into disease transmission studies to better characterize the host-pathogen dynamics.

A study was conducted in 2009 to gather information on long-term gopher tortoise (Gopherus polyphemus) population dynamics, burrow distribution, and habitat use at Plum Creek/Lochloosa, a pine (Pinus elliottii; Pinus palustris) plantation in northern Florida. Mark–recapture surveys were conducted on this study site during the 1980s, and a follow-up survey was done in 1992. The ca. 66-ha study area is a mosaic of moderately well-drained and poorly drained soils, and it has had a history of clear-cutting and replanting. Recent management activities included a tree thinning in 2008 and a controlled burn in winter 2009. We located gopher tortoise burrows during late April and early May 2009, and captured tortoises in pitfall or wire traps during May–July. Fifty-two tortoises were captured on the study site and 4 others in an adjacent pine plantation across a paved rural road. Seventeen of the tortoises (33%) had been previously marked, including a male marked as a mature adult in 1982. Most (88%) marked individuals were found in the same approximate location (within 200 m) as during earlier surveys, despite the silviculture-related habitat changes over time. Only 8% of all marked (n  =  211) tortoises were recaptured in 2009. Recapture rates were 4% for tortoises marked when immature, 10% for adult males, and 21% for adult females. Drill marks held up relatively well in adult tortoises but were difficult to discern in some tortoises marked as juveniles. Size and sex class distributions of tortoises captured in 2009 were different from those observed during 1981–1987 and 1992, primarily because fewer juveniles were captured in 2009. This follow-up survey indicated that viable gopher tortoise populations can persist on sites undergoing intensive silviculture, and it further substantiated tortoise use of windrow berms, ecotones, and relatively well-drained soils.

Information regarding the harvest of eastern diamondback (Crotalus adamanteus) and timber (C. horridus) rattlesnakes was gathered from commercial dealer reports, phone interviews with dealers and collectors, and examinations of 714 harvested rattlesnakes. Many individuals killed and sold rattlesnakes in north Florida, but relatively few sold snakes repeatedly, and most brought in one snake per visit to a dealer. Collection occurred primarily during the spring, summer, and fall. Most of the 98 interviewed collectors opportunistically killed rattlesnakes on roads, in yards, and, less commonly, in woods; only five indicated that they actively hunted for rattlesnakes. Many interviewees indicated that they would kill rattlesnakes that they encountered, especially near human habitations, regardless of any potential monetary gain. Eightyfour percent of the 714 rattlesnakes examined at a north Florida skin processing facility were C. adamanteus and 16% were C. horridus. Sex ratios were skewed towards males in both species. Mean snout-vent lengths for males and females were comparable, but males attained greater maximum snout-vent lengths. Twentynine percent of females in both species were reproductively active. Mean litter size was 13.8 for 27 C. adamanteus and 10.6 for seven C. horridus. Snout-vent lengths of the smallest mature females were 109.3 cm for C. adamanteus and 109.9 cm for C. horridus.

Blood samples were collected from 386 gopher tortoises (Gopherus polyphemus) on 53 sites in Florida to determine exposure to a pathogen (Mycoplasma agassizii) that causes upper respiratory tract disease (URTD). One-hundred fourteen (30%) of the tortoises were seropositive, indicating that they had been exposed to mycoplasma and had developed a detectable immune response. Another 20 (5%) were considered suspect. The remaining 252 (65%) tortoises were seronegative. The 114 seropositive tortoises were from 14 locations, 12 of which were public lands. Thirty-nine percent of the 386 tortoises showed one or more clinical signs of URTD. Nasal lavage samples were collected from 89 tortoises on eight of the 53 sites. Four tortoises (4%) from three sites were positive, indicating presence of mycoplasma. A different mycoplasma was indicated on each of the three sites.

In 1995, we surveyed a previously studied (1982–1986) northern Florida population of Gopherus polyphemus (Gopher Tortoise) to document demographic changes that may have occurred over time. The sandhill study site had been unburned for approximately 8 years, resulting in increased woody midstory and decreased herbaceous groundcover. We captured 88 Gopher Tortoises in pitfall traps during May—June 1995. Eighteen (20%) of the tortoises had been previously marked; only 11% of 169 marked tortoises were recaptured. Gopher Tortoise distribution appeared to be more clumped in 1995, and density had declined by about half, likely due to habitat degradation associated with fire exclusion. Size- and sex-class distribution and clutch size were not significantly different between the two study periods. In 1995, the smallest female with detected shelled eggs had 11 plastral annuli and a carapace length of 225 mm. Habitat degradation, whether on private or public lands, is an ongoing problem for this species.

A significant gopher tortoise (Gopherus polyphemus) mortality event was documented in June 1998 at a 150-ha mitigation park established for tortoise protection. Shell surveys throughout the park were conducted between June 1998 and September 1999. The greatest concentration of dead tortoises, as determined by shells and remains, occurred on a 28-ha portion of the park, where 104 individual shells were recovered. Tortoise age class and sex were recorded, with results indicating 68% of shells were of adult males. In an attempt to estimate time since death, shells were assigned to one of 6 condition classes, based on degree of disarticulation. Burrow surveys conducted as a means of obtaining tortoise density estimates showed major declines in population size between December 1994 and June 1998 in the area of highest mortality. Potential causes of death and management implications are discussed.