Scientific publications

Publication in Urban Ecosystems

Home ranges of box turtles in a rural woodland and an urban park in Saint Louis, MO; implications for turtle conservation

The negative consequences of fragmentation, infrastructure development, and urbanization on biodiversity are well known. However, careful urban planning can provide viable habitat for some species and communities. Generally, r-selected species are more likely to persist in urbanizing landscapes, while long lived, mobile species, such as turtles, are likely to decline toward extinction. Understanding species responses across urban gradients is important for developing mitigation planning. We used VHF telemetry to quantify ranging behavior of three-toed box turtles in fragmented urban forest patches and a semi-contiguous large rural forest in Saint Louis, Missouri. We then simulated movement trajectories based on empirical data from the two turtles with the largest and smallest home ranges, overlaid on forest cover and road network maps of Missouri, to quantify the state-wide probability of turtles encountering roads. Home range (HR) size varied from 1–250Ha. The mean home range estimate of rural turtles was > 9 times larger than that of urban turtles. Simulations indicated that the least mobile turtle (HR 1Ha) would have a 22% likelihood of encountering a road if placed randomly in suitable habitat anywhere in the state. The likelihood increased to 90% for the most mobile turtle (HR 250Ha), with 10 road crossings per year. High turtle mortality, range restriction and population fragmentation are likely even in rural areas. In urban cityscapes, large, roadless forest patches offer the highest conservation potential for this species.

Publication in Human-Wildlife Interactions

No difference in corticosteroneconcentrations between Missouri three-toed box turtles living in an urban and a rural site

Baseline health data for species of conservation concern are important for understanding threats to the long-term viability of populations. One indication of health is physiological stress among individuals. Corticosterone (CORT) is frequently used to quantify stress in free-living reptile populations, as high values may be associated with reduced fitness. Herein, we describe and validate methods for quantifying blood CORT levels in three-toed box turtles (Terrapene mexicana triunguis). We subsequently use this information to evaluate stress levels in 2 populations of free-living three-toed box turtles in Missouri, USA. To our knowledge, this is the first quantification of CORT levels in the three-toed box turtle. In 2012 we collected blood samples from 11 three-toed box turtles in human care at the Saint Louis Zoological Park (zoo), St. Louis, Missouri for assay validation, and from 2012 to 2016 we collected 220 samples from 144 free-living three-toed box turtles at 2 sites, 1 urban and 1 rural. In the zoo turtles, mean CORT concentration was 0.71 ± 0.10 ng/mL. Following a handling experiment, CORT concentration increased to 3.14 ± 0.72 ng/mL (P = 0.011). Mean CORT levels between free-living turtles at the urban and rural sites did not differ (urban = 0.54 ± 0.08 ng/mL, rural = 0.37 ± 0.02 ng/mL, F pr = 0.12). Sex did not influence CORT levels (F pr = 0.29). These results suggest that the turtles living in the urban environment did not experience chronic elevated glucocorticoid production and supports urban parks as potential habitat for box turtles.

Publication in Journal of Wildlife Diseases

Clinical Mycoplasma sp. Infections in Free-living Three-toed Box Turtles (Terrapene carolina triunguis) in Missouri, USA

Mycoplasma species, which can cause upper respiratory tract disease (URTD), are significant pathogens of birds, mammals, fish, and reptiles. Mycoplasmosis is of high concern for chelonian conservation, with the most well- documented cases in gopher and desert tortoises. Mycoplasma sp. infections have been reported in captive and free-living box turtles (Terrapene spp.). We documented URTD associated with Mycoplasma sp. in two free-living, three-toed box turtles (Terrapene carolina triunguis) in Missouri, US. Both turtles were Mycoplasma sp. positive by PCR and had URTD-like clinical signs, including nasal and ocular discharge, palpebral edema, lethargy, and weight loss, during a 6–8-wk period between June and September 2014.