Terrestrial habitat requirements of nesting freshwater turtles

Abstract

Because particular life history traits affect species vulnerability to development pressures, cross-species summaries of life history traits are useful for generating management guidelines. Conservation of aquatic turtles, many members of which are regionally or globally imperiled, requires knowing the extent of upland habitat used for nesting. Therefore, we compiled distances that nests and gravid females had been observed from wetlands. Based on records of > 8000 nests and gravid female records compiled for 31 species in the United States and Canada, the distances that encompass 95% of nests vary dramatically among genera and populations, from just 8 m forMalaclemys to nearly 1400 m for Trachemys. Widths of core areas to encompass varying fractions of nesting populations (based on mean maxima across all genera) were estimated as: 50% coverage = 93 m, 75% = 154 m, 90% = 198 m, 95% = 232 m, 100% = 942 m. Approximately 6-98 m is required to encompass each consecutive 10% segment of a nesting population up to 90% coverage; thereafter, ca. 424 m is required to encompass the remaining 10%. Many genera require modest terrestrial areas (zones) for 95% nest coverage (Actinemys, Apalone, Chelydra, Chrysemys, Clemmys,Glyptemys, Graptemys, Macrochelys, Malaclemys, Pseudemys, Sternotherus), whereas other genera require larger zones (Deirochelys, Emydoidea, Kinosternon, Trachemys). Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings. Our results represent planning targets for conserving sufficient areas of uplands around wetlands to ensure protection of turtle nesting sites, migrating adult female turtles, and dispersing turtle hatchlings.

Biological invasions and natural colonisations are different – the need for invasion science

“…The maximum recorded dispersal distance of nesting females is 1.4 km (Steen et al 2012;Garcia-Diaz et al 2015). Yet, since the 1960s, the species has been introduced to 77 countries around the world, establishing self-sustaining populations in 36 countries (i.e.…”

Survey methodology for the detection of Wood Turtles (<em>Glyptemys insculpta</em>)

“…unless they are nesting, semi-aquatic turtle species, such as Painted Turtles (Chrysemys picta), northern Map Turtles (Graptemys geographica), and Snapping Turtles (Chelydra serpentina), generally remain in or next to a waterway (gamble and Simons 2004;carrière and blouin-Demers 2010;Patterson et al 2012;Steen et al 2012), resulting in a more defined and restricted survey area and increased confidence that detection is likely within a set distance from water.…”

“…in canada, they are found in parts of south-central ontario and southern Quebec (Desroches and Rodrigue 2004; committee on the Status of endangered Wildlife in canada 2008*), new brunswick, and nova Scotia (Mcalpine and gerriets 1999;gräf et al 2003;biggar 2008*) because the Wood Turtle is a listed species, surveys to establish the presence of Wood Turtles are often included in environmental assessments and regulatory per mitting for new development projects and road construction (e.g., aMec 2002*; Macgregor and elderkin 2003*; Saumure 2007*). Road mortality is a major threat to Wood Turtle viability (gibbs and Shriver 2002;MacKinnon et al 2005;Steen et al 2006Steen et al , 2012 because the extensive terrestrial movements of Wood Turtles bring them into contact with roads and exceed the traditional, narrow (e.g., 15 m) riparian buffer protection zones often required in forested and agricultural landscapes (Tingley et al 2009). accurate information on the presence of Wood Turtles could be applied to mitigating development projects and influencing the alignment and design of new roads (langen et al 2012).…”

“…Throughout its range, surveys for the Wood Turtle have been conducted during spring (Quinn and Tate 1991;Saumure and bider 1998;arvisais et al 2002;Dubois et al 2008Dubois et al ), autumn (compton et al 2002greaves and litzgus 2007), or multiple seasons (Jones et al 2012). The width of the survey area varies.…”

“…The united States Forest Service recommends a survey using three people, one person on either side of the waterway surveying the banks, and one on foot, or possibly a canoe, in the centre of the river (bowen and gillingham 2004*). a standardized survey protocol being developed for the Wood Turtle in new england requires one or two observers with non-overlapping tracks searching within 10 m of a shoreline 1 km in length for 2 hours, three times within a three-week period (Jones et al 2012*). The number of surveyors over an area 10-15 m from a stream in Quebec varied between one and ten people (arvisais et al 2002), although most surveys are now conducted by a person on each shore and one in a canoe (Daigle 1996*).…”