Phenology and ecology of hibernation in spotted turtles (Clemmys guttata) near the northern limit of their range

Abstract

Using mark-recapture techniques, temperature-sensitive radio transmitters, and miniature temperature data loggers we investigated the hibernation ecology of northern temperate zone spotted turtles (Clemmys guttata) in Georgian Bay, Ontario, over 4 winters (1993-1997). We observed 18 hibernacula that were occupied by 34 turtles; 11 hibernacula were apparently occupied by single turtles, and 7 were used communally by up to 9 individuals. Hibernacula were located in swamps and were of 2 types: sphagnum moss hummock (n = 15) and rock cavern (n = 3). Almost half of the individuals (16 of 34) used the same hibernaculum in at least 2 winters. Turtles entered hibernacula between mid-September and October, when their body temperature was between 12 and 16°C, and exited them in mid to late April, when ambient temperatures ranged between 1 and 5°C. A waterproof temperature data logger attached to a turtle indicated that this turtle was protected from freezing in a thermally stable hibernaculum (body temperature range 0.3-3.9°C) despite highly variable (a 37°C change over 5 days) and low air temperatures (minimum -35°C). Loss of body mass (2%) during hibernation was not significant. We observed no mortality within hibernacula over the 4 winters; however, 3 turtles were destroyed by predators near the hibernacula. These data provide insight into the role of climate in limiting the northern distribution of this species.

Generally specialized or especially general? Habitat selection by Snapping Turtles (Chelydra serpentina) in central Ontario

“…(Schneider, 1792)) (Litzgus et al 1999;Rasmussen and Litzgus 2010), and Wood Turtles (Glyptemys insculpta (LeConte, 1830)) Litzgus 2007, 2008). The selection of cold overwintering sites appears to be a strategy employed by all freshwater turtle species so far tested in northern temperate climates, indicating that there must be a fitness advantage to such thermal behaviour.…”

The ecology of overwintering among turtles: where turtles overwinter and its consequences

“…Small aggregations are common, but groups can contain as many as 34 turtles (Lewis & Ritzenhaler, 1997). A particularly informative study is that of Litzgus et al (1999), who studied spotted turtles near the northern limits of their range in Ontario. They found 11 hibernacula that were used by single turtles and seven communal sites containing up to nine turtles.…”

Population Structure, Growth, and Age Estimation of Spotted Turtles, <em>Clemmys guttata</em>, Near their Northern Limit: an 18-Year Follow-up

“…Other studies of Spotted Turtles also support the notion of multiple hibernation centres. Individuals in one population hibernated in at least three different small bogs (Haxton and Berrill 1999), while in another population 18 hibernacula were found in five different sphagnum swamps (Litzgus et al 1999). Effective management of Spotted Turtle populations should focus on identifying and ensuring the protection of all major hibernacula and the habitat that connects them.…”