Spatial Ecology and Abundance of Turtles in Grundy Lake Provincial Park

Abstract

Across the globe biodiversity is being lost at an unprecedented and unsustainable rate. The loss of biodiversity has direct and negative impacts on food production and other critical ecosystem services, to such a degree that we are currently experiencing a mass extinction event. Turtles are a group of vertebrates whose slow life histories and high juvenile mortality rates make them especially vulnerable to environmental changes. Anthropogenic climate change, habitat loss, and vehicle mortality are just a handful of factors responsible for an estimated 60% of turtle species being extinct or threatened with extinction. In Ontario there are currently eight native species of freshwater turtle, each are classified federally or provincially as at-risk species. Ontario represents the northern range periphery of these turtles presenting unique challenges including shorter active seasons and harsher winter weather. Grundy Lake Provincial Park is a protected area east of Georgian Bay Mnidoo Gamii in central Ontario. The three most common turtle species found in the park are the Blanding’s turtle, painted turtle and snapping turtle. Grundy Lake Provincial Park may be a stronghold for the globally endangered Blanding’s turtle, because of this in Chapter 2 we examined the spatial ecology of Blanding’s turtles at Grundy Lake Provincial Park by evaluating (1) habitat use, (2) home range and space use areas, (3), habitat selection, (4) minimum daily distance travelled, and (5) travel corridor identification. We found that both sex and behavioural season significantly impacted the spatial ecology of Blanding’s turtles, especially females during the nesting season. We identified travel corridors and areas of high-use in the park, highlighting areas important for habitat connectivity and nesting migrations. In Chapter 3, we examined population abundance and nesting distribution of all three species of freshwater turtle; our goal was to (1) estimate population abundance, (2) estimate somatic growth rate, (3) determine areas of high nest density, (4) evaluate carapace length distribution, and (5) estimate biomass and density. We estimated an abundance of 183 adult female painted turtles, 100 adult Blanding’s turtles and 63 adult female snapping turtles. Across species, somatic growth rate was greater in juveniles compared to adults. There was evidence of sexual size dimorphism in painted and Blanding’s turtles. Biomass and density estimates were highest for snapping turtles despite a low population estimate, emphasizing their role in the ecosystem. The turtle population in Grundy Lake Provincial Park represents an important stronghold near their northern range limit and offers a critical opportunity for long-term research in a protected area.