Turtles Flashcards
What is a turtle?
An ectothermic animal, specifically a reptile which lays eggs, that has a shell called a carapace that is made up of plates or scutes of bone that protects the animal’s internal organs.
What is the bottom part of a turtle’s shell called?
Plastron
What is the difference between a turtle and a tortoise?
Turtles are aquatic and tortoises are land-dwelling.
How do turtles maintain buoyancy?
By adjusting the amount of air in their lungs and the amount of water in their cloacal bursa.
(Jackson, 2011)
What does basking do to a turtle?
It increases the rate of chemical reactions within the turtle and subsequently its metabolism.
It also lowers the pH level and increases the CO2 level of the turtle’s blood.
(Jackson, 2011)
What DO levels can snapping turtles withstand? When is this most important?
They have been found to hibernate in a wide range of dissolved oxygen levels (e.g., 0.55–15.63 mg/L).
Dissolved oxygen levels impact turtles the most during the winter.
(G. P. Brown & Brooks, 1994; Marshall et al., 2021).
What is the home range of a snapping turtle?
Their home ranges vary by season and by sex with females having larger home ranges .
One study in Ontario found the home range to be anywhere from 0.95 to 8.38 ha.
(Obbard & Brooks, 1981; Paterson et al., 2012)
What is the scientific name for the snapping turtle?
Chelydra serpentina
Where do turtles fit in the food web?
As a group, turtles occupy trophic positions as herbivores, carnivores, and omnivores and play important, even dominant, roles in their communities, sometimes as a top predator.
(Lovich et al, 2018)
Why are turtles important to ecosystems?
- They normally (pre-humans) contribute a lot of biomass meaning they have a large impact on the ecosystem with their numbers.
- Contribute to energy flow in their immediate and surrounding environment.
(e.g., eggs = flow from aquatic to terrestrial via predation and into soils, as consumers they remove carrion) - Contribute to mineral cycling.
(e.g., lots of Ca in their bones) - Environmental indicators - long-lived so accumulate toxins.
- Important members of food web and their removal can cause trophic cascades.
- Important agents for seed dispersal.
- Important in bioturbation by contributing to soil processes including its formation, function, and maintenance.
- The ability of some turtles to survive in polluted waterways could potentially make them useful for restoration.
(Lovich et al, 2018)
Why is it especially sad that turtles are so threatened?
Turtles are an ancient group going back over 200 million years - they predate mammals and birds and outlived the dinosaurs.
Showing they’ve been able to outlive tons of things thrown at them, yet can’t survive modern humans.
(Lovich et al, 2018)
Why are turtles so threatened?
- A global focus by conservation programs to prioritize and target areas that protect birds and mammals but do not adequately consider turtle diversity….ok for turtles with larger ranges but not smaller ones.
- Habitat loss and degradation
(e.g., forest loss, agriculture, water quality. hardening of shorelines, removal of logs/basking/prey sites) - Disease
- Over-collection of turtles and their eggs for food consumption and the international pet trade, as well as over-collection for the trade in traditional medicines made from turtle parts
- Climate change (many turtles have environmental sex determination)
- Invasive species
(e.g., severely increased egg predation by invasive predators)
(Cox et al, 2022; Lovich et al, 2018; Stanford et al, 2020)
How can further turtle extinctions be prevented?
Protect remaining habitat, especially 16 hotspots.
Lower consumption of turtles and eggs including bycatch.
Captive breeding and reintroductions.
Enforcement of new and existing laws.
More research.
Engage locals.
(Stanford et al, 2020)
What habitat do snapping turtles prefer?
Turtles in general have a high preference for using wetlands globally.
Snapping turtles are capable of living in most freshwater habitats within its range but show a preference for muddy bottoms.
(Cox et al, 2022; West, 2008)
Describe how life history traits relate to catastrophic events.
How does this relate to turtles?
Provide example.
Populations with faster life histories are more vulnerable to perturbations in reproductive success, whereas those with slow life histories are most sensitive to adult survivorship and thus take longer to recover from depletion.
Turtles typify the slow end of the life-history spectrum, exhibiting iteroparity, high adult survivorship, and low and variable juvenile recruitment. Populations of organisms with slow life-history strategies are vulnerable to even small decreases in adult survivorship, with as little as a 2–3% reduction in survivorship resulting in severe population decline.
e.g., 23 year study done by Mathew Keevil & others in 2018 on snapping turtles in Algonquin park after predation catastrophe showed that
their survivorship was the same before the incident but their abundances did not increase after the catastrophe even though it was a long enough timeframe that offspring after the catastrophe would have been recruited. They estimated it could take 59 years to see any recovery.
(Keevil et al, 2018)
