Assessment of critical habitat for common snapping turtles (Chelydra serpentina) in an urbanized coastal wetland

  • Morgan L. PiczakEmail author
  • Patricia Chow-Fraser


Critical habitats such as nesting areas and overwintering sites are specific areas used by organisms to carry out important life functions. In many urbanized centers, critical habitats of at-risk species have often become degraded and/or fragmented because of human activities. Such is the case for the population of common snapping turtles (Chelydra serpentina) in Cootes Paradise Marsh, a highly urbanized ecosystem located at the western tip of Lake Ontario. In addition to these threats, mortality from collisions with cars on a four-lane highway at the western end of the marsh has greatly reduced wildlife populations. Here, we examine long-term changes in critical habitat distribution that has accompanied urbanization of Cootes Paradise Marsh from 1934 to 2010. We delineated potential nesting habitat for snapping turtles in 7 digitized aerial photos, using literature information and 2017 nesting surveys as guides. Between 1934 and 2010, total area of potential nesting habitat decreased by almost 50%. Nesting surveys confirmed that snapping turtles were disproportionately using created nesting mounds and this suggests that availability of natural nesting habitat is limited. We also radio tracked 11 snapping turtles to identify use of overwintering habitat. Temperature loggers monitored in-situ water temperatures at each turtle’s location and other unconfirmed habitats. The snapping turtle population overwintered in a wide range of upland terrestrial habitats and we found consistent characteristics regarding water temperature across both confirmed and unconfirmed sites, therefore suggesting overwintering habitat may not be limiting within the marsh.


Snapping turtle Chelydra serpentina Urban impacts Critical habitat Overwintering Nesting 



All field work was conducted respectful of approved McMaster University animal use protocols (No. 17-01-05) and site-specific permits (Hamilton Conservation Authority land access, Wildlife Scientific Collector’s Authorization No. 1084392 and Royal Botanical Gardens No. 2016-07). Thank you to the students of the Chow-Fraser lab and to Jacqueline Garnett for assisting with data collection. Thanks to Dylan Melmer for his insight and help with analysis. We also like to thank the Hamilton Conservation Authority and Royal Botanical Gardens.


This project was funded by the Natural Sciences and Engineering Research Council of Canada.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of BiologyMcMaster UniversityHamiltonCanada

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