Study

Species loss and shifting population structure of freshwater turtles despite habitat protection

  • Published source details Browne C.L. & Hecnar S.J. (2007) Species loss and shifting population structure of freshwater turtles despite habitat protection. Biological Conservation, 138, 421-429.

Actions

This study is summarised as evidence for the following.

Action Category

Protect habitat: All reptiles (excluding sea turtles)

Action Link
Reptile Conservation
  1. Protect habitat: All reptiles (excluding sea turtles)

    A replicated, before-and-after study in 1972–1973 and 2001–2002 in forest and wetlands in Ontario, Canada (Browne & Hecnar 2007) found that decades of habitat protection had mixed effects on capture rates of native species and one introduced species was newly recorded. Results were not statistically tested. Thirty years after a first survey, capture rates tended to be higher for northern map Graptemys geographica (2002–2003: 0.004 individuals/hoop net night vs. 1972: 0.002) and stinkpot Sternotherus odoratus turtles (0.005 vs. 0.004). However, captures tended to be lower in 2002–2003 for painted Chrysemys picta (0.143 vs. 0.192), Blanding’s Emydoidea blandingii (0.01 vs. 0.054), snapping turtles Chelydra serpentina (0.1 vs. 0.174) and spotted turtles Clemmys guttata (0 vs. 1 individual). Two spiny softshell Apalone spinifera and three introduced pond slider turtles Trachemys scripta were observed for the first time in 2002–2003. Turtle abundances were monitored in a 16 km2 heavily trafficked National Park (gazetted in 1918, designated a Ramsar site in 1987, up to 500,000 visitors/year) in 1972–1973 and 2002–2003 using similar methods. Turtles were trapped using hoop (2002–2003: 3,237 hoop net trap nights; 1972: 522), basking and wire cage live traps as well as hand captures for two months in spring each year. In 2001–2002, all turtles were weighed, measured, sexed, and individually marked before release. Reported catch/trap nights above are for hoop net captures only.

    (Summarised by: Maggie Watson)

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