Study

Reproductive ecology of Graptemys geographica of the Juniata River in central Pennsylvania, with recommendations for conservation

  • Published source details Nagle R.D. & Congdon J.D. (2016) Reproductive ecology of Graptemys geographica of the Juniata River in central Pennsylvania, with recommendations for conservation. Herpetological Conservation and Biology, 11, 232-243.

Actions

This study is summarised as evidence for the following.

Action Category

Manually remove reptiles from roads

Action Link
Reptile Conservation

Install barriers along roads/railways

Action Link
Reptile Conservation

Create artificial nests or nesting sites

Action Link
Reptile Conservation
  1. Manually remove reptiles from roads

    A study in 1999–2008 on a roadside verge along a river bank in Pennsylvania, USA (Nagle & Congdon 2016) found that when turtles were actively moved off a road after a chain-link fence was installed along a highway and artificial nest mounds were created on the non-road side of the fence, fewer female northern map turtles Graptemys geographica were killed on the road compared to before any interventions began. Results were not statistically tested. In the 2nd to 8th year after a fence was installed on a new major highway, when turtles were being actively removed from the road, 0–5 map turtles died on the road/year (no data for other species). In the first year after a fence was installed, 10 northern map turtles were killed on the road, and in the years before installation 50 turtles were killed on the road (total included a small number of wood turtles Glyptemus insculpta and snapping turtles Chelydra serpentina).  The authors reported that most deaths were gravid female turtles. In 2000, a fence (1 m high and 1,150 m long) was installed on the river side of the highway to prevent turtles from crossing the road to access nesting habitat. Mounds of sand aimed at providing alternative nesting habitat were added to the river side of the fence in 2000–2001. After the first year, the fence was extended by 300 m to prevent turtles from going around it and crushed shale was added to the sand mounds and turtles were actively moved off the road. Turtle deaths on the road were counted from 1999 (the first year after a new highway opened) to 2008 (excluding 2004).

    (Summarised by: Katie Sainsbury)

  2. Install barriers along roads/railways

    A before-and-after study in 1999–2008 on a roadside verge along a river bank in Pennsylvania, USA (Nagle & Congdon 2016) found that after adding a chain-link fence to a highway, creating artificial nest mounds on the non-road side of the fence, and actively moving turtles off the road, fewer female northern map turtles Graptemys geographica were killed on the road. Results were not statistically tested. In the first year after a fence was installed on a new major highway, 10 northern map turtles were killed on the road, compared to 50 turtles the year before (total for previous year included a small number of wood turtles Glyptemus insculpta and snapping turtles Chelydra serpentina).  In the subsequent 8 years, map turtle deaths reduced to 0–5 individuals/year (no data for other species). The authors reported that most deaths were gravid female turtles. In 2000, a fence (1 m high and 1,150 m long) was installed on the river side of the highway to prevent turtles from crossing the road to access nesting habitat. Mounds of sand aimed at providing alternative nesting habitat were added to the river side of the fence in 2000–2001. After the first year, the fence was extended by 300 m to prevent turtles from going around it and crushed shale was added to the sand mounds and turtles were actively moved off the road. Turtle deaths on the road were counted from 1999 (the first year after a new highway opened) to 2008 (excluding 2004).

    (Summarised by: Katie Sainsbury)

  3. Create artificial nests or nesting sites

    A study in 2000–2008 on a roadside verge along a river bank in Pennsylvania, USA (Nagle & Congdon 2016) found that sand and shale mounds built along a barrier fence as mitigation nesting habitat after a road was constructed were used by a small number of nesting female northern map turtles Graptemys geographica in the first year. In the first year following creation of sandy mounds as nesting sites, two of 50 nests were laid in the sand mounds. The authors reported that most females walked over the sand mounds and nested near the barrier fence. In 1999, a new highway was built along a major river and in 2000 a chain-link fence (1 m high, 1,150 m long) was erected to mitigate road deaths of female turtles crossing the road to find suitable nesting habitat. Eight mounds of sand (800 m3 total volume) were created on the river side of the road fence to provide nesting habitat. In 2001, the sand was moved closer to the fence and shale was added to reduce vegetation. Turtle nesting was monitored in May–July 2000–2003, 2005–2007 and 2008 (dates not provided for 2008) in the mitigation nesting habitat and at another commonly used nesting site, but data on use of mitigation nesting sites were only provided for 2000.

    (Summarised by: Katie Sainsbury)

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