Manually remove reptiles from roads

Overall effectiveness category Awaiting assessment
Number of studies: 1
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Calculating overall effectiveness category

Background information and definitions

Many reptiles are killed by vehicles, particularly when crossing roads when moving to and from breeding habitats. In some areas, local volunteers may try to reduce deaths by collecting reptiles and releasing them on the other side of the road.

Ideally evidence of the effectiveness of this intervention would consist of survival rates, counts of animals in the population or numbers killed on the road before and after or at sites with and without human assistance. However, such evidence is rarely available.

For other interventions that involve engaging volunteers to help manage reptiles or their habitats see Education and awareness raising – Engage local communities in conservation activities.

Study locations

Key messages

One study evaluated the effect on reptile populations of manually removing reptiles from roads. This study was in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Survival (1 study): One study in the USA reported that when turtles were being removed from a road following installation of a fence and artificial nesting mounds, fewer turtles were killed on the road than in the year before any interventions began.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

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 2^nd to 8^th 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).
Study and other actions tested
Referenced paper
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.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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This Action forms part of the Action Synopsis:

Reptile Conservation

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