Road mortality mitigation study...

Animex vs. Mesh

It is important to understand the impact from human development and infrastructure, such as roads in wildlife populations. Road-kill could be contributing to the global amphibian and reptile decline. To reduce this, many types of exclusion structures exist; fencing is the most efficient mitigation measure, however little research is known about what fencing types work best to exclude herpetofauna from roads and there are a lot of concerns with the safety and effectiveness of mesh fencing. Hence, this research tries to fill that gap of knowledge and evaluate the effectiveness of mesh fencing and solid hard plastic Animex fencing and its application for conservation of the herpetofauna.

This behavioral information is then interpreted to evaluate effectiveness of exclusion fencing types for amphibians and reptiles. The animals studied were:

Turtles: 7 Midland painted turtles, MPTU (Chrysemys picta), 7 Snapping turtles, SNTU (Chelydra serpentina). 

Snakes: 16 Eastern gartersnakes, EAGA (Thamnophis sirtalis), 1 Red-belly snake RBSN (Storeria occipitomaculata). 

Frogs: 18 Green frogs, GRFR (Lithobates clamitans), 2 Northern leopard frogs, NLFR (Lithobates pipiens). 

Carlos-Milburn-Animex-Wildlife-Fencing.p

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Methodology

  • The study area was at a private property in Orillia, Ontario also known as Scales Nature Park.
  • Each trial period (1 hour) was comprised of placing an individual animal in an enclosed 25m2 (256ft) area with two sides composed of mesh fencing (1/4 inch), and two sides composed of Animex fencing. 
  • The behaviour, location and interaction of each individual with the two fence types was continuously monitored and recorded. Weather, average air and ground temperatures for each trial period was also recorded.
  • The fenced zone was defined as an animal being within 40cm away from either type of fencing. 
  • Excel was used to analyse the data and calculate the following behavioural responses for each fence type:      
  • The percentage of time an animal spent with the mesh fence zone relative to total time outside of both fence zones      
  • Number of interactions with fence: stopping, poking, clawing etc
  • Number of breaches and climbing attempts

Amphibians, and followed in some places by reptiles, are the animal groups most frequently killed on roads... (Glista et al., 2007; Huijser et al., 2009; Colino-Rabanal & Lizana, 2012).

Discussion & Conclusion

This study summarized and interpreted the behavioural responses of amphibian and reptile groups when interacting with 2 different types of commonly used exclusion and drift fencing: steel mesh and solid plastic (Animex). This study shows that herpetofauna spent more time at or interacting with the mesh fencing than with Animex.

This study shows that herpetofauna spent more time at or interacting with the mesh fencing than with Animex. This study concurs with Kruidering et al., (2005) and Clevenger & Huijser, (2011), about using plastic solid barrier fence as a road mitigation measure for the species studied, as the goal of exclusion fencing is not only to keep animals off the road and from harm, but also to funnel animals safely to wildlife crossing structures; thus mesh fencing is not as effective as Animex fencing in doing this. Herpetofauna will not be directed as easily towards the wildlife crossings with the mesh fence due to additional risk of injury, or escape, and delay. Hence, if herpetofauna takes longer to reach wildlife crossing it could increase the potential risks from roads such as, pollution, vibration, noise, illegal collection, persecution, and desiccation/dehydration due to the microclimate and the change of habitat close to the road (Ferronato et al. 2014; Kimberley et al., 2015).  

References

1 . Animex Fencing. 2016. . Last accessed: 03/July/2016

2.  Colino-Rabanal V.J. and Lizana M. 2012. Herpetofauna and roads: a review. Basic and Applied Herpetology, 26: 5-31

3.  Glista D.J., DeVault T.L. and DeWoody J.A. 2007. Vertebrate road mortality predominantly impacts amphibians. Herpetological Conservation and Biology 3(1):77-87pp.4

4.  Aresco M.J. 2005. Mitigation measures to reduce highway mortality of turtles and other herpetofauna at a North Florida lake.  Journal of Wildlife Management 69(2):549-560pp.

5.  Crosswhite D.L., Fox S.F. and Thill R.E. 1999. Comparison of Methods for Monitoring Reptiles and Amphibians in Upland Forests of the Ouachita Mountains. Okla. Acad. Sci. 79:45-50pp.

6.  Kruidering, A.M., G. Veenbaas, R. Kleijberg, G.Koot, Y. Rosloot, and E. van Jaarsveld. 2005. Leidraad faunavoorzieningen bij wegen. Rijkswaterstaat, Dienst Weg-en Waterbouwkunde, Delft,       The Netherland   

7.  Clevenger, A.P. & M.P. Huijser. 2011. Wildlife Crossing Structure Handbook Design and Evaluation in North America. Department of Transportation, Federal Highway Administration,       Washington D.C., USA. Available from the internet:

8.  Huijser, M. P., J. W. Duffield, A. P. Clevenger, R. J. Ament, and P. T. McGowen. 2009. Cost–benefit analyses of mitigation measures aimed at reducing collisions with large ungulates in the      United States and Canada; a decision support tool. Ecology and Society 14(2): 15pp