The influence of structural characteristics and environmental factors on the use of wildlife crossing structures

Anna D Rivera Roy, School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley
T. Miles Hopkins, School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX 78578, USA
Thomas J. Yamashita, School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX 78578, USA
Kevin W. Ryer, School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX 78578, USA
John Young, Jr., Environmental Affairs Division, Texas Department of Transportation, Austin, TX 78701, USA
Richard J. Kline, School of Earth, Environmental, and Marine Sciences, University of Texas Rio Grande Valley, Port Isabel, TX 78578, USA
Topic Area
Terrestrial Wildlife and Ecosystem Interactions with Transportation

Roads have long been known to influence wildlife movements and survival. They can have detrimental effects on populations and in time, biodiversity. To facilitate movement and prevent vehicle-caused mortalities, mitigation structures, such as fencing and wildlife crossing structures (WCS), including underpasses, have been developed. Structural characteristics and environmental variables are important factors to include when comparing crossing structure effectiveness. Along State Highway 100 in Cameron County, Texas, 11.9 km of exclusionary fencing and five WCS have been constructed or modified to mitigate wildlife road mortalities. To understand the effectiveness of these WCS, camera trap arrays were placed at the openings to monitor wildlife use. Preliminary analyses with PERMANOVA have shown that communities using the WCS are distinct between each location. We examined differences in species use of WCS in relation to openness ratio, presence of water, precipitation, and distance to nearest native vegetative cover. This research will aid in informing optimal placement and design of future mitigation structures.

Abstract Keywords
wildlife crossing structure
road mitigation
South Texas