Species and demographic responses to wildlife‐friendly fencing on ungulate crossing success and behavior

Josiane Segar,Aidan Keane

doi:10.1111/csp2.285

Abstract

AbstractFencing is a ubiquitous part of the landscape across the Great Plains of North America. This can fragment habitats and reduce the ability of wildlife to move between patches. A relatively novel conservation tool aimed at mitigating these impacts is the use of wildlife‐friendly fencing. However, there is still an incomplete understanding as to how this tool affects ungulate movement and whether it increases habitat connectivity across barriers. Using camera trap data from three properties across the American Prairie Reserve, Montana, we investigated the effects of fencing on four ungulate species. Averaged across species and demographics, this wildlife‐friendly fencing design increased the probability that ungulates successfully crossed a fence by 33% and reduced the time taken to cross by 54%, but has limited effects on species' crossing behavior. Responses to the wildlife‐friendly fencing differed between species, sex, and age class. The greatest improvement in permeability was detected for mule deer, females, and juvenile groups. Yet, permeability remained lowest for elk, juveniles, and males overall at both fence types. Understanding these differences between groups is important when improving or selecting fence designs, and we highlight vulnerable groups that may require further study when implementing this conservation tool.

Highlights

Habitat fragmentation resulting from human actions is widely considered the greatest threat to the migration and daily movement patterns of global wildlife (Harris, Thirgood, Hopcraft, Cromsigt, & Berger, 2009; Tucker et al, 2018)
When averaged across species and demographics, this wildlifefriendly fencing design increased the probability that ungulates successfully crossed a fence by 33% and reduced the time taken to cross by 54%, but had limited effects on species' crossing behavior
The marginal time taken for a successful fence crossing was 13.3 s, but we found that time taken to cross was highly differentiated by species and demographics

Summary

Introduction

Habitat fragmentation resulting from human actions is widely considered the greatest threat to the migration and daily movement patterns of global wildlife (Harris, Thirgood, Hopcraft, Cromsigt, & Berger, 2009; Tucker et al, 2018). Barriers may have severe long-term ecological consequences, including genetic isolation This may increase rates of inbreeding and mortality, and reduce species' ability to adapt to environmental change (Dodd, Gagnon, Sprague, Boe, & Schweinsburg, 2011). Fencing is a ubiquitous part of the landscape across the prairie ecosystem of the Great Plains of North America (Poor, Jakes, Loucks, & Suitor, 2014), having first been introduced by homesteaders in the 19th century to delineate agricultural and private land (Hayward & Kerley, 2009) Fences in these areas are free-standing structures primarily designed to restrict or prevent movement of livestock across demarcated boundaries; while this can sometimes be beneficial, such as to reduce numbers of animal-vehicle collisions along roads, their structures can negatively affect the movement of wild ungulates (Jakes, Jones, et al, 2018; McCollister & Van Manen, 2010). From a management perspective, unsuccessful wildlife crossings result in damage to the fences themselves and subsequent costs to landowners (Andrews & Rowley, 1998)

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Conclusion