Differences in mammal community response to highway construction across different levels of human land use

Worldwide, transportation agencies have been involved in road mitigation efforts to reduce road mortality and promote connectivity of endangered species. Baseline data on how mammals respond to highway construction, however, is rarely collected in road mitigation and monitoring studies, including in the United States. Our goal in this study was to assess differences in the response of the mammal community to highway construction along a gradient of human land use (HLU) from July 2019 to November 2020 in southern Texas, United States. We compared the species composition of the terrestrial mammal community at five sites along a highway before and during highway construction and assessed diel activity for seven species at different HLU levels between these two time periods. We found that mammal community composition was lower during the construction period at each HLU level. There were greater differences in the composition of the mammal community in the pre-construction and construction periods as HLU decreased. Community diversity was greatest in areas with a low level of HLU, followed by areas of medium and high levels, with more carnivores, large ungulates, and rodents at medium and low HLU sites. For many species, diel activity patterns across all sites during the construction period reflected activity patterns in areas of higher HLU during the pre-construction period. Our study shows that community composition and behavior (diel activity) are likely to change in response to highway construction regardless of the degree of HLU. These results may influence how scientists and transportation agencies consider potential impacts on wildlife species during road construction and affect their attempt to mitigate these impacts.

Methods
Camera trapping; R; Primer