Virginia opossum distributions are influenced by human-modified landscapes and water availability in tallgrass prairies

Abstract

The Flint Hills represent the largest tract of tallgrass prairie in North America and is located near the western edge of the native range of the Virginia opossum (Didelphis virginiana). This region is undergoing rapid landscape changes (e.g., urbanization, agriculture, woody encroachment) that are negatively affecting mammal communities. Although previous research has revealed northward distributional expansions of Virginia opossums facilitated by urban development, no studies have assessed how landscape change affects distribution patterns along the western edge of their geographic range. During 2016–2018, we monitored site (n = 74) occupancy along urban–rural transects in the Flint Hills to assess the influence of landscape change (i.e., urban, grassland, agriculture, woody encroachment) and water availability on the distribution of Virginia opossums. Sites surrounded by urban land cover had greater initial occupancy probabilities and lower extinction rates. Sites closer to permanent water sources experienced greater colonization rates and lower extinction rates. In addition, site extinction rates were lower in areas surrounded by woody encroachment. Our results concur with other studies suggesting that growing urban areas may expand opossum distributions along the edges of their geographic range. Our study also suggests that woody encroachment into tallgrass prairies may provide an alternative pathway for future distributional expansions. Future research must consider the potential for landscape change, along with dynamic water availability, in models predicting the distribution of Virginia opossums.

Effects of multiple aspects of anthropogenic landscape change on mesopredator relative abundance

“…For instance, the result that skunk relative abundance increased as forest cover decreased may be due both to skunks' attraction to agricultural and other human-dominated landscapes and to a decreased ability to detect skunks in forested areas. However, given that the results of our models for opossum and skunk largely followed predictions from studies that accounted for detection probability (Lesmeister et al 2015;Wait et al 2020;Allen et al 2022b), we believe that our results are still valid. However, we recommend altering spotlight survey designs to account for distance to individuals, incorporate repeat surveys, or integrate time-to-detection (Strebel et al 2021), allowing for true abundance to be estimated instead of relative abundance.…”

“…Skunk and opossum relative abundance were strongly correlated with autumn olive presence at the landscape scale. Landscape-scale probability of autumn olive presence is negatively correlated with latitude and positively correlated with proportion of forest cover; their combination may be the best explanation for opossum relative abundance (Kanda et al 2006;Wait et al 2020). Thus, landscape-scale probability of autumn olive presence is likely in the top model for opossum because it is more information-rich as a covariate than either latitude or proportion of agriculture or forest.…”

“…For instance, skunks are commonly associated with human structures and sometimes with agricultural fields at landscape scales (Gehring and Swihart 2003;Lesmeister et al 2015;Allen et al 2022a). In both urban and rural areas, opossums are associated with forests and water sources at local scales (Gehring and Swihart 2003;Fidino et al 2016;Wait et al 2020). Raccoons prefer forest cover in rural landscapes (Dijak and Thompson 2000;Gehring and Swihart 2003) and often use anthropogenic food sources (Demeny et al 2019).…”

“…Although opossums and raccoons are often associated with urban areas (Fidino et al 2016(Fidino et al , 2020Wait et al 2020), given that the landscape of Illinois is primarily agricultural or forested, we expected that opossum relative abundance would be greater in areas with high proportions of forest cover or water (Gehring and Swihart 2003;Fidino et al 2016;Wait et al 2020) at local scales, and that raccoon relative abundance would be greater in areas with high proportion of forest cover at local scales due to raccoon preferences for forest edges (Dijak and Thompson 2000;Gehring and Swihart 2003). We expected that all three mesopredator species would exhibit a negative response to presence of invasive shrub species, because these species' thick vegetation can leaf out early and obscure detection of animals during spotlight surveys.…”

Spatial and temporal overlap of domestic cats (Felis catus) and native urban wildlife

“…We broadly hypothesized that forested habitat (Bozek et al, 2007;Fidino et al, 2016;Lombardi et al, 2017), water sources (e.g., Fidino et al, 2016;Lombardi et al, 2017;Wait and Ahlers, 2020), human population density (e.g., Luck, 2007;Lombardi et al, 2017), vehicular traffic (e.g., Goodwin and Shriver, 2011;Chen and Koprowski, 2015), and per capita income (e.g., Hope et al, 2003;Clarke et al, 2013; but see also Magle et al, 2021) would influence the probability of presence for each species. We initially considered 23 variables that represented these broader categories and calculated them for each grid cell at each spatial scale (see Supplementary Appendix 1 for a list of variables and methods for calculating each variable).…”