Landscape heterogeneity effects on keystone rodent species: agro-ecological zoning for conservation of open grasslands

Grasslands are one of the most threatened ecosystems in the world. Spatial prioritization of high quality habitat in agricultural landscapes is needed to protect grassland biodiversity. Within this context, we focused on European ground squirrel, a keystone species in steppe and salt steppe ecosystems. Using historical data and habitat field mapping, this study evaluates species distribution and site occupancy along the southern margin of the species range (Serbia) and identifies priority conservation zones in an intensively used landscape. Using gap analysis to evaluate changes in distribution over time and land protection status of the occupied area, we found that the regional species range has been constricted by 70%, and that 43% of mapped areas were outside of conservation networks. We also used a landscape structure model and multivariate analysis to identify the effects of spatial heterogeneity on occupancy. After mapping potential conservation zones with a buffer radius of 4.6 km—the scale with significant effects on occupancy—we identified 19 potential agro-ecological zones that cover the full range of mapped species habitats. The proposed agro-ecological zones differ in percentage of occupancy, which was found to increase with the overall landscape heterogeneity. This study contributes to the ongoing effort to broaden the understanding of the ecology and conservation of the European ground squirrel and the grasslands they rely on. Conservation planning should be designed to protect grasslands occupied by ground squirrels, ensure that the agricultural matrix is permeable, and to sustain or enhance landscape heterogeneity.