Hierarchical habitat-use by an endangered steppe bird in fragmented landscapes is associated with large connected patches and high food availability.

ABSTRACT

Multidimensional approaches must be employed when addressing habitat use patterns. In this study, we aim to elucidate the hierarchical nature of space use by species inhabiting fragmented landscapes, using the threatened Dupont's lark (Chersophilus duponti). The intensity of space use by Dupont's lark was estimated using the Kernel Density Function on territory locations in 2015. We measured descriptors of habitat quality at metapopulation (connectivity and patch size), landscape (land-use types and anthropogenic disturbance) and microhabitat-scale (plant structure and composition, herbivore abundance and food availability) at 37 sampling stations. We fitted a Partial Least Squares Regression (PLSR) which yielded two components, accounting for 81% of total variance. Metapopulation-scale factors had the greatest explanatory power (32%), followed by microhabitat (17%) landscape (10%) and spatial predictors (3.6%). Connectivity and patch size were key factors explaining habitat use, and wind farms had a negative effect. At microhabitat-scale, space use was positively associated with Coleoptera, Orthoptera, Araneae and Diptera biomass, but negatively with Formicidae and Blattodea biomass, the cover of Stipa spp, Koeleria vallesiana and moss. This research highlights the hierarchical nature of habitat use in fragmented landscapes. Therefore, conservation measures should ensure connectivity, guarantee a minimum patch size, and improve habitat quality within patches.