Study species and questions
We studied snake-vegetation relationships in habitats of three species representing the three main phylogenetic lineages of the V. ursinii complex (Freitas et al., 2020). V. graeca (Nilson & Andrén, 1988) is an endangered species endemic to the Pindos mountains in Albania and Greece, inhabiting dry sub-alpine grasslands above the treeline between 1600 and 2200 m above sea level (Mizsei et al., 2018b).V. renardi (Christoph, 1861) is widely distributed in the steppe biome from Ukraine to China, from lowlands to high mountains, and shows high intraspecific genetic diversity (Zinenko et al., 2015). The nominal subspecies V. r. renardi , sometimes referred to as “western” or “lowland” V. renardi (Nilson & Andrén, 2001; Zinenko et al., 2015) was involved in our study. V. ursinii (Bonaparte, 1835) is a vulnerable species endemic to Europe, consisting of three phylogenetically divergent lineages in sub-alpine meadows and two on lowland grasslands (Ferchaud et al., 2012; Mizsei et al., 2017).V. ursinii rakosiensis (Méhely, 1893), also known as the Hungarian meadow viper, an endangered lowland subspecies (Péchy et al., 2015) was involved in our study. In each study system, we addressed the same three questions: (1) Which variables describing vegetation structure explain the occurrence of particular snake species? (2) Are differences between influential vegetation structure variables related to differences in habitat selection between species? (3) Which variables can be recommended for use in studies of snake habitat selection in grasslands?