Fine‐scale vegetation complexity and habitat structure influence predation pressure on a declining snake

Abstract

In Western Europe, omnipresent human activities have considerable impacts on habitats at several spatial scales resulting in direct shifts in habitat characteristics. These modifications in habitat features can disrupt biotic interactions such as predation. Surprisingly, although snake species are facing a worldwide decline, relationships between habitat characteristics and predation pressure in snakes remain poorly understood. The main goal of this study was to assess predation pressure on a snake species (the common adder; Vipera berus) in relation to two habitat characteristics: fine‐scale (microhabitat) vegetation complexity and habitat structure (linear/non‐linear). Using 2400 artificial plasticine models of adder as lures in 12 sites in Wallonia (Belgium), we quantified and compared the relative predation risk with respect to these two habitat features. We showed that, all predators combined (mammals and birds), increasing vegetation complexity had a positive impact by decreasing predation pressure, while habitat linearity increased attack risk on adders. However, for mammalian predators, increasing structural complexity reduced predation risk in non‐linear habitats while this risk remained constant and substantial in linear habitats. This suggests that the abiotic benefits of linear strips or edges may be balanced by high predation risks. For bird predators, habitat linearity had no effect on attack rates while an increase in structural complexity reduced attack probabilities. In the light of these results, we suggest applying management practices that ensure a high degree of structural complexity in semi‐natural habitats concerned with snake conservation. Moreover, we recommend creating non‐linear, highly structured habitat elements to hamper predation pressure by mammals.

The red fox (Vulpes vulpes) is the dominant predator of lizard models in a semi‐arid landscape, and predation risk is reduced by vegetation cover

“…Our study corroborates this by demonstrating that foxes were the dominant predator of lizards during the summer months in a semi‐arid region. More generally, our findings are consistent with previous studies of plasticine model reptiles that have found mammals to be dominant predators (Duchesne et al., 2022; Purger et al., 2017).…”

“…(2022) observed that reptiles are more frequently found in the diets of foxes in areas with sparse vegetation and higher temperatures. This finding is complemented by other research underscoring the role of vegetation structure in moderating reptile predation risk (Duchesne et al., 2022; Hansen et al., 2019; Sato et al. 2014).…”