Land‐use intensity influences European tetrapod food webs

Abstract

Land use intensification favours particular trophic groups which can induce architectural changes in food webs. These changes can impact ecosystem functions, services, stability and resilience. However, the imprint of land management intensity on food‐web architecture has rarely been characterized across large spatial extent and various land uses. We investigated the influence of land management intensity on six facets of food‐web architecture, namely apex and basal species proportions, connectance, omnivory, trophic chain lengths and compartmentalization, for 67,051 European terrestrial vertebrate communities. We also assessed the dependency of this influence of intensification on land use and climate. In addition to more commonly considered climatic factors, the architecture of food webs was notably influenced by land use and management intensity. Intensification tended to strongly lower the proportion of apex predators consistently across contexts. In general, intensification also tended to lower proportions of basal species, favoured mesopredators, decreased food webs compartmentalization whereas it increased their connectance. However, the response of food webs to intensification was different for some contexts. Intensification sharply decreased connectance in Mediterranean and Alpine settlements, and it increased basal tetrapod proportions and compartmentalization in Mediterranean forest and Atlantic croplands. Besides, intensive urbanization especially favoured longer trophic chains and lower omnivory. By favouring mesopredators in most contexts, intensification could undermine basal tetrapods, the cascading effects of which need to be assessed. Our results support the importance of protecting top predators where possible and raise questions about the long‐term stability of food webs in the face of human‐induced pressures.

Spatially explicit predictions of food web structure from regional-level data

“…It gives us an idea of what local metawebs or networks could look like in space, given species distributions and their variability, as well as the uncertainty around species interactions. We also provide, to our knowledge, the first spatial representation of the metaweb of Canadian mammals [14] and a probabilistic equivalent to how the European tetrapod metaweb [13] was used to predict localized networks in Europe [22][23][24][25]65]. Therefore, our approach could open similar possibilities of investigations on the variation of structure in space [22] and on the effect of land-use intensification [65] on North American food webs, particularly Canadian mammal food webs.…”

“…We also provide, to our knowledge, the first spatial representation of the metaweb of Canadian mammals [14] and a probabilistic equivalent to how the European tetrapod metaweb [13] was used to predict localized networks in Europe [22][23][24][25]65]. Therefore, our approach could open similar possibilities of investigations on the variation of structure in space [22] and on the effect of land-use intensification [65] on North American food webs, particularly Canadian mammal food webs. Other interesting research applications include assessing climate change impacts on network structure (e.g.…”