Disentangling the effects of habitat loss and fragmentation on a highly diverse European wildlife.

Habitat loss and fragmentation are among the main threats to global biodiversity and ecosystem services. While the effects of habitat loss on fauna are mostly negative, the responses of animals to fragmentation are varied. The frequency of negative impacts of both processes ultimately depends on taxonomic and functional diversity, the different landscape metrics, and the biological responses considered (e.g. species assemblage, behaviour, genetics). A systematic literature review was conducted to evaluate the impacts of habitat loss, fragmentation and associated landscape metrics on the terrestrial fauna of peninsular Spain, a biodiversity hotspot in Europe. Our database included 107 articles and 1942 cases of the effects (positive, negative or neutral) of habitat loss, fragmentation or a given landscape metric on a biological response in four taxa of vertebrates (amphibians, reptiles, birds and mammals) and six of invertebrates (tardigrades, annelids, springtails, insects, myriapods and arachnids). Habitat loss mostly showed negative impacts, whereas the effects of fragmentation were diverse. Patch size reduction was the most detrimental landscape metric, while matrix contrast and edge effect reduced negative impacts and/or increased positive effects. Relative to the biological responses, richness showed a significantly higher proportion of negative effects, in contrast to positive interactions and behaviour. Vertebrates were more negatively affected than invertebrates by both habitat loss and fragmentation, although matrix contrast caused more negative effects on invertebrates. Behaviour also showed an increase in negative impacts and a decrease in positive impacts in invertebrates compared to vertebrates. The results highlight the dependence on ecological and taxonomic context of the impacts of habitat loss and fragmentation on animal communities. Comparative approaches are required to improve our understanding of the effects of these processes, enabling well-supported conservation actions. Under the challenging scenario of global change and biodiversity crisis, our findings may stimulate similar analyses in different regions of the globe.