Long-term human-induced landscape changes and small mammal communities in a Mediterranean place

Abstract

The small mammal community (Orders Rodentia and Eulipotyphla) was evaluated in one single locality in coastal Catalonia in relation to human-induced changes in land use. Low detectability of some species drove us to assess the small mammal assemblages analysing barn owl (Tyto alba) pellets sampled in the same nesting site for a period of thirty years. The objectives were to 1) describe variations in landscape use, 2) document small mammal community changes and 3) relate these changes to those in land use. Species richness did not seem to vary with changes in land use, however, when species were separated into guilds (open, forest and synanthropic), significant differences could be observed. The open guild decreased by 6%, while the forest and synanthropic guild increased by 5% and 2% respectively. Abandonment of arable land, expansion of forested areas and an increase in urbanisation were closely linked to these guild changes, while some individual species showed variations which paralleled climatic changes. Loss of adequate open habitat for this raptor was highlighted by a species substitution, with the tawny owl (Strix aluco) occupying the nesting site previously used by the barn owl during the last years of the study. Barn owl diet monitoring therefore proves to be a useful tool to analyse small mammal community responses to changes in the environment, allowing for more specific and viable conservation plans for both small mammals and barn owls.