Effects of land-use on Collembola diversity patterns in a Mediterranean landscape

Collembola communities were sampled along a gradient of soil-use intensification in a typical Mediterranen landscape dominated by cork-oak. This gradient ranged from a land-use unit (LUU1) dominated by closed oak forest with minimum intervention to an unit entirely composed of a monoculture crop submitted to frequent anthropogenic disturbances (LUU6), passing through LUUs with managed woodland (LLU2) or dominated by open cork-oak areas and pastures (LUU3 and LUU5). The Collembola community in the overall area was dominated by a few abundant species, mainly Isotomidae, present in almost all units. Abundance, diversity and species richness decreased along the gradient, with the agricultural site presenting an impoverished community. Diversity descriptors were positively and significantly correlated with habitat diversity, measured on the basis of the proportion of the different soil-use types present at each land-use unit. Multivariate analysis revealed changes in Collembola community composition between the LUUs, with LUU6 detaching from the rest. LUU1 and LUU2, despite the less diverse community of the latter, formed a separate group from the remaining two units (LUU3 and LUU5). Species composition in all these units was mainly determined by soil-use types present at each LUU (open cork-oak land and pastures vs. closed cork-oak areas), the proportion of the different soil-use types and the different management practices adopted for each soil use. Overall analysis revealed that Collembola reacted to changes in the landscape structure, with community composition giving a more robust response than diversity indices. (C) 2004 Elsevier GmbH. All rights reserved.