Influence of different olive grove management on spider diversity

Spiders are known as one of the most important group of predators in olive agroecosystems, limiting the populations of insect pests and the damage they can cause. However, some agricultural practices are known to modify spider communities changing their species composition and abundance. To assess the influence of different management systems we collected data on spider fauna in three different olive groves and with three different methods. For the three sampling methods biodiversity indexes as Simpson's, Shannon's and Sørensen's were calculated in terms of spiders' families, in order to evaluate their temporal evolution and the relation to crop management systems. This purpose is accomplished in the context of generalized linear models and cluster analysis of dissimilarity matrices.