Evaluating predator diversity and abundance in vineyards and the contiguous hedgerows

The presence of uncultivated areas in agro-ecosystems may affect crop arthropod populations. A diversity index can be a useful tool for comparing farms with varying amounts of uncultivated land and evaluating the role of different cropping systems. The aim of this study was to evaluate the abundance and diversity of predator arthropods in hedgerows and vineyards located in organic or conventional farms, utilising the classic concise indices of population structure/composition and the Quadratic Diversity (Q) Index, which is innovative but more complicated to calculate. Investigations carried out in north-eastern Italy stressed that hedgerows were populated by a higher number of predatory species than nearby vineyards. Moreover, there was a higher species richness in vineyards adjacent to hedgerows than in those farther away, independently of the type of management. If there are no objective criteria for defining dissimilarities between species, the Q index provides the same information as other indices of diversity (i.e. Shannon or Pielou).