Soil Arthropod Diversity in Organic, Integrated, and Conventional Olive Orchards and Different Agroecological Zones in Crete, Greece

Abstract

Soil arthropods were monitored seasonally for one year, in conventional, organic, and integrated olive orchards, located in hilly and plain agroecological zones. A “functional” group of taxa was defined with respect to provision of biological pest control and nutrient cycling services. Comparisons between a) management systems and b) agroecological zones were performed in terms of total abundance, diversity, and functional subgroup. Ordination techniques were applied with management systems and agroecological zones as explanatory variables. Coleoptera, Formicidae, Araneae, and Collembola were the most abundant taxa. Higher number of total catches, however not statistically significant, appeared in the organic orchards. Diversity did not present a constant pattern or significant differences among management systems. Hilly orchards showed significantly higher seasonal total arthropod diversity and evenness. Abundance of functional arthropods followed a similar trend as total abundance and was seasonally significantly higher in hilly orchards. Agroecological zones and organic management explained the biggest fraction of arthropod variability; however, the total variability explained was rather low. Management systems were the least decisive factors determining arthropod community composition. Less intensive olive production systems appeared to favor soil arthropod diversity.