Impact of agricultural management on spider populations in the canopy of olive trees

In the province of Granada (southern Spain) spiders were studied in olive-tree canopies, in olive orchards under similar environmental conditions but different management systems: organic, integrated and conventional. Monthly samplings (March to October) was performed in the canopy by the beating method. Spider abundance proved significantly higher in the organic than in the conventional orchard. An intermediate disturbance level in the integrated regime increased spider diversity, while the conventional management favoured higher dominance of the family Oxyopidae. Four families (Thomisidae, Oxyopidae, Salticidae, and Theridiidae) comprised more than 83% of the specimens captured, of which Thomisidae and Salticidae declined in abundance between organic and conventional management, whereas the family Oxyopidae was favoured as management disturbance increased.