Diversity of spiders in an almond Prunus dulcis (Mill.) D.A. Webb orchard in the Metropolitan Region of Chile (Central Chile)
The species of epigeal Araneae from an almond orchard located in the former El Mariscal Ranch (33036'30.5"S-70038'30.3"W) in the Metropolitan Region, Chile were investigated. The samples were taken using pitfall traps placed in two parallel transects, one within the orchard and the other in the adjacent uncultivated border, each with 5 traps. The sampling period extended from September to December 2006 and September to December 2007. The collected material was removed approximately every 15 days. The determination of families was made through taxonomic keys (Ramírez, 1999; Aguilera & Casanueva, 2005); the species were distinguished only by morphological differences. The total number of spiders collected was 2556, including 11 families and 37 species. The most abundant families, in decreasing order, were Linyphiidae, Gnaphosidae, Dysderidae and Anyphaenidae, which together included 72% of the total. Linyphiidae was the most abundant family during the two sampling periods. The families Anyphaenidae, Linyphiidae, Dyctinidae, Gnaphosidae and Salticidae accounted for 70% of the total species richness. Wandering spiders were dominant in the almond orchard, probably related to the disturbances due to agricultural practices. On the other hand, the uncultivated border showed a dominance of web-building spiders, probably due to the greater stability and complexity of the habitat.