Spider Assemblages in Costa Rican Cloud Forests: Effects of Forest Level and Forest Age

Abstract

We investigated spider assemblages in trees at three cloud forest sites and in trees isolated in pasture habitat in Monteverde, Costa Rica. Spiders were collected from two forest types (primary and secondary) within each forest site, and at two different levels (canopy and understory) within forest types and the pasture. They were identified to family or genus level and assigned to morphospecies. Araneidae and Linyphiidae were the most commonly collected families at all locations. Although spider abundance and morphospecies richness did not differ between forest types, perhaps due to their close proximity, these parameters were generally lower in the forest canopy than in the understory. Relative abundances of nearly all common spider families also differed between canopy and understory levels within forests, suggesting that distinct sub-assemblages exist. However, spider abundance and morphospecies richness did not differ between canopy and understory in pasture trees. Spiders were generally more abundant and more diverse in the pasture than the forest, possibly due to its lower elevation or its greater habitat complexity in the form of vascular epiphytes.