Seasonal Patterns in a Tropical Lowland Forest

Abstract

To identify and describe the seasonal patterns of foliage phenology and arthropod abundance in a regenerating lowland wet forest of Costa Rica, monthly samples were taken for one year. Three arthropod sampling methods were used: sweep samples, gleaning of live plant material, and the collection and chloroforming of dead suspended leaves. A major flush of new leaves occurred at the beginning of the wet season, and a minor one towards the end of the wet season. Leaf fall and litter were greatest in the short dry season. Arthropod abundance was lowest in the middle of the wet season, probably due to the scarcity of new leaves then and to the direct physical effects of torrential rains. Seasonal patterns of arthropod abundance varied among taxa, and among sampling methods. In particular, the arthropod fauna of dead, suspended leaves showed little seasonality.