Seasonal changes in spider diversity in subtropical riparian forests: what drives the seasonality of the araneofauna?

Spiders are usually found through all seasons in the subtropics, but little is known about their seasonality patterns and how they respond to abiotic factors, especially in species-rich regions such as Brazil. We investigated the seasonal variation in spider communities and the possible influence of abiotic factors (e.g., temperature, rainfall) on spider abundance, species richness and composition in subtropical riparian forest in four river basins. Changes in spider abundance among seasons differed between ontogenetic stages: there were more spiderlings in the autumn, and similar numbers of adults year round. Species richness, on the other hand, was highest in spring and summer. Species composition differed between seasons and river basins. Several factors may be behind diversity changes in the araneofauna among seasons, however, none of the abiotic factors evaluated showed a strong direct influence. Seasonal patterns varied, with different species having peaks in all three seasons but autumn. Seasonality is clear in these spider communities but not all patterns follow predictions from simple temperature changes.

Automated summary

The study investigated seasonal variation in spider communities in subtropical riparian forest in Brazil. It found that spider abundance differed between seasons and ontogenetic stages, with more spiderlings in autumn and similar numbers of adults year-round. Species richness was highest in spring and summer. Abiotic factors did not show a strong direct influence on spider diversity changes.