Spatial and Temporal Variability of Invertebrate Communities in Vernal Pools on the Coastal Plain of Virginia

ABSTRACT The taxonomic composition and abundance of the invertebrate communities and the extent of spatial and temporal variation inherent in those communities was determined among a suite of 10 vernal pools located in close proximity to each other in eastern Virginia, USA. Crustaceans, water mites (Hydracarina) and dipterans composed the majority of the invertebrates in the pools. Taxa occurring in all of the pools were the chironomid Endochironomus sp., a cyclopoid copepod (Cyclops sp.), a species of long-legged fly (Dolichopodidae), and water mites. The majority of taxa, however, occurred in less than half of the pools. Principal components analysis indicated considerable differences in the taxa present and their abundances among pools shortly after the pools were inundated in January. Much less variability in the taxa present and their abundances among the pools occurred prior to the pools drying in April-May, indicating a convergence in community structure in the closely located but hydrologically distinct pools. Taxa richness and abundance in the pools both decreased as the hydrologic year progressed.