Fine-scale biogeographic differences in the crustacean fauna of a cave system in West Virginia,USA

We examined the distribution patterns of four amphipod and one isopod crustaceans in 23 cave stream segments within a subterranean drainage basin. The patterns indicate that invasion history is a strong determinant of the species' distributions. One set of species likely has invaded the cave system from the zone of interstitial water, and thus is distributed mainly in headwater streams throughout the drainage. One species probably invaded through upstream migration from the resurgence of the cave system, and thus is strongly associated with the larger, higher-order streams. The effect of interspecific interactions on the patterns of distribution is not apparent at our scale of analysis.