Crustacean Biodiversity and Endemism in California’s Ephemeral Wetlands

While knowledge of the fauna of California’s ephemeral wetlands has lagged behind that of the flora, recent work has revealed extraordinarily diverse and highly endemic communities. Two recent surveys of crustaceans have shown a number of important attributes of these systems. 1) Species richness and species composition differ among habitat types. 2) Not all pools in an area contain all the same species. 3) Some species are widespread while others are found rarely. 4) Many species are undescribed and little is known of their requirements. 5) Large ephemeral lakes are richer than many permanent lakes. 6) Some populations of restricted species have low genetic variability. 7) The co-occurrence of congeners is common. Several factors may be involved in producing this unexpected richness, including high primary productivity, reduced predation, and habitat heterogeneity. However, while some of these factors apply to some pools, they are not sufficient to explain the richness of all pool types. Those factors which do apply to all pools and are potentially the most interesting are produced by the effects of the ephemerality and unpredictability of the system on life history evolution. These attributes of California’s ephemeral wetlands, along with their rapid loss, have numerous implications for the conservation of biodiversity in these systems. CITATION: Pages 107-118 in: C.W. Witham, E.T. Bauder, D. Belk, W.R. Ferren Jr., and R. Ornduff (Editors). Ecology, Conservation, and Management of Vernal Pool Ecosystems – Proceedings from a 1996 Conference. California Native Plant Society, Sacramento, CA. 1998.