Separation strategies for invertebrate dormant stages contained in sediment

Invertebrates and their dormant stages are an essential component of most freshwater and marine ecosystems (Cáceres 1997). As the active invertebrate community has a very variable distribution, both in time and space (Arnott et al. 1999, Folt & Burns 1999), reliable assessment of community diversity consequently requires repeated sampling across multiple locations for a prolonged period of time. Various invertebrate taxa produce dormant stages such as dormant eggs (also called diapausing eggs or resting eggs), cysts, or statoblasts that often sink and accumulate in sediments, forming ‘egg banks’ (Brendonck & De Meester 2003). Dormant stages provide a mechanism for invertebrates to endure inhospitable environments and to undertake natural long-distance dispersal (Cáceres 1997). Sediment egg banks integrate spatial, seasonal and annual variation in the abundance and distribution of invertebrates (Brendonck & De Meester 2003, Jeppesen et al. 2003). To accurately assess community composition for purposes of taxonomy, ecological biogeography, paleolimnology, nature conservation, and evolutionary, community, population and invasion ecology, both active and dor mant stages of taxa should be considered (Brendonck & De Meester 2003). FEATURE ARTICLE