The free-living nematodes of a temperate, high energy, sandy beach: Faunal composition and variation over space and time

Free-living marine nematodes were sampled extensively over a 2-year period on a long sandy beach exposed to high-energy ocean swells in southeastern Australia. Samples were taken in summer and winter at different tide levels on the beach, and at different positions along the beach. A total of 58 species from 48 genera were found, many as yet known only from Australia. Predators and particle feeders were always the most abundant feeding guilds, but species composition varied markedly between samples. The variation in abundance and composition of the fauna was analysed statistically. There were considerable differences between high-, mid- and low-tide faunas along a single transect of the beach which persisted for 24 h with calm seas, but not over several months. There were also considerable differences between locations along the beach. It appears that hydrodynamic forces constantly redistribute the fauna, introducing a large probabilistic element into patterns of total nematode abundance and faunal composition.