Predator exclusion experiments in an intertidal mud flat

摘要: The intensity of predation pressure exerted on the macrofauna in muddy sediments was investigated Konigshafen (island Sylt, eastern North Sea). Tests aquaria revealed shrimpCrangon crangon, juveniles shore crabCarcinus maenas, and gobiid fishPomatoschistus microps as most important local predators. Their high abundance from July to September led hypothesis, that infauna will be intense during period. Cages were set up protect against these No protective effect achieved with cages constructed 20-mm mesh nylon net; however, screen wire gauze 5-mm smaller resulted a considerable increase infauna. In 1-mm gauze, March June, reached an four times control density. period October, factor 23. Species density 28 400 cm−2, compared only 7 control. which colonized mud flat spring early summer established dense settlements inside cages, but failed do so uncaged mud-flat areas. It is concluded by young crabs, shrimp gobies determines large extent structure dynamics intertidal macrofauna.