Document of bibliographic reference 106738

BibliographicReference record

Type

Bibliographic resource

Type of document

Book chapters

BibLvlCode

AM

Title

Direct and indirect effects of predation on an intertidal benthic community

Abstract

Intertidal estuarine habitats are extensively used as feeding grounds by birds, fishes and crustaceans. The impact of predation on the intertidal macrobenthic community has been measurable, although not consistently. A macrobenthos monitoring study at various tidal heights on a mudflat in the Scheldt estuary revealed that when fish abundance was high, the density of the main prey species (Corophium volutator) was significantly reduced on the lower and middle shore, but not on the higher shore. On the lower parts of the shore, where the inundation time is longer, fish predation may reduce the density of macrobenthic prey. The effect of predation on the intertidal macrobenthic community was examined by excluding both birds and fishes from the mudflat. A first caging experiment lasted for two months and excluded both birds and fishes, while a second experiment ran for a whole year and excluded only birds. Fish and bird predation did not have a significant direct effect on the abundance of macrobenthic species. Diet analysis showed that both predators select the larger size classes of the macrobenthic species, but only birds were shown to influence the size distribution of their prey. From the exclosure experiments, fish predation turned out to be relatively unimportant as a structuring factor for the macrobenthic prey community. However, fish abundance during the caging experiments was much lower than during the monitoring study. The effects of short-term experiments may only be noticeable at higher predator densities. In the long-term experiment, the density of C. Volutator in the cages was significantly lower than in the uncaged plots. In the absence of predation, infaunal interactions like competition may become more important and regulate the benthic community structure.

Bibliographic citation

Stevens, M.; Cuveliers, E.L.; Maes, J.; Ollevier, F.P. (2006). Direct and indirect effects of predation on an intertidal benthic community, in: Stevens, M. Intertidal and basin-wide habitat use of fishes in the Scheldt estuary = Getij- en bekkengebonden habitatgebruik door vissen in het Schelde-estuarium. pp. 61-80

Topic

Marine

Fresh water