Collected reprints: Abstract 3427

Collected reprints

Abstract

Jocqué, R.; van Damme, D. (1971). Inleidende oecologische studie van klei- en turfbanken in de getijdenzone te Raversijde (België). [Introduction to the ecological study of intertidal clay- and peatbanks at Raversijde (Belgium).]. Biol. Jb. Dodonaea 39: 157-190

The beach of Raversijde shows substrata which are very rich in comparison to the rest of natural substrata along the Belgian coast, consisting exclusively of sandy beaches. At this moment however it is threatened by silting up due to construction of breakwaters. From June to December 1970 samples were taken at several places of the beach. The investigation was focused on the peatbanks situated around mean tide level and the claybanks near low tide level. The foulding of those substrata was compared to that of wooden wreck situated near mean tide level . We found that the foulding on the vertical slopes of peatholes was characterised by as striking periodicity. This is due to the fact that only a few organisms are able to settle down immediately on peat. The most important are the barnacles Eliminius modestus and Balanus crenatus, which we call "pioneers". They allow further colonisation by organisms not able to settle down on peat e.g. Mytilus edulis. When the foulding grows thick and heavy the pioneers are choked and lose hold. Together with them the whole overgrowth disappeared from the vertical slopes by August. It was replaced by Laomedea longissima which stayed the dominating organism until December. As a result of temporary silting up and by lack of recolonisation the overgrowth practically disappeared as a whole during the winter. Periodicity is not so striking on the claybanks near low tide level where Zirfaea crispata and Petricola pholadiformis, both rock borers, allow further colonisation by foulding organisms. An important part of the foulding disappeared together with Mytilus edulis which was choked up by Balanus crenatus. The fouling of the wooden wreck showed little variation during our investigations. It was dominated by B. crenatus, E. modestus, M. edulis, Electra pilosa and Alcyonidium mytili. Two organisms new for the Belgian coast were figured.

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