Ontwikkeling van de bodemdiergemeenschap in de geulen van referentiegebied Rottum : tussenrapportage 14 jaar na sluiting (najaar 2019)

Summary

Since November 2005 a small part of the Dutch Wadden Sea has been closed to bottom-disturbing anthropogenic activities. The area is situated just to the south of Rottumerplaat and Rottumeroog islands and covers about 7,400 hectares. The purpose of closing this area is to monitor the development of the marine fauna in the Wadden Sea when they are not disturbed by human activities. The monitoring programme focuses on the development of the benthic communities present in the gullies. The benthic fauna in two gullies in the closed area are being monitored and compared with the fauna in two control gullies outside the closed area which are under the influence of human bottomdisturbing activities. This report describes the interim results 14 years after the area was closed. Of the investigated gullies, the closed Boschwad gully is the smallest in surface area and has a lower water depth and finer sediment grain sizes than the other gullies. In line with what has been established earlier, the benthic species composition in the Boschwad gully differs from the other gullies by having a slightly higher abundance of shellfish (especially cockles) and a higher abundance and different composition of Annelid species. This might be due to the different physical characteristics of the gully described above. The species composition in the closed area Schild is more similar to that in the two open gullies, possibly as a result of greater natural disturbance (influence of wind and waves on the sediments).