No abstract

During the Bremerhaven Workshop, the meiofaunal communities along 2 supposed North Sea pollution gradients, one at a drilling site off the Dutch coast and the other across the German Bight, were analysed by a variety of univariate and multivariate techniques and the changes on community structure related to a suite of measured environmental variables. At the dnlllng slte the only evidence of change in community structure was a slight reduction In the abundance of nematodes in the deeper parts of the sediment (2 to 10 cm) close to the drilling slte. Otherwise, there were no significant differences between sites using any other measure of community structure. It is concluded that suffic~ent tlme had elapsed since the cessation of drilling activity for a complete recovery of the copepod communities. Any differences which may still have been detectable in the nematode communities had been confounded by the scale of sediment disturbance caused by recent storms. Significant differences were found in the meiofauna communities along the German Bight transect but these are mainly correlated with corresponding changes in sediment granulometry and water depth. Although the addition of zlnc unproved the correlation between environmental variables and copepod community structure, it is argued that heavy metal contamination on thls gradient is not likely to influence meiofaunal communities because (1) there is llttle variation in concentrations and (2) these concentrations are not particularly high when compared to other unpolluted (and polluted) areas of the North Sea.

A large-scale database concerning benthic copepods from the Arctic, Baltic Sea, North Sea, British Isles, Adriatic Sea and Crete was compiled to assess species richness, biodiversity, communities, ecological range size and biogeographical patterns. The Adriatic showed the highest evenness and the most species-rich communities. Assemblages from the North Sea, British Isles, Baltic and Crete had a lower evenness. The British Isles were characterised by impoverished communities. The ecological specificity of copepod species showed two diverging trends: higher specificity of species in more diverse assemblages was observed in the Adriatic, North Sea and Baltic. A uniformly high species specificity disregarding sample diversity was found on Crete and in the British Isles. Benthic copepod communities showed distinct 123Mar Biol DOI 10.1007/s00227-010-1454 patterns that clearly fit the predefined geographical regions. Communities were distinguishable and b-diversity was found to be high around Europe, indicating a high species turnover on the scale of this investigation. The British Isles and the North Sea were found to be faunistic links to the Baltic and the Arctic.

We report on the second case of a reed warbler · great reed warbler hybrid (Acrocephalus scirpaceus and A. arundinaceus). The bird was captured during a standardised ringing session in Belgium in autumn 1999, and fell between the parental species in all measurements. Molecular analyses of two microsatellite loci verified that the bird was a female that had a reed warbler father and a great reed warbler mother.