Waterbird Populations and Pressures in the Baltic Sea

image of Waterbird Populations and Pressures in the Baltic Sea

This report outlines the results of the internationally coordinated census of wintering waterbirds in the Baltic Sea 2007-2009 undertaken under the SOWBAS project (Status of wintering Waterbird populations in the Baltic Sea). The estimated total number of wintering waterbirds was 4.41 million compared to 7.44 million during the last co-ordinated census 1992-1993. Despite the general declines stable or increasing populations of herbivorous species were recorded. While benthic carnivores with a coastal distribution have either shown moderate declines, stable or increasing populations seaducks with an offshore distribution have declined seriously. Based on analyses of trends in wintering waterbirds and pressures indicators are suggested as performance indicators in relation to the international and national actions taken to reduce the anthropogenic pressures in the Baltic Sea.



Diagnostics of distribution models

Approximate significance of smooth terms (Chi square and F values) of variables in the distribution model for Red-throated Diver/Black-throated Diver. Values for both model parts are presented on separate panels. The model was evaluated by fitting the model on 70% of the data set and testing the model on 30%. Evaluation results are presented as area under the receiver operator characteristic curve (AUC) for the presence/absence part and Spearman’s correlation coefficient for the combined model. Deviance explained for both model parts are shown. The presence-absence part was fitted by a binomial distribution, and the positive part by a gamma distribution.


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