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Keywords:

  • Benthos;
  • biological traits analysis;
  • cold winter;
  • ecosystem functioning;
  • functional diversity;
  • North Sea;
  • temperature anomalies

Abstract

Benthic epifauna was sampled in an area of 10 × 10 nautical miles in the German Bight. Samples were taken in January and July/August from 1998 to 2009. The ecological functioning of the epifaunal community was assessed using biological traits analysis (BTA). Twelve ecological traits of 26 epifaunal species were considered and analysed using non-metric multidimensional scaling (nmMDS). Anomalies in the sea surface temperature (SST) close to the study area were mainly above the long-term mean during the study period. SST was exceptionally high during the autumn months between 2002 and 2006. Additionally, the cold winter of 1995–96 was clearly reflected in strong negative SST anomalies. Trait composition changed in 2002, mainly due to a decreasing trend of traits related to an opportunistic life mode from 1998–2002. Traits related to reproduction showed a much clearer response to the high autumn SST anomalies from 2002 to 2006 than other traits. We concluded that the cold winter resulted in an increase in opportunistic species in the study area followed by characteristic post-disturbance succession stages to the point of an established community in 2002. This indicates a recovery time of epifaunal communities in the German Bight of 7–8 years. Additionally, the results give evidence that climate-induced variability of SST in the German Bight affects mainly the reproduction of epifaunal species rather than other traits such as feeding type.