JG Hiddink (1), MT Burrows (2), J Garcia Molinos(3)
2 Scottish Association for Marine Science, Scottish Marine Institute Oban, Argyll PA37 1QA, UK
3 Scottish Association for Marine Science, Scottish Marine Institute Oban, Argyll PA37 1QA, UK
The extent to which shifts in the distribution of species keep pace with a changing climate is uncertain. In particular, little information exists for soft-sediment invertebrates. We evaluate changes in the distribution of 65 benthic invertebrate species over 14 years by combining information on their geographic, bathymetric and thermal niche shifts and tests whether species are tracking their thermal niche as defined by minimum, mean or maximum bottom (SBT) and surface (SST) temperatures. Temperatures increased in the whole North Sea over the study period, with many benthic invertebrates showing north-westerly range shifts and deepening. Nevertheless, distribution shifts for most species lagged behind shifts in both bottom and surface temperatures, resulting in a large proportion of species experiencing higher temperatures in 2000 than in 1986. The velocity of climate change (VoCC) of mean SST accurately predicted both the direction and the magnitude of distribution centroid shifts, while maximum SST did the same for contraction of the trailing edge. The VoCC of SBT was not a good predictor of range shifts as it only accurately predicted the direction but not the magnitude of centroid shifts. Our results show that marine invertebrates need to shift at different rates and in different directions to track the climate velocities of different temperature measures, and are therefore lagging behind most temperature measures. If these species cannot withstand a change in thermal habitat, this could ultimately lead to a drop in benthic biodiversity over longer time scales under rapid climate change.