Temperature tracking by North Sea benthic invertebrates in response to climate change

JG Hiddink 1, MT Burrows 2, J Garcia Molinos 3
1 School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK, J.Hiddink@bangor.ac.uk, @Macomabalthica
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.

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