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Beukema JJ, Dekker R
Variability in predator abundance links winter temperatures and bivalve recruitment: correlative evidence from long-term data in a tidal flat
Why does recruitment in bivalves vary so extremely between years and why are strong year classes arising almost exclusively after severe winters? A study of long-term data series on annual abundance of bivalve spat and of their main consumers (shrimps and shore crabs) on Wadden Sea tidal flats revealed that low winter temperatures reduced predator abundance in spring. Lower predation after cold winters strongly enhanced survival in tiny just-settled bivalve spat, resulting in high spat numbers in summer in cockles, mussels, and Baltic tellins. In the future, the frequency of cold winters is expected to decline by continuing climate warming. Downward trends in year class strength in some Wadden Sea bivalves are already present and are expected to continue.