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Trophic Mismatches of Five Seabirds and Their Piscivorous Prey
Burthe, S., Daunt, F., Butler, A., Elston, D.A., Frederiksen, M., Johns, D., Newell, M., Thackeray, S.J. and Wanless, S. 2012. Phenological trends and trophic mismatch across multiple levels of a North Sea pelagic food web. Marine Ecology Progress Series 454: 119-133.

The authors introduce the report of their study by stating that "recent climate warming has significantly altered the phenology of a wide range of taxa across ecosystems (Thackeray et al., 2010) ... potentially disrupting the synchronization of key ecological interactions (Visser and Both, 2005)," while pointing out that "failure of a predator to overlap the period of peak resource demand (typically breeding) with peak prey availability may lead to 'trophic mismatch'," and noting that "such decoupling may alter food web structure," citing Cushing (1990) and Edwards and Richardson (2004).

What was done
Working in a portion of the North Sea (55 to 58°N, 3°W to 0°E), Burthe et al. "compared phenological trends for species from four levels of a North Sea food web over 24 years [1983-2006] when sea surface temperature (SST) increased significantly," starting with primary producers (phytoplankton), primary consumers (zooplankton), secondary consumers (sandeels), and finally focusing on five seabird predators - the common guillemot (Uria aalge), the razor bill (Alca torda), the European shag (Phalacrocorax aristotelis), the black-legged kittiwake (Rissa tridactyla) and the Atlantic puffin (Fratercula arctica) - all of which seabirds prey on current-year sandeels (Ammodytes marinus).

What was learned
The nine researchers reveal they found "little consistency in phenological trends between adjacent trophic levels, no significant relationships with SST, and no significant pairwise correlations between predator and prey phenologies," which they take as evidence that "trophic mismatching is occurring," such that prey length and, therefore, the prey's energy value "have declined significantly."

What it means
In spite of the significant trophic mismatches that Burthe et al. discovered over the course of their research - and rather surprisingly, we might add - they report that "to date, there is no evidence that these changes are impacting on the breeding success of any of the seabird species." Somehow, even birdbrains have learned to deal with the situation, suggesting that trophic mismatches need not be as deadly as sometimes presumed.

Cushing, D.H. 1990. Plankton production and year-class strength in fish populations - an update of the match mismatch hypothesis. Advances in Marine Biology 26: 249-293.

Edwards, M. and Richardson, A.J. 2004. Impact of climate change on marine pelagic phenology and trophic mismatch. Nature 430: 881-884.

Thackeray, S.J., Sparks, T.H., Frederiksen, M., Burthe, S., Bacon, P.J., Bell, J.R., Botham, M.S., Brereton, T.M., Bright, P.W., Carvalho, L., Clutton-Brock, T., Dawson, A., Edwards, M., Elliott, J.M., Harrington, R., Johns, D., Jones, I.D., Jones, J.T., Leech, D.I., Roy, D.B., Scott, W.A., Smith, M., Smithers, R.J., Winfield, I.J. and Wanless, S. 2010. Trophic level asynchrony in rates of phenological change for marine, freshwater and terrestrial environments. Global Change Biology 16: 3304-3313.

Visser, M.E. and Both, C. 2005. Shifts in phenology due to global climate change: the need for a yardstick. Proceedings of the Royal Society B 272: 2561-2569.

Reviewed 7 November 2012