PALEOECOLOGY

Top-down or bottom-up?

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Science  11 May 2018:
Vol. 360, Issue 6389, pp. 616-617
DOI: 10.1126/science.360.6389.616-a

Was climate warming more important than megafaunal loss for shaping postglacial landscapes in Britain?

ILLUSTRATION: ALICE TURNER/STOCKTREK IMAGES/SCIENCE SOURCE

Primary producers and animal consumers interact to determine the structure and function of ecosystems, but how do their relative influences change over time? Jeffers et al. used the fossil record of the late Quaternary in Britain and Ireland to study whether the extinction of two-thirds of the native megaherbivores (including mammoths, giant deer, moose, and others) led to the observed expansion of woody plants at the end of the last glacial period. Instead, they found that more influential factors were a warming climate and reduction in fire, with an even more pronounced role for increasing shrub encroachment (followed by trees) in determining ecosystem structure. Plants and plant-soil feedbacks may have been more important than trophic interactions in driving the changes as northern ecosystems moved into the postglacial period.

Ecol. Lett. 10.1111/ele.12944 (2018).

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