Lyons et al. 2016 - K. Lyons

Holocene shifts in the assembly of plant and animal communities implicate human impacts

Blog by Kate Lyons

Authors:

S. Kathleen Lyons, Kathryn L. Amatangelo, Anna K. Behrensmeyer, Antoine Bercovici, Jessica L. Blois, Matt Davis, William A. DiMichele, Andrew Du, Jussi T. Eronen, J. Tyler Faith, Gary R. Graves,  Nathan Jud, Conrad Labandeira, Cindy V. Looy, Brian McGill, Joshua H. Miller, David Patterson, Silvia Pineda-Munoz, Richard Potts, Brett Riddle, Rebecca Terry, Anikó Tóth, Werner Ulrich, Amelia Villaseñor, Scott Wing, Heidi Anderson, John Anderson, Donald Waller & Nicholas J. Gotelli

This research demonstrates that there has been a fundamental shift in community structure due to human activity. We evaluated the co-occurrence structure of plant and mammal communities using both fossil and modern datasets. The relative proportions of significantly aggregated and segregated species pairs were stable for 300 million years before abruptly changing approximately 6000 years ago.  We tested this finding against several possible biases and found that none of them could explain our data.  The timing of the shift coincides with increasing human impacts such as increasing population size and the spread of agriculture. Our study thus indicates that the processes acting on ecological communities today may be unique in the history of land ecosystems.

These results are important because of the intensifying debate about global change and biodiversity loss.  Human activity is changing the world in myriad ways, and the deep time perspective represented by our research can heighten awareness of the magnitude of human ecological impact. Demonstrating that even humans without advanced technology were able to cause a fundamental change in the long-lasting (300 million years) co-occurrence structure of land plant and mammal communities is an important result to communicate to the public, many of whom continue to express skepticism about the effects of our current environmental impacts.