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Biotic mechanisms of community stability shift along a precipitation gradient

Hallett, L.; Hsu, J.; Cleland, E.E.; Collins, S.L.; Dickson, T.L.; Farrer, E.C.; Gherardi, L.A.; Gross, K.L.; Hobbs, R.K.; Turnbull, L.; Suding, K.N.

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L. Hallett

J. Hsu

E.E. Cleland

S.L. Collins

T.L. Dickson

E.C. Farrer

L.A. Gherardi

K.L. Gross

R.K. Hobbs

L. Turnbull

K.N. Suding



Understanding how biotic mechanisms confer stability in variable environments is a fundamental quest in ecology, and one that is becoming increasingly urgent with global change. Several mechanisms, notably a portfolio effect associated with species richness, compensatory dynamics generated by negative species covariance and selection for stable dominant species populations can increase the stability of the overall community. While the importance of these mechanisms is debated, few studies have contrasted their importance in an environmental context. We analyzed nine long-term datasets of grassland species composition to investigate how two key environmental factors - precipitation amount and variability - may directly influence community stability and how they may indirectly influence stability via biotic mechanisms. We found that the importance of stability mechanisms varied along the environmental gradient: strong negative species covariance occurred in sites characterized by high precipitation variability, whereas portfolio effects increased in sites with high mean annual precipitation. Instead of questioning whether compensatory dynamics are important in nature, our findings suggest that debate should widen to include several stability mechanisms and how these mechanisms vary in importance across environmental gradients.


Hallett, L., Hsu, J., Cleland, E., Collins, S., Dickson, T., Farrer, E., …Suding, K. (2014). Biotic mechanisms of community stability shift along a precipitation gradient. Ecology, 95(6), 1693-1700.

Journal Article Type Article
Publication Date Jun 1, 2014
Deposit Date Apr 11, 2014
Publicly Available Date Apr 14, 2014
Journal Ecology
Print ISSN 0012-9658
Publisher Ecological Society of America
Peer Reviewed Peer Reviewed
Volume 95
Issue 6
Pages 1693-1700
Keywords Compensatory dynamics, Dominant species, LTER, Mean–variance scaling, Negative covariance, Portfolio effect, Taylor's power law.


Accepted Journal Article (2.3 Mb)

Copyright Statement
© 2014 by the Ecological Society of America

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