2018 ESA Annual Meeting (August 5 -- 10)

COS 39-5 - Species asynchrony can stabilize primary production against climate variability

Tuesday, August 7, 2018: 2:50 PM
340-341, New Orleans Ernest N. Morial Convention Center
Benjamin Gilbert, Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada, Andrew S. MacDougall, Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, Taku Kadoya, Center for Environental Biology and Ecosystem Studies, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan, Munemitsu Akasaka, National Institute for Environmental Studies, Tsukuba, Japan, Joseph R. Bennett, Institute of Environmental Science, Carleton University, Ottawa, ON, Canada and Nutrient Network, Multiple Institutions
Background/Question/Methods

Plant communities can buffer the effects of climate fluctuations when species-specific responses generate asynchronous dynamics that stabilize community-level properties such as primary production. Climate fluctuations will be destabilizing when these compensatory mechanisms fail to emerge in communities, such as when large fluctuations in temperature or precipitation cause synchronous responses among species. However, conditions under which climate variability strengthens or weakens asynchrony are poorly understood. Theory suggests that extremely high variability will cause a decline in asynchrony, but it is unclear how large this variation would have to be to cause such a decline, or whether different bioclimatic regions would show distinct responses to climate variability. These knowledge gaps limit global predictions about the effects of increased climate variability on asynchrony and ultimately primary production. To address this gap, we examined 31 grasslands in five bioregions on three continents over a half-decade. We asked (1) whether species asynchrony is associated with community-level temporal stability of net primary production, measured as the temporal mean Annual Aboveground Biomass Production (AABP) divided by its standard deviation; (2) if asynchrony responds to among-year fluctuations in precipitation and temperature as a globally generalizable relationship; and (3) if and under what conditions climate variability is sufficiently large that climate-asynchrony relationships weaken with further increases in variability.

Results/Conclusions

We found a globally consistent trend of greater stability of primary production with increased asynchrony. Asynchrony in turn increased with moderate variation in precipitation, but declined with larger fluctuations; these larger fluctuations were observed in grasslands of most bioregions in the world. Temperature variation also caused a unimodal change in asynchrony, with this variation surpassing peak asynchrony in Europe and parts of North America. Both precipitation and temperature responses were consistent among bioclimatic regions, although regions experienced different levels of climate variability. Our work demonstrates that asynchrony of species responses to climate is able to stabilize primary production across a wide range of species and conditions but, in highly variable environments, asynchrony declines and is not sufficient to stabilize primary production. Given current levels of climatic variation, these results imply that approximately half of all grasslands will become less stable with even small increases in climate variability.