Plant community feedbacks and long-term ecosystem responses to multi-factored global change

14057R1If you add CO2 or nitrogen to a single plant it will likely grow more, but the amount by which each resource stimulates growth differs widely across species. When you add either resource to a whole ecosystem, total plant growth will likely also increase, but there will be winners and losers, causing a change in the relative abundance of plant species, and therefore altering the way the whole ecosystem responds to the added resource, a “community feedback”. Recent studies have shown that (1) shifts in plant community structure cannot be reliably predicted from short-term plant physiological response to global change and (2) the ecosystem response to multi-factored change is commonly less than the sum of its parts. In a new review published in AoB PLANTS, Langley and Hungate survey the results from long-term field manipulation to examine the role community shifts may play in explaining these common findings. They use a simple model to examine the potential importance of community shifts in governing ecosystem response and show that community dynamics can have a large impact on ecosystem response to any single factor. Understanding tradeoffs in the ability of plants to respond positively to, or to tolerate, different global change drivers may help identify generalizable patterns of covariance in responses to different drivers of change across plant taxa.