Plant-soil feedback and climate change: Plant and soil communities modify ecosystem responses to climate change

Background/Question/Methods

The last two decades have witnessed a growing recognition that feedbacks between plant and soil communities have significant consequences for plant community dynamics and ecosystem processes. It is also becoming evident that plant-soil feedbacks are pivotal to understanding how climate change, and other global change phenomena, affects biodiversity, ecosystem processes, and fluxes of carbon between the biosphere and the atmosphere. In this talk, we illustrate how changes in both plant and soil communities, and interactions between the two, can modify ecosystem processes and their stability under climate change. To do this, we present results from three independent studies done at a range of spatial scales and in different ecosystems.

Results/Conclusions

First, using data from a field-based plant removal experiment combined with warming chambers, we show how changes in plant community composition can modify the influence of warming on peatland carbon dioxide fluxes. Specifically, we show that although plant community structure and warming independently affect carbon dioxide fluxes, the strength of the warming effect is dependent on vegetation composition. Second, using data from another field removal experiment we show how differences in grassland plant species composition modify the impact of simulated drought on ecosystem processes related to carbon and nitrogen cycling. Here, we show that certain drought responses that are mediated by belowground processes differ between functional groups, and that functional groups complement each other to increase ecosystem resilience to drought. Finally, we draw on data from a combined field and laboratory-based study to show how the resistance and resilience to drought of soil food webs differs under different land use systems. Specifically, we show that fungal-based food webs, and the processes of C and N loss that they govern, of grassland soil are more resistant and better able to adapt to drought than are bacterial-based food webs of wheat soil. These results indicate that land use strongly affects the resistance and resilience of soil food webs to climate change, and that extensively managed grassland promotes more resistant, and adaptable, fungal-based soil food webs. Collectively, the results of these studies are used to support our conclusion that shifts in both plant and belowground communities modulate the response of ecosystem processes to climate change.