Climate change – Approach 3

Microbial resistance and resilience in response to extreme drought

Drying and rewetting cycles can have strong impacts on soil microbial communities, modifying the resilience of microbially-mediated processes to extreme drought events. Field-collected soil from monospecific and mixed tree stands are incubated in the microcosm platform at the European Ecotron in Montpellier and exposed to extreme drought events with subsequent rewetting. We assess the resistance and resilience of process rates in response to drought and the relationships to diversity with measurements of microbial-driven processes by measuring CO2 and N2O fluxes before and after the drought event and after rewetting.

Ecosystem resistance and resilience to extreme drought

In an experiment in the mesocosm platform of the European Ecotron in Montpellier (sixteen units with a surface area of 1m2 and a soil depth of 1m each), we manipulate the functional diversity of soil fauna to test ecosystem responses to an extreme drought event. The use of the Ecotron mescosms allows us to test the interactive effects of increasing soil functional diversity and extreme drought on ecosystem scale H2O and CO2 fluxes, and to evaluate ecosystem resistance and resilience to drought.


Interactive effects of climate change and changing tree species diversity

With a third approach addressing interactive effects between biodiversity and climate change, we include two planted-tree diversity experiments that combine tree species richness gradients with climate change treatments, notably the ORPHEE (France, watering treatment to avoid summer drought) and FORBIO (Belgium, a 30% rain exclusion) experiments. We measure soil fauna diversity in monospecific and mixed tree stands to evaluate potential interactive effects of tree diversity and climate change on soil organism diversity and function.

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