How biodiversity response to changing climate feeds on to ecosystem processes underlying ecosystem services. Climate Change: Global Risks, Challenges and Decisions

Understanding how climate change will affect human well-being through its effects on ecosystem services is an urgent priority. Ecosystem services rely on a series of key ecosystem functions, with a given ecosystem service often depending on several ecosystem processes, and each ecosystem process often contributing to several ecosystem services. Changing climate affects ecosystem services in two ways: directly through abiotic modification of these ecosystem processes, and indirectly through its impacts on functionally-relevant biodiversity. This talk will focus on the indirect effects of climate on ecosystem services through its effects on biodiversity, using a review of the current state of the art and examples with special interest in agroecosystems and mountain ecosystems. We will first review knowledge on the linkages between biodiversity and ecosystem services, with a special focus on functional diversity. Then we will explore how effects of climate on biodiversity observed through experiments and projected with models are expected to cascade onto modifications of ecosystem services. Finally, we will demonstrate that although climate might have some direct effects on ecosystems within the next decades, past land use legacies and current management are primary determinants of ecosystem service delivery. Climate change effects are therefore complex, and are also likely to be indirect in the medium term, acting through the impacts of climate and climate-related policy on management. To conclude, sustainability options must consider looming effects of climate change on biodiversity and ecosystem functioning, as well as on demands that society might place on these ecosystems