DIV4DROUGHT

Tree diversity effects on forest drought resilience: a mechanistic approach to reconcile divergent observations

© Nicolas Martin-StPaul ; Mixed forest in the Écrins Massif (Valgaudemar).

Widespread drought-induced tree mortality threaten forests and ecosystem services, highlighting the need for strategies to enhance forest resilience. Increasing tree species diversity is a promising approach, yet its effects on drought resilience remain unclear.

The DIV4DROUGHT project will allow the innovative exploration of this long-standing blind spot of tree diversity effects on forests by: 1) conducting a meta-analysis of existing evidence for tree diversity effects on forest drought resilience and its components, resistance and recovery; 2) creating a global open-source database of tree hydraulic traits (linked to water transport and use) as predictors; and 3) using process-based forest dynamics models to evaluate underlying mechanisms.

The explored mechanisms will include complementarity effects on water use in space and time, micro-climate buffering (facilitation effect) or improved water status of tolerant species resulting from the higher mortality of drought-sensitive species during extreme drought (“fuse effect”). This interdisciplinary effort will have important implications for forest management and conservation under climate change.