COS 217-3 - Guiding ecosystem restoration with critical transition theory: Lessons from drylands

Abstract: Alternative stable states have been documented in several ecosystems worldwide. Indicators of critical transitions between these states are based on theoretical understanding of ecological resilience. These theoretical developments could inform and guide restoration practices practically. Major restoration efforts have been devoted to halting and reversing dryland degradation and desertification trends worldwide. In this study, we combined remote sensing (satellite images & drone images), field surveys and mathematical modelling to assess the large-scale ecological restoration practices of sand dune systems in China and explore the links between theoretical expectations and practical outcomes.

The frequency distribution of NDVI suggests a co-existence of two distinct stable states in sand dunes, i.e. active bare dunes and stabilized vegetated dunes. The resilience of these states varies along the precipitation gradient. We used this result to further map future sand dune states and restoration potential under different climate change scenarios.

Our field assessment shows that ecological restoration efforts, at proper locations, can facilitate dune transitions from an active bare state to a stabilized vegetated state. Coupling these field observations with high-resolution drone imagery reveals that vegetation spatial patterns, as predicted theoretically, can indeed signal dune restoration success and can therefore guide ecosystem restoration plans.

Mathematical modelling further demonstrates that accounting for spatial heterogeneity and spatial interactions can facilitate the optimal restoration design for ecosystem restoration in spatially extended ecosystems with alternative states.

Our work demonstrates how bridging restoration ecology and theoretical ecology can facilitate the understanding of dryland resilience, as well as help identifying effective and sustainable restoration practices that promote ecological resilience.