Assessing rewilding’s influence on ecosystem resilience to disturbances

The accelerating climate change and biodiversity loss crises are causing a rise in global temperatures. As a consequence, disturbance events such as flooding, heatwaves, wildfires and drought episodes are occurring more frequently.

Rewilding is becoming a recognised approach to restoration that can reinstate the ecological stability of ecosystems, contributing to both biodiversity conservation and climate change goals. However, its potential for enhancing ecosystem resilience to disturbance is yet to be sufficiently assessed.

To address this, a recently published paper by the wildE project has conducted a global assessment of rewilding interventions to explore whether they could increase ecosystem resilience in terrestrial ecosystems, particularly under increasing pressure from climate change and its associated disturbances.

How can we assess the relationship between rewilding and ecosystem resilience?

To consider the influence of rewilding on ecosystem resilience, the review integrates two key frameworks. It draws on Perino et al.’s theoretical framework, which considers a rewilding intervention to foster self-regulating ecosystems by restoring trophic complexity, stochastic disturbance and connectivity. Additionally, it incorporates Lloret et al.’s Operational Resilience Framework, which outlines eight steps to identify resilience outcomes, with a particular focus on manageable factors, or “resilience predictors”, which can be modified within a system to increase its resilience.

By identifying Lloret et al.’s resilience predictors as the interventions aimed at restoring the three rewilding components defined by Perino et al. (biodiversity, stochastic disturbance and connectivity), the team conducted a meta-analysis of 42 scientific articles, including 305 different variables to assess the impacts of rewilding on ecosystem resilience.

The impact of rewilding on ecosystem resilience

The meta-analysis demonstrated that rewilding interventions generally enhance ecosystem resilience to various disturbances. As a result of increasing trophic complexity, restoring natural disturbance regimes and improving connectivity within ecosystems, 70% of 305 observations reported positive effects.

Despite these largely positive impacts, the paper finds that the effectiveness of the interventions is influenced by the nature of the disturbance. Rewilding interventions were found to be most successful in mitigating biotic disturbances, such as species invasions. Resilience to biotic disturbances was particularly enhanced by common rewilding actions, such as the introduction of herbivores and the removal of invasive plant species, as these interventions help restore ecological balance and promote self-sustaining ecosystems.

Rewilding was less effective, however, for increasing resilience when responding to extreme abiotic disturbances, such as intense drought or large-scale fire events. This limitation was particularly evident when the aim of the rewilding project was to restore the historical ecosystem (returning to the pre-disturbance state), suggesting that the species composition and structure promoted might lack the adaptive flexibility required to cope with rapidly changing abiotic conditions.

Where can we go from here?

The largely positive results highlight that rewilding has the potential to significantly enhance ecosystem resilience. However, its effectiveness is somewhat context-dependent and may eventually require complementary interventions to play out their full strengths. 

Whilst the authors emphasize the need for further data to fully assess the impacts of rewilding within socio-ecological systems, one potential approach to overcome some of the challenges could be harnessing abiotic disturbances to promote rewilding, using them as opportunities to foster ecosystem adaptation rather than strictly trying to resist or mitigate their effects.

Read more in the full study: Quantifying the impacts of rewilding on ecosystem resilience to disturbances: A global meta-analysis.