A review of dryland ecosystem resilience improvement under the integrated impacts of climate change and tree restoration

Dryland ecosystem resilience is increasingly threatened by increasing aridity under climate change. While large-scale tree restoration offers a potential mitigation strategy, its effect integrated with climate change pressures on ecosystem resilience remains unquantified, hindering science-based restoration guidance in drylands. Our systematic review, analyzing 435 core publications, reveal three critical research gaps: (1) the lack of a unified definition of ecosystem resilience and an imbalance in its standardized assessment methods across its three core dimensions: resistance, recovery, and adaptability, a focus evidenced by publication ratios of over 7:1 and 12:1 for recovery and resistance versus adaptability, hindering a unified, three-dimensional quantification; (2) An pronounced imbalance in aridity thresholds research, with a predominant focus on vegetation attributes such productivity and cover (48%) contrasted by scant attention to holistic ecosystem properties like stability, recovery, resistance, or resilience (a mere 6%); and (3) the absence of integrated models capable of simulating the integrated impacts of climate change and tree restoration on ecosystem resilience dynamics. To address these challenges, this study proposes a comprehensive framework that synergizes theoretical mechanisms, technical tools, and ecological management. The core of this framework includes a three-dimensional assessment method for ecosystem resilience, and a coupled modelling approach that combines climate change (e.g., from CMIP6) with tree restoration modules (e.g., using Budyko models and atmospheric moisture tracking) to simulate future aridity. The application of this framework is designed to identify critical aridity thresholds and elucidate ecological regulation mechanisms, thereby providing a quantitative basis for optimizing tree restoration practices and enhancing dryland ecosystem resilience under climate change.