Assessing the ecological integrity of mountain national parks' forest ecosystems under changing disturbance regimes: A systematic review

The changing climate is reshaping forest disturbance regimes, creating major uncertainties for sustaining the ecological integrity (EI) of mountain national parks. To address this, we conducted a systematic review of the impacts of changing disturbance regimes on forest ecosystems within mountain national parks. From 26 accepted peer-reviewed papers, we synthesized observed EI trends, ecological levels, spatial and temporal scales, EI attributes, assessment methods and metrics. Results revealed a predominant decline in EI, especially through losses of resilience, while stable or improved trends emerged mainly at broad spatial extents and long temporal scales, reflecting strong scale dependence. Assessments were biased toward structure, composition, and resilience, with limited attention to biodiversity and function, and they often relied on state-based rather than rate-based metrics. Methodologically, most studies used coarse-resolution models, with field surveys and remote sensing underrepresented, limiting the detection of fine-grain post-disturbance forest ecosystem successions. We identify three critical gaps: (1) insufficient assessment of ecosystem- and landscape-level EI trends, (2) limited use of high-resolution remote sensing methods and advanced metrics, and (3) lack of robust reference conditions to interpret post-disturbance changes. To advance EI assessments, we recommend integrating high-resolution remote sensing with models, expanding metrics to capture biodiversity, function, and rates of forest responses, and adopting multi-scale reference frameworks. These improvements will clarify how climate-driven disturbance regimes changes shape forest dynamics and provide stronger foundations for adaptive management of mountain national parks. • Predominant ecological integrity (EI) declines under changing disturbance regimes. • Strong spatial and temporal scale dependence of reported EI trends. • Assessments biased toward structure and resilience over biodiversity and function. • A framework integrates high-resolution remote sensing method and rate-based metrics.