Forest Degradation Assessment Framework based on Level-2 Ecosystem Integrity Concept

Climate change poses one of the most significant threats to forest ecosystems in the twenty-first century, intensifying the natural processes that drive forest degradation. The Food and Agriculture Organization (FAO) reports that forest degradation is increasing globally and is now outpacing deforestation, underscoring the need for robust methods to quantify degradation and support effective management strategies. The United Nations Strategic Plan for Forests (UNSPF) 2030, urges the need to increase efforts to prevent forest degradation and contribute to the global effort of addressing climate change. Recent advancements in forest degradation research highlight the potential of ecosystem integrity as a more comprehensive framework for assessing degradation. However, current applications of this framework still fall short, as they do not adequately evaluate the resilience of the forested ecosystem in the Anthropocene. Researchers also highlight the importance to go beyond the naturalness in ecosystem integrity concept and adapt a usable concept of level-2 ecological integrity based on the ‘new normals’ or ‘shifting baselines’. The need to address forest degradation both as a ‘process’ and a ‘state’ is also a key requirement to understand the current and critical stages of forest degradation as well as its variation in time. Since the ‘Water Budget’ controls the resilience of any ecosystem restoration, it is also important to analyze the changes in forest hydrological components while assessing its degradation. This study proposes a globally applicable, level-2 ecosystem integrity based framework for forest degradation assessment, incorporating the responses and resilience of forest systems for estimating the ‘process’ and ‘state’ of forest degradation. This will help to identify the pre-degrading, degrading and degraded stages of forests and will help to track the changes at a convenient time step. The framework integrates six forest integrity criteria and multiple associated indicators and evaluators, each representing critical forest characteristics. It also supports the identification of essential forest functions that are undergoing degradation, as well as those that remain intact—information vital for effective forest management. An Analytic Hierarchy Process (AHP) is employed to develop an integrated forest degradation index, which is then validated in a tropical forested river basin of the Western Ghats, India. The study area comprises 152 landscape units within the basin, maintaining approximately 80% forest cover. The assessment results indicate that in 2005, 47% of landscape units were classified as healthy–resilient, 42% as slightly stressed, and 11% as early-degrading. By 2020, these proportions shifted to 18%, 65%, and 17%, respectively. The trend indicates a steady rise in forest degradation, primarily due to the deterioration of ecosystem processes. This emphasizes the need to implement timely monitoring and climate adaptation measures in forest management, and this framework can form a vital part of such decision support systems (DSS).