Advancing Forest Fragmentation Analysis: A Systematic Review of Evolving Spatial Metrics, Software Platforms, and Remote Sensing Innovations

Context Forest fragmentation—the breakup of continuous habitat into isolated patches—alters landscape processes and biodiversity. Rapid advances in sensors and computing have diversified diagnostic methods, but comparability and ecological linkage remain uneven. Objectives Synthesize 138 methodological studies (1990–2025) to: (i) chart shifts in metric families, including emerging 3-D approaches; (ii) assess how data and processing choices shape indicator performance; and (iii) distill limits and reporting practices that improve portability. Methods We reviewed studies using lidar/TLS and Sentinel-2 inputs, change detection, and indicators implemented in landscapemetrics, GuidosToolbox, and Google Earth Engine, tracing transitions from patch/edge metrics to morphology-aware roles, connectivity, fixed-window density, and 3-D/voxel measures. Results The field is moving toward morphology-aware roles, multiscale connectivity, fixed-scale density, and vertical structure. Five recurring limits are: scale sensitivity and habitat-amount confounding; region-tuned parameters that hinder transfer; scarce field validation of global/automated products; weak or inconsistent biotic links of structural metrics; and incomplete reporting that curbs reproducibility. Gaps include uneven tropical coverage and limited 2-D/3-D cross-walks. Priorities are transparent parameterization and sensitivity checks, precise documentation of spatial/detector settings, region-specific benchmarking, shareable workflows, and integration of field data. Summary Standardizing documentation, validation, and cross-scale linkages can improve the reliability of fragmentation measures for monitoring and conservation. Emphasis should be on refining and harmonizing existing methods rather than proposing new indices