Analysis of Forest Landscape Restoration Based on Landscape Connectivity: A Case Study in the Yi River Basin, China, during 2015–2020

Abstract

Landscape connectivity has widely been recognized as one of the key objectives in studies of forest landscape management, ecological conservation and construction. Protecting virgin forests and afforesting marginal cropland are two long-term ecological projects in China. However, along with rapid urbanization and industrialization in China, the relationship between landscape connectivity and forest landscape restoration (FLR) has not been fully explored. The emergent question concerns whether the connectivity of a restored forest landscape could benefit the local flora and fauna. We evaluated the status of FLR in the Yi River watershed based on remote sensing images during 2015–2020. The forest landscape connectivity (FLC) was investigated using landscape connectivity indicators, applying the theory of landscape connectivity. We also examined the variations of FLC under different landform types (hills and low mountains) according to distance threshold values ranging from 100 m to 20,000 m. The most appropriate distance thresholds for analyzing FLC in hills and low mountains are 500 m and 100 m, respectively. The results showed that in this period, the FLC in low mountains was increased, whereas that of hills was decreased. The contributions for reforested patches on the improvement of the FLC were evaluated. In hills, patches that made “very high” and “high” contributions to improve the FLC occupied 15.6% of the total reforested area, whereas the proportion in low mountains was 25.5%. The results indicated that although rainfed cropland patches have been converted to forest patches, some of them have made small contributions to the FLC. Through this case study, we hope to have confirmed that landscape connectivity analysis could be used as a criterion for selecting important patches in the planning of FLR. Moreover, we have introduced this implementable method for future ecological restoration management programs.