New Landscape-Perspective Exploration of the Effects of Moso Bamboo On-Year and Off-Year Phenomena on Soil Moisture

On-year and off-year phenomena are common in Moso bamboo forests and significantly affect economic value and ecological functions. However, observational evidence regarding the impact of these cycles on surface soil moisture (SSM) remains scarce, and little is known about the implications of their landscape patterns for regional water conservation. Here, we first quantified the spatial distribution and temperature vegetation drought index (TVDI) of on-year and off-year Moso bamboo forests based on remote sensing images and landscape metrics. We then analyzed the role of on-year and off-year phenomena and their landscape patterns on SSM. Results showed that: (1) the proposed index derived from remote sensing imagery extracted on-year and off-year Moso bamboo forests with satisfactory accuracy, and the areas were 161.4 km2 and 173.5 km2, respectively; (2) a significant disparity was observed in the TVDI between on-year and off-year Moso bamboo forests, and mismatched growth stages and phenological characteristics were identified as primary influencing factors; and the (3) landscape metrics of the perimeter–area ratio (PAR), proximity index (PROX), perimeter–area fractal dimension index (PAFRAC), connectance index (CONNECT), and aggregation index (AI) exhibited negative correlations with the TDVI, indicating that the high spatial connectivity of Moso bamboo forests enhances soil water conservation. Our findings suggested that on-year and off-year phenomena and their spatial distribution intensified the heterogeneity in SSM. Therefore, considerations regarding the connectivity and edge complexity within Moso bamboo forests should be prioritized in future management strategies to achieve a balance between economic benefits and ecological functions in water-deficient mountainous areas.