Abstract: The severe shortages of water resources have become a global issue. Water conservation as a function of forests is becoming more and more important to sustainable development. However, the difference of water conservation capacity among various vegetation types and different seasons is still unclear. In this study, we analyzed the seasonal and spatial variations of water conservation capacity of different vegetation types (i.e., evergreen broadleaved forest, meadow, coniferous forest and dwarf forest, coniferous and broadleaved mixed forest) along an elevation gradient in Wuyishan National Park. Water conservation capacity was represented by an index calculated by the ratio of normalized difference vegetation index (NDVI; i.e., calculated from Sentinel-2 images, which obtained from 2017-2020) to mountain slope (i.e., calculated from the Digital Elevation Model (DEM)). The results showed that this index was feasible to monitor water conservation capacity of different vegetation types in different seasons. The water conservation capacity of all vegetation types in different seasons was autumn > summer > spring > winter. The spatial distribution of water conservation capacity across the elevation gradient was consistent with vegetation distribution. Water conservation capacity of the four vegetation types across different seasons was in order of evergreen broadleaved forest > coniferous and broadleaved mixed forest > coniferous forest and dwarf forest > meadow.

Key words: water conservation capacity index model, normalized difference vegetation index (NDVI), slope, seasonal variation, elevation gradient.