Exploring Time-Lag Effects of Water Buffering in Wetland Soils on Vegetation Dynamics

Vegetation is not only directly influenced by water flow but also affected by the time-lag effects of water elements accumulated in the soil of wetland ecosystems. However, extensive studies have focused on the direct impacts of water on vegetation, with limited consideration of lag effects due to the lack of appropriate quantitative methods. This study aims to quantitatively determine the effects of two different forms of water on wetland vegetation. Using long-term Landsat data, three vegetation patches were extracted, and two types of hydrological variables (immediate and time-lag) were constructed to analyze their relationships. The results showed that: (1) Different vegetation patches exhibited distinct spatio-temporal dynamics over time. The distribution elevation of dense and high grass patches significantly decreased, and their ecological niche expanded; (2) The influence of hydrological variables on different vegetation patches varies: the sensitivity to immediate hydrological variables over time is sparse grass patch > dense grass patch > high grass patch; the influence of time-lag hydrological variables on vegetation decreases as the lag time increases. Vegetation at lower elevations is more affected by time-lag hydrological variables, with dense grass patches at moderate elevation experiencing the longest lag effects. This study provides useful insights into the effects of different forms of water on wetland vegetation, offering additional perspectives for future research on the dynamics between wetland water and vegetation.