Spatial and temporal evolution characteristics of the water conservation function and its driving factors in regional lake wetlands-Two types of homogeneous lakes as examples

Water conservation is the core wetland ecological function. The pattern of water conservation in geography often exhibits local spatial heterogeneity. In this paper, the Dongting Lake (DT) and Poyang Lake (PY) wetlands were taken as research objects, and the water yield (WY) module of the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was used to spatially quantify water conservation, with the aim of revealing the differences in water conservation in homogeneous wetlands. We observed spatio-temporal changes in the WY over six periods from 1998 to 2018 and used multivariate analysis of variance (MANOVA) and the system cluster method to explore the patterns and driving factors of water conservation in the DT and PY wetlands. The research results were as follows: (1) the WY in the two wetlands showed declining trends, but the trend in the DT wetland was more obvious. (2) Water conservation in the PY wetland exhibited a more sensitive response to climate than water conservation in the DT wetland. (3) From the perspective of the WY level, the PY wetland was generally high, while the DT wetland was generally low. (4) Climate change was the main contributor to and direct driving factor of water production, while wetland changes and socio-economic factors were indirect driving factors. (5) The effect of wetland cover changes on the WY showed significant differences among wetland cover types, indicating that the drivers of the WY changes had a clear relationship with landscape changes and transfers in wetland cover types. (6) The InVEST model was applicable for evaluating lake wetland water conservation. In summary, paying more attention to the differences in the changes in heterogeneous and homogenous regions can help us understand the factors that impact water conservation. Additionally, rational adjustment of indirect driving forces is conducive to ecological safety management.