Area changes and driving factors of small and micro wetlands in Jilin Momoge National Nature Reserve

Small and micro wetlands play an essential role in maintaining biodiversity and ecological balance. However, because of their limited spatial extent and high susceptibility to evaporation, they are particularly sensitive to climate change and human disturbance, and therefore prone to degradation and loss. Taking the Jilin Momoge National Nature Reserve as the study area, this study selected six phases of remote sensing images from 1994 to 2020 and combined landscape pattern index analysis with a geographically weighted regression model (GWR) to quantify changes in the area and number of small and micro wetlands, characterize their landscape fragmentation, and identify the mechanisms through which climatic and anthropogenic factors jointly influence wetland dynamics. The results show that the area of small and micro wetlands decreased by 17.12% during the study period, while the number of wetland patches declined by 36.71%, indicating a clear trend of wetland shrinkage and increasing landscape fragmentation. The GWR results further reveal that, among climatic factors, evaporation was the dominant driver of wetland area reduction. Increased evaporation intensified water loss in small and micro wetlands, thereby weakening their hydrological stability and accelerating ecological degradation. At the same time, the expansion of saline-alkali land further aggravated water depletion, vegetation degradation, and overall wetland shrinkage, suggesting that climatic stress and land surface degradation can interact to amplify ecological vulnerabilityIn terms of human disturbance, cultivated land development and proximity to roads were found to intensify the fragmentation of small and micro wetlands. Agricultural expansion altered the surrounding land-use structure and compressed wetland habitats, while road networks increased landscape separation and weakened ecological connectivity. These factors jointly contributed to the decline in wetland patch integrity and the deterioration of wetland landscape patterns. The spatial heterogeneity analysis indicates that small and micro wetlands in the southwestern part of the reserve experienced significant degradation under evaporation stress, showing stronger ecological vulnerability in areas with relatively weak hydrological support. In contrast, small and micro wetlands in the eastern part benefited from the hydrological regulation capacity of adjacent large wetlands, which helped form an ecological buffer zone and reduced the intensity of degradation. This spatial difference confirms the effectiveness of differentiated zoning-based conservation strategies. Overall, the study demonstrates that the degradation of small and micro wetlands in the Momoge National Nature Reserve is the result of combined climatic and anthropogenic pressures, with evaporation, saline-alkali land expansion, cultivated land development, and road proximity serving as key influencing factors. The findings provide a scientific basis for the protection, restoration, and spatially targeted management of small and micro wetlands in the reserve.