ANALYSIS OF HYDROLOGICAL CONNECTIVITY DYNAMICS OF THE WETLANDS IN HONGHE NATIONAL NATURE RESERVE

Due to the intense agricultural development and other human activities in the Nongjiang catchment in the 1980s, the runoff of Nongjiang River was cut off The hydrological connectivity of wetlands in the Honghe National Nature Reserve (HNNR) has been changed remarkably. Maintenance of a good connectivity is one of the key factors to protect the biodiversity and sustain the ecosystem stability and integrity. However, quantitative studies on hydrological connectivity of wetlands and corresponding restoration measures are rarely. Therefore, the aim of our research was to quantify hydrological connectivity of wetlands and propose effective recovery measures. Instead of single quantitative approach, based on the remote sensing image of wetlands in HNNR from 1975 to 2006, we applied the integral index of connectivity (FIC), probability of connectivity (PC), and lacunarity index to analyze the changes in wetland connectivity. The results showed the declining trends of landscape connectivity measured by the integral index of connectivity (HC) and probability of connectivity (PC) from 1975 to 2006. The importance of connectivity in each wetland patch varied with the increment of dispersal distances, and some important habitat patches, which exhibit a potential to enhance landscape connectivity, should be given more attention. The results also suggested that lacunarity index analysis shows that the spatial heterogeneity of wetlands varied in different scales, and the scale transformation could reflect the degradation process of wetlands which was consistent with wetland hydrological connectivity analysis. The result of this study provided basic data and a scientific guidance for future wetland restoration.