Analysis of wetland dynamic change and ecological health in Wuliangsuhai based on multi-temporal remote sensing image

The traditional methods of sampling plays an important role in the wetland ecosystem health assessment, but there also exists some problems such as a waste of human and financial resources and the limition of the number of sampling points. Remote sensing technology can obtain surface data for long time series, which has important advantages in wetland structural change and ecological health assessment. In this paper, the characteristics of wetland structure of Wuliangsuhai in the past 40 years from 1977 to 2015 were studied by using multi-temporal LandSAT data. The driving factors of wetland structure change were analyzed. The ecological health of Wuliangsuhai wetland was evaluated based on the pressure-state-response (PSR) model. The results showed that: (1) In 1997, the wetland structure was dominated by the water, and the water area was 61.70% of the whole wetland area. With the decrease of the water area and the increase of the reed area, the reed and water became the main types of wetland structure during the period from 1998 to 2006. The total area of wetland was 50% higher than that of wetland in 2015, and the structure of wetland was changed from water to reed in 1977. (2) The ecological health status of Wuliangsuhai wetland was in an alert state from 1977 to 1996. The ecological function level of the Wuliangsuhai wetland was degraded, but the ecological system could be maintained. The ecological health status of the Wuliangsuhai Wetland in 2006 and 2015 changed from the original alert state to a good state, but the comprehensive evaluation index was in the lower limit of the good condition, which indicated that the ecological health status of the Wuliangsuhai wetland had improved, the external pressure was decreased but not obvious. The results provide scientific basis for the management of Wuliangsuhai wetland, and have important reference value for monitoring the structure and health status of wetland via remote sensing data.