Landscape Pattern Change of Shengjin Lake Watland from 1993 to 2016 and its Response to Human Disturbance

Wetlands and oceans, forests are the three major ecosystems and it is one of the most important living environment of human being. Wetland change has a great impact on climate change, biodiversity, economic development, etc. It is of great significance for wetland conservation and management to study the change of wetland landscape pattern and the causes of the change. At present, the research on wetland landscape pattern change mainly focuses on the spatial-temporal law and driving force of wetland landscape change, but the relationship between landscape pattern index and driving factor needs to be further studied. In this paper, the Shengjin Lake wetland in Chizhou City, Anhui Province, was selected as the research object. Using the Landsat TM remote sensing data from 1993, 2000, 2008 and 2016, the maximum likelihood classification was used to extract the wetland. The landscape evaluation indexes such as patch density, maximum patch index, incense density evenness index, dominance degree and aggregation degree were selected to study the temporal and spatial changes of wetland area in this area by using landscape pattern index analysis method. The main causes of wetland change were also analyzed. The results show (1) The change of wetland area showed an upward trend from 1993 to 2000. The wetland area decreased continuously in 2000-2008 and 20082016, and the decline was smaller in 2008-2016. The wetland landscape area in 2000 was the largest, and the area was 144.973 km2. (2) From 1993 to 2016, the area of wetland and the largest patch in Shengjin Lake area first increased and then decreased, and the maximum patch index reached 10.55% in 2008. The shape of the patch was complicated, and the degree of human disturbance gradually increased. The landscape dominance of Shengjin Lake wetland is higher, but it shows the trend of decreasing first and then rising. (3) The influence of man-made interference on the area connectivity of the landscape wetland in the Lijin Lake area is weakened firstly, the influence of manmade interference on the shape of the wetland patch is large, and the main cause of the change of the wetland landscape area in the Shengjin Lake area is also the main reason. It is found that the wetland area of Shengjin Lake has been decreasing continuously since 2000, which is mainly influenced by human activities. What needs to be studied is the mechanism of interaction between landscape pattern and man-made disturbance in this area. It provides important basis for protection and management of Shengjin Lake wetland.