Analysis of changes of Baiyangdian wetland from 1975 to 2018 based on remote sensing

Abstract

Baiyangdian Wetland is located in Xiong'an New Area, with important ecological functions and special strategic position. For a long time, under the combined effects of human activities and climate change, the Baiyangdian Wetland has gradually shrunk and even dried up. It is of great significance to further study the carrying capacity of ecological and environmental of the Xiong'an New Area by understanding the change characteristics and ecological functions of the Baiyangdian Wetland ecosystem. Currently remote sensing based analysis of changes of this region has insufficient in research periods, classification system and information interpretation of land use / land cover of wetland. This work studied spatiotemporal characteristics of changes of Baiyangdian Wetland from 1975 to 2018. Images of Landsat MSS/TM/ETM+/OLI during 1975-2018 and GF-2 PMS in 2017 and 2018 were acquired to analyze land use / land cover change. First, image interpretation symbol were built based on field survey of wetland types and their image features. Then, all images in ten periods were interpreted visually and land use / land cover were mapped out during 1975-2018. Last, we analyzed spatiotemporal characteristics of changes of Baiyangdian Wetland from changes of areas, types and landscape patterns. Results showed that areas of the Baiyangdian Wetland decreased 68.20 km2 (24.83%) from 1975 to 2018. Different characteristics were at different time periods. The wetland area was basically stable from 1975 to 1990, but decreased continuously from 1990 to 2011. In the period of 2011-2018 wetland area showed an increasing trend. The inter-transformation areas between types of wetland and non-wetland were mainly distributed in the transition region of water-aquatic plants-cultivated land-construction land, in the southern, western and northern parts of the Baiyangdian Wetland. In the past 43 years, the landscape pattern of Baiyangdian Wetland has become fragmented, complex and heterogeneous. Main uncertain factors affecting the analysis results include acquired time, such as month and year, of satellite images, classification systems and methods of land use / land cover. Changes in natural factors, such as climate, hydrology, as well as in human factors, such as water consumption from industrial, agricultural and urban, water resources projects in headwaters of baiyangdian basin, and groundwater exploitation, are the causes of the reduction and drying of the Baiyangdian Wetland.