STUDY ON SPATIAL-TEMPORAL CHANGES OF LANDSCAPE PATTERN OF LAND USE IN YICHANG-WUHAN SECTION OF THE YANGTZE RIVER IN RECENT 20 YEARS

To understand the utilization status of shoreline resources and provide scientific basis for ensuring the development of shoreline resources and ecological environment protection, this study analyzed the land use type area and landscape pattern index in different periods in the 1 km area along the shoreline of Yichang-Wuhan section of the Yangtze River using Taking land use in 2000, 2005, 2010, 2015 and 2019 as data sources. The results showed that the land use types were mainly farmland and building land from 2000 to 2019. The obvious features of the change included 9.39% decrease in farmland area in 2019 compared to 2000, expanded building land and forestland, and the more intense transformation between farmland and building land. The study area was rich in wetland resources, with the total wetland area accounting for over 70%, and the constructed wetland accounting for over 92% of the total wetland area. In the class level, the patch number in each land type increased obviously, and landscape fragmentation occurred in different degrees. The forest land area increased by 35.63 km², but the patches number increased from 0.114 million to 0.618 million, the landscape shape index increased from 34.92 to 95.19, and the landscape aggregation index decreased by 10.82%. The patches tend to be fragmented and irregular in shape, which will hinder gene exchange among populations, change the biogeographic environment for species survival, and reduce the diversity of biological species. The compact structure will weaken the inhibition of some disturbances such as insect disasters and fires. In the landscape level, the patches number increased from 1.24 million to 2.34 million, Shannon diversity index increased by 0.14, and contag index decreased by 8.48%. The fragmentation of landscape in the whole study area has intensified. The original dominant patch types in the region were broken, the dominance gap has gradually narrowed, the spatial connectivity has decreased, and the spatial advantage has weakened. This study provides a basis for optimizing the landscape pattern and protecting the ecological environment of the Yangtze River.