Analysis of landscape pattern changes in Ordos Relict Gull National Nature Reserve before and after ecological water replenishment

Abstract :BackgroundAs an important means of artificial intervention to replenish ecosystem water resources, ecological water replenishment plays an important role in soil and water conservation.In order to explore the impact of ecological water replenishment on the landscape pattern change of Ordos Gull National Nature Reserve, the water body area, vegetation cover, landscape type and spatial distribution of Ordos Gull National Nature Reserve before and after ecological water replenishment were compared, the impact of ecological water replenishment on the landscape pattern of the reserve was analyzed, and the impact of ecological water recharge on the landscape pattern change of the Gull Reserve was explored, and the research results were of great significance for the protection and restoration of degraded wetlands. Method In this study, ENVI 5.3 and ArcGIS 10.7 were used to extract water images of wetlands, as well as land use type classification, analyze the changes of water body area, vegetation coverage and landscape pattern before and after ecological water replenishment, use the land transfer matrix to explore the transfer trend of each land use type before and after ecological water replenishment, and finally calculate the landscape pattern index from 2000 to 2022 in combination with Fragstats. The influence of ecological water replenishment on the landscape pattern changes of the relic gulls reserve was further analyzed. Results (1) Before ecological water replenishment, the water body area began to shrink from the eastern part of the lake to reach a minimum value of 1.84 km2 in 2012. After ecological water replenishment, the water body boundary expanded to the east coast by 3.408 km in the first year, and the area increased by 4.2 km2, and maintained a fluctuating and increasing trend. (2) The proportion of cultivated land and grassland in the protected area before water replenishment reached 28.7% and 34.3%; After water replenishment, the proportion of water area increased from 2% to 5%; The values of the maximum patch index and the maximum landscape shape index increased, and the water body became the dominant patch type. (3) The values of the aggregation index and the spread index before and after hydration did not change much, and the connectivity was relatively stable. The values of Shannon Diversity Index and Shannon Uniformity Index first decreased and then increased, reaching 1.72 and 0.88 respectively in 2022, indicating an increase in landscape diversity. Conclusion This study shows that with the implementation of the ecological water replenishment project, the water area of Ordos Relic Gull National Nature Reserve has increased, the hydrological conditions have been improved, providing a "water base" for vegetation restoration, the vegetation coverage has been significantly improved, and the landscape pattern has become more complex and diversified, which has a positive effect on promoting the stability of the ecosystem, making the soil and water conservation effect more durable and stable, and providing a good living environment for rare and endangered birds. At the same time, this study expands the application dimension of landscape ecology in ecological engineering benefit assessment, and provides methodological reference for related research on similar wetland reserves.