Ecological landscape pattern changes and security from 1990 to 2021 in Ebinur Lake Wetland Reserve, China

Abstract

There is an increasing contradiction between humanity’s growing demand for natural resources and relatively limited supplements. Thus, ecological security has received widespread attention, making it a research hotspot in the global environment and an important topic in construction of ecological civilization. Ebinur Lake Wetland is a typical arid wetland area considered as a fragile and sensitive ecosystem. Quantitative monitoring of the ecological security and landscape patterns of the Ebinur Lake wetland ecosystem is of great significance for environmental protection. To clarify the relationship between ecological landscape indices and land use/cover, this study used Landsat TM/OLI data from 1990, 1998, 2011 and 2021, aimed to analyze the correlated spatio-temporal changes of Ebinur Lake Wetland Reserve, China over past 32 years, in addition to quantitatively evaluating changes in ecological security. The results showed that(1) During 1990–1998, forest and paddy areas increased, while the transformation between paddy fields and wetlands was frequent, and from 1998 to 2011, land use/land cover (LULC) changes gradually stabilized, vegetation recovery was halted, and the water area obviously decreased. Since 2012, Ebinur Lake area decreased by −3.88 % per year, while 44.8 km2 of the subsoils became extremely severe salinized. (2) The variability of ecological landscape in spatial structure and time dynamics is enhanced, landscape scalability declined, resulting in the intensification of fragmentation. CONTAG (Contagion index) decreased annually with the decline in Gobi area; whereas landscape diversity of wetlands increased with growing light and heavy saline-alkali areas. (3) Overall ecological security gradually increased from 0.56 to 0.65, and the unsafe areas first decreased, before increasing slightly. The total saline-alkaline land area continued to increase, indicating that desertification cannot be curbed. Ecological security had the highest sensitivity to landscape separation, and the value range and its safety levels of ecological security (ES) were accurately delimited based on uncertainty calculation and frequency statistics. The results can provide reasonable and practical suggestions for the government and local communities on how to strengthen the ecological environment construction of Ebinur Lake Wetland Reserve. The government should several water-saving measures, in addition to an inter-basin water transfer project can be implemented to help diminish the consequences of insufficient water resources, and planting salt-absorbing vegetation to slow the salinization process.