Land Use Change Simulation And Ecological Effects Evaluation In The Manas River Basin

Clarifying the typical process of land use/cover change in an oasis in an arid area,and deeply understanding the heterogeneity of ecosystem services are conducive to the realization of land resource planning and sustainable development of the ecological environment in arid areas.This article selects the Manas River Basin under a typical Mountain-Oasis-Desert System(MODS)as the study area.Based on the land-use change process of the river basin in the past 40 years,it is targeted at each subunit and different land types.Characteristics,the CA-Markov model was used to simulate the current status of land use in the river basin in 2020,and its ecosystem service value was evaluated.The main conclusions are as follows:(1)From 1975 to 2015,the land use cover change in the Manas River Basin was relatively significant.The area of cultivated land,water area and construction land showed an increasing trend,and the area of woodland,grassland and unused land showed a decreasing trend.Among them,the area of unused land has decreased by 4.76×105hm2 in 2015.The proportion of cultivated land structure has increased from 12.89%in 1975 to 24.19%in 2015,and the total area has increased by 3.79×105hm2.The initial increase was 5 times,with an area increase of 0.3×105hm2;the overall performance of grasslands and waters showed an upward trend of fluctuations,with the smallest increase in grassland,with a cumulative increase of 0.15%in the past 40 years,and a large increase in waters,reaching 2.33%.The performance was down,with a decrease of 0.33%.(2)The overall simulation and partition simulation results show that The Kappa coefficient of each ecological subunit(Desert area:0.84>Oasis area:0.80>Mountain area:0.79)is higher than the overall simulated Kappa coefficient(0.77).The simulation of land-use change should consider the historical development process of the region,the development characteristics of different periods,and the characteristics of each ecological unit-level land type,and consider the actual conditions of the study area to select appropriate influential and restrictive factors to improve land.Take advantage of the accuracy of variation simulation.(3)The results of ecosystem service value evaluation show that the value of ecosystem services in the river basin increased from 1990 to 2015,and declined from 2015 to 2020.Among them,the positive value of mountain areas fluctuated between 1990 and 2015,and showed a decline from 2015 to 2020;the positive value of oasis areas showed a continuous upward trend after a small decline from 1990 to 1995;the positive value of desert areas was From 1990 to 2000,it showed an upward trend,and from 2000 to 2020,it continued to decline,reaching a peak in 2000.The total negative value of the oasis area increased significantly from 1990 to 2015,reaching an initial 2.63 times at the end of the period;it showed a decline from 2015 to 2020,with a cumulative decrease of 263.11×106yuan between 5a.From 1990 to 2015,the net value of ecosystem services in the study area increased,but the net value of per capita ecosystem services generally showed a downward trend.From 2015 to 2020,the net value of per capita ecosystem services rose slightly,and the environmental pressure in the river basin gradually eased.