| None of the elements of the natural environment has any influence on the topography;there is a close relationship between the production of human beings and topography.Topography is a variety of forms of the surface,is a basic component of the natural environment,the control of the natural environment and its differences and the impact of human activities on nature.The relationships among terrestrial ecosystems,climate change,and human activities are important aspects to consider in the field of global change.Terrestrial ecosystem is to provide the necessary animal and plant resources,and in maintaining ecological balance and water balance,regulating climate,degradation of pollution,rare animals and plants,etc.Climate factors such as light,temperature and rainfall will affect plant growth and distribution,thus forming different vegetation.At present,the focus on climate change and human activities,land use cover process caused by the ecological environment change,research fragile ecological system of regulation and control has become an important trend about the ecological environment change research in china and abroad.so,this study as a research object in Yanqi basin in Xinjiang,based on the Landsat remote sensing image data,DEM data and meteorological data,using the nonparametric mutation point inspection of climate change,Mann-Kendall trend analysis method(MK)as the main data source and field sampling data,through the land use and land cover dynamic monitoring,Land use/cover change(LUCC)trend analysis,To calculate comprehensive vegetation biomass,index and methods of LUCC dynamic combination,discusses the recent 40 a(1973-2014)the influence of different landform types of LUCC and biomass mechanism and response mechanism of climate change and human activities in Yanqi basin in Xinjiang,research on regional ecological environment evolution and its attribution.The result shows that:1.Topography aspects: Elevation of LUCC and space-time distribution and variation of biomass has significant impact;Slope direction on biomass and it's the influence of the change is not obvious;Area of cultivated land,glaciers and other land use types in various landform types in different changing trends;The influence of human activities on vegetation change and biomass are mainly distributed in 1049-1830 m altitude terrain is flat,due to the large number of land reclamation,artificial ecological restoration leads to the increase of cultivated land,wetland area and natural oasis and bare land area decreases;And in the area of 0 ~ 30 m human activity is the strongest,in more than 2000 m area of vegetation coverage,biomass is mainly affected by the natural factors such as climate change;A variety of topography area are bare land form in the study,bare land have decreasing trend during the study,land reclamation,climate warming is the main reason for reducing the number of bare land area.In the high mountain glacier area reduced,the main reason is that recent climate change is closely related.2.The climate change: The results showed that the MK trend test and mutations precipitation,evaporation,temperature and sunlight are the mutation point number in Yanqi basin.Nearly 40 years of mountains and plains average annual precipitation change showed a trend of increase in Yanqi basin;The mountains evaporation changes have decreasing trend,investigation on evaporation of the overall change showed declining volatility trend;In the plains the temperature increased;In a mountainous area have been increasing reduction and linear trend;The sun number in a mountainous area is reduced,increase the number of,reduce the volatility of the trend,reach significance level,in the plains have decreasing trend.3.vegetation cover change: LUCC analysis shows that,in mountainous areas,the areas considered to be bare land and glacier decreased 5.4 % and 3.36 %,respectively,whereas the highland vegetation increased by 8.76 %.In the plain area,the areas of the natural oasis,artificial oasis and wetland increased 1.96 %,15.41 % and 1.27 % respectively.The areas of desert and water decreased 1.62 % and 1.30 %,respectively;Mountain ecological environment is very sensitive to regional climate change,including precipitation,evaporation,the change of the climate factors such as temperature,sunshine number is decided to mountain vegetation survival state and the distribution of important factor;The promoting function of human activities and climate change beneficial support are the reasons for the upturn in oasis plain ecosystem;The population has increased dramatically and social and economic rapid development,cause oasis plain ecological system structure and the main factors of time and space distribution.4.Spatial and temporal variations of land use types: In the plains,before and after the characters in the early 1970 s and 2000 wetland into water,high water period other times waters into a wetland;during the period of 1977-2014 wetland keep into cultivated land;in the mountains,during the entire study glaciers into cold meadowsteppe;Mountain glacier area to reduce the Tianshan mountain glaciers and the trend of area change trend was consistent;The change of desert area is not obvious.All kinds of land use/cover type dynamic spatial and temporal variations of each are not identical.Throughout the study period,space-time dynamic is a net increase of trend of cultivated land.Nearly 42 a various landform type's area proportion of each land use type,biomass and its change rate is different in Yanqi basin,Xinjiang.High ground biomass decreases with the increase of altitude,first increase trend. |
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