Modeling Effects Of Climate Change On Ecological Landscape Pattern In The Three-River Headwaters Region

Climate change has exerted varying degrees of impact on agriculture,water resources,productivity,the cryosphere and coastline in China to a great extent,and it will be more harm than good in general.In particular,the further warming in the future will exacerbate this negative impact.Over the past 50 years,the climate over the Tibetan Plateau shows an overall trend of temperature rise and precipitation increase.The regional differences in climate are more obvious.Firstly,the ecological landscape classification system of the Three-River Headwaters Region(for short,called TRHR)was established refer to the research purpose and previous research.Furthermore,the evolution of the landscape pattern in the study area from 1980 to 2015 is discussed hierarchically from two aspects of quantitative structure and spatial pattern of ecological landscape,and the impact of landscape driving factors on the ecological landscape changes in the study area was analyzed.Then,the spatial distribution,trend change and abrupt change of temperature,precipitation and evapotranspiration over the past 50 years in the study area were statistically analyzed to explore the impact of climate cumulative effect on the ecological landscape pattern in the study area.Finally,the CA-Markov model that passes the validity test is used to predict the future ecological landscape pattern in the two development scenarios and the quantitative structure and landscape pattern characteristics of the prediction results are analyzed.The results are as follows:(1)The grassland landscape is the matrix of the ecological landscape pattern in the area and has an important influence on the function and ecological effects of the entire landscape pattern.During the study period,there were different degrees of transfer changes among various ecological landscape types,and a few landscape types were frequently transferred in and out.The landscape pattern in the study area tends to be more complex,the degree of fragmentation is deepening,and there is no significant variation in the shape characteristics.The landscape is generally distributed in a uniform trend.(2)Natural factors have a positive effect on the ecological landscape changes in the Sanjiangyuan region.Soil moisture and evapotranspiration play a positive role in the evolution of ecological landscapes.However,socio-economic factors have a negative effect on the ecological landscape changes in the study area,and the distance to the road in distance factors.The negative impact on the change of ecological landscape in the study area is greater.In the past 50 years,the temperature of the Sanjiangyuan region has generally shown a warming trend.There has been no significant increase in precipitation and evapotranspiration and no abrupt changes have occurred.Under different cumulative time scales,there are significant differences in the impact of climate change on grassland landscapes and non-grassland landscape areas.(3)It is predicted that the future ecological landscape pattern in the two development scenarios will show very different distribution characteristics and development trends.The ecological protection scenarios are more in line with the targets set in the "Three Rivers National Park Master Plan" and the second phase of the project planning.The degree of future landscape fragmentation will decline slightly compared with 2015,and the change of landscape pattern will be stable.In the natural development scenario,the various types of ecological landscapes undergo a violent transfer,the degree of futre landscape fragmentation is obviously reduced,and the landscapes are evenly distributed.