Study On The Dynamic Change And Response Of Forest Landscape Pattern

In recent decades,with the vigorous development of various towns and cities in Tibet,their land use types and landscape patterns have undergone unnoticeable changes under the combined influence of human and natural environments.Based on the characteristics of large regional area and rapid changes in landscape patterns in Tibet itself,we now take the Shedra National Forest Park as an example to monitor and analyze it,further improve the study of land use landscape patterns in Tibet,and provide an important theoretical basis for the healthy development of the Shedra Mountain ecosystem and the protection of various landscapes.Taking the Tibetan Sera National Forest Park as the research object,the landsat TM images in 2000 and 2010 and Landsat8 images in 2020 were used as the data base,combined with the knowledge of landscape ecology principles and other software such as EVNI5.3,Arc GIS10.6,Fragstats4.2,SPSS,etc.from land use change,landscape pattern index,the coupling relationship between soil factors and vegetation,and the relationship between landscape pattern and environment to quantify the landscape pattern of Sedgera National Forest Park,and the results are as follows:(1)Analysis of land use dynamics in Sedgera National Forest Park:the overall area of forest land increased from 1,424.98 km~2 to 1,905.06km~2 from 2000 to 2020,the area of unused land decreased,the vegetation cover increased,and the area of dry land and construction land increased;the most amount of land use transfer was from grassland to forested land,sparse forest land and dry land,with a cumulative transfer of 791.50 The change in the area of water area is the most stable;the attitude of land use is: construction land > open forest land > dry land > shrubland > unused land > forested land > water area > grassland.(2)Analysis of landscape pattern changes in Sedgera National Forest Park: Grassland and forested land are the main substrates in the study area,the main landscape types in the park tend to be regular in shape,landscape heterogeneity increases,the overall landscape type connectivity increases,fragmentation decreases,landscape types are arranged more closely,landscape distribution is more concentrated,landscape richness increases and distribution is uniform,changes in forest landscape types in the park tends to be stable.(3)Soil physical properties: The soil bulk weight of Sedgera National Forest Park varies from 0.5631 g/cm~3 to 1.1386 g/cm~3,soil water content from 24.03% to 76.34%,total soil porosity from 58.35% to79.42%,and soil mechanical composition is mainly powder and sand.Plant nutrient elements: the total plant nitrogen content of Sedgera National Forest Park ranges from 1.872 mg/g to 22.33 mg/g,the total plant phosphorus content from 0.183 mg/g to 3.669 mg/g,and the total plant potassium content from 2.142 mg/g to 71.86 mg/g.The differences in soil physical properties and plant nutrient elements are significant at different altitudes.(4)Study on the relationship between soil factors and vegetation in Sedgera National Forest Park: Between soil factors and plant nutrients,there is a significant positive correlation between soil capacity and plant total nitrogen content,while the correlation between the rest of indicators is not significant.Between soil factors,there is a significant negative correlation between soil bulk weight and soil water content and total soil porosity,a significant positive correlation between soil water content and total soil porosity and soil powder particles,and a significant negative correlation with soil sand particles.(5)Study on the relationship between landscape pattern and environment in Sedgera National Forest Park: the landscape pattern changes of dry land,forested land,shrubland,open forest,grassland,and unused land have significant correlation with the average annual temperature,only the maximum patch index of water has significant correlation with the average annual temperature,and the pattern of precipitation and landscape pattern changes in Sedgera National Forest Park is not obvious,indicating that the average temperature has a significant effect on the landscape pattern changes in Sedgera The effect of average temperature on the change of landscape pattern in Sedgera National Forest Park is more significant.