Study On The Change Of Land Use Pattern In Typical Small Watershed Of Loess Plateau

The Loess Plateau is the loess region with the most concentrated and largest area on the earth.It is also one of the regions with the most severe soil erosion and the most fragile ecological environment in the world.By using the “3S” technology,this paper explores land use patterns and dynamic changes in typical small watersheds of Nihegou?Zhifanggou and Wangdonggou,in order to achieve in-depth understanding of scientific research achievements in the study area and subsequent resources rational allocation,to achieve the harmonious development between economy and ecological environment in loess plateau,at the same time for the country's future in the loess plateau area mining resource potential,improve the ecological condition,regional economic prosperity,and solve the soil erosion provide theoretical reference for policy purposes.Using Satellite images(GF-1,ZY-3,SPOT-5),land use status data,historical yearbooks,social surveys,and interviews with old farmers as data sources,preprocessing and classification of image data using ENVI 5.5 and ArcGIS 10.3 Translation,access to the study area(Nihegou watershed in 1986,2002,2016;Zhifanggou watershed in 1986,1999,2015;Wangdonggou watershed in 1986,1990,2015)Type distribution map.The land use transfer matrix,land use dynamics,and conventional statistical methods were used to quantitatively analyze the area change and rate of change for each landscape type,combined with the landscape index in landscape ecology(selecting landscape level and landscape level),Using Fragstats4.2 to quantitatively analyze the evolution characteristics of the landscape pattern in the study area,and based on this,to discuss the driving mechanism of the pattern of land use pattern change in the study area in the past 30 years.The main conclusions of the paper include the following:(1)From the results of LUCC analysis,the common point of land use types in the three basins is that forest land,grassland,and construction land generally show an increasing trend.Compared with the other two watersheds,the total area of the Wangdonggou watershed is in an increasing trend,the proportion of cultivated land,unused land,and water areas has decreased in different proportions,and cultivated land,forest land,and grassland have predominated.Forest land,grassland,and unused land have shown a significant rate of change within the study and have changed in the past 30 years.The most obvious is the mutual transformation between forest land and grassland and garden land and cultivated land.(2)From the index analysis results of landscape level and landscape level,the landscape pattern changes significantly due to the intervention of human activities.Overall,the overall fragmentation of the landscape in the river basin is reduced,and the landscape dominance and preponderance are reduced.The connectivity of the blocks continued to increase,which was mainly due to the increase in the area of forest and grassland patches,and the enhanced control of the dominant landscape types on the landscape.(3)From the perspective of the driving forces for changes in land use patterns,the change in landscape pattern caused by natural factors is relatively small.Socio-economic factors play a key role in the change of land use patterns in various river basins.They mainly include population growth and structural changes,market economy,science technology,and policies,and they play in different periods.The main factors of influence are different,among which policies such as the protection of natural forests,returning farmland to forests(grass)and the Three-North Shelterbelt project have played a crucial role.(4)Based on high-resolution satellite imagery,this paper quantitatively analyzes the characteristics and laws of land use pattern change in typical small watersheds of the Loess Plateau on the scale of small watersheds,combines basic spatial analysis functions of ArcGIS and landscape index calculations,and analyzes them from the perspective of landscape ecology.Make analysis of land use patterns more convincing.Through the analysis of the driving mechanism of changes in land use patterns,it can be known that for these ecologically fragile areas in small watersheds in the Loess Plateau,it is necessary to continue implementing policies such as returning farmland to forests(grass)while protecting economic development,and to protect the returning farmland to forests(The results of grass)can ensure the restoration of ecological vegetation and sustainable development of the ecological environment in the Loess Plateau in the future.In addition,high-resolution satellite images provide more detailed data support for the analysis of the evolution of land use patterns.