| As a high quality gene pool for the study of temperate fruit trees,wild fruit forests are of great significance in the study of the origin,species evolution and genetic diversity of fruit trees.With ili river valley as the study area,with the wild fruit wood as the research object,by using GIS,RS,spatial geological statistics,the theory of landscape ecology,on the present status of wild fruit wood fragmentation,fragmented dynamic process and driving force analysis,and by using CA-Markov model analysis and wild fruit wood survival risk,to deepen the cognition to the wild fruit wood ecological system in the study area,To provide reference for wild fruit forest ecological conservation and health restoration.The results showed that:(1)The wild fruit forests in Yili are mainly distributed in Guozigou,Daxigou,Mazigou,Dazigou,Daxigou,Awuzan,Kebuerqin Mountain,Small Leaf White Wax Reserve,Tuergen Valley,and Girgerang River Basin;The wild fruit forest was mainly distributed in the form of mixed tree species.In terms of spatial distribution,it is mainly distributed at an altitude of900m to 1600m,and the slope is 5 to 25 degrees.The slope direction is gentle and sharp.(2)From the 1960s to 2017,the area of four density grades of wild fruit forests continued to decrease,among which,the area of low and high density wild fruit forests decreased the most,while the area of middle and low density wild fruit forests decreased less.The total area of wild fruit forest decreased by 65216.3hm~2.It can be seen from the landscape transfer matrix that the wild fruit forest in Yili Valley mainly flows to grassland and cultivated land,and this transformation phenomenon is a one-way transfer.From 1960to 2017,the fragmentation degree of wild fruit forests showed an overall increasing trend.Among the four density grades of wild fruit forests,the low density wild fruit forests had the highest fragmentation degree,the most intense fragmentation degree and the highest marginal density,which indicated that the low density wild fruit forests were considered to be more affected.The fragmentation degree of middle and high density wild fruit forest is the lowest and relatively stable.Under the background of rapid economic development,it has certain influence on the integrity and concentrated distribution of wild fruit forests,leading to the fragmentation of wild fruit forests.Under the influence of the rapid development of agriculture and animal husbandry,the fragmentation of wild fruit forests is further intensified.As for the hot spot analysis of influencing factors,it can be seen that the radiation effect of agriculture and animal husbandry is stronger on the Northern Slope of Korbulqin Mountain,the Northern Slope of Narati Mountain,Turgen Gully,and the Girgrang River Basin,therefore,the change of wild fruit forests in these regions is the most drastic.(3)The results of CA-Markov simulation show that the regions with the highest survival risk are Turgen Valley,Daxigou,Xiaoxigou and the north slope of Narati Mountain,which is directly related to the local population expansion,agricultural and animal husbandry development and economic growth;The decrease of survival risk in the south of the Guergrang River Basin is closely related to the establishment of national protection area in the south. |
