党河源区土地利用变化及其生态环境效应

Land use change and ecological environment effect of Danghe River source region

土地利用变化影响着生态系统的结构和功能,评估土地利用变化引起的生态效应可为区域生态保护提供依据。以党河源区为研究对象,基于1987、1994、2000、2006、2011和2017年Landsat遥感影像,采用遥感生态指数(RSEI)和植物群落学调查方法,分析了土地利用变化及其生态环境效应的影响因素。结果表明:1987—2017年,党河源区天然牧草地、沼泽地和裸岩石砾地呈减少趋势,沼泽草地、河流水面、沙地和冰川及永久积雪呈增加趋势;生态等级为优和良等级面积增长了14.26%,差和较差等级面积减少了27.9%,RSEI从1987年的0.48上升为2017年的0.57;天然牧草地、沼泽草地和沼泽地RSEI的6年均值高于沙地和裸岩石砾地RSEI的6年均值;天然牧草地、沼泽草地和沙地RSEI值总体呈上升趋势,沼泽地RSEI值总体下降,裸岩石砾地RSEI值没有明显的变化;沼泽草地RSEI值与年降水量呈极显著正相关(P<0.01),天然牧草地、沼泽地RSEI值与年降水量呈显著相关(P<0.05),沙地和裸岩石砾地RSEI值与年降水量、年均温和牲畜存栏量相关关系不显著(P>0.05)。气候暖湿化和社会经济因素叠加作用促进了景观类型的演变,改善了党河源区的生态环境质量。

Land use change affects ecosystem structure and function.Evaluating the ecological environment effect of land use change can provide a basis for regional ecological protection.We analyzed the land use change,ecological environmental effects,and influencing factors of Danghe River source region,with Landsat remote sensing images in 1987,1994,2000,2006,2011 and 2017 as the main data source,using the remote sensing ecological index(RSEI)and plant community survey methods.The results showed that from 1987 to 2017,the areas of natural pasture,marshland,and bare rock gravel land in Danghe River source region showed a decreasing trend,while the areas of marsh grassland,river surface,sandy land,glaciers and permanent snow exhibited an increasing trend.The area with excellent and good ecological grades increased by 14.26%,while the area with poor and inferior ecological grades decreased by 27.9%.The RSEI increased from 0.48 in 1987 to 0.57 in 2017.The 6-year average value of RSEI in natural pasture,marsh grassland,and marsh was higher than that in sandy land and bare rock gravel land.The RSEI value of natural pasture,marsh grassland,and sandy land showed an overall upward trend,while that of marsh showed an overall downward trend,and that of bare rock gravel land had no obvious trend.There was a significant positive correlation between precipitation and the RSEI value of marsh grassland,natural pasture,and marsh land(all P<0.05).There was no significant correlation between RSEI value of sandy land,bare rock gravel land and annual precipitation,mean annual temperature,livestock inventory(P>0.05).The superposition of climate warming,humidification and socio-economic factors promoted the evolution of landscape types and improved the quality of ecological environment in the Danghe River source region.