玛曲高寒草甸放牧强度的遥感监测

Monitoring of grazing intensity in Maqu alpine meadow by remote sensing

为给玛曲县高寒草甸草-畜平衡和草地资源的可持续利用提供科学依据,本研究利用遥感技术,结合2016年地面实测数据和同时期的MODIS影像资料,分别建立了研究区草地地上生物量和植被指数(NDVI)、相对放牧强度间的回归模型以及不同相对放牧强度和NDVI值之间的幂回归模型。结果表明,6-9月调查点NDVI和地上生物量间存在较好的相关性,即随着NDVI值的增加生物量呈上升趋势,且9月份的拟合(R2=0.510 2)达到了极显著水平;实测地上生物量和相对放牧强度之间有很好的拟合关系(R2=0.965 1),随着放牧强度的增加地上生物量呈下降趋势;相对放牧强度和植被指数间相关性较好(R2=0.631),即随着NDVI值的变小,相对放牧强度逐渐增强,当相对放牧强度增强到一定程度时,NDVI对其响应不灵敏。

To provide a scientific basis for the sustainable utilization of grassland resources and grass-livestock balance in the Maqu alpine meadow,this study used remote sensing technology combined with field-measured data and MODIS image data in the same period in 2016.Regression models of aboveground biomass and vegetation index（NDVI）with relative grazing intensity were established individually in the study area,and a power regression model between different relative grazing intensities and NDVI was additionally established.The result showed that with increase in NDVI,aboveground biomass increased in June,July,August,and September.Ground biomass and relative grazing intensity showed optimum significant negative correlation（R2=0.965 1）,which was a power curvilinear regression.Relative grazing intensity and vegetation index showed good correlation（R2=0.631）;with decrease in NDVI,relative grazing intensity increased gradually.When relative grazing intensity increased to a certain extent,NDVI was not sensitive to its response.