玛曲高寒草甸放牧强度的遥感监测

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。

Monitoring of grazing intensity in Maqu alpine meadow by remote sensing

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 vegeta-tion 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 re-sult showed that with increase in NDVI,aboveground biomass increased in June,July,August,and Septem-ber.Ground biomass and relative grazing intensity showed optimum significant negative correlation(R2=0.9 6 5 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 rel-ative grazing intensity increased to a certain extent,NDVI was not sensitive to its response.