放牧干扰对典型草原植被光谱及蝗虫密度的影响

为研究内蒙古典型草原不同放牧强度植被反射光谱与植被参数和蝗虫密度的关系,使用地物波谱仪于2015年和2016年对5个放牧梯度,共20hm~2样地进行调查研究。结果表明,不同放牧强度植被地上总生物量与归一化植被指数(NDVI)关系为y=0.034 8+0.002 9x(R~2=0.645 5,P=0.000 2),蝗虫密度与NDVI线性关系为y=0.067+0.013x(R~2=0.415,P=0.006)。对其进行冗余分析(RDA)发现,植被地上总生物量、植物高度、糙隐子草生物量是蝗虫数量和NDVI变化的主要影响因子,其中植被地上总生物量是显著性影响因子(P=0.001)。在不同放牧强度下蝗虫密度与草地NDVI显著相关(P0.05),随NDVI增大而增多。本文研究结果为进一步开展放牧区蝗灾遥感监测和科学合理地利用草地资源奠定了基础。

The effect of different grazing intensities on hyperspectral remote sensing and locust abundance in typical steppe

To study the correlation between the normalized difference vegetation index (NDVI) of typical steppe and above-ground biomass and locust abundance in the Inner Mongolia grasslands with different grazing intensities, the reflectance spectra and above-ground biomass were measured by spectrometer in five different grazing treatments. The results indicated that the models of NDVI and above-ground biomass with different grazing intensities were correlated significantly: y=0.034 8+0.002 9x (R2=0.645 5, P=0.000 2), and locust abundance was y=0.067+0.013x (R2=0.415, P=0.006). The effects of grazing intensities on the abundance of locust and plant parameters with NDVI were examined with redundancy analysis (RDA). The results showed that the above-ground biomass, plant height and Cleistogenes squarrosa biomass were the main factors of locust abundance and NDVI, among which the significant factors was above-ground biomass (P=0.001). There was a significant positive relationship between NDVI and the abundance of locust. Above all, we can provide a theoretical basis for remote sensing monitoring of locust plague in grazing regions, and scientific and rational use of grassland resources.