基于草地退化指示植物大狼毒的植被指数研究

Vegetation Indices of Euphorbia jolkinii As An Indicator Plant of Grassland Degradation

为建立基于指示植物的滇西北地区草地退化遥感评价技术体系,将有毒植物大狼毒(Euphorbia jolkinii)作为草地退化的指示植物,筛选并构建了反映草地群落中大狼毒组分信息的植被指数。结果表明:部分特殊样地有可能放大GPS定位偏差对植被指数与地面调查指标相关性研究的不利影响,最好予以剔除。现有的植被指数与大狼毒调查指标的相关性略低于其与总体调查指标的相关性,不适合作为大狼毒的遥感监测指标。采用Landsat 5卫星第5波段影像校正后的植被指数与大狼毒调查指标的相关性增加,而与总体调查指标的相关性降低,在弱化样地总体群落信息、突出大狼毒组分信息方面GNDVIc表现最佳,较适用于草地群落中大狼毒组分的遥感监测。

In order to establish the remote sensing evaluation system of grassland degradation based on indi- cator plant in the northwest of Yunnan Province, Big Euphorbia （Euphorbia jolkinii） was used as an indi- cator plant of grassland degradation. Vegetation indices reflecting the information of Big Euphorbia in grassland communities were filtered and constructed. Results showed that some special plots which might amplify the negative effect of positioning deviation on the correlation between vegetation indices and ground survey indicators should be excluded. The existing vegetation indices had lower correlation with the survey indicators of Big Euphorbia compared with overall survey indicators, and were not suitable for the remote sensing monitoring of Big Euphorbia. The correlation of the vegetation indices corrected using the band 5th image of Landsat 5 satellite with the survey indicators of Big Euphorbia increased, whereas with the overall survey indicators of plots decreased. GNDVIc had the best performance in weakening the overall information of plots and highlighting the information of Big Euphorbia ingredient, was a more suit- able vegetation index to monitor the component of Big Euphorbia in grassland communities.