Abstract: The reflectance spectra of degraded Seriphidium transiliense desert grassland at different stages were measured in the Tianshan Mountains of Xinjiang using a portable spectrometer SVC HR-768. The plant community of Seriphidium transiliense desert grassland, was composed of Seriphidium transiliense(decreasing species), Petrosimonia sibirica (increasing species) and Polygonum aviculare (invasive species). Results showed that the spectral reflectivity observed in the near-infrared band was ordered as bare soil >Polygonum aviculare >Seriphidium transiliense>Petrosimonia sibirica. The reflectance characteristic of the plant community was little affected by the spectral reflectivity of Polygonum aviculare, whereas the reflectance characteristic of the plant community was mainly affected by the spectral reflectivity of Seriphidium transiliense and Petrosimonia sibirica. The reflectance characteristic was positively correlated to the importance value of dominant species. The spectral reflectivity of moderately degraded grassland observed inside fence was greater than outside fence, whereas the spectral reflectivity of heavily and extremely degraded grassland outside fence was greater than inside fence.

Key words: Seriphidium transiliense, Desert grassland, Hyperspectral, Grassland degradation, Spectral characteristics

摘要： 利用SVC HR-768 便携式光谱仪测定围栏内、外不同退化梯度伊犁绢蒿（Seriphidium transiliense）荒漠草地植物群落的光谱反射率，以及该类草地退化过程中的优势种伊犁绢蒿（减少种）、叉毛蓬（Petrosimonia sibirica）（增加种）、萹蓄（Polygonum aviculare）（侵入种）和裸地的光谱反射率，为实现伊犁绢蒿荒漠草地的高光谱遥感监测奠定基础。结果表明：在近红外波段，特征种与裸地的光谱反射率为裸地>萹蓄>伊犁绢蒿>叉毛蓬。萹蓄光谱反射率对退化草地植物群落的反射特征影响很小。退化草地植物群落冠层光谱反射率主要受伊犁绢蒿和叉毛蓬反射特征的影响，与优势种重要值成正相关关系，中度退化草地植物群落光谱反射率为围栏内>围栏外；重度和极度退化草地植物群落光谱反射率为围栏内<围栏外。

关键词: 伊犁绢蒿, 荒漠草地, 高光谱, 草地退化, 光谱特征