关键词: 林隙, 面向对象, 高空间分辨率, eCognition, QuickBird, 支持向量机

Abstract: In this study, ten desert species including three lifeforms from Gurbantunggut Desert were selected to study the effects of different snow covers on seed germination. Three kinds of snow cover treatments were settled, i.e. snow doubling, natural snow and snow removal. Based on the results from indoor experiments, the seed germination types could be divided into four types, including high germination percentage with rapid germination rate, high germination percentage with slow germination rate, low germination percentage with rapid germination rate, and low germination percentage with slow germination rate. The treatments of double snow cover had positive or neutral effects on seed germination, while snow removal showed negative or neutral effects. After indoor regermination of those seeds which did not germinate in field sites, we found that snow cover had positive, neutral or negative effects on total germination percentages. Our results indicated that the germination of seeds from desert ecosystems had diverse germination types, which were related to the plant growth environment. The snow cover affected plant presence by changing the field or total germination percentages. Different species in the desert ecosystems evolved into different response strategies under changing environments (i.e. snow cover), most of which were not lifeform depended. The diversity of seed germination responses resulted from longterm evolution, being beneficial for the plant community to keep its structure and function stability.

Key words: object-oriented, forest gap, high spatial resolution, QuickBird, SVM, eCognition.