中文摘要：

微地形是影响植被分布格局及多样性的重要因素。在元谋干热河谷冲沟区采集了1236组“土壤一坡度一坡向一植被盖度一物种多样性”数据，运用统计学方法研究了坡度和坡向这两个地形因子对干热河谷植被盖度及其多样性的影响。结果表明：在元谋干热河谷冲沟区，植被盖度呈现出随坡度增大而减小的趋势，变性土区域活跃性冲沟坡面上有无植被生长的临界坡度是50°，而燥红土区域稳定性冲沟的临界坡度为65°；受人类活动影响强烈的沟坡区植被生长的临界坡度是45°，影响较轻微的近自然状态沟坡区的临界坡度是65°；植被盖度分布和植被种类的优势方向同为东北向，平均盖度为40％，西北向为28％，西南为20％，东南为21％；植被种类东北向平均为1．8，西北向为1．4．西南向为1．0，东南向为0．5。研究元谋干热河谷典型立地条件下植被对冲沟微地形条件的响应，可以为本区生态恢复提供科学指导。

英文摘要：

Micro-topography is an important factor affecting the distribution and diversity of vegetation, especially in the Yuanmou dry-hot valley. By collecting 1 236 groups data of the soil-slope-aspect-vegetation coverage-species diversity in the gullied area, combined with statistical methods to study the influence of the two topographic factors- slope and aspect functions on the diversity and vegetation coverage of dry-hot valley. It is showed that in the dry-hot valley gully area, vegetation coverage has a decreasing trend with an increase of slope. The critical slope gradient judging whether there exists the vegetation growth or the vertex soils regional activities to jump on the gully slope is 50~, while the critical slope gradient of the regional stability of dry red gullies is 65~ ; by the strong influence of hu- man activities, the critical slope gradient of gully vegetation growth is 45~; the critical slope gradient of the gully area which is relatively minor impacted is 65~ ; the dominant direction of the vegetation cover distribution and vege- tation types is northeast, with an average coverage of 40%, the northwest is 28%, Southwest 20%, Southeast 21% ; the vegetation types average of northeast is 1.8, northwest 1.4, Southwest 1.0, southeast 0.5. Researching on the response of the dry-hot valley vegetation to the gully micro-terrain environment in the typical site conditions could provides scientific guidance for the ecological restoration.