兰州市九州台区不同海拔高度人工林群落物种多样性

通过对兰州市九州台区不同海拔人工林群落结构进行典型样地调查,分析了该林区3种海拔梯度人工林群落的物种多样性特征。结果表明,3种海拔梯度人工林中,中坡(海拔1 760～1 840m)物种多样性指数为最高,物种最丰富,恢复程度最好;3种海拔梯度人工林以上坡(1 900～1 970m)灌木层和草本层物种丰富度指数最小,下坡(1 590～1 730m)灌、草层物种丰富度最大;物种丰富度、种类组成和多样性表明,九州台区人工林草木层总体发育优于乔灌层;各梯度人工群落尚处于演替初期阶段,林下植被发育常以阳生性植物为主;对不同海拔人工林群落结构研究是兰州市南北两山生态绿化工程的延伸,该项研究对于兰州市南北两山植被恢复后的生物学效果评价具有重要意义。

Biodiversity of Plantation Communities Under Different Altitudes in Jiuzhoutai District of Lanzhou City

The structure characteristics of the communities under manmade forests were surveyed at three different attitudes in Jiuzhoutai District of Lanzhou City based on typical sampling strategy.The characteristics of species diversity were then analyzed based on the survey results.The results indicated that the communities on the midslope(altitude1 760-1 840 m) had the highest species diversity indices(DHJ),the most species,and the best recovery degree.The layers of shrub and herb on the upslope(1 900-1 970 m) showed the lowest richness index,while the layers of shrub and herb on the downslope(1 590-1 730 m) showed the highest.The development of herbaceous layer was apparently better than the layers of shrubs and woods on the north mount according to the richness index,the species composition and biodiversity.The succession of communities was still at their early stages at all the slope positions,as implied by the dominant sunny species under the woody layer.The research on the biodiversity of manmade ecosystem at different altitudes was the extension of eco-afforestation project carried out on the north and south mounts;the findings from this study is of great importance for evaluating the effectiveness of vegetation recovery and reconstruction on the north and south mounts.