长白山溪流河岸带森林木本植物多样性沿海拔梯度分布规律

采用样带网格调查方法和α、β多样性指数分析方法,研究了长白山河岸带原始林和次生林群落木本植物多样性沿海拔梯度分布规律及其对采伐干扰的响应.结果表明：不同海拔区域河岸带原始林群落均由11～13个树种组成,其在群落中的地位随海拔升高而发生变化,阔叶树种优势地位逐步被针叶树种所取代,采伐干扰不仅改变了群落树种丰富度及其在群落中的地位,而且使针叶树种取代阔叶树种的趋势有所增强;河岸带原始林群落物种多样性沿海拔梯度呈现出中、低海拔区域相对较高且比较恒定(2.454～2.544),高海拔区域(2.250)下降的分布规律,采伐干扰改变了其沿海拔梯度分布格局(波动型),加大了不同海拔区域群落间的波动性(2.174～2.692);河岸带原始林群落树种沿海拔梯度的变动速率相对较低(1.5～3.5),且群落相似性较高(0.85～0.94),采伐干扰使次生林群落树种沿海拔梯度的变动幅度增大(0.5～6.0),群落相似性下降(0.68～0.91),但次生林群落沿海拔梯度分布仍具有较高连续性.

Distribution patterns of woody plant diversity in stream riparian forests along an altitudinal gradient in Changbai Mountains.

By setting up sample transects and using alpha and beta diversity indices, this paper studied the woody plant diversity and its responses to cutting in the stream riparian primeval and secondary forests along an altitudinal gradient in Changbai Mountains. The results showed that all of the primeval forest communities distributed at different altitudes were composed of 11-13 tree species, but the importance of these tree species varied with altitude. Conifer species gradually took the place of broad-leaved tree species along the altitudinal gradient. Cutting not only made the tree species richness and importance changed, but also further strengthened the trend of tree species replacement. The Shannon-Wiener diversity index of the woody plants in primeval forests varied from 2.454 to 2.544 at the altitudes of 750-800 m, 800-850 m and 850-900 m, which was higher than that (2.250) at the altitude of 900-950 m. Cutting changed this distribution pattern, and enlarged the fluctuation (2.174-2.692) among the communities at different altitudes. The Cody index of primeval forest communities along the altitudinal gradient varied from 1.5 to 3.5, and the community similarity coefficient varied from 0.85 to 0.94. As for the secondary forest communities, their Cody index and community similarity coefficient changed from 0.5 to 6.0 and from 0.68 to 0.91, respectively, indicating that cutting increased the tree species replacement rate, and reduced the community similarity. However, a higher continuity still existed in the secondary forest communities.