长白山毛赤杨和白桦/沼泽交错带植物多样性分布格局

Distribution Patterns of Plant Biodiversity on the Alnus hirsuta and Betula platyphylla-swamps Ecotones in Changbai Mountains

采用样带网格调查方法和香农—威纳多样性指数分析方法,研究长白山毛赤杨、白桦/沼泽交错带和干扰白桦/沼泽交错带植物多样性水平分布和垂直分布格局。结果表明:①毛赤杨、白桦/沼泽交错群落植物多样性随着交错区环境梯度变化呈现出凸型水平分布格局,其植物多样性指数为相应地段森林群落的1.5倍,沼泽群落的2～3倍。干扰白桦/沼泽交错群落植物多样性随着交错区环境梯度变化呈现出凹型水平分布格局,其植物多样性指数仅相当于相应地段沼泽群落或森林群落的80%左右,仅为毛赤杨、白桦/沼泽交错群落的70%;②毛赤杨、白桦/沼泽交错群落植物多样性呈现“金字塔型”垂直分布格局,其垂直分布格局是草本层(5):灌木层(3):乔木层(1)。而干扰白桦/沼泽交错群落植物多样性垂直分布格局为草本层(5):灌木层(0.4):乔木层(1),并未呈现典型“金字塔型”分布。因此,人为经营活动不仅降低了森林/沼泽交错带植物多样性水平,也改变了其分布格局。

The distribution patterns of plant biodiversity were studied in the two kinds of ecoto-nes between forests and swamps in the Changbai Mountains,by using transect and Shannon-Wiener index methods,in order to reveal the distribution patterns of plant biodiversity along the moistened environmental gradients or among vertical layers of communities in the Alnus hirsuta,Betula platyphylla-swamp ecotone or Betula platyphylla-swamp econtone disturbed by human activities.The results showed that:① The horizontal distribution patterns of plant biodiversity ap-pears a protruding shape along the A.hirsuta,B.platyphylla-swamp ecotones.Plant biodiversity of this kind of ecotone community is 2～3 times that of nearly swamp community, and 1.5 times that of forest community.On the contrary,it presents a concave shape,and plant biodiversity is only 80% that of nearly swamp or forest community in the B.platyphylla-swamp ecotones disturbed by human activities.②The vertical distribution pattern of plant diversity presents a 'pyramid shape'in A.hirsuta,B.platyphylla-swamp ecotones,the ratio of which is tree layer:shrub layer:herbage layer being 1:3:5.In contrast,no'pyramid shape'occurs in B.platyphylla-swamp ecotones disturbed by human activities,the ratio of which is tree layer:shrub layer:herbage layer being 1:0.4:5.So human induced disturbanc has great influence on distribution patterns of plant diversity in the B.platyphylla-swamp ecotones.