雅鲁藏布江中游河谷风沙化土地砂生槐群落结构特征  

Structural characteristics of Sophora moorcroftiana community on wind-sandy land in middle reaches of Yaluzangbu River

作　　者：杨兆平[1] 沈渭寿[1] 孙明[1] 孙俊[1] 李海东[1] 

机构地区：[1]国家环境保护部南京环境科学研究所,南京210042

出　　处：《应用生态学报》2011年第5期1121-1126,共6页Chinese Journal of Applied Ecology

基　　金：国家环保公益性行业科研专项(200809010;200909050)资助

摘　　要：基于样方调查和等级聚类分析,研究了雅鲁藏布江中游风沙化土地不同恢复演替阶段砂生槐群落的结构特征.结果表明:雅鲁藏布江中游风沙化土地植物群落可分为砂生槐群落、固沙草群落、砂生槐<固沙草群落、砂生槐-固沙草群落、藏沙蒿+砂生槐群落和砂生槐+藏沙蒿群落6种类型.自然恢复演替从流动沙丘上分布的砂生槐对流沙的初步固定开始,随后固沙草开始侵入群落,逐渐形成了砂生槐-固沙草群落.另一种演替途径开始于固沙草群落,砂生槐在演替过程中出现在固沙草群落中,最后亦达到砂生槐-固沙草群落阶段.在一些半固定沙地阶段,藏沙蒿开始侵入群落,形成砂生槐+藏沙蒿群落.雅鲁藏布江风沙化土地的顶极群落是以砂生槐为优势种的灌丛群落.随着坡度增加,砂生槐群落盖度和高度有降低的趋势.生物结皮对土壤的理化性质有一定的改善作用,结皮覆盖处土壤水分含量显著高于其他演替阶段的表层土壤水分含量.流动沙地砂生槐灌丛冠幅、株高和萌蘖枝数量最高,其次是固定沙地,半固定沙地最低.各阶段枯死枝数量说明固定沙地阶段以后砂生槐种群有衰退的趋势.Based on quadrat investigation and hierarchical cluster analysis,this paper studied the structural characteristics of Sophora moorcroftiana community at its different restoration succession stages on the wind-sandy land in middle reaches of Yaluzangbu River.The plant community on the wind-sandy land could be divided into 6 types,i.e.,S.moorcroftiana community,Orinus thoroldii community,S.moorcroftiana O.thoroldii community,S.moorcroftiana-O.thoroldii community,Artemisia weiibyii ＋ S.moorcroftiana community,and S.moorcroftiana ＋ A.weiibyii community.The restoration succession began with the sand-fixing S.moorcroftiana distributed on moving dune,followed by O.thoroldii invasion,and then,S.moorcroftiana-O.thoroldii community formed gradually.Another restoration succession approach began with O.thoroldii community,S.moorcroftiana occurred then,and finally,S.moorcroftiana-O.thoroldii community formed.On semi-fixed dune,A.weiibyi could invade the community,and S.moorcroftiana ＋ A.weiibyi community formed.The climax community on the wind-sandy land was the shrub community dominated by S.moorcroftiana.With increasing slope grade,the coverage and height of S.moorcroftiana community tended to decrease.Biological crust had definite improvement effect on the soil physical and chemical properties.At the places with biological crust,surface soil water content was significantly higher,compared with that at the places with other restoration succession stages of S.moorcroftiana community.The crown diameter,plant height,and the sprouting branch number of S.moorcroftiana community were the highest on moving dune,followed by on fixed dune,and on semi-fixed dune.The dead branch number at different restoration succession stages indicated that S.moorcroftiana population had a declining trend after the sand was fixed.

关 键 词：雅鲁藏布江中游 风沙化土地 恢复演替 砂生槐 群落结构 

分 类 号：Q948[生物学—植物学]