昆仑山前山带植物群落调查及相似性初步研究

Investigation of Vegetation on Shallow Mountain Area of Northern Slope in Middle Section of Kunlun Mountain

对塔克拉玛干沙漠南缘，昆仑山北坡前山带的荒漠植物群落进行调查。结果显示：（1）在调查区域内发现21种植物，参与建群种15种，其他6种为偶见种。21种植物分属于10科20属，其中菊科（Compositae）和藜科（chenopodiaceae）植物13种；研究区5种植物群落的优势种分别为塔里木沙拐枣（Calligonum roborovskii）、琵琶柴（Reaumuria songarica）、河西苣（Hexinia polydichotoma）、蒿类植物（昆仑蒿Artemisia nanschanica＋昆仑绢蒿Seriphidiumkorovinii）与驼绒藜（Ceratoides latens）。（2）植物群落沿海拔高度变化地带性更替明显，低山砾质壤土母质上为塔里木沙拐枣和琵琶柴群落，集中分布范围分别为22002300m和2250～2400m，中部沙质土壤母质上为蒿类植物和河西苣群落，蒿类植物群落分布于海拔24002500m，河西苣群落集中于2500m高大沙丘丘间低地；驼绒藜群落在砾质土壤和沙质土壤母质上均有分布，海拔范围在2380～280013m。（3）群落结构简单，整体盖度小于10％，物种密度为4～13株（丛）／m^2，灌木层优势种单一，密度很小（1．2株（丛）／m^2），草本层冠幅水平低，盖度小（小于5％）；群落间高度、盖度、密度存在不同程度差异，物种丰富度指数（dm“）和生物多样性指数（D、H′、Jvw，Jgi）差异并不明显，总体处于较低水平。（4）群落盖度、密度、高度和物种数随海拔高度变化趋势不同，生物多样性指数随着海拔高度增加呈增加趋势；群落相似性比较显示，低海拔地区植物群落间的相似性高于高海拔地区。

The research was conducted in shallow mountain area of northern slope of Kunlun Mountain. Vegetation in this area typically belongs to arid and semi-arid ecosystem, composition and structure of communities are simple. Dominate species in five communities are Calligonurn roborovskii ,Reaumuria songarica, Hexinia pol ydichotoma , Artemisia nanschanica ＋ Seriphidium korovinii , Ceratoides latens. Calligohum roborovskii community and Reaumuria songarica community distributed on gravelly loam at low altitude,altitude distribution are 2 200～2 300 m and 2 250～2 400 m,Hexinia polydichotoma community and Arternisia nanschanica ＋ Seriphidiurn korovinii community distributed on sandy loam, altitude distribution are 2 400～2 500 m and 2 500 m,Ceratoides ＆tens community distributed both on gravelly loam and sandy loam,altitude distribution are 2 380～42 800 m. Plant species there were sparse,amount to 21 in all,38% of them are Chenopodiaceae and Compositae. Coverage of communities are lower than 10%,species density of communities are about 4～ 13/m2. Different levels of differences in coverage, height and density exist in coummunities investigated. However, the richness index （dMA） and the species diversity （D, H′, Jvw, Jgi ） are low with no significant differences among plant communities at 5 % or 1% level. Species diversity values increased along altitude elevation, the changes of coverage, height and density of communities along altitude elevation are not regular. Comparing the similarity coefficient, it is higher among communities at low altitude region than that of communities at high altitude region.