不同补水保水方式下兰州北山区人工植被状况研究

在兰州市北山九洲台不同补水保水方式区（上水灌溉区和“三水”造林区），采用典型样地调查法，对比分析其人工植被的群落类型、结构、物种多样性及生长状况。结果表明：①“三水”造林区人工植被的主要类型为柠条林，群落结构较为单一，只有灌木和草本层，上水灌溉区人工植被的主要类型为侧柏＋刺槐＋柠条林和侧柏＋柠条林，群落结构较复杂，具有乔、灌、草三层结构；②不同补水保水方式区的物种多样性不同，上水灌溉区的物种丰富度较大，而“三水”造林区的Simpson指数较大；③种植时间相近的柠条及草本植物在上水灌溉区的生长状况均明显好于“三水”造林区；④不同的补水保水方式造成了区域水分条件的差异，进而影响了人工植被的群落类型、结构、物种多样性及植被生长状况。因此，在干旱区造林中，应根据当地水资源状况及立地条件，科学选择补水保水方式，并进行合理搭配。

Effects of Different Way of Water-replanishing and Water-conservation on Vegetation Status in Northern Mountain of Lanzhou

Using typical sampling method,the community type,structure,biodiversity and growth status were compared.The result indicated that the different way of water-replanishing and water-conservation drived the different artificial community formed.Constrained by water,in "three water"forestation area(water was conserved from rain,plastic muching and water injection to root for forestation),the main forest type is Caragana korshiskii Kom.;the dominated commuinty is Platycladus orientalis(L.) Franco Robinia pseudoacacia L. Caragana korshinkii Kom.and Platycladus orientalis(L.) Franco Caragana korshinkii Kom.in irrigated area.The community structure is simple in "three water" area(only shrub and herb).But the community structure is more complicated in irrigated area,which had tree,shrub and grass.In "three water"area,the species is richer but the Simpson index is lower than that in irrigated area.And the vegetation growth status was better in irrigated area than in"three water"area.The different way of water-replanishing and water-conservation change the water condition which differed the community structure and species diversity and vegetation growth status.Thus different way of water conservation and water replanishing must be chosen and collocated with the condition of local water and site in arid area.