民勤绿洲人工梭梭林群落结构及种群生态特征

Community Structure and Population Ecological Features of Planted Haloxylon ammodendron in Different Habitats in Minqin Oasis

采用野外样方调查方法,分别对生长于民勤绿洲盆地不同立地类型的人工梭梭群落内的物种重要值、多样性等生态特征进行分析,将其划分为3个类型:梭梭—一年生植物群聚、梭梭—一年生植物—灌木群聚和梭梭—灌木群落;分别分布于流动沙丘、半固定沙丘和固定沙地上,随着沙地固定程度的增加,人工梭梭群落由梭梭—一年生植物群聚(先锋群落,盖度23%、多样性指数0.26)演替到梭梭—一年生植物—灌木群聚(盖度30%、多样性指数0.34)再演替到梭梭—灌木群落(盖度40%,多样性指数0.60);在人工梭梭群落演替过程中,人工梭梭种群在不同沙地类型上生长状况不同,沿着流动沙地→半固定沙地→固定沙地为衰退型,这种衰退与土壤水分的含量有关。

The important values and the Shannon-Wiener indexes were analyzed based on carrying out a field in- vestigation on sample plots of planted Haloxylon ammodendron communities in different sandy habitats in Minqin Oasis. The planted H. ammodendron communities were classified into three types, i. e. , the H. ammodendron （ annu- al herbage） community, H. ammodendron （annual herbage with shrubs） community and H. ammodendron-shrub community, and these communities were distributed on mobile sand dune, semi-fixed sand dune and fixed sand dune respectively. With the increase of sand-fixed degree, the community succession was ranked from H. ammodendron community （annual herbage ,pioneer community with a coverage of 23% and Shannon-Wiener index of 0.26） to H. ammodendron （annual herbage with shrubs with a coverage of 30% and Shannon-Wiener index of 0.34）, and then to H. ammodendron-shrub community （with a coverage of 40% and Shannon-Wiener index of 0.60）. In the succes- sion, the growth of planted H. ammodendron populations in different habitats was different, a recession of planted H. ammodendron populations occurred from mobile sand dune to semi-fixed sand dune and then to fixed sand dune, and such recession was related to soil moisture content.