北方农牧交错带不同植被保护及恢复措施物种多样性研究

为研究不同生境类型及不同植被恢复方式植物群落结构特征及物种多样性,本文以位于我国西北农牧交错带的宁夏盐池为研究对象,根据不同植被恢复及保护措施特点,在宁夏盐池布设典型样地。样地类型分为:天然草地、退耕还草地、撂荒地、湿地、人工封育草地、流沙地等6种类型。植被调查采用样线和样方相结合的方法,内容包括:植物名称、株数、盖度、高度、生物量(鲜质量)等。运用生态统计学原理,结合BiodiversityPro、MicrocalOrigin等生态学统计软件对不同样地类型植物进行聚类、多样性指数计量等处理、分析。聚类分析表明:不同植被保护及恢复措施下,植物组成、群落结构、主要建群种等都表现出不同特点,不同样地具有各自不同的优势群落、主要建群种等;多样性指数计量结果表明:不同样地间由于生境类型、植被保护及恢复措施等不同造成样地间物种多样性的差异,湿地由于充足的土壤水分条件,无论是丰富度指数还是综合多样性指数都远高于其他样地类型,综合多样性指数D、H分别为12.783、2.915。此外,退耕还草地和天然草地多样性指数也较高,尤其是退耕还草地,D、H分别为11.514和2.696,是农牧交错带一种较为合理的植被恢复措施;多样性较低的是人工封育草地,D、H分别为2.599、1.576。造成人工封育草地物种多样性较低的主要因素一是随着封育时间的延长,优势种的优势地位不断加强、种间竞争等导致部分物种的消失等原因;二是随着封育时间的增加,土壤结皮加厚,水分入渗率和利用率降低从而导致植物群落衰退。

Study on species diversity of different measures of vegetation protection and restoration in the farming-pastoral ecotones in the north of China

In order to study the plant communities characteristics and species diversity of different measures of vegetation protection and restoration, Yanchi of Ningxia Hui Autonomous Region were selected as representative sample-plot. The types of sample-plots in Yanchi were divided as nature grassland, rehabilitated fields, abandoned land, wetland, fenced taming grassland and shifting sand. The quadrat method and sample line approaches were used to investigate plant growth status. The items investigated include plant name, species, individual plant number, coverage, height, aerial biomass (fresh weight) etc. Coped with ecological statistic principles, data were processed and analyzed by the ecological statistic software like Biodiversity Pro, Microcal Origin etc. Cluster analysis results showed that the plant composition, community structure, main constructive species take different characteristic in different types of sample plots. Different sample-plots have different dominant communities and constructive species etc. The species diversity indexes studies showed that the species diversity indexes were significant difference because of different vegetation protection and restoration measures. Whether the richness index R, the species amount and abundances indexes or the comprehensive diversity in- dexes D, H of wetland were higher than that of other types of sample-plots. Its comprehensive diversity indexes D and H were 12.783 and 2.915. Moreover, the species diversity indexes of rehabilitated fields and nature grassland were very high, especially the rehabilitated fields to grassland was an effective measure of vegetation restoration; its comprehensive diversity indexes D and H were 11.514 and 2.696. The species diversity indexes of fenced taming grassland were lower than other types of sample-plots; its compre- hensive diversity indexes D and H were 2.599 and 1.576. The reasons of which were, in one hand, interspecies competition leading to some rare species vanished; on other hand, as time increased, the soil crust increased and thicken, which leaded plant community declined.