甘肃省白银地区草地资源特征与草地生态变化

Characteristics of grassland and ecological change of vegetations in Baiyin Region of Gansu Province

天然草地的组成类型及退化特征,对草地资源的合理利用和退化草地生态的恢复治理具有重要的生态学意义．对白银地区天然草地资源组成、草地类型结构以及退化草地植被特征进行了系统调查与分析,研究了不同退化演替时期草地植物生态型、生产力的构成变化规律．随草地退化程度的加剧,从初期到后期,高位芽植物最先消失,草地植物群落物种数和优势种密度急剧下降,群落盖度、生物量比、鲜草产量与可食草产量百分数均呈逐渐下降趋势．提出了天然草地永续利用的对策．

The constitution and degrading character of natural grassland are of very important ecological significance for exploiting the natural grassland rationally and for restoration of the degrading grassland ecosystem. In this paper, we have researched into and analyzed the constitution of resources, types and structures on the degraded grassland in Baiyin Region. We have also studied the varying regularity of ecological types and output of vegetation in different degrading periods on natural grassland. With the severity of degeneration of grassland, from the initial stage to a latter period, the plant in perch-bud first disappeared, the plant amount of vegetation Community and the density of predominant plant declined sharply. The convergence, biomass and the proportion of the production of fresh grass to edible grass have also declined rapidly. We have also put forward some countermeasures, which can help ensure the grassland and its stockbreeding in a sustainable way.