摘要
针对退化草地恢复与合理利用问题,选取生长季围封调制干草,其他时间轻度放牧利用的草地为研究对象,同时选取自由放牧草地为对照,进行不同围封年限群落结构及植物多样性的比较研究。结果表明,重度退化草地采用生长季围封措施后,群落生产力与物种多样性增加,群落结构和各物种的优势地位发生较大改变。随围封年限的延长,群落盖度与密度增加,到14年达最大,之后降低,高度和产量持续增加,围封25年达最大。草地由星毛委陵菜+冷蒿+克氏针茅演替为羊草+糙隐子草+麻花头。经5年围封,物种的丰富度、均匀度和多样性增加。随围封年限的延长,物种丰富度继续增加,到围封14年达最大,但由于围封14年后形成以羊草为单优势种的群落,物种均匀度及多样性降低。之后,随围封年限的继续延长,群落逐步趋于稳定,均匀度和多样性增加。群落相似性分析证明,采用生长季围封措施后,围封样地与未围封对照间的相似性降低,表明围封在改变群落的环境条件上也具有较好的效果。生长季围封调制干草,其他时间轻度放牧利用的管理方式可保证退化草地在一定程度上得到恢复,综合考虑群落结构、产量及物种多样性,认为14年是较适宜的围封年限。
To investigate the restoration process and reasonable utilization of degraded grassland; we chose as research objects natural grasslands which were exclosed during the growing season for hay production then sub jected to light grazing for the rest of the year. Continuous grazing land was used as a control. Comparative research on the influence of different exclosure years on the community structure and species diversity was carried out. The plant species and diversity of degraded grassland increased and the community structure and dominance of species changed greatly after seasonal exclosure. With increased periods of exclosure, coverage and density reached a maximum at year 14 then declined. Community yield and height continued to increase up to year 25. The community changed from Potentilla acaulis ＋ Artemisia frigidao＋ Stipa krylovii to Leymus chinensis＋Cleistogenes squarrosa q-Serratula centauroides. After 5 years of exclosure, the species richness, evenness and diversity increased. With increased periods of exclosure, the species richness increased continuously and reached its highest after year 14, but the community was mainly dominated by L. chinensis and the species evenness and diversity decreased. Along with the increase of exclosure year, the community gradually stabilized, the species evenness and diversity increased. The analysis of community similarity showed that the similarity between the exclosed sites and the control decreased, which showed that seasonal exclosure had a great impact on changing the environment of the community. We concluded that growing season exclosure for hay production followed by grazing through the rest of the year enabled the grassland to recover to some extent. After comprehensive consideration of the community structure, yield and species diversity, we consider that 14 years of seasonal exelosure appears a reasonable compromise.
出处
《草业学报》
CSCD
2008年第6期1-8,共8页
Acta Prataculturae Sinica
基金
国家重点基础研究"973"项目(2007CB106800)
中澳合作项目(AS2/2001/094)资助
关键词
典型草原
围封年限
群落结构
物种多样性
typical steppe
growing season exelosure
community structure
species diversity
