摘要
本项研究自１９８３年起在锡林河中游对放牧退化的冷蒿（Ａｒｔｅｍｉｓｉａｆｒｉｇｉｄａ）占优势的草原群落变型进行封育恢复实验与长期监测。每年在植物生长季以１５天为间隔进行取样测定，即每年测定９期，每期做１０或２０个１ｍ×１ｍ的样方。测定项目包括：群落中各植物种群的地上现存生物量、密度、高度、花（果）枝数等。还采用改进的样方方差法监测植物种群空间分布格局的动态。并同时在保护良好的羊草＋大针茅（Ｌｅｙｍｕｓｃｈｉｎｅｎｓｉｓ＋Ｓｔｉｐａｇｒａｎｄｉｓ）群落中进行测定取得完全对应的数据，作为对照系列。以上两种群落的土壤水分与养分动态的长期监测由本站土壤组承担。根据连续十二年监测数据的分析，对退化草原群落的性质与特征提出以下的认识，并对退化草原恢复演替的驱动因素进行了探讨。１．草原退化演替阶段是与一定强度的放牧压力保持平衡而相对稳定的群落变形，退化阶段取决于牧压强度与持续的年代。２．当群落退化到冷蒿为主要优势种的阶段时，与原生群落的种类组成相比，只发生一定的数量消长变化，对群落的物种丰富度影响不大。３．退化群落植物种群空间格局的均匀性较高，随着恢复演替的进展，因一些种群斑块增大而使空间不均匀性增强。４．退化群落与其原?
A grazing-induced degenerated Artemisia frigida community has been monitored till 1993 since it was fenced in 1983 in the middle reaches of the Xilin River. The vegetation was measured by 10～20 quadrats of lm￣2 once per 15 days during the plant growing season from May to September each year. The species standing crops, density,height, water content, and their flowering stem number were recorded. The similar monitoring were simultaneously conducted in the well protected communities dominated by Leymus chinensis and Stipa grandis. The dynamics of spatial distribution pattern of plant population has also been monitored with improved method of quadrat variance. Based on a comparative analysis of these data, the community features were summarised and the driving force for restoration was discussed. The results are as follows: 1. The degenerated Artemisia frigida community is in a stable state corresponding to a certain grazing intensity. Degeneration degree depend on the grazing intensity. 2. The species composition of the degenerated A. frigida community has no significant difference from that of primary plant community dominated by L. chinensis. The grazing disturbance has a big effects on the proportion of plant population in community, but no much effects on the species richness for the succession series between A. frigida and L. chinensis communities. 3. The spatial hetterogeneity is low in degenerated community, and will increase with the restoring succession due to the patches of some populations'expansion. 4. The species-biomass relationships in degenerated community and in primary community fits to a log-normal distribution model. The restoration succession fits to a broken-stick distribution model. 5. A significant character of the degenerated grassland is the low productivity. The productivity is only 1/3 of the primary community, and palatable forage proportion is only 50% -70% of the primary community, so the usable productivity decreased to only 30% of that of primary community. 6. The plant colonising ability and the relative surplus resource in the degenerated community is the driving force for its restoration
出处
《植物生态学报》
CSCD
北大核心
1996年第5期449-459,共11页
Chinese Journal of Plant Ecology
基金
国家自然科学基金
关键词
退化草原
群落
恢复演替
草原生态
内蒙古
Degenerated grassland
Property characteristics
Driving force for restoration
