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作 者 ：王炜, 刘钟龄, 郝敦元, 梁存柱

期 刊 ：植物生态学报 1996年 20卷 5期 页码：449-459

关键词：退化草原特征；恢复演替驱动力；

Keywords:Degenerated grassland, Property characteristics, Driving force for restoration,

摘 要 ：本项研究自1983年起在锡林河中游对放牧退化的冷蒿(Artemisia frigida)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(Leymus chinensis+Stipa grandis)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厂探讨。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．退化群落与其原生群落的种—生物量关系呈对数正态模式，其演替过渡阶段成为分割线段模式，也反映出群落资源分配格局与群落空间格局的关系。5．退化草原的显著特征是植被生产力下降，冷蒿群落的生物量下降到原生群落的30％～40％，家畜嗜食的植物种减少50％～70％总生产力不足原生群落的30％。6．退化群落在自然封育条件下能够迅速恢复的原因，可归结为植物在削除放牧干扰后的种群拓殖能力与群落资源(水分，矿质养分等)的剩余。群落资源条件是种群拓殖的物质基础，从而成为恢复演替的动力。

Abstract: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 1m2 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

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