放牧对贝加尔针茅草原植物个体和群落生物量分配的影响

通过对贝加尔针茅草原的调查研究,分析了严重放牧样地、中度放牧样地、天然草地以及放牧后围封样地的群落水平与个体水平根冠比的差异,以及各构件生物量分配比例,得出以下结论：1）严重放牧样地地上、地下生物量显著小于天然草地,过度放牧后植物的根冠比显著高于天然草地;2）中度放牧样地的地下生物量与天然草地相差不大,群落水平的地下生物量最高;3）放牧样地受到破坏后围封,个体植株较天然草地小,但生物量略高于天然草地.

THE EFFECTS OF GRAZING ON INDIVIDUAL-LEVEL AND COMMUNITY-LEVEL BIOMASS ALLOCATION IN THE STIPA BAICALENSIS STEPPE

This paper analyzed the differences in root-shoot ratio both at the individual and community levels,and biomass allocation ratio of each component in the Stipa baicalensis steppe.It was found that: 1) Above-ground and below-ground biomass of severely grazed plots was significantly less than those in natural grassland,the root-shoot ratio was significantly higher than in natural grassland.Therefore frequent grazing led to grassland degradation.2) At the community level,above-ground biomass of moderately grazed plots decreased in comparison with natural grassland,but below-ground biomass showed little difference from natural grassland;moderately grazed plots showed the highest level of below-ground biomass among severely grazed plots,enclosed plots or natural grassland.3) In enclosed grass plots which were severely grazed in the past,morphology and physical size of individual plants tended to be smaller than in natural turf,yet their biomass was slightly higher than natural grassland.