不同管理条件下永久性草地样方的生长型谱和多样性(英文)

相当一段时间以来,人们对于永久样方中植被所做工作主要集中于对其一定时间范围之中区系成分变化的研究.例如用不同的管理方法所产生效果的对比.根据植被中物种的多样性,本文将着重探讨在老的稳定草地群落之中的一系列样方生长型谱的变化情况.植被的结构由植物的生长型决定,而植被结构对于萌发过程和新个体的定居是极为重要的,因此与区系成分就密切相关.把注意力放在植物生长型、植被结构与成分上,将扩大我们对植物群落是怎样行使其功能这一问题的理解.按照Barkman(1979)的方法,我区分出了植被结构与植被质地,认为植被质地是关于不同形态要素的质量和数量组成,不考虑其排列情况,而植被结构是这些要素的空间(水平和垂直)的排列.本文运用在一石灰质的草地上永久样方中14—15年的研究.指出了植物种的多样性和不同生长型的显著性的关系,研究中采用了如下几种方法:放羊、(扌弃)荒、割草,而后两种处理方法又分别采用了施肥与不施肥的处理.从显花植物之中区分出了十个不同的生长型,且用种的估计盖度百分比所得的生长型谱与用地上植物量所测的生长型谱极相符合,某些生长型(高禾草、爬缘双子草植物和高灌木)的显著度与种的多样性下降显著相关,而另外一些生长型(丛生植物、花茎上无叶)的显著性并不表现出与种多样

GROWTH FORM SPECTRA AND SPECIES DIVERSITY IN PERMANENT GRASSLAND PLOTS WITH DIFFERENT MANAGEMENT

The relation between plant species diversity and dominance of different growth forms is presented in this paper, based on a 14-15 years period of research on experimental permanent plots in a calcareous grassland with several management regimes. Ten different growth forms of phanerogamic specios have been distinguished. Growth form spectra based on the estimated cover percentage of the species correspond fairly well with those based on the measured amount of above ground phytomass. Dominance of some growth forms is clearlr related to a decreasing species diversity, whereas dominance of another growth form shows no negative effect on species richness. The former phenomenon is met within abundant as well as in fertilized plots, the latter effect can be seen in the unfertilized plots. In the sheep crazed plots no species has become dominant. Dominance of different growth forms may cause an entirely different vertical vegetation structure, and hence, a different influence on species diversity, even if the above ground phyto-mass is almost equal.