典型草原7种植物的放牧退化敏感度的比较研究

研究了大针茅 羊草草原三个不同退化强度群落中7个植物种-大针茅、羊草、羽茅、糙隐子草、洽草、冷蒿、星毛委陵菜的地上生物量的差异及其季节变化特点.研究结果表明随着退化强度的增加,大针茅、羽茅地上生物量明显降低,糙隐子草、星毛委陵菜的地上生物量持续地增加,变化规律比较明显.根据距离系数和相对敏感度的特点,可把7种植物分为两种类型,一种类型包括羽茅、洽草、冷蒿、大针茅四种植物,当草原从无退化阶段发展到中度退化阶段时,它们的退化敏感度较大,其退化敏感度大小依次是:羽茅≥洽草>冷蒿>大针茅;可把它们作为草原发生中度退化的指示植物,其中羽茅、洽草具有相对较强的指示意义.另一类型包括羊草、星毛委陵菜、糙隐子草三种植物,当草原从中度退化阶段发展到重度退化阶段时,它们的退化敏感度较大,其敏感度大小依次是:羊草>星毛委陵菜>糙隐子草,它们可被作为草原从中度退化向重度退化发展的指示种,以羊草的指示价值最高.

A Comparative Study on Relative Sensibility of 7 Species to Different Grazing Degradation in the Typical Steppe

The difference and seasonal change characteristics of above-ground biomass for 7 species(Stipa grandis,Leymus chinensis,Achnatherum sibiricum,Cleistogenes squarrosa,Koeleria cristata,Artemisia frigida,Potentilla acaulis) were analysed in three different degraded communities from May to September in 2001.The result showed that the above-ground biomass of Stipa grandis,Achnatherum sibiricum decreased obviously but the biomass of Cleistogenes squarrosa,Potentilla acaulis continuously increased along with the increase of degraded degree. According to the Distance Index and Relative Susceptibility,the 7 species could be devided into two types.The first group included 4 species,their Relative Susceptibility was higher when the non- degraded community developed to the stage of moderately degraded community,the scale of Relative Susceptibility for the four species in proper order was:Achnatherum sibiricum> Koeleria cristata> Artemisia frigida> Stipa grandis,those plants could be used as indicator plants when the non- degraded community degraded to the moderately degraded community. The other group included 3 species,their Relative Susceptibility were higher when the moderately degraded community degraded to the heavily degraded community,the scale of Relative Susceptibility for those three species in proper order was:Leymus chinensis> Potentilla acaulis> Cleistogenes squarrosa,they could be regarded as indicator plants when the moderately degraded community degraded to the stage of the heavily degraded community.