不同围封年限对藏北高寒草原植物群落特征的影响

Effects of Different Enclosure Years on Community Characteristics of Alpine Steppe in Northern Xizang

围栏封育是最为常见的一种高寒草地生态近自然恢复的手段,本文以藏北地区班戈县11年长期围封、5年短期围封与正常放牧高寒草原类草地植物群落为研究对象,分析不同围封年限对高寒草原植物群落特征的影响,以期为后续生态恢复研究工作提供一个参考。研究发现:长期围封能显著提升群落平均高度(P <0.05),短期围封能显著提高群落地上生物量(P <0.05),随着围封年限增加,群落密度盖度也越来越高,但差异不显著(P> 0.05);长期围封能大幅降低草地退化指示种矮小火绒草(Heteropappus bowerii)在群落中的重要值,且能显著提高高寒草原优势种紫花针茅(Stipa purpurea)生物量(P <0.05);围封降低了群落Pielou物种均匀度指数,短期封育草地4个物种多样性指数均略高于长期围封草地(P> 0.05)。

Enclosure is one of the most common means of near-natural restoration of alpine grassland ecology.In this study,with 11 years of long-term enclosure,5 years of short-term enclosure and normal grazing of alpine grassland plant community as research objects,the effects of different enclosure years on the characteristics of alpine grassland plant community were analyzed in Bango County,Northern Xizang.The results showed that long-term enclosure significantly increased the average height of the plant community(P<0.05),short-term enclosure significantly increased the aboveground biomass of the plant community(P<0.05),and community density and cover increased with increasing years of enclosure(P>0.05).Long-term enclosure significantly reduced the importance of the grassland degradation indicator species(Heteropappus bowerii)in the community,and increased the biomass of the dominant species(Stipa purpurea)in alpine grassland(P<0.05).Enclosure reduced the Pielou species evenness index of plant community,and all four species diversity indices were higher in the short-term enclosed grassland than in the long-term enclosed grassland.