围栏封育对温性草甸草原植物群落构成及生态位特征的影响

为明确温性草甸草原群落构成和生态位对围栏封育的响应,运用了Levins生态位指数和Pianka生态位重叠指数以及物种多样性指数分析围栏内外植物种对资源的利用情况和种间竞争情况。结果表明:围栏封育显著促进退化草地植被恢复,植被地上生物量和地下生物量分别较对照提高255.06%,51.06%;物种多样性与丰富度分别增加了10.36%,10.34%。围封样地内生态位宽度排名前2位的植物为囊花鸢尾和羊草,生态位宽度值分别为0.921和0.873;自由放牧样地生态位宽度排在前2的植物为蒲公英和寸草苔,生态位宽度值依次为0.912和0.791。围栏封育可以显著提高草地生产力,并且对物种多样性也有一定的促进作用,是应对退化温性草甸草原恢复的有效措施;与自由放牧相比,围栏封育增加了群落植物种整体生态位重叠值和种间竞争。

Effects of fence enclosure on the plant community composition and niche characteristics in a temperate meadow steppe

This study explored the effects of fence enclosure on community composition and niche characteristics in temperate meadow steppe. The indexes Levins niche breadth, Pianka niche overlap and species diversity were used to evaluate the degree of resource utilization by species and the intensity of interspecific competition inside and outside the enclosure. It was found that: the fencing enclosure significantly promoted vegetation restoration of degraded grassland. The aboveground biomass and belowground biomass in the enclosure treatments were enhanced by 255.06% and 51.06%, respectively. The species diversity and richness were enhanced in fenced enclosures by 10.36% and 10.34%, respectively. The two species with the highest niche breadth in enclosures were Iris ventricosa and Leymus chinensis, with values of 0.921 and 0.873, respectively. In comparison, the two species with the highest niche breadth in the freely grazed grassland were Taraxacum mongolicum and Carex duriuscula, with values of 0.912 and 0.791, respectively. Our results clearly show that enclosure by fencing is an efficient restoration measure that not only promotes species diversity but also improves grassland productivity. Compared with free grazing, fencing enclosure increases the overall niche overlap value and inter-species competition of plant communities and their component plant populations.