高原鼠兔干扰对青海湖流域高山嵩草草甸植物多样性及地上生物量的影响

采用堵洞法设置高原鼠兔干扰区和非干扰区,然后在干扰区和非干扰区内利用样方法研究了高原鼠兔干扰对青海湖流域高山嵩草草甸植物多样性和地上生物量的影响。结果表明,植物物种多样性和不同植物功能群多样性对高原鼠兔干扰的响应并不一致,其中干扰增加了杂类草功能群丰富度指数与物种丰富度指数,降低了物种均匀度指数、莎草科功能群丰富度指数和禾草科功能群均匀度指数(P0.05)。干扰区内物种均匀度指数、物种丰富度指数和杂类草功能群丰富度指数随干扰强度增加而呈增加趋势,但禾草科功能群均匀度指数却呈显著降低趋势。虽然高原鼠兔干扰显著降低了植物群落总生物量,莎草科、禾草科和豆科功能群生物量(P0.05),但显著增加了杂类草功能群生物量(P0.05)。干扰区随干扰程度增加,莎草科功能群和豆科功能群生物量逐渐降低,杂类草功能群生物量逐渐增加,而禾草科功能群生物量则先增加后降低。鉴于高山嵩草草甸植物群落物种多样性和功能多样性对高原鼠兔干扰的响应不一致,植物物种多样性和功能群多样性之间不能互相替代。

Effects of plateau pika(Ochotona crzoniae)disturbances on plant species diversity and aboveground plant biomassin a Kobresia pygmaea meadow in the Qinghai Lake Region

A field survey was carried out to determine the effects of plateau pika disturbances on plant species diversity and productivity in a Kobresiapygmaea meadow in the Qinghai Lake Region.A random stratified paired sampling design was used to select a disturbed area containing burrow entrances and plateau pika simul-taneously,and an undisturbed area without burrow entrances or plateau pika.The field experiment was con-ducted in early May,2015.The dominant plant was the same in the disturbed and undisturbed areas,but its degree of dominance was lower in the disturbed area than in the undisturbed area.Ten plots (25 m×25 m) were randomly placed with at least 25 m distance between plots.Each plot was fenced to exclude other wild herbivores.In each plot,vegetation was sampled in three subplots on the diagonal (each 1 m×1 m,with at least 10 m distance between subplots).The results showed that plateau pika disturbances had different effects on species diversity and plant functional groups.Plateau pika disturbances increased the richness index of weeds and plant species richness,and decreased the plant evenness index,the richness index of Cyperaceae,and the evenness index of Gramineae (P<0.05).In disturbed areas,plant species richness and evenness and the rich-ness index of weeds gradually increased with increasing plateau pika disturbance levels,while the evenness in-dex of Gramineae decreased.Plateau pika disturbances significantly reduced the total community biomass (P<0.05),but the trends in the changes of biomass differed among functional groups.Plateau pika disturbances significantly decreased the biomass of Cyperaceae,Gramineae,and Leguminosae,but increased the biomass of weeds (P<0.05).With increasing plateau pika disturbance levels,the biomass of Cyperaceae and Legumino-sae decreased,the biomass of weeds increased,and the biomass of Gramineae first increased and then de-creased.These results suggested that analyses of plant diversity cannot replace analyses of plant functional di-versity when trying to understand the responses of alpine meadows to plateau pika disturbances.