放牧强度和生境资源对高寒草甸群落补偿能力的影响  

Effect of grazing disturbance and nutrient availability on the compensatory responses of community in alpine meadows

作　　者：席博[1] 朱志红[1] 李英年[2] 王文娟[1] 臧岳铭[1] 

机构地区：[1]陕西师范大学生命科学学院,西安710062 [2]中国科学院西北高原生物研究所,西宁810008

出　　处：《兰州大学学报（自然科学版）》2010年第1期77-84,共8页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金项目(30671490)

摘　　要：研究了不同放牧强度、土壤养分和水分条件对高寒矮嵩草草甸三种生境的群落物种多样性及补偿能力的影响。结果表明:物种丰富度指数R和Shannon-Weiner多样性指数H′在牧道和封育草地显著高于畜圈生境,牧道生境的物种数最高,而畜圈物种数最少,仅为牧道的54%。地上生物量在牧道和畜圈生境均发生超补偿反应,地下生物量在畜圈为等量补偿,而在牧道发生超补偿反应。对畜圈生境群落地上生物量超补偿反应贡献最大的是垂穗披碱草,而对地下生物量等补偿反应贡献最大的是矮嵩草。在牧道生境中,对地上、地下生物量超补偿反应贡献最大的均为矮嵩草。群落地上、地下生物量的相对增长率在生境间无显著差异。土壤含水量与补偿生长无相关关系,地上生物量的补偿性生长与采摘率和土壤全氮质量分数正相关。这些结果支持中度干扰假说,同时说明高寒草甸群落的补偿响应模式与群落物种在生境间补偿量的消长变化有直接关系,补偿能力同时受放牧强度和土壤营养资源,特别是氮素营养的共同影响,而土壤水分的影响相对较小。A field experiment was conducted to study the compensatory growth and species diversity of community under different grazing intensities, nutrient availabilities and water contents of the soil. The results showed that the species richness index R and the species diversity index H＇ in pass habitat and ungrazed habitat was higher than that in pen habitat. The number of species was the lowest in pen habitat, which was only 54% of that in pass. The aboveground biomass showed overcompensation at the both pass and pen habitats, the belowground biomass showed exact compensation at the pen habitat and overcompensation at the pass habitat. In the pen habitat, the Elymus nutans and Kobresia humilis made a most important contribution to the aboveground overcompensation and the belowground fullcompensation, respectively. In pass pasture, Kobresia humilis made a most important contribution to the above and belowground overcom- pensation. The relative growth rate of the above and the belowground biomass did not differ among habitats,the water contents of the soil was not correlated with the above and belowground compensation, only the aboveground compensation was positively related to the defoliation rate and the total nitrogen content of the soil. These results supported the intermediate disturbance hypothesis and suggesteded that the compensatory pattern in community level was directly correlated with the compensatory varieties in species level; the compensatory growth of alpine meadows was mainly affected by the grazing intensity and the resource availability, especially the nitrogen nutrition and the impact of soil moisture was relatively small.

关 键 词：植物群落 补偿生长 生物量 放牧 

分 类 号：Q948[生物学—植物学]