放牧格局和生境资源对矮嵩草(Kobresia humilis)分株生物量分配和补偿性生长的影响  

Effects of grazing disturbance pattern and nutrient availability on biomass allocation and compensatory growth in Kobresia humilis

作　　者：王文娟[1] 臧岳铭[1] 李英年[2] 席博[1] 郭华[1] 朱志红[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：《生态学报》2009年第5期2186-2194,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30671490)

摘　　要：为研究密集型克隆植物对放牧扰动和生境资源变化的生物量分配和补偿生长响应特性,验证克隆植物的觅食模型和3个有关植物个体补偿反应的假说(①放牧优化假说,grazing optimization hypothesis,GOH;②反应连续谱假说,continuum of responseshypothesis,CRH;③增长率模型,growth rate model,GRM),在具有不同放牧利用格局和土壤养分水平的高寒矮嵩草草甸(Ⅰ.畜圈草地:重度放牧、资源丰富;Ⅱ.牧道草地:中度放牧、资源贫乏;Ⅲ.封育草地:不放牧、资源贫乏)中通过设置扣笼/无扣笼样方对其建群种矮嵩草(Kobresia humilis)进行了研究。结果表明不论当年解除家畜放牧与否,春季采摘率越高(畜圈草地),分株生物量向生长的投入越少,向贮藏器官的投入越多。繁殖分配在中度采摘下最高(牧道草地),扣笼内外分株各部分的生物量分配无差异。矮嵩草分株在中度采摘×资源贫乏条件下产生了超补偿响应,在重度采摘×资源丰富条件下为等量补偿,重度采摘导致分株密度显著减少。生物量分配格局与觅食模型的预测不符。补偿生长响应特性证实了GOH和GRM的预测,但与CRH的预测不符。这说明在研究地区放牧扰动格局对克隆植物矮嵩草分株的生物量分配和补偿生长具有重要影响,适度放牧利用更利于引起超补偿,而重度利用可能会对该种群的长期保持产生不利影响。A field experiment was conducted to study biomass allocation and compensatory growth of phalanx clonal plants under different grazing disturbance pattern and nutrient availability. We also tested foraging models for clonal plants and some hypotheses related to compensatory growth patterns, such as the grazing optimization hypothesis （GOH）, the continuum of responses hypothesis （CRH）, and the growth rate model（GRM）. We examined an alpine meadow elonal plant Kobresia humilis in a field grazing defoliation experiment by domestic animals through setting grazed/ungrazed pots. There were 3 habitats, （ Ⅰ ） pen pasture, with heavy defoliation ratio ×high nutrient availability. （ Ⅱ ） pass pasture, with moderate defoliation ratio ×low nutrient availability. （ Ⅲ ） ungrazed availability. Our results showed that regardless of release from grazing pasture, with null defoliation ratio × low nutrient defoliation in the current year, the more the risk of defoliation encountered by plants in spring, the lower the biomass allocation to growth organ （leaves）, and the greater the biomass allocation to storage organ （rhizomes）. The reproductive allocation was highest in the conditions of moderate defoliation ratio and low nutrient availability. However, biomass allocation to different parts of the ramet did not differ between grazed and ungrazed treatments. Overcompensation was found in habitat 2, whereas fullcompensation occurred in habitat 1. Moreover, in habitat 1 ramet density significantly decreased. The pattern of biomass allocation in the species was not consistent with the foraging model prediction. The pattern of compensatory growth supported the prediction of GOH and GRM, however, it did not agree with CRH. These results suggested grazing defoliation significantly affect the patterns of biomass allocation and compensatory growth of K. humilis ramet. Moderate defoliation causes the overcompensation. But heavy defoliation will have a negative effect on long-term persistence of the popul

关 键 词：克隆植物 生物量分配 补偿性生长 放牧 高寒草甸 

分 类 号：S812[农业科学—草业科学]