摘要
通过施肥形成的生产力由低到高的过程中,物种多样性往往降低。总体竞争假说认为对所有资源的竞争作用对多样性的影响随着生产力提高而加剧,导致物种多样性的下降;光竞争假说则认为随着生产力提高,种间竞争从低生产力时的地下竞争转向高生产力时的光竞争,是光竞争导致了物种多样性的下降。为了验证这两种假说,本文通过在甘南玛曲高寒草甸的均匀施肥实验,研究了光竞争对高寒草甸植物群落物种多样性和生产力关系的影响。结果表明:(1)随着施肥梯度的增加,大部分植物的生长速率加快,高度和叶面积增加;(2)随着施肥梯度的增加,植物群落地上总的生物量提高,叶面积指数增加,透光率降低,物种多样性减少;(3)个体大小不对称的光竞争导致了高寒草甸植物群落物种多样性随施肥梯度的增加而减少。
When productivity is manipulated experimentally via fertilization,species diversity almost always decreases.The total competition hypothesis proposes that competition for all resources has increasing effects on diversity as productivity increases.The light competition hypothesis,on the other hand,predicts a shift from competition for soil resources at low productivity to competition for light at high productivity.To test these hypotheses,we designed an equal-fertilizing experiment in Maqu,Gannan district,Gansu Province to study the effects of light competition on the relationship between productivity and species diversity.The results show that:(1) Growth rates,heights and leaf areas of many species increased significantly along the fertilizer gradient.(2) The above ground net primary productivity and LAI increased significantly along the fertilizer gradient,light transmittance and species richness decreased significantly along the fertilizer gradient.(3) Light competition may strongly impact plant community structure in productive communities where fertilizer never becomes limiting.Light competition can cause a decline in diversity with increased productivity in an alpine meadow.
出处
《西北植物学报》
CAS
CSCD
2004年第9期1646-1650,共5页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金重大项目(39893360-3)
甘肃省"九五"攻关重点项目(GK-971-2-35A)
关键词
光竞争
物种多样性
生产力
高寒草甸
light competition
species diversity
productivity
alpine meadow
