爆发型种群铜锤草增长的密度调节

Density regulation of explosive population growth in Oxalis corymbosa

“生态入侵”已成为国际上生态学领域关心的热点问题之一 ,尤其对引种引起的生态灾难已越来越受到人们的广泛关注。以引进种铜锤草为研究对象 ,通过实验从形态及数量动态、产量等方面考察铜锤草种群调控特点。研究表明 ,铜锤草种群的密度制约主要有以下特点 :①铜锤草单株构件具有随种群密度的增加调节自身数量和生物量的能力 ,以叶构件的数量和生物量对密度的反应最灵敏。②密度对种群数量动态的调节表现在个体和构件两个水平。铜锤草种群叶构件调节表现出各密度种群单株叶密度有如下趋势 :低密度种群 >中等密度种群 >高密度种群 ,而个体数量调节仅出现在高密种群。③密度对单株生物量和小鳞茎产量影响极显著 ;单株生物量与种群密度的关系基本符合 - 3/2幂定律 ,小鳞茎产量与种群密度也表现出近似的幂函数关系。

Ecological invasion is one of the most popular ecological focuses around the world.Ecological calamities caused by introducing exotic species were concerned recently.The mechanism of population regulation of Oxalis corymbosa,a non-indigenous species,was studied in 1999.Density regulation was determined by characteristics of morphology,dynamics and production.Modular populations could regulate their quantities and biomass.Although varied in module,leaves number and biomass were the most flexible and sensitive.Density regulation displayed on the levels of individual and module.Regulation on the level of leaf population caused that peak number of leaves per individual was different among populations.Regulation and self-thinning on the level of individual only happened in high-density population.Biomass and bulb production were influenced significantly by density.The relationship between biomass per ramet and population density conforms to -3/2-power law.Similar relationship happened between bulbs production and population density.