酸雨对外来植物入侵的影响

Effects of acid rain on the invasion of non-native plants

酸雨和外来种入侵都是全球关注的问题。结合外来入侵植物的生态适应特性以及酸雨的危害特征,系统分析了酸雨对外来植物入侵产生的影响。酸雨对外来植物入侵的影响是复杂多样的。酸雨导致群落冠层稀疏,群落透光率增加,加之氮沉降后土壤、水体氮素的增加,有利于生长力强的外来喜阳植物入侵;酸雨加速土壤酸化,促使基本离子淋失以及A1毒等危害植物的生长发育,植物的内源激素以及化感作用发生改变,适应力和耐受力强的外来植物在与本地植物竞争中处于相对优势而成为入侵种;酸雨以及外来植物入侵改变了土壤微生物群落结构,影响本地植物的生长而促使外来植物的入侵。

Acid rain as products of anthropogenic pollution consist a major environmental problem for the world. The effects of acid rain on the invasion of non-native plants are analyzed in this paper. The non-native plant can invade into the community because of the differences between invasive and native plants in a variety of physiological and ecological traits, such as growth ability, adaptability and resistance, et al. Acid rain results in the deposition of strong acids followed by a decrease in soil or water pH, leaching of basic cations and following aluminium toxicity in soils. These processes cause adverse responses of tree in growth and physiology, and result in canopy plants die-back and canopy defoliation （crown-thinning） and, consequently, influence the population dynamics of plants in the community understory, non-native sun grass with higher growth abilities may become an invasive species for the enhanced light penetration through damaged community canopy, and the increase of nitrogen content in soil or water by nitrogen deposition. The endogenous hormone content and allelochemicals in plant may also be changed under the stress of acid rain, some non-native plants may be dominant within the plant community for their higher resistance and adaptability to the stress. The acidification intensified by acid rain and the invasion of non-native plant may change soil microbes, and this change may be of advantage to the non-native plant invasion. Future studies are recommended to （a） effects of acid deposition on the allelopathy of non-native plants; （b） effects of acid deposition on the endogenous hormone content of non-native plants; and （c） dynamics of soil microbes induced by acid rain or invasive plants, and the role of the soil microbes play in the invasive processes of non-native plants.