摘要
生物入侵已给人类社会带来了巨大的环境和经济损失,但关于植物入侵对生态系统的影响后果还知之甚少。土壤是生态系统的重要组成部分,植物入侵对土壤特性的影响已引起了生态学家的普遍关注。我们将原产北美的入侵杂草加拿大一枝黄花(Solidagocanadensis)和同属土著植物一枝黄花(S.decurrens)种植在具有相同利用历史的土壤中,通过检测生长后期不同植物下土壤特性的差异来研究加拿大一枝黄花的入侵后果。测定的土壤特性包括pH值、总碳、总氮、土壤有机质、硝态氮、铵态氮、净铵化速率、净硝化速率和净矿化速率等。野外选取了加拿大一枝黄花的典型入侵地上海江湾绿地进行土壤特性调查作为辅证。移栽实验和野外调查得到了基本一致的结果:加拿大一枝黄花调节了土壤pH值,增加了总碳、氮库和有机质库,降低了铵氮库和硝氮库。加拿大一枝黄花还促进了微生物的矿化速率和铵化速率,这表明该物种提高了土壤无机氮和铵氮的供给。控制无机氮浓度和无机氮形式的独立实验表明,高氮供给和富铵氮条件有利于加拿大一枝黄花的生长。本研究不仅为外来植物入侵后果的评估提供实验证据,而且为植物成功入侵的机制探索提供思路。
Invasive alien species （IAS） may threaten native biodiversity and cause considerable economic loss, so more and more attention has been directed towards the assessment of the impact of IAS on native ecosystems. Here, the effects of invasive Canadian goldenrod （Solidago canadensis） on soil properties were examined both in common gardens and under natural conditions. In the common garden experiment, S. canadensis and Chinese goldenrod （S. decurrens） were grown together. After a growing season, soil properties were measured, including pH, pools of soil nitrogen （N）, carbon （C）, organic matters （SOM） and extractable inorganic nitrogen （NH4-N and NO3-N）, and fluxes of net mineralization rate （MIN）, net ammonification rate （AMO） and net nitrification rate （NIT）. Similar variables representing soil properties were also measured in a field infested with S. canadensis. Our results show that the effects of S. canadensis invasions on soil properties observed in common gardens were similar to those under natural conditions. The invasion orS. canadensis increased the pools of N, C and SOM, but reduced the NH4-N and NO3-N; and S. canadensis also changed soil pH to ca. 8.2 in both garden and field experiments. However, the magnitude of change in several soil properties was larger in field experiments than in garden experiments, which might be the result of the difference in invasion time. C and N contents were only 10% higher in soil planted with S. canadensis than in the soil without S. canadensis in the garden experiments. In contrast, C and N contents were 100% higher in the soil colonized by S. canadensis than in the soil without S. canadensis in the field experiments. Similarly, SOM and NH4-N in the soil showed considerable difference between garden and field experiments. No significant difference in NO3-N was detected, either in garden or field experiments. Interms of fluxes, MIN increased by 3 times when the field was invaded by S. canadensis, indicating that S. canadensis invasions increased the inorganic nitrogen supply. Independent fertilization experiments controlling inorganic nitrogen form and total nitrogen concentration suggest that S. canadensis grew better at a higher ratio of NH4-N to NO3-N or at higher nitrogen levels. This study provided experimental data both for assessment of impacts of plant invaders on soil and for exploration of the mechanism of their successful invasions.
出处
《生物多样性》
CAS
CSCD
北大核心
2005年第4期347-356,共10页
Biodiversity Science
基金
国家自然科学基金(30170155)
作者简介
通讯作者Author for correspondence. E-mail： bool@fudan.edu.cn
