Rapid nutrient cycling in leaf litter from invasive plants in Hawai'i
Rapid nutrient cycling in leaf litter from invasive plants in Hawai'i
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DOI：
10.1007/s00442-004-1679-z
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发表时间：
2004-12-01
期刊：
影响因子：
2.7
通讯作者：
Vitousek, PM
中科院分区：
文献类型：
--
作者：
Allison, SD;Vitousek, PM
有助于入侵植物物种的建立和传播的生理特征也可能对生态系统过程产生影响。许多入侵植物普遍存在的特征，例如比叶面积大、生长速度快和叶子养分浓度升高，可以改善凋落物质量，并提高分解速度和养分循环。为了测试这些生态系统影响，我们测量了夏威夷群岛对照地块和施氮+磷肥地块中 11 种林下植物的初始落叶特性、分解率和养分动态。其中包括五种常见的本地物种，其中四种是蕨类植物，以及六种侵略性入侵物种，包括五种被子植物和一种蕨类植物。我们发现落叶腐烂率存在 50 倍的差异，本地植物的腐烂速度为 0.2 - 2.3 年 (-1)，入侵者的腐烂速度为 1.4 - 9.3 年 (-1)。这种差异是由于原生蕨类植物凋落物的分解率非常低造成的。施肥显着增加了两种本地物种和两种入侵物种的落叶腐烂率。大多数入侵垃圾类型比本地垃圾类型损失氮和磷的速度更快、数量更多。除三种本土蕨类植物外，所有凋落物类型在 100 天分解后都会损失氮，并且在实验结束时（204-735 天），除最顽固的本土蕨类植物外，所有凋落物类型都损失了超过 50% 的初始磷。如果入侵性林下植物取代了本地物种，由于入侵性凋落物的快速分解和养分释放，养分循环率可能会急剧增加。这些变化可能会对夏威夷的入侵产生积极的反馈，因为许多入侵植物在营养丰富的土壤上茁壮成长。
Physiological traits that contribute to the establishment and spread of invasive plant species could also have impacts on ecosystem processes. The traits prevalent in many invasive plants, such as high specific leaf areas, rapid growth rates, and elevated leaf nutrient concentrations, improve litter quality and should increase rates of decomposition and nutrient cycling. To test for these ecosystem impacts, we measured initial leaf litter properties, decomposition rates, and nutrient dynamics in 11 understory plants from the Hawaiian islands in control and nitrogen + phosphorus fertilized plots. These included five common native species, four of which were ferns, and six aggressive invasive species, including five angiosperms and one fern. We found a 50-fold variation in leaf litter decay rates, with natives decaying at rates of 0.2 - 2.3 year(-1) and invaders at 1.4 - 9.3 year(-1). This difference was driven by very low decomposition rates in native fern litter. Fertilization significantly increased the decay rates of leaf litter from two native and two invasive species. Most invasive litter types lost nitrogen and phosphorus more rapidly and in larger quantities than comparable native litter types. All litter types except three native ferns lost nitrogen after 100 days of decomposition, and all litter types except the most recalcitrant native ferns lost > 50% of initial phosphorus by the end of the experiment (204-735 days). If invasive understory plants displace native species, nutrient cycling rates could increase dramatically due to rapid decomposition and nutrient release from invasive litter. Such changes are likely to cause a positive feedback to invasion in Hawai'i because many invasive plants thrive on nutrient-rich soils.