Invasion success of exotic in natural ecosystems: the role of disturbance, plant attributes and freedom from herbivores
Invasion success of exotic in natural ecosystems: the role of disturbance, plant attributes and freedom from herbivores
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DOI：
10.1016/s0006-3207(03)00294-5
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发表时间：
2004-05-01
影响因子：
5.9
通讯作者：
Leishman, MR
中科院分区：
文献类型：
--
作者：
Lake, JC;Leishman, MR
外来物种对自然生态系统的入侵是全球生物多样性的主要威胁。我们评估了两种替代（但不是唯一的）假设，以解释外来物种在城市荒地低肥力砂岩衍生土壤在澳大利亚悉尼的成功。这些是外来物种的成功促进：（1）在特定的干扰类型的植物属性;（2）从食草动物的自由。我们测试了这些在网站受到不同类型的干扰：营养和水富集（以下雨水出口），营养富集（河岸带的小溪与城市集水区）和物理干扰（轨道），和控制网站。在每个站点，我们估计所有物种的覆盖率，并调查了食草动物造成的损害。物种被分为本地，非入侵外来或入侵外来。我们发现，网站没有任何干扰不支持外来植物。物理干扰低肥力土壤上的网站只支持一个外来物种，这表明营养富集是外来物种入侵低肥力土壤的一个重要先决条件。外来物种覆盖率最高，本地物种丰富度最减少的地区最高的养分富集。外来入侵物种和非外来入侵物种的叶草食动物的水平显着低于本地物种，这意味着释放害虫本身不能占入侵物种的成功。无论干扰类型如何，外来入侵物种的比叶面积始终高于非外来入侵物种和本地物种的比叶面积。在土壤肥力较高的物理干扰地点，外来物种是开花时间长的小型草本植物和草，种子小，无人协助或风传播。在营养丰富的地点，外来物种更有可能是攀缘植物，能够繁殖植物，并通过脊椎动物传播种子。因此，不同的植物属性有助于外来物种的成功在不同的干扰类型。我们发现入侵性外来种和非入侵性外来种之间最明显的一致差异是比叶面积，这表明大的比叶面积有利于入侵。(C)2003 Elsevier Ltd.保留所有权利。
Invasion of natural ecosystems by exotic species is a major threat to biodiversity globally. We assessed two alternative (but not exclusive) hypotheses to explain the success of exotic species in urban bushland on low fertility sandstone-derived soils in Sydney, Australia. These were that success of exotic species is promoted by: (1) plant attributes in particular disturbance types; and (2) freedom from herbivores. We tested these at sites subject to different types of disturbance: nutrient and water enrichment (below stormwater outlets), nutrient enrichment (riparian zones of creeks with an urban catchment) and physical disturbance (tracks), and control sites. At each site we estimated percentage cover of all species and surveyed leaves for damage by herbivores. Species were classified as native, non-invasive exotic or invasive exotic. We found that sites without any disturbance did not support exotic plants. Physically disturbed sites on low fertility soils supported only one exotic species, suggesting that nutrient enrichment is a critical prerequisite for exotic species invasion on low fertility soils. Exotic species cover was highest and native species richness most reduced in areas of highest nutrient enrichment. Both invasive exotic and non-invasive exotic species had significantly lower levels of leaf herbivory than native species, implying that release from pests alone cannot account for the success of invasive species. Specific leaf area of invasive exotic species was consistently higher than specific leaf area of non-invasive exotic and native species, regardless of disturbance type. In physically disturbed sites of higher soil fertility, exotic species were small herbs and grasses of long flowering duration and with small unassisted or wind-dispersed seeds. In sites subject to nutrient-enrichment, exotic species were more likely to be climbers, able to propagate vegetatively, and with seeds dispersed by vertebrates. Thus different plant attributes contribute to exotic species success under different disturbance types. The clearest consistent difference we found between invasive exotic and non-invasive exotic species was in specific leaf area, suggesting that large specific leaf area facilitates invasiveness. (C) 2003 Elsevier Ltd. All rights reserved.