Functional trait differences and trait plasticity mediate biotic resistance to potential plant invaders
Functional trait differences and trait plasticity mediate biotic resistance to potential plant invaders
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DOI：
10.1111/1365-2745.12928
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发表时间：
2018-07-01
影响因子：
5.5
通讯作者：
Carboni, Marta
中科院分区：
文献类型：
--
作者：
Conti, Luisa;Block, Svenja;Carboni, Marta
1. 生物抗性是全世界潜在入侵者的重要天然屏障，但驱动这种抗性的根本机制仍然存在争议。从理论上讲，本土社区应该击退功能相似且竞争相同资源的入侵者，以及具有较弱竞争特征的入侵者。然而，环境压力、生命率之间的权衡和竞争引起的可塑性状变化可能会改变预期的竞争结果，从而影响入侵动态。2．为了测试性状分布和生物抗性之间的理论联系，我们对入侵本地植物群落的 25 种非本地观赏物种进行了中生态实验。每个非本地物种都在有和没有本地群落的情况下在两种浇水处理（常规和减少）下生长。我们测量了生物抗性，即在有或没有社区的情况下生长的非本地个体在生存、生长和繁殖方面的表现差异。我们根据植物高度、特定叶面积和种子质量的组合，量化了非本地观赏个体和本地群落之间的整体功能差异。然后，假设这些特征中的每一个也可能与竞争能力相关，我们测量了非本地人在特征层次上的位置。虽然高度与光拦截的竞争能力呈正相关，但保守的叶子和种子特征为其他资源的竞争提供了更大的容忍度。最后，我们量化了竞争引起的非本地个体的可塑性状转变。3．事实上，本土群落通过降低入侵者的生存率来排斥功能相似的个体。同时，具有较大特定叶面积的较短观赏个体在生命率方面对群落生物抗性的耐受性较差，尽管性状层次的影响通常取决于浇水条件。最后，非本地人通过改变自己的特征来应对竞争。最重要的是，具有更多竞争性状的个体也能够通过竞争引起的可塑性状转变来克服生物抗性。4。合成。我们的结果强调，功能差异和性状层次都介导了对观赏植物入侵者的生物抗性。然而，环境压力以及生命率的相反趋势也有影响。此外，可塑性状的转变可以增强潜在入侵者的竞争优势，从而产生积极的反馈。
1. Biotic resistance represents an important natural barrier to potential invaders throughout the world, yet the underlying mechanisms that drive such resistance are still debated. In theory, native communities should repel both functionally similar invaders which compete for the same resources, and invaders which possess less competitive traits. However, environmental stress, trade-offs across vital rates and competition-induced plastic trait shifts may modify expected competitive outcomes, thereby influencing invasion dynamics.2. In order to test these theoretical links between trait distributions and biotic resistance, we performed a mesocosm experiment with 25 non-native ornamental species invading native plant communities. Each non-native species was grown with and without the native community under two watering treatments (regular and reduced). We measured biotic resistance as the difference in performance of non-native individuals grown with and without the community in terms of their survival, growth and reproduction. We quantified overall functional dissimilarity between non-native ornamental individuals and native communities based on the combination of plant height, specific leaf area and seed mass. Then, assuming each of these traits is also potentially linked to competitive ability, we measured the position of non-natives on trait hierarchies. While height is positively correlated with competitive ability for light interception, conservative leaf and seed characteristics provide greater tolerance to competition for other resources. Finally, we quantified plastic trait shifts of non-native individuals induced by competition.3. Indeed, the native community repelled functionally similar individuals by lowering the invader's survival rate. Simultaneously, shorter ornamental individuals with larger specific leaf areas were less tolerant to biotic resistance from the community across vital rates, although the effect of trait hierarchies often depended on watering conditions. Finally, non-natives responded to competition by shifting their traits. Most importantly, individuals with more competitive traits were able to overcome biotic resistance also through competition-induced plastic trait shifts.4. Synthesis. Our results highlight that both functional dissimilarity and trait hierarchies mediate biotic resistance to ornamental plant invaders. Nevertheless, environmental stress as well as opposing trends across vital rates are also influential. Furthermore, plastic trait shifts can reinforce potential invaders' competitive superiority, determining a positive feedback.