Brendel Marco R, Schurr Frank M, Sheppard Christine S
Institute of Landscape and Plant Ecology University of Hohenheim Stuttgart Germany.
Division of Conservation in Agriculture German Federal Agency for Nature Conservation Bonn Germany.
Ecol Evol. 2023 Sep 1;13(9):e10468. doi: 10.1002/ece3.10468. eCollection 2023 Sep.
Alien plants experience novel abiotic conditions and interactions with native communities in the introduced area. Intra- and interspecific selection on functional traits in the new environment may lead to increased population growth with time since introduction (residence time). However, selection regimes might differ depending on the invaded habitat. Additionally, in high-competition habitats, a build-up of biotic resistance of native species due to accumulation of eco-evolutionary experience to aliens over time may limit invasion success. We tested if the effect of functional traits and the population dynamics of aliens depends on interspecific competition with native plant communities. We conducted a multi-species experiment with 40 annual Asteraceae that differ in residence time in Germany. We followed their population growth in monocultures and in interspecific competition with an experienced native community (varying co-existence times between focals and community). To more robustly test our findings, we used a naïve community that never co-existed with the focals. We found that high seed mass decreased population growth in monocultures but tended to increase population growth under high interspecific competition. We found no evidence for a build-up of competition-mediated biotic resistance by the experienced community over time. Instead, population growth of the focal species was similarly inhibited by the experienced and naïve community. By comparing the effect of experienced and naïve communities on population dynamics over 2 years across a large set of species with a high variation in functional traits and residence time, this study advances the understanding of the long-term dynamics of plant invasions. In our study system, population growth of alien species was not limited by an increase of competitive effects by native communities (one aspect of biotic resistance) over time. Instead, invasion success of alien plants may be limited because initial spread in low-competition habitats requires different traits than establishment in high-competition habitats.
外来植物在引入地区会经历新的非生物条件，并与当地群落发生相互作用。自引入（居留时间）以来，新环境中对功能性状的种内和种间选择可能会导致种群增长随时间增加。然而，选择机制可能因入侵栖息地的不同而有所差异。此外，在高竞争栖息地中，由于本地物种随着时间的推移对外来物种积累了生态进化经验，其生物抗性的增强可能会限制入侵的成功。我们测试了功能性状的影响以及外来物种的种群动态是否取决于与本地植物群落的种间竞争。我们对40种在德国居留时间不同的一年生菊科植物进行了多物种实验。我们跟踪了它们在单一栽培以及与经验丰富的本地群落进行种间竞争（焦点物种与群落之间的共存时间不同）时的种群增长情况。为了更有力地检验我们的发现，我们使用了一个从未与焦点物种共存过的单纯群落。我们发现，高种子质量在单一栽培中会降低种群增长，但在高强度种间竞争下往往会增加种群增长。我们没有发现有证据表明经验丰富的群落会随着时间的推移积累竞争介导的生物抗性。相反，焦点物种的种群增长受到经验丰富的群落和单纯群落的抑制程度相似。通过比较经验丰富的群落和单纯群落在两年时间里对一大组功能性状和居留时间差异很大的物种的种群动态的影响，本研究增进了对植物入侵长期动态的理解。在我们的研究系统中，外来物种的种群增长并没有受到本地群落竞争效应增加（生物抗性的一个方面）的限制。相反，外来植物的入侵成功可能受到限制，因为在低竞争栖息地的初始扩散需要的性状与在高竞争栖息地定殖所需的性状不同。
