Lembrechts Jonas J, Pauchard Aníbal, Lenoir Jonathan, Nuñez Martín A, Geron Charly, Ven Arne, Bravo-Monasterio Pablo, Teneb Ernesto, Nijs Ivan, Milbau Ann
Centre of Excellence Plant and Vegetation Ecology, University of Antwerp, 2610 Wilrijk, Belgium;
Laboratorio de Invasiones Biológicas, Facultad de Ciencias Forestales, Universidad de Concepción, 4030000 Concepción, Chile.
Proc Natl Acad Sci U S A. 2016 Dec 6;113(49):14061-14066. doi: 10.1073/pnas.1608980113. Epub 2016 Nov 21.
Until now, nonnative plant species were rarely found at high elevations and latitudes. However, partly because of climate warming, biological invasions are now on the rise in these extremely cold environments. These plant invasions make it timely to undertake a thorough experimental assessment of what has previously been holding them back. This knowledge is key to developing efficient management of the increasing risks of cold-climate invasions. Here, we integrate human interventions (i.e., disturbance, nutrient addition, and propagule input) and climatic factors (i.e., temperature) into one seed-addition experiment across two continents: the subantarctic Andes and subarctic Scandinavian mountains (Scandes), to disentangle their roles in limiting or favoring plant invasions. Disturbance was found as the main determinant of plant invader success (i.e., establishment, growth, and flowering) along the entire cold-climate gradient, explaining 40-60% of the total variance in our models, with no indication of any facilitative effect from the native vegetation. Higher nutrient levels additionally stimulated biomass production and flowering. Establishment and flowering displayed a hump-shaped response with increasing elevation, suggesting that competition is the main limit on invader success at low elevations, as opposed to low-growing-season temperatures at high elevations. Our experiment showed, however, that nonnative plants can establish, grow, and flower well above their current elevational limits in high-latitude mountains. We thus argue that cold-climate ecosystems are likely to see rapid increases in plant invasions in the near future as a result of a synergistic interaction between increasing human-mediated disturbances and climate warming.
直到现在，非本地植物物种在高海拔和高纬度地区还很少见。然而，部分由于气候变暖，生物入侵如今在这些极端寒冷的环境中呈上升趋势。这些植物入侵使得对先前阻碍它们的因素进行全面的实验评估变得十分及时。这些知识对于有效管理日益增加的寒冷气候入侵风险至关重要。在此，我们将人为干预（即干扰、添加养分和引入繁殖体）和气候因素（即温度）整合到一个跨两大洲的种子添加实验中：亚南极安第斯山脉和亚北极斯堪的纳维亚山脉（斯堪的纳维亚山脉），以厘清它们在限制或促进植物入侵方面的作用。研究发现，干扰是沿整个寒冷气候梯度植物入侵者成功（即定居、生长和开花）的主要决定因素，在我们的模型中解释了总方差的40%-60%，且没有迹象表明本地植被有任何促进作用。更高的养分水平还额外刺激了生物量生产和开花。定居和开花随着海拔升高呈现出驼峰状反应，这表明竞争是低海拔地区入侵者成功的主要限制因素，而高海拔地区则是生长季温度较低。然而，我们的实验表明，非本地植物能够在高纬度山区远高于其当前海拔极限的地方定居、生长和开花。因此，我们认为，由于人类介导的干扰增加和气候变暖之间的协同相互作用，寒冷气候生态系统在不久的将来可能会出现植物入侵的快速增加。
