Data from: The effects of climate warming and disturbance on the colonization potential of ornamental alien plant species

1. A large number of alien plant species have been introduced as ornamental garden plants to Europe, but relatively few have become invasive. Low climatic suitability may be limiting the current invasion potential of many alien ornamental species. However, with ongoing disturbance and climate change, this barrier may be reduced for some species.
2. Here we tested how colonization ability (a prerequisite for invasion) of frequently planted alien ornamentals depends on disturbance and heating, and on their species characteristics. We sowed seeds of 37 non-naturalized alien herbaceous garden-plant species into native grassland plots with and without disturbance, and with and without infrared heating lamps. To assess whether their responses differ from those within the regional wild flora, we also sowed 14 native species and 12 naturalized alien species. During two years, we assessed the likelihoods of germination, first-year survival, second-year survival and flowering of these 63 study species.
3. The heating treatment, which also reduced soil moisture, decreased all measures of colonization success, but more so for sown native species than for the non-naturalized and naturalized alien ones. The disturbance treatment increased colonization success, and because heating decreased productivity of the undisturbed grassland plots, it also increased invasibility of these plots. Average colonization success of non-naturalized aliens was reduced by heating, but some species were not affected or performed even better with heating, particularly those with an annual life span and a high seed mass. Winter hardiness improved colonization ability of non-naturalized aliens, but this advantage was reduced in the heated plots.
4. Synthesis. Disturbance increased and heating decreased the absolute colonization success of most of the 63 species sown. However, heating had stronger adverse effects on the resident grassland and sown native species than either type of sown alien species. Together, these results suggest that some alien plants may have greater colonization success relative to native plants under a warmer climate.

1. 已有大量外来植物物种 (alien plant species) 作为观赏园艺植物 (ornamental garden plants) 被引入欧洲，但其中真正成为入侵物种的相对较少。较低的气候适宜性 (climatic suitability) 可能限制了多数外来观赏植物当前的入侵潜力 (invasion potential)。不过，随着持续存在的生态干扰与气候变化 (climate change)，这一限制屏障或会对部分物种有所缓解。
2. 本研究探究了频繁栽培的外来观赏植物的定殖能力 (colonization ability，入侵的先决条件) 如何受生态干扰、增温处理及其物种特性的影响。我们将37种非归化外来草本园艺植物 (non-naturalized alien herbaceous garden-plant species) 的种子播种于设置了干扰/无干扰、红外加热灯 (infrared heating lamps)/无红外加热灯的本地草原样地中。为评估其响应与区域野生植物区系 (regional wild flora) 内物种的响应差异，我们同时播种了14种本地植物与12种归化外来植物 (naturalized alien species)。在为期两年的监测中，我们评估了这63种研究物种的种子萌发概率、一年生幼苗存活率、二年生植株存活率以及开花概率。
3. 增温处理同时降低了土壤湿度 (soil moisture)，其降低了所有定殖成功率的评估指标，且对播种的本地物种的抑制作用强于非归化外来与归化外来物种。干扰处理则提升了定殖成功率；由于增温处理降低了未干扰草原样地的群落生产力，其同时提升了这些样地的可入侵性 (invasibility)。非归化外来物种的平均定殖成功率因增温处理而下降，但部分物种未受影响，甚至在增温条件下表现更优，这类物种多具有一年生生活型与较高的种子质量 (seed mass)。越冬抗寒性 (winter hardiness) 提升了非归化外来物种的定殖能力，但该优势在增温样地中有所减弱。
4. 综合分析：对于本次播种的63种植物中的绝大多数而言，干扰处理提升了其绝对定殖成功率，而增温处理则降低了该指标。相较于两类播种的外来物种，增温处理对本地原生草原群落与播种的本地物种产生了更强的负面影响。综合来看，上述结果表明，在气候变暖的场景下，部分外来植物的定殖成功率或将高于本地植物。