Ecological communities are dynamic entities subjected to extinction/colonization events. Because species are connected through complex interaction networks, the arrival of a new species is likely to affect various species across the community, as observed in plant biological invasions. However, plant invasions usually represent extreme scenarios in which the community is strongly dominated by the alien species, confounding the effects of a change in species composition with a massive increase in floral resource availability. Our study addresses changes in plant community composition involving native species, a common phenomenon under the current climate change scenario in which plants are modifying their distribution ranges. We experimentally manipulated patches of a natural scrubland community by introducing a native plant (henceforth colonizing plant). To avoid introducing a disproportionate amount of floral resources we adjusted the number of flowers of the colonizing plant to the amount of floral resources locally available in each patch. We had two objectives: 1) to analyse the effects of the arrival of a new plant on the pollinator community, the rearrangement of plant-pollinator interactions and the structure of the plant-pollinator network; 2) to evaluate potential consequences for pollination and the reproductive success of resident plant species. The colonizing plant acted as a magnet species, attracting bumble bees and facilitating interactions to other plants through spill-over. The introduction of the colonizing plant also affected the structure of plant-pollinator networks (colonized networks were more generalized and more nested than control networks) and modified the arrangement of plant and pollinator species into modules. Ultimately, these changes resulted in higher heterospecific (but not conspecific) pollen deposition and had contrasting effects on the reproductive success of two resident plant species (higher fruit set and lower seed set, respectively). Our study shows that relationships between plants and pollinators are rapidly rearranged in response to novel situations (even when the new plant is not overly dominant), with important functional consequences on pollination and plant reproductive success. Our study establishes a link between network structure and pollination and plant reproductive success, which may be mediated by differences among pollinator species in foraging behavior.

中文翻译：

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附近的一种新本地植物：对植物传粉网络、授粉和植物繁殖成功的影响

生态群落是受灭绝/殖民化事件影响的动态实体。由于物种通过复杂的相互作用网络相互联系，正如在植物生物入侵中所观察到的那样，新物种的到来可能会影响整个社区的各种物种。然而，植物入侵通常代表极端情况，在这种情况下，外来物种强烈控制群落，将物种组成变化的影响与花卉资源可用性的大量增加混为一谈。我们的研究解决了涉及本地物种的植物群落组成的变化，这是当前气候变化情景下植物正在改变其分布范围的常见现象。我们通过引入本地植物（此后称为殖民植物）来实验性地操纵天然灌木丛群落的斑块。为了避免引入不成比例的花卉资源，我们将定植植物的花卉数量调整为每个斑块中当地可用的花卉资源数量。我们有两个目标：1）分析新植物的到来对传粉媒介群落、植物-传粉媒介相互作用的重新排列以及植物-传粉媒介网络结构的影响；2) 评估传粉和驻地植物物种繁殖成功的潜在后果。殖民植物充当磁铁物种，吸引大黄蜂并通过溢出促进与其他植物的相互作用。定植植物的引入也影响了植物-传粉媒介网络的结构（定植网络比控制网络更广泛和嵌套更多），并将植物和传粉媒介物种的排列修改为模块。最终，这些变化导致更高的异种（但不是同种）花粉沉积，并对两种常驻植物物种（分别为较高坐果和较低结实率）的繁殖成功产生对比影响。我们的研究表明，植物和传粉者之间的关系会根据新情况迅速重新排列（即使新植物不是过度优势），对授粉和植物繁殖成功具有重要的功能影响。我们的研究建立了网络结构与授粉和植物繁殖成功之间的联系，