Understanding the impacts of global change on ecological communities is a major challenge in modern ecology. The gain or loss of particular species and the disruption of key interactions are both consequences and drivers of global change that can lead to the disassembly of ecological networks. We examined whether the disruption of a hummingbird–mistletoe–marsupial mutualism by the invasion of non-native species can have cascading effects on both pollination and seed dispersal networks in the temperate forest of Patagonia, Argentina. We focused on network motifs, subnetworks composed of a small number of species exhibiting particular patterns of interaction, to examine the structure and diversity of mutualistic networks. We found that the hummingbird–mistletoe–marsupial mutualism plays a critical role in the community by increasing the complexity of pollination and seed dispersal networks through supporting a high diversity of interactions. Moreover, we found that the disruption of this tripartite mutualism by non-native ungulates resulted in diverse indirect effects that led to less complex pollination and seed dispersal networks. Our results demonstrate that the gains and losses of particular species and the alteration of key interactions can lead to cascading effects in the community through the disassembly of mutualistic networks.

中文翻译：

---

基石相互作用的破坏侵蚀了授粉和种子传播网络

了解全球变化对生态群落的影响是现代生态学的一项重大挑战。特定物种的得失和关键相互作用的破坏既是全球变化的后果，也是可能导致生态网络瓦解的驱动因素。我们检查了蜂鸟 - 槲寄生 - 有袋动物共生受到非本地物种入侵的破坏是否会对阿根廷巴塔哥尼亚温带森林的授粉和种子传播网络产生级联影响。我们专注于网络主题，即由少数物种组成的子网络，表现出特定的相互作用模式，以检查互惠网络的结构和多样性。我们发现蜂鸟-槲寄生-有袋动物共生通过支持高度多样性的相互作用增加授粉和种子传播网络的复杂性，在群落中发挥着关键作用。此外，我们发现非本地有蹄类动物对这种三方共生关系的破坏导致了多种间接影响，从而导致授粉和种子传播网络的复杂性降低。我们的研究结果表明，特定物种的得失和关键相互作用的改变可以通过互惠网络的分解导致群落中的级联效应。我们发现，非本地有蹄类动物对这种三方共生关系的破坏导致了多种间接影响，从而导致授粉和种子传播网络的复杂性降低。我们的研究结果表明，特定物种的得失和关键相互作用的改变可以通过互惠网络的分解导致群落中的级联效应。我们发现，非本地有蹄类动物对这种三方共生关系的破坏导致了多种间接影响，从而导致授粉和种子传播网络的复杂性降低。我们的研究结果表明，特定物种的得失和关键相互作用的改变可以通过互惠网络的分解导致群落中的级联效应。