Dissertation Research: Allochthonous inputs as invasion mechanism of C. nucifera

生物入侵是我们面临的最紧迫的保护挑战之一。这些入侵目前被认为是全球生物多样性丧失的主要驱动因素之一。这项研究考察了一种不寻常的入侵的机制和影响：在整个太平洋引入椰子树。具体来说，这项工作着眼于这种棕榈的相对丰度和海鸟之间的负相关关系。海鸟不会以椰子树为栖息地；因此，棕榈树入侵的岛屿耗尽了这些鸟类通常从海洋带到陆地的营养物质。由于这些岛屿上的原生树种已经适应了通常由鸟类创造的更高营养条件，它们无法在这些新的、更缺乏营养的条件下竞争和再生。因此，海鸟数量的减少最终导致了椰树的入侵。这项研究还考察了这种入侵的其他潜在反馈，例如对入侵森林中本地物种种子或幼苗的捕食增加。这项工作对保护科学和管理具有重要的应用价值。在全球范围内，通过增加对入侵机制广度的了解，这项工作将为管理入侵物种和防止其未来传播提供最佳方法。就区域而言，它将就如何在太平洋地区管理这种广泛使用的作物提供切实可行的建议。最后，通过展示海鸟在维护本地物种方面的作用，它将扩大我们对海鸟及其保护重要性的认识。

Biological invasions are one of our most pressing conservation challenges. These invasions are currently considered to be one of the major drivers of global biodiversity loss, among other ills. This research examines the mechanisms and effects of one unusual invasion: the introduction of the coconut palm throughout the Pacific. Specifically, this work looks at the negative association between the relative abundances of this palm and of seabirds. Seabirds will not use the coconut palm as habitat; therefore palm-invaded islands become depleted in the nutrients these birds usually bring from the ocean to the land. Because the tree species native to these islands are adapted to the higher nutrient conditions usually created by the birds, they can no longer compete and regenerate in these new, more nutrient deprived conditions. The seabird decline thus ultimately results in an invasion spiral of coconut palms. This research also examines other potential feedbacks in this invasion, such as increases to predation on native species seeds or seedlings in invaded forests. This work has important applications to conservation science and management. On a global scale, by increasing knowledge of the breadth of invasion mechanisms, this work will provide insight into the best way to manage invasive species and prevent their future spread. Regionally, it will provide tangible recommendations about how this widely used crop should be managed in the Pacific. Finally, by demonstrating the role seabirds play in maintaining native species, it will expand our knowledge about the importance of seabirds and their conservation.