Data from: Non-random patterns of invasion and extinction reduce phylogenetic diversity in island bird assemblages

Anthropogenically driven changes in bird communities on oceanic islands exemplify the biotic upheaval experienced by island floras and faunas. While the influence of invasions and extinctions on species richness and beta-diversity of island bird assemblages have been explored, little is known about the impact of these invasions and extinctions on phylogenetic diversity. Here we quantify phylogenetic diversity of island bird assemblages resulting from extinctions alone, invasions alone, and the combination of extinctions and invasions in the historic time period (1500 CE to the current), and compare it to the expected phylogenetic diversity that would result if these processes involved randomly selected island bird species. We assessed phylogenetic diversity and structure at the scale of the island (n =152), the archipelago containing the islands (n=22), and the four oceans containing the archipelagos using three measures. We found that extinction, invasion, and the combination of invasion and extinction generally resulted in lower phylogenetic diversity than expected, regardless of the spatial scale examined. We conclude that extinction and invasion of birds on islands are non-random with respect to phylogeny and that these processes generally leave bird assemblages with lower phylogenetic diversity than we would expect under random invasion or extinction.

大洋岛屿上鸟类群落受人为活动驱动的变化，堪称岛屿植物群与动物群所经历的生物剧变的典型范例。尽管学界已针对物种入侵与灭绝对岛屿鸟类集合群的物种丰富度及β多样性（beta-diversity）的影响展开探讨，但目前对于这两类过程如何作用于系统发育多样性（phylogenetic diversity），仍缺乏足够的认知。本研究量化了公元1500年至今的历史时段内，仅经历灭绝、仅经历入侵，以及同时经历灭绝与入侵的岛屿鸟类集合群的系统发育多样性，并将其与若这些过程随机选取岛屿鸟类物种时所预期得到的系统发育多样性进行对比。本研究采用3种测度指标，分别在岛屿尺度（样本量n=152）、包含这些岛屿的群岛尺度（样本量n=22）以及涵盖这些群岛的四大洋尺度上，评估了鸟类集合群的系统发育多样性及其结构特征。研究结果表明，无论在哪一种空间尺度下，鸟类灭绝、入侵以及二者共同作用，通常都会导致系统发育多样性低于预期水平。本研究得出结论：岛屿鸟类的灭绝与入侵过程在系统发育层面并非随机发生，且相较于随机入侵或随机灭绝的情形，这两类过程通常会使鸟类集合群的系统发育多样性降至更低水平。