Dataset of "Crucial factors determining colonisation patterns of bird species on oceanic islands in the Anthropocene"

Dataset of "Crucial factors determining colonisation patterns of bird species on oceanic islands in the Anthropocene." Details of the dataset are provided in the README.txt.
Abstract
Biodiversity on insular ecosystems has been affected by human activities in the Anthropocene. Biological communities in oceanic islands are shaped by colonisation and extinction of species. Although many ecological studies conducted on oceanic islands have focused on species extinction due to human activities, studies investigating the effects of human activities on species colonisation via natural dispersals are limited. Here, we quantified the relative effects of natural and anthropogenic factors on natural colonisation of bird species on oceanic islands. We investigated colonised bird species richness by comparing bird communities surveyed between 2017 and 2021 with those surveyed between 1970 and 1973 in 261 grids on ten islands of the Izu Islands, central Japan. We quantified the relative contributions of 13 factors on the colonised species richness using the stepwise model selection of generalised linear models and hierarchical partitioning. Colonised species were recorded in 78 grids. We found that the species composition of the nearest island in the 1970s, used as a proxy for a potential source of colonisation, had the highest effect among the factors. Landscape composition related to human activities, the proportion of human settlement area, had the second-highest effect. Specifically, the proportion of human settlement area was positively associated with colonised species richness. We empirically suggest that community structures on the nearest island in the past have impacted natural colonisation of species on a target island. Moreover, our findings highlight that human-induced landscape transformations in archipelagos facilitate the natural colonisation of several species on oceanic islands that prefer disturbed habitats.