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  • A global analysis of avian island diversity–area relationships in the Anthropocene
    Publication . Matthews, Thomas J.; Wayman, Joseph P.; Whittaker, Robert J.; Cardoso, Pedro; Hume, Julian P.; Sayol, Ferran; Proios, Konstantinos; Martin, Thomas E.; Baiser, Benjamin; Borges, Paulo A. V.; Kubota, Yasuhiro; dos Anjos, Luiz; Tobias, Joseph; Soares, Filipa C.; Si, Xingfeng; Ding, Ping; Mendenhall, Chase D.; Sin, Yong Chee Keita; Rheindt, Frank E.; Triantis, Kostas; Guilhaumon, François; Watson, David M.; Brotons, Lluís; Battisti, Corrado; Chu, Osanna; Rigal, François
    Research on island species–area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity–area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have ‘re-calibrated’ the IDARs such that they resemble the historic period prior to recent extinctions.
  • Land-use change interacts with island biogeography to alter bird community assembly
    Publication . Zhao, Yuhao; Mendenhall, Chase D.; Matthews, Thomas J.; Wang, Duorun; Li, Wande; Liu, Xiangxu; Tang, Shupei; Han, Peng; Wei, Guangpeng; Kang, Yi; Wu, Chenxiao; Wang, Rui; Zeng, Di; Frishkoff, Luke O.; Si, Xingfeng
    Anthropogenic activities have reshaped biodiversity on islands worldwide. However, it remains unclear how island attributes and land-use change interactively shape multiple facets of island biodiversity through community assembly processes. To answer this, we conducted bird surveys in various land-use types (mainly forest and farmland) using transects on 34 oceanic land-bridge islands in the largest archipelago of China. We found that bird species richness increased with island area and decreased with isolation, regardless of the intensity of land-use change. However, forest-dominated habitats exhibited lower richness than farmland-dominated habitats. Island bird assemblages generally comprised species that share more similar traits or evolutionary histories (i.e. functional and/or phylogenetic clustering) than expected if assemblages were randomly assembled. Contrary to our expectations, we observed that bird assemblages in forest-dominated habitats were more clustered on large and close islands, whereas assemblages in farmland-dominated habitats were more clustered on small islands. These contrasting results indicate that land-use change interacts with island biogeography to alter the community assembly of birds on inhabited islands. Our findings emphasize the importance of incorporating human-modified habitats when examining the community assembly of island biota, and further suggest that agricultural landscapes on large islands may play essential roles in protecting countryside island biodiversity.