Lead author of the study, Ferran Sayol, a research fellow in Genetics and Evolution at University College London (UCL), highlights the extent of change brought about by human actions: “Humans have drastically changed bird communities, not only by driving animals to extinction but also by introducing species into new habitats across the globe. There has been some debate as to whether introduced species might replace the roles of the extinct species, thus maintaining functional diversity within the ecosystem; here, we found that is unfortunately not the case.”
“Some of the extinct species had a role in their ecosystem that has not been replaced by other birds,” elaborated Sayol. “For example, some giant flightless species, like the moas of New Zealand and the elephant birds of Madagascar, were probably acting like large terrestrial herbivores as grazers, similar to ungulates like cattle and sheep on the continents, before being driven extinct by humans.”
The ramifications of bird extinctions extend beyond individual species. Functions like pollination and seed dispersal, essential for ecosystem health, are also at risk. The study found that as native birds go extinct and non-native bird species are introduced, different archipelagos are becoming increasingly similar in terms of trait diversity.
Co-author Tim Blackburn, a professor of zoology at UCL, noted that certain groups of birds, like parrots and starlings, have been particularly successful at establishing themselves outside their native areas, contributing to the homogenization of island bird communities.
The study’s implications emphasize the urgency of conservation efforts focused on preserving functionally distinct threatened species. Alex Pigot, a senior research fellow at UCL and co-author of the study, concludes, “Our findings add to evidence that conservation efforts should be focused on preserving functionally distinct threatened species, to stem the tide of harmful losses to biodiversity that are driven by human actions.”
