According to a study published in the journal Science Advances, the loss of bird species due to human factors such as habitat destruction or climate change is causing a decline in functional diversity on islands globally. The research reveals that even if non-native bird species take over the extinct species’ role, their contribution cannot compensate for the loss. This is a concerning finding as islands are important ecosystems with unique biodiversity.
A recent study by Ferran Sayol, a research fellow in Genetics and Evolution at University College London (UCL), revealed that humans have significantly impacted bird communities by driving some species to extinction and introducing others into new habitats worldwide. The research aimed to determine whether introduced species could replace the functions of extinct species, preserving functional diversity within ecosystems. The study examined 1,302 bird species from nine archipelagos, including 265 extinct species and 355 newly introduced species from 143 different species. The findings showed that island bird communities were more diverse morphologically before human arrival, and human-driven extinctions disproportionately affected some species, resulting in the loss of specific ecological roles.
Sayol stated that there were certain extinct bird species that played a crucial role in their ecosystem, which cannot be fulfilled by any other birds. Earlier, before humans drove some large flightless animals like the moas of New Zealand and elephant birds of Madagascar to extinction, they were behaving as significant terrestrial herbivores and grazers like ungulates such as sheep and cattle on other continents. The extinction of birds may lead to the loss of other vital functions such as pollination and seed dispersal, which can have severe negative impacts on other species.
According to the findings of the study, it was observed that if local birds become extinct and foreign birds of the same species are introduced in multiple areas, then the variety of traits in different regions is slowly becoming similar. The research co-author and UCL professor of zoology, Tim Blackburn, mentioned that some bird groups such as parrots and starlings have been successful in establishing themselves outside their natural habitats. As a result, islands are becoming more uniform in terms of bird species and traits due to the colonization by the same types of birds.