Oct. 4 () –
The human-caused extinction of hundreds of bird species over the past 130,000 years has resulted in the loss of approximately 3 billion years of unique evolutionary history.
New research led by the University of Birmingham, published in Science, highlights how human influence has led to substantial reductions in avian functional diversity: a measure of the variety of different roles and functions that birds play within the environment.
From the well-documented dodo to the recent Kaua’i’o’o songbird declared extinct in 2023, scientists currently have evidence that at least 600 bird species have become extinct as a result of humans since the late Pleistocene, when modern humans began to spread around the world.
Using the most comprehensive data set to date of all known bird extinctions during the Late Pleistocene and Holocene, the paper looks beyond the number of extinctions and discusses the broader implications for the planet.
Lead author Dr. Tom Matthews, from the University of Birmingham, explained in a statement: “The large number of bird species that have become extinct is, of course, a large part of the extinction crisis, but what we must also keep in mind is that each species has a job or function within the environment and, Therefore, it plays a really important role in its ecosystem.
“Some birds control pests by eating insects, scavengers recycle dead matter, others eat fruit and disperse seeds, allowing more plants and trees to grow, and some, like hummingbirds, are very important pollinators. When those species die, the important role they play (functional diversity) dies with them.
“In addition to functional diversity, each species also has a certain amount of evolutionary history, so when that species goes extinct, it’s basically like cutting a branch off the tree of life and all that associated phylogenetic diversity is lost as well.”
The research found that the scale of anthropogenic bird extinctions to date has resulted in a loss of approximately 3 billion years of unique evolutionary history and 7% of global avian functional diversity, an amount significantly higher than expected based on the number of extinctions.
Given the wide range of important ecological functions played by birds, the loss of avian functional diversity in particular is likely to have had far-reaching implications. These post-extinction after-effects include reduced pollination of flowers, reduced seed dispersal, breakdown of top-down control of insect populations, including many pests and disease vectors, as well as an increase in disease outbreaks due to reduced carrion consumption.
Furthermore, the reduction in global birdlife documented in the research will likely affect the ability of many plant species to track current and future climate change.
Dr. Matthews concludes: “These results are a timely reminder that the current extinction crisis It’s not just about the number of species.
“By identifying declines in bird functional and phylogenetic diversity driven by human actions, our findings highlight the urgent need to understand and predict the impacts of past anthropogenic extinctions on ecosystem function to prepare for the magnitude of expected future loss.” of the 1,000 bird species expected to become completely extinct in the next two centuries.
“This information is vital for setting effective targets for global conservation strategies, as well as ecosystem restoration and wildlife reintroduction efforts.”
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