Due to the extinction of many bird species, the variety of roles they played in the ecosystem was eliminated

Pollination, waste removal, pest control and many other services that birds provide us have been affected due to the extinction of many species

Extinctions caused by human activity have wiped out significant species of birds and worse their functional diversity, leading to the loss of 3 billion years of evolution and severely impacting ecosystem health, highlighting the urgent need for conservation actions.

Human-caused avian extinctions over the past 130,000 years have reduced the functional diversity of birds and erased 3 billion years of evolution, harming pollination, pest control, and ecosystems. Understanding these losses is key to future conservation.

A new study published in the journal Science reveals that the extinction of hundreds of bird species by humans over the past 130,000 years has significantly reduced the functional diversity of birds—that is, the variety of roles birds play in ecosystems—and resulted in the loss of approximately 3 billion years of unique evolutionary history.

While humans have been causing a global decline in species diversity for thousands of years, the consequences of past extinctions on other dimensions of biodiversity have been poorly understood. New research conducted by the University of Birmingham highlights the serious consequences of the ongoing crisis in biodiversity and the urgent need to identify the ecological functions that are disappearing due to extinctions.

Extinctions of famous bird species and their wide-ranging effects

From the well-documented Dodo to the Kauai ʻōʻō songbird declared extinct in 2023, scientists have evidence that more than 600 bird species have been wiped out by human activity since the Late Pleistocene, when modern humans began to spread around the world. Using the most comprehensive database to date of all known avian extinctions during the Late Pleistocene and Holocene, the paper "The Loss of Avian Functional and Phylogenetic Diversity from Anthropogenic Extinctions" examines the far-reaching implications for the planet beyond just the number of extinctions.

Dr. Tom Matthews from the University of Birmingham, lead author of the study, explained: "The number of extinct species is of course an important part of the extinction crisis, but what we need to focus on is that each species plays a role or function in the environment and therefore has an important role in its ecosystem. Some birds control pests by eating insects, scavenging birds recycle dead matter, others eat fruit and spread the seeds and allow more plants and trees to grow, and some, like hummingbirds, are important pollinators. When these species go extinct, their important role (functional diversity) goes extinct with them.

"In addition to functional diversity, each species also carries a certain amount of evolutionary history, so when the species becomes extinct, it's basically like cutting a branch from the tree of life, and all the phylogenetic diversity associated with it is also lost."

Consequences of extinctions on ecosystems

The study found that the extent of human avian extinctions so far has resulted in the loss of approximately 3 billion years of unique evolutionary history, and approximately 7% of the functional diversity of the world's birds - a significantly greater amount than would be expected given the number of extinctions. Given the wide variety of important ecological functions performed by birds, the loss of functional diversity of birds in particular may have far-reaching effects. The post-extinction consequences include a reduction in flower pollination, reduced seed dispersal, impairment of natural control of insect populations—including many pests and disease carriers—as well as an increase in disease outbreaks as a result of reduced carrion consumption. In addition, the reduction of bird populations in the world documented in the study may affect the ability of many plant species to deal with climate change in the present and in the future.

Dr. Matthews concludes: "These findings are a timely reminder that the current extinction crisis is not only related to the number of species. By identifying declines in avian functional and phylogenetic diversity resulting from human actions, our findings highlight the urgent need to understand and predict the effects of past anthropogenic extinctions on ecosystem functions to prepare for the expected loss in the future, when approximately 1,000 additional bird species are expected to become extinct over the next two centuries . This information is essential for setting effective targets for global conservation strategies, as well as for ecological restoration and restoration efforts."

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