The extinction of numerous bird species due to human activities over the past 130,000 years has significantly diminished avian functional diversity, which refers to the various roles and responsibilities birds fulfill in their ecosystems. This decline has resulted in a staggering loss of nearly 3 billion years of unique evolutionary history, as highlighted in a recent study.
The extinction of numerous bird species due to human activities over the past 130,000 years has significantly diminished avian functional diversity, which refers to the various roles and responsibilities birds fulfill in their ecosystems.
This decline has resulted in a staggering loss of nearly 3 billion years of unique evolutionary history, according to a newly published study in Science.
While humans have been responsible for a global decline in species diversity for thousands of years, the effects of historical extinctions on other aspects of biodiversity remain largely unexamined. Research from the University of Birmingham sheds light on the severe impacts of the ongoing biodiversity crisis and emphasizes the urgent necessity to recognize the ecological functions being lost due to extinction.
From the well-known Dodo to the recently extinct Kauaʻi ʻōʻō songbird declared extinct in 2023, scientists have documented at least 600 bird species that have vanished because of human influence since the Late Pleistocene, when modern humans began populating the globe. Using the most comprehensive dataset available on bird extinctions during the Late Pleistocene and Holocene, the paper titled ‘The global loss of avian functional and phylogenetic diversity from anthropogenic extinctions’ explores the broader consequences of these extinctions on our planet.
Lead researcher Dr. Tom Matthews from the University of Birmingham stated: “While the sheer number of bird species that have gone extinct is significant, it’s equally important to recognize that each species fulfills a specific role in its environment, contributing to the ecosystem’s overall health. Certain birds help control pest populations by consuming insects, scavenger species recycle decomposed matter, others eat fruit and aid in seed dispersal for plant growth, and birds like hummingbirds serve as critical pollinators. When these birds disappear, their ecological functions also vanish, leading to a decrease in functional diversity.”
“Moreover, each species holds a unique segment of evolutionary history. Therefore, when one species goes extinct, it’s akin to cutting a branch off the tree of life, resulting in the loss of related phylogenetic diversity as well.”
The study revealed that the extensive bird extinctions caused by humans have led to a loss of around 3 billion years of unique evolutionary heritage and diminished 7% of the world’s avian functional diversity — a much larger impact than anticipated in relation to the number of extinctions. Given the diverse ecological roles of birds, the decline in avian functional diversity is likely to have significant repercussions. The consequences include decreased flower pollination, reduced seed dispersal, a breakdown in the control of insect populations (including pests and disease carriers), and increased disease occurrences due to fewer scavengers consuming carrion. Additionally, the reduction of bird populations recorded in this research may hinder many plant species’ ability to adapt to current and future climate changes.
Dr. Matthews concluded: “These findings serve as a crucial reminder that the ongoing extinction crisis extends beyond species counts. By recognizing the declines in avian functional and phylogenetic diversity due to human activities, our research emphasizes the pressing need to comprehend and anticipate the effects of historical human-induced extinctions on ecosystem functions. This understanding is essential for preparing for the potential loss of approximately 1,000 bird species predicted to go extinct in the next two centuries. Such information is critical in establishing effective global conservation targets, as well as strategies for ecosystem restoration and rewilding initiatives.”
