Higher levels of biodiversity seem to reduce the risk of extinction in birds

A new study from the University of Michigan has found that higher levels of biodiversity – the enormous variety of life on Earth and the species, traits and evolutionary history they represent – appear to reduce the risk of extinction in birds.

Previous research has established that biodiversity is associated with predictable short-term outcomes: diverse systems are less prone to invasion, have more stable productivity, and may be more disease resistant.

The new study, published online Feb. 24 in Ecology Letters and led by evolutionary biologist and ornithologist Brian Weeks of the UM School for Environment and Sustainability, found another positive finding in potentially reduced extinction rates.

The study used a new dataset collected by researchers using specimens from natural history museums that covers more than 99% of all bird species worldwide. Although the practice of using natural history museum specimens is common, this is the first time that there has been a comprehensive data set on the functional traits of all birds.

The researchers used the data to measure the diversity of birds around the world, including the species present in a community, their evolutionary relationships and their functional traits. They then used structural equation modeling to characterize the relationship between diversity and extinction risk.

According to the study, diversity is associated with lower levels of contemporary extinction risk in birds. The study attributes this to diverse communities providing a safe haven for endangered species. Species characteristics (eg, large body size, poor dispersal ability, or small range) may make them more susceptible to extinction. However, it appears that the benefits of living in a diverse community protect these extinction-prone species, allowing more of them to persist.

The results reveal the importance of protecting diversity, according to the authors.

“While we know that biodiversity affects ecosystem functioning in predictable ways, it’s less clear how these biodiversity-ecosystem functioning relationships affect extinction risk on longer time scales,” Weeks said. “Our results suggest that conserving biodiversity is not just a conservation goal, but is also likely a necessary component of effective conservation interventions.”

The researchers also concluded that maintaining biodiversity-rich communities may be a more cost-effective approach to preventing extinction, as single-species conservation interventions are costly.

The other study authors are Shahid Naeem of Columbia University, Jesse Lasky of Pennsylvania State University and Joseph Tobias of Imperial College London. The collection of data on bird characteristics was supported by the UK Natural Environment Research Council.

Written by Nayiri Mullinix, UM School for Environment and Sustainability

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