It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, April 22, 2025
Big brains and big ranges might not save birds from climate change
Global bird sightings from citizen scientists and view into “climate niches” reveals unexpected risks for some birds.
(a) The breeding range for the Bohemian waxwing (purple) extends over a large swath of the Arctic, while the chestnut-crowned laughingthrush (red) inhabits a much smaller arc in Asia centered on Nepal and Bhutan. (d) Yet the waxwing inhabits a much smaller and more extreme range of climate conditions than the laughingthrush, suggesting the waxwing may be at greater risk from climate change than previously thought.
Credit: Carlos Botero/University of Texas at Austin.
Biologists have long debated why some plants and animals can adjust to a wide range of climates, while others can’t. Understanding why could help conservation managers and decision makers identify which species are most vulnerable to climate change.
A new study in Nature Communications by researchers at The University of Texas at Austin evaluated global distribution maps and other data for about 1500 bird species and found some surprising patterns. For example, the researchers found that some species that breed over large geographic areas can still be adapted to a fairly narrow range of climates, making them more vulnerable to climate change than previously thought. Take for example the Arctic, which occupies a considerable portion of Earth’s landmass but exhibits very similar climate patterns all over.
“Because that region is so big, species that occupy it tend to have large populations and large geographic range sizes—two characteristics that are often associated with lower extinction risks,” said Carlos Botero, an associate professor of integrative biology and senior author of the new study. “The problem here is that because many of those species are adapted to a very narrow range of climates, those seemingly large populations can be quite susceptible to collapse when climate patterns begin to change.”
For example, the breeding range for the Bohemian waxwing, a bird well known to North American and European birders, extends over a large swath of the Arctic, while the chestnut-crowned laughingthrush inhabits a much smaller arc in Asia centered on Nepal and Bhutan. Yet the waxwing inhabits a much smaller and more extreme range of climate conditions than the laughingthrush, suggesting the waxwing may be at greater risk from climate change than previously thought.
The researchers also found that species with larger brains (relative to their body size) tend to be adapted to narrow climate niches, which suggests they could also be more vulnerable to climate change than previously thought. A climate niche is the range of different climate conditions (think temperature, precipitation and how predictably these two vary over time) that a species can thrive in.
“Larger brain sizes correlate with more flexible behavior, so big-brained birds are usually expected to be more adaptable,” Botero said. “However, it turns out that many big-brained birds are climate specialists—meaning that they have evolved to thrive in very particular climate types and may therefore also be more vulnerable to climate change than we expected.”
Botero carried out the study with corresponding author and former UT postdoctoral researcher João Fabrício Mota Rodrigues.
For this study, Rodrigues and Botero used avian range maps estimated from hundreds of thousands of direct observations by citizen scientists reported through eBird. This successful partnership between birdwatchers and scientists is providing highly accurate representations of where different species occur in space and is enabling scientists to answer questions that were simply impossible to address before.
The research team also created a system for describing all the climate types found on Earth in terms of two factors: “temperature harshness,” a value that increases with colder, more variable and less predictable temperatures—and “xeric harshness,” which increases with lower, more variable and less predictable precipitation. Then they created a 2D “climate space” map that shows how much of Earth’s land surface corresponds to each possible combination of these two factors. Places that are less harsh in temperature and precipitation are near the center, while places that are harsher in one or both factors are farther out.
Finally, for each species, they mapped the range of climates that species tends to occupy onto the climate space map to see where and how large their climate niche is. Birds with a smaller and more extreme climate niche tend to be at higher risk from climate change.
Botero said this study highlights why the usual way of assessing risk for a species, which typically involves a checklist of individual factors, misses the complexity of underlying patterns and contradictions.
“We need to stop looking at individual risk factors in isolation, but evaluate how these complex factors combine,” Botero said. “Sometimes, it is the unexpected interactions that matter most.”
This research was made possible by support from the National Science Foundation.
Study Reveals Factors Driving Range Expansion in Lesser Goldfinches
FOR IMMEDIATE RELEASE
April 23, 2025
ITHACA, N.Y. — New research published in the journal Ornithology shows that Lesser Goldfinches, a small songbird traditionally found in the Southwest, are expanding their range northward through the Pacific Northwest at an unprecedented rate, providing insights into how species adapt to environmental change.
Researchers from Washington State University and the Cornell Lab of Ornithology analyzed data from birdwatchers participating in two initiatives from the Cornell Lab — Project FeederWatch and eBird — to track the species' movement. The study found that Lesser Goldfinch populations increased dramatically in Washington (110.5%), Idaho (66.3%), and Oregon (16.9%) between 2012 and 2022.
"When I first arrived in eastern Washington I was pretty new to birding and Lesser Goldfinches were new to me. I was seeing groups of 30 or 40 at a time and I sort of assumed that was normal, until I started meeting local birders who said, '10 years ago we never had Lesser Goldfinches,’ so I started to investigate what was going on,” said Mason Maron, lead author and graduate of Washington State University.
"What's fascinating is how these birds are adapting to human-modified landscapes," said Maron. "They're not just moving north randomly — they're following specific corridors, particularly along rivers and through urban areas where temperatures are warmer and where both native and non-native plants provide food."
The research identified maximum annual temperature, annual rainfall, urban development, and proximity to major rivers as key factors associated with the northward expansion. Although the authors noted Lesser Goldfinches appear at backyard bird feeders often, when they looked at how bird feeders might affect establishment, surprisingly, bird feeders played a minimal role in establishing new populations.
"There wasn't really a significant association with bird feeders," Maron said. The first individuals to arrive in a new area might go to feeders because they provide easy to access food, but Maron explained, “it's not going to be enough to sustain a whole population."
Rivers emerged as crucial corridors for expansion. "These rivers carry weedy plants and seeds really well," said Maron. "We, as people, like to live along the river, so we disturb the soil and that really creates this sort of chain of the perfect conditions for them."
Once established in new areas, the goldfinch populations remain stable. "Our results are suggestive of this species being able to pretty rapidly colonize new environments," said Jordan Boersma, co-author and research associate at the Cornell Lab of Ornithology. "It's not just that Lesser Goldfinches are exploring these new areas...they are moving in and typically turning into stable populations or even increasing populations."
The Lesser Goldfinches might be shifting north in response to climate and habitat changes reported by this study, and indeed, the Cornell Lab of Ornithology’s eBird Status and Trends project indicates that Lesser Goldfinches are declining in the southern parts of their range.
While this expansion shows some species can adapt to environmental change, Maron cautions against broad generalizations: "What it really shows is that we know a lot of species are declining and struggling because of these changes. Some species can survive and adapt and do better, but it's not necessarily a trade-off."
“This species has proven remarkably adaptable to environmental change," said Boersma. "Understanding how birds like the Lesser Goldfinch respond to climate change and urbanization helps us predict how other species might also be impacted."
"When we understand how wildlife responds to environmental change, we're better equipped to make informed decisions about urban planning, conservation, and climate adaptation," said Maron.
The research was made possible by thousands of participants who contributed observations through Project FeederWatch and eBird. These participatory science programs provide researchers with valuable long-term data about bird populations across North America.
###
Reference: M. W. Maron, E. I. Greig, and J. Boersma. (2025). Range Expansion Dynamics of the Lesser Goldfinch (Spinus psaltria) in the Pacific Northwest. Ornithology: 10.1093/ornithology/ukaf013
Editors: Download images. The use of this material is protected by copyright. Use is permitted only within stories about the content of this release. Redistribution or any other use is prohibited without express written permission of the Cornell Lab of Ornithology or the copyright owner.
Media Contact:
Kathi Borgmann, Cornell Lab of Ornithology, (607) 254-2137, klb274@cornell.edu
No comments:
Post a Comment