SAEF scientists have revealed that bird uniqueness increases the closer you get to Antarctica. The ground-breaking discovery demonstrates that endemism (when a species is unique to a location and found nowhere else on Earth) increases in a linear pattern from the Arctic to the Antarctic.
The findings have a significant implication for global conservation. Currently, conservation efforts are primarily focused on areas with a high number of species. This study shows that in order to protect planet-wide bird diversity conservation efforts must expand to also safeguarding places where endemic species have evolved and exist nowhere else on Earth.
The unexpected pattern is driven by the increasingly smaller and discontinuous availability of land in the south–the tip of South America, South Africa, and southern Australia– separated by vast expanses of ocean. The study, published in Nature Communications, challenges widely accepted science on global diversity patterns and demonstrates a need to protect hotspots of endemism.
The findings were made by two SAEF scientists, Dr Matthias Dehling and Professor Steven Chown, who had a hunch about the importance of Antarctic birds such as the wandering albatross and the emperor penguin. They were also bugged by the fact that these unique species were often excluded from global diversity analyses due to the relatively low number of species inhabiting the Antarctic region.
“This pattern is both completely crazy and obvious! It highlights how, while the total number of bird species might be lower in the south, the proportion of those species found nowhere else on Earth skyrockets,” said Professor Chown.
“In the past, tiny islands in the middle of the Southern Ocean, like Macquarie Island, were largely ignored from global diversity studies, but they have fostered the evolution of highly unique birds—such as albatrosses, petrels, and penguins.”
The most commonly accepted pattern of diversity is that species richness (the number of species found in a location) decreases from the tropics to the poles. This has meant that global conservation efforts have typically focused on areas of high species richness.
To make the discovery, the team harnessed a novel method developed by Dr Dehling to describe the role of species within ecosystems and applied them to compare species communities. They compiled global datasets on bird distribution ranges, functional traits (such as body size or beak shape), and evolutionary relationships, and then projected their range sizes onto a world map divided into grids, revealing the north-to-south pattern.
“This new understanding of global bird diversity has important implications for conservation, as it highlights that environmental change will impact birds in the two hemispheres very differently,” said Dr Dehling, who led the study.
“In the northern hemisphere, birds can potentially move to more suitable habitats by going either east/west or north/south. Meanwhile, in the southern hemisphere, where land masses are more isolated and divided by vast expanses of ocean, birds have much more limited options. This makes them more vulnerable to climate change and environmental disturbances, such as land clearing, and necessitates a greater focus on their protection.”
Currently, global conservation efforts seek to find and protect areas that make unique contributions to global biodiversity. This study demonstrates that factoring in hotspots of endemism will be crucial for maintaining global bird diversity.
It also demonstrates that if you are a keen birder, knowing where these hotspots are can also increase the uniqueness of your bird-watching experience.
Read more:
Dehling, D. M. & Chown, S. L. (2025) Global increase in the endemism of birds from north to south. Nature Communications, 16(1), 6251. https://doi.org/10.1038/s41467-025-61477-8
