Imagine yourself lounging on a sandy beach, gazing out at the breathtaking view of Lombok just northeast of Bali. What you might not realize is that you’re traversing an invisible boundary known as the Wallace Line.
Named after the British naturalist Alfred Russel Wallace, this line marks a division between the plants and animals of nearby islands due to ancient geological shifts and evolutionary processes. But does it hold significance in today’s world?
Researchers from the Department of Ecology and Evolution at UNIL have delved into this question, particularly focusing on ants. Led by Lucie Aulus-Giacosa, they’ve explored how human activities, such as global trade and tourism, are altering the habitats of ant species worldwide.
“A lot of previous studies concentrated on snails, but our work on ants, which constitute a significant portion of Earth’s animal life, has uncovered some unexpected findings,” says Aulus-Giacosa. “We’ve observed that even a small influx of non-native ant species can significantly disrupt ecosystems, impacting not only the ants we’ve studied but the entire ant community.”
In simpler terms, tropical regions are becoming more alike. Whether you’re in Australia, Africa, or South America, you’re increasingly likely to encounter similar ant species. Cleo Bertelsmeier, the project’s lead, believes this would certainly astonish Wallace!
This homogenization of species is due to the rich biodiversity found in the tropics. These regions not only generate a plethora of species but also facilitate their adaptation to similar climates elsewhere. “It’s concerning to acknowledge that in just 200 years, we’ve disrupted millions of years of ant evolution,” remarks Bertelsmeier, highlighting the profound impact humans are having on Earth’s biodiversity.
The research paints a troubling picture: over half of the world’s ant communities are becoming more uniform, with tropical regions and islands bearing the brunt of these changes. These areas, with their unique ecosystems, are particularly susceptible to human influence, sparking concerns about the fate of distinct species.
Looking ahead, the researchers aim to focus on islands, where tourism and trade frequently introduce invasive species that harm local wildlife. “We’re striving to understand why islands are experiencing more pronounced changes,” explains Aulus-Giacosa, underscoring the crucial need to safeguard these fragile ecosystems.