Fiji’s Native Ants Decline: 79% of Endemic Species in Trouble

A new genomic study reveals that nearly 80% of indigenous ant species in Fiji are facing population declines, underscoring how island biodiversity is especially vulnerable to human impact.

Researchers from the Okinawa Institute of Science and Technology (OIST) used DNA from specimens collected over centuries in museum collections to reconstruct the history of Fiji’s ant communities. These specimens, analyzed via “museumomics,” allowed scientists to trace both long-term trends and more recent changes in species numbers. They found that the most severe declines in endemic ant species correlate with European contact, colonial expansion, modern trade, and agricultural intensification over the past few hundred years.

Meanwhile, ant species introduced by humans are booming. The team identified 65 separate colonization events—including both natural arrivals from millennia ago and recent invasions tied to global trade—showing that non-native species have gained a strong foothold in Fiji. The decline is particularly marked among species found only in Fiji; many of these have evolved sensitive traits, making them poorly equipped to cope with rapid environmental changes and invasive species pressures.

Because islands like Fiji are relatively isolated, they can act like early warning systems for biodiversity collapse. The research shows that museum collections are more than relics: they’re powerful tools for tracking ecological change over long time frames. The authors suggest that better monitoring and conservation efforts—drawing on both historic data and current field observations—are essential to preserving insect biodiversity. The study adds to mounting evidence of an “insect apocalypse” underway, especially in tropical island ecosystems, where human activity and ecosystem fragility collide.

Key Takeaways:

About 79% of Fiji’s endemic ant species are declining, with sharp drops corresponding to colonial era and modern agriculture.

Non-native ant species (introduced more recently) are increasing significantly, altering ecological balance.

Museum collections plus genomic techniques provide crucial historical data to assess biodiversity loss and guide conservation in fragile island ecosystems.

Original Source:

https://www.sciencedaily.com/releases/2025/09/250919085246.htm