The cryptic impacts of invasion: functional homogenization of tropical ant communities by invasive fire ants

New research led by Mark Wong is the first of its kind to rigorously investigate the impacts of Red Imported Fire Ant on ant communities in Asia. The Red Imported Fire Ant ('fire ant') is a species native to South America which has spread globally, and is listed among the world's worst invasive alien species.

Research has shown that fire ants seriously impact ecosystems in North America (where they were introduced around the 1930s), and more recently in Australia and Asia where they have since been introduced. However to date there has been comparatively little research on their ecological impacts in these two continents.

New research, published in Oikos, has focused on populations of fire ants in Hong Kong. Lead researcher Wong says: “Ant diversity is important for optimizing a wide variety of ecological functions such as the control of insect populations, the transport of nutrients into the soil, and the dispersal of seeds. By studying invaded landscapes in Hong Kong, we found that the fire ants led to a loss of diversity in ecological function or ‘functional diversity’ in local ant communities.”

To discover this, Wong and colleagues compared uninvaded and invaded ant communities in terms of their ecological attributes – such as the sizes and shapes of the ants’ bodies, eyes, jaws and legs – which are used for performing different ecological functions. This allowed them to assess the potential for different communities to deliver a variety of ecological functions.

Another key finding in the research was that changes to the functional diversity of the ant communities were not detected by commonly-used measures of biodiversity, such as species richness.

“To me, this highlights the value of adopting a holistic approach to understanding and conserving biodiversity. Counting species may be an efficient way to summarize biodiversity, but accounting for how the ecological properties of different species relate to wider ecosystems provides us with a far better picture of how nature is put together, and how it may respond to change.” says Wong.

Increasing numbers of plants and animals are moving across borders due to global human activity, and Wong’s next research investigates how species’ ecological attributes (or 'traits') can be used to improve predictions about the impacts of biological invasions on native species. Wong also recently led a review discussing how the use of traits can advance the understanding of community and ecosystem ecology in insects.

 

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Cover photograph of Red Imported Fire Ant by Francois Brassard.

 

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