A new study has put to the test what happens when dominant ant species vanish from the ecosystem – with worrying results.
The joint study, led by a team from the University of Western Australia, Australia's national science agency CSIRO and James Cook University, found the loss of dominant ant species was quickly compensated by rarer species, with other similar native ant species effectively picking up the slack by taking on the additional roles left behind by the original species.
"Insects are everywhere and some people question what all these species do in ecosystems," study lead author and JCU entomologist Dr Peter Yeeles said.
"Here, the research is showing that they provide a built-in redundancy that allows ecosystems to absorb shocks.
"Think of them like pieces of scaffolding. Remove one, or a few, and the structure still stands because each part offers a degree of redundancy to the other parts. Redundancy makes systems resilient. Without it, even small disturbances can cause big collapses."
But Dr Yeeles said the study also found that there is likely to be a limit to how much the ant community can compensate for species losses.
"Losing the common species can be like replacing a few reliable generalists with a team of specialists," he said.
"You might maintain performance, but you also increase the risk if one of them goes missing.
"With so much reliance on specific roles, losing any more species could cause much greater ecosystem damage than before."
Dr Yeeles said the study highlighted how important dominant ant species were in performing everyday tasks that keep ecosystems "running smoothly".
"It is easy to forget how important ants are in the majority of terrestrial ecosystems. They're often referred to as ecosystem engineers because they have such profound effects on the ecosystems they live in," he said.
"Some ant species are granivores, meaning they eat seeds, so they regulate plant communities.
"For example, in an agricultural setting ants consume weed seeds, providing free weed control services. They're also important for soil structure as they dig and increase soil porosity to allow water infiltration. The list goes on."
Dr Yeeles said managing insecticide use and land conservation were just some of the measures that would need to be taken in preserving diverse native ant communities so they maintain their built-in buffering capacity against unexpected losses.
"Globally, scientists are increasingly concerned about dramatic declines in insect populations, including many once-common species," Dr Yeeles said.
"We must act now to protect not only rare species, but also the everyday insects that quietly keep our world running."
The study was published in the journal, Nature Ecology and Evolution.
