A new study reported in Nature Communications has highlighted the dramatic influences that humans can have on ecology. This study has revealed that ants that have been transported out of their native habitats by humans have altered communities of ants around the world. It took millions of years for evolution to establish patterns that are being erased within a few hundred years, according to the study.
The study focused on ant insects, which compose an estimated 70 percent of the animal biomass on Earth, said first study author Lucie Aulus-Giacosa, a post-doctoral researcher at the University of Lausanne (UNIL).
The investgators analyzed the distributions of 309 non-native species, which can move around the world, mostly by accident, as commodities and tourists travel the globe. This work showed that there have been significant changes in how non-native ant species are distributed, with disproportionate impacts on ant communities in the tropics. These ants can profoundly alter the regions where they end up by changing orders and completely redrawing the ant distribution map.
It's thought that all of the areas south of the Tropic of Cancer can now be described as a single region that contains similar ant species.
"Simply put, whether you're exploring the landscapes of Australia, Africa, or South America, encountering the same ant species is now highly probable," explained senior study author Cleo Bertelsmeier, an associate professor at UNIL.
The incredible diversity of fauna, or plant life, is probably supporting this phenomenon, suggested the researchers. Ant species within this region are probably also more likely to move to new tropical areas that are similar, and readily establish new homes there.
"It's deeply disconcerting to acknowledge that within a mere 200 years of human influence, we've managed to completely overhaul patterns shaped by 120 million years of ant evolution," noted Bertelsmeier.
There has been a significant increase in the similarity of ants, which are becoming more homogenous; the trend reflects of loss of biodiversity. There is also a significant risk that some species, particularly those in the tropics, will be lost to extinction.
Now the researchers want to know more about how human trade and movement are impacting islands, which can hold particularly sensitive and unique ecosystems, and may also be at greater risk.
"Given their geography, they attract more tourists, and they import more foodstuffs. But these often arrive accompanied by undesirable guests that are potentially harmful to the local fauna and flora, which are particularly fragile. For example, we would like to understand whether this phenomenon explains why homogenization is more marked on certain islands," added Aulus-Giacosa.
Sources: University of Lausanne, Nature Communications
