Thursday, 1 October 2009

Tokelau Ant Communities

Tokelau is a small place, far away from anywhere. Unfortunately, like all Pacific Islands, it has been overrun by invasive ants, which have massive impacts on the ecosystem of the islands. Phil Lester and his crew from Victoria University in Wellington, New Zealand made the most of a bad thing and took the opportunity to investigate community structure and assembly processes on these islands. What they did which few others have done was investigate the effect of abundance on community assembly, as opposed to just recording which species are found in the same places as each other. As expected, they found that as the abundance of ants went up, the number of species present decreased.

The ant that was dominant, was the yellow crazy ant, Anoplolepis gracilipes. And boy, was it dominant! Maximum abundances were 100 times that of the most abundant species. Rather unsurprisingly, the authors comment that
"in high abundance, A. gracilipes was associated with reductions in the number of co-occurring species and their abundance."
In this research, the authors only looked at the effect on other ant, which are also introduced to Tokelau. However, the effect of the ants can be devestating. One of the most publicised crazy ant invasions is their effect on the ecosystem of Christmas Island, Indian Ocean, home to the charismatic red land crab. A couple of reports about the invasion in the popular press are this one from the ABC and a report from the Australian Government

PJ Lester, KL Abbott M Sarty and KC Burns. 2009. Competitive assembly of South Pacific invasive ant communities. BMC Ecology 9:3

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