'Invasives like it hot'
2007-08-08 09:29
Cape Town - Global warming gives invasive species the edge over their indigenous counterparts, a study by South African and Norwegian scientists has found.
The finding is based on a study of springtails, tiny insect-like creatures that live in soil, on the Southern Ocean's Marion Island.
It is to be published in the Proceedings of the Royal Society on Wednesday.
"In essence, invasives like it hot, whilst indigenous species like it cold," said lead author Prof Steven Chown, director of the DST-NRF Centre of Excellence for Invasion Biology at Stellenbosch University.
He said the island was home to 16 springtail species, five of which were invaders thought to have been introduced following the establishment of the South African scientific station on the island in 1947.
In an experiment mimicking climate change, the researchers found that invader springtails were better able to modify their behaviour, morphology or physiology in response to a changed environment.
This meant warmer conditions promoted invader survival and reduced it significantly among indigenous springtails.
Chown said Marion had a cool, wet, windy climate that had changed substantially over the past 50 years, including a one degree Celsius increase in mean annual temperature and a decline in precipitation of more than 500mm a year.
"This differential physiological response provides support for the idea that in temperate terrestrial systems experiencing global change-type drought, invasive species may well be at an advantage relative to their indigenous counterparts," Chown said.
- SAPA