Dispersal patterns key to invasive species’ success

In 1859 an Australian farmer named Thomas Austin released 24 grey rabbits from Europe into the wild because it “could do little harm and might provide a touch of home, in addition to a spot of hunting.”

By the end of the century, the rabbits had begun to overrun native ecosystems, reaching nationwide numbers of 600 million by 1950. They were propagating under a principle known as the Allee effect – the observation that larger groups of animals do better at establishing populations in a new environment. Had Austin instead spread the rabbits into many smaller groups across the landscape, things might have turned out differently.




“From the perspective of an invasive species, it appears to be a good idea to spread out to many different habitats simultaneously,” said Lingchong You, associate professor of biomedical engineering at Duke. “If they all survive, the overall growth is much more efficient. But there’s a catch because of the Allee effect; there is also a greater chance each population will fall below the critical threshold and every location will fail.”

“This can offer insights for people managing invasive species,” continued You. “If you limit the number of targets that an invasive species can travel into, you might inadvertently help them thrive.”




The results also have important medical implications, according to You.

“People need to use caution when using antibiotics,” said You. “Our bodies’ natural microbes are in some ways the first line of defense against invaders, which can often stop an infection from gaining a foothold. But if we recklessly apply antibiotics, we may destroy these defenses and make it easier for just a few foreign bacteria to spread and grow. We may remove their Allee effect.” Source : ken.kingery@duke.edu

Source: BiologyNews – Biology