Ecosystems under threat: Invasion of the alien species

[FernBell]

One of the greatest threats to the world's biodiversity - the richness of its wildlife - is the spread of alien species that have been deliberately or unwittingly introduced into new habitats where they can thrive.

In many ways, the movements of plants and animals around the world by human activity has been an inevitable consequence of the globalised economy in which we now live. Without such movement, we would not enjoy many of the benefits of modern life - but the consequences have been severe for fragile ecosystems.

What makes an alien species able to invade and then damage the biodiversity of its new home ultimately comes down to its ability to outperform resident lifeforms. Alien animals and plants become invasive and damaging because they can grow faster, breed more profusely, disperse more widely, tolerate a wider range of conditions or simply grow bigger than the resident species of the invaded ecosystem.

But of course, there is another factor at work in deciding whether an introduced species becomes invasive. It is whether the animal or plant in question is able to form some sort of close association with man - arguably the most destructive invasive species on earth. After all, the oldest invasive species are the animals and plants that have been either domesticated by humans for many centuries, or, in the case of the mouse and rat, have lived in close proximity to man.



http://news.independent.co.uk/environment/article1962989.ece

[Hestia]

1. An excellent book about this topic is

"Collapse" by Jared Diamond, which is a continuation of "Guns, Germs, and Steel", which won the Pultizer Prize. Easter Island is the case in point for ecological devestation, due to the new islanders bring in rats on their canoes/dugouts. Rats desimated the nesting sites of birds, to the point that rats were the only mammals that Easter Islanders had to eat. Also, as the islanders chopped down every tree on the island, the rats would eat the nuts to get new trees from germinating. More to this story obviously. Great read.

[dipsydoodle]

2. Japanese knotweed is a prize example

The Victorians introduced it to the UK. Invasive is an understatement.

It is only one of two terrestrial plants dealt with by the current version of the UK Wildlife and Countryside Act under which it is illegal to cause it to grow in the wild.
http://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm

Funny thing is you can actually eat it used as a substitute for rhubarb with a crumble !

[Botany]

3. thanx for the post

bush honeysuckle, garlic mustard, purple leaf winter creeper, and multiflora rose
are the big problems around me (Central OH).

[Boomer]

4. One word

kudzu

[ramapo]

5. Out of Eden - also highly recommended

This too is an excellent book on the problem.

You'll learn that invasive species are so widespread, and so well established, that there is no going back. I was surprised to learn that even the lovable earthworm is an invasive here in the Northeast and that they've actually had a detrimental affect on our forests.