Plant and Animal Invaders

Plant and Animal Invaders
by Krista Bergesen

The year 2010 marked the beginning of the UN’s International Year of Biodiversity in response to the present planet’s extinction crisis. But after a while, a person could start to wonder: what are some of the driving forces behind the loss of biodiversity on the planet? Well, there’s fossil fuel burning and deforestation to name a couple. That isn’t the end of the story, however.

Humans may have messed around with the ecological system even more than you may think. The increase in travel and importation going along with a global economy has allowed the transportation of many non-native plants and animals to sensitive habitats.

And that is just the beginning. These invasive species consume the resources of the original flora and fauna in the system. According to the International Union for Conservation of Nature, 40% of species are recorded as extinct because the effects of invasive species.

This has even caused economic damage. Yearly, 1.4 trillion dollars are spent worldwide on control measures and habitat restoration because of the havoc wreaked on the environment. The US itself suffers a loss of 138 billion dollars a year just for its own issues with invasive species.

As already stated, the unattended and unmanaged environment containing invasive species can result in extinction of native species. What’s worse is that the changing global temperatures are enabling non native species to gain a stronger foothold in their new environments.

For example, British Columbian forests are being plagued by mountain pine beetles, whose population has invaded and subsequently increased in number due to the milder winter temperatures. Normally, these creatures would not survive in such a harsh climate, but with the increasing global temperatures they can move further north with increasing speed in destructive numbers. Predictions have estimated that this beetle will be responsible for the devastation of 80% of pine in the province by the year of 2015.

Eradication and control efforts are commonly made against invasive species. However, in areas with multiple introduced species, it can become very difficult to foresee the consequences of various control efforts. Eradicating one invasive species may actually lead to increased damage from another.

The New Zealand ecosystem, only recently populated by humans, has faced many difficulties because of human-introduced species. Their many “management responses” dealing with the threats of invasive plants and animals have often had unforeseen consequences. Livestock, brought by human colonists has limited the habitat of Whitaker’s skink. However, when livestock was removed from certain areas to restore skink populations, predators moved in only to further reduce the skink numbers.

Despite difficulties faced in ecological restorative efforts, they are exceedingly important in maintaining diversity. To be successful, the control projects must be “intensive” and continued for long periods of time, otherwise any progress made with restoration will be lost. Also, when considering a project, all possible outcomes must be considered to ensure that more negative effects on the system are not accidently created.

It should be noted that many successful control efforts in have been documented, and that native species is preservation can be achieved. As global temperatures rise, these efforts will be more and more essential to preserving biodiversity and help slow the accelerating rates of extinction worldwide.

Berger, Matthew. “Invasive Species Threaten US Biodiversity” Guardian Environment Network. <http://www.guardian.co.uk/environment/2010/jan/05/invasive-species-us-waterways>
5 Jan 2010.

Strong, Donald and Robert Pemberton. “Biological Control of Invading Species–Risk and Reform.” Science Magazine. Vol. 288: 1969-1970. 16 Jun 2000.

Norton, David. “Species Invasions and the Limits to Restoration: Learning from the New Zealand Experience.” Science Magazine. Vol. 325: 569-571. 31 Jul 2009.

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Filed under Biology, Ecology, Genetics, Policy

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