Animal Science

Invasive aliens aren't quite the same thing as extraterrestrials, but they are still an important topic to the Convention on Biological Diversity (CBD), a United Nations initiative. Every year on May 22, the CBD celebrates International Day for Biological Diversity (IDB) "to increase understanding and awareness of biodiversity issues."

Each year focuses on a specific theme; past themes have focused on topics such as forests, food and water, climate change, and agriculture. This year's theme is invasive alien species, a threat to biodiversity, ecological, and economic well-being of our society and planet.

What is an Invasive Alien Species?

An alien species, or introduced species, is one that has been moved to a non-native geographic area by human activity. The species can damage its new ecosystem, negatively affect agriculture, or impact the health of animals and people. Wikipedia lists introduced species (plant and animal) around the world. You might find some to be surprising – Mustangs brought from Europe to the U.S., rabbits brought from Europe to Asia, red foxes brought from Europe to Australia, etc.

While some introductions of alien species are intended, others are accidental. Why does it matter, and why would someone knowingly introduce a new species?

• Intentional Introduction – Economic gain (such as a food source) is a big reason. Species may be captive or released into the wild – sometimes animals release themselves into the wild if they escape! Since people love pets, human enjoyment is another reason for introduction of a new species. Human enjoyment is also the "rationale" behind introducing non-native species of plants for decorations.
• Accidental Introduction – How can a species "accidentally" move into a new territory? It's fairly easy – three rat species spread throughout the world when travel by ship was common. Marine life can also spread by ship; for example, Zebra mussels cling to hulls and affect fisheries and electric power generation.

According to the CBD, invasive alien species have affected the native biodiversity in just about every type of ecosystem earth has to offer. The CBD's site also says that "Since the 17^th century, invasive alien species have contributed to nearly 40% of all animal extinctions for which the cause is known."

Solving the Problem

The following are suggestions from the CBD for dealing with the invasive alien species problem:

1. Halt the Establishment - Government custom checks, shipment inspections, and quarantine regulations can limit entry.
2. Economic Tools & Incentives – Educate public and raise awareness so people can make informed decisions and help limit introductions and spread.

What do you think about invasive alien species? Some are obviously more dangerous to the environment than others, but perspective plays a role as well. At first glance a rabbit doesn't look very "invasive", but if it was introduced into an area with few natural predators and you consider the rate at which rabbits multiply, you might reconsider. Same goes for wild horses – horses aren't dangerous, but they do tear up the ground and consume resources meant for livestock in some areas.

Resources:

http://www.cbd.int/cepa/background.shtml

http://www.cbd.int/idb/

http://www.cbd.int/idb/2009/

http://en.wikipedia.org/wiki/Alien_species

http://www.cbd.int/idb/2009/about/action/