Zoo has got 2 new additions. In fact they came as totally unexpected intrusions of 2 unwelcome visitors. ZooLander reports:“Two Aliens seized at the airport have been sent to the zoo” was a message some media reported last week. The word alien would conjure thoughts of the famous TV series X-files and spur curiosity among many. But this pair of aliens doesn’t have big eyes, slim bodies or long fingered hands as shown in the famous Alien Films. These aliens are just like our mongoose -- with flat bodies -- and continously sniffing their new environs through their small fences. These are Ferrets - a species of animals that can breed easily if released to the wild, and have the potential to be a serious threat to other animals.
A Sri Lankan returning from Dubai had brought these animals with his cargo. The customs had detected the unwelcome visitors and called its Biodiversity Protection Unit (BPU). The BPU officers identified the animals and identified them among those which could be a potential threat. So they had to end up their miles long journey from Dubai in the Dehiwala zoo.
Ferrets in fact belong to the family Mustelidae to which similar creatures called Weasels belongs. They are a carnovora which hunts other small mammals and birds. The Ferret known scientifically as Mustela furo is the domesticated form of the European pole-cat (Mustela putorius). Ferrets were domesticaled as far back as 2500 years in Europe, mainly as hunting assistants, according to literature. They were exellent at hunting small rodents and rabbits. Since the 1970s, Ferrets began gaining in popularity as pets in the USA and around the world, and some were released to the wild. Either that or those who were introduced intentionally to control rodent populations started causing problems in some parts of the world.
Ferrets are particularly deadly to ground-nesting and flightless birds. Ferrets were introduced to New Zealand from Europe in the 1880s, along with stoats and weasels, to control rabbits that were breeding out of control. By 1900, ferrets were well established in the wild, and definitely played a role in the decline of native birds such as the kiwi, weka and blue duck, and the extinction of kakapo in mainland New Zealand. Kakapo are now only found on mustelid-free islands. Ferrets also affected the Sea Bird population in Irish islands. Ferrets ability to adapt to tougher environments and ability to breed quickly make them perfect Invasive Alien Species.
What are Invasive Alien Species?
Invasive alien species (IAS) are species whose introduction or spread outside their natural past or present distribution, threatens biological diversity. The Convention of Biological Diversity (CBD) - the United Nation’s arm working on protecting earth’s valuable biodiversity -- mentions these Invasive Alien Species as occuring in all taxonomic groups, including animals, plants, fungi and microorganisms, and can affect all types of ecosystems. While a small percentage of organisms transported to new environments become invasive, the negative impacts can be extensive and over time, these additions become increasingly threatning. A species introduction is usually caused by human transportation and trade. If a species’ new habitat is similar enough to its native range, it may survive and reproduce. However, it must first survive at low densities, when it may be difficult to find mates to reproduce. For a species to become invasive, it must successfully out-compete native animals, spread through its new environment, increase in population density and harm ecosystems in its introduced range. To summarize, for an alien species to become invasive, it must arrive, survive and thrive.
Other Aliens in Sri Lanka
The International Union of Conservation of Nature (IUCN) lists 105 Alien Species that has become invasive in Sri Lanka. These aliens range from tiny alga, molluscs, insects to mammals, fish and lots of trees and shrubs. Invasive Fish species has caused the most notable damage to the native species where some of them almost wiped out the native fish in some waterways. Thilapia - a famous fish in freshwater aquaculture, that has been introduced to man-made tanks, has made sure it eats out the egg and younger fish of other natives to become the dominant after few decades of its introduction. Rainbow Trout that has been introduced to the streams in the hill country by the colonial British for sports fishing also causing similar damage. You’ll also be sometimes affected by a land snail that causes damage to plants in your garden.That could also be due to the invasive species giant African land snail. Even though this species has not caused a devastating effect as invasive fish, the ferral pigeons that has been spread around our cities, are also considered an invasive species. Invasive plant species are already causing problems in many of Sri Lanka’s national parks. Bundala National park is affected by Cactus and a shrub called Kalapu Andara while nearby Udawalawe National park is threatened by Lanthana, commonly known as gandapana. A thorny exotic plant called Gorse (Ulex europaeus) has spread in Horton Plains together with another fern. Knuckles too has acquired a new species and the forest department recently conducted a program to eradicate it.
published on LakbimaNews on 04.07.2010
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