Just attended (part) of the Seminar organised by the Malaysian Nature Society, sponsored by the Economic Planning Unit here in the lecture hall across from my office.
If you have been to Australia you would have noticed the huge signs welcoming you saying "Declare it or thrash it" and right underneath the signs are huge thrash bins. You can't bring in any meat products and other fresh produce. An alien species could wipe out their whole agricultural industry. I also remember when we were traveling by car from Washington State to California and was surprised to see a checkpoint where all they wanted to know was whether you have any fresh fruits in your car. I looked around our car, saw the plastic bag of some left over cherries (grown in California, bought in Oregon), showed it to the officer, who took it and promptly dropped it into the thrash bin.
Malaysia is full of alien species. The best known are the rubber and and oil palm trees but these have economic value so we welcome them. But did you know that the British introduced crows to control insect infestation of coffee plants (another alien) in the Klang area? Now of course crows are everywhere in Malaysia - and coffee is dead. Cats are aliens and so are many types of pets. They are pretty to look at but when their value drop or people got tired of them, what do they do with the pets? Remember the Lohan fish which was the craze just a few years ago and fetched hundreds or thousands of dollars? Well, when the market for Lohan collapsed, the owners released them into the rivers. These fish are predators - they eat up all the algae and the eggs of other fishes. Now, it seems they have become the dominant species in many rivers in the Klang Valley. So, what is the problem with that? Lost of bio-diversity and this can have severe ecological and economic consequences. Mashbor calls this biological pollution. Kumar of MNS who's office is near the Botanical Garden in Penang reports very often seeing well-meaning owners releasing their pet fish and turtles in and near the Garden, severely disrupting the local ecological system. All the hycinths plants (which are also alien and invasive but have tide and erosion control uses) are now gone, eaten by the turtles.
The beautiful angsana and flame of the forest are all aliens. In fact, all the flowering plants in Malaysia are imported; even the national flower, the hibiscus (bunya raya). Yes, we want diversity but alien species can dominate and wipe out indigenous species.
What can we do about it? Nothing - once the aliens have a foothold.
USM's Main Campus in Penang Island is a Bird Sanctuary and the scientists are quite happy about the biodiversity on campus - 130 species of plants, 17 species of mammals from 9 families, 106 species of birds from 34 families, 26 species of reptiles from 11 families and 8 species of amphibia from 4 families. Pretty impressive, don't your think?
But I think the worst invasive species are OURSELVES - the humans. It gives me a heartache whenever I pass by the two lakes near Desa Harapan (see picture below).