The issue of invasive species is a problem world wide. Creatures are brought from their native habitats intentionally or by accident and the results can be anything from beneficial to disastrous.
Recently we have written about invasive hippos in Colombia, domestic cats (gone feral) in Australia, and spiders in the United States. Of the three highlighted, the Joro spider so far is the least damaging. Australia estimates that there are six million feal house cats in the country and they are devastating unique wildlife. Cats are superb hunters and flightless birds and small animals are no match for them and are being driven to extinction. The hippos in Colombia, like Burmese pythons in Florida, are also disrupting local wildlife and may drive some creatures to extinction. Once established. invasive creatures can be very hard to control.
In Alaska the problem is a small opportunistic mammal that almost every one hates: rats.
Rats are one of the most damaging invasive species in the world and are difficult to control because they are commensal. The word comes from Latin and refers to sharing the same table, which is what rats do. They live very close to humans and depend on human negligence and waste for their existence. They are legendary disease bearers and they destroy far more food than they eat. The rats in Alaska came with sailors from other countries and have a toehold in the state. The weather is a big help in trying to keep them at bay because the extreme temperatures are too much for them. There are native rodents, including muskrats, but they are adapted to the climate unlike the invaders.
Alaskan authorities are recommending the same control measures recommended everywhere: deny them food and shelter. If you watch your crumbs, keep an eye on your pet’s food and contain your garbage they will have little to eat. If you clean your house, and seal cracks and entrances they will have nowhere to live. Outdoors, cold weather and abundant predators will soon eliminate them.
Meanwhile, Anchorage appears to be rat free and hopes to stay that way. Scientists can point to one great success story: Hawadax Island. The small island in the Aleutian Chain was colonized by rats after a shipwreck. Rats proliferated and took over the island as they were the top predator in the locale. in 2008 a consortium of federal, state and conservation groups set out to eliminate them.
They used poison, which worked well but had some collateral damage. The island has been rat free for ten years and the benefits to the island appear to outweigh the collateral damage which probably included a few eagles as well as other animals that ate the poison. Birds have rebounded because the rats aren’t there to eat their eggs. Kelp appears to have rebounded too. The birds are back and their lifeways contribute to growth of kelp. Scientists say a rat free island is noisy with birds, an island with rats is silent because there are few birds.