When people bring new species into a habitat, they can threaten local plants and animals.
The new plants and animals can also cause big changes in their new habitat.
Plant-eaters take the food of local animals, while new hunters kill local wildlife.
People brought mongooses to hunt rats, but they became pests.
People have brought new animal hunters to many areas. Mongooses were introduced to Puerto Rico to hunt rats. But they soon threatened local snakes and spread the disease rabies to other animals on the island.
Rabbits brought to Australia nibble pastures bare.
New wildlife brought to Australia caused great changes there. Some of the newcomers took over from local species.
European settlers released rabbits in Australia. The new arrivals bred quickly and became pests, stripping grasslands bare. This left nothing for local species. Rabbits are now killed as pests.
Water hyacinth is now a pest on many waterways.
New plants as well as animals can become pests when they thrive in their new homes.
In the 19th century, a pretty plant called the water hyacinth from South America was released in lakes and ponds in North America, Africa and Asia. It spread quickly and now completely chokes waterways in many areas.
Hedgehogs brought to the Hebrides steal birds’ eggs.
Animals of remote islands are particularly threatened by new predators because they are often not used to being hunted.
On the lonely Hebrides Islands in Scotland, local seabirds are threatened by hedgehogs. These were brought to the islands to eat snails and slugs in people’s gardens, but they now prey on birds’ eggs.
Scientists are trying to reduce the numbers of hedgehogs on the islands. But there is a lot of disagreement between the bird lovers and the hedgehog lovers.
Picture Credit : Google