I will declare my interest at the outset which is that I don’t like the domestic cat being branded an invasive species. That’s because humans brand the domestic cat as an invasive species but it is humans who made the domestic cat an invasive species. And humans are the world’s top invasive species, aren’t they? They are bloody well everywhere and they take other species with them making those species invasive species as well.
I don’t think that’s a viable situation. It’s hypocritical. It’s passing the buck. Humans love to pass the buck onto ‘alien’ species when it comes to damage to native species. And when does an invasive species no longer become an invasive species? After 10,000 years which is the duration of cat domestication? Arguably the concept of invasive species should be dropped as the world is one homogenized place in the 21st century.
Having got that out of the way, there is a website which lists the 100 world’s worst invasive alien species. They have their own criteria for listing the hundred worst invasive species. It’s a website which other websites link to and therefore it seems to have some credibility and authority.
Ironically, in fact hugely ironically, an Australian tree is considered the world’s worst invasive species. The tree is the Australian Acacia. It’s ironic because the Australian authorities are the body that complains the most about the domestic cat being an invasive species on their continent. And through human carelessness the domestic cat spawns the feral cat which the Aussie’s hate and kill in vast numbers.
Here is the full list up to the domestic cat at number 38. Yes, the domestic cat is the 38th world’s worst invasive alien species. If you listen to the Australians, you would certainly come to the conclusion that the domestic cat is the world’s worst alien species! I don’t like the use of the word alien either.
- Australian acacia
- Giant African land snail
- Calcutta myna
- Asian tiger mosquito
- Common malaria mosquito
- Yellow crazy ant
- Asian longhorned beetle
- Crayfish plague
- Shoebutton ardisia (a tree)
- Bamboo reed
- Japanese sea star
- Banana bunchy top disease
- Chytrid frog fungi
- Cotton whitefly
- Brown cat snake
- Bullfrog (Cane toad)
- Goat
- European green crab
- Seaweed
- Trumpet tree
- Fishhook water flea
- European red deer
- Triffid weed
- Cyprus aphid
- Arbre à quinine
- Freshwater catfish
- Clidemia
- Formosa termite
- Chestnut blight
- Carp
- Wondering muscle (zebra mussel)
- Floating water hyacinth
- Caribbean tree frog
- Chinese freshwater edible crab
- Cannibal snail
- Leafy spurge
- Donkey rhubarb
- Domestic cat
Link to the website listing the top 100 world’s worst invasive species: GISD
Some more:
An invasive species is an organism that is not indigenous, or native, to a particular area. These species can cause significant economic and environmental harm to the new area. To be considered invasive, a species must meet certain criteria:
- Adaptability: It must easily adapt to the new environment.
- Rapid Reproduction: It reproduces quickly.
- Harm: It causes damage to property, the economy, or native plants and animals in the region.
Invasive species can arrive in new areas accidentally or intentionally. For instance:
- Accidental Introductions: Zebra mussels (number 31 above), originally from the Black Sea and the Caspian Sea, arrived in the Great Lakes of North America by attaching themselves to large ships. Their rapid spread has threatened native species.
- Intentional Introductions: Some species are intentionally introduced for pest control or as pets. However, these introductions can lead to unintended consequences. For example, cats brought to Marion Island for mouse control multiplied rapidly and endangered local bird populations.
- Ecological Impact: Invasive species often outcompete native species for resources, affecting ecosystems. Burmese pythons released into Florida’s Everglades, originally from southeast Asia, prey on local species, including wading birds.
In summary, invasive species disrupt ecosystems and can have far-reaching consequences for both the environment and human activities.
