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100 of the World's Worst Invasive Alien Species
Ant writes "100 of the World's Worst Invasive Alien Species list says: 'Invasive species have been recognised globally as a major threat to biodiversity (the collected wealth of the world's species of plants, animals and other organisms) as well as to agriculture and other human interests. It is very difficult to choose 100 invasive species, from around the world, that really are "worse" than any others. Species and their interactions with ecosystems are very complex. Some species may have invaded only a restricted region, but have a huge probability of expanding, and causing further great damage (e.g. see Boiga irregularis: the brown tree snake). Other species may already be globally widespread, and causing cumulative but less visible damage. Many biological families or genera contain large numbers of invasive species, often with similar impacts; in these cases one representative species was chosen. The one hundred species aim to collectively illustrate the range of impacts caused by biological invasion.'"
For places where cats are not normal, like Australia and other islands, cats have caused a huge amount of damage to the native fauna. Cats are wiping out small animals and birds, either through predation or through competition.
One Man's Trash Is Another Man's Treasure.
Nah, homosapiens should have been #43... The list is alphabetical.
There are probably two ways of judging how bad an invasive species is: the negative effects on other "native" species and ecology, and how hard it is to eradicate. As an example lets look at the salt cedar , which is bad on both of these counts.
This plant is a huge success of natural selection. It can survive in all sorts of environments, and scales wonderfully eeking a survival in the middle of the desert as a shrub or thrive in wet forest as a tree, but always leeching every and all the resources available to it. It has an extensive root system which soaks up all the water available, which not only chokes off local trees, but prevents ground water from replenishing streams and aquifers, hurting the ecology of the entire region. It is near worthless as a source of food for animals, unlike the plants which it displaces.
Getting rid of it is not quite as easy as using a chainsaw. As I mentioned, it has an extensive root system which survives and resprouts after the above-ground portion of the plant has been cut down. The salt ceder also salinates the soil, making harder for other plants to regrow if the infestation has been there a long time before removal. Most places resort to pesticide to get rid of it, either by spraying areas that are completely infested, or by poisoning the trunks of individual trees that have been cut down. Also, "just chainsawing it", is not as easy as it sounds. It is an extremely time consuming task. Likewise, pesticides are not something that you want to go overboard with. In general these trees have been spreading over decades and we are just now getting around to dealing with them, so you don't want to just rip out all the salt cedars as fast as possible without a plan for reintroducing native plants.
Here in New Mexico, the salt cedar is concidered to be one of the greatest threats to our water supply, and a great deal of effort is being made to eradicate it, and progress is being made, but it is necisarrily slow.
For all those who complain that #1 is a tree, the list appears to be alphabetically ordered.
Where law ends, tyranny begins -- William Pitt