One of the things we discussed at my course on the Water of Leith earlier this week (see this post) was introduced species and the effect they can have on the ecology of an area.
We looked at some of the UK's invasive species. These include Giant Hogweed introduced as a garden ornamental but which since escaped and grows on rough ground and has a corrosive sap that can cause injury. American Mink has been a problem since it was released from fur farms by animal activists. It eats the chicks of water birds and competes with otters.
Not all introduced species are problematic. Trees such as the sycamore and horse chestnut were introduced into the UK a long time ago but have become naturalised and are part of our ecology.
So we come to rabbits. Many readers of this blog think of rabbits as the ideal pet and so they are! But they are also a wild animal. They were introduced into the UK by the Romans and again by the Normans as a food source. They then escaped and bred very successfully. They are a well known part of our countryside and an excellent food source for many predators.
Rabbits were introduced in 1859 to Australia where their only natural predators were being hunted to extinction, so there was no check on their numbers. In ten years the population increased to many millions. Myxomatosis was introduced in 1950 and numbers dropped from 600 million to 100 million in ten years but numbers increased again to around 250 million by 1991. Other methods of control are being used but rabbits are still a huge problem in Australia. I'm saying all this to outline the problem rather than to advocate culling animals.
So the status of an introduced species depends to a large extent on the ecology of the area it is introduced into.
18 comments:
If people are stupid, ignorant or thoughtless enough to introduce species to a place where they do not belong, then it’s too bad, and they cannot really be ‘un-introduced’ later. In the case of plants, it is often futile to try and remove them (though I wish you all luck at the Water of Leith with the Himalayan balsam), and in the case of animals, it’s both futile and cruel. It’s a bit like wanting to un-invent nuclear weapons, or to un-invent urban motorways.
But then I’m bound to say that, being a full-time bunny-hugger!
It's heart-breaking that there are places where they have to cull the rabbit population for the sake of the rest of the ecosystem. We humans have a nasty habit of meddling, then thinking the solution is to meddle some more. And some more. Too clever for our own good, and for the good of other species.
I vote for pets!!! Joking. Except, if you release a domestic rabbit to set her "free", then definitely prey. And that's why we don't have a problem with the introduced European species of rabbit in the US.
I've read a lot about the rabbit "problem" in Australia and New Zealand. It's not just rabbits over there, there are several introduced and very invasive species, that just aren't coming to mind.
I really have no opinion on culling. I think no matter how you slice it, the whole situation just sucks.
Perhaps the most invasive species of all is the human.
I agree with all the other comments and having grown up in Australia I have seen the attitude to 'non-native' species by the (introduced European) locals to the camels, rabbits, cane toads, foxes, water buffalos ... the list goes on.
Perhaps the answer is to make a place for all beings to live side by side because if people are yearning to live the way 'it was' 200 or 400 years ago then they would not have destroyed and populated so much land as they have done.
Wow, with so many species of bunny native here in America (3 kinds in the northeast alone), it's strange to learn of a place where they are not native. I'm definitely against introduced species, but like Howard says, it's cruel and futile to try to cull them after the rabbit's out of the bag, so to speak. It's too bad the buns are hurting native species there. I've never heard of bunnies here attacking birds. Ours are strictly vegetarian!
We have hydrilla choking the Potomac River, and we introduced kudzu in the south which was to inexpensively feed cattle but is not liked by them and quickly grows up over everything--trees, power lines, houses.
Unfortunately, all of the above. Unfortunately, much of the time when they turn out to be pests, humans have manipulated the environment in some way, thinking to make it better, but only creating havoc and then blaming the problem on the organism they introduced.
Humans are just great at messing with the natural order. Here in the US folks need to remember that people regularly turn pet rabbits loose. They begin to breed and quickly become a huge problem.
In Florida people have been releasing their pet Boas and Pythons. They are really screwing with the natural order. When a Park Ranger saw a large Boa eating a small aligator they declared it legal to kill the exotic snakes. There was also a large Anaconda found here in a pond. Some people need to have their heads knocked together.
Howard, I agree, they can't be un-introduced, but humans caused the problem and need to do something.
Bunnygirl - yes we meddle way too much
Lisa - yes lots of introduced animals are problems in Australia and New Zealand, I was just using the rabbit as an example
Annette - humans are definitely the most invasive species. And no we can't go back, if only we hadn't been so arrogant in the first place
dguzman - the main problem with rabbits in Australia is that they eat the native plants, they just eat who areas bare which kills the plants and causes huge soil erosion problems.
Glenna - I've heard about the kudzu problem, that sounds a bad one
bunnits - exactly
Christina - people set pet rabbits free here too, though that isn't a problem except for the bunnies usually. Other pet species are released too and can cause real problems
I know in my head that rabbit invasion can be bad for farmers etc.. but in my heart I just love seeing the little bunnies jumping around the fields, flicking their little white tails as they run away from us. It makes my day to see the cute little wild rabbits around our village when I go out for walks.
It's all sort of case by case, I suppose. I know I can't save every rabbit in the world and in fact that would cause a huge problem. I do know I can spoil a few rabbits. All things being equal if we asked an impartial passerby from another planet what species on earth seemed to have the most problem fitting in to the hierarchy of nature the answer would be: humans....
I think that introducing alien species of plants and animals is a risky business, and people who do it irresponsibly, do a lot of harm.
Since we can't all be experts on habitats and natural balance, we should probably leave off on smuggling plants and perceived pets across continents!
Here in Maine we have an invasive water plant that travels in on boats and takes over whole lakes, leaving little oxygen for the fish and other species. Now that it's been introduced, it's a constant battle to protect or reclaim some of the beautiful lakes in this region.
What a bunch of comments! Similar issues in many places - same here - some introduced accidently, some with good intentions, some with no forethought. Keeps quite a few folks busy eradicating!
There are a couple of communities near me (Victoria, B.C. a notable one) that have a large wild rabbit population.
They are talking about a culling program because of reported health issues. In Victoria they even contemplated administration of birth control drugs to the wild population by leaving the drugs in bait...meaning both males and female rabbits would be eating the same drugged bait, not to mention any other animal that happened upon the food. How ill-advised. A disaster in the making.
It's a complicated problem, one best solved without chemicals IMO!
JoMo - I agree, best to avoid bait as it can be so indiscriminate
the human - yes I love to watch rabbits, even though i know they are a pest, but at least here they're a mangeable pest with predators, unlike in Australia
D Moll - indeed we are the most troublesome
Lynda - yes I agree
Rabbits Guy - thanks
Interesting you mentioned sycamore trees. Although they have become widespread, there are still very few minibeasts that live in them. Maybe thay haven't become as much a part of the ecosystem as it appears?
I have read all the other comments with great interest. It really is a worldwide problem. I do agree that once it is done it cannot be undone. It happens everytime humans interfere with the natural order of things. Another obvious one being the introduction to Britain of the grey squirrel which then went on to take over from the native red squirrel. The damage they do to young trees is immense. What an immense and emotive problem it is.
Great post! You can't keep rabbits in Queensland, Australia where I live because they are such a pest - though you can over the border which is a bit stupid. The toad is one of the worst pests in Australia - but very hard to eradicate.
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