Friday, January 26, 2007

Upsetting the balance

I just read this off the Alley Cat Allies website.

One of the remote islands off Australia decided they would get rid of the cats on the island because they were preying on the birds. It turned out to be a huge mess because then rabbits and rats started becoming an even larger threat to the birds. Now they're trying to kill off the other animals there too!

Cull upsets ecological balance

22 Comments:

Blogger budak said...

It seems removing the cats was only half the solution, as rabbits and rats are also introduced species. On island habitats, non-native mammals (even supposed benign species like rabbits) can have devastating effects on the local avifauna.

26/1/07 4:13 PM  
Blogger Dawn said...

Also it seems the situation is much worse now than when the cats were present.

26/1/07 4:17 PM  
Blogger calsifer said...

Just like what happened here in 2003. AVA scrapping SCRS, stepping up culling during SARS, NEA banning cats from eatery premises leading to increase in rats around such places. So need to spend more money on poisoning them, publicity blitz to encourage hygiene in eateries... our money.

26/1/07 4:19 PM  
Anonymous Anonymous said...

Will be ever learn **sigh**

26/1/07 4:25 PM  
Blogger Hai~Ren said...

I guess removal of introduced predatory species from islands makes the situation more complex, especially when more than 1 introduced species is involved.

I think any plan to remove apex predators like cats or dogs that threaten native species must also take into account the removal of other introduced species that serve as prey, as shown by this example.

28/1/07 8:30 PM  
Blogger Hai~Ren said...

I'm not sure what the views of others will be, especially since there might be some who are against culling even in this case. Just to bring my stand across clearly, I am for culling of cats in the case of islands where endangered species are threatened through predation.

After reading the article, I think there is one fundamental flaw:

The title presupposes that there was an 'ecological balance' in the first place, before the cats were eliminated. Of course, while the cats should have been removed sooner or later, I feel that a more comprehensive plan to deal with the other intrduced species should have been employed rather than just eliminating the cats alone. After all, no species exists in a vacuum.

While I do support the removal of introduced species, especially when delicate ecosystems and endangered species are involved, it appears that no one in this case had any plans to deal with the rabbits and rats on the island in conjunction with removal of cats.

28/1/07 8:54 PM  
Blogger Dawn said...

Sometimes perhaps the question is when is a species 'introduced' - is a species considered still new enough to remove 20 years after? 50? 100?

If one looks at it, people go onto the island and just by their presence have already messed up the ecosystem. It's too late to wantto un-do it. Paradise was spoilt the minute man landed there.

On another level, one wonders - isn't there another way they could have saved the birds without killing the other animals?

28/1/07 9:14 PM  
Anonymous Anonymous said...

A cat is a cat is a cat. Labels such as 'introduced', 'invasive' and 'feral' do not change a creature's basic ability to suffer or feel pain. For this reason, I am not willing to openly embrace the conservationist cause, neither will I favour the interests of one species over another. The cats were probably what kept the population of rabbits and rats down in the first place, and I feel that a mass poisoning campaign would only introduce more pollution into an already embattled ecosystem.

29/1/07 1:53 PM  
Blogger budak said...

I don't think anyone really likes the idea of having to forcibly remove (even to the extent of killing) cats or other non-native species from a habitat, but there are times when not doing so would mean the eventual extinction of native animals on these islands. That to me is a greater evil, surpassed only by the irresponsibility of men who introduced the non-native species in the first place.

29/1/07 2:53 PM  
Anonymous Anonymous said...

I don't believe in speciesm, therefore I must respectfully disagree. To me there is no inherent difference in an extremely rare animal and a common one. The interests of all must be taken into consideration. I realize that this is an unpopular point of view, but there is no guarantee that the local avifauna will flourish after the removal of introduced species or whether complete removal of all rats and rabbits is even possible.

29/1/07 4:31 PM  
Blogger budak said...

If you think that the interests of all should be taken into consideration, why not the interests (i.e. survival) of species which face extinction from cats (no thanks to men)? There is much more than just a point of view or desire to be popular in the concern of ecologists wanting to maintain the integrity of ecosystems by removing invasives or preventing them from being reintroduced. With animals like birds which form vital parts of food chains in both their breeding grounds as well as far off feeding areas, the impact of their loss is likely to be felt in more than just their home islands. In the case where introduced animals (be it cats, rats or rabbits) threaten native ones, why shouldn't people seek to rectify earlier mistakes?

Some info on cats as invasives can be found here: http://www.issg.org/database/species/ecology.asp?si=24&fr=1&sts=

29/1/07 5:19 PM  
Blogger Dawn said...

I wonder if alternative solutions were considered? One option for example - belling the cats and ensuring they were sterilised. I don't know (and it doesn't say) if they tried anything else before deciding to get rid of the cats.

29/1/07 5:20 PM  
Blogger Dawn said...

I think none of us want to see any animals instinct or killed unnecessarily. I think my point was what this 'necessary'?

I see that the belling option was mentioned.I've seen those different studies (and vastly different results) on belling.

One thing I thought was interesting in the piece Budak sent was this "However, unambiguous evidence of cats causing a decline in a prey species is difficult to find as other factors, such as other predator species, may also be involved in the decline (Dickman 1996)." It makes me wonder why if protecting the species was the main aim, why often cats are the only ones that are removed (as in this case). Is it because it seems the easiest option? It certainly would be harder to get rid of the rats and the rabbits. It sounds as if someone didn't do their homework- and if they didn't consider something else like the rats and the rabbits, I wonder what else they forgot to factor in.

In general, cats have been found to kill rats as well as their main prey. Something else the people who arranged the killing may have forgotten to consider.

29/1/07 5:41 PM  
Blogger calsifer said...

I am of the view that if it comes down to it, we have to accept that culling "introduced" species to save endangered native species is better than the alternative of the former competing or eating the latter off the face of the earth.

But like Dawn, I feel this is acceptable only after all other options are exhausted.

The way the cats are being handled isn't right. The way they're handling the aftermath is worse. Poison? Pfft.

The reach of Man's greasy fingers know no bounds. It's not only the obvious issues that are pepetuated by us. EG Puffins are declining because the small fishes that they depend on to live and feed their young are being overfished to hell. RG sand eels, smallest of fish: "Industrial fisheries pursue these important fish species - which make up the bottom of the food chain - not for human consumption, but to provide fish meal and oil for rearing livestock and farmed fish." (source)

EG Koalas of Queensland, Australia, Crocodiles of Florida, America. They are being forced nearer the path of the Baiji, before the inexorable onslaught of the human machine called progress. Too bad there's no tap-dancing specimen with Happy Feet called Mumble to persuade Man to cut them slack.

What I want to say is, before we bring out the weapons of destruction, let's see if we can resolve the problem without bloodshed. Afdter all, you never know if that shot is going ricochet right into the proverbial butt.

Where's a flower power wielder when you need one?

29/1/07 5:52 PM  
Blogger Dawn said...

It reminds me a little of what happened in Farley Mowatt's book "Never cry wolf". There were fears the wolves were killing the caribou so much so that Mowatt was dispatched to find out what was happening. He lived with them for months on end and found out a lot of what we know about wolves. To wit - they are not the solitary, ravenous creatures of myth. Wolves in fact raise animals in packs - and unrelated wolves are able to care for the young of others. Did they kill caribou? Yes. But in very small numbers - and they were very efficient in that they would even suck the marrow out of the bone.

What was it that was killing the caribou then? Man - the caribou were dying out because people were hunting too many caribou. That was small comfort to the wolves though - they were killed anyway.

29/1/07 5:59 PM  
Blogger calsifer said...

I'v not had the pleasure of reading that book. But it is certainly a fact that wolves are being portrayed as the villian in the caribou plight. Alaska has an aerial gunning program, to cut down the wolf as competitor for caribou and moose as human hunter targets: "The purpose of the wolf-killing plan is to cut down the competition for moose and caribou. Hunters have loudly complained that wolves eat too many moose calves, leaving too few moose for sport hunting. " Also, caribou feed on lichen, which maytake hundreds of years to grow. However, lichen growth and supply is being threatened by logging and pollution!

In Canada, the harp seals are being blamed for the cod fishery collapse when it is again Man's overfishing that resulted in it. Also, studies show that harp seals actually eat larger fish that hunt cod fish spawn. Yet, harp seals are still being hunted and killed inhumanely anyway.

As for the Japanese hunting of whales because they are researching the whales, that whales threaten fish stocks and that it is tradition... well, I guess we all that one: Scientific study, my fish!

29/1/07 6:19 PM  
Anonymous Anonymous said...

The fact remains that the removal of cats did more harm than good since the cats were vital in keeping the population of rabbits and rats down. In this sense, how did the eradication of cats benefit the local seabirds? Also there are details we do not know of. Were the seabird populations at crisis level? To what extent did cat predation affect seabird mortality? Ecological disasters like this are not so easily rectified by simply removing certain species from the equation. I do not wish to see the extinction of any species, but nature often does not work the way we want it to, with even introduced species rapidly finding important niches in the environment. In this you can say the cull upset the balance. The new balance with new species factored into the equation, something that the management obviously did not realize.

29/1/07 7:25 PM  
Anonymous Anonymous said...

Anyway, I wonder how is it possible to 'humanely destroy' 2,500 cats? When there are large numbers of animals to be killed, it is likely that there will be great cruelty involved.

"Southeast of South Africa is the small and inhospitable Marion Island (12 miles by 8 miles). In 1949, a group of scientists left the island, leaving behind 5 unneutered cats. By 1975 there were 2,500 cats on the island preying on ground-nesting seabirds. Deliberate infection with feline enteritis killed around 65% of the cats, but the remainder developed an immunity to the disease. Terrier dogs were used to flush out the remaining cats. Between 1986 and 1989 further surviving cats were exterminated by hunting. Finally poison was used to eliminate the remaining cats. It took 16 years of crude and cruel methods to eradicate 2,500 cats in a small, isolated area so how can eradication work where cats from outside can recolonise cleared areas?"
--Sara Hartwell(messybeast.com)

29/1/07 8:37 PM  
Blogger calsifer said...

Good point. That is one heck of a gem of info.

29/1/07 8:46 PM  
Anonymous Anonymous said...

Btw i apologize to mr budak. If I sound as though I don't care about the native wildlife that is not true. However I have been reading up about feral animals in Australia and the methods used to 'control' them are far from humane.

29/1/07 9:31 PM  
Blogger Dawn said...

Yes it took ages - and it was an tiny island in itself. No hinterland at all (even we have a hinterland obviously). It's the only place I know of that 'cleared' the population of cats.

I don't think anyone disagrees with Budak that if there is a serious threat to any native animal something should be done. Nor do I in any way think that Budak thinks killing cats is the first thing to do. I think we are all in agreement that other solutions should always be looked into first - and I am sure with so many people thinking about it, some creative non-killing solution can be found.

29/1/07 10:17 PM  
Blogger Profpig ^@^ said...

Agree with anonymous. They don't humanely cull cats! They SHOOT cats!

"OTHER ANTI-CAT CRUSADERS

A apparently mainstay of the anti-cat crusade is John Walmsley, a conservationist who publicizes his cause by wearing a cat skin on his head like a coonskin cap, its small flat face looking out over his forehead. Walmsley, of Earth Sanctuaries Limited, has claimed that the only good cat is a flat cat (or dead cat) and has shown off the decorative cat-skin friezes on his walls. He has publicly boasted of the number of cats he has shot and of when he killed his first cat, but he has also contradicted these claims and stated that he has never actively killed cats."

TRADITIONAL METHODS OF CONTROL

Traditional control methods include shooting, trapping, baiting (poisoning) and barrier fencing. Trapping is difficult and labour intensive as feral cats tend to be trap shy and. Cats are by nature cautious eaters and do not take baits as readily as do rats, dingoes or foxes. 1080 poison (used against dingoes) also kills cats, but is highly indiscriminate and kills many native species which scavenge the baits. Feral cats may be poisoned with manufactured 1080 Feral Cat Baits (4 g baits containing 6 mg of 1080); the use of Feral Cat Baits is restricted and each application needs the permission of the Agriculture Protection Board.

For more, please go to the below site.
http://www.messybeast.com/auspredicament.htm

29/1/07 10:54 PM  

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