Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: margaret on 25/03/2006 09:20:44
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Do other countries have invasive species that do as much damage as possums do in NZ? We have 70 million possums that chew their way through tonnes of leaves, fruit, flowers every night. They are driving some native species to extinction. This can be by direct competition or domino effect eg eating fruit that native birds normally eat OR by a cascade effect, eg they eat the leaves and the birds that need the seeds don't get them because the tree is so sick it does not flower. Once possums find something they like they just keep eating it until it disappears. Unfortunately our possums are bigger and healthier than in their native land and breed all year round.
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I suppose many people would regard humans as the ultimate invasive species.
Clearly, New Zeeland, being a fairly small, and also fairly isolated, ecosystem would be more dramatically effected by invasive species than environments that are larger (and thus more resilient), or less isolated (and thus used to a regular and steady flow of flora and fauna invading it).
I believe there other small island ecosystems that are even smaller than NZ, and thus even more vulnerable; although few have substantial human populations, let alone amount to nation states in their own right.
George
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We had a minor disscusion on this b4
http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=1612
Michael
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i guess i don't know how bad the possum problem in NZ is. and as "someone" pointed out, I'm sure that an isolated island like NZ is more suceptable to such problems; but for discussion's sake I'd like to mention just a few of the invasive species that cause headlines in my neck of the woods:
-sea lampre
-zebra muscles
-milfoil
-crap, I'm blanking on the name of this one. some sort of purple flower that you see all over the highway sides
-Asian beetles
Are YOUR mice nude? [;)]
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quote:
Originally posted by MayoFlyFarmer
i guess i don't know how bad the possum problem in NZ is. and as "someone" pointed out, I'm sure that an isolated island like NZ is more suceptable to such problems; but for discussion's sake I'd like to mention just a few of the invasive species that cause headlines in my neck of the woods:
-sea lampre
-zebra muscles
-milfoil
-crap, I'm blanking on the name of this one. some sort of purple flower that you see all over the highway sides
-Asian beetles
Are YOUR mice nude? [;)]
Is the purple flower wisteria? That stuff is a nightmare.
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quote:
Originally posted by margaret
Do other countries have invasive species that do as much damage as possums do in NZ? We have 70 million possums that chew their way through tonnes of leaves, fruit, flowers every night. They are driving some native species to extinction. This can be by direct competition or domino effect eg eating fruit that native birds normally eat OR by a cascade effect, eg they eat the leaves and the birds that need the seeds don't get them because the tree is so sick it does not flower. Once possums find something they like they just keep eating it until it disappears. Unfortunately our possums are bigger and healthier than in their native land and breed all year round.
That is an incredible figure Margaret. Presumably there are culls yes ?...perhaps they should declare an all year round hunting season !
!...Are they equally in numbers on both islands. It must be like a plague !
We've all seen the infestations of rabbits and mice but nothing on that scale I think. Perhaps rather than culling they should utilise sterilization procedures. But how long would that take to have any effect ?..I don't suppose you could sterilise enough to keep up with the birth rate unless there was a way to deliver a remedy en masse.
OH !..and welcome to the site Margaret. [:)]
Men are the same as women, just inside out !
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Rhododendron invasion is one serious problem in the U.K. it blankets the ground rapidly and smothers the growth of native trees and shrubs, leaving toxins in the soils. The cover is so dense, native animals and insects cannot inhabit areas affected by rhody's. But the solution is even more complicated, usually involving herbicides (weed Killers) which are often more toxic than the Rhody and cause huge problems when leeching into ground water. Burning and hacking is a very labour intensive solution, which unless carried out on a huge scale will not even begin to address the rapid self seeding of this prolific plant.
"The explanation requiring the fewest assumptions is most likely to be correct."
K.I.S. "Keep it simple!"
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New Zealand will be more succeptable to alien invasions as it has been harder for them to happen in the past - it is and allways has been an island surrounded by a lot of sea, so there has been less competition in the past, so the native species are less competitive on average. Essentially globalisation is happening to wildlife as well as businesses.
Saying this alien invasions are often not as bad as they first appear - it takes a while for the local predators and parasites to adapt, for example cane toads have poisonous backs and crows have now learnt to turn them over and eat the juicy bits underneath, also snakes have got smaller so they can't swallow a grown cane toad which would kill them, but they can take a young one which is less poisonous... in a few years they will probably evolve immunity to the poison and be able to take the large ones again.