Invasive animals in your area

[Simon Hampel]

have you got some references to back that up? The only wild lovebirds I have ever heard of in Australia, apart for escaped/released individuals, are some small and very short-lived colonies many decades ago (e.g. near Perth).

Perhaps I overstated things a little - I've not seen or heard of significant feral populations - but I've certainly seen enough of them in the wild in the wheat-belt region of South Australia. Most of these would likely be escapees - I have no evidence to support the existence of "colonies" ... I only assumed as much.

My father grew up on a farm in South Australia's Riverland area - near the SA/Vic border, where his nephew still farms wheat and cattle. I've heard my father and uncles talk about Lovebirds as a pest over many years - but I'm not sure what kind of numbers they are referring to and whether you could consider them "colonies" or just small groups of escapees.

Their farm is certainly far enough away from large population centres to indicate that perhaps it is more than just an occasional escapee causing problems.

I found this report from 1985 online - http://www.birdssa.asn.au/saopdfs/Volume 29/1985V29P192.pdf

... and a quick Google search found quite a few government documents identifying the species as a pest to be concerned about - but that may be more pre-emptive in response to their pest status in farming regions of their native countries and fears that if colonies were to establish themselves here, it could cause similar problems.

I will have to ask my father for his experience with wild Lovebirds and see if he or my uncles have any further anecdotal evidence about Lovebird colonies in South Australia.

 

[Chlidonias]

it certainly wouldn't surprise me if lovebirds established populations in Australia: many parts are similar to their original homes in Africa. But I haven't heard of any successful long-term colonies which are known officially.

 

[khakibob]

It would be interesting to see folks thoughts on a definition of "Invasive species". Down here we are using a flawed indicies to establish "invasiveness" its very subjective in its questions & lacks rigour when applied outside the office. It seems anything that is non indigenous these days is branded invasive. Be it high or low risk its called invasive.

Cheers Khakibob

 

[ThylacineAlive]

It would be interesting to see folks thoughts on a definition of "Invasive species". Down here we are using a flawed indicies to establish "invasiveness" its very subjective in its questions & lacks rigour when applied outside the office. It seems anything that is non indigenous these days is branded invasive. Be it high or low risk its called invasive.

Cheers Khakibob

Well whether low or high risk it's still a non-native species that's dug itself in to the local ecosystem.

You know technically the term "invasive species" refers to any species that does well in its habitat and is able to succeed and reproduce so really all species are invasive species.

~Thylo

 

[Simon Hampel]

Well whether low or high risk it's still a non-native species that's dug itself in to the local ecosystem.

... and more the point, an ecosystem is usually finely balanced between food sources, predators and such.

Introducing a new external factor (organism) into that ecosystem which is able to thrive is typically going to do so at the expense of existing organisms.

Whether it is simply eating food that native organisms would normally consume, or if it is more destructive or a predator of native organisms (and thus denying natural predators access to that food source), it is going to be invasive to some degree - almost by definition.

I guess it comes down to some rationalisation or economic cost as to whether we humans consider it "invasive".

 

[nanoboy]

I interpret 'invasive' to be 'introduced by man and non-native'.

Do species invade new territory on their own, or is it all related to man-made factors like habitat destruction, global warming, pollution etc?

 

[zooboy28]

I interpret 'invasive' to be 'introduced by man and non-native'.

Do species invade new territory on their own, or is it all related to man-made factors like habitat destruction, global warming, pollution etc?

I interpret invasive to imply a species that is "worse" for its new environment than other introduced species. Obviously no introduced species is ideal, and it would be better if there were none. But there is definitely a scale on which introduced species sit, that ranges from minimal impact to maximum impact. For example, in NZ, possums are major invasive pests, while I don't know of any real impact caused by pheasants. I think "introduced" is a better term for all species, while invasive should be used for introduced species with more serious impacts.

Of course species invade new territory on their own, how else would they exist anywhere? In recent times, many species are believed to have naturally colonised NZ, e.g. silvereyes and white-faced herons (I think). Pelicans arrived in NZ last year, and while they haven't established yet, they may do so.

Interestingly, some species may have been arriving in NZ for thousands of years, but have only recently been able to establish populations now that humans have altered the environment. Given that they wouldn't be here without human interference, does this make them introduced?

 

[nanoboy]

I interpret invasive to imply a species that is "worse" for its new environment than other introduced species. Obviously no introduced species is ideal, and it would be better if there were none. But there is definitely a scale on which introduced species sit, that ranges from minimal impact to maximum impact. For example, in NZ, possums are major invasive pests, while I don't know of any real impact caused by pheasants. I think "introduced" is a better term for all species, while invasive should be used for introduced species with more serious impacts.

Of course species invade new territory on their own, how else would they exist anywhere? In recent times, many species are believed to have naturally colonised NZ, e.g. silvereyes and white-faced herons (I think). Pelicans arrived in NZ last year, and while they haven't established yet, they may do so.

Interestingly, some species may have been arriving in NZ for thousands of years, but have only recently been able to establish populations now that humans have altered the environment. Given that they wouldn't be here without human interference, does this make them introduced?

Haha. I meant in recent times - I should have said that.

Hmmm.... I suppose that if they arrive on their own then they cannot be considered "introduced" per se.

 

[Chlidonias]

if they arrive in recent times they are self-introduced (which falls under "native" but with a more recent implication). For example, in NZ white-faced herons, silvereyes, spur-winged plovers, welcome swallows, coots -- all self-introduced from Australia last century.

Introduced is only used for species actually brought to a non-natural area by human agency.

Invasive is not the same as introduced. Invasive species are introduced species which have negative impacts on the native eco-systems on a large (or even on a local) scale. Invasive species can potentially also be native animals for which natural controls have been artificially removed by humans (or native animals expanding their ranges through modification of habitats by humans).

 

[nanoboy]

if they arrive in recent times they are self-introduced (which falls under "native" but with a more recent implication). For example, in NZ white-faced herons, silvereyes, spur-winged plovers, welcome swallows, coots -- all self-introduced from Australia last century.

Introduced is only used for species actually brought to a non-natural area by human agency.

Invasive is not the same as introduced. Invasive species are introduced species which have negative impacts on the native eco-systems on a large (or even on a local) scale. Invasive species can potentially also be native animals for which natural controls have been artificially removed by humans (or native animals expanding their ranges through modification of habitats by humans).

Cheers. That makes sense - except for the last sentence in bold. Surely those would be called "pest" species rather than "invasive" if they are native and their numbers increase. With the reduction in forests and increase in grassland, I can't see the Eastern Grey kangaroo being considered "invasive" if there are just lots more in a given area. Or is what you posted an official definition?

 

[Chlidonias]

Cheers. That makes sense - except for the last sentence in bold. Surely those would be called "pest" species rather than "invasive" if they are native and their numbers increase. With the reduction in forests and increase in grassland, I can't see the Eastern Grey kangaroo being considered "invasive" if there are just lots more in a given area. Or is what you posted an official definition?

I think I worded it badly. Emphasis should be on the "potentially". Normally native species wouldn't be considered invasive. But as an example if habitat modification forced or allowed native animals to expand into areas they normally wouldn't have occupied they can be invasive.

The key point in "invasive" is that the animal or plant is outside it's natural range, and has a detrimental effect on the area it now occupies.

 

[Simon Hampel]

There are probably some good examples of native animals which have thrived in populated areas that otherwise would not be found in the area, or at least, not in the numbers they are now found.

Not sure if we could call that invasive though - given that the ecosystem has already been "invaded" by humans, I'd more call it "adaptive".

Similarly,

 

[WLV30SAS]

First of all I love this topic because I work in the removal of Invasive American Bullfrogs in Northern New Mexico, and let me tell you it is amazing how much damage these frogs can do, their tadpoles over and outcompete the native amphibians, and the adults eat anything they can fit in their mouthes. Besides the frogs, their are invasive Cat-tail plants, Feral Hogs, Canadian Geese, and sevral invasive species of Crayfish in this area. A little North from where I work there are invasive Wal-eye fish, and invasive carp. The Wal-eye issue is big because they are killing off the local Salmon, and the carp have caused a man made Lake in Las Vegas, New Mexico to shut down.

 

[Norwegian moose]

In Norway is maybe the most famous introduced animal the muscox. Many people do not even now that they are introduced though. Yes muscoxen lived in Norway in the ice age, about 10,000 years ago, but the ones that live here now are descendants from animals that was introduced from Canada, only about 70 years ago. All the muscoxen in Norway live on a mountain range called "Dovrefjellet", that is about an hour from where I live.

Another recent occupant is the wild boar. The wild boar in Norway have all immigrated from introduced populations in Sweden, and although they are alowed to live free in Sweden, they are unwanted in Norway so you do not need a licence to shoot them.

Other animals that have been introduced or immigrated in or into Norway with more or less luck is the raccoon dog, coati, spanish slug, red king crab and one species of frog that was relased by a boy that had taken it with him from an vaciation in Poland.

But maybe the most unbeliveable introducion of all happened in the 1930s when 9 kingpenguins, 13 macaroni penguins, and 10 gentoo penguins was relased in Northern-Norway in a place called Røst and Gjesvær. A man called Carl Schøyen covinced the Norwegian wildlife services to introduce the penguins. Some of the penguins survived for a while, up to a couple of years, but most of them died very fast, and all the penguins are dead today. The project did not suceed.

 

[Monty]

I have been doing my best to remove invasive species last weekend. Our Hunt Club had a fox drive to remove as many foxes as we could over the weekend. There is now 174 less invasive foxes in this area.

Feral animal culling

 

[Monty]

Only shotguns permitted for safety as we have a lot of people in a small area. Most of the foxes are chased out of rice stubbles by walkers and the shooters cover the edge in the direction we are scaring, which is also the downwind side. We have a lot of inexperienced shooters from out of the area who belong to our club, which makes organisation difficult. I have been involved in this fox drive for at least 5 years and do a bit of organizing paddocks and directing shooters and walkers where to go. Makes it hard for me to actually do any shooting.

 

[khakibob]

Sounds like a blast Monty - literally

What was your weapon of choice/

Don't get him started! lol

It'll be 9.3 this & 9.3 for that & 9.3 for zombies,etc etc,etc. LOL

By the way, great job Monty & great article too.

Cheers Khakibob

PS. Getting any rain?

 

[tschandler71]

Here in Alabama? Yeah its dried up compared to the flood the middle of the month was. But we are supposed to have a front move through this week, also hit our first 90s yesterday around here. Good time to go nocturnal and hang around the central unit with a glass of sweet tea or a beer. Especially since my only "jobs" until August (when school starts back) involve yard work, the garden, cows, and "bass fishing" (and yes that is serious work)

 

[khakibob]

I see you've become a parent again. Do they calve without many problems?

I'd expect that all the whitetail would have just started to squirt out in your area too.

Cheers Khakibob

 

[tschandler71]

I see you've become a parent again. Do they calve without many problems?

I'd expect that all the whitetail would have just started to squirt out in your area too.

Cheers Khakibob

yeah they "calve" wild still. They are unpredictable where you can't treat them like cows. But between them calving wild and my cattle being good calvers naturally (one of the best things about Herefords) Calving season is not a big of a headache as it is for some people.