RAUK - Archived Forum - Wall Lizard - Alien Status

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Wall Lizard - Alien Status:

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arrazello
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Posted: 18 Feb 2008
Hello Forum.
I am a third year student of Environmental Science. Currrently I am writing an assignment on alien species and have chosen to argue the case that the alien vs. native species debate is outdated and not always appropriate esp. in light of changing global climate.
I want to draw a comparison between the little ringed plover which has native status (despite the first breeding pair in 1938) and the wall lizard afforded protection in Europe but not in England due to its alien status.
If the wall lizard is not a threat to a native ecosystem, it seems somewhat counterproductive in terms of preserving global biodiversity to not afford it protection in the UK. Can the forum offer an opinion on this?

I am also wondering if the wall lizard can be stated as inhabiting mostly artificially created environments?

Vicar
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Posted: 19 Feb 2008
Hi Arrazello, & welcome.

"If the wall lizard is not a threat to a native ecosystem"

This has not been proved definitively either way, but anecdotal evidence, and recent research suggests a negative impact upon both Sand lizard and Common lizard status.

In the UK it is true that the Wall lizard is most often associated with man-made structures (including quarries) and cliff-faces; although there are exceptions.

Please keep us posted with your assignment !

cheers,

Steve

Steve Langham - Chairman    
Surrey Amphibian & Reptile Group (SARG).
Suzi
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Posted: 19 Feb 2008

If the wall lizard was threatened as a species in another country perhaps we might cherish ours more but it thrives in all its haunts does it not?

The little ringed plover got here under its own steam I presume. Not the case with the wall lizards. The plover has not reached huge numbers has it? I don't think it adversely affects other birds.

I don't quite understand how you can say the alien/native debate is outdated unless you are going to be very selective about what you favour. I'm thinking rabbit, grey squirrel and Canada geese as fairly unwelcome. It would be interesting to hear more of your ideas.


Suz
David Bird
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Posted: 20 Feb 2008
I should think that most people who have travelled around Europe would agree that the Wall Lizard is one of the lizards that does not need European protection status as it is so widespread and so numerous in most of its range. I believe it was put on because it was rare in the north west of its range, edge of range so expected, and at the time the people who were responsible for putting species forward were based in the north west of Europe and trying to get them protected when their own governments were not listening.
Some species Podarcis siculus were also added as they had subspecies which lived on very small islands with very little area and were an isolated population whereas the widespread Podarcis siculus campestriswas and still is extending its range and is threatening endemic species and subspecies of Podarcis siculus where it has been released or accidentally introduced.
British Herpetological Society Librarian and member of B.H.S Conservation Committee. Self employed Herpetological Consultant and Field Worker.
herpetologic2
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Posted: 21 Feb 2008

 

I am a third year student of Environmental Science. Currrently I am writing an assignment on alien species and have chosen to argue the case that the alien vs. native species debate is outdated and not always appropriate esp. in light of changing global climate.

I agree with that to a certain extent as it is human activity which has introduced many hundreds of species around the world, it is also down to our views of what the world should be (species etc) that drives the debate with alien verses natives -


I want to draw a comparison between the little ringed plover which has native status (despite the first breeding pair in 1938) and the wall lizard afforded protection in Europe but not in England due to its alien status.


As with all these bird migrations there may have been a human element to them establishing themselves in the UK - other examples include the collared dove - was that introduced or did it make it to the UK by its own?

I have also come across other species on my travels which are said to have come to the UK through their own steam - Eagle Owls and Cranes - a question often remains were they in fact introductions? and does that really matter?

If the wall lizard is not a threat to a native ecosystem, it seems somewhat counterproductive in terms of preserving global biodiversity to not afford it protection in the UK. Can the forum offer an opinion on this?

It would be interesting to draw on the situation in Jersey where the Wall lizards are suspected as introductions but are afforded full protection under Jersey State Wildlife Laws - All their herpetofauna is fully protected - grass snake, common toad, wall lizard, slowworm and green lizard - I think the palmate newt may be except - here the wall lizards are found on fortifications and other large buildings even one of the fort islands has a population. A study into the genetics of the wall lizards here is looking at where they may have come from or their native status may be supported. 

I am still of the opinion that there are other factors which tip the balance in favour of the wall lizard when native species are present and are found to be declining.

I saw the presentation at the BHS meeting last year regarding the wall lizards and viviparous lizards. The results were interesting and I noted that the viviparous lizards were near cover (scrub, gorse etc) while the walls were near paths and much drier areas of the site (I assume) - perhaps the management of the site needs to be looked iinto alongside the possible bias in the survey results due to the detectability of walls over vivs?

I am also wondering if the wall lizard can be stated as inhabiting mostly artificially created environments?

Mostly artificial habitats - walls, stockades, forts, etc but they do live within cliff faces, rocky outcrops and other more semi natural habitats aswell.

 

J

 

 

 

 


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Davew
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Posted: 21 Feb 2008
Hi - Collared Dove was a totally natural invasion. I don't think there has ever been any suggestion that the current Eagle Owls are nothing more than establishing escapes. Again with the Cranes I think it's sort of understood (but not proven) that the original few were introduced with numbers bolstered by occasional breeding successes and immigrants. Davew39499.4283333333
herpetologic2
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Posted: 21 Feb 2008

Eagle owls are breeding in this country successfully for a number of years - some people say they were introduced or were escapees but there has been a suggestion that they made their own way across the north sea as they have been spotted on oil rigs apparently so it is possible that some have come over - but I also think that this is a potential native species for the UK like the other species which were hunted to extinction - lynx, wolf, bear, beaver etc

Collar doves are suggested that some were escapees from private bird collections in previous centuries.

 

the debates will rage on and on

 

J


Vice Chair of ARG UK - self employed consultant -
visit ARG UK & Alresford Wildlife
Davew
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Posted: 21 Feb 2008

It is very possible that Eagle Owls have come over under their own steam but short of a ringing recovery it would be impossible to tell as they're so common in captivity and some authorites quote the escaped breeding population as 40 pairs+. A bit high in my opinion! It's a very odd situation, apparently the RSPB set up a viewing point for a pair of these birds in Bowland last year. When they had finished breeding "apparently" remains of Hen Harriers were found around the nest with Hen Harriers being the reason the RSPB owned the surrounding moorland. Don't know how true that is? Incidentally some oil companies do release Eagle Owls onto oil platforms to control Starlings which may find there way out there. Surely one would atract another so although I wasn't aware of any oil platform records of this species it certainly seems very likely.

I've never heard that Colared Dove theory before. I don't think escapes would have altered things as the species literally exploded across Europe during the first half of the 20th century and is stil quoted as one of the most amazingly fast colonisations of any bird species.


herpetologic2
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Posted: 21 Feb 2008
Exactly why people alway question the given theory of how they got over here - changes in climate perhaps who knows

I am correct in thinking that the eagle owls was once native to the UK?

anyway the wall lizards in my opinion do not pose a 'significant' threat to our native lizards compared to the other main reasons why our native lizards are declining - which of course is habitat loss due to human activity -

Why spend money controlling a non native when the money can be better spent elsewhere which would actually do some good - habitat recreation on a large landscale scale perhaps would be a more beneficial venture for nature conservation.....

It makes me laugh concerning Ruddy Duck cull in England - when the simple solution to conserving the white headed duck is to cull the small number of ruddies which make their way to Spain etc but no a massice eradication project in the UK is the way to go despite the fact that it is large scale habitat loss and hunting which is knackering the white headed duck population





J



Vice Chair of ARG UK - self employed consultant -
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Davew
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Posted: 21 Feb 2008

Hi - Yes I believe there are historical and or fossil records indicating Eagle Owl in our past.

I totally agree with those points. I don't have the exact figures but would imagine at least a million was spent on the Ruddy Duck cull resulting in more scattered breeding populations and the deaths of several scarce species which to the shooters looked like Ruddy duck and were mistaken for such. Including an actual White-headed Duck, probably an escape but still a major balls up.

I think the important thing is that the public should be made aware of the consequences of releasing these aliens. sounds like a long shot I know but if culls are failing what other options are there.

Just a thought here and legalities aside, ie I know it's illegal but for the sake of argument lets ignore that for now. If future research points to the neccessary control of Wall Lizard why couldn't the animals just be caught and transferred to the various quarries on Portland where there are no Sand Lizards and from where the Wall lizards could never spread?


herpetologic2
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Posted: 21 Feb 2008

Probably a no goer as I believe that the higher powers would want to see animals removed and not released.

It is simple to lay the blame at the Wall lizards door when it could be a host of other factors which are affecting the native populations - genetics, management, micro climate etc

The wall lizards detectablity is reasonably high so it would give the impression that they are taking over when it can possibly be the management regime of the habitat favouring the walls over the viviparous -

J


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arvensis
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Posted: 21 Feb 2008

Another question would be, could all the Pm be removed from somewhere like Boscombe?  Looking at the terrain there it would be difficult even if the go-ahead was given.

Mark


Hampshire Amphibian and Reptile Group.
Vicar
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Posted: 21 Feb 2008
I've always liked the idea of populating Portland with Pms...then introducing Smooth snakes 

Joking aside...Catching the Pm off the Dorset cliffs would be practicably impossible. Anybody who has climbed those cliffs to survey knows just how difficult that terrain is. My guess is that you'd need to remove all the vegetation. They're here to stay.

It may be possible to use barrier methods to halt, or more likely slow, any expansion.

Steve Langham - Chairman    
Surrey Amphibian & Reptile Group (SARG).
Alex2
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Posted: 21 Feb 2008
[QUOTE=arvensis]

Another question would be, could all the Pm be removed from somewhere like Boscombe?  Looking at the terrain there it would be difficult even if the go-ahead was given.

Mark

[/QUOTE]

Hi Mark, 

David Bird may fill you in further on this, but last i heard it was realised that it would be a near impossible job regarding podarcis removal, the terrain surely being the biggest factor. Although Jon states that blaming the podarcis for the dissapearance of the agilis is the simple theory, it's not really a 'simple' theory...It's infact been well thought out, and not kissing backside but Dave is one of the few people you could truly call an expert on European herps so i would personally be inclined to listen to his views. DB, to my knowledge, has worked on those cliffs since the 70's (?) and LA were perfectly viable up until ********** released an initial 50/60 juvenile podarcis there in the early 90's. Now i'm no Sherlock Holmes, but i only see one major factor that's changed on the cliffs since LA were once found in numbers. However, I must admit that up until relatively recent times i wondered if the podarcis were a relict population, but i was quickly set straight. 


Davew
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Posted: 21 Feb 2008

[QUOTE=herpetologic2]
It is simple to lay the blame at the Wall lizards door when it could be a host of other factors which are affecting the native populations - genetics, management, micro climate etc
[/QUOTE]

Just to confirm that I would be totally opposed to any cull or action based on current knowldege.

To comment on a further point made, if the original releaser of Wall Liazrds at Boscombe is known, can't any action be taken against him/her?


herpetologic2
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Posted: 22 Feb 2008
Fine  - We will have to agree to disagree on the simple 'scapegoat' theory

Regarding any action to the person concerned with releasing the animals - probably a tad bit late to get a conviction and even if you did manage to get him/her to the cop shop there is no evidence i.e. actual witnessing the release - though I may be wrong perhaps someone saw the release while they were surveying the sand lizards

J





Vice Chair of ARG UK - self employed consultant -
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arrazello
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Posted: 27 Feb 2008
[QUOTE=Suzi]

I don't quite understand how you can say the alien/native debate is outdated unless you are going to be very selective about what you favour. I'm thinking rabbit, grey squirrel and Canada geese as fairly unwelcome. It would be interesting to hear more of your ideas.

[/QUOTE]

Thanks for all the input.

To answer this question, I would need to post the entire essay so maybe after Friday when it is finished, if you are interested, I could do that. Be interesting to say what the forum think.

My essay starts by discussing

1. The arbitrary nature of the alien vs. native distinction:a) Temporally. b) Spatially. c) Inviability of the idea of a truly native habitat. d) Incomplete natural history records.

It was in this first section that I wanted to bring in the wall lizard and little ringed plover. The little ringed plover did colonise naturally but its colonisation relies on an artificially created habitat. Arguably, this is indirect introduction - facilitated by human activity and not in accordance with the IUCN definition of native.

IUCN defines native species as those occurring within their natural range (past or present) and dispersal potential (within the range it occupies naturally or could occupy without direct or indirect introduction or care by humans)

In contrast, Podarcis muralis, has been assigned alien status and is thus denied statutory protection in Britain. I could find no research stating that it significantly and negatively affected ecosystems.

Both colonisations are a result of habitat alteration. One change is embraced and the other rejected. Such legislation seems counter-active when the overall aim is to maintain global biodiversity. Thus, in 'areas where native ecosystems are not being compromised, unashamed protection, where appropriate, of introduced species may be beneficial to global biodiversity'. 

This, of course falls down if there is no protection of that species (Bern Convention) and I had better find a better contrast.


arrazello
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Posted: 27 Feb 2008

[QUOTE=Vicar]Hi Arrazello, & welcome.

"If the wall lizard is not a threat to a native ecosystem"

This has not been proved definitively either way, but anecdotal evidence, and recent research suggests a negative impact upon both Sand lizard and Common lizard status.

In the UK it is true that the Wall lizard is most often associated with man-made structures (including quarries) and cliff-faces; although there are exceptions.

Please keep us posted with your assignment !

cheers,

Steve
[/QUOTE]

Hi Steve and thanks for your interest and welcome. You mention recent research - have you a reference for the journal?


arrazello
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Posted: 27 Feb 2008

[QUOTE=herpetologic2] As with all these bird migrations there may have been a human element to them establishing themselves in the UK - other examples include the collared dove - was that introduced or did it make it to the UK by its own? I have also come across other species on my travels which are said to have come to the UK through their own steam - Eagle Owls and Cranes - a question often remains were they in fact introductions? and does that really matter? [/QUOTE]

Certainly, the establishment of the little ringed plover seems to have been significantly aided by artificial environments.

I agree with you when you say - does that really matter? I don't believe it does. Despite the massive ongoing harm caused by alien species: they should not be thought of as damaging species per se.  Precise delineation of a natural range is unrealistic when we consider that environmental factors are in flux and climate change will redefine the range of many species. What will we do - send them back? Or accept that things change?


arrazello
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Posted: 27 Feb 2008

[QUOTE=herpetologic2]anyway the wall lizards in my opinion do not pose a 'significant' threat to our native lizards compared to the other main reasons why our native lizards are declining - which of course is habitat loss due to human activity -

Why spend money controlling a non native when the money can be better spent elsewhere which would actually do some good - habitat recreation on a large landscale scale perhaps would be a more beneficial venture for nature conservation.....
[/QUOTE]

Interesting to see you write this since (beyond the arbitrary nature of an alien/native distinction) another of my essay arguments relies on how the majority of research has neglected to investigate the interconnectivity of native habitat loss and alien species abundance. Much research seems to treat these as independent factors. Simple correlations between native decline and alien dominance is not proof of causation. Degraded environments are so much more susceptible. 


- Wall Lizard - Alien Status

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