phil
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Posts: 233
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Post by phil on Jan 14, 2006 15:19:58 GMT
what you mean is will. that somebody has "decided"to group them as species, not that the newts have in any way altered. the definition of a full species is when offspring from an intergrade cannot breed true, and are mules. this is not the case with any of the crested clan.read this en.wikipedia.org/wiki/species-58k-
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Post by Killian on Jan 14, 2006 15:21:36 GMT
Ireland does have three species of amphibians, bufo calamita, L. vulgaris and R. temporaria but I was refering to the two as bufo calamita, L. vulgaris as I read some where that R. temporaria was introduced here.
It is also thought that slow worms were introduced here in Co. Mayo but they may have been a native before this.
It is an interesting though that some populations of "Alien" amphibians in the UK are unexplainable and some people think they may have been there all along and hence a native.
Just a thought if Bears or wolves were reintroduced to Britain would they be considered a native? or is the wild boar now considered an alien?
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Post by willj on Jan 14, 2006 17:26:48 GMT
interesting i wouldn't know, but for birds. the Capercaillie (a huge grouse) became extinct in Britain in the 1800s it is classified as an introduced species now that it has been reintroduced. but they have protection like all other native so "native in all but name" might possible apply to the wolf and bear.
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Post by willj on Jan 14, 2006 17:42:20 GMT
phil, that definition of a species is quite outdates now that DNA has come onto the scene. The fact is the definition of species has been muddied over time. But surely we should define a species as i quote "A single, distinct class of living creature with features that distinguish it from others." what is the use of splitting species that cannot be distinguished in the field. however all four "cristatus" species are sufficiently distinct from one another both in appearence and genetically to justify thei seperation.
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phil
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Post by phil on Jan 14, 2006 18:06:53 GMT
i'll accept that many of my terms and information are probably very dated, after all i began herping about 32 years ago as a small boy. but surely if the fundamental differences between two species or sub-species is so great, then gene pollution would not occur anyway because intergrades if at all possible would be few and far between. and it would also occur where both species naturally overlap. which according to my (dated) information it does not. but i agree entirely with you that caution is the best course of action. and if it is proved that carnifex poses a real threat then it should be removed.after all its only through conservation that we have such healthy pops. of cristatus
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Post by willj on Jan 14, 2006 18:28:39 GMT
the gap between species can be great and it can be smaller. it all depepnds on when they split from each other. in the case of the cristatus lot it is smaller compared to other species, but still large enough to justify elevation to species level, and my more uptodate inofrmation states that there are natural intergrades and the species to interbreed. his may not be in your information because interbreeding between subspecies is less of a deal than between species.
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phil
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Post by phil on Jan 14, 2006 19:51:04 GMT
i understand quite clearly what a species is will. i know that carnifex and cristatus interbreed here and on the continent. what i meant was where the "species" overlap in europe gene pool pollution does not occur, and although there exists an area of higher numbers of hybrids throughout the overlap, the 2 parent species breed true to form with no apparent merging into one type. by the way will, what herps do you have wild in your part of shropshire?
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Post by Killian on Jan 14, 2006 20:46:20 GMT
do either of you know how well the hybrids do? I mean ok they may hybridise and produce viable offspring but both parent species have evolved their own methods to survive in the wild and these are diluted in the hybrid offspring.
I am thinking about mammals here again as I am more familiar with them. In the case of the Liger (male lion x female tiger) the resulting animals is so large it could not catch enough food to sustain it in the wild, its colouration is different from both parent species so it can not hunt in either terrain of the parent species and of course they are infertile.
A hybrid although may posses "hybrid vigor" is really at a major disadvantage, I would be interested to hear how the hybrids do and if they really are a threat to pure species.
of course there are exceptions where the parent species are so closley related that the offspring do pose as a threat to polouting the bloodline like peafowl. most green peafowl in captivity are hybrids within the green peafowl subspecies and worse, also contain some indian blue blood. These birds no matter how long ago the foreign blood was introduced can never really in my opinion be suitable candidates for reintroduction to the wild.
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Post by willj on Jan 15, 2006 15:18:23 GMT
i'm not sure Triturus blasii seems very well established. And about 60% of all Lissotriton montadoni in southern Poland are hybrisied with Lissotriton vulgaris. not to mention that about half Ambystoma jeffersoniamum in New England are thought to have laterale and/or texanum blood in them.
as for herps in my area. we have all three newts in our ponds and bufo bufo and rana temporaria. there are all the reptile apart from the soomth snake and green lizard. but none in our local area for some reason. I've never seen any reptiles in Shropshire (not that i've really looked).
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phil
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Post by phil on Jan 15, 2006 16:16:51 GMT
i built a safeways supermarket in welshpool which is fairly close to you, and in the canal which ran through the site i saw several grass-snakes. another excellent spot for most of the commoner herps reasonably nearby is cannock chase in staffordshire. we are not quite so well blessed in lancashire, and although we can boast all six native amphibs , reptiles seem to like our area a little less and are rarely sighted anywhere except on the coast near formby and ainsdale.
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Post by willj on Jan 15, 2006 18:31:29 GMT
yeah i have family in Welshpool, they own farmland along the canal.
forgot to mention, we have a small colony of mesotriton alpestris in the west of the county near Market Drayton. it's not very big, apparently it's only spread 70m since it was first established in the 70s
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Post by Killian on Jan 15, 2006 22:16:54 GMT
Are the Hyla arborea still established in the New Forest? I heard that collectors destroyed the populatin which is a shame really even though they were introduced (or where they?)
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Post by willj on Jan 16, 2006 8:07:05 GMT
i heard it was a mixture of collectors, Triturus cristatus and australian stonecrop that destroyed them there. but apparently there are some in the London area.
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Post by mark68 on Oct 19, 2006 19:06:10 GMT
A slight change in direction maybe. The introduction of non native (european species) can be very dangerous. It seems to be forgotten that our rarest species (now extinct in UK) of amphibian was the Pool frog. There was a population in london that was 50%/50% native/mainland european. This is now a mixed population including esculenta probably from an escaped esculenta or ridibunda. The original group could have formed the basis for introductions instead of the proposed Swedish stock. At the same site at one time there was breeding population of Hyla arborea, Bombina variegata, as well as Podarcis muralis and Triturus alpestris (both still there). Apart from the alpines I cant see them doing any native species any harm. Has anybody seen the introduced (dorset) population of Lacerta bilineata/viridis
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Alex
Junior Member
Posts: 98
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Post by Alex on Oct 19, 2006 19:59:28 GMT
Has anybody seen the introduced (dorset) population of Lacerta bilineata/viridis They're very local to me, keep meaning to see them someday though. Lot's of Wall lizards round here, and i've been told by a reliable source that Hyla arborea can be found inhabiting a pond in Weymouth.
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