Introductions

[Neil Jones]

In message <01be7ecc$118f8880$0ee11ac3 at e5q5n1> "Nigel" writes:
> 
> 
> Neil Jones <Neil at nwjones.demon.co.uk> wrote in article
> <923229637snz at nwjones.demon.co.uk>...
> > In article <922325426.25410.957 at excite.com>
> >Unfortunately it is not very easy to do at all.
> > The evidence from the UK is that with the exception of a few species
> > introductions of this kind do not work well at all. 
> > It isn't just a matter of releasing a species in a place that _looks_
> suitable.
> > It requires a great deal of study first. 
> 
> But what the hell, it doesn't do much harm to give it a try does it?

It can do a great deal of harm with some species.

 If
> you've got the time and effort give it a go. If it doesn't work then you
> can revert to why. Neil would probably be horrified to know that I have a
> healthy population of Black Hairstreak (S. pruni) thriving in the woods
> behind my house in Southern Hampshire, UK. I just let them go and that was
> that! OK this doesn't work with most species, but often habitats change and
> become suitable again if only the butterfly could reach it.
> Nigel

You have picked one of the few examples where it does work. For those
from outside the UK. This species is confined to a narrow band of colonies
in the middle of England. It is believed that this may be due to historical
management of the woodlands which were managed on a longer coppice cycle
in this area. 
 
I am not horrified since this is not going to cause problems with conserving
the species. The conservation of species is my main concern.
This practice of carrying out introductions is causing problems with
other species. Particularly the Marsh Fritillary. It has been well established
with this species that introductions DO NOT WORK WELL. Yet misguided people
persist in releasing them. This produces temporary colonies which makes
the butterfly seem more common, diverts conservation effort etc.


There is a well documented example of a Black Hairstreak introduction in 
Surrey (Southern England) which lasted for many years. I understand that
this colony spread but has not died out. Habitat destruction may
have played a part. 

-- 
Neil Jones- Neil at nwjones.demon.co.uk http://www.nwjones.demon.co.uk/
"At some point I had to stand up and be counted. Who speaks for the
butterflies?" Andrew Lees - The quotation on his memorial at Crymlyn Bog
National Nature Reserve