In article ,
Malcolm wrote:

I would add Rhododendron ponticum as an ecologically serious nuisance
over the majority of the country, with Heracleum mantegazzianum (giant
hogweed) perhaps the nastiest for humans.

Both are factually wrong, though such claims are made for both,
mostly by misinformation rags like the Daily Wail.

Rhododendron ponticum will not even establish itself in much
of the country,

Perhaps before you make yet more didactic statements you should look at
the distribution map for Rhododendron in the BSBI Atlas, which shows it
as occurring in 1787 out of the 2852 10-km squares in Britain, being
absent from mountain tops and parts of Central and East Anglia where
presumably the soils are not sufficiently acidic. For comparison,
Japanese Knotweed occurs in 1877 squares, again absent from high ground
and also much of northern Scotland.

Perhaps before you post again you should learnt the difference between
occurrence and establishment. Indeed, there are plenty of plants that
occur widely, but have established nowhere (usually referred to as
'common casuals').

and is much less of a problem even where it is
invasive than many people claim.

Perhaps if you lived in areas where it is a significant problem, much of
Scotland, the Lake District, etc., you would not be so complacent. It
can be just as big a nuisance as knotweed.

Perhaps if you kept your eyes open, you would notice the difference.
Many people claim that it is always a major problem where it occurs,
and that is very clearly not the case.

I have never seen more than a
patchy clump very far from the west coast, though there may be a
few more solid ones in places.

*You* may not have seen this, but others have. Perhaps it depends on how
well travelled you are.

Probably more than you. I have many times asked people to provide
me with information of where it is causing a problem away from the
west coast, and rarely had an answer. I have also deliberately
looked out for the phenomenon over several decades and, while I have
seen where R. ponticum has established itself, I have never seen it
showing any signs of being dominant away from the west coast.

A statistical analysis of my observations is that it is definitely
rarely a major problem in the areas away from the west coast in
the areas I have seen it, and may never be.

Since you claim that you know of such locations, would you care to
inform us of exactly where?

Also, it isn't a major problem
(no more than, say, sycamore, ash etc.) where the woodland has
established a canopy (or even can do so?), as much of Cornwall
can witness.

It is without doubt a "major problem". It might not be in Cambridge, but
believe me it most certainly is in many other parts of the country. And
I would be happy to show you large areas of woodland, complete with a
canopy and complete with a dense understorey of rhododendron.

Without evidence that it is crowding out other species out under such
circumstances, it is ridiculous to describe that as a major problem,
except to your prejudices.

The problems with Heracleum mantegazzianum are grossly overstated,
as the actual injury statistics show. I can't currently find a
link, but I previously saw one that made it clear that the
hysteria was almost entirely tabloid-driven. Yes, it can cause
serious harm, but so can lots of other things.

I didn't say Giant Hogweed caused "serious harm", but did say that it
was perhaps the nastiest invasive for humans. i note your inability to
find your link.

I note your childish response, and similar failure to find any link
on the incidence of harm due to H. mantegazzianum.

I hope you wouldn't regard the Centre for Ecology and Hydrology as part
of the tabloid press and that you won't contradict what their leaflet on
the plant states, and in particular the last comment which they have
chosen to put in caps:
"WARNING
The sap of giant hogweed contains a toxic chemical which sensitises the
skin and leads to severe blistering when exposed to sunlight.
THIS REACTION CAN RECUR FOR MANY YEARS"

Well, yes, I can. That is misleading, to the point of being false.
It would be correct if it had said "can sensitise" and "can lead".

Yes, it can do that, but it does not necessarily do that - and, no,
I don't know why it sometimes does and sometimes doesn't. I have
had a lot of its sap on my skin, on a hot, sunny day, and had no
reaction. I know other people who have had the same experience.

Also, I suggest that you look up the effects of some introduced
plants (especially oil seed rape) on asthmatics. Or do you regard
their misery (and, sometimes, death) as unimportant?


Regards,
Nick Maclaren.

On 19/08/2014 16:31, Nick Maclaren wrote:
Since you claim that you know of such locations, would you care to
inform us of exactly where?

There are large areas of it in the woods around where I used to live, in
Bracknell. "Rhoddy bashing" is a common volunteer task.

That's about 100 miles from any west coast.

Andy

In article ,
Vir Campestris wrote:
Since you claim that you know of such locations, would you care to
inform us of exactly where?

There are large areas of it in the woods around where I used to live, in
Bracknell. "Rhoddy bashing" is a common volunteer task.

That's about 100 miles from any west coast.

Yes, but how harmful is it, really, in that location? The Rhoddy
bashing could be because people claim that it is harmful, rather
than because it actually is.

The point is that we have many species that establish local
dominance, but that is not an ecological problem. What is the
problem is when they start eliminating whole ecological niches.
Examples include brambles, bracken, gorse, sycamore, and a lot
more. Indeed, I remember when bracken was being demonised in
the same way that R. ponticum is today.


Regards,
Nick Maclaren.

On 20/08/14 13:57, Malcolm wrote:
Well, I know which I would rather have in terms of diversity. Willow,
blackthorn, gorse and brambles offer a great deal more diversity for
food, nests, shelter, etc., to birds, butterflies, bees, small mammals,
etc., than "a mass of R. ponticum"?

And the kids who might have played there are now nicking bits off your car.

There's plenty of diversity overall for the wildlife - one hilltop won;t
kill them.

In article ,
Tim Watts wrote:
On 20/08/14 13:57, Malcolm wrote:
Well, I know which I would rather have in terms of diversity. Willow,
blackthorn, gorse and brambles offer a great deal more diversity for
food, nests, shelter, etc., to birds, butterflies, bees, small mammals,
etc., than "a mass of R. ponticum"?

And the kids who might have played there are now nicking bits off your car.

There's plenty of diversity overall for the wildlife - one hilltop won;t
kill them.

R. ponticum has been a native plant in the past, and there are lots
of other plants that establish uniform stands but are not demonised
for doing so. The issue is whether something will eliminate whole
ecologies, over most of their range, and not whether an individual
area will turn into a uniform stand.

There is little doubt that R. ponticum will do that to SOME of the
ecologies in SOME parts of the UK, but its fanatical opponents
claim that it will do it far more widely than is justified by the
evidence. It needs a fairly high rainfall and a neutral to acid
soil, which is why it is a serious problem in the west and a
negligible one in most of the limestone and chalk areas and east.

Also, most people forget just how new, man-made and mutable Great
Britain's ecological landscape is - the establishment of a new one
is neither unusual nor harmful in itself. To repeat (as I will be
misrepresented, anyway), there is strong evidence that it is a
danger to other ecologies in the west, and to isolated examples in
some other places.

I have many times asked R. ponticum haters to point me in the
direction of hard evidence for its harmfulness away from the west,
and the invariable response has been references to their own
polemic and unsupported claims that mere occurrence is harmful
(i.e. pure prejudice).


Regards,
Nick Maclaren.

On 20/08/14 19:39, Malcolm wrote:

In article , Tim Watts
writes
On 20/08/14 13:57, Malcolm wrote:
Well, I know which I would rather have in terms of diversity. Willow,
blackthorn, gorse and brambles offer a great deal more diversity for
food, nests, shelter, etc., to birds, butterflies, bees, small mammals,
etc., than "a mass of R. ponticum"?

And the kids who might have played there are now nicking bits off your
car.

Well, maybe where you live, but not here. And do you really think that
today's kids would rather be out playing in a rhododendron thicket than
on their electronic devices?

There's plenty of diversity overall for the wildlife - one hilltop
won;t kill them.

A strange attitude, if I may say so. And one that I wouldn't like to see
adopted widely.


Not really - I was taking the stance that the human kids are also part
of the ecology. If the hilltop as was was interesting to them, then it
serves a good purpose.

As to the plating on their devices, well without the hilltop, they have
one less reason not to.

I'm all for responsible stewardship of the planet - but that includes it
benefiting humans.

In article ,
Malcolm wrote:


Perhaps if you kept your eyes open, you would notice the difference.
Many people claim that it is always a major problem where it occurs,
and that is very clearly not the case.

It is very clearly the case in my experience.

That indicates how limited your experience is.

I somehow doubt that given that I have been an active field biologist
working on birds all over (and I mean, all over) the country, whereas
you, or so I was told, were a paper pushing clerk in a computer centre,
but never mind, it is impossible to prove.

I like it! Your delusions are impressive.

A statistical analysis of my observations is that it is definitely
rarely a major problem in the areas away from the west coast in
the areas I have seen it, and may never be.

A "statistical analysis"???? Of whose data and by whom?

Of the data I have observed, and by me. As you could check,
I am a statistician, albeit rusty.

Since you claim that you know of such locations, would you care to
inform us of exactly where?

Come to Scotland.

I do regularly, and I have observed the converse of your claims.

I also note that, as usual, you are not prepared to be corrected or to
ever admit you are wrong but instead concoct pseudo-arguments to support
your original false claim that Japanese knotweed was the "ONLY" (your
emphasis) "vascular land plant that has made itself an ecological or
otherwise serious nuisance over the majority of the country.", which is
patently not true.

What is it about the meaning of the word "majority" that you do
not understand?


Regards,
Nick Maclaren.

In article ,
Malcolm wrote:

I somehow doubt that given that I have been an active field biologist
working on birds all over (and I mean, all over) the country, whereas
you, or so I was told, were a paper pushing clerk in a computer centre,
but never mind, it is impossible to prove.

I like it! Your delusions are impressive.

I was informed of this by a colleague of yours when you used to post
here using a university e-mail address and signing yourself
"Nick Maclaren,
University of Cambridge Computer Laboratory"

That was shortly before you were told that contributing to a gardening
newsgroup wasn't really part of your employment!

Really? Your delusions are REALLY impressive! I used to attach
my contact information for all postings, true, but even you should
notice that I am still posting using my university account, as I
have done for some three decades - previous to that, I used a
departmental one. Unlike some people, I feel no need to hide any
aspect of my public life.

And I have never been told what you said I was, neither in so many
words nor anything that could be construed as such. Making such
contributions always has been an accepted academic liberty (perhaps
even a right) and not a responsibility.

But thank you for clarifying a matter of some while back.


Regards,
Nick Maclaren.