An excess of ragwort?

[Paul mabbott]

Travelling around the country, I've been struck by the amount of ragwort Senecio jacobaea around this year - in fields and roadsides. This in a piece of rough grassland near Clay Cross.


It doesn't seem so bad in the north but everywhere else it seems rather excessive - or is it just me? Could it be due to the weather or is it just becoming more abundant?

[paulchandler6]

Good point, I have noticed far more Ragwort around this year than previous. Hope someone can shed some light. Cheers

[aeshna5]

I've noticed a lot more fields like that this year than previously- a sign of more fields taken out of cultivation + where there is no active management to control this species.

[m1.carson]

Hi people,

Oh dear, I hope this isn't going to turn into another thread about ragwort, and.... never mind, check a locked thread.

Max.

[Paul mabbott]

Originally Posted by aeshna5

I've noticed a lot more fields like that this year than previously- a sign of more fields taken out of cultivation + where there is no active management to control this species.

I don't know about cultivation - the roadsides are not cultivated and my impression, in the past, had always been that overgrowth relates to horse grazing. Now, as in the picture, it seems to be popping up everywhere ....

[Jez]

I have been clearing a 5acre fileld full of raggy this last couple of weeks with me bare hands. All most done! Theres some left hidden inbetween Christmas trees but i think i might just leave those for the cinnabar Moths!

[naturallandscapes]

Anybody pulling ragwort, should always where gloves for handling it. the best way to remove it is to use a tool called a lazy dog. Cutting it just encourages stronger growth the following year.

[Dan Salter]

Most of us know about pulling ragwort and how to handle it etc...i think the point here is why is it in such abundance this year? it has to be something to do with the strang weather we have had...
Jez watch those plants you leave for the cinnebars...id have them out just before they seed mate otherwise youll be back to square one next year.

I too recently read a report ( after plenty of summer days out pulling ragwort with the wildlife trust) that you should indeed wear gloves and probably dust masks as the poisons can get through skin and be breathed in...im probably too late and the damage is done but worth putting into practice for anyone who runs a volunteer group.

Paul im confused by your comment " Horse grazing causes overgrowth"? how do you eman?...obviosuly ideally you wouldnt graze horses in a field with ragwort present or do you mean that if a field is grazed by horses and not sheep...the horses leave it alone so it goes wild while the sheep graze it away controlling it ?

Dan

[Paul mabbott]

Don't know and don't have any statistical evidence but had noticed that ragwort did tend to grow best in horse pastures .... but that's anecdotal not scientific ... and certainly doesn't seem to apply this year.
I suppose that my casual observations would suggest that horse grazing encourages ragwort growth either by selectively destroying competitors of ragwort or by partially eating it while totally consuming competitors? Should be fairly easy to run some scientific studies ....
Cheers, Paul

Originally Posted by Dan Salter

Paul im confused by your comment " Horse grazing causes overgrowth"? how do you eman?...obviosuly ideally you wouldnt graze horses in a field with ragwort present or do you mean that if a field is grazed by horses and not sheep...the horses leave it alone so it goes wild while the sheep graze it away controlling it ?
Dan

[Jez]

The pasture was grazed by sheep until we took the over the land and the sheep had to go! There were also to pigmy ponies that also had a paddock. since there leave i couldn't believe how fast the forna rocketed. maybe the sheep keep the grass down ideal for light to get to ragwort seed and free space for it to grow? Will crack on after your advice Dan. Fortunately since i'm asthmatic and long grass trigger's it off at times i have been wearing a mask regardless to any toxins-relief! Plenty of rain fall this year and a very hot summer last year indeed may have caused far more seed dispersal?

[Dan Salter]

i think its simply that in a horse field...horses dont touch ragwort.( uless its wilted or drid in hay) as they know its harmful to them
Sheep can eat and seem to almost enjoy ragwort so they munch it all away....so in horses fields it goes mad as apposed to sheep grazed fields where it is controlled through grazing..

[wildone]

Have noticed a field on a farm, where deer are the only livestock, that there was a field which looked over grazed and was yellow with ragwort. Does that indicate that deer also either cause ragwort to proliferate or that overgrazing is the culprit?

wildone

[Dan Salter]

Hmm ok im confused now too....ha ha

either way....its blooming everywhere right now !

[Dan Salter]

and like paul stated if overgrazing is a factor then it doesnt ring true for road verges?

[Gytrash]

I've noticed more too this year. In roadside verges, pastures, untenanted allotments and even lawns...

[ceterach]

It is not overgrazing per se that leads to more ragwort. The seeds are more likely to germinate in disturbed earth, hence anything that damages the soil cover such as hooves, forks, Rabbits digging, etc., will increase the opportunity for it to germinate. Overgrazing results in a poor grass sward that is easily damaged, hence more Ragwort.

All the best

[Cotham Marble]

Originally Posted by Paul mabbott

Don't know and don't have any statistical evidence but had noticed that ragwort did tend to grow best in horse pastures .... but that's anecdotal not scientific ... and certainly doesn't seem to apply this year.
I suppose that my casual observations would suggest that horse grazing encourages ragwort growth either by selectively destroying competitors of ragwort or by partially eating it while totally consuming competitors? Should be fairly easy to run some scientific studies ....
Cheers, Paul

Another aspect of how different animals impact on flora relates to how the size of individuals of a species of grazer, the size of herd that is grazed and the seasonality of grazing pattern employed, affects the sward.

In very broad terms th effects can be broken down into two characteristics - mechanical damage caused by animals walking on the sward, and a selective effect dependenant on the closeness of a species grazing habit.

Sheep grazing is very imortant precisely because it favours a consistent grassland environment which supports a relatively stable sward community. Even where the sheep 'paths' break the sward surface, the size of the animals and the shape of the foot rarely causes deep intrusions into the soil.

By comparison, cattle, particularly when kept at a high herd density on wet soils can destroy an existing sward within a few weeks. Horses are rarely kept at the densities seen with cattle, however they are frequently kept on pastures which are heavily degraded because the pasture itself is not used as the primary food source for the horse. In these circumstances the sward is broken in many places providing opportunities for seeds of non sward plants to take hold. Ragwort is very much an opportunist plant and might be expected to be a pioneer of any 'puddled' area of pasture.

CM

[Swallowtail]

Originally Posted by Dan Salter

Most of us know about pulling ragwort and how to handle it etc...i think the point here is why is it in such abundance this year? it has to be something to do with the strang weather we have had...
Jez watch those plants you leave for the cinnebars...id have them out just before they seed mate otherwise youll be back to square one next year.

I too recently read a report ( after plenty of summer days out pulling ragwort with the wildlife trust) that you should indeed wear gloves and probably dust masks as the poisons can get through skin and be breathed in...im probably too late and the damage is done but worth putting into practice for anyone who runs a volunteer group.
Dan

I don't want to intiate a repeat of the recent unhappiness and I don't propose to continue posting at length as I am too busy, but as a professional biologist I do feel that this does need to be answered. There is considerable concern in the entomological community that, while ragwort does need to be controlled, some of the stories that are being circulated are not accurate. Certainly as a scientist I believe a lot of the press stories available leave something to be desired. Some people will be aware of the campaigning work done on this by the Buglife- The Invertebrate Conservation Trust.

Having looked at the toxicity to humans I believe that most of the stuff in the press recently is not valid.
The following link is to an article written by Esther Hegt, who Google tells me is a member of this forum, and Dr Peiter Pelser a researcher on ragwort at Miami University. It is an English language translation of an article which seems to be at least partly based around some of the work that has been published in one of the Dutch journals.

Jakobskruiskruid,feiten en fabels
2) Report on the internet by Dr. Knottenbelt (Liverpool University). This veterinarian is quoted on the internet quite a lot, because he stated, during a debate in the House of Commons, that the toxic substance in ragwort can almost certainly be absorbed through the skin(6). In response to this we contacted Dr. Knottenbelt. Through an email he informed us that there is no scientific proof for his statements. He writes that he himself has suffered liver damage after manually removing ragwort plants. The results of this ‘experiment’ have not been published and, according to us, are not obtained through a good scientific trial.

Through our research about the sources of the reports on the danger of touching ragwort, we conclude that there is no substantial evidence that there is a health risk for people. The amount of pyrrolizidine alkaloids that might be absorbed through the skin is very low and there is no proof that these alkaloids are being changed into a toxic form. Ragwort can cause an allergic skin reaction upon contact; compositae dermatitis(7). This allergy can appear after touching or eating the plant. This allergy is not caused by the pyrrolizidine alkaloids but by others substances that are common in many of the members of the Sunflower family (sesquiterpene lactonen)(8).

[Digiscoper62]

Its very bad up here in Ayrshire this year.
This is the river Garnock looking into Garnock floods, a SWT reserve.
The river banking and reserve is full of it and the next field (out of view) is worse. The local farmer alternates his cattle between the two (the field out of view is ex landfill. Does this not harm the cattle and calf's or do they know better?



cheers

[RobSutton]

Just back from the Outer Hebrides - ragwort everywhere, but then there always is. Up there it seems to be an important and natural part of the Machair Vegetation and the place at this time of year would be less colourful without it. I get the feeling the ragwort question is a bit like the sycamore question, a lot of people are anti-it even though in many situations it's perfectly normal, harmless and proper that it should be there.

[ceterach]

Originally Posted by Swallowtail

Through our research about the sources of the reports on the danger of touching ragwort, we conclude that there is no substantial evidence that there is a health risk for people. The amount of pyrrolizidine alkaloids that might be absorbed through the skin is very low and there is no proof that these alkaloids are being changed into a toxic form. Ragwort can cause an allergic skin reaction upon contact; compositae dermatitis(7). This allergy can appear after touching or eating the plant. This allergy is not caused by the pyrrolizidine alkaloids but by others substances that are common in many of the members of the Sunflower family (sesquiterpene lactonen)(8).

As a professional biologist I would like to specifically address this point but with regard to Dan's comment about volunteers, especially with regard to organised volunteers groups where the question of third-party responsibility often arises.

"there is no proof" is a statement that always sets my teeth on edge, especially when associated with "low" and "might". Unfortunately it is difficult to prove a negative and we have to rely on a balance of probabilities, so although the probability of absorbtion of ragwort toxins is low I would suggest that volunteers always wear gloves when pulling ragwort (if they must, but that is another question).

[Neil Jones]

I am loathe to step into this again but I think we need context . I don't really have a great deal of time to spend on this issue. I would wear gloves when handling poisonous substances of any kind. Most people people would . I don't think that it was Swallowtail's intention to say otherwise. What you need to look at is why this plant is suddenly being singled out.


It is important to understand why the issue is being raised at all. Those of us who are invertebrate specialists will have been reading a different side of this to other people .
I think this particularly applies to those of us who are members of Buglife and are aware of their excellent work on this issue. Some people may even be unaware of the anti-ragwort campaign altogether let alone the effects it is having. Buglife members won't be.

Esther Hegt's splendid Dutch Website, quoted above, has been put together with the assistance and collaboration of around a dozen specialist experts in Holland and the USA. The reason it was done is that she shares the concerns of many of us, including some members of Buglife who have concerns about the validity of the claims that are being made. It is in this context that the comments on that website are made. To put it bluntly there are people out there who are out to eliminate ragwort entirely and they are using every tool at their disposal to make their case. This includes frightening people about the pollen.

Esther's website is set up to provide a thorough scientific understanding and to debunk the more outragious claims inluding those of serious danger to humans.
The link above doesn't give access to the whole site so here it is.

Ragwort, Myths and Facts

The issue about ragwort needs to be looked at in a sensible manner. if we are to control it we need rational evidence on its ecology and we also need to look rationally at whether it needs to be controlled in every circumstance.

The problem is that perceptions about ragwort have been distorted by a series of campaigners in the press, some of whom are clearly not well informed about the science and in particular lack a good understanding of ecology and an appreciation of conservation concerns.

The questions I would ask you to all look at are these. What is the science? Look at the evidence. What would our practice have been before we heard about the campaigning?
Is what we are reading correct? What are the facts?

Take Rob Sutton's lovely picture of the Machair. There shouldn't be anyone in this forum who thinks that ragwort needs clearing in that situation but I could show an example of a Scottish campaigner who has stated that no ragwort should be grown within a kilometer of grazing land. It is quite common to find people who think it is a foreign invader. It is this kind of thinking which is informing the debate.

Thanks to some of Buglife's work the Machair is safe from a proposed Scottish Law that would have forced landowners to control any toxic plant. The anti-ragwort campaign was behind it but plants that would have fallen under its remit would include Bluebells, Daffodils, Foxgloves, and even ,the way it was originally worded ,Oak Trees. They all contain toxins and landowners would have, theoretically, been required by law to clear them.

[Esther Hegt]

Last week we added some new translations on the website, you can look under the button facts and myths
Ragwort poisoning: How does it work?
Pyrrolizidine alkaloid metabolism,
There we explain how the PAs become toxic. Maybe it helps a little

Cheers Esther

Ragwort, Myths and Facts Ragwort, myths and facts

[eeyore]

Originally Posted by ceterach

As a professional biologist I would like to specifically address this point but with regard to Dan's comment about volunteers, especially with regard to organised volunteers groups where the question of third-party responsibility often arises.

"there is no proof" is a statement that always sets my teeth on edge, especially when associated with "low" and "might". Unfortunately it is difficult to prove a negative and we have to rely on a balance of probabilities, so although the probability of absorbtion of ragwort toxins is low I would suggest that volunteers always wear gloves when pulling ragwort (if they must, but that is another question).

I am equally loathe to step into this again and certainly wont be engaging with the argument that was had last time (anyone who is interested in the should they/shouldnt they on rafgowort can view the other thread if they wish.

But i would say that as a proffesional conservation / rights of way manager who regularly uses volunteer working parties I would say that I am with you on this point - The probability is low but as you rightly point out "not proven" isnt the same thing as "defintely doesnt" - I would also point out that it is good practice to allways wear clothes when pulling any plant regardless of its toxicity as I have seen fiborous stems inflict nasty cuts when someones grip slips on a reluctant plant.

Also withour reigniting the argument could I ask why there is significant concern in the entymoligical community about ragwort control as - as is the point of this thread - ragwort is everywhere and cant possibly be considered to be rare or even uncommon.