From Woodland to elsewhere

[Jack Harrison]

In the past 60 years several species seem to have abandoned woodland habitat or have become much less common in woods. But is some instances, different habitats have come to the fore. Doubtless my thoughts will be challenged and modified by others.

Dingy and Grizzled Skippers used to be quite common in open areas within woods. Certainly they do still occur there (eg Tugley/Oaken Woods) but today the prime habitat seems to be brownfield sites, eg old railways, quarries.

Silver studded Blue. I can’t remember the exact locality after all these years, but after watching SSBs in Ashdown Forest (perhaps a misnomer – it’s largely heathland) I found them quite deep in some woodland along the sandy open rides.

Duke of Burgundy. In the 1960s/70s it was a woodland species (Bernwood, Somerford Common, Rewell, Groveley, Great Ridge Wood for example) but certainly with some colonies on downland. Today just a few carefully protected woodland colonies remain.

Purple Emperor no longer seems to be confined to woodland. In the Sussex report for 2009 Neil Hulme reports many sightings along the South Downs in fairly open habitats and he suggests that the species is far less restricted to lowland woodland than it used to be.

Dark Green Fritillary used to occur not only in open habitats such as downland, coastal dunes but also in extensive woods, eg Kingspark (Sussex) Guiting (Gloucestershire). But I know of no woodland colonies today.

High Brown Fritillary was traditionally thought of as a woodland species (I saw in North Norfolk woods in the early 1950s)that also occurred on bracken covered hillsides. Again I know of no woodland colonies today.

Marsh Fritillary is today virtually confined to open areas such as downland. It used also to be a species of damp woods, eg Somerford Common, Wiltshire.

Grayling – like SS Blue, could be found along sandy woodland rides (eg in woods to west of Waterlooville, Hampshire) in addition to what we today think of as typical habitats, eg downs, heathland.

Wall Brown – not unusual to see in woods 50 years ago but this is a peculiar species as it has become scarce in many areas except near the coast.

Puzzling.

Jack

[Padfield]

Graylings are still abundant in heathery rides in East Suffolk woodlands. They also fly on (what is left of) the heaths and along the sea shore, but to get my annual fix of British graylings I go to Rendlesham Forest, where they can be seen in their dozens in one field of vision. I've been out of the country too long to comment on any of the others.

Guy


(August 15th 2010, Rendlesham Forest)

[selbypaul]

I heard a rumour that they were now extinct at the location, but in 2008, High Brown Fritillaries were still in Dunsford in Devon (an open area of bracken within some quite extensive woods).

[jenks]

Interesting observations. At the risk of appearing to be pedantic, High Brown Fritillary can still be found on at least 1 bracken covered hillside in Vale of Glamorgan at the edge of woodland. Dark Green Fritllary can be seen in the copses and adjoining dunes at Kenfig NNR. Marsh Fritillary can still be found in boggy fields and old colliery sites near Nelson, Bargoed, Trethomas, Tonyrefail, Aberdare and Hirwaun, all in Glamorgan. And of course there is the Cross Hands, Carmarthen, site , which is an area of boggy fields managed by Butterfly conservation. God knows we have enough rainfall in Wales to keep us supplied with boggy fields. All we need to do is stop people from building on them, and then complaining when their houses suffer from rising damp ! It has always surprised me that this fritillary is found in 2 very different types of habitat; boggy fields and chalk downland.

Ah well, I`m just pleased if they all survive, somewhere, and brighten our spring and summer.

Blwyddyn Newydd Dda (Happy New Year) to all those who view this site and contribute to butterfly conservation.

[Jack Harrison]

Jenks:

At the risk of appearing to be pedantic, High Brown Fritillary can still be found on at least 1 bracken covered hillside in Vale of Glamorgan at the edge of woodland. Dark Green Fritllary can be seen in the copses and adjoining dunes at Kenfig NNR. Marsh Fritillary can still be found in boggy fields and old colliery sites

I probably didn't make myself clear enough in my original posting. By woodland, I meant places where the predominant vegetation is a mixture of trees of all ages and height, eg Bentley Wood, Rewell Wood. I did actually mention HB Frit as occurring on bracken covered hillsides. And I should have included the boggy sites for Marsh Frit but these are not what I would term woodland.

It's the loss from or scarcity in pure woodland that is puzzling.

However, I am pleased to hear from Padfield about east Suffolk sandy woods still having Graylings - now on my must-visit list next summer.

Jack

[David M]

Interesting observations. At the risk of appearing to be pedantic, High Brown Fritillary can still be found on at least 1 bracken covered hillside in Vale of Glamorgan at the edge of woodland. Dark Green Fritllary can be seen in the copses and adjoining dunes at Kenfig NNR. Marsh Fritillary can still be found in boggy fields and old colliery sites near Nelson, Bargoed, Trethomas, Tonyrefail, Aberdare and Hirwaun, all in Glamorgan. And of course there is the Cross Hands, Carmarthen, site , which is an area of boggy fields managed by Butterfly conservation. God knows we have enough rainfall in Wales to keep us supplied with boggy fields. All we need to do is stop people from building on them, and then complaining when their houses suffer from rising damp ! It has always surprised me that this fritillary is found in 2 very different types of habitat; boggy fields and chalk downland.

Ah well, I`m just pleased if they all survive, somewhere, and brighten our spring and summer.

Blwyddyn Newydd Dda (Happy New Year) to all those who view this site and contribute to butterfly conservation.

Just to back Jenks up, I too have seen High Brown, Marsh and Dark Green in woodland within the principality of Wales.

The High Browns at Alun Valley emanate from a heavily wooded dip which, if it were to be chpped down, would doubtless lead to the loss of this spectacular species.

Similarly, the strong Marsh Fritillary colony at Aberbargoed grasslands is heavily dependent on the woodland cover that this site provides, whilst Kenfig Dunes, whilst certainly not a true woodland site, certainly includes patches of medium tree cover which Dark Greens seem to appreciate.

[Lee Hurrell]

Admittedly just a singleton, but Mark Senior and I saw a Dark Green Fritillary at Southwater Woods in early July last year.

We saw Neil that day too and he seemed a bit surprised.

Cheers

Lee

[Jack Harrison]

Lee:

... saw Neil that day too and he seemed a bit surprised.

That naughty Neil wasn't casting nasturtiums at your identification was he?

Jack

[Lee Hurrell]

No I don't think so Jack, I just got the impression he hadn't seen one there that's all!

Cheers

Lee

[Jack Harrison]

Lee:

No I don't think so Jack, I just got the impression he hadn't seen one [Dark Green Fritillary] there, that's all!

Well done Lee in getting one up on Neil.

I last saw a woodland DGF circa 1977/78 in Gloucestershire. But even then, they weren't particularly numerous in woods being far more abundant on the Cotswolds open hillsides. Today I get my annual DGF fix on chalk downs (eg Chilterns) or Norfolk coastal dunes.

Jack

[Liz Goodyear]

Ok second attempt - the first attempt which took about 30minutes to type disappeared (the third time this has happened to me) so since I thought I wrote something sensible for a change I am having a second attempt!

Not sure whether this all totally relevent to Jack's original post but here goes.

Lets start with Purple Emperors. Purple Emperors do not just restrict themselves to woodland sallow - If salix/sallow is in the landscape they will also be seen in the landscape whether it is a female looking for suitable egg laying habitat or a male emerging or also searching. In Hertfordshire/Middlesex we have had in the last 10 years or so several sightings from along the Grand Union Canal corridor/M25 gravel pits. They are utilising landscape sallows and well away from the territorial areas we are aware of (The canal at Tring is a good example).

In Hertfordshire we no longer have woodland/wood edge colonies of Grizzled Skipper - although there were historic colonies including a strong one in Broxbourne Woods.

I remember listening to a very interesting presentation at the Southampton International symposium by one of the European contributors. It was based on research surrounding the woodland ground temperatures and the effects it was having on the successful breeding of fritillaries. At around the same time there was a paper discussing Nitrate Deposition and the effects it was having on grassland habitats. In Hertfordshire we suffer the negative effect of ND - the paper explained the effect it was having on fertilising our grassland, encouraging rank grass which was out competing the fine grasses. At the same time we were also suffering a drastic decline in Small Heath.

So where does this lead, Jack comments that several species have migrated from woodlands, certainly Grizzled Skipper has in Hertfordshire, we don't have the rare Fritillaries.

So we have nitrate deposition which encourages rank grass, we have bad woodland management with ever narrowing rides, high canopy or closed canopy and a supposed warmer climate. We have wet summers intermingled with hot summers, but whilst the grass is ever growing, becoming ranker or cut without raking the actual ground temperature becomes cooler/danker. All factors that don't encourage the fritillaries to breed especially the ones where the caterpillars love to bask on hot ground/bracken. Therefore if the conditions outside the wood are more favourable is this not a reason for some species to change their habitat requirements. Certainly for Grizzled Skipper - the conditions in Broxbourne Woods deteriorated in the glades where it had found its home, there was no adjacent railway line to act as a conduit and the colony disappeared almost overnight.

One wonders how damp and cold the woodland floor can be even on a hot summers day - no doubt fritillaries are very aware.

Liz

[Lee Hurrell]

I last saw a woodland DGF circa 1977/78 in Gloucestershire. But even then, they weren't particularly numerous in woods being far more abundant on the Cotswolds open hillsides. Today I get my annual DGF fix on chalk downs (eg Chilterns) or Norfolk coastal dunes.

Jack, I've just remembered Juniper Bottom just through from Box Hill in Surrey. Prime DGF action there in the scrubby woodland edges. However, I do see more on the Sussex downs though then anywhere else.

Ok second attempt - the first attempt which took about 30minutes to type disappeared (the third time this has happened to me) so since I thought I wrote something sensible for a change I am having a second attempt!

Liz, it's happened to me in the past - if posting a long reply, sometimes I'll draft in Word and paste in, or copy what I've just typed on the site before hitting submit - of course leaving you with a paste up your sleeve!

Cheers

Lee

[Neil Hulme]

Hi Liz,
That frustrating problem happened to me several times in my earlier days of contributing to UKB! Sometimes, while writing a lengthy response or comment (particularly if having a tea or TV break), I would find myself automatically 'logged out' - losing everything. The same (loss of text) has also occasionally occurred when I've hit the 'submit' button at the precise moment someone else has posted to that thread. So now, for longer posts, I either write in Word then cut and paste, or make sure I've copied the text before hitting 'submit'. It only needs to happen a couple of times and an hour has evaporated .

Hi Jack/Lee,
I never doubted that Lee had seen a DGF at Southwater. As Lee suggested, I was simply surprised he'd seen one there (I never have). But 2010 has been notable for high butterfly dispersal rates, both for a number of usually more sedentary species, and those that habitually tend to wander. DGF had an excellent year in Sussex, turning up in areas where it has not been seen for years - including woodland sites. I saw them myself in Plashett Wood near Lewes. Individuals were also seen a long distance inland (bucking recent trends), even turning up near Burgess Hill.

Going back to Jack's original point, although there are of course plenty of exceptions (as pointed out by others), there has been a gross shift away from woodlands by some species. As commented on by Liz, the broadly changed (for the worse) structure of our woodlands (largely through dereliction in management terms) has been a main culprit. We all know about the nosedive performed by the most sensitive woodland species (e.g. PBF), but others such as Grizzled Skipper (a close woodland bedfellow of PBF) have also suffered, shifting their overall population towards unimproved grassland, brownfield etc sites. The lack of a patchwork of open, warm areas within woodlands has seen others 'leg it' too, including my beloved Duke of Burgundy.

The situation is different for Purple Emperor, which being an essentially arboreal species (and happy to lay eggs on partially/very shaded sallows), does not require these large, warm areas of open woodland floor. So it's still there and will remain so, but it does seem to be spreading outwards over the wider landscape. They've probably always ranged over more open ground where sallow abounds, but I suspect that this species (along with others) is now demonstrating wider habitat associations and tolerances, probably in response to climate change (often behaving more like their counterparts in mainland Europe). I don't believe for a moment that an army of Victorian naturalists and collectors could have missed them all along the crest of the West Sussex Downs, breeding at nearly 750' amsl; but they've always occurred 'up here' in mainland Europe.

Neil

[Liz Goodyear]

Diverting from Jack's post - yes on another forum I contribute, there are regular groans from contributors who lose their posts so there if doing a diary type entry, it has originated in a word document for that reason. Just haven't got the hang of this one yet - the previous two posts that went awol were short ones but sent later in "the evening." This last one caught me out - and I had taken time to write it as well!

Liz

[Matsukaze]

Black Hairstreak, which is increasingly being found in hedgerow colonies, may be another example of a species expanding its habitat preferences (or is it responding to changes in hedgerow management?)

The Boloria fritillaries and Wood White are other examples of species becoming eliminated from woodland, I expect for the reasons outlined by Liz, and being found predominately in what were once secondary habitats. Interestingly in Ireland the PBF and Wood White sinapis are both confined to scrubby slopes on the Burren, but presumably must have been more widespread at some point - perhaps the shortage of woodland in general, and ancient woodland in particular, in Ireland has caused this.

[Jack Harrison]

Matsukaze:

...and Wood White are other examples of species becoming eliminated from woodland...

Certainly not the case in Botany Bay/Tugley Wood in May and again in August last year when Wood Whites were in excellent numbers. I haven't been to Wicken Wood to the west of Milton Keynes for a couple of years, but certainly Wood Whites were doing well enough there last time I visited.

I wouldn't be surprised if the Wood White situation parallels that of the Purple Emperor in that non-woodland habitats are increasingly used in addition to the traditional woodland haunts. I believe that Wood Whites have a much broader range of habitats in mainland Europe. (Padfield?) My only experience of the species abroad was in Spain many years ago where I found them to be a widespread and common and seemingly not restricted to woods.

Jack

[Padfield]

You are right, Jack - wood whites are a common sight dithering abstractedly around quite open meadows in much of Europe. The problem is, most of the time we don't know if they're reali or sinapis. Evidence is emerging that these have subtly different habitat preferences but the data is thin on the ground as firm identification is only possible by dissection.

Guy

[Jack Harrison]

There have been suggestions that the south Dorset coast Wood Whites might be realii. However, I am told that examination of specimens has shown them all to be sinapis. So certainly sinapis in England is not confined to woods although inland it does have a preference for woodland.

In this respect, Wood White habitat requirements are broadly similar to Silver Washed Fritillary. SWF is usually (certainly inland) thought of as a woodland butterfly in England, but does occur in more open habitats in the southwest, particularly near the coast.

Jack

[Julian]

Very interesting topic...not wanting to steer to far off track about woodlands, but to divert out onto heathland for a minute and quote Liz...

there was a paper discussing Nitrate Deposition and the effects it was having on grassland habitats. In Hertfordshire we suffer the negative effect of ND - the paper explained the effect it was having on fertilising our grassland, encouraging rank grass which was out competing the fine grasses. At the same time we were also suffering a drastic decline in Small Heath.

We are increasingly seeing coarse grasses emerging on our local heathland and acid grassland here, to the detriment it would seem of our grass feeders, not just Small Heath but also Grayling and Wall Brown although the Wall Brown eats other more common grasses which might be considered coarse grasses. Certainly the fine grasses and fescues are disappearing from the tracks (paths of desire) through the heath, with coarse grasses taking over in their place and continued walking is compacting the tracks through the woodland as well. Most of the nitrogen deposition on one particular heath here in Suffolk seems to come from dogs. One particular heath I have in mind is also Ipswich's last Silver-studded Blue heathland - Purdis Heath - and therefore very valuable. It is an SSSI. SSB numbers have plummeted there (max count 4 seen last year) so we are tackling a very difficult situation. Of course the SSB problem also pertains to something else, ants or lack of them and scrub encroachment, but soil encrustation and compaction is also a major problem in the areas which are otherwise suitable, ie, open areas with short heather and devoid of scrub. We need to keep the dog walkers on board because they also love these areas but it can be a difficult subject to approach. Here is a link to those that are interested. You can read the pdf at the bottom of the page and Purdis Heath, page 9 and 28 references soil compaction: http://www.suffolkbutterflies.org.uk/co ... survey2009

Moving off the heath and back under the woodland canopy, Suffolk was once renowned for its woodland butterflies, particularly the fritillaries. It did seem very strange that they disappeared (post war and 1950's) when the violets upon which they fed were still in relative abundance. I guess it shows that nature is far more complex at times than we think. I think the loss was put down to geographical isolation of colonies caused by 'development' for housing and farmland, agricultural spray drift and who knows what else. Fortunately, last year saw an expansion (which seems to be the result of natural spread ) of Silver Washed Fritillaries back into several Suffolk and Norfolk Woodlands. One would hope that they carry within, some genetic propensity to do well in these areas, where those that went before died out albeit if they are living in more isolated situations. Perhaps this wanderlust which has been alluded to earlier in the thread is indeed part of the picture and a function of the genetic thick end of the wedge.

Julian