Surveying and recording the Harvestman Platybunus pinetorum
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For those who find Harvestmen (Opiliones) an interesting field of study, the past few years have been something of a bonus, or maybe that should be 'bunus' in view of the subject? Within the past ten years, the UK has seen four new species of Harvestmen reach these shores.

The four include Leiobunum sp.A (Schönhofer & Hillen 2008, Toss 2009, Wijnhoven et al. 2007) from a Worksop garden in 2009, Platybunus pinetorum (C.L.Koch, 1839) from a Sheffield garden in 2010, Scotolemon doriae (Pavesi, 1878) from a Plymouth cemetery in December 2017 (Bilton, 2018a) and Leiobunum limbatum (L.Koch, 1861) from Colne, Lancashire in 2019.

As is well known and publicised across this website, Dilys and I had recorded Leiobunum sp.A new to the UK, from the wall of a Worksop house back in 2009.

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So after Paul Richards found Platybunus pinetorum in his own garden in Sheffield, Yorkshire and then a few years later started to turn up at other sites around the UK, we definitely had another species to look out for in Nottinghamshire.

The first record of Platybunus pinetorum for VC56 Nottinghamshire

Holborn Hill Plantation is a superb area of mature Beech woodland situated about half a mile east of Meden Vale. In Nottinghamshire, decent sized areas of Beech woodland is difficult to come by and soon to become even rarer. Unfortunately Holborn Hill Plantation and the adjacent Hangar Hill Plantation are both marked up for felling, probably to take place late in 2021 or early 2022. I decided to have a wander up there on May 16th 2020, at the time thinking it would be worth just going and bringing back some leaf litter to sort through later.

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Parking the car at Gleadthorpe, I began walking towards Holborn Hill Plantation, occasionally stopping to photograph the odd insect as a reminder that I'd seen it. Its a preferred practice of mine, as it just saves taking a notebook out.

I then cut off the main track heading towards the plantation, but slowed to have a casual glance for anything sat sunning itself on the low foliage. As I walked I spotted a Harvestman sat on a Hogweed leaf in typical Platybunus triangularis fashion and to be honest that is exactly what I thought it was. But on close approach, I could see the distinct chestnut-coloured occularium, easily noticeable even from a metre away. Then noticing the generally darker colouration of this specimen, I knew that I had accidentally stumbled on the county's first Platybunus pinetorum.

Refound in 2021 and survey results

On March 21st 2021 and with the weather being fairly mild, I made a first visit of the year to Gleadthorpe and Holborn Hill Plantation areas, in the thin hope of finding P. pinetorum. The search proved unsuccessful, but a return to the area on March 30th was met with almost immediate success, finding a specimen about two feet up the trunk of a Beech and no more than 50 metres away from the location of the original record. 

I next visited on April 17th, with conditions pleasantly warmer and seemingly ideal. Surprisingly, the individual present on my last visit was still on the same tree and further searching revealed two more specimens on other Beech trunks nearby. All three P. pinetorum were recorded resting between two and four feet from ground level.

During a follow-up visit to the site on May 4th, I initially found just the one specimen, which was the individual first found on March 30th. It was still on its favoured Beech and had now moulted to adult. There was no sign of the other two individuals found on my previous visit to the site, but conditions were windy where they had been located and I presumed too exposed and cold this time.

So I decided to try another area close by, which (especially today) was considerably more sheltered. Within a minute or so, I'd found a single specimen and then four more and all on the same Sycamore. Once again, all five were situated between three and five feet from ground level. Additionally, there was another individual on a Sycamore little more than five metres away. A total of seven P. pinetorum was more than I'd ever expected on a single day.

 
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May 7th and I returned to Holborn Hill Plantation for yet another survey. This purpose this time, was to check which individuals (if any) were still present from May 4th and to survey the area much more extensively. In view of the future tree-felling on this site, I wanted to start and determine its range locally.
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  I walked south along the tarmac track and away from the area of the 2020 record (showed as the red dot in the above satellite image) and within a few minutes found my first P. pinetorum of the day. This already meant that I'd already extended the range on site, so now it was a case of by how much it could be extended. Another specimen was found five feet up a Beech trunk at the top of Holborn Hill Plantation, so I continued to follow the edge of the woodland till I reached Hangar Hill Plantation.

By this time it had become increasingly windy, due to a nearby passing shower and conditions weren't as good as they had been a few minutes earlier. But some twenty metres into Hangar Hill Plantation and I'd found another, which was moving round to find a more sheltered side of the trunk it was on.

I found no more until I reached the southerly edge of Hangar Hill Plantation, and was very surprised to find three more individuals in quick succession, one of which was found feeding on the leaf mining moth Phyllonorycter maestingella. These were the last I found, although I continued to search eastwards to the edge of Budby South Forest.
 
With a lack of smooth barked trees to easily check, surveying was more difficult and much slower, but the targets set out at the start of surveying were more than reached during the visit. There's obviously a healthy population of Platybunus pinetorum here, but it's already under threat through loss of habitat via felling and timber extraction, with extraction being the most destructive part of the process. Should as many P. pinetorum be located to somewhere safe? Its a tempting proposition, but the big problem in Nottinghamshire, is finding anywhere that's safe for release
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On May 14th I went further afield, although not setting out with the proviso of looking for Platybunus pinetorum. However, the decision was quickly determined as being a good one.

I drove a couple of miles north up the A614 and decided to look at a narrow roadside plantation of Beech, Sweet Chestnut and Pine, as it was an area we had never looked at before. I was met with immediate success and within half an hour, had recorded a staggering 104 adult and near adult P. pinetorum. This was very much a minimum count, as I didn't cover the whole area and just stopped counting, as now I wanted to try other locations nearby, to determine the range here locally.

All individuals as seen before, were recorded on the trunks of trees at heights between one and eight feet (just one) from ground level. Several trees had counts of five individuals and certainly three to a tree was common. I recorded very few trees without any P. pinetorum on it. As has always been the case so far, all those found have been well distanced from each other, usually well over a foot apart. Only once have I seen two individuals within touching distance and they certainly don't group in the way most Leiobunum often do.

 
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Site   Grid Ref   Year   Notes
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Gleadthorpe   SK597700   2020 and 2021   One on 16/05/20 and one present from 30/03/21 to 04/05/22
Holborn Hill Plantation   SK597698   2021   Two on 17/04/21
Holborn Hill Plantation   SK597693   2021   One at this location on 07/05/21
Hanger Hill Drive   SK598697   2021   One on 07/05/21
Hangar Hill Plantation   SK594691   2021   One on 07/05/21
Hangar Hill Plantation   SK597687   2021   Three at this grid ref on 07/05/21
Clumber Park   SK648752   2021   Count of 104 on May 14/05/21
Appleyhead Wood   SK647776   2021   Five on 14/05/21
Ollerton   SK652686   2021   28 recorded on 16/05/21
Clumber Park   SK638776   2021   One recorded on 16/05/21
Mansfield Woodhouse   SK565655   2021   Four on16/05/21
Rufford CP   SK641647   2021   Two at different locations just off the A614 on 18/05/21
Vexation Lane   SK642655   2021   One recorded on 18/05/21
Sherwood Forest   SK605686   2021   Three on 23/05/21 and one in the same area on 11/06/21
Sherwood Forest   SK603685   2021   One on 11/06/21
Thynghowe   SK600684   2021   One recorded on 11/06/21
  Leaving this location, I drove north for another mile or so and stopped to try suitable looking habitat at Appleyhead Wood, close to the A614 and A1 junction and across the road from the entrance to Clumber Park.

After a couple of minutes searching, I'd located a single P. pinetorum about seven feet up a Beech, then went on to find a further four more. This site does hold some very old Beech with wide girths, but none were found to hold any P. pinetorum.

Two days later on May 16th, I surveyed a private area of Thoresby Estate woodland containing some Beech, Pine and Sycamore, which is adjacent to a large and frequently used layby.
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This site also lies on the A614, but is situated close to a large traffic island at Ollerton and is a few miles south of the Clumber sites surveyed previously. Platybunus pinetorum was again found to be present here, with a total of 28 counted.

A couple of other locations in the area were surveyed, including Boughton Brake which lies about half a mile east of the A614. No P. pinetorum were found, so I headed north up the A614 and turned left on to the A57 towards Worksop. The A57 marks the northern boundary of Clumber Park and a small strip of Sweet Chestnut woodland looked promising and eventually paid off with a single P. pinetorum despite a great deal of searching. After returning home, I made a check on two local woodland sites which seemed potentially suitable. To my surprise, four more P. pinetorum were found in Beech woodland on the A6075 Peafield Lane near Market Warsop, making this a discovery in another completely new area.
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  May 17th and 18th. So after finding P. pinetorum well away from it's recently discovered Clumber sites, the aim now was to try and determine the extent of its range. With the Peafield Lane site being something of a local dumping area (in general line with most of the county's laybys) was the county's road system a key actor in helping P. pinetorum colonise Nottinghamshire, or had it been here at very low population levels all along and remained undetected?

Only the former Nottinghamshire county recorder for Arachnids - Howard Williams, Dilys and myself, had done any recent Opilione recording in the county and invertebrate surveys conducted over the past 20 and 30 years had never recorded it, although no surveys had been carried out at the sites P. pinetorum has since been recorded from. So is it highly likely that it has gone undetected over the years?

In Nottinghamshire, that must be considered as doubtful, as through mapping the distribution of Psychidae moths in the county, we'd spent many hours in the field (and at all of the sites on the above map) over the past 13 years, looking at tree trunks for larval cases of Psychidae moths and recording Harvestmen and other invertebrates at the same time. Certainly we'd never seen it before.
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But if it is as recent an arrival into the UK as records seem to suggest it is, then the speed of range increase is great. Nottinghamshire's woodland records seem quite unique, as virtually all other UK records of P. pinetorum are casual records from urban or suburban locations. But then again, is anyone making any attempt to check woodland sites in their county? It seems not and that may be because recorders deem it as being a waste of time, perhaps on the basis of the largely singular, urban nature of most county's records.

So it was decided to check sites along the A614 closer to Nottingham, but suitable habitat at Gravelly Hollow near Calverton (containing Sycamore) and a small plantation of Beech on Longdale Lane near Papplewick, both proved negative. However, I eventually met with success at Rufford CP further north on the A614 and after a while searching mixed woodland at the site of the road, I finally found a single P. pinetorum at the entrance barriers. Now Rufford is less than a mile from the Ollerton site where I recorded P. pinetorum a day or so before, so it was not unexpected here. I then found an additional specimen a hundred yards away on a signpost and when I cross over the A614, I soon found it to be present at on a Sycamore at Vexation Lane.

On May 23rd I tried a small area of Beech woodland lying just on the edge of the Sherwood Forest NNR, at the south-west corner of Budby South Forest and the north-west corner of the Sherwood Forest CP. Once again, most of these trees are marked for felling (presumably later in 2021) and includes some mature Beech and some younger trees. Three P. pinetorum were found in total, so another site for this most handsome and beautifully marked Harvestman.
Two small groups of mature Beech covering just a few square metres within Seymour Grove (a belt of mostly Scot's Pine separating Budby South Forest from Sherwood Forest CP) were also checked.

There were no further surveys until June 11th when I again returned to the Budby South Forest area. One female was soon found at SK605686, where three were found on my previous visit. Continuing on, I located another female about a hundred yards or so slightly further west and finally found another on Beech next to Thynghowe at Hangar Hill Plantation.
 
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Platybunus pinetorum - A Harvestman new to Nottinghamshire
Harvestmen in Nottinghamshire
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