Holt Heath, East Dorset, Sunday, 23rd March 2014
A meeting held to explore one of the better conserved Dorset heaths and record its lichen assemblage. Wet met at 10.30 23rd, March 2014 by the NNR sign on Holt Heath on the south side of the road from Three Legged Cross to Holt around 1km west of the Cross Keys pub at SU0517 0455.
Brian Edwards lead, with Neil Sanderson doing Cladonia (or his head in), with Jenny Seawright, Brian Gale, Malcom Storry, Ginny Copsey, Pat Fry, Mathew Prince and Nichola Bacciu attending. Neil’s dog Ollie came along for the walk. The warm spring weather of the previous weekend had been replaced by more typical early spring weather of sunshine and heavy showers, fortunately there were not too many of the latter. In the morning we started by doing a circuit around the heath from the car park west towards Lower Row to a gravel pit, then back east to wetter heath about Bull Barrow and back to the car park.
1Km Grid Square SU0504
To the north of the road the heath started off with a dense Heather canopy with lichens rare (SU050046), and only only two species seen: Cladonia portentosa and a KC + purple-red Pixy Cup with course granules, presumably most likely Cladonia merochlorophaea rather than Cladonia cryptochlorophaea.
1Km Grid Square SU0404
Passing into the next 1km grid square where there was an area of heath with a much more open and uneven canopy, and a richer lichen assemblage (SU049 047). This looked like the site of an old burn, emphasising the importance of fires in producing suitable habitat for diverse heathland lichen assemblages. This included a small amount of the K – and UV + blue white chemical form of Cladonia squamosa var. squamosa and more of the K + yellow and UV – Cladonia squamosa var. subsquamosa. This is minor chemical variation but there appears to be unnamed morphological variation that cuts across these named chemical varieties. The typical form, found on trees and less acid shaded habitats has small to non-existent cups hardly exceeding the width of the podetia, with pale interiors exposed inside the small pierced cup, with abundant peeling squamules formed from the pale white cortex on the podetia. Both chemical forms occur as this morphological form but in typical morph the K + UV – form is usually dominant. In acid heaths a highly distinctive form occurs, with wide flaring cups unto twice the width of the podetia, with shiny chestnut to black interiors and the podia with few squamules peeling from the pale grey cortex. Both chemical occur as this morphological form too but Cladonia squamosa var. subsquamosa is usually dominant. Here the small amount of Cladonia squamosa var. squamosa was the typical morphological form but the Cladonia squamosa var. subsquamosa was the heathland morph. These morphological forms are ecologically distinct, but genetic work is required to determine if they are taxonomically distinct. Also seen was a small patch of an unusual form of Cladonia portentosa, this has a grey white, rather than yellow-white cortex and brown tips to the podetia branches. It was Pd – and with UV + bright blue-white bases to the podetia, demonstrating this was Cladonia portentosa, but was a rare form lacking, or with low levels, of usnic acid. This is named Cladonia portentosa f. subimpexa, but appears to be of limited significance.
Rich old burn SU049 047:
Cladonia portentosa
Cladonia merochlorophaea
Cladonia humilis on old dung
Cladonia squamosa var. squamosa typical form
Cladonia macilenta
Cladonia floerkeana
Cladonia ramulosa
Cladonia furcata subsp. furcata
Cladonia crispata var. cetrariiformis
Cladonia squamosa var. subsquamosa heathland form
Cladonia ciliata var. ciliata
Cladonia portentosa f. subimpexa
Cladonia coccifera s. lat.
Cladonia portentosa f. subimpexa & Cladonia squamosa var subsquamosa, heathland type.
Dorset Nature shows the typical form of Cladonia squamosa in the top three pictures
We also recorded the Gorse in this area. As seems typical it supported an assemblage of quite nutrient demanding lichens; possibly reflecting the nitrogen fixing properties of the shrub rather than high nitrogen deposition.
Gorse lichens SU049 047:
Ramalina fastigiata
Ramalina farinacea
Fuscidea lightfootii
Punctelia jeckeri
Evernia prunastri
Melanelixia subaurifera
Xanthoria candelaria s. lat.
We then reached our first target, an old gravel pit at Waypoint HO01 (SU04944 04795). Such disturbance features are usually a good place to look for lichen diversity on heathland and this was no exception. Straightaway I found, patches of sterile Cladonia callosa Nb (NS) on the pit floor and the banks, new to Dorset. This was one of the recent exciting finds made during the New Forest Heathland Lichen Survey. Until 2011, this Atlantic European endemic was unknown from lowland England but was recorded only from peaty banks in the uplands in the UK. However, it also has internationally important populations in the Netherlands, so it was not to surprising to find it on the New Forest. What was surprising was how widespread it proved to be. It had been recorded in 54 1km grid squares by the end of 2014, mainly occurring in disturbed locations in hollow ways and pits. It has also been recorded sparingly in Berkshire and Essex in post industrial sites as well as heathlands. This was very much an expected find for the Dorset Heaths but a good start to the meeting. It has been overlooked as it is often sterile and even when it has podia, these are tiny. It is actually quite easy to identify once known; the squamules have a brown topside with bright white undersides and are are Pd – and exceptionally bright UV blue-grey (grayanic acid). The only similar material is sterile Cladonia crispata, this is also Pd – and UV +, but fluoresces a less bright white (squamatic acid). The key difference, however, is that the undersides of Cladonia callosa are tomentose and those of Cladonia crispata are smooth. The UV difference is marked however, once learned; on overcast days Cladonia callosa can be found by scanning likely banks with a UV lamp!
Cladonia callosa
(more pictures Dorset Nature)
Other species in the pit included Placynthiella dasaea Nb (NS), a sorediate version of the commoner isidiate Placynthiella icmalea, which was new to the Dorest heaths, but is very under recorded. The Pixie Cups on the bank, were probably Cladonia chlorophaea s. str., with coarse granular soredia and granules mixed with squamules along with a white medulla that is little exposed. On heaths it is actually rather scarce and confined to less acid grassy banks in disturbed locations. On more acid heathland habitats, it is entirely replaced by members of the Cladonia grayi group, with finer soredia at least higher on the cup and much medulla typically exposed, which is often tinged pinkish-brown.
Also spotted in the pit bottom were some bumbling Lesser Bloody Nosed Beetles.
Lichens in pit:
Cladonia callosa
Cladonia coniocraea
Rhizocarpon reductum fint
Baeomyces rufus
Placynthiella dasaea
Placynthiella icmalea
Peltigera didactyla
Cladonia floerkeana
Cladonia chlorophaea s. str.
Micarea viridileprosa
Porpidia crustulata fint
Psilolechia lucida Heather stem & terr
Cetraria muricata
Cladonia cervicornis subsp. cervicornis
In the gravel pit
Bryan then lead us east east towards a wet heath with relic lichen interest by Bull Barrow. On the way there, more rich humid heath occurred just east of the gravel pit (SU049 407) with Cladonia ciliata var. ciliata and Cladonia uncialis subsp. biuncialis.
1Km Grid Square SU0504
Back into SU0504, we descended into lower lying wet heath south of Bull Barrow. Much of this was old with a dense heather canopy and lacked much lower plant cover and had no lichens at all. Along a path, however, a few species turned up where past trampling and left some open ground including Micarea lignaria var. lignaria a typical species of the transition from humid to wet heaths in the New Forest .
SU054 048 path wet heath
Cladonia merochlorophaea
Cladonia portentosa
Baeomyces rufus
Micarea lignaria var. lignaria
Rhizocarpon reductum
Cladonia coccifera s. lat.
Porpidia crustulata fint
As we reached the area of relic richer open wet heath that Bryan had been looking for at (SU0560 0482) we endured sharp fierce rain storm. The wet heath was in poor shape, but we did find single thalli each of the specialist lichensPycnothelia papillaria (picture Dorset Nature) and Cladonia strepsilis. This decline, however, is typical of older stands of this type of vegetation and it would certain recover if subjected to a cool heath fire.
SU0560 0482
Pycnothelia papillaria 1 plant
Cladonia portentosa
Cladonia uncialis subsp. biuncialis
Cladonia crispata var. cetrariiformis
Cladonia strepsilis 1 plant
Cladonia ciliata var. ciliata & the rain storm
We then headed south along a track to words the road, adding Cladonia humilis on the road bank at SU056 047. By the road at Cocks’ Moor Pond some Sallow scrub was recorded, this had a fairly standard assemblage of common species, but provided an opportunity to demonstrate the difference between Hypotrachyna afrorevoluta and Hypotrachyna revoluta s. str. (see). One interesting lichen seen was fertile Lecanora barkmaniana Nb (NS), an under recorded, and nearly always sterile, lichen of nutrient enriched bark.
SU056 046 Sallow:
Candelariella reflexa
Fuscidea lightfootii
Hypotrachyna afrorevoluta
Hypotrachyna revoluta s. str.
Parmelia sulcata
Flavoparmelia soredians
Punctelia subrudecta s. str.
Punctelia jeckeri
Parmotrema perlatum
Flavoparmelia caperata
Lecanora barkmaniana fr
Physcia tenella
Evernia prunastri
Melanelixia glabratula
Usnea cornuta
Ramalina farinacea
Lecanora chlarotera
Violella furcata (was Mycoblastus furcata)
Phlyctis argena
Xanthoria parietina
On Frangula alnus
Dimerella pineti
We then headed back along the road to the cars for lunch in the sunshine.
Lecanora barkmaniana & Hypotrachyna revoluta s. str.
(more pictures Dorset Nature)
1Km Grid Square SU0604
After lunch we drove the cars 1.5km east to a pull in at SU0670 0495 by Summerlug Hill. From here we walked south and worked along the eastern edge of the valley bog where the drier areas of wet heath and the transition to humid heath were locally very lichen rich in patches of open canopy heath. We started recording in SU066 048, finding a good range of heathland lichens. At Waymark HO02 (SU0662 0484) there were large patches of a distinctive heathtail Cladonia, the podetia occasionally forked and largely finely sorediate, but typically with corticate bases. This was K –, Pd + orange and had strong UV + white fluorescence from the undersides of the squamules and exposed medulla; Cladonia rei NT (NR). The curious curving to one side of the podetia here is not a feature of the species and was mirrored by other Cladonia podetia here. This is a local but under recorded species, which was growing with Cladonia macilenta, Cladonia floerkeana, Cladonia diversa and Cladonia merochlorophaea (KC + red-purple course granular podetia)
SU066 048 in wet heath/humid heath transition:
Cladonia portentosa
Cladonia crispata var. cetrariiformis
Cladonia squamosa var. subsquamosa heathland form
Cladonia floerkeana
Cladonia cryptochlorophaea (KC + red-purple fine granular podetia)
Cladonia rei
Cladonia macilenta
Cladonia diversa
Cladonia merochlorophaea (KC + red-purple course granular podetia)
Cladonia uncialis subsp. biuncialis
Cladonia ciliata var. ciliata
Hypogymnia physodes
Cladonia rei
Continuing into SU066047, we found our first Cladonia strepsilis patch at Summerlug at Way Point HO03 (SU0668 0479), along with well developed Cladonia verticillata material. This species has been much misinterpreted in Britain; it is not identified by the multiple tiers of podia proliferating from the centre, Cladonia cervicornis s. str. can also do this, although the tiers are usually shorter and less elegant in the latter species. The species are actually distinguished by the basal podetia. In Cladonia verticillata they are simple squamules with only shallow indented edges, while Cladonia cervicornis s. str. has deeply dissected squamules.
Working along the side of the mire to the sound of a Curlew calling we found more locally frequent Cladonia strepsilis at Waymark HO04 (SU06720 0479) and then at Waymark HO05 (SU0673 0472) I found a very odd Cladonia. This was growing on mounds on humus projecting above the wet heath, probably old broken down tussocks. This had small basal squamules densely crusted with soredia on the underside, with short contorted sorediate podetia just projecting out of the squamules. In large patches, the podetia and squamules were grey, with brown apothecia or pycnidia, but other thalli were yellowish-green, with red apothecia. Both types had bright blue-white UV fluorescence. The yellowish-green, with red apothecia material was obviously Cladonia incrassata Nb (NS) and it seemed that the grey material with brown apothecia was also this but was a rare and unusual chemotype without usnic acid in the thallus and lacking rhodocladonic acid in the apothecia. It obviously still had squamatic acid because of the UV fluorescence. The LGBI mentions a very rare chemotype with squamatic, didymic and thamnolic acids, but this should be K + yellow and Pd + yellow, which our usnic acid free material was not. This may be another new chemotype but this will need TLC to determine.
SU066047 in wet heath/humid heath transition:
Cladonia strepsilis
Cladonia verticillata
Micarea prasina s. lat. on Calluna
Cladonia squamosa var. subsquamosa
Cladonia incrassata
Cladonia ramulosa
Cladonia strepsilis, Cladonia verticillata compared with Cladonia cervicornis s. str. & Cladonia incrassata.
Dorset Nature includes pictures of Cladonia incrassata podetia with brown and red appothecia
Carrying on south east into SU067046, produced more Cladonia strepsilis at Waypoint HO06 (SU06767 04688). In SU068046 there was more Cladonia incrassata, at Waypoint HO07 (SU06801 04665), this time all typical thalli with yellow-green thallus and red apothecia. At Waypoint HO08 (SU0682 0465), there was more Cladonia rei NT (NR) and Cladonia strepsilis with Cladonia coccifera s. str. Nb (NS); having larger bullate squamules inside the cup than the Cladonia diversa material seen earlier. In the bog a dead pine and a live birch were examined, with more Cladonia strepsilis on the Bog edge (Waypoint HO09, SU 06890 04640).
SU066046 in wet heath/humid heath transition:
Cladonia strepsilis
SU068046 in wet heath/humid heath transition:
Cladonia incrassata
Cladonia coccifera s. str.
Cladonia rei
Cladonia strepsilis
Cladonia macilenta
Cladonia floerkeana
Xanthoria polycarpa LP
Amandinea punctata LP
Cladonia coniocraea LP
Lecanora confusa Bt
Cladonia macilenta with Cladonia floerkeana
Having worked a fair way down the western edge of the bog through superb lichen rich low productivity wet heath, we turned north to walk around the lower slopes of Summerlug Hill through dense well grown drier heath. This lacked any lichens and the small area of turf stripping was too young to have any either. An Oak added Arthonia punctiformis, Lecidella elaeochroma f. elaeochroma and Arthonia radiata to the days list and pine lignum Trapeliopsis flexuosa. Back at where we started, we then quickly trawled west through the open wet heath along the edge of the bog, noting species of particular interest only. We found in succession; Cladonia strepsilis (Waypoint HO10, SU0650 0475), more Cladonia strepsilis (Waypoint HO11, SU0651 0469) and Cladonia incrassata with red and brown apothecia (Waypoint HO12 SU0650 0467).
Then I made the find of the meeting; a small piece of Cladonia zopfii (Waymark HO13, SU0642 0471) in open wet heath, new to Dorset and first modern record outside of the New Forest for England. Malcolm then found a much bigger and more impressive thallus. This species looks superficially very similar to Cladonia uncialis subsp. biuncialis, but is not actually closely related and once learned is quite distinct. There are subtle differences in the branching pattern (Cladonia zopfii has branches divergent at a wider angle and the tips narrowing to longer tapering point). The key difference, however, is that the cortex of Cladonia zopfii is thicker and less transparent and the clumps of algae within the cortex are not easily visible (they can be seen if a light is shone through the podetia). This gives the podetia a silvery grey look, very like Cladonia arbuscula. In Cladonia uncialis subsp. biuncialis the thiner cortex allows the algae clumps to be easily seen, giving the podetia a reticulate look close up and a yellow-green look from a distance. Close too, the mature thallus of Cladonia zopfii is also lumpy (the bumps are the algae clumps), while that of Cladonia uncialis is smooth. The final conformation, best seen at x40, but visible with care in the field, is that Cladonia uncialis subsp. biuncialis had a powdery surface to the hollow inside the podetia, while inside Cladonia zopfii this is fibrous.
Cladonia zopfii
More Pictures at Dorset Nature
In Britain Cladonia zopfii is often considered a northern species, because it was previously mainly known from the Highlands (BLS Map) but in a European context it is a lowland oceanic species. It has a curious history in southern England. The first specimen was collected in 1910 by H M Livens from near Bramshaw Wood, (collected as Cladonia uncialis, Det. B J Coppins) (Coppins, 1978). In the early 1980s I searched Black Bush Plain near Bramshaw Wood with Francis Rose with out success. In 2011, at the beginning of the New Forest Heathland Lichen Survey Brain remind me of this record and, sure enough, a few weeks latter on a Wessex Lichen Group meeting at the incredibly rich Ogdens (15 October 2011 Ogdens) I collected some odd Cladonia uncialis, which turned out to be Cladonia zopfii! Since then, Cladonia zopfii has turned out to be widespread in the New Forest and has been found in 37 1km grid squares. These include old gravel pits at Piper Wait, by Bramshaw Wood, which may be Livens’s 1910 location. I must have overlooked the species as Cladonia uncialis subsp. biuncialis quite a few times before 2011. In the Forest it is found in disturbed sites in drier heaths such as hollow ways and pits as well as in wet heath as at Holt Heath. A final titbit, Wilhelm Zopf (1846 – 1909) was a german professor who founded the study of the secondary chemistry of lichens and his name was commemorated by Vainio in his naming of Cladonia zopfii.
After the Cladonia zopfii record we wounded back to the cars, adding Placynthiella icmalea on ironstone to the list.
We had had a very successful meeting, finding to significant new records for Dorset; Cladonia callosa Nb (NS) and Cladonia zopfii Nb (NS) and other good records such as Cladonia rei NT (NR), a very rare usnic acid free form of Cladonia incrassata Nb (NS) and a strong population of the declining Cladonia strepsilis. We recorded a total of 64 taxa, of which 38 were recorded from the ground and stone (see species list). Of these one was a Near Threatened (and Nationally Rare) and five were Notable species (all Nationally Scarce). Using the Cetrelia, Cladonia & Pycnothelia Index (CCP Index: that is the total numbers of terrestrial Cetrelia, Cladonia & Pycnothelia taxa recorded, this is used to assessed heathland lichen diversity) the whole site scored 26, with the heath north of the road, where we looked at a variety of habitats scoring 20. The Summerlug site south of the road, where we recorded a single habitat, scored 17. This compares well with the New Forest, as measured by using the CCP score as 1km square totals, with the area we surveyed about equivalent to a systematically surveyed one km square on the New Forest. The Holt Heath score of 26, compared to the New Forest, is higher than average but not equivalent to the richest squares. It is especially encouraging that the some of the distinctive New Forest lichen assemblage has survived in Dorset. (See the New Forest Heathland Lichen Survey)
Holt Heath now has light grazing restored but appeared to lack any controlled burning. The results of the New Forest Lichen Survey are emphasising the importance of moderate to heavy grazing, controlled burning and or disturbance in various combinations to promoting lichen diversity. At Holt Heath, north of the road the area of highest diversity was an old quarry and the richest areas of heath were on the sites of old wild fires. The rarity of the highly sensitive and rapidly declining Pycnothelia papillaria at Holt Heath as a whole, was an indication that the current lichen assemblage is determined by past impacts that are not occurring at present on Holt Heath.
Reference
Coppins, B. J. (1978) H. M. Livens Lichen Collection at Bolton Museum; Notes on some Interesting Specimens. Naturalist 103: 105-107
To see the route taken click on the text below.
