Studland Dunes, Dorset, Wednesday, 26th June 2013

A general ecological study of the Studland Dunes is being under taken by the National Trust, the Cyril Diver Project (Cyril Diver Project Facebook Site). For this Jenny Seawood and Paul Evans mapping the areas of lichen dominance and the aim of the WLG meeting was to record the lichen diversity of the dunes. The dune were already well known by Brian Edwards but new to me. The dunes have built up in an area of shallow sea since the 17th Century (see link). We started at 10.30, meeting at the National Trust car park near the South Haven ferry at SZ0352 8635.

Neil Sanderson and Brian Edwards were leading with, Jenny Seawood, Leslie and Michael Balfe and Paul Evans along with two dogs, Tawny and Ollie meeting at the car park, Vince Giavarini joined us latter after moth trapping the night before.

We walked down to the shore and then along the dunes to a newly formed dune slack cut off by very recently formed dunes and colonised by Allseed Radiola linoides, The dryer edge of the dunes had a few pioneer grassland lichens with Cladonia humilis, Peltigera hymenina and Cladonia scabriuscula noted (Radiola Dune Slack SZ0395 8604). We then reach the north end of the younger first dune ridge, which dates from the latter half of the 19th century, and stated recording at SZ039 859. The area was mainly dominated by species poor tall heather but more open areas supported a rich lichen flora with Cladonia furcata, Cladonia cervicornis s. str. Cladonia portentosa, Cladonia gracilis, Cladonia uncialis, Cladonia subulata, Micarea prasina s. lat. on Calluna stems, Cladonia floerkeana, Cladonia diversa, Cladonia squamosa var. subsquamosa and Cladonia grayi s. str. recorded. A more disturbed area of dune added Cetraria aculeata and Cladonia foliacea.

First ridge, at the start

Vince then caught us up and added a couple of epiphytes from Bog Mytrle Myrica gale on the wet ground west of the ridge: Mycoglaena myricae Nb (NS) and Arthonia punctiformis. At about SZ039 858 (about SZ08-01) we found a rich epiphytic assemblage on some old straggly Bell Heathers Erica cinerea but not others; why some bushes were of interest was not at all clear. The lichens included the mainly upland twig species Caloplaca asserigena Nb (NS), which is very rare in the lowlands, with only two known sites, here at Studland on heather twigs and in Suffolk on Shrubby Sea-blite Suaeda vera twigs in Saltmarsh (Chris Hitch, pers. com.). Other species on the Erica were Lecanora symmicta, Lecanora confusa, Flavoparmelia caperata, Melanelixia subaurifera, Fuscidea lightfootii, Hypogymnia physodes, Parmelia sulcata and Ramalina farinacea, while Calluna added Parmotrema perlatum. On the ground were Trapeliopsis granulosa, Cladonia portentosa, Cladonia uncialis, Cladonia cervicornis s. str., a monstrous form of Cladonia arbuscula and Hypogymnia physodes.

Caloplaca asserigena
Cladonia arbuscula

More Cladonia arbuscula was found at SZ0392 8580 along with Cladonia gracilis, Cladonia furcata, Cladonia foliacea, Cladonia ciliata var. ciliata, Cladonia ciliata var. tenuis and Cetraria muricata. I also collected what seemed like Cladonia rei (SZ08-01, SZ03925 85804), looking more twisted and curved than Cladonia subulata, without cups with antler like proliferations and a Pd + orange rather than orange-red reaction, but could not be sure as my UV light was not working well (it had begun to produce too much white light). Latter with a new light I confirmed the medulla was UV + white, and this was Cladonia rei NT (NR); new to Dorset.

The pattern of lichen interest in the first dunes was now clear, high lichen diversity was mainly found on old paths between very dense old Heather. The latter had Cladonia portentosa abundant locally but supported a low lichen diversity. The current high lichen diversity of the dunes was largely dependent on past heavy disturbance of the dunes by holiday makers. This disturbance appeared to have reduced in recent years, providing plenty of open bare ground for lichen colonisation. This mixture of diverse formerly eroded patches and species poor tall heather continued along the dune ridge and about SZ039 857 there was some fertile Cetraria aculeata, a rare occurrence.

First ridge habitat
First ridge lichens

At SZ037 854 the common Placynthiella icmalea was added to the list and further rich heather bushes were found (SZ08-02, SZ03787 85424), with Calluna producing Caloplaca asserigena Nb (NS) along with an odd form of Lecanora symmicta while Erica cinerea supported Jamesiella anastomosans. The odd form of Lecanora symmicta is a distinctive one with a cream-yellow thallus and blue-black disk and persistent thalline margins, while internally the epithecium is blue-green. Normal Lecanora symmicta has paler whiter thalli, thalli margin soon excluded, disks cream to pink, pale orange or brown and epithecium colourless or yellow-brown to olivaceous (from LGBI description). Curiously I had seen this taxa before, on heather stems and on chestnut paling snow fences, in low arctic wind blown heath in the Cairngorms, Scotland; it might actually be a good species and would worth investigating further. Near here Jenny picked up a white crust on a Calluna stem, which was clearly an Ochrolechia, and even my dying UV light showed some orange fluoresce, proving it to be Ochrolechia arborea NT (NR). This is a very rarely recorded species, which Jenny had found previously new to Dorset from the Studland Dunes; one to look out for elsewhere. Beyond this there was some Cladonia incrassata Nb (NS) on bank by path (SZ08-03, SZ 03791 85391) with Cladonia fimbriata on dead Marram Grass Ammophila arenaria. The final new species on this ridge were Cladonia ramulosa and Cladonia cryptochlorophaea (KC + fleeting red-purple).

Odd form of Lecanora symmicta

We had by now reached a crossing point over the boggy, tree invaded dune slack between the dune ridges, where we could reach the inland second dune ridge, so we stopped for lunch. During lunch a Hobby flew over.

After lunch we crossed over to the second ridge, which originated in the late 18th Century. Here the heath was very different; much shorter and more open. It looked rabbit grazed but there were no signs of rabbits, so its condition was a bit of a mystery. However it got like this, it was in very good condition for lichens, with a high cover and diversity. Walking west, the first species recorded were Cladonia portentosa, Cladonia uncialis, Cladonia furcata, Hypogymnia physodes, Placynthiella icmalea, Cladonia crispata, Trapeliopsis granulosa, Cladonia ramulosa, Cladonia ciliata var. tenuis, Cladonia diversa, Cladonia subulata and Cladonia cryptochlorophaea. At SZ80-04 (SZ03509 85296) I collected some more potential Cladonia rei NT (NR), which later confirmed. After this further additional species were Flavoparmelia caperata, Cladonia arbuscula, Cladonia ciliata var. ciliata, Cladonia gracilis, Cetraria muricata, Cladonia ramulosa and Cladonia cervicornis s. str. More Bell Heather Erica cinerea bushes with rich epiphytic assemblages were found with Evernia prunastri plus Hypogymnia physodes, Lecanora symmicta, Melanelixia subaurifera, Lecanora confusa and Hypotrachyna revoluta s.str.. Further fertile Cetraria aculeata was found and on and on another Erica cinerea, Parmotrema perlatum, Fuscidea lightfootii, Cladonia fimbriata and Hypogymnia tubulosa were added as heather epiphytes.

Second ridge habitat
Second ridge lichens

At SZ08-05 (SZ0342 8526) as well as Cladonia arbuscula and Cladonia ciliata var. ciliata there was some potential Cladonia coccifera s. str., with flattened granules in the cup (see Jenny's pictures); I have not fully got a grip of the differences between Cladonia diversa and Cladonia coccifera s. str., but material approaching the latter does occur in the lowlands. The simple assumption that all lowland material is Cladonia diversa probably not advisable.

We then turned back east along the edge of the mire developing in the former dune slack between the first and second ridges. Most of this is mesotrophic bog (poor fen) but Bryan pointed out a small patch of Sphagnum magellanicum, marking a small patch of developing oligotrophic valley bog. Peltigera didactyla was added from a bonfire site on the mire edge and then Bryan refound an orange-red Waxcap, Hygrocybe coccineocrenata, which was first named from here. It was growing on Sphagnum in mesotrophic bog with Sphagnum squarrosum and Marsh Cinquefoil Comarum palustre. If not over grown by Molinia due to the absence of grazing, the mires here would potentially include M5 mire (Carex rostrataSphagnum squarrosum mire), a very rare mire type in the lowlands. I picked up some Reindeer Moss which seemed to be both Pd – and UV – at SZ08-06 (SZ 03421 85226), this would have been very interesting if correct. It was, however, just my malfunctioning UV light; it was yet more of the extremely variable Cladonia portentosa with bright blue-white fluorescence on the lower cortex. Finally we found another patch of epiphyte rich heather at SZ08-06 (SZ0347 8525), with Graphis elegans on Calluna and more Caloplaca asserigena Nb (NS) on Erica cinerea along with Xanthoria parietina, Physcia tenella, Ramalina farinacea and Usnea cf flammea.

Cladonia portentosa

We recorded a total of 53 taxa from the heathland (see species list), with a CCP index (Cetraria/Cladonia/Pycnothelia index) score of 25, (high quality heathland lichens sites typically scoring over 15). Comparing the first and second dune ridges, we recorded 39 taxa with a CCP score of 20 on the first ridges and 35 taxa with a CCP score of 17 on the second ridge, with the latter a shorter survey. There were interesting differences between the two ridges; the younger ridge had a characteristic assemblage of costal heathland, also seen in disturbed inland sand as at Woolmer, in the Hampshire Weald. Cladonia foliacea was frequent, but absent from the second ridge and taxa such as Cladonia furcata ssp. furcata, Cladonia cervicornis s. str. and Cladonia ciliata var. tenuis much more prominent. On the second ridge, the assemblage was much more typical of heathland podzols with Cladonia coccifera s. lat. and Cladonia crispata var. cetrariiformis appearing. It was still noticeably less extreme than many New Forest heaths, with Cladonia furcata ssp. furcata and Cladonia cervicornis s. str. still present on the second ridge; these are typically absent from strongly podzolised soils, with Cladonia cervicornis s. str. replaced by Cladonia verticillata.

In terms of management, some for of disturbance and or grazing which produces open patches and short heather swards is essential if the lichen diversity of the Studland dunes is to be maintained.

Download the KMZ file to view route and waymarks in Google Earth, or view as picture by clicking on the text link link below.

The epiphytic assemblages on heathers, mainly Bell Heather Erica cinerea, are very interesting. The assemblage includes the mainly upland Nationally Scarce species Caloplaca asserigena, which appears to be a rare species of twigs of under shrubs in coastal location in the lowlands. Another rarely recorded species found was Ochrolechia arborea NT (NR), but this has been found in woods as well as on coastal heather. Other than this the assemblage is mainly composed of common twig species, including species indicative of high pH or nitrogen pollution, such as Physcia tenella, Ramalina farinacea and Xanthoria parietina. The patchiness of the occurrence of this assemblage on the site is in itself curious, why are some Bell Heather bushes rich and other barren? This community peaked my interest and I subsequently looked for similar assemblages in the New Forest; similar old straggly Bell Heather bushes are easy enough to find but they are mostly barren. With close looking I have found Micarea prasina (most probably Micarea micrococca) occasionally and rarely Fuscidea lightfootii and Jamesiella anastomosans, the latter two mainly on old Heather Calluna vulgaris. Subsequently, however, a very similar assemblage was found at Headon Warren in coastal heathland (14 September 2013 Headon Warren WLG). Interesting Caloplaca asserigena, has also be recorded in a similar rich assemblage on old Rockrose bushes on limestone in Öland, Sweden (Fröberg et al, 2009). This type of assemblage appears to be found on old under shrubs where the pH of the bark is not too low. To occur on heathers this type of assemblage probably requires a pH boost from salt spray.