Hazeley Heath, Sunday 17 August 2014

A joint meeting with the Hampshire Flora Group, to recored the RSPB's new heathland reserve at Hazeley Heath along with the more established nature reserve owned by Hart Distinct Council at the south east end of the heathland. We met at 10.30 am in the car park in the centre of Hartley Wintney at SU7669 5697. There was a good turn out of botanists, lichenologists and bryologists, some being mixtures of these. Tony Mundell, lead the vascular plant side, Neil Sanderson, the lichen recording and John Norton recorded bryophytes. Also attending were Peter Billinghurst, Sarah Ball, Eric Clement, Ginnie Copsie, Andy Cross, Brian Gale, Mike Marshall, John Polland, Mary and Trevor.

We got to the heath by walking through the housing estates, with the botanists stopping to examine Storksbills Erodium species on the pavement before we got to the common. The first part of the open land was through former fields and areas of the common dug for gravel and then used as a town dump before being capped, so we started of in nutrient enriched woodland, recording in SU7656. We recorded mainly common place species on White Poplar and Ash, with lichen assemblages indicative of high pH bark:

White Poplar (Pp), Ash (Ash) & Birch (Bt):
Amandinea punctata Pp
Arthonia radiata Pp
Candelariella reflexa Pp
Catillaria nigroclavata Pp
Lecania cyrtella Pp
Lecanora chlarotera Pp, Fx
Lecanora confusa Pp, Bt
Lecanora expallens Bt
Lecidella elaeochroma f. elaeochroma Pp, Fx
Leptorhaphis atomaria Pp
Melanelixia glabratula Pp
Opegrapha vulgata Fx
Parmelia sulcata Pp
Phaeophyscia orbicularis Pp
Physcia adscendens Pp
Punctelia jeckeri Pp
Punctelia subrudecta s. str. Pp
Xanthoria parietina Pp

I made a couple of collections from the White Poplar. The most surprising had some black perithecia, which I thought might be an Anisomeridium species but when I eventually got around to looking at the specimen they proved to be much more interesting. The perithecia were unto 0.25μm diameter and had curved needle shaped 1 septate spores of 25 - 28 x 2.5μm; this was Leptorhaphis atomaria, a poplar specialist. To date this has mainly been recorded from Aspen in eastern Scotland but its is a widespread species there and not confined to old woods. Recently it has been found on Aspen and Black Poplar in eastern England and has probably been overlooked in England. A black disk proved to be Catillaria nigroclavata as expected, a much under recorded species of high pH twigs.

On the the old common proper, along with the capped rubbish tip, there were wooded old untipped gravel pits which therefore had acid soil. These had been colonised by Oaks, which had a more acid tolerant lichen assemblage:

Acid Oaks (Q) & Oak twigs (tw):
Arthonia didyma Q tw
Cyrtidula quercus Q tw
Evernia prunastri Q tw (small)
Flavoparmelia caperata Q tw
Hypogymnia physodes Q tw
Lecanora expallens Q
Lepraria incana s. str. Q
Parmelia saxatilis Q tw
Pyrrhospora quernea Q
Ramalina farinacea Q tw

Oak twigs are a good substate to use judge ammonia deposition as they are naturally acid and will have their pH raised by high ammonia deposition. Here the twig assemblages was still composed of acid tolerant species, with Hypogymnia physodes, Flavoparmelia caperata and Parmelia saxatilis present but although the ammonia sensitive Evernia prunastri was also found, it was only small and stunted. The Air Pollution Information System (APIS) website gives the Ammonia Concentration for the general area as 1.09 µg m-3 link (a modelled 3 year average over 2010-2012). This level is just over the Critical Level of 1.0 µg m-3m for epiphytic lichens. Given the area we recorded was probably quite well buffered from local sources of pollution this seems about right.

On the open capped tip the path edges had some quite interesting vascular plants species, but crawling about only produced two lichens: Collema auriforme on soil and Verrucaria nigrescens on Brick. A small plant of Greater Burdock Arctium lapa was demonstrated by Tony Mundell, a vascular plant species as I had only seen once before.

From here we moved on down on to cleared former heath. Here a Plantlife project has tuft stripped an area of seepage step, this had regenerating bryophytes and vascular plants of interest, including the Bogmoss Sphagnum auriculatum and the Sundews Drosera intermedia and Drosera rotundifolia but was too wet for lichens. The bank above the seepage produced typical woodland/disturbed ground lichen species with Cladonia chlorophaea s. str., Cladonia fimbriata on moss on stumps and Cladonia coniocraea.

Turf striped seepages step

Back up on the plateau, a concrete road and structure produced some standard “concrete weeds”: Aspicilia contorta ssp. contorta, Caloplaca flavocitrina, Caloplaca oasis, Lecanora albescens, Lecanora campestris ssp. campestris, Lecanora dispersa, Lecanora muralis, Lecidella stigmatea and Verrucaria nigrescens.

Finally into the fenced grazed area we stopped for lunch, when the forecast midday rain proved to be a limited shower. By the lunch spot were some magnificent fruiting bodies of the fungi Pseudoboletus parasiticus parasitising earth balls.

Pseudoboletus parasiticus parasitising earth balls

The grazing is relatively recent, the heathland previously having been long abandoned and grazing was absent in 1995 when I did a lower plant survey of the south eastern end of the heath, which is owned by Hart District Council. Now down in the open bottom land there was a large area of well grazed heath. To the right of the track was some short grazed humid heath (NVC H2c), which would typically have produced high diversity in the New Forest in a long grazed heath, but in this recently restored area only produced Placynthiella icmalea and Cladonia humilis.

Grazed Heath

To the north of the access track productive herb rich wet heath (NVC M16b) dominated. This is a poor habitat for lichens, but a good one of bryophytes and vascular plants. At waypoint HH001 (SU76455 57838), I found a hummock of the Bogmoss Sphagnum molle, now a very rare species in the Thames Basin heaths. I had found it 300m to the north west in the same heath in 1995, but otherwise it is currently only known from Eelmoor Marsh in North Hampshire. Other typical species were the vascular plants Cirsium dissectum, Succisa pratensis, Eriophorum angustifolium, Narthecium ossifragum and Salix repens and the Bogmosses Sphagnum subnitens and Sphagnum rubellum.

Moving into the grid square SU7658, more base rich flushed areas within the M16b heath added the base demanding bryophytes Calliergonella cuspidata and Bryum pseudotriquetrum to John’s list. An Aspen left standing within the heath was recorded but was not rich in lichens: Lecanora carpinea, Lecanora chlarotera, Lecanora confusa, Lecidella elaeochroma f. elaeochroma, Melanelixia subaurifera, Physcia adscendens and Xanthoria parietina. Worked timber on a bridge over a ditch added Candelariella vitellina f. vitellina.

Finally to the north of the Hart District Council land, patches less productive humid heath supported small bare patches with the beginnings of a more interesting heathland lichen assemblage with Cladonia ramulosa, Cladonia floerkeana, Cladonia portentosa, Cladonia squamosa var. squamosa and Cladonia cryptochlorophaea. At waymark HH002 (SU 76416 58107) the rather local Cladonia glauca was found, which was new to the heathlands of north east Hampshire. Just over fence on to RSPB land the developing lichen heath continued in a heath regenerating after a fire with sterile Cladonia diversa, young Cladonia crispata var. cetrariiformis, Cladonia cryptochlorophaea and Cladonia portentosa.

The Hart District heaths produced 12 Cladonia taxa, double the number recorded in 1995, when even Cladonia portentosa was not found. The heaths were ungrazed in 1995 and lacked the open patches in short humid heath that have developed under grazing pressure. These short open patches look promising for a recovery of a reasonable heathland lichen assemblage in the future.

Moving on into the RSPB managed land, a mown verge added Peltigera hymenina as we route marched on to the next area of open heathland. Into SU7558, a root plate of a fallen Birch in the recent woodland at waymark HH003 (SU75889 58198) produced Psilolechia clavulifera, new to north Hampshire along with Psilolechia lucida, Cladonia chlorophaea s. str. and Cladonia coniocraea. The Psilolechia clavulifera is a widespread species in the uplands of shady banks, but appears to be an uncommon specialist of rootplates on fallen trees in woodlands in the lowlands.

Finally we reached the second area of heath, which is still ungrazed. This was mostly recently cleared of young Birch wood to restore the heath, but with patches of older relic heath. It consisted of dry heath on plateau, with the surface mostly pitted with old gravel diggings. Even the older looking areas were generally poor in lichens and only three Cladonia species were found on the ground. The species recorded were: Cladonia cryptochlorophaea, Cladonia rangiformis, Cladonia coniocraea, Cladonia chlorophaea s. str. on Scots Pine stumps and Peltigera didactyla in a bonfire site. To the south was some older short open humid heath, which looked more promising but proved to be dominated by exotic bryophyte species with the moss Campylopus introflexus abundant and the liverwort Lophocolea semiteres present at SU7557 5802. A couple of lichens were found in this heath Cladonia furcata ssp. furcata and Cladonia subulata. This area was disappointing, similar old gravel pits on heathland would have been very rich in the New Forest.

Left a bit early, and on the way back Andy and I passed some more impressive Greater Burdock Arctium lapa plants on the capped tip.

Greater Burdock Arctium lapa

To see the route taken click on the text below.

The habitats we surveyed, recent woodland and degraded heathland were not lichen rich and we only recorded a total of 59 lichen taxa, see Species List. Even so, these did include two new species to North Hampshire: Leptorhaphis atomaria and Psilolechia clavulifera. Both are certainly small under recorded species, but the latter does appear to be an uncommon ephemeral of shaded disturbed ground in the lowlands, specialising in rootplates of fallen trees. The Leptorhaphis atomaria is even more interesting, it has been widely recorded on Aspen in Eastern Scotland but this was only the third site recorded in England. Here it was found on White Poplar. Currently it is not clear if it is very under recorded in England or actually very rare. It is possible it is recolonising English poplar species as acidifying pollution declines.

The heathland was not rich, the south east (the seepage step and the grazed area) had 12 Cladonia species recorded growing on the ground with nine in the grazed area. The latter included Cladonia glauca, which was new to the north east Hampshire heaths. In the more degraded north east had only five taxa recorded. The south east area, however, showed a considerable improvement over a survey of the same area carried out by me in 1995, with double the numbers of Cladonia species found in 2014. Even the ubiquitous Cladonia portentosa was not found in 1995 but has now reappeared. Just as the lichen richness in the New Forest is promoted by a combination of grazing, controlled burning, management continuity and low ammonia deposition, the general poverty observed in the Thames basin heaths appears to be associated with a combination of lack of grazing, lack of controlled burning and or wild fire, management discontinuity and higher ammonia deposition. Which factors are most important is not clear but the reintroduction of grazing at Hazelely has clearly helped.