Hampshire bryophytes

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Bryophytes in Hampshire and the Isle of Wight

Hampshire (VC11/12)

Hampshire is a large and diverse county with a wide variety of typical lowland habitats, including semi-natural woodland, chalk grassland, heathland, acid grassland, saltmarsh and coastal shingle. Some of these are reasonably rich in bryophytes, but the bryoflora of the county is greatly boosted by the New Forest, an extensive area of traditionally managed woodland and heathland in the south-west of the county (wholly within VC11). Hampshire's climate is relatively warm and dry, and the topography relatively flat, so is not well suited to support large numbers of species. Nevertheless, the county has recorded at least 494 recognisable taxa, made up of 121 liverworts, 3 hornworts and 370 mosses. Excluding subspecies and varieties, the total of about 487 species amounts to 46% of the British flora of 1069 species, as covered by the 2014 Atlas of British & Irish Bryophytes.

The internationally important acid bogs and calcareous mires of the New Forest are amongst the richest and best recorded bryophyte habitats in the county. Surprisingly, however, Hampshire as a whole has been very poorly recorded both in historical times and during the present day. Most of our bryological knowledge of South Hants (VC11) is based on the records of liverwort specialist Jean Paton, dating mainly from 1957-1960 when she was working at Southampton University. She also collated the records available at the time to produce the first flora for the vice-county, published in 1961. In VC12 most past recording work was carried out by E.C. Wallace, and later by Alan Crundwell in the 1980s. After a long gap the late Rod Stern undertook a more systematic survey of VC11 between 2000 and 2008, assisted by Francis Rose and Howard Matcham. Other contributions have come from people such as Neil Sanderson who has lived and worked in the New Forest for many years.

The bryophyte flora of the county was published in the Flora of Hampshire (1996), written by Crundwell and Rose. Stern published the Atlas of the bryophytes of South Hampshire in 2010, which mapped records on a 5 x 5km basis. His book also usefully includes a facsimile copy of Paton’s flora. A large body of data including herbarium records, Francis Rose's notebook records and some of the records from local meetings remain to be checked and input into the BBS database. Hampshire distribution maps have been compiled at 10km resolution here, but serve to illustrate the large gaps in recording (or data compilation) historically. They do not yet include records made after March 2016. A BBS national recording meeting was held in Hampshire in 1956, and the New Forest was also visited during the Dorset meetings held in 1930 and 1977. See the BBS web site for further details.

The New Forest supports many local and rare species at a county scale and nationally. Several species occur that are more at home in the wetter west and north of Britain, sometimes well outside their main British range. It supports the largest population of the British Red Data moss Zygodon forsteri, an epiphyte on old Beech trees. It also has significant populations in a Britain and Ireland context of several threatened/declining species, including the liverworts Pallavicinia lyellii and Fossombronia foveolata and the mosses Dicranum spurium and Hypnum imponens. Away from the Forest the most important habitat is the Chalk, on which there are at least three quite different communities, including one on warm, exposed substrates with Fissidens dubius, Weissia spp. and Abietinella abietina and another on cooler, higher altitude, often north-facing grassland, notable for the calcicole liverwort Scapania aspera and nicknamed the southern hepatic mat by Francis Rose.

Recent noteworthy discoveries have included a small but apparently thriving population of the Red Data liverwort Cephaloziella baumgartneri, a limestone-loving species, at Netley Abbey on the south coast; populations of the Mediterranean (and probable alien) liverwort Riccia crystallina on campsites in the New Forest; the nationally scarce ephemeral moss Bryum gemmilucens, also on a campsite in the New Forest and the predominantly western moss Pohlia bulbifera at Hogmoor Inclosure, a sandy heathland site in VC12.

Isle of Wight (VC10)

The Isle of Wight is relatively well recorded historically. National BBS meetings were held there in 1964 and 2002 (see BBS web site). The account of the bryoflora by the previous recorder, the late Lorna Snow, was published in the Isle of Wight Flora (2003). Provisional 5km distribution maps based on historical data are available here.

Bryologically, the Isle of Wight (or the Island as it is known locally) is moderately rich for its size, with 375 species and distinct taxa recorded (including several new species found in the last few years). Important bryophyte habitats include chalk grassland and bare chalk on the downs and in old quarries and the semi-natural and wet woodlands on both acid and calcareous soils. There is some dry heath at Headon Warren and a few scattered small bogs and fens, though the bryological interest may have declined at some of these due to lack of management. There are of course plentiful and varied coastal habitats, including dry calcareous cliffs and chines with wet seepages, and the landslips which provide areas of wet, calcareous mud when fresh. Recently, it has been discovered that Tennyson Down in the far west of the Island supports sizeable patches of liverwort-rich grassland with an affinity to the southern hepatic mat (see above).

The Isle of Wight has important populations of four national rarities, the liverworts Southbya nigrella and Cephaloziella baumgartneri, and the mosses Acaulon triqetrum and Philonotis marchica. The first three are all found at St Catherine’s Point; the last at Shanklin Chine and the adjacent coastal cliffs. In Britain Southbya nigrella only occurs elsewhere on the Isle of Portland, where it is widespread; Cephaloziella baumgartneri also from Portland and very scattered sites along the south coast eastwards, including the single locality in Hampshire as noted above. Acaulon triqetrum is a species of coastal cliffs with very few sites between Dorset and Sussex, where it has seriously declined. A huge population has been found recently at Culver Down in the south-east of the Island. Philonotis marchica has only been recorded from one other British site in Yorkshire, in 1903. Recent searches for it have discovered that Philonotis rigida, a related species, may in fact be the dominant of the two at Shanklin cliffs, though this needs to be fully confirmed. Another two nationally rare liverworts have been recorded from the vice-county historically: Cephaloziella turneri and Solenostoma caespiticium, the latter from the Wilderness in 1908, the first British record. Though undoubtedly long extinct at that site, this species could conceivably still occur on a coastal seepage somewhere.

The Isle of Wight is also famous for the moss Leptophascum leptophyllum, discovered in a stubble field on the 1964 BBS meeting and named after the Island as a species ‘new to science’, Tortula vectensis. It has since been found sporadically at sites on the Isles of Scilly, Lizard Point and Herefordshire, also typically in stubble fields or on footpaths. It is now realised to be widespread globally in warm temperate and subtropical regions but had been described under several different names. In Europe it is present throughout parts of the Mediterranean, extending north-east to Germany.

Another new species to the British bryophyte flora was discovered relatively recently on the Island. This was the European species Crossidium sqaumiferum, found by Welsh bryologist Sam Bosanquet during a family holiday on cliffs near St Catherine’s Point in June 2013.