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Bryophyte survey of the Allt Lice, Choire nam Muc, Ardgour

A report for Adrian Laycock Ltd

by

N.G. Hodgetts

February 2017 Bryophyte survey of the Allt Lice, Choire nam Muc, Ardgour

N.G. Hodgetts

Introduction The Allt Lice and Choire nam Muc, Ardgour, is the location for a proposed hydro scheme (Fig. 1). The site, which drains from the hills around Choire nam Muc and runs into the River Gour above Loch nan Gabhar, and then into Loch Linnhe at Sallachan , has a more or less southerly aspect. The altitude is from ca. 10 m at the proposed powerhouse, rising to ca. 220 m at the proposed reservoir. The geology is a mixture of sandstone, quartzite and metamorphic rocks. The site lies within the Highland Council area, and Watsonian vice-county 97 (Westerness). It is within the Moidart and Ardgour Special Protection Area (SPA) but not within or close to any Site of Special Scientific Interest (SSSI) or Special Area of Conservation ( SAC).

The burn is rather open, with a series of waterfalls and cascades coming down the large slabby rocks. It becomes more incised further upstream, where there is a series of not very deep but steep-sided rocky gorges. There are few trees, but there are scattered small birch Betula pubescens, alder Alnus glutinosa and holly Ilex aquifolium. The surrounding vegetation is mostly typical species- poor western Scottish wet heath dominated by heather Calluna vulgaris and purple moor-grass Molinia caerulea, with bog myrtle Myrica gale common it wetter areas. There are also patches of bracken Pteridium aquilinum and drier areas with grasses. In the areas proposed for the reservoir, the burn is not at all incised, with smaller and more unstable rocks, and there are large patches of soft rush Juncus effusus.

Potential hydro sites are often potentially rich bryophyte ( and liverwort) sites. The western Scottish Highlands are of global importance for bryophytes. The temperate, wet climate is ideal for many oceanic species that are globally very rare and restricted climatically to areas with a high rainfall and only moderate temperature fluctuations. Their importance was first recognised by Ratcliffe (1968), who coined the term ‘Atlantic bryophytes’. The document Guidance for applicants on supporting information requirements for hydropower applications (SEPA 2009) recognises the necessity for a full bryophyte survey of potentially rich hydro sites so that green energy production can go ahead without damaging ’s natural heritage. The potential impacts of small hydroelectric schemes on bryophytes and were considered by Demars & Britton (2011).

Averis et al. (2012) have produced a scheme for assessing the bryological importance or potential importance of ravines for bryophytes, and making recommendations in relation to small hydroelectric schemes. This uses 29 species of nationally uncommon humidity- demanding bryophytes to classify sites to one of five levels of bryological importance. Unsurveyed or partly surveyed sites are also assessed using maps and aerial photographs. This work assessed 5629 water courses in western Scotland for their bryological interest. The majority of these have not yet been surveyed, but many have potential for high bryophyte interest. At least 136 sites have so far been

2 identified that are of such bryological significance that hydroelectric development could have an impact of national importance.

According to the National Biodiversity Network Gateway ( www.nbn.org.uk), this site has not been surveyed previously for bryophytes. Although bryologists have recorded in the area, there is no evidence of this site ever having been visited.

Figure 1. 1:25, 000 map showing location of proposed hydro scheme at Allt Lice and Choire nam Muc.

Methods Fieldwork was carried out on 7 February 2017. The site was walked, sampling close to the burn and the proposed pipeline route, and a bryophyte list was made on a standard Biological Records Centre RP35 card, with further notes made where appropriate. Specimens were collected where necessary for later microscopic examination. The survey was limited to the burn itself and rocks, banks and trees in the immediate vicinity of the burn and proposed pipeline route, and to the proposed area of the reservoir. The water level was high and the burn in spate at the time of the survey, but it was possible to access a sufficient portion of the burn for a reasonable view of the bryophyte flora to be ascertained; however, some stretches were inaccessible. Some digital photographs were taken in the field. Bryophyte nomenclature follows the British and Irish bryophyte checklist (Hill et al. 2008). Frequency of species is shown on the DAFOR scale. Oceanic, or ‘Atlantic’, species, according to the definitions of Hill et al. (2007), and ‘Western British’ species, as defined by Ratcliffe (1968), are highlighted. The site was also given a score according to the guidelines for the selection of Sites of Special Scientific Interest (Hodgetts 1992).

3 Nationally Rare and Nationally Scarce species are listed according to the updated lists by Pescott (2016).

Results A total of 100 bryophyte species were recorded ( Table 1, Fig. 2). Rocks in the burn itself are slabby and often scoured bare, or colonised by algae. Where bryophytes are present, the most common species in the water, or just above it, are aciculare, Sciuro-hypnum plumosum, Blindia acuta and Marsupella emarginata. Tops of boulders in and adjacent to the burn have spp. Racomitrium spp. and Andreaea spp. Grimmia ramondii is frequent or even abundant in places, G. funalis is locally frequent in patches along the length of the burn, while the Nationally Scarce G. muehlenbeckii is rare. There is some indication that some of these rocks are mildly base-rich, with Schistidium apocarpum also occurring occasionally. The soft peaty banks at the side of the burn are mainly species-poor, with a few common calcifuge species occurring underneath grassy tussocks, including Hyocomium armoricum, Pellia epiphylla and Cephalozia bicuspidata. Steep or vertical rock faces and crevices are mostly colonised by Diplophyllum albicans and algae. Mildly base-rich seepage is rare, but where it occurs there are Ctenidium molluscum and a few other common calcicoles.

This predominantly calcifuge bryophyte flora is similar throughout the length of the burn, but there are some points with more variety. A boulder-top at NM9673.6415 has Pterogonium gracile, growing with Grimmia ramondii. The Scottish endemic and Nationally Scarce moss Bryum dixonii was found at several points along the burn, growing in crevices in the slabby rocks above water-level (NM9673. 6398, NM9645. 6479. NM9669. 6437, NM9669. 6433). There is a concentration of bryological interest in the gorge at around NM9645. 6479, where it is relatively sheltered, with Herbertus aduncus ssp. hutchinsiae, Anastrepta orcadensis, Campylopus setiformis Nationally Scarce), Dicranodontium uncinatum ( Nationally Scarce), Plagiochila punctata, Hypnum callichroum, Hylocomiastrum umbratum and Ulota hutchinsiae growing on rocks and wet ledges. There is also Leptoscyphus cuneifolius on birch.

The area proposed for the reservoir is of little real interest, consisting mainly of dull wet heath and bog, and is very species- poor, with some large hummocks of Racomitrium lanuginosum and common species of Sphagnum. However, there is some indication that there is limited base-rich flushing, with stands of the Nationally Scarce Sphagnum affine occasional, and Campylopus fragilis unusually growing on some organic detritus in this area. There is an area of boulder scree towards the north-east part of the proposed reservoir, dominated by common calcifuge species. Large slabby rocks at the proposed dam have particularly large stands of Grimmia funalis.

The pipeline route runs through more dull wet heath that is of very little interest. There are a few patches of the Nationally Scarce Sphagnum strictum locally (e.g. NM9663.6460), but most of the route is dominated by purple moor -grass with a rather sparse bryophyte layer dominated by common species of Sphagnum, Racomitrium lanuginosum and Pleurozia purpurea. Patches of bracken are more common on drier

4 ground further downhill. The area of the proposed powerhouse is of no additional interest, being occupied by soft rush and small alder trees, with bryophytes sparse.

Figure 2. Allt Lice and Choire nam Muc, showing key features of bryological interest.

Table 1. Bryophyte species recorded from Allt Lice and Choire nam Muc Frequency on DAFOR scale: d = dominant, a = abundant, f =frequent, o = occasional, r rare. The qualifier ‘ l’ (‘locally’) is also used where appropriate.

Species Habitat Frequency Oceanicity Status Liverworts Anastrepta orcadensis Damp heathy banks o - Least Concern Calypogeia muelleriana Bare peat o - Least Concern Cephalozia bicuspidata Banks f - Least Concern Diplophyllum albicans Banks, rocks & epiphytic a - Least Concern Douinia ovata Rocks r Oceanic temperate Least Concern Frullania dilatata Epiphytic r - Least Concern Frullania fragilifolia Rocks o Western British Least Concern Frullania tamarisci Rocks & epiphytic f - Least Concern Gymnomitrion Rocks la Oceanic boreal- Least Concern crenulatum montane

5 Gymnomitrion obtusum Rocks o/ lf - Least Concern Herbertus aduncus Damp heathy banks o/ lf Oceanic boreal- Least Concern subsp. hutchinsiae montane Leptoscyphus cuneifolius Epiphytic on birch r Hyperoceanic Least Concern southern- temperate Lophocolea bidentata Wet ground r - Least Concern Lophozia ventricosa Banks r - Least Concern Marsupella emarginata Wet rocks a - Least Concern Metzgeria furcata Epiphytic r - Least Concern Mylia taylorii Damp heathy banks r Western British Least Concern Nardia scalaris Bare ground f - Least Concern Pellia epiphylla Damp shaded rocks & f - Least Concern banks Plagiochila punctata Epiphytic & rocks r Hyperoceanic Least Concern southern- temperate Pleurozia purpurea Wet heath & banks f/ la Oceanic boreal- Least Concern montane Scapania gracilis Rocks & epiphytic o/ lf Hyperoceanic Least Concern southern- temperate Scapania irrigua Bare ground r - Least Concern Scapania undulata Wet rocks f - Least Concern

Mosses Amphidium mougeotii Rock crevices r - Least Concern Andreaea alpina Rocks o Oceanic boreal- Least Concern montane Andreaea rothii Rocks f - Least Concern Andreaea rupestris Rocks f - Least Concern Anoectangium aestivum Rock crevices r - Least Concern Anomobryum julaceum Wet rocks o - Least Concern Blindia acuta Wet rocks f - Least Concern Breutelia chrysocoma Wet heath & banks f Hyperoceanic Least Concern temperate Bryum dixonii Crevices in slabby rocks in o - Nationally burn Scarce; Scottish endemic Campylopus atrovirens Wet heath & wet rocks a Hyperoceanic Least Concern temperate Campylopus flexuosus Peaty ground o - Least Concern Campylopus fragilis Decaying vegetation on r - Least Concern wet ground Campylopus pyriformis Peaty ground & dead o - Least Concern wood Campylopus setifolius Shaded banks r Hyperoceanic Nationally temperate Scarce Ceratodon purpureus Decaying vegetation on r - Least Concern wet ground Ctenidium molluscum Seepage in bank r - Least Concern Dicranella heteromalla Banks o - Least Concern Dicranodontium Shaded banks among r/ lf - Nationally uncinatum rocks Scarce Dicranum majus Banks o - Least Concern Dicranum scoparium Banks, rocks & epiphytic f - Least Concern

6 Entosthodon attenuatus Wet vertical peaty r Oceanic Least Concern surfaces Mediterranean- Atlantic Fissidens dubius Rock crevices r - Least Concern Grimmia funalis Top of rocks o/ lf - Least Concern Grimmia muehlenbeckii Rocks r - Nationally Scarce Grimmia ramondii Top of rocks f/ la - Least Concern Hedwigia stellata Rocks o - Least Concern Hylocomiastrum Banks r Western British Least Concern umbratum Hylocomium splendens Banks & wet heath a - Least Concern Hyocomium armoricum Wet rocks & banks f/ la Oceanic temperate Least Concern Hypnum andoi Rocks & epiphytic o/ lf - Least Concern Hypnum callichroum Banks r Western British Least Concern Hypnum cupressiforme Rocks r - Least Concern Hypnum jutlandicum Wet heath & banks a - Least Concern Isothecium myosuroides Epiphytic r - Least Concern Leucobryum glaucum Wet heath & banks o - Least Concern Loeskeobryum Banks r - Least Concern brevirostre Palustriella falcata Seepage in bank r - Least Concern Pleurozium schreberi Wet heath, rocks & banks f - Least Concern Pogonatum aloides Bare ground o/ lf - Least Concern Pogonatum urnigerum Bare ground & rocks o - Least Concern Pohlia nutans Decaying vegetation on o - Least Concern wet ground Polytrichastrum alpinum Rock crevices r - Least Concern Polytrichum commune Wet ground a - Least Concern Polytrichum piliferum Rock crevices o - Least Concern Pseudoscleropodium Damp grassland o - Least Concern purum Pterogonium gracile Top of rock r - Least Concern Racomitrium aciculare Rocks, mainly in burn a - Least Concern Racomitrium aquaticum Wet rocks r - Least Concern Racomitrium ellipticum Rocks f Oceanic boreal- Least Concern montane Racomitrium fasciculare Rocks a - Least Concern Racomitrium Rocks f - Least Concern heterostichum Racomitrium Rocks, banks & wet heath a - Least Concern lanuginosum Rhytidiadelphus loreus Rocks, banks & wet heath f - Least Concern Rhytidiadelphus Damp grassland o - Least Concern squarrosus Schistidium apocarpum Rocks o - Least Concern Sciuro- hypnum Rocks f - Least Concern plumosum Sphagnum affine Wet ground r/ lf - Nationally Scarce Sphagnum capillifolium Wet heath o - Least Concern subsp. rubellum Sphagnum compactum Wet heath f - Least Concern Sphagnum cuspidatum Acid flushes f - Least Concern

7 Sphagnum denticulatum Acid flushes & wet rocks r - Least Concern Sphagnum fallax Wet rocks o/ lf - Least Concern Sphagnum girgensohnii Banks o - Least Concern Sphagnum inundatum Wet ground o - Least Concern Sphagnum papillosum Wet heath lf - Least Concern Sphagnum Damp heathy banks r Western British Least Concern quinquefarium Sphagnum strictum Wet heath r Hyperoceanic Nationally temperate Scarce Sphagnum subnitens Wet ground r - Least Concern Sphagnum tenellum Wet heath o - Least Concern Thuidium delicatulum Wet ground o Western British Least Concern Thuidium tamariscinum Banks, rocks, etc a - Least Concern Trichostomum Rock crevices o - Least Concern brachydontium Trichostomum Rock crevices r Western British Least Concern tenuirostre ( including Oxystegus daldinianus) Ulota bruchii Epiphytic r - Least Concern Ulota hutchinsiae Rocks r Western British Least Concern Ulota phyllantha Epiphytic r Oceanic boreal- Least Concern temperate

Figure 3. Allt Lice & Choire nam Muc: lower part of burn, looking upstream from NM967639.

8 Figure 4. Allt Lice & Choire nam Muc: position of lowermost stand of Bryum dixonii, NM9673. 6398.

Figure 5. Allt Lice & Choire nam Muc: Bryum dixonii.

9 Figure 6. Allt Lice & Choire nam Muc: Pterogonium gracile and Grimmia ramondii on boulder- top at NM9673. 6415.

Figure 7. Allt Lice & Choire nam Muc: waterfall and holly, looking upstream just above NM9673. 6415: Grimmia funalis locally frequent here.

10 Figure 8. Allt Lice & Choire nam Muc: looking upstream into bryologically rich gorge, ca. NM965648.

Figure 9. Allt Lice & Choire nam Muc: Dicranodontium uncinatum in rich part of gorge, NM9645. 6479.

11 Figure 10. Allt Lice & Choire nam Muc: Campylopus setifolius in rich part of gorge, NM9645. 6479.

Figure 11. Allt Lice & Choire nam Muc: Herbertus aduncus subsp. hutchinsiae in rich part of gorge, NM9645. 6479.

12 Figure 12. Allt Lice & Choire nam Muc: Looking upstream over proposed dam area.

Figure 13. Allt Lice & Choire nam Muc: cushions of Grimmia funalis on slabby rock at proposed dam.

13 Figure 14. Allt Lice & Choire nam Muc: Looking upstream over lower part of proposed reservoir.

Figure 15. Allt Lice & Choire nam Muc: Looking upstream over upper part of proposed reservoir.

14 Figure 16. Allt Lice & Choire nam Muc: Sphagnum strictum on wet heathy bank at NM9663. 6460.

Conclusions This site is mostly rather dull and species- poor, with mainly calcifuge species and communities that are widespread in western Scotland. However, there are some points of interest, with several restricted oceanic (Atlantic) and species, and one Scottish endemic. No specially protected, Red List (Hodgetts 2011) or Nationally Rare Pescott 2016) species were recorded, but five Nationally Scarce ( Pescott 2016) were found:

Bryum dixonii: found at several points along the burn, growing in crevices in the slabby rocks above water- level ( NM9673. 6398, NM9645. 6479. NM9669. 6437, NM9669. 6433). This species is unusual in that it is endemic to Scotland ( i.e. occurring nowhere else in the world). It is known from about thirty sites altogether, so any site supporting this species is of some conservation significance .

Campylopus setifolius: recorded in damp vegetation on rock ledges in the gorge at NM9645. 6479. Patchily distributed in the Hebrides and western Highlands, with a few outlying records in the Southern Uplands, the Lake District and North Wales. This species also occurs in western Ireland, but is very nearly endemic to the British Isles and globally rare, the only other record being from northern Spain in 1934.

Dicranodontium uncinatum: several stands in damp vegetation on ledges in the gorge at around NM9645. 6479. This suboceanic boreal- montane species that has two habitats in the UK: Atlantic ravines and montane heath.

Grimmia muehlenbeckii: found on a boulder in the burn at NM9673. 6398. This species has been recognised as a British species only recently ( Porley & Maier 2007) and is probably widely overlooked. New county record.

15 Sphagnum affine: stands in mildly flushed wet ground in the proposed inundation zone of the reservoir. Although not a common , this Sphagnum sometimes turns up in mildly minerotrophic flushes by burns in the Highlands. It is likely to be overlooked, as it resembles the common S. palustre and S. papillosum. Further details of its distribution and ecology are given in Blockeel et al. (2014).

Sixteen oceanic or hyperoceanic (= Atlantic) species were recorded:

Liverworts Douinia ovata Gymnomitrion crenulatum Herbertus aduncus subsp. hutchinsiae Leptoscyphus cuneifolius Plagiochila punctata Pleurozia purpurea Scapania gracilis

Mosses Andreaea alpina Breutelia chrysocoma Campylopus atrovirens Campylopus setifolius Entosthodon attenuatus Hyocomium armoricum Racomitrium ellipticum Sphagnum strictum Ulota phyllantha

One of the 29 ‘target species’ listed by Averis et al. (2012) was found – the Nationally Scarce Campylopus setifolius, giving the site a score of 3 points. This means that it can be placed into Category C:

The site has a score of between 0 and 5 points, and the survey of the watercourse area was sufficiently thorough that it seems unlikely that further survey will produce enough additional records of uncommon hygrophilous species to raise the site score to 6 or more points. No further survey should be necessary in relation to a proposed hydroelectric scheme. With a score of <6 points the site is of low to medium bryological importance and hydroelectric development is unlikely to have a significant national/ international impact on humidity- demanding oceanic bryophyte assemblages. However, the following points should be noted for a hydroelectric scheme at a site in this category: ( 1) the bryophyte flora may be of local importance, for example including a species that is rare locally or is at the edge of its geographical range; (2) the watercourse may be important for other groups such as invertebrates; 3) the ecological acceptability of a proposed scheme might be reduced if many other watercourses in the local area already have hydroelectric schemes (i.e. few unmodified watercourses left in the area concerned).” ( Averis et al. 2012.)

Using the guidelines for the selection of Sites of Special Scientific Interest (Hodgetts 1992), the Allt Lice and Choire nam Muc scores 340, exceeding the 300 point threshold’ suggested for notification. This is, however, largely due to the presence of five Nationally Scarce species, none of which is particularly rare or threatened in the context of the western Scottish Highlands, as can be seen from the Atlas (Blockeel et

16 al. 2014). Of these five species, only Campylopus setifolius has been identified as a key plant of ravines likely to be affected by water abstraction ( Averis et al. 2012). It is possible that B. dixonii could be affected, as it does seem to be fairly narrowly restricted to intermittently irrigated habitats, but this is very uncertain according to our present state of knowledge. The stands of Sphagnum affine (and stands of Grimmia funalis on rocks at the proposed dam site) will obviously disappear if the reservoir goes ahead.

While this site has some interest, it is likely that all the species found occur elsewhere in this area. If the proposed scheme goes ahead, the usual mitigation measures can be recommended: large rock exposures and boulders should not be disturbed if possible. The pipeline corridor and disturbance from access tracks should be minimised as much as possible.

Acknowledgements Thanks are due to Adrian Laycock for letting and managing this contract, and to Shaun Corrigan for liaison during fieldwork.

References Averis, A.B.G., Genney, D.R., Hodgetts, N.G., Rothero, G.P. & Bainbridge, I.P. 2012. Bryological assessment for hydroelectric schemes in the west Highlands – 2nd edition. Scottish Natural Heritage Commissioned Report No. 449b. (available online at www.snh.org.uk/ pdfs/ publications/ commissioned_ reports/ 449b.pdf )

Blockeel, T.L., Bosanquet, S.D.S., Hill, M.O. & Preston, C.D. (eds.) 2014. Atlas of British and Irish bryophytes. Volume 2. Newbury, Pisces Publications.

Demars, B.O.L. & Britton, A. 2011. Assessing the impacts of small scale hydroelectric schemes on rare bryophytes and lichens. Scottish Natural Heritage and Macaulay Land Use Institute Funded Report. Scottish Natural Heritage Commissioned Report No. 421.

Hill, M.O., Blackstock, T.H., Long, D.G. & Rothero, G.P. 2008. A checklist and census catalogue of British and Irish bryophytes updated 2008. Middlewich, British Bryological Society.

Hill, M.O., Preston, C.D., Bosanquet, S.D.S. & Roy, D.B. 2007. BRYOATT. Attributes of British and Irish mosses, liverworts and hornworts. Abbots Ripton, NERC Centre for Ecology and Hydrology & Countryside Council for Wales.

Hodgetts, N.G. 1992. Guidelines for selection of biological SSSIs: non-vascular . Peterborough, Joint Nature Conservation Committee.

Hodgetts, N.G. 2011. A revised Red List of bryophytes in Britain. Field Bryology 103: 40- 49.

17 Pescott, O. 2016. Revised lists of nationally rare and scarce bryophytes for Britain. Field Bryology 115: 22-30.

Porley, R.D. & Maier, E. 2007. Grimmia muehlenbeckii Schimp. in Britain and Ireland. Journal of Bryology 29: 188-193.

Ratcliffe, D.A. 1968. An ecological account of Atlantic bryophytes in the British Isles. New Phytologist 67: 365–439.

SEPA 2009. Guidance for applicants on supporting information requirements for hydropower applications The Water Environment (Controlled Activities) (Scotland) Regulations 2005 (CAR). Aberdeen, Scottish Environment Protection Agency.

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