Bazzania Bhutanica N.Kitag. & Grolle

Bazzania bhutanica N.Kitag. & Grolle Critically Endangered CR (B1,2c) ————————————————————————————————————————— Class: Marchantiales Order: Jungermanniales Family: Lepidoziaceae Description and Biology: Bazzania bhutanica is a very characteristic species. The species is pale olive-brown and faintly frosty, rather rigid, in thin, loosely interwoven mats; shoots prostrate, 1.2 - 2.0 mm wide; stems up to 20mm long, thick, subterete, often covered with thin mucilaginous substance. It shows such a long series of criteria which prevail in the subgenus Inaequilatera (1) plants small and growing prostrate in a thin, depressed mat; (2) leaves asymmetrically oblong-ovate to - lanceolate, deeply bilobed and very widely spreading in nearly a single plane; (3) their margins denticulate and crenulate from projecting cells; (4) underleaves mostly trilobed (but this is often obscured by large lateral teeth); (5) leaf cells various-sized and forming a vitta; (6) cell walls evenly thicknened and with indistinct trigones; (7) cuticle of leaf cells strongly asperous and often verruculose. Distribution and Habitat: Bazzania bhutanica is endemic to Himalaya and Bhutan where it is known from two localities (Long et al. 2010). The species grows on crumbling, shaded rock faces and vertical, gravelly, northwest-facing banks in subtropical rain forest and is only known from undisturbed habitats. History and Outlook: Prior to 2009, only one colony of Bazzania bhutanica was known from one locality (discovered in 1982). Over the past century intermittent logging has removed many of the trees at the original site and much of that forest is now secondary. Other impacts come from human activities like firewood and fodder harvesting, and cattle grazing, both of which are sustainable in moderation, but a significant threat to biodiversity if over-indulged. Dr David G Long, together with local experts, were able to visit Bhutan for 3 weeks in November/December 2009 and undertook field work to carry out a search for B. bhutanica. On 6 December 2009 they relocated the plant in the original locality at Buduni and also in a new locality nearby at Lafeti Khola, and were able to collect more detailed ecological data, reassess the threats and take digital images of the plant and its habitat. The two localities are ecologically almost identical, in stream valleys in degraded subtropical forest, with trees such as Castanopsis indica, Chisocheton cumingianus, Duabanga grandifora, Lithocarpus fenestratus, Litsea salicifolia, Pandanus furcatus and Tetrameles nudifora, shrubs including Boehmeria macrophylla, Callicarpa arborea, Hyptianthera stricta, Piper sp. and Wendlandia grandis, climbers such as Calamus latifolius, Glycosmis cymosa, Lepisanthes senegalensis, Mikania micrantha, Rhaphidophora hookeri and Pothos scandens, and the large ferns Angiopteris sp. and Cyathea spinulosa. The B. bhutanica plants formed yellow-green mats closely appressed to a vertical, gravelly, northwest-facing bank (an eroded ancient river terrace), in the Buduni ravine with about 50% cover in an area of approximately 5 x 1 m, closely associated with a Hymenophyllum species and many bryophytes. Both sites are highly vulnerable to immediate and future threats. Immediate threats are any increase in forest clearance by villagers for firewood and fodder for livestock, and over-grazing by cattle, both of which will cause further loss of tree and shrub cover, and therefore destroy the shade and humidity vital to the survival of B. bhutanica. Longer-term threats appear to be severe: a new National Development Plan under preparation in Bhutan is likely to include Samtse and its surrounding area as a zone for industrial and housing development (on account of its proximity to India), and both sites for B. bhutanica are likely to be destroyed if this development goes ahead. Even if the immediate sites were protected, nearby development would probably lead to abstraction of the water supplies from these valleys and the greatly increased human population would add to degradation and possibly over- grazing of these localities. In spite of the discovery of a second population of B. bhutanica, its status as Critically Endangered is fully justified and should be maintained. We strongly recommend that a search for further colonies in other parts of southern Bhutan be undertaken as soon as possible, and recommend to the Royal Government of Bhutan that future industrial development be zoned in a more appropriate area. References: Long, D.G., Gurung, B.R. & Pradhan, R. 2010. The rediscovery and conservation status of Bazzania bhutanica in Bhutan. Field Bryology No 101: 28--33. Author of this red data sheet: Dr. David G. Long, Head of Cryptogamic Plants & Fungi Section, Royal Botanic Garden, Edinburgh EH3 5LR, United Kingdom ————————————————————————————————————————— Last updated: April 2012 .

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