Gathering moss

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One of the least studied species in the country, they most often go unnoticed to many of us. They are found anywhere where there is enough water; whether it’s trees, fallen logs, roots, walls, buildings or rocks. However, despite their lack of popularity they continue to exist and new species are discovered from time to time by those interested in this unique type of plants. 

Mosses as they are known to need a damp location to grow, but will not do as well in a location that is swampy. They also like to grow in the shade, as moisture is more likely to linger in these areas and the moss will be less likely to dry out quickly. 

If conditions are favourable, moss will grow just about anywhere. In a shady forest, it can thrive on all sides of a tree – North, South, East, or West. Yet, trees offer other benefits to help mosses colonise and flourish. Tree bark is rough and irregular, and these cracks and crevices provide protected micro habitats.

H.K. Herath, N.C.S. Ruklani, and S.C.K. Rubasinghe of the Department of Botany, Faculty of Science of the University of Peradeniya have recently discovered three new species of mosses thereby bringing the total number of mosses in the country to 575.

“Mosses (Phylum Bryophyta) comprise the group of bryophytes (liverworts, mosses, hornworts) and consist of about 13,000 species worldwide. Owing to its high level of topographic and climatic heterogeneity, the tropical island of Sri Lanka supports a luxuriant growth of mosses. Compared to other groups of plants in the country, mosses remain a poorly researched group. Lack of proper taxonomic studies and scarcity of literature sources including locality details hamper further research in the field of bryology. The present study was carried out to explore the diversity of mosses in some selected localities of Sri Lanka,” Herath, Ruklani and Rubasinghe state in their research paper.

They say fresh samples of mosses were collected from different localities including the Horton Plains National Park, the Loolecondera Conservation Forest, the Kanneliya Forest Reserve, and the Badagamuwa Conservation Forest. “Samples were observed for their morphological and anatomical characters using dissecting, compound and scanning electron microscopes. The specimens were identified by following the recent classification systems, using the most recent taxonomic keys, and monographs,” the researchers explained.

The study identified three species records new to Sri Lanka including Brachymenium capitulatum (Mitt.) Kindb., Ctenidium pinnatum, and Fissidens crassinervis var. laxus.

“Sri Lanka is an island country lying in the Indian Ocean. The island is one of the most diverse regions in South Asia and is recognised as one of the world’s biodiversity hotspots along with the Western Ghats of India. Owing to its high level of topographic and climatic heterogeneity, Sri Lanka supports a luxuriant growth of a remarkably rich bryophyte (liverworts, mosses, hornworts) flora,” Herath, Ruklani and Rubasinghe say.

In contrast to the well-studied higher plant flora of Sri Lanka, bryophytes are still poorly explored, mainly due to their small size and difficult taxonomy. According to the recent checklists, the island harbours 327 species of liverworts, 560 mosses and five hornworts.

“Of the three phyla of bryophytes: Marchantiophyta (liverworts), Bryophyta (mosses) and Anthocerotophyta (hornworts), mosses are the most species rich group, including more than 13,000 species worldwide. The foundation for studies on mosses in Sri Lanka was laid down during the British colonial period. Alexander Moon (1817 – 1825) was the first to collect Sri Lankan bryophytes, and some of his specimens are deposited at the Natural History Museum, UK, which have not been studied or published yet. A checklist compiling all the published literature was published by Brian O’Shea (2002). O’Shea’s checklist recorded 60 families, 174 genera and 560 species of mosses from Sri Lanka,” the researchers say.

They go on to say that this checklist has not been updated to date and the country lacks a specimen-based checklist or a flora of mosses. “For most of the published taxa of mosses, locality details and descriptions are lacking and more localities still remain underexplored for bryophytes. However, a few contributions to the moss flora have been made since O’Shea’s checklist. Benito Tan (2005) reported five new species of mosses based on a collection made at Hantana Ridge and Loolecondera Tea Estate,” the researchers said.

Seven new species were reported by Ruklani and Rubasinghe in 2013 from the Central Province. These reports highlight the necessity of proper systematic studies on the moss flora of the country.

A series of taxonomic surveys were conducted at different geographic localities in Sri Lanka including Horton Plains National Park, Loolecondera Conservation Forest, Kanneliya Forest Reserv,e and Badagamuwa Conservation Forest. Fresh samples of mosses were collected and thoroughly surveyed for morphological and anatomical characters. Specimens were identified using taxonomic keys, descriptions and monographs and authenticated using type descriptions and/or specimens. Voucher specimens were prepared and deposited at the National Herbarium, Peradeniya.

“The four selected localities explored during the study revealed a considerable diversity of mosses including 23 families, 46 genera and 63 species. Calymperaceae, Fissidentaceae, Leucobryaceae, Meteroriaceae, Neckeraceae, Bryaceae, Dicranaceae, Thuidiaceae and Sematophyllaceae were the commonly encountered families during the study. Horton Plains National Park comprised the highest species diversity and luxuriant growth of mosses while Badagamuwa Conservation Forest showed the least species diversity and sparse growth of mosses. Deforestation, clearance of roadsides and climate change are the main threats to the moss flora of Sri Lanka,” the researchers explain.

They add that although Sri Lanka harbours a high diversity of bryophytes, there is no specimen based checklist nor a ‘Flora’ for bryophytes of Sri Lanka. “Documents describing their morphology, identification methods, distribution patterns, locality and phonological details is lacking for most groups of bryophytes including mosses. This scarcity of information and expertise in the field prevent further research carried out on this important group of plants within the country. Also, due to the same reason, it is a barrier to identify the important sites for bryophyte conservation,” Herath, Ruklani and Rubasinghe say.

The study emphasises the importance of identification and documentation of the existing bryophyte flora of Sri Lanka so that necessary conservation measures could be implemented to conserve the existing taxa before they disappear from the country.

By Risidra Mendis