Taxonomy and Conservation Status of Pteridophyte Flora of Sri Lanka R.H.G. Ranil and D.K.N.G. Pushpakumara University of Peradeniya Introduction The recorded history of exploration of pteridophytes in Sri Lanka dates back to 1672-1675 when Poul Hermann had collected a few fern specimens which were first described by Linneus (1747) in Flora Zeylanica. The majority of Sri Lankan pteridophytes have been collected in the 19th century during the British period and some of them have been published as catalogues and checklists. However, only Beddome (1863-1883) and Sledge (1950-1954) had conducted systematic studies and contributed significantly to today’s knowledge on taxonomy and diversity of Sri Lankan pteridophytes (Beddome, 1883; Sledge, 1982). Thereafter, Manton (1953) and Manton and Sledge (1954) reported chromosome numbers and some taxonomic issues of selected Sri Lankan Pteridophytes. Recently, Shaffer-Fehre (2006) has edited the volume 15 of the revised handbook to the flora of Ceylon on pteridophyta (Fern and FernAllies). The local involvement of pteridological studies began with Abeywickrama (1956; 1964; 1978), Abeywickrama and Dassanayake (1956); and Abeywickrama and De Fonseka, (1975) with the preparations of checklists of pteridophytes and description of some fern families. Dassanayake (1964), Jayasekara (1996), Jayasekara et al., (1996), Dhanasekera (undated), Fenando (2002), Herat and Rathnayake (2004) and Ranil et al., (2004; 2005; 2006) have also contributed to the present knowledge on Pteridophytes in Sri Lanka. However, only recently, Ranil and co workers initiated a detailed study on biology, ecology and variation of tree ferns (Cyatheaceae) in Kanneliya and Sinharaja MAB reserves combining field and laboratory studies and also taxonomic studies on island-wide Sri Lankan fern flora. As a result, Ranil et al. (2010a; 2010b) have described two new pteridophyte species from Sri Lanka and identified conservation priorities for Sri Lankan tree ferns in 2011 (Ranil et al., 2011). Ranil et al., (in prep.) reviewed and revised the list of endemic pteridophytes in Sri Lanka. Currently, about 348 pteridophyte taxa from 30 families have been recorded from Sri Lanka, of which 50 taxa are reported to be endemic to the country (Shaffer-Fehre, 2006). Among Asian countries, Sri Lanka is second only to Taiwan in terms of the number of pteridophyte species per 10,000 km2 (Ranil et al., 2008a). Geographical isolation, and a wide range of climatic, elevational and soil type variation in Sri Lanka may have resulted in rich diversity of pteridophyte flora as well along with exceptionally high level of endemism. It is reported that Sri Lankan pteridophytes have strong phyto-geographical relationships with South Indian species. Further, both the Sri Lankan and the South Indian pteridophyte flora also have phyto- geographical relationship with three regions, namely the Sino-Himalayan flora, the Malesian flora from South East Asia, and an African element connected with the Seychelles, Mascarenes, Madagascar and East Africa (Fraser-Jenkins, 1984). Despite historical and recent information on pteridophyte flora of Sri Lanka, this is the first instance that the pteridophyte flora has been assessed based on the national Red Listing criteria. 148 Taxonomy The present knowledge of ptridophytes is largely based on Shaffer-Fehre (2006) which is mainly based on morphology and specimens of existing herbarium collections rather than new information. It has been prepared during 1993-1995 period but published in 2006. However, with the advancement of plant molecular studies, taxonomic status of many fern species have changed and many revisions have been made. On the other hand, recently an extensive field survey of South Indian fern flora has been carried out, though such information has not been widely published yet. Recent review of endemic pteridophyte flora in Sri Lanka parallel to information generated through South Indian survey via personal communication revealed that the changes of number of endemic taxa from 50 (Shaffer-Fehre, 2006) to 44 (Ranil et al., in prep.). All these indicated the need of a systematic review of the taxonomy of Sri Lankan pteridophytes based on detailed field works and existing herbarium collections and also considering with advances of taxonomy and systematics due to molecular studies on pteridophytes. For the red listing process, except for three families, namely Aspleniaceae, Cyatheaceae and Thelypteridaceae (where there is no agreement among pteridologists to place Sri Lankan species within families, hence followed Shaffer-Fehre (2006), all species have been arranged based on the linear sequence of extant families and genera of lycophytes and ferns proposed by Christenhusz et al., (2011). Changes of genera and families according to Christenhusz et al. (2011) are given in Table 1. Table 1: Changes of genera and families based on recent classification proposed by Christenhusz et al. (2011). Flora of Ceylon (2006) by Redlist (2012) based on Chris- Taxa Shaffer-Fehre (2006) tenhusz et al. (2011) Genera Antrophyum Vittariaceae Pteridaceae Arthropteris Oleandraceae Tectariaceae Athyrium Woodsiaceae Athyriaceae Bolbitis Lomariopsidaceae Dryopteridaceae Ceratopteris Parkeriaceae Pteridaceae Deparia Woodsiaceae Athyriaceae Diplazium Woodsiaceae Athyriaceae Elaphoglossum Lomariopsidaceae Dryopteridaceae Hypodematium Woodsiaceae Hypodematiaceae Leucostegia Davalliaceae Hypodematiaceae Lindsaea Dennstaedtiaceae Lindsaeaceae Loxogramme Loxogrammaceae Polypodiaceae Lygodium Schizaeaceae Lygodiaceae Monogramma Vittariaceae Pteridaceae Nephrolepis Oleandraceae Nephrolepidaceae Pteridrys Dryopteridaceae Tectariaceae Sphenomeris Dennstaedtiaceae Lindsaeaceae Tectaria Dryopteridaceae Tectariaceae Teratophyllum Lomariopsidaceae Dryopteridaceae Vittaria Vittariaceae Pteridaceae Family Grammitidaceae Grammitidaceae Polypodiaceae 149 Distribution Limited research has been conducted to identify distribution of pterdophyte flora in Sri Lanka. About 81% of pteridophyte specimens in the National Herbarium have been collected from the wet zone area of the country (Jayasekera and Wijesundara, 1993). The wet zone which accounts for only one third of the country’s total land area also contains almost all endemic pteridophytes except one species (Ranil et al., in prep.). Further, study on distribution pattern of endemic pteridophyte flora of Sri Lanka revealed that those are more-or-less equally distributed among the wet zone areas of the up, mid and low countries with 34, 31 and 32 taxa, respectively (Ranil et al., 2008a). Majority of endemic pteridophytes (78%) of Sri Lanka had been collected from the Central Province where Nuwara Eliya district alone provided the highest number of endemic taxa collected with 34 taxa followed by Sabaragamuwa and Southern provinces. Even though some species occur in a few districts, their known occurrence has been limited only to a few isolated localities (i.e. Cyathea hookeri, C. sinuata, C. sledgei and C. srilankensis; Ranil et al., 2010a; 2010b). Long duration of rainfall and high relative humidity associated with elevational gradient may be one of the reasons for the presence of higher number of endemic taxa in the wet zone and the Central Province. In addition, close proximity to the Botanical Gardens of Peradeniya and Hakgala had also influenced a higher number of species collections from the Central Province and Nuwara Eliya district. A B C Endemic and endangered tree ferns in lowland rainforests. A: Cyathea sledgei Ranil et al.,: A recently described new endemic tree fern species in Kanneliya MAB reserve. B: Cyathea srilankensis Ranil: A recently discovered new endemic tree fern species in Beraliya proposed forest reserve. C: Cyathea sinuata Hook. & Grew.: The only known simple leaf tree ferns in the world. A B Two endemic ferns species in southern lowland rainforests. A: Tectaria thwaitesii (Bedd.) Ching: An endemic fern species in roadside banks of Kottawa forest reserve. B: Oreogrammits sledgei (Parris) Parris: An endemic fern species grows on moist rock in Sinharaja world heritage site. 150 Threats Vast majority of pteridophyte flora and almost all endemic pteridophytes in Sri Lanka are confined to the wet zone areas of the lowland, sub montane and montane regions. However, most of the remaining forests in the wet zone area are fragmented and small. They are continued to be degraded due to illegal encroachment and suffer further fragmentation due to higher population densities in such areas. The area is highly subjected to habitat loss, spread of alien-invasive species, soil erosion and environmental pollution. These are considered as the most immediate threats to the pteridophyte flora of Sri Lanka. In areas such as the Knuckles region, the forest understorey which is the main habitat for pteridophytes has been cleared for cardamom cultivation whereas in Udawattakele forest understorey is invaded by alien-invasive species; also make significant threats to regeneration of pteridophytes. Another threat of increasing importance is the illicit removal and over exploitation of ornamentally important rare ferns from the wild. These problems will be worsening by change of climate and increasing human population pressure. Conservation issues The effective conservation of Sri Lankan pteridophyte flora will depend largely on how effective the conservation of natural forests in the wet zone areas of the country. For this, minimizing of fragmentation and habitat loss through effective land use planning