Species richness and distribution of pteridophytic flora in Dunumadalawa forest reserve, Kandy district, Sri Lanka: a preliminary survey

Abstract

Dunumadalawa Forest Reserve, located at 7⁰ 17'00" N; 80⁰38'49" E and 548 - 972 m above sea level and popularly known as Wakarawatte, is a semi-isolated, mid-country, wet zone forest fragment. It comprises mainly of secondary growth forest since the site has been used for tea and cocoa plantations in the past. The forest is not explored floristically, and the species composition of flora and its diversity has not been studied yet. In addition to the forest trees, the ecosystem setting provides an ideal habitat for pteridophytic flora, which grows opulently in the damp and shaded understory and as epiphytes. Preliminary observations and the sample collection of pteridophytes were carried out over a one-year period in several locations of the forest. Collected specimens were tagged and dried, and herbarium specimens were prepared. Species were identified using morphological characters with the aid of available literature. Identified species were verified with the help of specimens deposited at the National Herbarium of Sri Lanka, Royal Botanic Gardens, Peradeniya, Sri Lanka. A total of 10 families of Pteridophytes from different habitats were recorded, consisting of 15 genera and 30 species. Family Pteridaceae was the dominant family, represented by 15 species, followed by the Family Polypodiaceae consisting of four species. In addition, families, Tectariaceae (3 spp.), Thelypteridaceae (2 spp.) and one species each from the families Marattiaceae, Selaginellaceae, Gleicheniaceae, Nephrolepidaceae, Blechnaceae and Anemiaceae were recorded. A majority of fern species collected in this study were terrestrial species except for Pyrrosia lanceolata (L.) Farw., Microsorum scolopendrium (Burm.f.) Copel., and Drynaria quercifolia (L.) J. Smith was epiphytic. Among the terrestrial ferns, Blechnum occidentale L. wasthe most abundant and widely distributed species, which grows well, forming thickets in many places. According to the national Red List Sri Lanka 2020, among the 30 species of Pteridophytes recorded, 27 species were locally common, two Vulnerable (Tectaria polymorpha (Wall.ex.Hook.) Copel, Chirstella hispidula (Decne) Holttum.) and Selaginella crassipess Spring. Near Threatened. This study provides baseline taxonomic information to assist sustainable conservation and management activities of the pteridophytic flora in Dunumadalawa Forest Reserve.