International Journal of Science and Research (IJSR) ISSN: 2319-7064 Impact Factor (2018): 7.426 Volume 8 Issue 2, February 2019 www.ijsr.net Licensed Under Creative Commons Attribution CC BY A Review on the Floral Composition of Kanneliya - Dediyagala - Nakiyadeniya (KDN) Forest Complex in Sri Lanka M. D. K. L. Gunathilaka Department of Geography, University of Colombo, Sri Lanka Abstract: Kanneliya - Dediyagala - Nakiyadeniya (KDN) forest complex is an international biosphere reserve belongs to the lower wet bio-climatic zone. The area is significant for exceptional plant endemicity. Due to the selective logging, exotic species like Alstonia macrophylla and Swetinia macrophylla have become pioneers of the forest area. This study is a literature-based review on the plant species in KDN forest complex with the objective to assess the floristic richness of KDN forest complex. Available studies from 1985 up to 2017 reported various information on the floral composition, diversity and abundance, ecological sensitivity and conservation providinga more distinct view on KDN forest complex. Calculating Important Value Index for plant families, most studies have identified Kanneliya as the core area among the three reserves than Dediyagala and Nakiyadeniya. The topography of the Kanneliya forest reserve area made it as the core area while Nakiyadeniya also reported for high floristic richness. The floristic richness recorded from Dediyagala forest reserve is lower, compared to other two reserves. Kanneliya also identified as a prominent lower wet zone forest for moss flora where species belonging to13 families and 21 genera recorded. This shows the necessity of conservation of plant species in KDN forest complex. Keywords: Conservation, Endemicity, Exotic Species, Floristic richness, KDN forest complex 1. Introduction Sri Lanka is a tropical island located in the Indian Ocean, with a total land area of 65610km2. The forest cover in Sri Lanka has been continuously and rapidly declined during the last several decades. The total forest cover in 1999 was 2.02 million hectares, representing approximately 30.5 per cent of the total land area. However, the remaining natural forest cover in 2003 was 1.46 million hectares which were around 22.4 per cent of the land area [1]. The only aseasonal ever wet region in the whole of South Asia is the well-known southwestern region of Sri Lanka [2], [3]. This wet zone of Sri Lanka along with the Western Ghats of India (Figure 1) is designated as one of the world’s biodiversity hotspots (Figure 1), in demand of extensive conservation investment [4], [5]. Once, Sri Lanka was a part of the ancient Gondwanaland and was located adjacent to the African continent. The Deccan plate which comprised of India and Sri Lanka (Figure 2 a.), broke away from the Gondwanaland, drifted northwards and collided with the Asian plate around 55 million years ago(Figure 2 b.). Later on, Sri Lanka separated from the Indian mainland due to submersion of the land bridge between India and Sri Lanka about 20 million year ago. Accordingly, these zoogeographic, climatic, topographic and edaphic factors have affected the floral assemblages seen in Sri Lanka. Figure 1: Biodiversity hotspots in the world [4] 2. Kanneliya–Dediyagala-Nakiyadeniya forests complex The Kanneliya – Dediyagala – Nakiyadeniya (KDN) forest complex is located in the Southwestern part of Sri Lanka, at 6 09’- 6 18’ North and 80 19’ – 80 27’ East (Figure 3). The total area of the KDN complex was 10,139 hectares (KDN forest complex-conservation management plan, 1995) and the extent was rapidly decreased to 6114.4 hectares [6]. Kanneliya is the largest forest of the three conjoined forests which has been identified as a Man and Biosphere reserve. The entire KDN complex has been subjected to selective logging for seventeen years, from 1970 to 1987. As a result, a number of native plants species have removed from the forest complex and new plant species like Alstonia macrophylla and Swetinia macrophyllawere introduced to the forest complex. Paper ID: ART20195610 10.21275/ART20195610 2216