Floristic Composition, Vegetation Structure, and Diversity Pattern of Mt. Calavite Wildlife Sanctuary: Basis for Management and Conservation Planning

Abstract

Mt. Calavite Wildlife Sanctuary (MCWS) is regarded as home to more than a hundred species of plants, but its floristic composition, vegetation structure, and diversity pattern remained unclear since its declaration as a protected area. After the recent plant diversity assessment conducted following the prescribed methodology by the DENR–Biodiversity Management Bureau, the conservation value of the mountain was emphasized. This paper provides a concrete evidence that MCWS is home to diverse yet unique species of plants. A total of 181 morpho–species belonging to 67 families were recorded. MCWS now holds a large number of species of at least 250 morpho–species based on the assessment and gathered secondary data. Thirty–three (33) are threatened and forty–six (46) species are endemic to the Philippines. Four (4) species are known to occur only in MCWS, namely – Ardisia calavitensis Merr., Peristrophe cordatibractea Merr., Urophyllum mindorense Merr., and Cyrtochloa mindorensis S. Dranf. Majority of the species (about 67%) recorded are non–endemic indigenous. Dominant species in MCWS from 200 masl to 600 masl were also revealed. Mostly are species belonging to Fabaceae, Lauraceae, Malvaceae, Moraceae, Myrtaceae, Phyllanthaceae, Rubiaceae, Sapindaceae, and Sterculiaceae. MCWS, being comprised of a mosaic of different vegetation from grassland to secondary forest, has generally a stunted vegetation due to harsh environmental condition. The stratum of the forest of MCWS is unique because some species were recorded to a particular forest layer, allowing other species to coexist. Plant diversity pattern of MCWS showed weak correlation to elevation. The need to protect the mountain is further supported by the computed Shannon index (H =4.41) that indicates very high diversity.