Floral survey of Laiban sub-watershed in the Sierra Madre Mountain Range in the Philippines

Abstract

The Laiban sub-watershed is part of the Kaliwa watershed nestled in the Sierra Madre Mountain Range in Luzon Island, Philippines. The watershed was identified as one of the 14 priority biodiversity conservation sites within the Sierra Madre Biodiversity Corridor. This study presents the results of the vegetation survey, which aimed to characterize various vegetation types and determine species richness and composition. Endangered, rare and endemic species were also identified. Land uses were surveyed and representative vegetation types were selected using patch and quadrat sampling techniques. Existing trail systems served as transect lines in conducting the rapid vegetation assessment during the transect walk. A total of 121 species belonging to 102 genera and 56 families were recorded during the survey. Of the 121 species recorded, 20% of these were endemics. Indigenous species comprised about 53% while exotic species was 27%. Many of the abundant and common plants were exotics and indigenous species, which comprised majority of the total species recorded. The endangered species consisted only 4% of the total species recorded. The vegetation types identified were: 1) secondary forests that are scattered in patches along the slopes; 2) grassland, which could be seen with distinct boundaries; 3) plantation forest; and 4) bamboo (Schizostachyum lumampao) that may be the dominant vegetation. The subwatershed is degraded and characterized by the presence of kaingin areas, grasslands, Buho bamboo (S. lumampao) and fragmented patches of secondary forests and brushland mosaics.