Botanical Studies within the PABITRA Wet - Zone Transect , Viti Levu , Fiji

Botanical studies along mountain-to-sea transects are a key component of the Pacific-Asia Biodiversity Transect (PABITRA) project. For the Fiji PABITRA Wet-Zone Transect, it is suggested that four basic categories of biodiversity data (species inventory, plant community description, ecological data on the species and community level, and long-term monitoring) be collected within the seven biodiversity study sites (Mt. Tomaniivi/Wabu, Monasavu, Sovi Basin, Waisoi, Waibau, Savura, and Nasoata/Valolo Islands) covering an elevational gradient from sea level to 1,300 m. Currently, Sovi and Waibau are without data, except for vegetation descriptions based on aerial photographs. However, data from baseline surveys is now available for Sovi. Most of the data available on Mt. Tomaniivi/ Wabu and Savura are extrapolated from collections and studies in adjacent areas, but in both areas data collection has recently begun. Only Waisoi and Nasoata/ Valolo have species checklists and descriptions of the various plant communities, with ecological studies having been conducted only in the former. Because basic data (species lists, plant communities) are lacking in many areas, obtaining such data is a primary objective of PABITRA in Fiji. Other issues that should be considered are inclusion of other sites in the network of focal sites and a standardized way of data entry and basic data analysis. Fiji, as an oceanic island group located between 15 and 22 S and 177 W and 175 E in the South Pacific Ocean (Figure 1), has a unique flora that is a depauperate and disharmonic version of the Malesian flora (van Balgooy 1971). The archipelago comprises about 500 named islands with an estimated land area of 18,325 km, covering a total area of about 650,000 km. Viti Levu (10,388 km) and Vanua Levu (5,535 km) compose the bulk of the land area (Mueller-Dombois and Fosberg 1998). Several botanical explorations (summarized by Smith 1979) resulted in two floras: the first by Seemann (1865–1873), followed by the more comprehensive Flora Vitiensis Nova (Smith 1979, 1981, 1985, 1988, 1991, 1996). Mainly based on Smith’s flora, Watkins (1995) reported about 2,225 plant species from Fiji with 58% (or about 1,290 species) being native, of which 63% (or some 813 species) are considered endemic. However, Ash (1992) reported 1,769 native species with about 400 endemics (22%). In any case, these values need revision because of description of new species (e.g., Fuller et al. 1997, Fuller and Dowe 1999), amalgamation of species (e.g., Whitmore 1980), introduction of new species (e.g., Keppel 1999), and reported range extension for species previously thought to be endemic to Fiji (e.g., Wheatley 1992). Despite the extensive documentation of Fiji’s flora, vegetation and ecological studies are few. Ash (1992) summarized most of these studies but omitted some, such as those on Mt. Korobaba (Kirkpatrick and Hassal 1985, Hassal and Kirkpatrick 1985) and the Sigatoka Sand Dunes (Kirkpatrick and Hassal 1981). Berry and Howard (1973a,b) conducted an inventory of the various forest types based on aerial photographs mainly for forestry purposes. They identified 41 forest Pacific Science (2005), vol. 59, no. 2:165–174 : 2005 by University of Hawai‘i Press All rights reserved 1 Manuscript accepted 23 April 2004. 2 Biology Department, School of Pure and Applied Sciences, University of the South Pacific, Suva, Fiji (e-mail: [email protected]). types. Unfortunately their account does not include a detailed map that shows the various vegetation types in Fiji. Although their study provided much information on the likely distribution of the various forest types in Fiji, field verification of forest types was restricted to certain sample locations. It is therefore questionable to what degree the results can be extrapolated to remote areas such as the Sovi Basin and the Wabu catchment. Also, because the study was conducted for forestry purposes, it focused on timber species. The various vegetation types in Fiji were identified and summarized by Mueller-Dombois and Fosberg (1998). Fiji was one of the original transects of the Pacific-Asia Biodiversity Transect network (PABITRA) proposed at the 9th Pacific Science Inter-Congress in November 1998 in Taipei, Taiwan (Mueller-Dombois et al. 1999), and was designated as a Gateway Site of the PABITRA project at the 19th Pacific Science Congress in Sydney in July 1999. Because Fiji consists of more than 500 islands that compose a land area of more than 18,000 km within a total area of about 650,000 km, a representative area had to be selected. A transect stretching from the highest peak, Mt. Tomaniivi (formerly Mt. Victoria), on the largest island, Viti Levu, to the barrier reefs beyond the delta of Fiji’s largest river, the Rewa, was chosen because it best satisfied the objectives of PABITRA (MuellerDombois et al. 1999). Because this transect still includes a total area of more than 2,000 km, representative sites at which studies will be concentrated (here called ‘‘focal sites’’) were chosen. Seven focal sites (Mt. Figure 1. Approximate location of the PABITRA Wet-Zone Transect in the Fiji Group. PACIFIC SCIENCE . April 2005 166