The variety of life forms, the different plants, animals and micro-organisms, the genes they contain, and the ecosystems they form. It is usually considered at three levels; genetic diversity; species diversity, and ecosystem diversity
It is important in Fiji’s context to specifically include the social element and in particular “Protect and encourage customary use of biological resources in accordance with traditional practices that are compatible with conservation or sustainable use requirements”. Article 10c Convention on Biological Diversity (IUCN, 1994)
Status of Biodiversity in Fiji
The current status of Fiji’s biodiversity is summarized in Table 2.1. There are two important points which are readily appreciated and very significant in respect of the FBSAP
Rotuma’s terrestrial biodiversity has elements which distinguish it from being merely a Fijian outlier as they are Central Pacific or Samoan in character. Similarly, Rotuma’s marine fauna has Central Pacific affinities (Zug et al. 1988). Consequently, Rotuma requires special consideration in biodiversity conservation.
The vascular flora of Fiji is regarded as an extension of the Indo-Malesian floristic province with about 90% of all seed plant genera found in Fiji being present in New Guinea (Balgooy 1971; Ash 1992). However, affinities do exist with Australia, Hawaii, New Caledonia, New Zealand and French Polynesia (Fuller, 1997).
The total number of vascular plants known from Fiji is approximately 2600 of which approximately 1600 are native and 1000 are Fijian flora consists of 310 pteridophytes (ferns and fern allies from Brownlie 1977) and at least 2225 seed plants (Watkins 1995). Based on Smith’s Flora Vitiensis Nova (1979-1991), the endemism of Fiji’s seed plants is estimated to be 56%, 893 of 1594 native species (FBSAP Technical Group 3,1998). Smith (1979-1991 records 934 introduced species but this is an underestimate based solely oh herbarium specimens. The correct figure is likely to be well over 1000 introduced species.
There is a single endemic family, Degeneriacease which has two species, and 10 of the approximately 450-470 genera are endemic. These are:
Degeneria (Degeneriaceae), Alsmithia (Arecaceae), Neovetchia (Arecaceae), Gillespeia (Rubiaceae), Hedstomia (Rubiaceae), Readea (Rubiaceae), Squamellaria (Rubiaceae), Sukunia (Rubiaceae), Amaroria (Simaroubaceae), Pimia (Sterculiaceae)
As to be expected in an isolated island flora, genetic radiation and endemism in some groups is extreme. For instances the genus Psychotria (Family Rubiaceae) is represented by 76 species of which 72 are endemic.
Palms are the best studied floral group in Fiji and the group documents very clearly the presence of highly restricted ranges, yet recent work shows how poorly we understand even this well-studied group. Doyle and Fuller (1998) have revised the palm flora to consist of 30 described species in 15 genera of which 14 genera and 24 species are considered indigenous, and of these, all 24 species and one genus are endemic to Fiji. All but one of Fiji’s endemic palms are forest species and the status of at least 12 (50%) are of conservation concern.
Adequacy of Our knowledge of Fiji’s flora
Although Fiji’s flora is well researched in comparison with those in the South Pacific archiepelagoes, there remain many localities that have never or scarcely been collected. New plant species are being discovered regularly, even though current floral research is minimal. On the basis on number of species known by only single collection it seems probable that there could be up to 200 species that remain undocumented.
The floristic diversity of Fijian forests has not been documented but it is greatly in excess of 100 species per kilometer square. It is likely that at least one thousand herbarium collections per 100 kilometers square are required to obtain a reasonable estimate of the floristic composition of an area and on this basis there are few, if any areas, in Fiji for which the species composition ids adequately known (Ash and Vodonivalu, 1989). As to be expected the distribution of Fiji’s endemic species is skewed heavily in favour of the larger islands (Viti Levu, Vanua Levu and Taveuni). Of the remaining islands, only Ovalau has significantly more endemic species than might be expected from its area. This probably reflects its status as a land bridge island formerly connected to Viti Levu in times of glacial maxima.
Terrestrial and Freshwater Invertebrates
Fiji’s invertebrate fauna has received little attention and many groups have not been studied at all. Research has tended to concentrate on those species of economic importance-plant pests etc. Literature on the other groups is scanty, well scattered in the scientific literature and not readily available in Fiji.
However, the following sections sunmmarise some of the more readily available data.
Robinson (1975) suggested that the total number of insect species inhabiting the Fiji group is in excess of 3500.
Molluscs and Crustacea
No review of Fijian terrestrial molluscs appears to have been undertaken, but Solem (1974) records 58 species for Viti Levu.
Birds are Fiji’s most conspicuous wildlife with:
- Over 120 species recorded
Fiji’s only indigenous mammals are bats of which there are six known species, four of which are large fruit bats(megachiropterans) and two are small insectivorous species (microchiropterans). One of the fprmer, the Fiji Flying Fox Pteralopex acrodonta is endemic. Feral populations of domesticated species excluded, there are five other introduced species now naturalized (Four rodents and the Indian mongoose Herpestes auropunctatus).
Fiji’s terrestrial reptile fauna consists of:
• 2 snakes (incl. one endemic genus);
Of a total of 26 reptile species, nine are endemic (35%). The single endemic genus is the elapid snake- Fiji Burrowing Snake Ogmodon vitanus.
Fiji has two little-know endemic frogs (genus Platymantis) both of which are endemic. One introducted species the giant toad Bufo marinus is naturalized widely.
Ryan (1980) provides a comprehensive list of Fijian freshwaters and brackish fish containing 96 recorded species, three additional species have also been recorded from Taveuni (Ryan, 1981). Four of these (4%) are endemic, though Ryan (loc.cit.) considers that this figure is likely to be increased on more intensive work on islands other than Viti Levu. Ten introduced specie are naturalized.
Fiji has an extensive and high diversity of marine habitats including estuaries, mangrove wetlands, seagrass, macroalgal assemblages, protected and exposed soft shores, lagoons, coral reefs and slopes. These support a rich biodiversity, and a major subsistence and moderate commercial fisheries. However, despite its subsistence, commercial and conservation value, Fiji’s marine biodiversity is not well known.
This is surprising considering the biogeographically strategic position Fiji has in the South Western Pacific, and the relatively large numbers of collections made by visiting scientists to the University of the South Pacific. However, Fiji’s marine biodiversity is much better known than most island groups in the region. Zann et al (1997) is the most recent review of Fiji’s marine biodiversity.
Although knowledge of the most taxa is very incomplete, it is evident that Fiji has high species diversity. Affinities lie strongly with the west, the Philippine/Indonesia/New Guinea center of Indo-Pacific marine species diversity, but with a reduction in species diversity (e.g Veron, 1995).This is because of the prevailing westerly flowing Subequatorial Current and trade wind drift, and the moderate isolation of Fiji from western island archipelagos (600 nautical miles from Vanuatu in the west, 1200 nautical miles from Solomon Islands I the north wets). The high marine biodiversity in Fiji is also due to the large number of different habitats within the group. Many of these are less well developed in islands to the east.
The Fiji Group receives a mall number of Central Pacific marine endemic and although a number of marine species are known only from Fiji, this reflects more the lack of collections in neighboring groups than a real trend of endemism.
Marine algae are important primary producers on coral reefs and groups such as the crustose coralline algae play a very important role in calcification and cementation processes on coral reefs. Several species of algae are edible and part of the traditional Fijian diet while species such as Ulva and Enteromorpha are key indicator species in environmental impact assessments of pollution in coastal and estuarine regions. The most complete list of the Fijian algal flora to date is the revised checklist by N’Yeurt et al (1996), listing 422 taxa.
Seagrass beds are found in the intertidal and in the shallow sub tidal in the more protected and soft shores through out Fiji. They have a very high biological productivity, are efficient recyclers of nutrients, and support a large biomass of consumers, especially those of fisheries importance. Four species of sea grass are common in Fiji.
The largest formations of mangrove in Fiji are found in deltas at the mouth of some of the large rivers in Ba, Rewa, Nadi, and Dreketi. Fiji has a considerable area of mangrove but the community is relatively simple by comparison with those of island and continental south-east Asia.
Fiji’s mangrove flora is composed of eight mangrove species and a unique hybrid. It is dominated by Bruguiera gymnorrhiza ( “dogo”), Rhizophora stylosa and Rhizophora samoensis (both “tiri”) and a sterile hybrid R.x selala (“selala) which is a cross between Rhizophora stylosa and Rhizophora samoensis. The naturally occurring hybrid Rhizophora x selala is of great scientific interest because it is only found in Fiji, Tonga and New Caledonia with Fiji having the greatest area of the hybrid (Watling 1985).
In addition there are many important mangrove associates. Pillai (1985) identified 33 species including mangroves and important mangrove-associated species represented in Fiji’s mangrove areas.
There are around one thousand coral reefs in Fiji (Zann, 1992). These are geologically recent structures (that is generally younger than 10,000 years old) forming a capping of biogenic limestone over previous reef formations. The major reef types are fringing reefs which surround almost all high islands and barrier reefs which lie at the edges of island shelves. Platform reefs lie in shallow island shelves. Several atolls and near atolls are present in the east.
A collection of Fijian stony corals is housed in the University of the South Pacific reference collection. Although the collection is far from complete, Pichon (1980) identifies 230 forms, about 200 of which to the species level (Pichon, 1980)
The lower invertebrates of Fiji are not well studied.
The molluscs (snails, bivalves, octopus etc) are very well represented in Fiji. The larger and more common species are particularly important in the subsistence diet of Fijians. Each year over 1, 000 MT of snails and bivalves are marketed but possibly 5-10 times that quantity is consumed at the subsistence level.
Because of their interest to shell collectors the Fiji molluscs have been very widely collected and are scientifically well described. The more spectacular cowries (Cypraeidae) andscones (Conidae) have attracted the most attention but even the less conspicuous species are reasonably well know. The most comprehensive Fiji collection was compiled by K. Gilchrist over the past 40 years; 7,000 specimens including around 760 species of Fijian gastropods and bivalves from this collection are now held by the Smithsonian Institution and 1,000 fossil species are held by the Australian Museum.
Fiji’s fish fauna is moderately well known. Although a number of species have been described from Fiji, subsequent collections outside the group have indicated that few, if any, are endemic. Fiji’s fish have strong zoogeographical affinities with the Western Pacific (Australian Plate) but with fewer species present. Springer (1982) noted that about 163 families were found on the Great Barier Reef, 125 in New Caledonia-Vanuatu, 118 in Fiji and 102 in Samoa. Springer (loc.cit.) proposed that the distribution of fish in the Pacific is related to the history ofplate tectonics.
A preliminary listing of reef, pelagic and deepwater bottom fishby Baldwin and Seeto (1986, unpubl.) contains a total of 1,198 species from 162 families (including pelagic deepwater bottom fish species). This listing will be substantially increased, perhaps to 1,500 species when the Springer, and Emery and Winterbottom collections are fully identified (J.Seeto).
Two species of sea turtles nest in Fiji, the green turtle Chelonia mydas and the hawksbill turtle Eretmochelys imbricate. Loggerheads Caretta caretta are present but uncommon. Flatbacks Chelonia depressa, Ridleys Lepidochelys olivacea and leather backs Dermochelys coriacea are occasional to rare visitors to Fijian waters.
Three species of sea snake breed in the Fiji Group, of these two are the amphibian banded kraits Laticauda colubrine, L.laticauda which breed on land. Hydrophus melanocephalus gives birth to live young at sea. The oceanic bellied sea snake Pelamis platuris is an occasional visitor (Guinea, 1980).
The marine mammals of Fiji are very poorly known. Zann et.al (1997) indicate that amount 13 species are likely to be found in Fiji, however, Jefferson et al. (1993) indicate that 16 whales and seven dolphins may be found in Fijian waters.
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