The Solomon group EBA comprises the islands of Bougainville and Buka (politically part of Papua New Guinea), and Choiseul, Isabel, Malaita, the New Georgia group, Guadalcanal and Makira (or San Cristobal), as well as many smaller associated islands (all these belonging to the political Solomon Islands). The EBA does not include Rennell and Bellona (EBA 199), Temotu Province (part of EBA 200), or the atoll of Ongtong Java (Secondary Area s126); these are also all politically part of the Solomons.

The native vegetation is primarily lowland and montane rain forest, with fire-induced grasslands (which are extensive, for example, in the rain-shadow area of northern Guadalcanal and in the Nggela Islands) and mangroves. Montane forest on the highest islands is divisible into a lower montane zone between c.600 and 1,200 m, and an upper zone where the trees are stunted, the canopy is more open, palms and Pandanus abound, and mosses cover much of the ground (Hadden 1981).

This EBA has more restricted-range bird species than any other. The majority of them inhabit lowland and lower montane forest up to c.1,500 m, with a handful being confined to upper montane forest. Many of the altitudinal ranges given in the 'Status and habitat' table may be correct for the mountainous islands (e.g. Bougainville, Guadalcanal), but the occupied zones might be lower down on the lower islands; on Makira the altitudinal information is largely based on surveys up to 900 m only. Recent information on most of the species can be found in Buckingham et al. (1995).

Different species have different patterns of island distribution, and several islands and island groups have their own endemics: Bougainville (four endemic species), Choiseul (one, now extinct), New Georgia group (10), Malaita (three), Guadalcanal (two) and Makira (12). Within the New Georgia group, the islands of Vella Lavella, Ranongga and Ghizo each have one endemic species, and Kolombangara has two. The additional 30 restricted-range species endemic to the Solomon group EBA (in various island combinations), and 10 restricted-range species which occur in the group and elsewhere, combine all the islands into one EBA, although it is clear that several islands, notably Makira and the New Georgia group, are important areas of endemism in their own right.

Several of the more-widespread restricted-range species occur in other Papuan island and Melanesian EBAs, both further north into the Bismarck archipelago (EBAs 193-195) and south to Vanuatu (EBA 200) and New Caledonia (EBA 201).

In general the avifauna of this EBA is little known (e.g. Gallirallus rovianae was not discovered by ornithologists until 1977 and only described in 1991: Diamond 1991a) and many species had not been seen for decades until recently (Diamond 1987): for example, Nesoclopeus woodfordi (not recorded between 1936 and 1985), Columba pallidiceps (not recorded in the Solomon Islands after 1928 until re-found in 1987 on Guadalcanal and in 1990 on Makira), Actenoides bougainvillei (not reliably reported between 1953 and 1994), Pitta anerythra (not reliably recorded 1936-1994) and Rhipidura malaitae (not recorded 1930-1990). Gallinula silvestris is known only from a 1929 type-specimen and Gallicolumba salamonis has not been recorded since 1927, but as Makira's swamps appear never to have been visited by ornithologists, and the primary forest on the south coast not since the 1950s, they have not been classified as extinct. On the other hand, information relating to Microgoura meeki (last reliable record 1904) tends to confirm that this highly distinctive species in a monotypic genus is indeed extinct.

The taxonomy of this EBA's birds has been little studied. Some allopatric taxa may be judged full species in the future, e.g. the proposed Guadalcanal Thrush Zoothera (margaretae) turipavae which is treated as a species by Gibbs (1996b).

In addition to the restricted-range land birds, two seabirds suspected of having small breeding ranges are likely to occur within this EBA: Beck's Petrel Pterodroma becki is known from two specimens taken at sea in 1928 and, if it survives at all, Bougainville is a likely place for it to breed; Heinroth's Shearwater Puffinus heinrothi is known only from a small number of specimens, and could also breed in the Crown Prince range of Bougainville (Hadden 1981), or in the forested mountains of Kolombangara.

Although montane forest in the Solomon Islands is (at least superficially) mostly intact, large areas of lowland forest below 400 m have been logged for commercial timber extraction or are committed to logging, and much of the coastal area on many islands has been converted to coconut plantations.

It can be argued that all species which occur in lowland and hill primary forest are threatened because of current and proposed logging activities on most of the large islands and on some of the smaller ones (M. C. Garnett in litt. 1993, T. Leary in litt. 1993). However, some species have been recorded from secondary forest and thus their futures may be relatively secure, but there has been little research on survivorship in these habitats to verify this. The situation is further complicated by the decreasing quality (to wildlife) of regenerating forest because the fallow period between successive gardens is becoming reduced to increase the availability of land to meet increasing demands for subsistence farming (Buckingham et al. 1995).

Terrestrial birds, e.g. Gallicolumba salamonis, are additionally under threat from predation by rats, cats, dogs and pigs, and this is likely to worsen as areas are logged, opened up and become populated (G. C. L. Dutson in litt. 1993, K. D. Bishop in litt. 1996). On Guadalcanal cats have wiped out most native terrestrial mammals (T. Flannery per K. D. Bishop in litt. 1994), and cats and rats have been seen at high altitudes on a number of islands (T. Leary in litt. 1993). Some species are considered threatened on account of their tiny ranges, e.g. Phylloscopus amoenus (summit of Kolombangara only) and Zosterops luteirostris (Ghizo only). Hunting is common and may also become a problem for some species, especially forest pigeons, as village populations increase and habitat is reduced (A. Lees in litt. 1993).

Leary (1991) has synthesized information on the state of the Solomon Islands' natural resources, and also gives details of relevant environmental issues. Although most of the land (87%) is under village stewardship rather than government control, there are a few state-protected areas within the islands; Queen Elizabeth National Park on Guadalcanal is one such, but this has been slowly degraded since it was established and is now mostly cleared (G. C. L. Dutson in litt. 1993, K. D. Bishop in litt. 1996).

In 1990 a survey was undertaken to identify a representative system of protected forest areas, including reserve proposals for each of the main islands (Lees 1991), and progress is now being made to establish forest conservation areas that meet the cultural and economic aspirations of the indigenous forest owners (A. Lees in litt. 1993; see also Biliki 1993). A conservation and development programme is currently underway to establish a 630-km² reserve in the central Makira-Bauro highlands. This will protect the last extensive, accessible, lowland forest that remains uncommitted to timber production, along with a complete forested altitudinal transition across the island (Lees 1991, A. Lees in litt. 1996).

There is no recent information on the status of birds or forests in Bougainville owing to political unrest; the southern segments of the Crown Prince range, including Mts Takuan and Taraka and Lake Lorolu, have been identified by Beehler (1993) as areas which are important for terrestrial biodiversity.

Stattersfield, A. J., Crosby, M. J., Long, A. J. and Wege, D. C. (1998) Endemic Bird Areas of the World. Priorities for biodiversity conservation. BirdLife Conservation Series 7. Cambridge, UK: BirdLife International.

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Solomon group. Downloaded from https://datazone.birdlife.org/eba/factsheet/198 on 22/12/2024.