This BioProvince (as defined by Armen Takhtajan) comprises the Bismarck Archipelago, the Admiralty Islands and the Solomon Islands, and all lie within the Pacific zone of Melanesia. They are largely composed of Tertiary to Recent lavas and volcanically derived sediments, and have substantial limestone beds overlying basements of older schists and plutonic rocks. Serpentine and other intrusive ultrabasic rocks are also a prominent feature of certain islands. They experience a tropical, wet climate with the Solomons being one of the wettest regions on the Planet. The almost permenant cloud cover give them a sombre appearance and this has been suggested as one possible explanation for the term Melanesia or dark islands. Most parts have their maximum rainfall in January or February with the exception of the so-called ‘weather coasts’ of the big eastern islands such as Guandalcanal and San Cristobal. These, exposed to the southeast and backed by high mountains, have a mid-year peak. Nowhere experiences a distinct dry period and no regular seasonality has been observed in changing leaves or flowering of plants. However, located on the northern edge of the southwest Pacific tropical cyclone belt, large areas of forest are periodically devastated by typhoon winds. The rich flora includes five endemic genera (Allowoodsonia, Cassidispermum, Clymenia, Homalocladium, Kajewskiella and Whitmorea), with all but one of these (Clymenia) confined to the Solomon Islands. In fact, there is justification for considering the Solomon Islands on the one hand, and the Bismarck Archipelago and the Admiralty Islands on the other, as distinct sub-bioprovinces in their own right. The flora in general has been decribed as an attenuated version of the Papuan flora and has many similarities with the Malesian Region, but there is also a small Pacific element. For example, Solomon’s monotypic Lepinia solomonensis also occurs on Ponape and Tahiti. Interestingly, though, despite its closeness, there is no Australian element to the flora.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|