Terrestrial (1), Nusa Tenggara and Maluku
Biodiversity and Tropical Forests in Indonesia.

The plant diversity in the Inner and Outer Banda Arc islands is essentially the same. A total of 407 endemic species and five genera of plants are known from Nusa Tenggara and Maluku, of which only eight species are shared between Nusa Tenggara and Maluku. The endemic genera are Septogarcuinia (Sumbawa), Sautiera and Sinthraoblastes (Timor), Parakibara (Halmahera) and Pseudsmelia (Halmahera and Moratai). The highest number of endemic species is on Lombok and Timor Islands, with 10% and 10.3 %, respectively. Western and eastern floral elements within these islands have no obvious demarcation boundary and Wallace’s line has no significance for plants between Bali and Lombok Islands.

Both Indo-west Malesian and eastern genera and species are moderately represented in Nusa Tenggara, the former being mainly rainforest plants and the latter being a mix of rainforest and seasonal species. All families of west and east Malesia are found in Nusa Tenggara, except for minor rare families (van Steenis 1979).
Most of the vegetation structural types found in other major islands reported in this report also occur in Nusa Tenggara and Maluku.

Lowland Evergreeen Rainforests are common throughout Nusa Tenggara and Maluku, generally on the drier slopes of Nusa Tenggara and Maluku. In the more arid parts of the region, pockets of lowland forest and gallery forest are often restricted to ravines. The most important expanses of tropical Lowland Evergreeen Rainforest are in central and north Maluku. These have a high proportion of dipterocarps, similar to densities found in Malaysia (Jones and Darsidi 1976).

One form of this forest is the structurally complex tropical Semi-Evergreen Rainforest, which is transitional between the Lowland Evergreeen Rainforest and Monsoon Forest. The Semi-Evergreen Rainforest is characterized by having low, pure stands so that the diversity of plants is less than in Lowland Evergreen Forests. Deciduous trees may be up to a third of all the taller species. The dipterocarp, Dipterocarpus retusus, is the only species in this family that occurs in Nusa Tenggara, where it is restricted to the western areas. On Sumbawa this species is replaced on drier slopes by the Sumbawan endemic, Heritiera gigantean. Eight species of dipterocarp are known from the Maluku. Many of the remaining dipterocarp forest are dominated by the endemic species Shorea selanica.

Tropical Montane Forests occur in several places in Seram, Mt Rinjani, Lombok, Bacan, Halmahera, Moratai, Buru and Obi, and on other island, but published information on them is extremely scarce. Little aseasonal Montane Forest survives in Nusa Tenggara and Maluku (just 1.9% of north Maluku and 0.2% of southern Maluku); it survives on Ambon Seram and Flores. Seasonal Montane Forests occur above Monsoon Forests. It is more prevalent in Nusa Tenggara and southern Maluku (1.2%) than in Central and Northern Maluku (0.2%). Most of the mountainous areas of Nusa Tenggara must have originally been covered with seasonal Montane Forest (Collins et al. 1991). In some areas the gum tree (Eucalyptus urophylla) dominates these forests and many such forests are being cleared, but some fragments still exist on Timor (van Steenis 1972) .Timor Mountains are the driest in the region, if not the whole of Malesia; they are continuously burnt and almost all are degraded to some extent up to their summits.