THE STATUS OF FOREST BIODIVERSITY IN OCEANIA

Abstract

Within Oceania, a distinction is drawn between the older, continental land masses of Australia, New Guinea, New Caledonia and New Zealand, and the geologically younger islands and island arcs of the Pacific. As a rule, the former show high species richness and high levels of endemism, while the latter show a west to east decline in species richness and endemism, culminating in the impoverished pantropical biota of the oceanic islands. Within continental areas such as Australia, species richness can be related to latitude and altitude (as temperature gradients), rainfall, and soil fertility. Within the Pacific region, differences in species richness between islands or island groups can, in addition, be related to age, isolation, and habitat diversity. The small and often disharmonic biotas of the islands are vulnerable to disturbance and invasion by exotic species, which in places pose severe threats to the native species.