Rainforests are the worlds treasure houses of biodiversity, but all rainforests are not the same. Biodiversity may be more evenly distributed in some forests than in others and, therefore, may require different management and preservation strategies. That is one of the conclusions of a large-scale Smithsonian study of a lowland rainforest in New Guinea, published in the Aug. 9 issue of the journal Nature.
Most previous research has focused on diversity hot spots, such as upland rainforests in the foothills of the Andes, where steep gradients in elevation, temperature, rainfall and other environmental factors boost diversity by creating diverse habitats within a short distance. Such change in a regions species makeup between sites is called beta diversity: some rainforests have steep environmental gradients and high beta diversity.
A large proportion of the worlds remaining rainforests are lowland forests in New Guinea, Borneo and the Congo and Amazon Basins. Many researchers have speculated that such lowland rainforests also would have high beta diversity, but this has not been rigorously tested. Little data exists for species distributions in these vast forests, particularly for insects, which make up a large share of the worlds biodiversity.
An international group of entomologists and botanists, including Smithsonian researchers, has assembled data representing 500 species of caterpillars, ambrosia beetles and fruit flies in the undisturbed lowland rainforest of the Sepik and Ramu river basins in Papua New Guinea. The team collected insects and plants from eight study sites across 75,000 square kilometers of contiguous forestan area the size of South Carolinaand noted the variation in species makeup among the different sites.
The data showed low beta diversity across the study area for all three groups of insects as well as for plants, indicating that species tend to be widespread and the biological communities change
Contact: Carolyn Martin