Biologists investigate consequences of deforestation on large fruit eating bird and seed dispersal in New Guinea
The northern cassowary Casuarius unappendiculatus is the largest bird of New Guinea and a primary seed disperser. Many forest trees in the rainforests of the island have relatively large fruits and seeds compared to those elsewhere, indicating the importance of these birds with their large gape. Since New Guinea lacks large-bodied fruit eating mammals their disappearance would affect the viability of forest trees that rely on these frugivores to disperse their seeds. In turn, because cassowaries depend on the fruits, loss of food plant species may lead to their extirpation.
A large-scale field study conducted by an international research group of University of Göttingen and Universitas Cenderawasih Papua, Indonesia, is studying effects of habitat alteration, changes in food availability and increased hunting pressure on cassowaries in Papua, Indonesia. Recently published results suggest that the birds might be moderately tolerant of intermediate disturbance but are certainly intolerant of heavy disturbance such as intensive logging. The study was published in the journal Oryx – the International Journal of Conservation.
“Logging has become the major threat to the population of cassowaries in New Guinea, because unsustainable logging practices can destroy forest canopy and reduce habitat quality, especially if food plants are removed,” says Dr. Margaretha Pangau-Adam. Furthermore, the sparse canopy cover in heavily disturbed forest increases the amount of heat (infrared) radiation reaching the forest floor, causing the disappearance of water sources that are critical. Such effects may be exacerbated by hunting, which is facilitated by increased access to forest from logging roads.
“To secure populations of northern cassowary and of other large animal species in Indonesia’s Papua province, forest degradation needs to be addressed by enforcing regulations in existing protection forest. But we also need to establish new protected areas, such as wildlife reserves, since existing ones are not large enough,” says Dr. Matthias Waltert, senior scientist at University of Göttingen and co-author of the study. Dr. Margaretha Pangau-Adam holds a Dorothea Schlözer Postdoctoral Fellowship at the University of Göttingen.
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