Negative Effects of Logging on Bird Dispersed Plants in Northern Papuan Lowland Forest, Indonesia

Abstract

Many plants in New Guinean rainforest have relatively larger fruits than those in other tropical forests and may depend on large animal dispersers, but little is known about the impacts of forest disturbance, especially logging, on the species composition and abundance of these trees. In order to provide a baseline for the understanding of their vulnerability, we counted fruiting plants and measured habitat parameters in primary and human-altered habitats in the little studied lowland forest of northern Papua, Indonesia. During the surveys coinciding with peak fruit season, eighty-nine species were recorded in fruit, with 71 species in 24 families known to be consumed by birds, and most of them (97%) were trees. The diversity of bird-consumed fruiting plants differed among the habitat types and was highest in undisturbed primary forest and hunted primary forest. Secondary forests still had a high number of species and individuals but were dominated by light demanding plants and a low number of uniquely found species. Logged forest and agricultural habitats showed only a low abundance of bird-consumed fruiting plants, being about 2-3 times lower than in primary forests. Plants with large sized fruits (diam. > 20 mm) were mainly found in primary forests, confirming their importance for maintaining interactions between large frugivorous birds and plants that are of relevance for forest regeneration.