Population status of the critically endangered tree Vatica venulosa (Dipterocarpaceae) in lowland riparian forests of East Kalimantan

Abstract

Vatica venulosa is a threatened tree from the family Dipterocarpaceae. Due to degradation and conversion of its habitat in lowland riparian forests, this species is classified as Critically Endangered by the International Union for Conservation of Nature (IUCN) Red List. We carried out surveys for V. venulosa in Kutai Kartanegara, East Kalimantan, to depict the current population status of the species in the region. We surveyed 14 forested areas along Belayan River in Kutai Kartanegara. From these 14 locations, we only successfully identified V. venulosa at one location, namely in Long Beleh Village, Kembang Janggut District. A total of 71 individuals of which 84.5% classified in the 0-5 cm diameter class, were found. We also found nine individuals in the mature stage, i.e., producing flowers and fruits. The main threat to V. venulosa is habitat conversion into large-scale oil palm plantations. Protection of the forest fragment in Long Beleh is highly recommended in order to protect the species from local extinction.