Pelahlar (Dipterocarpus littoralis)

Mohamed bin Zayed Species project number 11251915

 In comparison to those in continents, plants in island ecosystems are more sensitive to the threats due to small population sizes and ranges as well as their unique characteristics resulting from prolonged evolutionary isolation (Frankham 1998). According to Sax and Gaines (2008), out of 80 plant species that became extinct in the last 400 years 50 were island species.

The giant tree Dipterocarpus littoralis, an endemic plant species in Java, is restricted only to Nusakambangan Island in Central Java (Ashton 1998). Predicted to have a distribution range of 80 km2, it has been categorized as critically endangered by IUCN since 1997 (Walter and Gillett 1998) and included nationally on list of priority species for 2008-2018 Indonesia conservation action (Minister of Forestry Decree P.57/Menhut-II/2008).

Walter and Gillett (1998) stated that illegal logging is a major threat to this species.The trees are illegally harvested despite the presence of two nature reserves and four high-security prisons in the island. Partomiharjo and Prawiroatmojo (2001) found only three individuals with trunk circumference greater than 100 cm during their botanical exploration across the Island.

To develop comprehensive conservation action for threatened species, basic information on population size and range as well as habitat requirement of the species is needed (e.g. Kozlowski & Matthies 2009; Ren et al. 2010). Concerning D. littoralis, no detailed ecological studies have been conducted.

In this project, population status and habitat preferences of D. littoralis in West Nusakambangan Nature Reserve will be assessed. The objective is to measure the distribution, population size and structure as well as environmental conditions that influence the presence and density of D. littoralis.