Orangutan Population Density Analysis


A Critical Study of Orangutan Population Viability Analyses

This report describes and evaluates work carried out with The Orangutan Tropical Peatland Research Project (OuTrop) in the summer of 2003 in the Sebangau catchment peat swamp forests of Central Kalimantan, Indonesia. It provides an up-to-date summary of the work which has been carried out recently aiming to protect the Orangutan and will discuss current threats to the increasingly endangered primate.

It will compare and contrast data collection methods for Orangutan Population Viability Analysis (PVA) – using data collected with the traditional line transect method and comparing this to what will be called plot transect data. Although it is shown line transect methods give an underestimation of population, due to constraints in time and budget they are still believed to be the best method of data collection.

This paper arrives at a correction factor of 1.55 that can be used for analysis of future data collected and based on this study provides the latest population estimate for the Orangutan of the Sebangau catchment at 8,708 individuals – an increase of over 3000 compared to previous estimates using line transect methods alone.

Finally this paper will discusses some of the wider issues of concern in conservation biology today, using a quote from Wilson’s 1988 seminal text “The Diversity of Life” to query questions of focus, immediacy and future management of the Orangutan.


This thesis was submitted as part fufillment of the MA(SocSci) Hons in Geography in the Department of Geography & Geomatics at the University of Glasgow.