Predictive modelling of the distribution of two critically endangered Dipterocarp trees: Implications for conservation of riparian forests in Borneo

Riparian forests of Malaysian Borneo exhibit high tree species diversity. However, many of the tree species found in these riparian forests are conservation dependant, with their current conservation status (sensu IUCN Red List) varying from vulnerable to critically endangered. The present study had two objectives. Firstly, to identify the environmental factors associated with the distribution of two critically endangered tree species, Shorea johorensis and Shorea inappendiculata using a small number of occurrence records. Secondly, the research seeks to predict suitable habitat and distribution of these two species. The occurrence data and environmental variables are incorporated within a maximum entropy (MaxEnt) model to predict the distribution of the species and identify the environmental variables that influence the distribution. The research shows that for a small study area, the bioclimatic variables are relatively insignificant while factors such as, land use, tree cover play a prominent role in determining distribution of tree species.