Altitudinal zonation of climate and vegetation in a global megadiversity centre, Mount Kinabalu (North Borneo)

Abstract

In the context of the long term project Changing Biodiversity (Biodiversität im Wandel) of the Academy of Sciences and Literature (Mainz) a study trip to Sabah (North Borneo) was conducted. The aim of the trip was to explore the possibilities of establishing a research project on the distribution and ecology of epiphytic angiosperm plants in the primary forests surrounding Mount Kinabalu. Topo-climatic studies on the hygrothermal altitudinal zonation of Mount Kinabalu should be included in the project. Because the lowland rain forest of the foothills of Mount Kinabalu have to a large degree been degraded and converted to agricultural lands, three well-preserved forest reserves (Sepilok near Sandakan, Danum Valley near Lahad Datu and the Crocker Range near Kota Kinabalu) were selected in order to gain some insight into the Dipterocarpaceae-dominated lowland rain forests of Borneo. Additionally, certain islands off the western and eastern coasts of Sabah (Tungku Abdul Rahman National Park and Turtle Island respectively) were visited in order to assess the possibilities of comparing the epiphyte vegetation of the mainland forests with that of the outlying islands. Observations concerning the altitudinal zonation of the vegetation and measurements of the soil temperature allowed an integration of the vegetational zones into the hygrothermal altitudinal zonation of the Kinabalu Mountain massive. In contrast to montane forests, the lowland forests on the Sabah mainland are relatively poor in epiphytes. A possible reason could be the regular occurrence of ENSO events which in South-East Asia have been identified as one of the main causes of changes in the flowering phenology of forest trees and even for the immense species richness of the Mount Kinabalu.