Patterns of abundance and diversity in epiphytic orchids on Parashorea malaanonan trees in Danum Valley, Sabah

Abstract

Research in forest canopies has been restricted by access difficulties for a long time, however in the last 20 years techniques to provide access into tree canopies have been developed, now opening a field of biology to more scientists. This study uses rope techniques for accessing the canopy in a primary rainforest system in Borneo, Malaysia, to study the occurrence and patterns of orchid distribution in Parashorea malaanonan dipterocarp trees. Five trees were sampled, a total of 42 orchids from 8 genera were present. Data on branch height, distance from bole, position of the orchid on branch, substrate and associations were recorded and then analysed to find any noteworthy interactions. Significant relationships were found between many of the variables. Branch height was found to correlate with substrate, association, genera, species and position on branch, implying that it is a major contributor to orchid variation. Substrate showed a relationship with both genera and species, and non-uniform distribution across the five trees sampled. Association and position on branch were found to have an inverse relationship, as were genera and tree. However, this study could not establish definitive reasons for the relationships between variables and patterns in orchid diversity and abundance.