Niche differentiation among tropical trees : searching for links between phylogeny, ecophysiology and habitat preferences.

Abstract

Niche differentiation is the partitioning of resources by different species where each has a slightly different set of requirements, thereby facilitating species coexistence. Within tropical rainforests, resource heterogeneity shapes the specific habitat requirements of tree species and species have specialization traits to utilize resource availability. This thesis explores the ecophysiology and physiology of Knema and Horsfieldia species (Myristicaceae) relative to light and water gradients via physiological parameters and photosynthetic capacities. The field ecophysiology studies involved field observations of Knema and Horsfieldia trees (Bukit Timah Nature Reserve, Upper Seletar Reservoir and Pulau Ubin) relative to light and water gradients, while greenhouse physiology studies involved subjecting Knema seedlings to differential water gradients to observe stress response and adaptability. Through the combination of field and greenhouse studies, our understanding of habitat preferences and ecological niches of Myristicaceae tree species can be refined. Physiological traits could also be mapped onto a simplified phylogeny of Knema in an attempt to detect phylogenetic signals related to niche differentiation in the family.