................................................................................................................................................................................ 6 Chapter 1: Introduction ............................................................................................................................................ 10 1.1 General Background and Context of Study ........................................................................................ 10 1.2 Overview of Cycads ......................................................................................................................................... 11 1.3 The South African Species of Encephalartos .................................................................................... 12 1.4 Project Aims ....................................................................................................................................................... 13 1.5 Project Objectives............................................................................................................................................ 14 Chapter 2: Life history traits as a basis for grouping cycads species .............................................. 15 2.1: Introduction ...................................................................................................................................................... 15 2.1.1 Life History Traits in context ........................................................................................................... 15 2.1.2 Background to Life History Theory .............................................................................................. 15 2.1.3 Life history theory in Ecology .......................................................................................................... 18 2.1.4 Factors affecting life history traits ................................................................................................ 20 2.1.5 Overview of functional response types and cycad applications ................................... 20 2.2 Methods ................................................................................................................................................................. 23 2.2.1 Compiling the species trait matrix ................................................................................................ 23 2.2.2 Statistical Analyses of trait matrix to find groups ................................................................ 25 2.3 Results ................................................................................................................................................................... 29 2.3.1 Identifying Groups based on life history traits ...................................................................... 29 2.3.2 Phylogenetic signal ................................................................................................................................ 37 2.3.3 Association with environmental variables .............................................................................. 39 2.4 Discussion ............................................................................................................................................................ 41 2.4.1 Overview ...................................................................................................................................................... 41 2.4.2 Group Distinction ................................................................................................................................... 42 2.4.3 Phylogenetic signal in the life history types ............................................................................ 44 2.4.4 Association of Groups with the Environment ......................................................................... 45 2.4.5 Conclusion .................................................................................................................................................. 48 Chapter 3: The population structure and Survivorship of South African cycads as an emergent property of their life history traits .............................................................................................. 50 3.