SYSTEMATIC REVISION OF PTERIS L. IN TROPICAL AFRICA AND ECOLOGY OF FERNS AND LYCOPHYTES IN LOWLAND TROPICAL RAINFORESTS Dissertation Zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaft des Fachbereich 3: Mathematik/Naturwissenschaften der Universität Koblenz-Landau Germany October 2012 Peris Wangari Kamau Referent: Prof. Dr. Eberhard Fischer Korreferent: Prof. Dr. Maximilian Weigend SYSTEMATIC REVISION OF PTERIS L. IN TROPICAL AFRICA AND ECOLOGY OF FERNS AND LYCOPHYTES IN LOWLAND TROPICAL RAINFORESTS Dissertation Zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaft des Fachbereich 3: Mathematik/Naturwissenschaften der Universität Koblenz-Landau Germany October 2012 Peris Wangari Kamau Referent: Prof. Dr. Eberhard Fischer Korreferent: Prof. Dr. Maximilian Weigend ii TABLE OF CONTENTS TABLE OF CONTENTS .................................................................................................... III LIST OF FIGURES ............................................................................................................. VI LIST OF TABLES .............................................................................................................. VII LIST OF ACRONYMS ..................................................................................................... VIII SUMMARY .......................................................................................................................... IX CHAPTER 1. GENERAL INTRODUCTION ...................................................................... 1 1.1 Study objectives............................................................................................................. 11 1.2 Research hypotheses ..................................................................................................... 11 CHAPTER 2. TAXONOMIC SURVEY OF THE GENUS PTERIS .................................. 12 2.1 History and conspectus of Pteris in Africa ................................................................... 12 CHAPTER 3. METHODOLOGY ........................................................................................ 17 3.1 Morphological studies................................................................................................... 17 3.1.1 Phenetics ................................................................................................................................ 17 3.1.2 Phylogeny ............................................................................................................................... 21 3.1.3 Conservation .......................................................................................................................... 24 CHAPTER 4. RESULTS ...................................................................................................... 26 4.1 Morphology ................................................................................................................... 26 4.1.1 Rhizome ................................................................................................................................. 26 4.1.2 Frond ...................................................................................................................................... 26 4.1.3 Stipe ........................................................................................................................................ 27 4.1.4 Lamina .................................................................................................................................... 28 4.1.5 Lobe apices ............................................................................................................................ 28 4.1.6 Indumentum .......................................................................................................................... 28 4.1.7 Venation ................................................................................................................................. 29 4.1.8 Sori .......................................................................................................................................... 29 4.2 Cytology ........................................................................................................................ 29 4.3 Phenetic analysis ........................................................................................................... 30 4.4 Phylogenetic analysis .................................................................................................... 32 iii CHAPTER 5. DISCUSSION AND CONCLUSIONS ......................................................... 36 5.1 Phenetic observations ................................................................................................... 36 5.2 Phylogenetic relationships ............................................................................................ 38 5.3 Conclusion and recommendations ............................................................................... 39 5.4 Systematic treatment of Pteris of tropical Africa .......................................................... 41 CHAPTER 6. ECOLOGY OF FERNS AND LYCOPHYTES IN TROPICAL LOWLAND RAINFORESTS OF KAKAMEGA AND BUDONGO ........................................................ 73 6.1 Introduction .................................................................................................................. 73 6.1.1 Patterns of ferns and lycophytes richness in African countries ........................................ 74 6.1.2 Ferns as indicators of ecosystem health .............................................................................. 77 6.1.3 Research questions and hypothesis ...................................................................................... 78 6.2 Study Areas .................................................................................................................... 79 6.2.1 Kakamega Forest ................................................................................................................... 79 6.2.2 Budongo Forest ..................................................................................................................... 83 6.3 Field sampling .............................................................................................................. 85 6.4 Data analysis ................................................................................................................. 87 6.4.1 Sampling effort and species estimation ............................................................................... 87 6.4.2 Beta-diversity ......................................................................................................................... 87 6.5 Results ........................................................................................................................... 89 6.5.1 Estimation of species richness and sampling effort ........................................................... 89 6.5.2 Community Structure ............................................................................................................ 91 6.5.3 Species richness and occurrences in Kakamega and Budongo forests ............................. 93 6.5.4 Species distribution and diversity in different study sites .................................................. 95 6.5.4.1 Richness and β-diversity .............................................................................................. 95 6.5.4.2 Floristic dissimilarity estimates in Kakamega and Budongo forests ........................ 97 6.5.5 Taxonomic composition ....................................................................................................... 99 6.5.6 Life form composition .......................................................................................................... 99 6.6 Discussion ................................................................................................................... 102 6.6.1 Sampling effort and species estimation ............................................................................. 102 6.6.2 Diversity patterns ................................................................................................................ 105 6.6.3 Species richness and distribution of diversity ................................................................... 106 6.6.4 Taxonomic composition ..................................................................................................... 111 6.6.5 Life-form composition........................................................................................................ 112 6.6.5.1 Terrestrial species....................................................................................................... 112 6.6.5.2 Epiphytic ferns ........................................................................................................... 113 6.6.5.3 Lithophytes ................................................................................................................. 117 6.6.6 Environmental factors and fern species richness in Kakamega and Budongo forests.. 117 6.6.7 Ferns as bioindicators of forest conditions ....................................................................... 119 6.6.7.1 Ferns of disturbed sites ............................................................................................. 120 6.6.7.2 Riverine fern species .................................................................................................