Plant Communities, Species Diversity, Seedling Bank and Resprouting in Nandi Forests, Kenya Dissertation Zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaft Fachbereich 3: Mathematik/Naturwissenschaften Universität Koblenz-Landau Vorgelegt am 16. September 2011 von Adane Girma Gebreselasse geb. am 27 Oktober 1974 in Äthiopien Referent: Prof. Dr. Eberhard Fischer Korreferent: Prof. Dr. Wilhelm Barthlott This work is dedicated To my father Ato Girma Gebreselass (1937-2004) My mother Woizero Yeshi Kidanewold My wife Enat Ashine My brothers and sisters and To all Ethiopian peasants who did not enjoy formal education but toiled hard to send their children to school hoping that their offsprings will be better off. Table of Contents List of Tables .......................................................................................................................... VI List of Figures ....................................................................................................................... VIII Abstract ..................................................................................................................................... X 1. General Introduction ...............................................................................................................1 1.1 Tropical Rain Forest .............................................................................................................1 1.2 Biodiversity ..........................................................................................................................3 1.2.1 Species diversity ................................................................................................................4 1.2.2 Species richness .................................................................................................................5 1.3 Deforestation and Fragmentation of Tropical Forests ............................................................6 1.3.1 Deforestation .....................................................................................................................6 1.3.2 Fragmentation ....................................................................................................................8 1.4 Natural regeneration ........................................................................................................... 10 1.4.1 Factors affecting seedling regeneration ............................................................................ 11 1.4.2 Factors affecting regeneration from stump ....................................................................... 13 1.5. Objective of the study ........................................................................................................ 14 2. Materials and Methods ......................................................................................................... 16 2.1 Study Area .......................................................................................................................... 16 2.1.1 Location and physiography .............................................................................................. 16 2.1.2 Geology and soil .............................................................................................................. 17 2.1.3 Climate ............................................................................................................................ 18 2.1.4 Vegetation and fauna ....................................................................................................... 19 2.1.5 Gazettment detail and administration ............................................................................... 21 2.2 Data Collection ................................................................................................................... 23 2.2.1 Vegetation data ................................................................................................................ 23 2.2.2 Environmental data .......................................................................................................... 25 3. Floristic Composition of Nandi Forest .................................................................................. 26 3.1 Introduction ........................................................................................................................ 26 3.2 Material and Methods ......................................................................................................... 27 3.2.1 Study sites ....................................................................................................................... 27 3.2.2 Vegetation sampling ........................................................................................................ 27 3.2.3 Diversity analysis ............................................................................................................ 27 3.2.4 Cluster analysis ................................................................................................................ 34 3.2.5 Ordination ....................................................................................................................... 36 3.3 Results ................................................................................................................................ 38 3.3.1 Floristic composition ....................................................................................................... 38 III 3.3.2 Alpha and beta diversity .................................................................................................. 40 3.3.3 Species accumulation curve ............................................................................................. 42 3.3.4 Species richness estimation .............................................................................................. 43 3.3.5 Floristic similarities ......................................................................................................... 44 3.3.6 Plant communities ........................................................................................................... 44 3.3.7 Ordination ....................................................................................................................... 50 3.4 Discussion .......................................................................................................................... 52 3.4.1. Floristic composition ...................................................................................................... 52 3.4.2 Alpha and beta diversity .................................................................................................. 54 3.4.3 Species accumulation curve and species richness estimation ............................................ 56 3.4.4 Plant communities ........................................................................................................... 58 3.4.5 Description of east African mountain forests .................................................................... 61 4. Population Structure of Nandi Forest .................................................................................... 63 4.1 Introduction ........................................................................................................................ 63 4.2 Material and Methods ......................................................................................................... 64 4.2.1 Study sites ....................................................................................................................... 64 4.2.2 Data collection and analysis ............................................................................................. 64 4.3 Results ................................................................................................................................ 66 4.3.1 Growth forms .................................................................................................................. 66 4.3.2 Height class distribution................................................................................................... 67 4.3.3 Diameter class distribution ............................................................................................... 68 4.3.4 Basal area and abundance ................................................................................................ 72 4.4 Discussion .......................................................................................................................... 75 5. Seedling Bank and Resprouting in Nandi Forests .................................................................. 79 5.1 Introduction ........................................................................................................................ 79 5.2 Material and Methods ......................................................................................................... 80 5.2.1 Study sites ....................................................................................................................... 80 5.2.2 Data collection and analysis ............................................................................................. 80 5.3 Results ................................................................................................................................ 82 5.3.1 Seedling bank .................................................................................................................. 82 5.3.2 Regeneration from stumps ..............................................................................................