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Durham E-Theses Frugivory and seed dispersal by carnivores in the Rhodopi mountains of northern Greece Giannakos, Panayiotis How to cite: Giannakos, Panayiotis (1997) Frugivory and seed dispersal by carnivores in the Rhodopi mountains of northern Greece, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/4900/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 FRUGIVORY AND SEED DISPERSAL BY CARNIVORES IN THE RHODOPI MOUNTAINS OF NORTHERN GREECE by Panayiotis Giannakos B.Sc. M.Sc. The copyright of this thesis rests with the author. No quotation from it should be published without the written consent of the author and information derived from it should be acknowledged. Being a thesis submitted for the degree of Doctor of Philosophy of The University of Durham Department of Biological Sciences 1997 2 JUL isgg ABSTRACT The frugivory and seed dispersal by carnivores were studied using a combination of vegetation surveys, fruit production counts and analysis of faeces distribution and content. The study site is situated close to the Greek-Bulgarian border within a protected area. The habitat comprises of a mixed forest of beech, pine, oak and spruce which is occasionally interrupted by patches of fruiting trees. Faecal samples were collected on five permanent transects which were sampled monthly between May and October of 1993 and 1994. Fruiting plant density was found to be sUghtly higher in the forest than along forest roads, however the species diversity was much higher on the latter. In some cases, immature fruiting plants were found on transects with no mature plants in the vicinity. Availability of ripe fruit was found to increase steadily between May and September. There was a significant difference between the numbers of faeces deposited by the carnivores, with fox being the most numerous, followed by marten, bear and wolf. There was spatial and temporal variation in the number of faeces deposited. Nevertheless, there was no variation between different altitudinal zones. Martens were found to defecate more often on stones when compared with the other carnivores. The analysis of fruit consumption revealed that bears were the most frugivorous carnivores followed by foxes, wolves and martens on the basis of frequency of consumption. The temporal availability of each ripe fruit species coincided with their consumption by the carnivores in most of the cases. A number of seed species were deposited at altitudes where the plants do not normally grow. Foxes dispersed the highest numbers of seeds in the study area and bears were second as they deposited large-size faeces which contained many seeds. Of the dispersed seeds, those of Rubus sp., Rosa sp. and Fragaria vesca were deposited in the highest numbers. Only a smaU number fraction of seeds were damaged through handling by carnivores. DECLARATION I declare that this thesis is original. Any material which is not my own work has been identified as such. The analysis and interpretation of the results are entirely my own unless otherwise stated. No part of it has been submitted previously for a degree at any other university. Copyright The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information from it should be acknowledged. Panayiotis Giannakos Durham 1997 .and the cubs are born at around the time that they (the bears) den. During this time the bears of both sexes become very fat." "Stories about the animals" Aristotle To my parents TABLE OF CONTENTS TABLE OF CONTENTS 1 LIST OF TABLES VI LIST OF FIGURES VIIH ACKNOWLEDGEMENTS IX CHAPTER ONE 1.0. INTRODUCTION TO SEED DISPERSAL 1 1.1. Function of seed dispersal 1 1.1.1. Coevolution and seed dispersal 4 1.1.2. Fruit adaptations to enhance seed dispersal 5 1.2. Quality and quantity component of seed dispersal 11 1.3. Comparison of avian versus mammalian seed dispersers 12 1.3.1. MammaUan legitimate dispersers 21 1.4. Aims of the study and structure of the thesis 26 CHAPTER TWO THE STUDY AREA AND ITS VEGETATION 28 2.1. INTRODUCTION 28 2.1.1. General description of the Rhodope massif and the research area 28 2.1.2. Choice of transects 34 2.2. METHODS AND MATERIALS 38 2.3. RESULTS 40 2.3.1. Vegetation surveys 40 2.3.2. Fruit production 47 2.4. DISCUSSION 51 CHAPTER THREE TEMPORAL AND SPATIAL DISTRIBUTION OF SEED DEPOSITION BY CARNIVORES 57 3.1. INTRODUCTION 57 I 3.1.1. Carnivores 57 3.1.1.1. Home ranges and territoriaUty 57 3.1.1.2. Movements 63 3.1.1.3. The role of faeces in territorial marking by carnivores 63 3.1.2. Brown bear {Ursus arctos) 64 3.1.2.1. Habitat requirements and preferences 64 3.1.2.2. Home ranges and territoriality 65 3.1.2.3. Movements 66 3.1.3. Red fox {Vulpes vulpes) 68 3.1.3.1. Habitat requirements and preferences 68 3.1.3.2. Home ranges and territoriality 68 3.1.3.3. Movements 69 3.1.4. Grey wolf (Canis lupus) 70 3.1.4.1. Habitat requirements and preferences 70 3.1.4.2. Home ranges and territoriality 71 3.1.4.3. Movements 73 3.1.5. Stone marten {Martes martes) 73 3.1.5.1. Habitat requirements and preferences 73 3.1.5.2. Home ranges and territoriality 76 3.1.5.3. Movements 77 3.1.6. Summary 77 3.2 METHODS AND MATERIALS 79 3.2.1. Data recorded 80 3.3 RESULTS 81 3.3.1. The temporal distribution of faeces along the five transects 81 3.3.2. The distribution of faeces in relation to altitude 87 3.3.3 Deposition of faeces on different substrates 87 3.3.4 Deposition of faeces within the plant communities of the study area 88 3.4 DISCUSSION 89 3.4.1. The distribution of the faeces along the five transects 89 3.4.1.1. Estimated numbers of carnivores 93 3.4.2. The distribution of faeces and the seasonal changes 94 II 3.4.3. The distribution of the faeces in relation to the altitude 96 3.4.4. Deposition of faeces on different substrates 97 3.4.5. Deposition of faeces within the plant communities of the study area 98 CHAPTER FOUR THE IMPORTANCE OF FRUGIVORY IN THE DIET OF THE CARNIVORES 100 4.1. INTRODUCTION 100 4.1.1. Brown bear 103 4.1.2. Red fox 109 4.1.3. Grey wolf 113 4.1.4. Stone marten 115 4.1.5. Summary 120 4.1.6. Aims 121 4.2. METHODS AND MATERIALS 122 4.3. RESULTS 124 4.3.1. Species of seed found in faeces 124 4.3.1.1. Factors affecting the frugivory index 124 4.3.1.2. Factors affecting the presence of seed species in faeces 125 4.3.1.3. Frequency of occurrence of the different seed species in faeces 131 4.3.1.4. Number of seed species found in faecal samples 136 4.3.1.5. Combinations of seed species found in faeces 137 4.3.1.6. Occurrence of seed species in the altitudinal zones 138 4.3.2. Numbers of seeds found in faeces 138 4.3.2.1. Factors affecting the number of seeds found in faeces 138 4.3.2.2. Factors affecting the numbers of damaged seeds in the faeces 145 4.3.2.3. The Relationship between seed weight and seed number 148 4.4. DISCUSSION 150 4.4.1. Frugivory index 150 4.4.2. Presence of seed species in the faeces 152 4.4.2.1. Number of seed species found 156 4.4.2.2. Combinations of seed species found in faeces 156 III 4.4.2.3. Frequency of appearance of the seed species and species diversity in the altitudinal zones 158 4.4.3. Numbers of seeds found in faeces 158 4.4.3.1. The effect of carnivores 158 4.4.3.2. Number of seeds found 159 4.4.3.3. Factors affecting the numbers of damaged seeds in faeces 160 4.4.4. Summary 161 CHAPTER FIVE 5.0. GENERAL DISCUSSION 162 5.1. Quantity of seed dispersal 162 5.1.1. Size of the seed bank and fruiting plant density 163 5.2. Quahty of seed dispersal 164 5.2.1. Dispersal distances 166 5.2.2. Propagation of seeds on the transects 167 5.2.3. Post-dispersal seed and seedUng survival 170 5.2.3.1. Factors affecting the regeneration of the fruiting species 173 5.3. Which are the more important dispersers: Birds or mammals 176 5.3.1. Timing of fruit ripening 185 5.3.2. Choice of fruit by frugivores 186 5.4. Conclusion 187 APPENDIX 1 189 COMMON AND LATIN NAMES OF ANIMALS AND PLANTS 1.