Ecology of the Sitatunga (Tragelaphus spekei selousi Rothschild, 1898.) in the Bangweulu swamps, Zambia, Central Africa. by Ian Patrick Alexander Manning 'i B.Sc., Acadia University, 1970 Thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in the Department of Biology at Acadia University Spring, 1983 -iv- TABLE OF CONTENTS Page LIST OF TABLES ix LIST OF FIGURES X LIST OF PLATES xii ABSTRACT xiii INTRODUCTION 1 OBJECTIVES 2 THE BANGWEULU BASIN 4 Structure and Geology 5 Topography and Soils 6 Rainfall and Hydrology 7 The Study Areas 8 Vegetation 9 Burning 10 Termites and Levees 11 THE STUDY AREA 11 Study Area 2 11 Study Area 3 12 Study Area 1 14 MAN 15 Historical Perspectives 15 The Population 15 The Lukulu Estuary 16 Chiundaponde and Study Area 1 16 -v- TABLE OF CONTENTS (Cont'd.) Hunting 17 Conservation and Protection 17 THE WILDLIFE 18 Historical Perspectives 18 Principal Species of the Bangweulu 18 THE SITATUNGA 21 Taxonomy 21 The Tribe Tragelaphini 22 Distribution and Status 24 Sitatunga Literature Review 26 MATERIALS AND METHODS 28 Capture 28 Equipment and Techniques 28 Tranquillization 29 Shot Sample 29 Examinations and Measurements 29 Physical Measurements 29 Marking 33 Age Determination 34 Reproduction ' 3 6 Foetal Growth 36 Field Sex and Age Classification 37 Observations 39 Growth 39 RESULTS AND DISCUSSION 40 PHYSICAL CHARACTERISTICS 40 -vi- TABLE OF CONTENTS (Cont'd.) Pelage 41 Horns 41 Hooves 43 TRANQUILLIZATION 45 POPULATION PARAMETERS 47 Sex and Age Classification 47 Field Criteria Composition 47 Relative Age and Sex Composition 51 Age Determination 51 Growth 55 Body Condition 59 Reproduction . 59 Conception 62 Gestation Period 63 Foetal Growth 64 Parturition Interval 66 Births 66 Sexual Activity 67 Seasonality of Reproduction 67 Parasites and Diseases 72 Capture Mortality and Injuries 72 Predation 73 Population Density 73 MOVEMENTS AND USE OF THE VEGETATION 75 Study Area l 75 -vii- TABLE OF CONTENTS (Cont'd) Study Area 2 76 Study Area 3 76 THE FOOD SUPPLY 78 The Wet Season Food Supply 79 Protein Content Relative to Water Depth 81 BEHAVIOUR . 82 Activity Patterns 82 Aggregations and Social Groupings 82 Study Area 2 82 Study Area 1 83 Study Area 3 84 Influence of Environment on Social Organization. 85 Vegetation Structure 85 Habitat Modification 88 Social Behaviour . 89 Auditory Communication 89 Visual Communication 90 Olfactory Communication 95 Reproductive Behaviour 96 Feeding Behaviour 96 Comfort Behaviour 97 Spatial Behaviour 97 Home Range 97 Territoriality 99 -viii- TABLE OF CONTENTS (Cont'd.) Relationship with other Species 103 Play 103 Competition 104 Lechwe 104 Sitatunga/Predator Space Relations 105 CONSERVATION OF THE SITATUNGA 107 Sitatunga and Man 108 Land-use and Habitat Modification 109 ACKNOWLEDGEMENTS 111 REFERENCES 113 PERSONAL COMMUNICATIONS 119 APPENDICES 121 A. Vegetation types and plant species of the Bangweulu . 121 B. Some common wildlife species of the Bangweulu. 125 C. Relative age determination criteria 126 -ix- LIST OF TABLES Page 1. Field sex and age criteria 38 2. Comparative horn measurements for three populations of sitatunga . 42 3. Comparisons of front hoof length of adult males for three populations of sitatunga . 44 4. Average hoof widths of two sitatunga populations 44 5. Study area 1: sex/age composition (Field criteria) 47 6. Study area 2: sex/age composition (Field criteria) 48 7. Study area 3: sex/age composition (Field criteria) 49 B. A comparison of the sex/age composition (Field criteria) for study area 2 and 3, and for 2 and 3 combined, and for the Saiwa swamp populat~on. so 9. Linear correlations of physical parameters for males . • . 57 10. Linear correlations of physical parameters for females . 57 11. Parturition intervals and time of first parturition at Wroclaw zoo . • 61 12. Ages at first conception, calculated from age at parturition of captive sitatunga . 60 13. Gestation periods quoted for sitatunga 64 14. Foetal ages estimated by the method of Hugget and Widdas (1951) . 66 15. The observed sex and age structure of different group sizes in study area 2 . 86 16. Aggregations of a population of 9 sitatunga in study area 1 observed over three days for 8 hours 87 17. Minimum home ranges of 9 sitatunga in study area 2 . • • . 9 8 -x- LIST OF FIGURES Page 1. Zambia and the study area . 130 2. Study areas 1, 2 and 3, S.E. Bangweulu 131 3. Lukulu estuary study areas 2 and 3 132 4 . Vegetation types within study area 2 133 5. The seasonal occupancy of study area 2 by lechwe 134 6. The distribution of sitatunga 135 7. The distribution of sitatunga in Zambia 136 8 . Horn development in sitatunga . 137 A 137 B 9. Adult male horn shapes • D • • • D D D 0 D D 138 10. The sex and relative age structure in study area 3 139 11. Percentage relative age distribution of the total sampled population (N=l23) ..... 140 12. The sex and relative age distribution of the total sample . • . 141 13. Theoretic quadratic growth in live weight for male sitatunga (n=51) . 142 14. Theoretic quadratic growth in live weight for females (n=68) . 143 15. Horn growth of sitatunga related to relative age 144 16. Conception and parturition peaks in the Bangweulu related to rainfall 145 17. Parturition peaks for sitatunga, two congenerics and two other species found in the Bangweulu . 146 18. Conception distribution peaks for nyala, bush­ buck and sitatunga populations .... 147 19. Sitatunga births in four European zoos 148 -xi- LIST OF FIGURES (Cont'do) 20. Seasonal water occupancy of study area 2 149 21. Captured and observed positions of sitatunga in study area 2 o • 0 150 22. Study area 2: the minimum home range of six adult males 0 0 0 151 23. Study area 2: the minimum home range of three adult females 152 24o Sitatunga marked and then observed or captured at yearly intervals . o o o 153 -xii- LIST OF PLATES Page 1. Sedge marsh in study area 2 with sitatunga calf in middle ground 13 2. Sitatunga adult male 25 3. Shortly before the capture of an adult male in study area 3 30 4. Sitatunga calf in Cyperus digitatus 70 5. The nose chevron of an adult male presented in a threat posture . 92 6. The nose chevron presented in a non-threatening posture 93 -xiii- ABSTRACT Research into the ecology of the sitatunga (Tragelaphus spekei Rothschild, 1898.) in the south-east Bangweulu, Zambia, was carried out between 1973 and 1976. The sex ratio for sita- tunga does not differ significantly from 1:1, although 47.3% of the population are adult females and 25.6% adult males, 12.1% immature males, 4.3% immature females and 10.6% calves. Two conception peaks are related to the onset and cessation of the rains with breeding occurring throughout the year. Sita- tunga occur singly (50%), in twos (22.2%) or in threes (16.7%). Females and their calves are the only group with any integrity. The maximum number observed in a group was 7. The minimum 2 2 home range for males is 0.0363 km and for females 0.176 km . Aggression and the mutual avoidance of dominant males suggests territoriality. Sexual dimorphism is marked. Pelage colour- ation is variable. The white facial markings are important in male agonistic displays. Criteria for relative age determin- ation of sitatunga were derived from eruption and attrition sequences of impressions taken from maxillary teeth. Males reach a theoretical maximum weight of 106 kg at 8.1 years and females 51.5 kg at 7.34 years. Males are 54.6% heavier than females and maximum horn length is achieved at 7.5 years. Age is significantly correlated with weight, horn length and the length/weight index. The mean horn length for adults is 64.2 em and the mean front hoof length, for both sexes, is 7.6 em. The impact of man on sitatunga in the Bangweulu is minimal. -1- INTRODUCTION The sitatunga (Tragelaphus spekei) is a member of the Tragelaphini, a tribe of spiral horned antelope noted for their beauty and shy retiring habits. The species is widely distributed in Africa where suitable wetland occurs. Their importance as a source of protein for subsistence agricul­ turists, and the extreme paucity of knowledge concerning their life history gave impetus to this study. Specifically, I decided that a knowledge of the species habitat requirements, movements and behaviour was a necessary adjunct to Phase 1 of the Black Lechwe Project. This project was a 4 year ecological investigatibn of the black lechwe antelope (Kobus leche smithemani) conducted by Grimsdell and Bell (1975) in the Bangweulu basin of Zambia. The project was administered by my employers, the Department of National Parks and Wildlife. I carried out this research, in addition to other research and conservation duties, be­ tween May 1973 and February 1976, in the south-east Bangweulu. (Figure 1) • -2- OBJECTIVES 1. To classify the main vegetation types within the sitatunga's habitat. 2. To describe their habitat requirements. 3. To capture, examine and mark a large sample of sitatunga. 4. To define age criteria from the eruption and attrition of maxillary teeth. 5. To describe the general morphology of the subspecies. 6. To compare their morphological features with those of other subspecies. 7. To classify the population with regard to sex and relative age. 8. To assess the sex ratio of the population and that of the different age groups. 9. To derive a theoretical body growth curve for use in the field. 10. To assess which physical parameters are closely corre­ lated with age. 11. To define the breeding peaks in relation to environ­ mental factors.