Ecology and Utilisation of Harpagophytum procumbens (Devil's Claw) in Southern Africa

Transcription

1 Ecology and Utilisation of Harpagophytum procumbens (Devil's Claw) in Southern Africa Plant Species Conservation Monographs 2 Results of the R+D Project Berit Hachfeld Federal Agency for Nature Conservation Bonn - Bad Godesberg 2003

2 Content List of Figures 9 List of Tables 11 Abbreviations 13 Acknowledgements 14 Preface 15 1 Introduction - Biodiversity and medicinal plants 17 2 Aim of the study & research objectives 20 3 Systematics of Harpagophytum Taxonomy and evolution Scientific and common names 25 4 Distribution of Harpagophytum Distribution in southern Africa Distribution in National Parks 28 5 The natural environment of Harpagophytum Physiography Climatic conditions Precipitation Namibia South Africa Air temperature and relative air humidity Climatic regions Habitat requirements of Harpagophytum Namibia South Africa Vegetation Namibia Biome classification Vegetation types South Africa Biome classification 35 6 The socio-economy of Harpagophytum 36 7 The drug Harpagophyti radix Harpagophytum in Pharmacopoeias Constituents of Harpagophytum Constituents of Harpagophytum procumbens Constituents of Harpagophytum zevheri Therapeutical effects of Harpagophvtum Medicinal applications 40

3 7.3.2 Traditional uses Adulterations and confusion with other species 40 8 Ecology of Harpagophytum Approach Methods Field campaigns The research sites The documentation sheet Applied analytical methods Research areas Regions and districts Occurrence and frequency of Harpagophytum Occurrence under different land use Occurrence in different vegetation types Namibia South Africa Summary and conclusions on the occurrence of Harpagophytum The impact of the habitat on Harpagophytum Harpagophytum density in different habitat types Namibia South Africa Summary and conclusions on the impact of the habitat on Harpagophytum The impact of soil properties on Harpagophytum Physical soil properties Chemical soil properties Summary and conclusions on the impact of soil properties on Harpagophytum The impact of land use on Harpagophytum Frequency of different grazing intensity classes Resource status and grazing intensity Summary and conclusions on the impact of land use on Harpagophytum The impact of the vegetation on Harpagophytum Role of vegetation layers for the occurrence of Harpagophvtum Grazing intensity and grass cover Grass cover and resource status of Harpagophytum Accompanying plant species Summary and conclusions on the impact of the vegetation on Harpagophytum Spatial distribution of Harpagophytum Resource distribution on the square kilometre Analysis of variance in the spatial distribution of Harpagophytum Summary and conclusions on the spatial distribution of Harpagophytum 92

4 8.10 Reproductive effort of Harpagophytum Flowers Background information on flowers of Harpagophvtum Flowering intensity Flowering intensity of single individuals Flowering intensity of Harpagophytum in various vegetation types Impact of plant size on flowering intensity Summary on the flowering of Harpagophvtum Fruit set Background information on fruits, fruit-set and dispersal of Harpagophytum Intensity of fruit-set of Harpagophytum Fruit-set of various vegetation types Summary on the fruit set of Harpagophvtum Seed bank Background information on seeds, seed bank and germination of Harpagophytum Calculation of the potential seed bank of Harpagophytum Seed bank contribution in various vegetation types Ill Summary on the seed bank of Harpagophytum Reproductive effort of different Harpagophytum densities Summary and conclusions on the reproductive effort of Harpagophytum Utilisation of Harpagophytum Density of harvested sites Intensity of utilisation Frequency of harvesting holes and Harpagophytum plants Utilisation intensity in comparison to potential resource availability Utilisation intensity in regions and provinces Impact of harvesting on the density of Harpagophytum Analysis of variance in the utilisation of Harpagophvtum Summary and conclusions on the utilisation of Harpagophytum Discussion and conclusions on the ecology of Harpagophytum Resource availability of Harpagophytum Reproductive effort of Harpagophytum Utilisation of Harpagophytum Regeneration potential Re-documentation of Harpagophytum Approach Methods Field campaigns Methods of re-documentation Research areas One-year re-documentation of Harpagophytum Results 149

5 Changes in Harpagophytum quantities on re-documentation sites Utilisation of Harpagophytum on re-documentation sites Environmental conditions on re-documentation sites Reproductive effort of Harpagophytum on re-documentation sites Summary and conclusions on the one-year monitoring of Harpagophytum Three-year re-documentation of Harpagophvtum Results Summary and conclusions on the three-year re-documentation of Harpagophytum I nterviews Approach Methods Research areas Results Frequency and density of Harpagophytum Ecology of Harpagophytum The role of the abiotic environment for the occurrence of Harpagophytum The role of the biotic environment for the occurrence of Harpagophytum The role of land use for the occurrence of Harpagophytum Utilisation and of Harpagophytum Decrease of the resource Harpagophytum Summary and conclusions on the results of the questionnaire Synthesis of field studies in Harpagophytum Environmental conditions of Harpagophytum Impact of land use on Harpagophytum The spatial distribution and abundance of Harpagophytum 1 80 I 1.4 Potential threats of Harpagophytum through harvest 182 I 1.5 Regeneration potential of Harpagophytum 182 I 1.6 Conclusions on the field studies in Harpagophytum Harvesting of Harpagophytum Methods Harvesting Harvesting techniques Sustainability of harvest Yield Further processing Processing steps undertaken by the harvester Concerns regarding processing Quality of harvested material Namibia Harvesting localities Harvesters 194

6 Middlemen Notable operations South Africa Harvesting localities Harvesters Middlemen Notable operations Botswana Harvesting localities Harvesters Middlemen Notable operations Prices for raw material of Harpagophytum Prices paid to the harvesters Prices paid to the middleman Prices paid to the exporter Prices paid for retail products Summary and conclusions on the harvesting of Harpagophytum Cultivation and vegetative propagation of Harpagophytum Cultivation trials Quantity of Harpagophytum produced by cultivation Possible impacts of cultivation Trade in Harpagophytum Methods Namibia Export quantities Exporting companies Countries of destination South Africa Export quantities Exporting companies Countries of destination Botswana Export quantities Exporting companies Countries of destination The market situation Europe USA Far East Efforts to market Harpagophytum Effects of trade in Harpagophytum 219

7 Area to be harvested in Namibia to meet export quantities Area to be harvested in South Africa to meet export quantities Domestic and regional trade International trade Organic certification Intellectual property rights - patents Conservation measures - CITES Conclusions and summary on the trade in Harpagophytum Legislation in Harpagophytum Methods Namibia South Africa Botswana Conclusions and summary on the legislation in Harpagophvtum Final discussion and conclusions Spatial occurrence of Harpagophytum Impact of non-sustainable harvesting on populations of Harpagophytum Non-sutstainable harvesting in high resource areas Non-sutstainable harvesting in low resource areas Impact of the harvesting season Incentives to get involved in the trade of Harpagophytum Spatial extent of harvesting Impact of the market on wild harvesting and cultivation Decreasing market prices Increasing market prices Different incentives to sustainability Namibia Population and utilisation status of Harpagophvtum Regeneration potential Conclusions on the resource status in Namibia Recommendations for Namibia South Africa Population and utilisation status of Harpagophytum Regeneration potential Conclusions on the resource status in Namibia Recommendations for Namibia Conclusions or is Harpagophytum threatened? Executive Summary Zusammenfassung References Attachments 267