BRANTA — Ilya Maclean
An ecological and socio-economic analysis of biodiversity conservation of East African wetlands
Institution: University of East Anglia, Norwich, UK
Supervisors: M Hassall, R Boar
Details: PhD 2004 (Completed)
Current Address: British Trust for Ornithology, The Nunnery, Thetford, IP24 2PU (Oct 2005) Email
Subject Keywords: Cyperus papyrus, wetland drainage, Uganda, applied ecology, conservation
Species Keywords: White-winged Warbler Bradypterus carpalis, Papyrus Yellow Warbler Chloropeta gracilirostris, Carruthers's Cisticola Cistocola carruthersi, Greater swamp warbler Acrocephalus rufescens, Papyrus GonolekLaniarius mufumbiri, Papyrus Canary Serinus koliensis
Abstract:
East African papyrus Cyperus papyrus swamps have undergone wide-scale drainage and are used intensively by resources harvesters. They also support a unique biota, notably six inadequately protected bird species. In this thesis, the results of a study examining the socio-economic benefits of and avian responses to wetland drainage and resource use are presented.
The species richness of bird communities in heavily disturbed papyrus stands was higher than in nearby stands that were not disturbed, but contained fewer species and individuals of specialised species. However, even the six most specialised species were tolerant of low-intensity disturbance. Using a time-series of Landsat ETM images covering southern Uganda and adjoining countries wetlands were mapped and regional variations in drainage quantified. Using land coverage and occurrence data, the abundance and decline of bird species in c. 30,000 East African wetlands was predicted. The species studied appear to have declined substantially more than predicted by ecological theory because population densities were higher in regions in which most drainage has occurred. Although average drainage was only c. 9% over 15 years, drainage in regions in which bird density was highest exceeded 75% over this period.
The socio-economic value of crops grown in reclaimed swamps and goods derived from swamps were determined by interviewing rural householders. Results indicated that although drainage always served to reduce the net present value (NPV) of goods derived from swamps, NPV was maximised when 25-30% of the swamp was used for harvesting. Drainage and harvesting exceeded these levels, in part because property rights structures have shifted from common ownership to open-access and in part because income equality is low and poorer people are more inclined to use and drain swamps. The results of this study suggested that there were similarities between swamp use that maximises socio-economic benefits and management that favours specialist bird species. This would imply that conservation action designed to protect papyrus avian communities could also be of benefit to rural inhabitants using swamp resources. However mutual benefits to birds and people are dependent upon reducing poverty.
Published Papers
Maclean, I.M.D., Hassall, M., Boar, R.R. & Nasirwa, O. 2003. Effects of habitat degradation on avian guilds in East African papyrus Cyperus papyrus L. swamps. Bird Conservation International 13: 283-297.
Maclean, I.M.D., Musina, J., Nalianya, N., Mahood, S., Martin, R. & Byarunhanga, A. 2003. Systematics, distribution and vocalisation of Papyrus Yellow Warbler Chloropeta gracilirostris. Bulletin of the African Bird Club10: 94-100.
Maclean, I.M.D., Tinch, R., Hassall, M. & Boar, R.R. 2003. Social and economic use of wetland resources: a case study from Lake Bunyonyi, Uganda. Centre for Social and Economic Research into the Global Environment, University of East Anglia, Norwich.
Maclean, I.M.D., Tinch, R., Hassall, M. & Boar, R.R. 2003. Towards optimal use of tropical wetlands: an economic evaluation of goods derived from papyrus swamps in southwest Uganda. Centre for Social and Economic Research into the Global Environment, University of East Anglia, Norwich.