Ecological Models Reveal a Weakened Population Structure, and Distribution Drivers of Osyris lanceolata (Santalaceae) in the Karamoja Sub-Region, Uganda — Oak Academic Publishing
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Ecological Models Reveal a Weakened Population Structure, and Distribution Drivers of Osyris lanceolata (Santalaceae) in the Karamoja Sub-Region, Uganda
Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
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Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
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Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
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Institute of Integrative Nature Conservation Research, Department of Ecosystem Management, Climate and Biodiversity, BOKU University, Vienna, Austria
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Institute of Integrative Nature Conservation Research, Department of Ecosystem Management, Climate and Biodiversity, BOKU University, Vienna, Austria
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National Fisheries Resources Research Institute, National Agricultural Research Organisation (NARO), Jinja, Uganda
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College of Environmental and Agricultural Sciences, Makerere University, Kampala, Uganda
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Institute of Development Policy (IOB), University of Antwerp, Antwerp, Belgium
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Kenya Forestry Research Institute, Nairobi, Kenya
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Department of Agricultural and Environmental Sciences, Bugema University, Kampala, Uganda
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BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
1 Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
2 Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
3 Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
4 Institute of Integrative Nature Conservation Research, Department of Ecosystem Management, Climate and Biodiversity, BOKU University, Vienna, Austria
5 Institute of Integrative Nature Conservation Research, Department of Ecosystem Management, Climate and Biodiversity, BOKU University, Vienna, Austria
6 National Fisheries Resources Research Institute, National Agricultural Research Organisation (NARO), Jinja, Uganda
7 College of Environmental and Agricultural Sciences, Makerere University, Kampala, Uganda
8 Institute of Development Policy (IOB), University of Antwerp, Antwerp, Belgium
9 Kenya Forestry Research Institute, Nairobi, Kenya
10 Department of Agricultural and Environmental Sciences, Bugema University, Kampala, Uganda
11 BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
Osyris lanceolata is heavily and illegally exploited in East Africa for its essential oils, yet little is known about its population status and ecological requirements. This study examined its population structure and environmental factors influencing its distribution in the semi-arid Karamoja sub-region, Uganda. We surveyed 388 plots (5 m radius) at different altitudes, recording life stages, stem diameters, and regeneration patterns, and analyzed soil samples. Multivariate analyses, including Canonical Correspondence Analysis (CCA), Detrended Correspondence Analysis (DCA), Non-metric Multidimensional Scaling (NMDS), and Multiple Regression Modeling (MRM), identified key environmental factors affecting its distribution. Findings show that O. lanceolata populations in Moroto, Nakapiripirit, and Amudat districts are severely degraded due to overexploitation. The species is primarily regenerating through coppicing rather than seedlings, with an exploitation intensity of 56.6%. Population densities are low, distribution is irregular, and sustainable harvesting is not viable. Soil properties, particularly Ca 2 + , N, P, K + , Na + , and organic matter, significantly influence its abundance. Conservation efforts should focus on identifying suitable provenances for genetic preservation and plantation establishment. Areas with at least 9 trees per hectare in Moroto, Nakapiripirit, and Amudat could serve as potential sites for ex-situ plantations. Further research should explore how biotic interactions, genetic diversity, and morphology affect oil yield and quality to support restoration, breeding, and domestication initiatives.
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