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Nantongo J.S.,National Forestry Resources Research Institute | Eilu G.,Makerere University | Geburek T.,Research Center for Forests | Schueler S.,Research Center for Forests | Konrad H.,Research Center for Forests
PLoS ONE | Year: 2016

In flowering plants, self-incompatibility is an effective genetic mechanismthat prevents self-fertilization. Most Prunus tree species exhibit a homomorphic gametophytic self-incompatibility (GSI) system, in which the pollen phenotype is encoded by its own haploid genome. To date, no identification of S-alleles had been done in Prunus africana, the only member of the genus in Africa. To identify S-RNase alleles and hence determine S-genotypes in African cherry (Prunus africana) fromMabira Forest Reserve, Uganda, primers flanking the first and second intron were designed and these amplified two bands in most individuals. PCR bands on agarose indicated 26 and 8 different S-alleles for second and first intron respectively. Partial or full sequences were obtained for all these fragments. Comparison with published S-RNase data indicated that the amplified products were S-RNase alleles with very high interspecies homology despite the high intraspecific variation. Against expectations for a locus under balancing selection, frequency and spatial distribution of the alleles in a study plot was not random. Implications of the results to breeding efforts in the species are discussed, and mating experiments are strongly suggested to finally prove the functionality of SI in P. africana. © 2016 Nantongo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Kiyingi I.,National Forestry Resources Research Institute | Bukenya M.,Makerere University
Southern Forests | Year: 2010

The different interests in forest resources by various stakeholders may result in differences in perceived value of forest conservation. In order to test this hypothesis, we compared the valuation by international ecotourists and local respondents of the perceived benefits of the Mabira Central Forest Reserve. The factors that influenced respondents' valuation of forest conservation were also investigated. Describing a hypothetical scenario to elicit respondents' willingness-to-pay (WTP) for forest conservation was the central part of the questionnaire. The WTP;income ratio was used to estimate respondents' perceived value of forest conservation. A chi-square (χ2) test indicated significant association between respondent category (local and tourist) and categories of perceived benefits (p-value = 0.001). The locals were more interested in direct-use values while the tourists showed greater interest in the indirect-use values. A Student's t-test showed that the WTP:income ratios of the locals were much higher than for the ecotourists (p-value < 0.001). This implies that the local communities had a higher valuation of forest conservation than the ecotourists. Regression analysis revealed that all other factors being constant, the WTP of respondents who perceived direct- and indirect-use value as the most important forest benefit was significantly higher (p < 0.05) than those who perceived no value by $5.8693 and $0.02628, respectively. The respondents who rated the contribution of the ecotourism project to community development as moderate had a significantly higher WTP compared to those who rated it as low by $6.6908. Overall, these results indicate that the benefits people derive from the forest either through direct or indirect uses influence valuation of forest conservation. Results also indicate that although ecotourismrelated benefits improved attitudes towards forest conservation, ecotourism alone may not be an adequate conservation tool because of the limited support it can provide to the local community. © NISC (Pty) Ltd.

Kiyingi I.,National Forestry Resources Research Institute | Kiyingi I.,University for Development Studies | Edriss A.-K.,University for Development Studies | Phiri A.M.R.,University for Development Studies | And 3 more authors.
Southern Forests | Year: 2016

This study assessed the amount of carbon stored and the economic viability of the small-scale Clean Development Mechanism (CDM) carbon offsets in Pinus caribaea and Eucalyptus grandis plantations under varying rotations. Volume equations were used to estimate carbon stocks and merchantable wood volume in the plantations, while net present value (NPV) and annual equivalent value (AEV) were used as measures of profitability at the optimum economic rotation age as well as at the CDM-defined crediting period of 20 years. The findings show that over a 20-year rotation, E. grandis and P. caribaea plantations sequestered 638 and 418 t CO2-e ha−1, respectively. The NPVs of E. grandis and P. caribaea with carbon credits over the CDM carbon-crediting period of 20 years were US$2 540 ha−1 and US$1 814 ha−1, respectively. This is higher than the NPVs without carbon credits of US$1 543 ha−1 and US$1 390 ha−1 for E. grandis and P. caribaea, respectively. The AEV of E. grandis harvested at its optimal economic rotation of 10 years was US$316 ha−1. This is slightly higher than the AEV of US$298 ha−1, utilising the CDM carbon-crediting period of 20 years. In contrast, the AEV of P. caribaea under the 20-year CDM carbon-crediting period was higher than harvesting at the optimal economic rotation of 16 years without carbon credits. When the average CDM contract establishment costs exceed US$500 ha−1 and US$1 000 ha−1 for P. caribaea and E. grandis woodlots, respectively, it is not economically viable for one to participate in the CDM forest carbon offsets programme. In conclusion, the study results indicate that whereas E. grandis has a higher biological potential to sequester carbon than P. caribaea, it is currently not economically viable for participation in the CDM forest carbon offset scheme. In contrast, it is economically viable for P. caribaea plantations to participate in the CDM, if the CDM contract establishment costs are low. © 2016 NISC (Pty) Ltd

Gwali S.,Makerere University | Gwali S.,National Forestry Resources Research Institute | Okullo J.B.L.,Makerere University | Eilu G.,Makerere University | And 3 more authors.
Ethnobotany Research and Applications | Year: 2011

Folk knowledge has been the basis for selection and improvement of many food crops such as potatoes, sorghum, yams, cassava and rice. In Uganda, there is strong potential to utilize folk knowledge to select and domesticate the shea butter tree (Vitellaria paradoxa C.F. Gaertn. subsp. nilotica (Kotschy) A.N. Henry & Chithra & N.C. Nair), an important economic tree species. Farmers report high variation in fruit yield, tree form and pulp taste. In this study, we documented shea tree folk classification by interviewing 300 respondents, 15 focus groups and 41 key informants across three farming systems of Uganda. Data were analyzed using Kruskall-Wallis and Spearman's tests, Chi-square, Multivariate, Factor and Discriminant Function Analyses. Folk classification and nomenclature of shea tree ethno-varieties is based on fruit/nut organoleptic (color and taste) and morphological attributes. Interestingly, despite the socio-cultural importance of shea oil, it does not feature as a factor in the folk classification and nomenclature of shea tree ethno-varieties. There was no significant difference in classification knowledge across the three farming systems (Kruskal - Wallis χ2 = 28, df = 28, p > 0.05; Spearman's R > 0.8, p < 0.0001) although there was significant influence from ethnicity of the respondents (Pillai's trace = 0.817, p < 0.001). While this study provides a record of shea tree ethno-varieties and associated classification criteria, there is need to validate these 'ethno-varieties' using detailed morphological, biochemical and molecular analyses.

Gwali S.,National Forestry Resources Research Institute | Okullo P.,National Forestry Resources Research Institute | Hafashimana D.,National Forestry Resources Research Institute | Byabashaija D.M.,National Forestry Resources Research Institute
Tropical Conservation Science | Year: 2010

The successful management of natural resources requires access to adequate information on social, economic, ecological, and cultural changes in order to mitigate their impacts through conservation interventions. In most cases, such information is provided in the form of simple diversity indices, which may not predict the complex nature of species functioning in ecosystems. In this study, we used rank abundance, analysis of similarities (ANOSIM), similarity percentages (SIMPER), and taxonomic-diversity and distinctness indices to show the status of tree and shrub species in Kasagala forest reserve in central Uganda. Four 100 × 100 m plots were established in four vegetation strata of the strict nature reserve of the forest, and diameter at breast height (DBH) of trees and shrubs ≥ 5 cm measured. There was no significant difference in species abundance in the four vegetation strata (Kruskal Wallis H = 2.614, p = 0.453; ANOSIM: R = -0.334, p = 0.995). The taxonomic diversity and distinctness of the four vegetation types ranged between 2.414 and 2.786 while the taxonomic distinctness values ranged between 2.897 and 2.978. The taxonomic diversity of the forest is generally even, suggesting a homogeneous community. We suggest that the managers of the forest constitute a continuous monitoring program aimed at controlling the impact of anthropogenic factors, one of the main influences for such low taxonomic distinctness values observed for this forest. © Samson Gwali, Paul Okullo, David Hafashimana and Denis Mujuni Byabashaija.

Gwali S.,National Forestry Resources Research Institute | Okullo P.,National Forestry Resources Research Institute | Hafashimana D.,National Forestry Resources Research Institute | Byabashaija D.M.,National Forestry Resources Research Institute
African Journal of Ecology | Year: 2010

The diversity and composition of trees and shrubs of ≥5 cm diameter at breast height (DBH) were investigated in Kasagala woodland in central Uganda using 1 ha permanent sample plots. A total of 2745 trees and shrubs with a mean stem density of 686 ha-1 were recorded. These included 69 tree species belonging to 28 families and 47 genera. There was a larger number of small stems compared with that of larger stems. There was significant variation in stem size class distribution between the plots (F = 3.14, P = 0.027). The variation in stem densities (counts) across different size classes was significant (F = 8.31, P < 0.001). Species diversity was higher in the low lands compared with that in the elevated sites in the woodland. The species encountered were unevenly distributed across the plots. Species abundance was not significantly different across the sample plots (F = 2.63, P = 0.053). We suggest that the structure of the forest is typical of any regenerating forest, but other human influences may have played a part in the dominance of size classes <10 cm DBH. The causes of the present status and composition of the woodland require further investigation. © 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd.

Kiyingi I.,National Forestry Resources Research Institute | Kidiya J.M.,National Forestry Resources Research Institute | Gwali S.,National Forestry Resources Research Institute | Okullo P.,National Forestry Resources Research Institute | Byabashaija D.M.,National Forestry Resources Research Institute
Southern Forests | Year: 2010

The study investigated the tree species composition, vegetation structure and harvesting pattern to guide management of the Maruzi Hills Forest Reserve. Stratified random sampling was used to site six (100 m × 100 m) permanent sample plots in the woodland, bushland and grassland vegetation types identified in the reserve. Rényi diversity profiles indicated that bushland vegetation had a lower Shannon diversity index (H = 2.054) than grassland (H = 2.38) and woodland vegetation (H = 2.319). Grassland and woodland vegetation also had lower proportions of the dominant species (α∞ = 1.15 and 1.66, respectively) than bushland vegetation (α∞ = 3.25). However, the mean stem density of the woodland, bushland and grassland vegetation was 214 stems ha-1, 191 stems ha-1 and 114 stems ha-1, respectively. Bray-Curtis and Jaccard ecological distance matrices showed that, although the three vegetation types shared some common species, the ecological distances were relatively high suggesting significant species composition variation between the vegetation types, particularly between the bushland and the other vegetation types. The species with the highest proportional abundance in the survey were Combretum molle (23%), Acacia hockii (17.7%), Combretum collinum (16.1%), Grewia mollis (6.5%) and Lannea barteri (6.5%). Diameter size-class distribution of woody perennials and tree stumps indicated higher frequencies of the smaller-diameter size classes. The stump records were indicative of charcoal burning and firewood collection as major causes of tree/shrub harvesting. The Maruzi Hills woodland conservation strategy should consider the differences in species composition between vegetation types if the highest number of species is to be conserved. © NISC (Pty) Ltd.

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