Browsing by Author "Shirima, D"

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Does the abundance of dominant trees affect diversity of a widespread tropical woodland ecosystem in Tanzania
(Cambridge University Press, 2015-05-04) Munishi, P; Shirima, D; Totland, O; Moe, S
Dominant woody species can determine the structure and composition of a plant community by affecting environmental conditions experienced by other species. We explored how dominant tree species affect the tree species richness, diversity, evenness and vertical structural heterogeneity of non-dominant species in wet and dry miombo woodlands of Tanzania. We sampled 146 plots from eight districts with miombo woodlands, covering a wide range of topographic and climatic conditions. We recorded 217 woody plant species belonging to 48 families and 122 genera. Regression analysis showed significant negative linear associations between tree species richness, relative species profile index of the non-dominant and the relative abundance of the dominant tree species (Brachystegia spiciformis and Brachystegia microphylla in wet, and Brachystegia spiciformis and Julbernardia globiflora in dry miombo woodlands). Shannon diversity and evenness had strong non-linear negative relationships with relative abundance of dominant tree species. A large number of small individual stems from dominant and non-dominant tree species suggesting good regeneration conditions, and intensive competition affecting survival. We suggest that dominant miombo tree species are suppressing the non-dominant miombo tree species, especially in areas with high recruitments, perhaps because of their important adaptive features (extensive root systems and ectomycorrhizal associations), which enhance their ability to access limited nutrients.
Soil organic carbon and emission factors for different land cover classes in Tanzania
(Tanzania Journal of Forestry and Nature Conservation, 2022) Mauya, E.W.; Massawe, B.H; Madundo, S; Shirima, D; Zahabu, E.
Quantification of carbon stock and development of country-specific emission factors in relation to the Agriculture, Forestry, and Other Land Use (AFOLU) sector has the potential to improve national greenhouse gas inventory systems. This study was therefore, conducted to quantify soil organic carbon (SOC) and develop emission factors using the national forest inventory data of Tanzania. The results, showed that, the mean SOC for the different land cover subclasses ranged from 31.23 Mg C /ha to 99.8 Mg C /ha. The lowest value being recorded in the bushland thicket and highest value in the forest humid mountains. Spatial interpolation map indicated that, large areas in the central part had low values of SOC, ranging from 0-53Mg C/ha. The SOC for the primary land cover classes were 37.32 Mg C/ha, 43.44 Mg C/ha, 39.68 Mg C/ha for forest, non-non forest and wetlands respectively. Their correspondingly annual emission factors were, 3.56 Mg CO2/ha/yr, 4.14 Mg CO2/ha/yr, and 3.78 Mg CO2/ha/yr, respectively. The values presented in this paper correspond to IPCC tier 2 and can be used for estimation of carbon emission at the national scale for the respective major primary land cover classes.