Browsing by Author "Msalilwa, Upendo"

Now showing 1 - 5 of 5

Assessment of the status of African Baobab populations and fatty acids composition of its crude oil in semi arid areas of Tanzania
(NM-AIST, 2021-07) Msalilwa, Upendo
Baobab (Adansonia digitata L.) is a deciduous non-timber tree species that is facing severe threats from both anthropogenic and climatic pressures across its range states. Additionally, baobab seed oil has been used for many years by local populations as medicine to treat different diseases, beauty, and food purposes. However, consumption of baobab seed oil has been reported to cause health effects emanating from the presence of carcinogenic ingredients known as Cyclopropenoid Fatty Acids (CFPAs). Ecological survey and laboratory analysis were carried out to asses the status of Baobab populations and characterize their fatty acid of seeds clued oil respectively. In ecological survey, stratified random sampling design composed of the three land-use types: strictly protected areas, non-strictly protected areas, and unprotected areas were used to select the grids for the study. Baobabs were sampled in belt transect of 1 km long and a 50 m wide, which were carried out in 337 grids located in three different land-uses types. In the laboratory analysis, the physico-chemical properties were determined according to Official Methods of Analysis of the Association of Official Analytical Chemists. The quantification of fatty acid before and after heating was done by the analysis of derivative fatty acid methyl-esters by using Gas-Liquid Chromatography. Baobab density was found to be highest in strictly protected areas (2.45 ± 1.29) and the lowest in unprotected areas (1.52 ± 1.00). The density of adult, sub-adult and juvenile populations were 1.53 ± 0.105, 0.82 ± 0.149 and 0.33 ± 0.253 plants/ha respectively. Furthermore, the results show bell shaped and inverse J-shaped distributions in the unprotected areas and strictly protected areas, respectively. The number of baobabs damaged was higher than undamaged in all land-use types. There were no significant differences in terms of physico-chemical properties in three different regions. It was found that the baobab crude oil contains mainly twelve essential fatty acids and two different CFPAs. The most abundant fatty acids were Palmitic acid, Oleic acid and Linoleic acid in all the three regions. The major breakdown of CPFAs started at 200 °C that would be the best temperature in the refining process of the baobab oil. The findings from this study are important in understanding the status of baobab populations and CPFAs of their crude oil in different land uses and serve to inform decision akers towards sustainable management of this species. Furthermore, the information from this study is vital in understanding the role of biophysical conditions and land uses in shaping the population persistence of the species in its range areas in Tanzania.
Demography of baobab (Adansonia digitata L.) population in different land uses in the semi-arid areas of Tanzania
(Elsevier, 2020-12) Msalilwa, Upendo; Ndakidem, Patrick; Makule, Edna; Munishi, Linus
Baobab is a deciduous non-timber tree species that are facing severe threats from both anthropogenic and climatic pressures across its range states. This study assessed natural rates of recruitment and associated threats of baobabs within and across different land-use types in semi-arid areas of Tanzania. The study was based on a stratified random sampling design composed of the following land-use types: strictly protected areas, non-strictly protected areas, and unprotected areas. Rates of recruitment were measured from a total of 337 grids (representing 40% of semi-arid land) in three different land-use types in a plot measuring 1 km long and 50 m wide. Results show that juvenile, sub-adult and adult baobab populations varied significantly (p < 0.001) within and across land-use types with only 4.7% of surveyed plots having a few juveniles (about four stems per plot) across the study area. The density of adult, sub-adult and juvenile populations were 1.53 ± 0.105, 0.82 ± 0.149 and 0.33 ± 0.253 plants/ha respectively with strictly protected areas (national parks) supporting the most abundant (53%) of the adult trees. Furthermore, the results show inverse J-shaped and bell-shaped distribution in the strictly protected areas and unprotected areas, respectively. The densities of mature baobabs were found to be higher than juvenile baobabs in all three land-use types. The number of baobabs damaged was higher than undamaged in all land-use types. Our results suggest that anthropogenic threats are higher than biophysical factors in driving the species to mortality and population extirpation. Likely, baobab size and distribution across land-use types are mostly influenced by herbivory and fire that likely limit the establishment in most of these areas. Strategies promoting the recruitment and sustainable harvesting practices of baobab would perhaps be the best options to support the population persistence in different land uses in semi-arid areas. The study recommends more studies to understand the factors affecting germination and recruitment rates in order to predict future distributions in semi-arid environments. Also in defining and planning for different land-use system, baobab species should be taken into consideration and in particular in agroforestry farms can easily qualify as a tree crop. Promotion of active recruitment through planting especially in communal lands and protection from herbivory is required if we are to overcome the recruitment bottlenecks as influenced by increasing impacts of land use and climate change and overexploitation. The intentional growing of trees and shrubs in combination with crops cultivation and forage production is also recommended to smallholder farmers.
Emerging issues and challenges associated with conservation of the African baobab (Adansonia digitata L.) in the semi-arid areas of Tanzania
(International Network for Natural Sciences, 2019-11) Msalilwa, Upendo; Munishi, Linus; Makule, Edna; Ndakidemi, Patrick
The aim of this review is to discuss the emerging issues and challenges in baobab conservation based on the climate change, emerging challenges related to herbivory and human use such as emerging of new markets for baobab products and land use changes.Specifically, the review summarizes scientific questions and challenges for the conservation of one of the most important indigenous fruit tree species, Adansonia digitata in Sub-Saharan Africa. It highlights on new information on the status of A. digitata in Tanzania with a strong focus on ethno-botanical issues, traditional and modern uses as well as challenges for the management and conservation of the tree species.We have done that by using facts from different parts of the geographical ranges of Africa and other parts of the world. The review is based on the belief that understanding the factors underpinning the use and management of A. digitata is an essential step towards development of credible strategies and plans that would advance and lead to sustainable management of baobabs.
Physicochemical Properties, Fatty Acid Composition, and the Effect of Heating on the Reduction of Cyclopropenoid Fatty Acids on Baobab (Adansonia digitata L.) Crude Seed Oil
(Hindawi, 2020-12-14) Msalilwa, Upendo; Makule, Edna; Munishi, Linus; Ndakidemi, Patrick
The baobab seed oil has been consumed by humans due to its medicinal and nutrient values for many years. However, the consumption of baobab seed oil has been perceived by different communities as a health risk caused by cyclopropenoid fatty acids (CPFAs), which are carcinogenic ingredients present in the oil. This study investigated the physicochemical properties and fatty acid profile of baobab crude seed oil collected from semiarid areas in Tanzania and determined the effects of heating on the reduction of CPFAs. The baobab seed crude oil was extracted by Soxhlet using n-hexane, and the fatty acid composition of the baobab seed crude oil was determined by gas-liquid chromatography (GLC). Since CPFAs are resistant to lower temperatures, the effect of heating on the CPFA content of baobab crude seed oil was studied at 150° C, 200° C, and 250° C. The A. digitata crude seed oil was found to contain mainly twelve essential fatty acids and two different CPFAs. The most abundant fatty acids were palmitic acid, oleic acid, and linoleic acid in all the baobab population hotspots occurring in Tanzania. There was no significant difference in most physicochemical properties and fatty acid composition across the different semiarid areas in Tanzania. The major breakdown of CPFAs occurs at 200° C, and that would be the optimal temperature recommended for the refining process of the baobab crude oil. The study recommended refining of the baobab oil at higher temperatures ranging from 200 - 250° C as the best way of reducing CPFAs.
Pinpointing baobab (Adansonia digitata [Linn. 1759]) population hotspots in the semi‐arid areas of Tanzania
(John Wiley & Sons, 2019-11-15) Msalilwa, Upendo; Munishi, Linus; Makule, Edna; Ndakidemi, Patrick
The impact of unsustainable land‐use conversions, changes in climate and anthropogenic activities on abundance and distribution of baobab populations was assessed in semi‐arid regions of Tanzania. Baobabs were sampled in plots of 1 km long and a 50 m wide, which were carried out in 337 grids located in different land‐use types. Transects for each land‐use type were located using a stratified random sampling technique to compare baobab population variations and occurrences in semi‐arid areas of Tanzania. Baobab density was found to be highest in strictly protected areas and the lowest density in unprotected areas, suggesting that anthropogenic activities coupled with local management practices within land‐uses may be influencing its viability in semi‐arid areas. In species like this, with less and slow recruitment rate, it takes a long time to bring the population to recovery when substantial disturbance and overutilisation have reduced the populations to certain levels. Thus, increased human and climate change pressures on land are likely to drive the species to extinction in these fragmented populations.