Southwest Tanzania Research Articles

Assessment of Physicochemical Profile and Heavy Metal Constituents in the Groundwaters of Rural Areas in Southwest Tanzania

Assessment of Physicochemical Profile and Heavy Metal Constituents in the Groundwaters of Rural Areas in Southwest Tanzania

Mythologising Nyerere and Recreation of a National Hero in Banyakyusa Narratives

This article examines the myths about Mwalimu Julius Nyerere, the first president of Tanzania, in Banyakyusa narratives. It uses narrative and new historicism theories to capture the recreation of Nyerere as a national hero and understand the interplay between his representation in myths and his depiction in historical and biographical documents. The myths were collected from Busokelo, Kyela, and Rungwe districts in southwest Tanzania. The Banyakyusa believe Nyerere was endowed with massive mystical powers, which helped him win against colonialists, defeat Idi Amin, and build multiparty democracy. Politicians, historians, and the media play a significant role in the recreation or whitewashing of the Nyerere myths.

Structure, regeneration and carbon stocks of woody plants in the Litwang’ata village land forest reserve, Southwest Tanzania

Abstract The plant biodiversity status of many village land forest reserves is little known to support meaningful implementation of sustainable forest management objectives in Tanzania. This study was conducted to assess the status of Litwang’ata village land forest reserve in Ludewa district, Southwest Tanzania through 20 square sample plots of 10 × 10 m. A total of 20 woody plant species belonging to 12 families and 19 genera with DBH ≥ 5 cm were identified in the study forest. The most important species with their importance value index were Brachystegia spiciformis (78.02), Brachystegia boehmii (22.05), Faurea saligna (15.18), Uapaca kirkiana (14), Acacia amythethophylla (13.07), Pseudolachnostylis maprouneifolia (12.76) and Gardenia ternifolia (10.36). The forest had a Shannon diversity index (H´) of 2.27, indicating medium diversity. Stand structure comprised 1,330 ± 523 stems ha–1, basal area of 18.97 ± 6.81 m2 ha–1 and stand volume of 142.36 ± 52.17 m3 ha–1. The mean above- and belowground carbon stocks were 46.97 ± 17.23 Mg ha–1 and 23.90 ± 8.58 Mg ha–1 respectively. The higher tree densities, basal area, stand volume and carbon stocks recorded in this study compared to other Miombo woodlands indicate that Litwang’ata forest is still in good condition, and managment efforts should be strengthened to bolster biodiversity conservation for present and future generations.

Assessing exclusive breastfeeding knowledge and practice among women in Mbeya, Southwest Tanzania: A cross-sectional study

IntroductionInadequate infant feeding practices pose a significant social and economic development barrier and a serious health threat for children under five worldwide. Although over 90 % of African children aged 0–5 years are breastfed, in many countries, including Tanzania, less than half of infants aged 0–6 months receive exclusive breastfeeding (EBF) as recommended by the World Health Organization. ObjectiveThe primary objective of this study is to assess the knowledge and practices regarding EBF among women in Mbeya. MethodsA cross-sectional study was conducted among women with children under six months attending the Reproductive and Child Health (RCH) clinic at Mbeya Zonal Referral Hospital (MZRH) in August 2022. Data was collected by face-to-face interviews using a structured questionnaire. Recorded information included age, level of education, marital status, occupation, number of children and other factors associated with EBF. ResultsOf 371 respondents, 77.4 % had prior knowledge of EBF. However, only 52.8 % reported practicing it, while 47.2 % did not. Knowledge of EBF was significantly associated with its practice (p < 0.001). The number of children was also significantly associated with EBF practice (p = 0.002). Understanding the importance of breastfeeding was significantly associated with EBF practice (p < 0.001), as did demographic factors (p < 0.001). However, respondent age was not significantly associated with EBF practice (p = 0.643). ConclusionThe study revealed a slightly lower EBF prevalence than the national estimate, indicating a public health concern in Mbeya. Findings highlight the need for continued education and support to promote EBF among women.

Climate Change, Remodelling of Oral Tales and the Changing Ways of Life: The Case of the Sangu of Tanzania

African oral literature is not static; it changes in accordance with and in relation to the changes occurring in the society it reflects. As a rich source of varying degrees of information, African oral literature depicts the changing human conditions and behaviour like climate and related environmental conditions, crime, political instability, disease amongst others; and provides requisite solutions to such piercing and compelling global challenges. This paper presents a textual analysis of four (4) Sangu oral tales to show how the Sangu of south-west Tanzania have been remodelling their tales in relation to the changing human life conditions. It scrutinises “iJungwa Sikhandi Vaanu” (lit. trans. ‘elephants were once human beings’), “Umutwa nu Mwehe Waakwe” (‘the chief and his wife’), “Umuhinja ni Nyula” (‘a girl and the frogs’), and “Kwashi iNwiga sina Singo Nali”(‘why giraffes have long necks’), which were part of the 20 tales collected during in-depth interviews held with Sangu storytellers. The selection of these four tales was based in their suiting the climate change theme and remodelling. The study found that oral stories display unique knowledge of a particular people pertaining to climate change and adaptation. Moreover, it emerged that sustainable solutions to the current environmental crisis are embedded in people’s environment-related oral narratives.

Seroprevalence and risk factors for Taenia spp infection in pigs in Kongwa and Songwe districts, Tanzania: A cross-sectional study

Taenia solium porcine cysticercosis (PCC) is widespread in many low- and middle-income countries (LMICs) where free-range pig rearing is common and hygienic standards are subpar. A cross-sectional survey was conducted in 42 villages between June and September 2019 (14 in Songwe district, southwest Tanzania, and 28 in Kongwa district, central Tanzania). Using a commercial Ag-ELISA kit (apDia, Belgium), circulating antigens of Taenia spp in pig serum were identified and used to calculate the PCC seroprevalence. The study recruited 692 randomly selected households, sampling one pig per household. The relationship between each risk factor and the seroprevalence of PCC at the household and village levels was analysed using mixed logistic regression models. The findings showed that approximately 28% of the pigs were reared in free-range settings, the proportion of households with latrines across the districts was 92%. Twenty-seven percent of households with latrines had water and soap available for hand washing. Sixty-seven (9.7%) tested positive for PCC based on Ag-ELISA. The overall seroprevalence in Kongwa and Songwe districts was 7.3% and 14.0% respectively. In addition, the overall village Ag-ELISA positivity was 9.3%, with an interquartile range (IQR) of 4.6% – 14.1%. Increasing the age of the pig (OR = 3.13 95% CI = 1.48 – 6.60; p = 0.003), pig originating from outside the household (OR = 0.5 95% CI = 0.25 – 0.99; p = 0.05), and pigs kept in a household that practised deworming (OR = 2.23 95% CI = 1.08 – 4.61; p = 0.03) were important risk factors associated with PCC positivity. Therefore, the high seroprevalence of PCC, up to 14%, calls for rapid and effective control actions such as vaccination and treatment of pigs against PCC, and public health education emphasises on indoor pig rearing, hygienic practices and regular use of latrines. Our findings also point to a potential danger of Taenia. spp infection indicating the possibility of people carrying the adult parasite Taenia solium not only in the rural communities of Kongwa and Songwe districts but also in the urban areas of Tanzania, where pigs from these areas are transported for consumption. To develop effective management measures, further research on taeniasis and cysticercosis in the human population is required.

Mineral prospectivity modelling to delineate potential areas for gold deposits: a case study of Lupa Goldfield, South West Tanzania

ABSTRACT This study used the weight of evidence model to delineate prospective areas for gold deposits in the Lupa Goldfield. The method establishes a spatial relationship between known mineral deposits and evidential maps to create a mineral prospectivity map. Four evidential maps derived from geochemical, geological, geophysical, and topographical Digital Elevation Model (DEM) datasets were analysed and integrated to create a mineral prospectivity map. Results have revealed five classes ranked from the highest, high, medium, low, and lowest favourability patterns with probability values of 0.051, 0.0426, 0.0225, 0.0172, and 0.0091, respectively. The highest favourable areas have the best gold potentials based on the presence of predictor patterns from all four evidential maps. The posterior probability map revealed good prediction, existing gold deposits, such as Saza Mine and Shanta Gold Mine, were mapped. Results have shown that the weight of evidence model was successful and can be applied in mineral exploration targeting.

Assessing knowledge, attitude and practice towards prostate cancer screening among males in Southwest Tanzania: A cross-sectional study

BackgroundProstate cancer is common among men, and awareness can reduce associated deaths. Low knowledge of prostate cancer screening and wrong perceptions about prostate cancer leads to poor screening practices. Our study assessed knowledge, attitude and practice towards prostate cancer screening among male adults at Mbeya Zonal Referral Hospital. MethodsThis hospital-based cross-sectional study used a random sampling technique to select men attending the hospital. Data was collected using a questionnaire on socio-demographic characteristics, personal and familiar medical history of prostate cancer, knowledge about prostate cancer and its screening. Data analysis was done using SPSS version 23. ResultsOne hundred and thirty-two (132) men participated in the study. Participants ranged from 18 to 75 years, with a mean age of 41.57. This study found that while 72% of respondents had heard of prostate cancer, only 43.9% had knowledge of prostate cancer screening. Age was associated with prostate cancer screening knowledge (COR = 1.03, 95% CI: 1.01–1.54, p < 0.001). Only 29.5% of respondents had a positive attitude toward prostate cancer screening. A small percentage (16.7%) had been tested for prostate cancer, but the majority (89.4%) were willing to be screened in the future. ConclusionThe study found that while most men in the study area had a basic understanding of prostate cancer, only a small percentage had a favourable knowledge of prostate cancer screening, with a low positive perception of screening. The study highlights the need to increase awareness of prostate cancer screening in Tanzania.

Low-cost Chinese goods in Tanzania: the rise of transnational trade routes’ peripheral branches

This article illustrates how rural margins and urban-rural relations in southwest Tanzania join up with transnational trade routes for Chinese goods. It examines the trade of low-cost imported goods from China (plastic sandals, cheap jewellery, various fashion accessories, cheap clothing, etc.) that are widely spread in Tanzania, up into the peripheral countryside. By examining the concept of trade routes, the article contributes to the literature on urban-rural relations in African Studies and ‘inconspicuous globalisation’ by proposing a contrary perspective, where rural areas viewed as areas of consumption of imported products. It then rescales the globalization analysis by situating urban-rural relations at the heart of local and global interconnections. The article demonstrates that geographically peripheral places and actors have a capacity to influence the direction of the global trade route as they combine complementarities between the urban-rural continuum and topological continuity of networks from local to global. The global trade geography is profoundly influenced by what goes on in its inconspicuous tentacles in upcountry regions, such as the Uporoto Mountains, where the global trade route relies on the dynamism of local agriculture, which is increasingly merging with other livelihoods. This is exemplified by the complementarities between trade and agriculture in terms of livelihood, circulation of capital, urban-rural mobility, and links to global scales, which highlight the de-agrarianization process and the development of a mass consumption society.

Step towards elimination of Wuchereria bancrofti in Southwest Tanzania 10 years after mass drug administration with Albendazole and Ivermectin.

BackgroundLymphatic filariasis is a mosquito transmitted parasitic infection in tropical regions. Annual mass treatment with ivermectin and albendazole is used for transmission control of Wuchereria bancrofti, the infective agent of lymphatic filariasis in many African countries, including Tanzania.MethodologyIn a general population study in Southwest Tanzania, individuals were tested for circulating filarial antigen, an indicator of W. bancrofti adult worm burden in 2009 before mass drug administration commenced in that area. Seven annual rounds with ivermectin and albendazole were given between 2009 and 2015 with a population coverage of over 70%. Participants of the previous study took part in a follow-up activity in 2019 to measure the effect of this governmental activity.FindingsOne thousand two hundred and ninety nine inhabitants of Kyela district in Southwest Tanzania aged 14 to 65 years who had participated in the study activities in 2009 were revisited in 2010/11 and 2019. Among this group, the prevalence of lymphatic filariasis of the 14–65 years olds in 2009 was 35.1%. A follow-up evaluation in 2010/11 had shown a reduction to 27.7%. In 2019, after 7 years of annual treatment and an additional three years of surveillance, the prevalence had dropped to 1.7%, demonstrating successful treatment by the national control programme. Risk factors for W. bancrofti-infection were the occupation as farmer, male sex, and older age. Most infected individuals in the 2019 follow-up study already had a positive test for filarial antigen in 2009 and/or 2010/11.ConclusionsThis data supports the findings of the Tanzanian Neglected Tropical Disease Control Programme (NTDCP), who conducted Transmission Assessment Surveys and found an impressive reduction in the prevalence of LF in children. Our results complement this data by showing a similar decrease in prevalence of LF in the adult population in the same area. The elimination of LF seems achievable in the near future.

A new pseudosuchian archosaur, Mambawakale ruhuhu gen. et sp. nov., from the Middle Triassic Manda Beds of Tanzania.

The Manda Beds of southwest Tanzania have yielded key insights into the early evolutionary radiation of archosaurian reptiles. Many key archosaur specimens were collected from the Manda Beds in the 1930s and 1960s, but until recently, few of these had been formally published. Here, we describe an archosaur specimen collected in 1963 which has previously been referred to informally as Pallisteria angustimentum. We recognize this specimen as the type of a new taxon, Mambawakale ruhuhu gen. et sp. nov. The holotype and only known specimen of M. ruhuhu comprises a partial skull of large size (greater than 75 cm inferred length), lower jaws and fragments of the postcranium, including three anterior cervical vertebrae and a nearly complete left manus. Mambawakale ruhuhu is characterized by several cranial autapomorphies that allow it to be distinguished with confidence from all other Manda Beds archosaurs, with the possible exception of Stagonosuchus nyassicus for which comparisons are highly constrained due to very limited overlapping material. Phylogenetic analysis suggests that M. ruhuhu is an early diverging pseudosuchian, but more precise resolution is hampered by missing data. Mambawakale ruhuhu is one of the largest known pseudosuchians recovered to date from the Middle Triassic.

The Subcategorization of Derived Verbs in Kifipa

This paper aims at investigating Subcategorizations of derived verbs in Kifipa. Kifipa is a Bantu language spoken in south-west Tanzania by the people denoted to as Wafipa. Wafipa live in a bigger area between Lake Rukwa and Lake Tanganyika. Currently, the area is located in Rukwa region. Verbs are subcategorized differently in different languages. In isolating languages, verb subcategorization is a syntactic study while in Bantu languages verb subcategorization is a morphosyntactic study. In some languages derivation does not affect the subcategorization of verbs except passive while in other languages especially Bantu, derivation (verb extension) alters the subcategorization of basic verbs. The paper focuses on three morpho-syntactic aspects of derived verbs in Kifipa. The paper is guided by the theory known as Government and Binding theory and Burzio’s Generalization Principle in particular. Burzio’s generalization is the work of a linguist known as Luigi Burzio in 1986. Burzio's generalization deals with the organization of verb harmony, and how these verbs behave towards their arguments. In his theory, Burzio came up with a general classification of verbs. Qualitative approach and explanatory research design were employed in the analysis and presentation of data. A sample of six respondents from Matai and Singiwe villages were selected using snowball sampling technique on the basis of age and language ability. Data were collected through sentence questionnaires, grammaticality judgements and extraction from written materials. The findings reveal that Kifipa has three subcategories of derived verbs including the verbs which allow only a single argument, the verbs which allow the occurrence of two or three arguments and lastly the super transitive verbs which allow the occurrence of more than three arguments which is a result of the co-occurrence of two or more extension suffixes. Extension affixes in Kifipa affects the subcategory as they increase the number of arguments these extensions are applicative and causative verb extensions. On the other hand, extensions such as passive, reciprocal, stative and reflexive decrease the number of arguments while extension such as intensive does not affect the arguments of the verb.

HPV Type Distribution in HIV Positive and Negative Women With or Without Cervical Dysplasia or Cancer in East Africa.

BackgroundWomen living with HIV in sub-Saharan Africa are at increased risk to develop cervical cancer (CC), which is caused by persistent infection with 13 oncogenic human papilloma viruses (HR-HPVs). It is important to accurately identify and target HIV-positive women at highest risk to develop CC for early therapeutic intervention.MethodsA total of 2,134 HIV+ and HIV− women from South-West Tanzania were prospectively screened for cervical cancer and precancerous lesions. Women with cervical cancer (n=236), high- and low-grade squamous intraepithelial lesions (HSIL: n=68, LSIL: n=74), and without lesion (n=426) underwent high-resolution HPV genotyping.ResultsEighty percent of women who were diagnosed with HSIL or LSIL were living with HIV. Any lesion, young age, HIV status, and depleted CD4 T cell counts were independent risk factors for HPV infections, which were predominantly caused by HR-HPV types. While multiple HR-HPV type infections were predominant in HIV+ women with HSIL, single-type infections predominated in HIV+ CC cases (p=0.0006). HPV16, 18, and 45 accounted for 85% (68/80) and 75% (82/110) of HIV+ and HIV− CC cases, respectively. Of note, HPV35, the most frequent HPV type in HSIL-positive women living with HIV, was rarely detected as a single-type infection in HSIL and cancer cases.ConclusionHPV16, 18, and 45 should receive special attention for molecular diagnostic algorithms during CC prevention programs for HIV+ women from sub-Saharan Africa. HPV35 may have a high potential to induce HSIL in women living with HIV, but less potential to cause cervical cancer in single-type infections.

Performance Evaluation of Smallholder Irrigation Schemes in the Usangu Plains, South-West Tanzania

Abstract

Fertilisers differentially affect facultative and obligate parasitic weeds of rice and only occasionally improve yields in infested fields

Different fertilisers were field tested to investigate whether they (1) suppress the obligate parasitic weed Striga asiatica and the facultative parasitic weed Rhamphicarpa fistulosa, and (2) favour rainfed rice yields under parasitic weed infestation. Four years of experiments were conducted in southwest Tanzania, in a S. asiatica-infested rainfed upland and a R. fistulosa-infested rainfed lowland field. Treatments included sole mineral (NPK or Di-Ammonium Phosphate —DAP— plus urea), organic (cattle manure or rice husk), combinations of mineral and organic fertilisers and a no-fertiliser control. Fertilisers moderately suppressed the obligate parasite S. asiatica, but no correlations between infestation level and soil fertility status were observed. In the lowland field, fertilisers promoted the facultative R. fistulosa, in particular the ones that included organic components. Plant-available phosphorus, exchangeable potassium and soil organic matter content correlated with R. fistulosa infestation levels. Positive fertiliser effects on yields were found in both parasitic weed infested fields, except in years with high S. asiatica infestation levels. Rice husks alone and rice husks or manure combined with DAP and urea increased yields and soil fertility most. We conclude that fertilisation differentially affects the obligate and facultative parasitic weeds of rice systems; obligate parasites may be slightly suppressed, but facultative parasites may even be stimulated. Meanwhile, consistent rice yield increases under parasitic weed infested conditions cannot be obtained with fertiliser application when parasitic weed infestation levels are too high.

Place Names as Reservoirs of Rare Linguistic Data: the Bantu Locative Prefix i- in Southwest Tanzanian Toponyms

Abstract Since place names almost invariably outlive the speakers of a language, they are capable of retaining knowledge in connection with a specific locality. For instance a high percentage of toponyms in Southwest Tanzania with initial morpheme i- reveal this trait. This linguistic element is associated in this study with an old locative marker i-, a debated element in Bantu linguistics. Since previous studies locate the element only around the Great Lakes zone and South Africa, it is inferred from the findings presented here that the distribution of the morpheme may be spread in other Bantu speaking areas as well. This consideration recommends revisiting all the data that reflects the distribution of the morpheme i- and other morphemes, including data from other parts of Bantu speaking regions. In order to affirm the antiquity or the contemporaneity of the roles of this morpheme, these results recommend further morphosyntatic analysis to test the behaviour of the morpheme in specific languages spoken in the study area.

A new African Titanosaurian Sauropod Dinosaur from the middle Cretaceous Galula Formation (Mtuka Member), Rukwa Rift Basin, Southwestern Tanzania.

The African terrestrial fossil record has been limited in its contribution to our understanding of both regional and global Cretaceous paleobiogeography, an interval of significant geologic and macroevolutionary change. A common component in Cretaceous African faunas, titanosaurian sauropods diversified into one of the most specious groups of dinosaurs worldwide. Here we describe the new titanosaurian Mnyamawamtuka moyowamkia gen. et sp. nov. from the Mtuka Member of the Galula Formation in southwest Tanzania. The new specimen preserves teeth, elements from all regions of the postcranial axial skeleton, parts of both appendicular girdles, and portions of both limbs including a complete metatarsus. Unique traits of M. moyowamkia include the lack of an interpostzygapophyseal lamina in posterior dorsal vertebrae, pronounced posterolateral expansion of middle caudal centra, and an unusually small sternal plate. Phylogenetic analyses consistently place M. moyowamkia as either a close relative to lithostrotian titanosaurians (e.g., parsimony, uncalibrated Bayesian analyses) or as a lithostrotian and sister taxon to Malawisaurus dixeyi from the nearby Aptian? Dinosaur Beds of Malawi (e.g., tip-dating Bayesian analyses). M. moyowamkia shares a few features with M. dixeyi, including semi-spatulate teeth and a median lamina between the neural canal and interpostzygapophyseal lamina in anterior dorsal vertebrae. Both comparative morphology and phylogenetic analyses support Mnyamawamtuka as a distinct and distant relative to Rukwatitan bisepultus and Shingopana songwensis from the younger Namba Member of the Galula Formation with these results largely congruent with newly constrained ages for the Mtuka Member (Aptian–Cenomanian) and Namba Member (Campanian). Coupled with recent discoveries from the Dahkla Oasis, Egypt (e.g., Mansourasaurus shahinae) and other parts of continental Afro-Arabia, the Tanzania titanosaurians refine perspectives on the development of African terrestrial faunas throughout the Cretaceous—a critical step in understanding non-marine paleobiogeographic patterns of Africa that have remained elusive until the past few years.

Geology of the Ngualla carbonatite complex, Tanzania, and origin of the Weathered Bastnaesite Zone REE ore

The late Mesoproterozoic Ngualla carbonatite complex in southwest Tanzania comprises a central magnesiocarbonatite plug surrounded sequentially by an annular calcite carbonatite intrusion and fenitised felsic igneous country rocks. The calcite carbonatite contains phlogopite-rich (glimmerite) enclaves interpreted as fenitised wallrock xenoliths that have contributed silicate minerals, apatite and magnetite through dispersal and interaction, mainly within the calcite carbonatite magma. Ultramafic magmas were emplaced into the magnesiocarbonatite magma chamber before complete solidification of the magnesiocarbonatite. Contemporaneity allowed the two magmas to mingle. Rounded enclaves of hematite-barite in the magnesiocarbonatite are tentatively attributed to magma immiscibility. Following complete solidification of the calcite carbonatite, and overlapping late crystallization of the magnesiocarbonatite plug, late magnesiocarbonatite dikes and ultramafic dikes were emplaced, some of the latter as diatremes.Crystallization of ferroan dolomite in the magnesiocarbonatite plug resulted in residual magmatic concentration of Si, Ba, F and rare earth elements (REE), and crystallization of barite, quartz, calcite, fluorite and REE fluorocarbonates in miarolitic cavities. Concentrations of (total) rare earth oxides (TREO) in the unweathered magnesiocarbonatite are 1 to 2%. REE ore with 3 to 6% TREO resulted from weathering, during which CaCO3 and MgCO3 were leached from ferroan dolomite leaving a porous goethite-rich residue containing barite and bastnaesite, the latter having replaced primary synchesite. Other commodities with potential economic significance include phosphate and niobium, both of which were enriched by residual accumulation over the calcite carbonatite as a result of karstic weathering.Although weathering was a critical factor in the formation of REE ore at Ngualla, the primary proto-ore resulted mainly from in situ igneous processes. This genetic model is different from that used to account for many carbonatite-hosted ore bodies, which result from late-stage hydrothermal processes. Examples of hydrothermal rare earth deposits include those of the late Jurassic to early Cretaceous Chilwa Province, located 800 km south of Ngualla. The differences in ore-forming processes may reflect the relative ages of the carbonatites and a deeper level of erosion at Ngualla.

Long-term spatial-temporal trends and variability of rainfall over Eastern and Southern Africa

This study investigates the spatial-temporal trends and variability of rainfall within East and South Africa (ESA) region. The newly available Climate Hazards group Infrared Precipitation with Stations (CHIRPS-v2) gridded data spanning 37 years (1981 to 2017) was validated against gauge observations (N = 4243) and utilised to map zones experiencing significant monotonic rainfall trends. Standardised annual rainfall anomalies revealed the spatial-temporal distribution of below and above normal rains that are associated with droughts and floods respectively. Results showed that CHIRPS-v2 data had a satisfactory skill to estimate monthly rainfall with Kling-Gupta efficiency (KGE = 0.68 and a high temporal agreement (r = 0.73) while also preserving total amount (β = 0.99) and variability (γ = 0.8). Two contiguous zones with significant increase in annual rainfall (3–15 mm year−1) occurred in Southwest Zambia and in Northern Lake Victoria Basin between Kenya and Uganda. The most significant decrease in annual rainfall (− 20 mm year−1) was recorded at Mount Kilimanjaro in Tanzania. Other significant decreases in annual rainfall ranging between − 4 and − 10 mm year−1 were observed in Southwest Tanzania, Central-South Kenya, Central Uganda and Western Rwanda. CHIRPS-v2 rainfall product provides reliable high spatial resolution information on amount of rainfall that can complement sparse rain gauge network in rain-fed agricultural systems in ESA region. The observed spatial-temporal trends and variability in rainfall are important basis for guiding targeting of appropriate adaptive measures across multiple sectors.

The role of pre-existing Precambrian structures in the development of Rukwa Rift Basin, southwest Tanzania

In this study, Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) and aeromagnetic data are used to analyse the trends of pre-existing basement structures within the Rukwa Rift Basin. The NW-trending Rukwa Rift Basin on the western branch of the East African Rift System, southwest Tanzania, is developing on the NW-trending Paleoproterozoic Ubendian orogenic belt, a belt that experienced multiple orogenic collisions associated with subduction in Proterozoic time and comprises several distinct terranes bounded by faults or shear zones. The results obtained using magnetic edge enhancement (derivatives) methods highlight major magnetic domains identified based on their distinctive magnetic patterns in relation to geology and tectonic setting of the studied area. The results also highlight the Precambrian Chisi shear zone which trends in a NW-SE direction in the subsurface, below the Lake Beds Formation sedimentary succession of the Neogene Rukwa Rift Basin. The orientation of rift border faults and other major faults and their relationship with basement fabrics inferred from SRTM DEM and magnetic data trend mainly NW-SE, which is consistent with those of the NW-trending Paleoproterozoic Ubendian orogenic belt. Thus, Paleoproterozoic Ubendian orogenic belt structures have played a significant role on geometry and orientation of the Rukwa Rift Basin. These structures facilitated strain localisation within the border faults of the rift basin by exploiting the existence of inherited lithospheric heterogeneity. It can be concluded that the pre-existing faults and shear zones define a mechanical anisotropy in the basement of the Rukwa Rift Basin and facilitated the strain localisation within the border faults of the rift.