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Invasive plants are establishing in many protected areas where use of synthetic herbicides is prohibited. We introduce a nature-based approach (NbA) as an alternative to controlling invasives. The integration of NbA into ecosystem conservation provides potential to suppress invasive plants, improve soil cover, increase the diversity of native plants, and ultimately ensure ecosystem sustainability.

Background: Masai Giraffes have declined dramatically in recent decades due to loss of habitat and illegal hunting. Hence, it is critically important that the epidemiology and etiology of so-called giraffe skin disease (GSD) is understood well.Aim: To assess the prevalence and histopathological characteristics of GSD in the Tarangire-Manyara Ecosystem (TME), northern Tanzania.Methods: The study used road transects to gather field information on GSD. Eighty-four giraffes were sighted by systematic random sampling in the six study sites. Examination of giraffes involved body distribution of lesions, severity of the lesions and whether they were associated with age and sex of the affected giraffes. Five giraffes with GSD were immobilized for tissue collection and histopathological analysis.Results: Prevalence among adults was 79%. Affected animals typically had 1-5 lesions which were mostly moderate and were predominantly observed on the forelegs. GSD positivity rate was higher among females versus males, whereas males had a higher rate of severe lesions and generally had more lesions than females. Calves showed no lesions. All tissue sections from five affected giraffes showed the presence of large quantities of fungal elements (hyphae and spores) that involved hair shafts and sub-cutaneous tissue after staining with Grocott Methenamine Silver as special fungal staining technique.Conclusions: Our findings suggest the involvement of fungal infection in GSD pathogenesis.Clinical relevance: We recommend further characterization of the lesions using modern molecular techniques and culture to identify primary and secondary or opportunistic etiologies, and the order in which the pathogens occur in the lesions.

Water bodies in Tanzania are experiencing increased siltation, which is threatening water quality, ecosystem health, and livelihood security in the region. This phenomenon is caused by increasing rates of upstream soil erosion and downstream sediment transport. However, a lack of knowledge on the contributions from different catchment zones, land-use types, and dominant erosion processes, to the transported sediment is undermining the mitigation of soil degradation at the source of the problem. In this context, complementary sediment source tracing techniques were applied in three Tanzanian river systems to further the understanding of the complex dynamics of soil erosion and sediment transport in the region. Analysis of the geochemical and biochemical fingerprints revealed a highly complex and variable soil system that could be grouped in distinct classes. These soil classes were unmixed against riverine sediment fingerprints using the Bayesian MixSIAR model, yielding proportionate source contributions for each catchment. This sediment source tracing indicated that hillslope erosion on the open rangelands and maize croplands in the mid-zone contributed over 75% of the transported sediment load in all three river systems during the sampling time-period. By integrating geochemical and biochemical fingerprints in sediment source tracing techniques, this study demonstrated links between land use, soil erosion and downstream sediment transport in Tanzania. This evidence can guide land managers in designing targeted interventions that safeguard both soil health and water quality.

This study provides a detailed assessment of land cover (LC) changes on the water balance components on data constrained Kikafu-Weruweru-Karanga (KWK) watershed, using the integrated approaches of hydrologic modeling and partial least squares regression (PLSR). The soil and water assessment tool (SWAT) model was validated and used to simulate hydrologic responses of water balance components response to changes in LC in spatial and temporal scale. PLSR was further used to assess the influence of individual LC classes on hydrologic components. PLSR results revealed that expansion in cultivation land and built-up area are the main attributes in the changes in water yield, surface runoff, evapotranspiration (ET), and groundwater flow. The study findings suggest that improving the vegetation cover on the hillside and abandoned land area could help to reduce the direct surface runoff in the KWK watershed, thus, reducing flooding recurring in the area, and that with the ongoing expansion in agricultural land and built-up areas, there will be profound negative impacts in the water balance of the watershed in the near future (2030). This study provides a forecast of the future hydrological parameters in the study area based on changes in land cover if the current land cover changes go unattended. This study provides useful information for the advancement of our policies and practices essential for sustainable water management planning.

Increasing demand for food production results in Land use and land cover (LULC) changes, which afflicts the provision of ecosystem services in high mountain areas. This work used time-series LULC a...

Background Current animal tracking studies are most often based on the application of external geolocators such as GPS and radio transmitters. While these technologies provide detailed movement data, they are costly to acquire and maintain, which often restricts sample sizes. Furthermore, deploying external geolocators requires physically capturing and recapturing of animals, which poses an additional welfare concern. Natural biomarkers provide an alternative, non-invasive approach for addressing a range of geolocation questions and can, because of relatively low cost, be collected from many individuals thereby broadening the scope for population-wide inference. Methods We developed a low-cost, minimally invasive method for distinguishing between local versus non-local movements of cattle using sulfur isotope ratios (δ34S) in cattle tail hair collected in the Greater Serengeti Ecosystem, Tanzania. Results We used a Generalized Additive Model to generate a predicted δ34S isoscape across the study area. This isoscape was constructed using spatial smoothers and underpinned by the positive relationship between δ34S values and lithology. We then established a strong relationship between δ34S from recent sections of cattle tail hair and the δ34S from grasses sampled in the immediate vicinity of an individual’s location, suggesting δ34S in the hair reflects the δ34S in the environment. By combining uncertainty in estimation of the isoscape, with predictions of tail hair δ34S given an animal’s position in the isoscape we estimated the anisotropic distribution of travel distances across the Serengeti ecosystem sufficient to detect movement using sulfur stable isotopes. Conclusions While the focus of our study was on cattle, this approach can be modified to understand movements in other mobile organisms where the sulfur isoscape is sufficiently heterogeneous relative to the spatial scale of animal movements and where tracking with traditional methods is difficult.

Problems associated with the invasiveness of exotic tree species such as Acacia mearnsii have increased recently causing vast damage in environment and economy worldwide. Sao Hill Forest Plantation...

Backgroundand research aim: In the anthropogenic landscapes where historically wildlife existed, there can be a potential for rewilding to reverse extinction. However, there is limited literature providing approaches to achieve successful rewilding. The current study aimed at providing empirical based methodological procedures for successful rewilding of the University of Dodoma (UDOM) and nearby degraded landscape by assessing past and current vegetation and large mammal species’ occurrence. Methodology: The past occurrence of mega-herbivores and their habitat was assessed using systematic literature survey, past vegetation maps and key informant interviews. EBSCOhost database and Google Scholar search engine were used for literature searching. A survey was conducted at UDOM area which is one of the remaining habitat patches in central Tanzania to examine present plant diversity. Results: The baseline vegetation map of 1960 indicated that the study area was mainly Savanna woodland. Literature suggested that anthropogenic activities resulted into Land-Use Land-Cover Changes (LULCC) leading into wild animals’ extirpation leaving remnant populations in the surrounding protected areas. While the key informant interviews verified local loss of mega-herbivores, field data collected at UDOM campus in 2022 indicated the vegetation transformation to bushland dominated by Dichrostachys cinerea. The area’s past vegetation composition was 33% grasses, 29% herbs, 21% shrubs and 17% trees while the current was 18% grasses, 42% herbs, 30% shrubs and 10% trees. Conclusion: The study revealed that central Tanzania hosted spectacular large mammal populations that interacted with the savanna which has recently been transformed to bushland. However, observed evidence on past existence of large mammals and recent elephants’ sightings at UDOM area indicate great potential for rewilding. Implication for conservation: Reconstructing historical information of ecosystems is crucial for successful rewilding. Such information can guide conservation efforts aiming at reversing extinction and reestablishing connectivity of large herbivore population across ecosystems.

Malignant Catarhal Fever (MCF), caused by a virus transmitted from asymptomatic wildebeest, is a lethal disease in cattle that threatens livestock-based livelihoods and food security in many areas of Africa. Many herd owners reduce transmission risks by moving cattle away from infection hot-spots, but this imposes considerable economic burdens on their households. The advent of a partially-protective vaccine for cattle opens up new options for disease prevention. In a study of pastoral households in northern Tanzania, we use stated preference choice modelling to investigate how pastoralists would likely respond to the availability of such a vaccine. We show a high probability of likely vaccine uptake by herd owners, declining at higher vaccine costs. Acceptance increases with more efficaceous vaccines, in situations where vaccinated cattle are ear-tagged, and where vaccine is delivered through private vets. Through analysis of Normalized Density Vegetation Index (NDVI) data, we show that the reported MCF incidence over 5 years is highest in areas where the mean and interannual varibility in vegetative greeness is relatively low and where herds sizes are smaller. Trends towards lower rainfall and greater landscape-level constraints on cattle movement suggest that MCF avoidance through traditional movement away from wildebeest will become more challenging and that demand for an MCF vaccine will likely increase.

Phosphorus (P) is an important nutrient required for plant growth. Land use influences concentration and bioavailability of P in agricultural soils. About 198 soil samples (0-30 cm soil depth) were collected from three land-use types (maize, paddy, and conserved areas) in Usangu basin located in Southern Highland Tanzania. The concentration of soil P determined were compared among different land-use types and locations. The total P (TP), complexed (Po), and bioavailable P (B-P) were measured. The concentration of TP and B-P was determined by acid digestion and Mehlich 3 method, respectivelly, The Po concentration in soil extract was obtained by subtracting B-P from TP. TP, B-P and Po concentration in collected soils samples were in range of; Total P (63.12-1350.9 mg/kg), Bioavailable P (0.52-49.87 mg/kg), and complexed P (62.60-1301.03 mg/kg). The cropping area had high TP but very low B-P, especially in paddy farming areas indicating cropping and associated activity decrease bioavailable P in agricultural soils. Furthermore, soils from cropping areas had higher Al, Fe, and Mg concentrations than conserved areas, which caused a substantial reduction in B-P due to increased P fixation and adsorption. It is important to note that converting natural land to farming land could potentially influence soil P dynamics thus affecting P bioavailability, crop productivity, and environmental safety.

The aim of this study was to assess the effects of varying water stress levels on morphological and physiological parameters of an invasive plant

Mosquitoes and the diseases they transmit are a global public health threat that affects most human populations. Mosquito abundances are strongly linked to the number of suitable larval habitats available. However, it is still not well understood how different land uses impact larval habitat quality in different parts of the world. We investigated links between land use practices and abundance of mosquito larvae in temporary ponds located in different land uses in a malaria expansion zone in Tanzania. Temporary ponds are often cited as important sources of mosquitoes but are also of substantial conservation concern being home to a unique fauna and flora. Often, they also have high socio-economic importance. Overall, encountered mosquito larval abundances were very low, both for the collected Anopheles gambiae s.l. and Culex quinquefasciatus. Although temporary ponds are important mosquito larval habitats in other parts of Africa, currently they are unlikely to be an important factor affecting the prevalence of mosquito borne diseases in the Manyara study region. Larval abundances in temporary ponds were higher in agricultural areas where more eutrophic conditions were found and minimal in residential areas. Overall, even though temporary ponds are often modified as rice paddies in the rainy season, they were in a good ecological condition and hosted a diverse assemblage of aquatic predators that likely prevented larval mosquitoes from reaching high densities. Maintaining this good condition by preventing pesticide and nutrient input as much as possible, can be important to prevent pond degradation that is likely to make these habitats more suitable for mosquitoes in the future.

Dietary studies in birds of prey involve direct observation and examination of food remains at resting and nesting sites. Although these methods accurately identify diet in raptors, they are time-consuming, resource-intensive, and associated with biases from the feeding ecology of raptors like

This study aimed to reconstruct the sedimentation rates over time and identify the changing sources of sediment in a major hydropower reservoir in Tanzania, the Nyumba ya Mungu (NYM). Fallout 210Pb measurements were used to estimate age of sediment deposits and broad changes in sedimentation rates were reconstructed. Sedimentation peaks were cross referenced to geochemical profiles of allogenic and autogenic elemental constituents of the sediment column to confirm a causal link. Finally, geochemical fingerprinting of the sediment cores and potential sources were compared using a Bayesian mixing model (MixSIAR) to attribute the dominant riverine and land use sources to the reservoir together with changes through recent decades. Reservoir sedimentation generally increased from 0.1 g cm−2 yr−1 in the lower sediment column to 1.7 g cm−2 yr−1 in the most recent deposits. These results correlated to changes in allogenic and autogenic tracers. The model output pointed to one of two major tributaries, the Kikuletwa River with 60.3%, as the dominant source of sediment to the entire reservoir, while the other tributary, Ruvu River, contributed approximately 39.7%. However, downcore unmixing results indicated that the latest increases in sedimentation seem to be mainly driven by an increased contribution from the Ruvu River. Cultivated land (CU) was shown to be the main land use source of riverine sediment, accounting for 38.4% and 44.6% in Kikuletwa and Ruvu rivers respectively. This study explicitly demonstrated that the integration of sediment tracing and dating tools can be used for quantifying the dominant source of sediment infilling in East African hydropower reservoirs. The results underscore the necessity for catchment-wide management plans that target the reduction of both hillslope erosion reduction and the sediment connectivity from hillslope source areas to rivers and reservoirs, which will help to maintain and enhance food, water and energy security in Eastern Africa.

Ecosystem and livelihood sustainability of small-scale farmers in Eastern Africa are often challenged by climate change and unsustainable land use practices. Little is known on the small-scale temporal processes of cropping systems in relation to long-term climatic conditions. To understand the climatic influence on the cropping patterns, and its implications to wildlife/elephant conservation, our study used a combination of time-series datasets on crop and climate as well as geo-spatial layers spanning more than three decades. To validate the information analyzed from secondary data, we carried out participatory observation and interviews, whereby about 5% of village households were selected along an altitudinal gradient of Rombo area, Tanzania. We generated land use change maps using Geographical Information System (ArcGIS 10.4) and used Spearman’s correlation analysis to assess the influence of rainfall, temperature, and crop yield on the observed longitudinal changes in the crop types and other land use patterns both within and across altitudinal gradients. We found that perennial crops like coffee and banana concentrated in upper agro-ecological zones, with a clear division line above 1230 masl while seasonal crops like maize and beans were mostly cultivated in lowlands (below 1230 masl). The results further showed that coffee yields significantly declined with higher average annual minimum temperatures over the last 16 years. Within the same time period, there was a disproportionate shift from coffee to seasonal crop cultivation such as maize and beans. Elephant numbers declined by about 38%, while human settlement area increased by 28% over the last 30 years. We conclude that changes in land use and shifts in climate and cropping patterns have important implications for elephant conservation and sustainability of the ecosystem in Rombo area, Tanzania.

The build-up of heavy metals (HM) in agricultural soils accelerates the HM uptake by plants, which could potentially affect food quality and food safety. Here we studied the status and bioaccumulation of HM from soils to plant parts (roots, stem, and grains) in Usangu agro-ecosystem-Tanzania. In total 68 soil samples and 42 rice plant samples from six irrigation schemes were studied. The concentrations of cadmium-Cd, chromium-Cr, copper-Cu, lead-Pb, zinc-Zn, nickel-Ni, and iron-Fe were determined to estimate accumulation, distribution, bioconcentration. Total soil HM concentration in soil and plant samples was determined by acid digestion. The concentration of HM in soils samples (in mg/kg) were Cr (4.58–42.76), Co (1.486–6.12), Fe (3513.56–12593.99), Zn (7.89–29.17), Cd (0.008–0.073), Cu (0.84–9.25), Ni (0.92–7.98), and Pb (1.82–18.86). The total HM concentration in plant samples were (in mg/kg) were Cu (5.18–33.56), Zn (57.03–120.88), Fe (963.51–27918.95), Mn (613.15–2280.98), Cd (4.3–17.46), Pb (0.01–28.25), Cr (12.88–57.34) and Ni (9.65–103.33). The concentration of HM in soil and plant parts was observed to vary among locations where high concentrations of HM were detected in stems and roots compared to grains. The ratio HM in plants and soil samples (bioconcentration) was higher than one for some sites indicating higher HM uptakes by plants leading to possible health risk to soil invertebrates, animals, and humans. The bioconcentration factor varied among schemes, with the highest values at Igalako and Mahongole, which could be caused by artisanal gold mining and mining quarry existed in the area. Therefore, steps are needed to reverse the situation to balance the HM in agricultural soils and plant tissues to be within acceptable limits., Heavy metal; Paddy farming; Bioconcentration factor; Health risk; Agro-ecosystem.

This review presents research evidence of climate change and anthropogenic impacts on the slopes of Mt. Kilimanjaro and its implications on water, food and energy production (WFE nexus). While there exist divided scholarly opinions on the impacts of climate change on the Mt. Kilimanjaro glacier, consistent decreases in precipitation amounts are evident throughout the existing literature. The 2050 projections indicate increases in the precipitation amounts by approximately 16–18%. However, it is also stated that there will be a concomitant increase in water deficit of about 71%, 27% and 1% in agriculture, hydropower and livestock production respectively. Despite a large number of researches on impacts of climate and anthropogenic pressure on WFE along Mt. Kilimanjaro slopes, there are still limited long-term, good-quality and high-resolution altitudinal precipitation, temperature records and observation network. Moreover, there is limited information on groundwater recharge areas and their stability under changing environment. It is not clear how the interdependence and interaction between climate change, irrigation, vegetation and river discharges affect groundwater recharge process. Also, there is scarce information on future land use/cover changes. Very limited studies focused on fog water deposition for Mt. Kilimanjaro forest and East Africa, despite its relevance as the water tower of the mountain streams. The review further highlights how both climate and anthropogenic impacts may affect ecosystem services in the region. There is a need for developing adaptive strategies for responding to climate change and anthropogenic impacts on the slopes of Mt. Kilimanjaro now and into the future.

The oribi (Bovidae: Antilopinae: Ourebiini: Ourebia ourebi [Zimmermann, 1783 ]) is a small antelope distributed widely across open woody grasslands of sub‐Saharan Africa (Goldspink, Holland, Sweet, & Stewart, 2002 ), especially in hilly open‐broadleaf savanna and primarily feeds on herbaceous vegetation (Monfort & Monfort, 1974 ). The species lives singly or in small groups with multiple males, yet long‐term pairing is frequently low (Adamczak & Dunbar, 2008 ; Arcese, 1994 ; Arcese, Jongejan, & Sinclair, 1995 ; Jongejan, Arcese, & Sinclair, 1991 ). Oribi are readily identifiable with a tan coat and whitish underbelly, large ears, a conspicuous black‐coloured preorbital glandular spot below the ear, long neck and long legs (Foley et al., 2014 ; Kingdon et al., 2013 ). Up to 13 subspecies have been described with one subspecies found in Serengeti National Park: O. ourebi cottoni .

As the influx of different invasive species and their spread to new areas increases, there is a need for a rigorous and relevant scientific evidence-based control and restoration (EBCR) approaches to inform practical decisions and policymaking. While evidence-based decision is gaining popularity in science and policy, its potential for transformative change especially in the management of invasive plant species remains unexplored. Control and restoration of areas invaded by invasive plant species in natural and protected ecosystems require such decisions. Here, we provide a framework to guide how EBCR can contribute to transformative change and we argue that upscaling existing EBCR practices in areas invaded by invasive plant species (especially in protected areas (PAs)) requires coalitions of interdisciplinary science, public, private, and civil society actors with a common goal. Since actors’ roles and stakeholder interactions are dynamic, to achieve durable impacts, the upscaling process must continually engage and involve actors, while maintaining a balance of incentives among them. Social and cultural dimensions of local communities as well as their indigenous and local knowledge need to be incorporated. Pathways to upscaling EBCR may involve leveraging adaptive governance, integrating successful initiatives and lessons into public policy and practices, or reinforcing governance and management-led change with private efforts. We identify general lessons from (complex) PAs for successful upscaling of EBCR and illustrate the components of our framework through a novel application of a nature-based approach (NbA) in PAs invaded by invasive plant species.

The agrochemicals and nutrient losses from farming areas such as paddy farming significantly dictate quality and eutrophication of the freshwater resource. However, how farming and land use pattern affect water qualities and eutrophication remain poorly understood in most African agro-ecosystems. The present study characterized how paddy farming influences water qualities and eutrophication in 10 irrigation schemes in Usangu agro-ecosystem (UA). About 42 water samples were sampled from intakes, channels, paddy fields, and drainages and analyzed for EC, Cl, P, NH

Soil fertility determines crop growth, productivity and consequently determines land productivity and sustainability. Continuous crop production exploits plant nutrients from soils leading to plant nutrient imbalance, thus affecting soil productivity. This study was conducted to monitor soil fertility status in soils of Usangu agro-ecosystem to establish management strategies. To assess soil fertility status in Usangu agro-ecosystem in Southern Highland Tanzania; 0–30 cm depth soil samples were taken for organic carbon, soil pH, N, P, Ca, K, Mg, S, Al, and micronutrients such as Zn, Mn, Cu, Fe, and Cr analyses by various established standard analytical methods. The results indicated most micronutrients were available in the deficient amount in many studied sites except for Fe and Mn, which were observed to be above optimum requirement. Based on critical levels established in other areas, 90 % of the soils were ranked as N, P, K, and Mg deficient. The micronutrients (Cu, Fe, and Zn) were inadequate in all soils resulting in limited crop growth and productivity. A high concentration of trace metals was detected in agricultural soils, this might affect plant nutrients availability and leading to environmental contamination affecting land productivity and sustainability. The study found that Usangu agro-ecosystem has deprived of soil fertility leading to poor crop growth and productivity. The authors recommend the addition of supplemental materials rich in plant nutrients such as inorganic fertilizer, manure, crop residues, and treated wastes to improve soil fertility for improved productivity and land sustainability., Plant nutrients; Paddy wetlands; Trace metals; Soil fertility; Land sustainability.

East African farming communities face complex challenges regarding food and feed productivity. Primary production systems are under stress, nutritional choices are changing and the relationship between development and agriculture is undergoing profound transformation. In the face of severe threat of soil erosion, East African agro-pastoral systems are now at a tipping point and there has never been a greater urgency for evidence-led sustainable land management interventions to reverse degradation of natural resources that support food and water security. A key barrier, however, is a lack of high spatial resolution soil health data wherein collecting such information is beyond conventional research means. This research tests whether bridging this data gap can be achieved through a coordinated citizen science programme. Accessible and portable technology is currently available in the form of hand-held soil scanners that can enable farmers to become citizen scientists empowered to collect data to establish research data bases that support critical landscape decisions. The aim of the work was to test the potential for using soil scanners as a tool for mapping whole community soil health characteristics, using soil organic matter as an indicator, down to farm-scale; a resolution that is beyond that achievable in conventional research, with the ultimate objective to deliver information that empowers stakeholders to create a sustainable community landscape plan.Key outcomes included:(1) A training document for the usage of the soil scanner that includes a list of potential problems and their solutions. Moreover, a training session was organised in the Tanzanian partner institution to build capacity for the continuation of the project, wherein local researchers were trained in the application of the ‘Agrocares’ soil scanner to support continuing community engagement.(2) Local farmers being provided an opportunity to circumvent traditional power and knowledge inequities. During the introductory meeting and field measurements, we noticed the development of locally-embedded scientific interests and skills that foster stronger community ownership and engagement in action research.(3) A high resolution soil organic matter and nutrient status dataset in small-catchment and community setting. The citizen science data contributes to soil process and hydrological understanding of East African landscapes, which besides direct contribution to the scientific understanding, also supports co-design of effective management solutions to the soil erosion and land degradation challenges.The inclusion of ‘big data’ digital data training and sharing platforms and has the potential to create more robust and better informed collective decision-making, as well as identifying key data gaps. Further it can expand the utility and applicability of existing techniques and data sets beyond the reach of conventional research. Challenges and opportunities for wider use of soil scanning technology by community groups are evaluated.

The dramatic increase in world population underpins current escalating food demand, which requires increased productivity in the available arable land through agricultural intensification. Agricultural intensification involves increased agrochemicals use to increase land productivity. Increased uses of agrochemicals pose environmental and ecological risks such as contamination and water eutrophication. Consequently, toxic metals accumulate in plant products, thus entering the food chain leading to health concerns. To achieve this study, secondary data from peer-reviewed papers, universities, and government authorities were collected from a public database using Tanzania as a case study. Data from Science Direct, Web of Science, and other internet sources were gathered using specific keywords such as nutrient saturation and losses, water eutrophication, potentially toxic metal (PTEs), and impact of toxic metals on soils, water, and food safety. The reported toxic metal concentrations in agro-ecosystem worldwide are linked to agricultural intensification, mining, and urbanization. Statistical analysis of secondary data collected from East African agro-ecosystem had wide range of toxic metals concentration such as; mercury (0.001–11.0 mg Hg/kg), copper (0.14–312 mg Cu/kg), cadmium (0.02–13.8 mg Cd/kg), zinc (0.27–19.30 mg Zn/kg), lead (0.75–51.7 mg Pb/kg) and chromium (19.14–34.9 mg Cr/kg). In some cases, metal concentrations were above the FAO/WHO maximum permissible limits for soil health. To achieve high agricultural productivity and environmental safety, key research-informed policy needs are proposed: (i) development of regulatory guidelines for agrochemicals uses, (ii) establishment of agro-environmental quality indicators for soils and water assessment to monitor agro-ecosystem quality changes, and (iii) adoption of best farming practices such as split fertilization, cover cropping, reduced tillage, drip irrigation to ensure crop productivity and agro-ecosystem sustainability. Therefore, robust and representative evaluation of current soil contamination status, sources, and processes leading to pollution are paramount. To achieve safe and sustainable food production, management of potential toxic metal in agro-ecosystems is vital.

Soil resources in parts of Tanzania are rapidly being depleted by increased rates of soil erosion and downstream sediment transport, threatening ecosystem health, water and livelihood security in the region. However, incomplete understanding to what effect the dynamics of soil erosion and sediment transport are responding to land-use changes and climatic variability are hindering the actions needed to future-proof Tanzanian land-use practices. Complementary environmental diagnostic tools were applied to reconstruct the rates and sources of sedimentation over time in three Tanzanian river systems that have experienced changing land use and climatic conditions. Detailed historical analysis of sediment deposits revealed drastic changes in sediment yield and source contributions. Quantitative sedimentation reconstruction using radionuclide dating showed a 20-fold increase in sediment yield over the past 120 years. The observed dramatic increase in sediment yield is most likely driven by increasing land-use pressures. Deforestation, cropland expansion and increasing grazing pressures resulted into accelerating rates of sheet erosion. A regime shift after years of progressive soil degradation and convergence of surface flows resulted into a highly incised landscape, where high amounts of eroded soil from throughout the catchment are rapidly transported downstream by strongly connected ephemeral drainage networks. By integrating complementary spatial and temporal evidence bases, this study demonstrated links between land-use change, increased soil erosion and downstream sedimentation. Such evidence can guide stakeholders and policy makers in the design of targeted management interventions to safeguard future soil health and water quality.

Knob wood (Zanthoxylum chalybeum - Rutaceae) is a medicinal plant species subject to heavy exploitation throughout its areas of occurrence in Sub-Saharan Africa. Despite that the tree has different values as a traditional herb, there is a gap in understanding its current distribution and anthropogenic threats in its range areas. This study aimed at mapping the distribution and anthropogenic threats facing Z. chalybeum tree in different land uses of Simanjiro area, northern Tanzania. The rates of threats such as debarking, branch cutting, uprooting and harvesting were observed to be high in grazing lands (GL) and farmlands (FL) (73% and 62% respectively) while least threats were observed in game controlled areas (GCA) and game open areas (OA) (39% and 40% respectively). Majority of trees observed had signs of debarking (51%) followed by debarking and branch cutting (20.6%), debarking and uprooting, (15.8%), debarking, branch cutting and uprooting (4.76%), whole tree cutting (4.76%) and branch cutting (3.17%). Conservation areas (i.e. hunting blocks within game controlled areas and game open areas) were found to have higher abundance of Z. chalybeum with detectable distribution pattern than other locations in Simanjiro area. The current observation in this study also shows that the rates of harvesting are increasing and harvesting methods used by community members are unsustainable. Regulatory approaches that promote sustainable harvesting of the species should be developed and implemented to reduce the impacts of over harvesting of the species on its population persistence. Promotion of cultivation and conservation of the species in farmland would help reduce the harvesting pressures in protected areas while providing access by the local community in their farms.