Sustaining indigenous Maasai Alalili silvo-pastoral conservation systems for improved community livelihood and biodiversity conservation in East African rangelands.

Alalili system is one among the fewest remnant African indigenous and local knowledge systems that is traditionally practiced by Maasai pastoral communities to conserve certain portions of rangeland resources such as pastures and water for subsequent grazing during dry seasons. Despite its existence, East African rangelands face diverse threats from tenure security, unsustainable practices, climate, and land-use change that are notably endangering the biodiversity, livelihoods, and ecosystems in the landscape. Like other indigenous conservation systems, the sustainability of Alalili systems is being threatened, as Maasai communities are in transition due to continuous socio-cultural transformations coupled with increased livestock and human populations. We aimed to capture and document the existing occurrence and potential of Alalili systems as a pathway to improve resilience and sustain both biodiversity conservation and community livelihoods in rangeland areas of northern Tanzania. A cross-sectional research design was applied with the adoption of both purposive and stratified random sampling techniques to distinctively characterize the Alalili systems by land use and tenure types. Our results identified the existence of both communal and private Alalili systems. Their sizes varied significantly across types (t = 4.4646, p < 0.001) and land uses (F = 3.806, df = 3, p = 0.0123). While many (82%) of these Alalili systems are found in the communal land, our observations show a re-practice of Alalili systems in the private land is considered largely a re-emerging strategy for securing pastures in the face of local and global change. More than half (73%) of Alalili systems were found within game-controlled areas with little representation (about 8%) in non-protected land. Therefore, their sustainability is threatened by anthropogenic and climatic pressures, making their persistence more vulnerable to extinction. We recommend mainstreaming these practices into core pasture production and management areas, facilitating their reinforcement into policy and practices.

Fish predation affects invertebrate community structure of tropical temporary ponds, with downstream effects on phytoplankton that are obscured by pesticide pollution.

Aquatic biota of tropical temporary ponds typically experience a wide range of stressors that can drive the structure and dynamics of natural communities. Particularly in regions with intense agricultural activity, aquatic biota may not only experience predation pressure but also stress from pesticides that inadvertently enter the ponds. We increasingly understand how these different sources of stress affect classic model taxa under controlled laboratory conditions, but how predators and pesticides may jointly affect pond invertebrate communities is still unclear, particularly for tropical systems. Here, we conducted an outdoor mesocosm experiment to study how fish predation combined with exposure to an environmentally relevant concentration of the commonly used insecticide cypermethrin (0.8 ng/L) affects the structure of invertebrate communities, and its potential effects on leaf litter decomposition and invertebrate grazing efficiency as measures of ecosystem functioning. A total of seven invertebrate taxa were recorded in the mesocosm communities. Fish predation effectively lowered the number of invertebrate taxa, with fish mesocosms being dominated by high densities of rotifers, associated with lower phytoplankton levels, but only when communities were not simultaneously exposed to cypermethrin. In contrast, cypermethrin exposure did not affect invertebrate community structure, and neither fish predation nor cypermethrin exposure affected our measures of ecosystem functioning. These findings suggest that predation by killifish can strongly affect invertebrate community structure of tropical temporary ponds, and that downstream effects on phytoplankton biomass can be mediated by exposure to cypermethrin. More broadly, we contend that a deeper understanding of (tropical) temporary pond ecology is necessary to effectively manage these increasingly polluted systems.

Environmental risks of a commonly used pyrethroid: Insights from temporary pond species of the Lake Manyara Basin, Tanzania.

Environmental risks posed by widespread pesticide application have attracted global attention. Currently, chemical risk assessments in aquatic environments rely on extrapolation of toxicity data from classic model species. However, similar assessments based on local species could be complementary, particularly for unusual living environments such as temporary ponds. Here, we carried out an environmental risk assessment (ERA) of a pyrethroid model compound, cypermethrin, based on local temporary pond species. First, we measured cypermethrin residue concentrations in rivers, irrigation canals and temporary ponds in the Lake Manyara Basin (LMB). Then, we estimated the environmental risks of cypermethrin by combining these data with acute toxicity data of three resident species across three trophic levels: primary producers (Arthrospira platensis), invertebrate grazers (Streptocephalus lamellifer) and fish (Nothobranchius neumanni). Furthermore, we compared the derived ERA to that obtained using toxicity data from literature of classic model species. Cypermethrin residue concentrations in contaminated systems of the LMB ranged from 0.01 to 57.9 ng/L. For temporary pond species, S. lamellifer was the most sensitive one with a 96 h-LC50 of 0.14 ng/L. Regardless of the assumed exposure concentration (0.01 and 57.9 ng/L), the estimated risks were low for primary producers and high for invertebrate grazers, both for local species as well as for classic model species. The highest detected cypermethrin concentration resulted in a moderate risk estimation for local fish species, while the estimated risk was high when considering classic fish models. Our results confirm that, at least for pyrethroids, ERAs with classic model species are useful to estimate chemical risks in temporary pond ecosystems, and suggest that complementary ERAs based on local species could help to fine-tune environmental regulations to specific local conditions and conservation targets.

Towards sustainability: Threat of water quality degradation and eutrophication in Usangu agro-ecosystem Tanzania.

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, NH4-N, NO3-N, TN, Zn, Cu, Ca, and Mg. We observed water pH ranging from 4.89 to 6.76, which was generally below the acceptable range (6.5-8.4) for irrigation water. NH4-N concentration was in a range of 10.6-70.0 mg/L, NO3-N (8.4-33.9 mg/L), and TN (19.1-21,104 mg/L). NH4-N increased along sampling transect (sampling points) from intakes (5.7-29.1 mg/L), channels (19-20 mg/L), fields (12.9-35.8 mg/L), and outflow (10.6-70.0 mg/L), the same trend were found for NO3-N and TN. The TP determined in water samples were in the range of 0.01 to 1.65 mg/L; where some sites had P > 0.1 mg/L exceeding the allowable P concentration in freshwater resource, thus indicating P enrichment and eutrophication status. The P concentration was observed to increase from intake through paddy fields to drainages, where high P was determined in drainages (0.02-1.65 mg/L) and fields (0.0-0.54 mg/L) compared to channels (0.01-0.13 mg/L) and intakes (0.01-0.04 mg/L). Furthermore, we determined appreciable amount of potentially toxic elements (PTEs) such as Cu, Pb, Cd and Cr in studied water samples. The high N, P, and PTEs in drainages indicate enrichment from agricultural fields leading to water quality degradation and contaminations (eutrophication). The study demonstrates that water quality in UA is degrading potentially due to paddy rice farming and other associated activities in the landscape. Thus, the current study recommends starting initiatives to monitor irrigation water quality in UA for better crop productivity, and improved quality of drainage re-entering downstream through the introduction of mandatory riparian buffer, revising irrigation practices, to include good agronomic practices (GAP) to ensure water quality and sustainability.

The effects of extreme climate on the invasive plant Gutenbergia cordifolia: implications for its future management in savannah ecosystems.

The aim of this study was to assess the effects of varying water stress levels on morphological and physiological parameters of an invasive plant Gutenbergia cordifolia. The assessment was conducted in the screenhouse at the Nelson Mandela African Institution of Science and Technology following a completely randomized design (CRD). Both morphological and physiological parameters were variable under water stress levels. While the maximum (159 cm) and minimum (9 cm) plant heights for G. cordifolia were observed under flood and drought water stress respectively, its maximum root collar diameter of 5 mm and the minimum of 1.3 mm were observed under moderate flood and drought water stress respectively. Generally, the number of leaves was highest under moderate flood stress (194 leaves/plant), and lowest under drought stress (13 leaves/plant). Similarly, the largest and smallest leaf surface area of 9 × 103 and 1 × 103mm2 were observed under flood and drought water stress respectively due to G. cordifolia's tendency to retain water when exposed to water stress through a reduction in number of leaves and leaf surface area when under drought stress condition. While a decrease in leaf chlorophyll was observed across water stress levels with the lowest chlorophyll levels of 0.02 under drought water stress, an increase in leaf anthocyanin levels (0.29 Abs g.DM-1) was observed particularly under flood stress due to increased chlorophyll breakdown and plants' water stress, respectively. This study informs that extreme climatic events such as excessive floods will likely facilitate invasions by G. cordifolia leading to decreased biotic resistance of native communities in savanna rangelands. Efforts to manage G. cordifolia's effects in a changing climate must therefore include the development of strategies and action plans that account for catastrophic events like floods and drought.

We are what we eat, plus some per mill: Using stable isotopes to estimate diet composition in Gyps vultures over space and time.

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 Gyps vultures. Our study set out to estimate diet composition in Gyps vultures informed by stable isotopes that provide a good representation of assimilated diet from local systems.We hypothesized that differences in Gyps vulture diet composition is a function of sampling location and that these vultures move between Serengeti National Park and Selous Game Reserve to forage. We also theorized that grazing ungulates are the principal items in Gyps vulture diet.Through combined linear and Bayesian modeling, diet derived from δ13C in Gyps vultures consisted of grazing herbivores across sites, with those in Serengeti National Park consuming higher proportions of grazing herbivores (>87%). δ13C differences in vulture feather subsets did not indicate shifts in vulture diet and combined with blood δ13C, vultures fed largely on grazers for ~159 days before they were sampled. Similarly, δ15N values indicated Gyps vultures fed largely on herbivores. δ34S ratios separated where vultures fed when the two sites were compared. δ34S variation in vultures across sites resulted from baseline differences in plant δ34S values, though it is not possible to match δ34S to specific locations.Our findings highlight the relevance of repeated sampling that considers tissues with varying isotopic turnover and emerging Bayesian techniques for dietary studies using stable isotopes. Findings also suggested limited vulture movement between the two local systems. However, more sampling coupled with environmental data is required to fully comprehend this observation and its implications to Gyps vulture ecology and conservation.

Managing invasive plants through a nature-based approach in complex landscapes.

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.

Pesticide sensitivity of Nothobranchius neumanni, a temporary pond predator with a non-generic life-history.

Pesticides are crucial to improve agricultural productivity, but often adversely affect surrounding aquatic systems and their fauna. To determine the environmental risk of pesticides, routine ecotoxicological tests are performed on several organisms, including standard fish models. However, these typically do not include fish species from variable habitats and with non-generic life-histories. In particular, inhabitants from temporary ponds such as annual killifish are conventionally understood to be resilient to natural stressors which could translate to higher pesticide resistance or, alternatively, trade-off with their resistance to pesticides and render them more sensitive than classic fish models. Using standard exposure tests, we assessed short-term toxicity effects of two commonly used pesticides, Roundup and cypermethrin, on the annual killifish Nothobranchius neumanni, and compared its sensitivity with that of classic fish models. For Roundup, we found a 72 h-LC50 of 1.79 ± 0.11 mg/L, which is lower than the values reported for zebrafish, medaka, fathead minnow and rainbow trout, suggesting that N. neumanni is more sensitive to the compound. The opposite was true for cypermethrin, with a 72 h-LC50 of 0.27 ± 0.03 mg/L. However, these LC50-values do not deviate strongly from those reported for other fish species, supporting earlier findings in the congeneric N. furzeri that the sensitivity of annual killifish to pollutants is similar to that of classic fish models despite their assumed robustness to environmental stress.

Prevalence and histopathological characterization of Masai Giraffe (Giraffa camelopardalis tippelskirchi) skin disease in Tarangire-Manyara ecosystem, Northern Tanzania.

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.

Soil fertility and land sustainability in Usangu Basin-Tanzania.

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.

Accumulation and bioconcentration of heavy metals in two phases from agricultural soil to plants in Usangu agroecosystem-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.

Land use patterns influence the distribution of potentially toxic elements in soils of the Usangu Basin, Tanzania.

Spatial distribution of Potentially Toxic Elements (PTEs) in agricultural soils in Usangu Basin (Mbeya Region)-Tanzania were conducted. The study included three land-use types (paddy farming, maize farming, and conserved community forest areas). About 198 soil samples were collected from November to December 2019 across contrasting land management schemes (Group I dominated by agricultural areas versus Group II dominated by residential and agricultural areas). Total (aqua regia extracts) and bioavailable (Mehlich 3 extracts) PTEs concentrations were analyzed. For Group I and II areas, total and bioavailable concentrations (mg/kg dry weight, mean values) of some PTEs were: chromium 1662 ± 5.2 µg/kg for Group I and 1307 ± 3.9 µg/kg for Group II (Total), 55.1 ± 37.1 µg/kg for Group I and 19.2 ± 21.6 µg/kg for Group II (bioavailable); and lead 5272 ± 1650 µg/kg for Group I and 6656 ± 1994 µg/kg for Group II (Total), 1870 ± 800 µg/kg for Group I and 1730 ± 530 µg/kg for Group II (bioavailable). Soil total PTEs such as cadmium and lead were generally lower in Group I areas than in Group II areas. The reverse scenario was observed for copper. Farming areas had high PTEs concentration than non-farming areas because of anthropogenic activities. Overall, soil total concentrations of Fe (99.5%), As (87%), Se (66%), and Hg (12%) were above Tanzanian Maximum Allowable Limits. This study provides essential baseline information to support environmental risk assessment of PTEs in Tanzanian agro-ecosystem.

Toxic metals in East African agro-ecosystems: Key risks for sustainable food production.

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.

Assessment of arsenic status and distribution in Usangu agro-ecosystem-Tanzania.

This study was conducted to assess arsenic (As) status and distribution in Usangu agroecosystem-Tanzania, including three land use. About 198 soil samples were collected in ten irrigation schemes in three land uses. Total and bioavailable As were determined by acid digestion (Aqua regia (AQ)) and Mehlich 3 method (M3) to estimate status, distribution and bioavailability. Arsenic concentration were variable among land use and irrigation schemes where total arsenic ranged 567.74-2909.84 µg/kg and bioavailable As ranged 26.17-712.37 µg/kg. About 12-16% of total arsenic were available for plant uptake. Approximately 86.53% of studied agricultural soils had total As concentration above Tanzania maximum allowable limit. Bioavailable As were lower compared to total As and were within the acceptable threshold. Total arsenic concentration were variable among schemes and higher values were observed in schemes which are highly intensified and mechanized. Thus, this study provides essential site specific preliminary baseline information for As status and distribution in agricultural soils to initiate monitoring and management strategies for increased land productivity and environmental safety.

Characterization of soil phosphate status, sorption and saturation in paddy wetlands in usangu basin-Tanzania.

Phosphorus (P) is a vital plant macronutrient required for plant growth which usually available in limited amount. P availability for plant uptake in highly weathered soil is controlled by soil erosion and high fixation. The availability of P applied from fertilizers depend on the soil pH, soil sorption capacity (PSC) and P saturation status (PSD), which determines P storage, losses, fixation, and additional P to be added with minimal loss to the environment. PSC and PSD are agro-environmental indicators used to estimate P availability and P loss to the environment. However, PSC and PSD of agricultural soils had been never studied in Tanzanian soils. This study was conducted to assess and estimate P availability, PSC and PSD and the risks of P losses in tropical soils from Usangu basin popular for paddy farming. In total, 198 soil samples from 10 paddy irrigation schemes were collected (November-December 2019) and analyzed for inherent P (PM3), metal oxides of Aluminium (Al M3), iron (Fe M3), and calcium (Ca M3) as main PSC and PSD determinant. The determined concentrations were in range of; P M3 014.9-974.69 mg/kg, Al M3 234.56-3789.36 mg/kg, Fe M3 456.78-2980.23 mg/kg, and Ca M3 234.67-973.34 mg/kg. Estimated PSCM3 ranged 5.62-34.85 mmol/kg with a mean value of 14.14 mmol/kg corresponding to high status, ensuring high P holding capacity for plant uptake. However, some soils had very low PSCM3 creating a risk of P loss to environment. Among soils, the estimated PSD M3 ranged from 0.01 to 17.57% and was below (<24%), indicating low P loss risks to surface and groundwater, however, some soils were observed to have PSDM3 above 15% which correspond to a critical degree of phosphate saturation of 25% in a watershed using oxalate extraction method. Therefore some sites were associated with high P loss to the environment, immediate and precautionary actions for sustainable P management to increase productivity, environmental safety and sustainability are needed to be in place.

Integrating stakeholders' perspectives and spatial modelling to develop scenarios of future land use and land cover change in northern Tanzania.

Rapid rates of land use and land cover change (LULCC) in eastern Africa and limited instances of genuinely equal partnerships involving scientists, communities and decision makers challenge the development of robust pathways toward future environmental and socioeconomic sustainability. We use a participatory modelling tool, Kesho, to assess the biophysical, socioeconomic, cultural and governance factors that influenced past (1959-1999) and present (2000-2018) LULCC in northern Tanzania and to simulate four scenarios of land cover change to the year 2030. Simulations of the scenarios used spatial modelling to integrate stakeholders' perceptions of future environmental change with social and environmental data on recent trends in LULCC. From stakeholders' perspectives, between 1959 and 2018, LULCC was influenced by climate variability, availability of natural resources, agriculture expansion, urbanization, tourism growth and legislation governing land access and natural resource management. Among other socio-environmental-political LULCC drivers, the stakeholders envisioned that from 2018 to 2030 LULCC will largely be influenced by land health, natural and economic capital, and political will in implementing land use plans and policies. The projected scenarios suggest that by 2030 agricultural land will have expanded by 8-20% under different scenarios and herbaceous vegetation and forest land cover will be reduced by 2.5-5% and 10-19% respectively. Stakeholder discussions further identified desirable futures in 2030 as those with improved infrastructure, restored degraded landscapes, effective wildlife conservation, and better farming techniques. The undesirable futures in 2030 were those characterized by land degradation, poverty, and cultural loss. Insights from our work identify the implications of future LULCC scenarios on wildlife and cultural conservation and in meeting the Sustainable Development Goals (SDGs) and targets by 2030. The Kesho approach capitalizes on knowledge exchanges among diverse stakeholders, and in the process promotes social learning, provides a sense of ownership of outputs generated, democratizes scientific understanding, and improves the quality and relevance of the outputs.

Tracking animal movements using biomarkers in tail hairs: a novel approach for animal geolocating from sulfur isoscapes.

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.

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.

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.

Can Cynodon dactylon Suppress the Growth and Development of the Invasive Weeds Tagetes minuta and Gutenbergia cordifolia?

Approaches to managing invasive plants is challenging, particularly in protected areas where conventional methods, such as chemical herbicide applications are limited. We studied the effects of varying densities of Cynodon dactylon on the growth and development of the invasive weeds Tagetes minuta and Gutenbergia cordifolia in northern Tanzania. We conducted pot and field plot experiments following a completely randomized block design that was replicated three times. Increasing densities of C. dactylon significantly reduced growth, leaf total chlorophyll, biomass and significantly increased leaf anthocyanin of both T. minuta and G. cordifolia invasives. Our results further showed that the critical density of C. dactylon to suppress the two invasive species is ≥ 8 plants/m2. We suggest that C. dactylon can successfully be used as an alternative eco-friendly and sustainable approach for managing invasive weeds, such as T. minuta and G. cordifolia. This management technique can additionally improve forage production and biomass for wild and domestic herbivores in the affected areas.

A nature-based approach for managing the invasive weed species Gutenbergia cordifolia for sustainable rangeland management.

BACKGROUND: The invasive weed species Gutenbergia cordifolia has been observed to suppress native plants and to dominate more than half of the entire crater floor (250 km2) in the Ngorongoro Conservation Area (NCA). As this species has been found to be toxic to ruminants it might strongly impact animal populations in this ecologically diverse ecosystem. Hence, a nature-based approach is urgently needed to manage its spread. We tested two Desmodium spp extracts applied to G. cordifolia and assessed the latter's germination rate, height, fresh weight and leaf total chlorophyll content after 30 days in both laboratory and screen house experiments. RESULTS: Seedling germination rate was halved by Desmodium uncinatum leaf extract (DuL), particularly under higher concentrations (≥75 %) rather than lower concentrations (≤62.5 %). Likewise, in both laboratory and screen house experiments, germination rate under DuL treatments declined with increasing concentrations. Seedling height, fresh weight and leaf total chlorophyll content (Chl) were also most strongly affected by DuL treatments rather than D. uncinatum root extract, Desmodium intortum leaf extract or D. intortum root extract treatments. Generally, seedlings treated with higher DuL concentrations were half as tall, had one-third the weight and half the leaf Chl content compared to those treated with lower concentrations. CONCLUSION: Our study shows a novel technique that can be applied where G. cordifolia may be driving native flora and fauna to local extinction. Our data further suggest that this innovative approach is both ecologically safe and effective and that D. uncinatum can be sustainably used to manage invasive plants, and thus, to improve rangeland productivity.