Search

The issues of climate change in Senegal have the potential of undermining sustainable development efforts if positive steps are not taken to respond to its adverse consequences. This study documents existing and available literature on impacts of climate change on Small and Medium Enterprises (SMEs) in semi-arid zones of Senegal. It is evident that there are significant negative impacts of climate on SMEs in Senegal. Loss of goods, low productivity and sales as well as loss of income are mainly observed by the small and medium enterprises due to the impacts of increased temperature, soil erosion and salinization, decrease of rainfall, frequency of extreme events on both supply and production processes. Despite this fact, there are limited adaptation and mitigation strategies to climate change at company or enterprise level in order to deal effectively with the changing climate. Ensuring Senegal's enterprises to develop more effective climate change adaptation and mitigation strategies, there is the need for the Senegalese government to support enterprises by providing the necessary resources such as credit, information, training for managers and employees on climate change adaptation strategies and technologies, and investing in climate resilient projects which will reduce significantly the adverse effects of climate change on business operations. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, temperatures are generally conducive to malaria transmission, and rainfall provides mosquitoes with optimal breeding conditions. The objective of this study is to assess the impact of future climate change on malaria transmission in West Africa using community-based vector-borne disease models, TRIeste (VECTRI). This VECTRI model, based on bias-corrected data from the Phase 6 Coupled Model Intercomparison Project (CMIP6), was used to simulate malaria parameters, such as the entomological inoculation rate (EIR). Due to the lack of data on confirmed malaria cases throughout West Africa, we first validated the forced VECTRI model with CMIP6 data in Senegal. This comparative study between observed malaria data from the National Malaria Control Program in Senegal (Programme National de Lutte contre le Paludisme, PNLP, PNLP) and malaria simulation data with the VECTRI (EIR) model has shown the ability of the biological model to simulate malaria transmission in Senegal. We then used the VECTRI model to reproduce the historical characteristics of malaria in West Africa and quantify the projected changes with two Shared Socio-economic Pathways (SSPs). The method adopted consists of first studying the climate in West Africa for a historical period (1950–2014), then evaluating the performance of VECTRI to simulate malaria over the same period (1950–2014), and finally studying the impact of projected climate change on malaria in a future period (2015–2100) according to the ssp245 ssp585 scenario. The results showed that low-latitude (southern) regions with abundant rainfall are the areas most affected by malaria transmission. Two transmission peaks are observed in June and October, with a period of high transmission extending from May to November. In contrast to regions with high latitudes in the north, semi-arid zones experience a relatively brief transmission period that occurs between August, September, and October, with the peak observed in September. Regarding projections based on the ssp585 scenario, the results indicate that, in general, malaria prevalence will gradually decrease in West Africa in the distant future. But the period of high transmission will tend to expand in the future. In addition, the shift of malaria prevalence from already affected areas to more suitable areas due to climate change is observed. Similar results were also observed with the ssp245 scenario regarding the projection of malaria prevalence. In contrast, the ssp245 scenario predicts an increase in malaria prevalence in the distant future, while the ssp585 scenario predicts a decrease. These findings are valuable for decision makers in developing public health initiatives in West Africa to mitigate the impact of this disease in the region in the context of climate change. [ABSTRACT FROM AUTHOR]

New and improved satellite sensors specially designed for vegetation monitoring have been launched in recent years; including the Moderate Resolution Imaging Spectrometer (MODIS) onboard Terra and Aqua, the Medium Resolution Imaging Spectrometer (MERIS) on the ENVISAT satellite, and VEGETATION onboard the Systeme Pour l'Observation de la Terre (SPOT) satellite. The aim of this paper is to evaluate two different vegetation indices of these new sensors; the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI). This is done by radiometric in situ measurements covering natural grass savanna in Senegal. Variations in the dynamic range of in situ NDVI was found caused by the differences in spectral response functions, MERIS NDVI characterized by the largest dynamic range. Both daily MERIS and MODIS NDVI mirrored accurately in situ measured NDVI (MERIS r² = 0.97 and MODIS r² = 0.96). VEGETATION NDVI (only available as ten-day composites) was found to be significantly lower than MODIS NDVI due to lower VEGETATION near-infrared (NIR) reflectance values. A good agreement between the NDVI/EVI relation from satellite and from in situ measured MODIS NDVI/EVI was found. This indicates an accurate atmospheric correction of the MODIS red, NIR, and blue spectral bands, also confirmed by in situ measured reflectances. EVI is sensitive to variations in blue band reflectance, and the consistency between EVI from the different sensors is reduced when compared to NDVI due to the different atmospheric correction schemes of the blue band. Thus, it is recommended that vegetation index cross-sensor algorithms should be based on NDVI over EVI. [ABSTRACT FROM AUTHOR]

This paper reports on the performance of using a multistage constructed wetland (CW) to treat municipal raw wastewater and an analysis of its suitability for agricultural irrigation. The pilot plant consists of two stages of vertical flow CWs plus one stage of a horizontal CW built in 2018 with different local materials at the Gaston Berger University Campus, Saint Louis (Senegal). Each CW stage is composed of several filters with different type of media (silex, granite, or river gravel), filtering media depths, and macrophytes (Phragmites and Typha). The physicochemical and microbiological indicators were monitored over six months at each bed inlet and outlet to evaluate the efficiency and achievements of the Senegalese, European, and WHO regulations/recommendations for disposal or reuse in irrigation. This study demonstrates the viability of this new multistage CW design to treat raw municipal wastewater and produce an effluent of good quality suitable for reuse in agriculture. The removal of organic matter, suspended solids, and nutrients was very high (>95% for SS, BOD5 and N-NH4+, >90% for COD and P-PO43−), as was the reduction of microbiological indicators (fecal coliform reduction >5 log units and helminth egg removal of 100%). First, trends related to the influence of design (the type of gravel, filter depth, and type of macrophyte), operational modes, and the CW treatment efficiency were determined. The use of non-crushed gravel and Typha spp. seemed to provide better removal rates. On the contrary, no differences were found between the use of silex or granite gravel. For the studied Senegalese conditions under dry and hot climates, the preliminary results indicate that no resting periods are necessary for vertical flow CWs (VFCWs), thus resulting in a reduction in construction and operation costs. The main outcome of our study is evidence that multistage CWs can provide robust, cost-effective treatments, as well as allow for safe water reuse, which is imperative in areas with severe water scarcity and endemic microbiological waterborne diseases. [ABSTRACT FROM AUTHOR]

Fungal communities associated with roots play a key role in nutrient uptake and in mitigating the abiotic and biotic stress of their host. In this study, we characterized the roots mycobiome of wild and cultivated pearl millet [Pennisetum glaucum (L.) R. Br., synonym: Cenchrus americanus (L.) Morrone] in three agro-ecological areas of Senegal following a rainfall gradient. We hypothesized that wild pearl millet could serve as a reservoir of endophytes for cultivated pearl millet. We therefore analyzed the soil factors influencing fungal community structure and whether cultivated and wild millet shared the same fungal communities. The fungal communities associated with pearl millet were significantly structured according to sites and plant type (wild vs cultivated). Besides, soil pH and phosphorus were the main factors influencing the fungal community structure. We observed a higher fungal diversity in cultivated compared to wild pearl millet. Interestingly, we detected higher relative abundance of putative pathotrophs, especially plant pathogen, in cultivated than in wild millet in semi-arid and semi-humid zones, and higher relative abundance of saprotrophs in wild millet in arid and semi-humid zones. A network analysis based on taxa co-occurrence patterns in the core mycobiome revealed that cultivated millet and wild relatives had dissimilar groups of hub taxa. The identification of the core mycobiome and hub taxa of cultivated and wild pearl millet could be an important step in developing microbiome engineering approaches for more sustainable management practices in pearl millet agroecosystems. [ABSTRACT FROM AUTHOR]

Peanuts are grown in both developed and developing countries, and their cultivation has been considerably expanded to semiarid and arid regions. In this study, we investigated the ROS-scavenging activity and bioactive composition of hydric stress-tolerant (BR1, Senegal 55,437, L7 Bege, F.M424B) and -susceptible peanut genotypes (LViPE-06, LGoPE-06 and Tatu). Peanut grains were examined for their fatty acid profile by GC-FID, tocopherol content by HPLC-FLD, phenolic composition by LC–ESI-LTQ-Orbitrap-MS, and for their ability to deactivate ROS (ROO·, HOCl, O2·− and OH·). All genotypes had the same fatty acid profile. The highest total tocopherol content was found in the drought-tolerant genotype BR1 (80.38 mg·100 g−1), which corresponded to nearly twofold that found in most peanut genotypes. BR1 grains showed the greatest capacity to deactivate ROO•, whilst LGoPE-06, F.M424B, BR1 and LViPE-06 grains were the most active against HOCl. The greatest OH• scavenging capacity was observed for Senegal 55,437 genotype (drought tolerant). LC–ESI-LTQ-Orbitrap-MS analysis detected a total of 26 polyphenols, including 2,6-dihydrobenzoic acid, 2,5-dihydroxybenzoic acid, protocatechuic acid-O-hexoside and catechin-O-hexoside, which were identified for the first time in unpeeled peanuts. To conclude, both drought-tolerant and -susceptible peanut genotypes did not have any significant influence on the content of fatty acids and tocopherols and ROS scavenging, although the drought-tolerant genotype BR1 stood out significantly from the others. [ABSTRACT FROM AUTHOR]

The article reports on the problems which beset inhabitants of deserts. According to the United Nations, about 80 million people live on lands which are already rendered useless because of erosion, salt encrustation, and vegetation change. Those whose are not dependent on agriculture for their subsistence flock to overcrowded cities to compete for food and jobs. This fact is best manifested by the drought that West African countries, namely Mauritania, Senegal, Upper Volta Niger, Chad, and Mali, endured from 1968 to 1973. The rampant dislocation of people in these localities emphasized the typically low rainfall in these regions.

Background: Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. Methodology/Principal Findings: A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes) involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961–2003). We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. Conclusion/Significance: Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends the identification of rainfall patterns favourable for RVFV amplification. Author Summary: Rift Valley fever (RVF) is a zoonotic disease that affects domestic livestock and humans. During inter-epizootic periods, the main infection mechanism is suspected to be through bites by infected mosquitoes, mainly of Aedes and Culex genera. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. This study brings mechanistic insight to explain why reported RVF outbreaks in Northern Senegal cannot be correlated directly to rainfall. This is done through the use of a rainfall-driven model of RVF vector populations that combines a hydrological model to simulate daily water variations of mosquito breeding sites, with mosquito population models capable of reproducing the major trends in population dynamics of the two main vectors of RVF virus in Senegal, Ae. vexans and Cx. poicilipes. Results show that RVF occurs during years when both species are present simultaneously in high densities. Simulations of inter-annual variations in mosquito populations successfully explained the dates of RVF outbreaks observed between 1961 and 2003. [ABSTRACT FROM AUTHOR]