Search Results (9)

Background: In the Sahel, one of the largest semi-arid areas in the world, pastoral livestock is the main source of protein for the local population. The quantification of herbaceous biomass in the Sahelian rangelands is of major importance since it provides food for the livestock. The main method used to monitor the biomass consists of cutting, drying, and weighting it. However, indirect methods are available and allow a reliable biomass estimation. Methods: In this study, we developed a non-destructive method for estimating herbaceous biomass for the Sahelian rangelands based on measurements of its height and coverage. Results: Results show that the fit is better in the fenced area. The volume index (height × coverage) provides a better biomass prediction with relative differences between measured and predicted biomass of 11% in 2017 and 8% in 2019. Conclusions: Monitoring herbaceous biomass without destroying it is possible by measuring only its height and coverage. Full article

Objectives: The goal of this study was to evaluate the application of the short form of the International Physical Activity Questionnaire Survey (IPAQ-SF) in the rural Senegalese Fulani pastoralist population by combining quantitative and qualitative methods. Design and participants: For the quantitative method, 101 men completed the IPAQ-SF questionnaire measuring moderate, vigorous, and walking physical activity. Self-rated health, BMI, and sociodemographic variables were also collected. With regard to the qualitative methods, a total of 22 participants were recruited and interviewed. Four themes were addressed, including (i) physical activity (PA) and its definition, description, related experiences, and representations of social actors; (ii) PA and health; (iii) PA and sport; and (iv) the body and Fulani world of life (i.e., Pulaagu/Ndimaagu). Results: Sahelian herders have a high level of self-reported PA and a low amount of daily sitting time. The measure of PA as proposed by the IPAQ-SF is not adapted to the Senegalese Ferlo pastoralists, mainly because this scale gives too much importance to leisure-time PA, perceived as unproductive energy expenditure, which is factually and symbolically antinomic to the Fulani lifeworld. Thus, neither intense nor moderate PA is related to self-rated health. However, sedentary lifestyles are linked to self-rated health and, therefore, to mortality and morbidity in Fulani pastoralists. Finally, walking, which is the dominant PA during transhumance and herd surveillance, is related to BMI. It therefore represents a protective factor against the occurrence of overweight and associated chronic non-communicable diseases. Conclusion: The mixed method approach developed in this study has shown that the IPAQ-SF is not a valid measure of PA in the population of Fulani male herders from the Ferlo region, given that unproductive energy expenditure is incompatible with the Fulani way of life, which condemns excess and immoderation. Full article

The romance future and conditional tenses are the result of the grammaticalization of Latin periphrasis, mainly cantāre habeō. In some medieval Romance languages, including Catalan, two types of forms existed: synthetic forms (faré ‘I will do’) and analytical forms (fer-lo he ‘I will do it’). Analytical forms do not present univerbation and are thus less grammaticalized than synthetic forms. The present work aims to study the distribution of synthetic and analytical forms diachronically. A diachronic corpus (11th c.–16th c.) was compiled to serve this purpose. According to the syntactic restrictions of clitic placement, analytical forms could appear in the same syntactic environments than synthetic forms with postverbal pronouns (faré-lo ‘I will do it’). Therefore, only those contexts are analysed to assess the degree of grammaticalization. Some recent works point out that the grammaticalization of future and conditional was more advanced in the eastern languages of the Iberian Peninsula, such as Catalan, than in the western ones. The results from our corpus confirm these differences. In addition, the data show another grammaticalization process: the evolution of clitic placement towards a fixed preverbal position. Full article

Zoonotic pathogens are responsible for most infectious diseases in humans, with rodents being important reservoir hosts for many of these microorganisms. Rodents, thus, pose a significant threat to public health. Previous studies in Senegal have shown that rodents harbour a diversity of microorganisms, including human pathogens. Our study aimed to monitor the prevalence of infectious agents in outdoor rodents, which can be the cause of epidemics. We screened 125 rodents (both native and expanding) from the Ferlo region, around Widou Thiengoly, for different microorganisms. Analysis, performed on rodent spleens, detected bacteria from the Anaplasmataceae family (20%), Borrelia spp. (10%), Bartonella spp. (24%) and Piroplasmida (2.4%). Prevalences were similar between native and the expanding (Gerbillus nigeriae) species, which has recently colonised the region. We identified Borrelia crocidurae, the agent responsible for tick-borne relapsing fever, which is endemic in Senegal. We also identified two other not-yet-described bacteria of the genera Bartonella and Ehrlichia that were previously reported in Senegalese rodents. Additionally, we found a potential new species, provisionally referred to here as Candidatus Anaplasma ferloense. This study highlights the diversity of infectious agents circulating in rodent populations and the importance of describing potential new species and evaluating their pathogenicity and zoonotic potential. Full article

A major challenge faced by human societies is to promote development that truly makes difference for people without jeopardizing their environment. This is particularly urgent in developing countries where, despite decades of development programs, local populations often live under poverty thresholds. With this study, we participate in the ongoing debate about the necessary global revision of development theory and practice in the rural Sahel. We retrace the development trajectories in the Ferlo, the northern silvopastoral zone of Senegal. We highlight how development has evolved from the 1940s to the present, from centralized development action programs focused on hydraulic infrastructure to current polycentric development with growing environmental concerns. We highlight multi-scale events that have influenced the successive development paradigms in the area. Focusing on the past thirty years, we analyzed twenty-five environment and natural resource management-oriented projects, describing the evolution of their objectives and actions over time and identifying recurring flaws: redundancy, lack of synergy, and questionable relevance to local needs We put forth that a more resilient thinking-based development paradigm is necessary to guide the growing number of environment-oriented development actions, including the African Great Green Wall, for which massive investments are ongoing throughout Ferlo and across the Sahel. Full article

Mosquitoes are vectors of major pathogen agents worldwide. Population dynamics models are useful tools to understand and predict mosquito abundances in space and time. To be used as forecasting tools over large areas, such models could benefit from integrating remote sensing data that describe the meteorological and environmental conditions driving mosquito population dynamics. The main objective of this study is to assess a process-based modeling framework for mosquito population dynamics using satellite-derived meteorological estimates as input variables. A generic weather-driven model of mosquito population dynamics was applied to Rift Valley fever vector species in northern Senegal, with rainfall, temperature, and humidity as inputs. The model outputs using meteorological data from ground weather station vs satellite-based estimates are compared, using longitudinal mosquito trapping data for validation at local scale in three different ecosystems. Model predictions were consistent with field entomological data on adult abundance, with a better fit between predicted and observed abundances for the Sahelian Ferlo ecosystem, and for the models using in-situ weather data as input. Based on satellite-derived rainfall and temperature data, dynamic maps of three potential Rift Valley fever vector species were then produced at regional scale on a weekly basis. When direct weather measurements are sparse, these resulting maps should be used to support policy-makers in optimizing surveillance and control interventions of Rift Valley fever in Senegal. Full article

The greening in the Senegalese Sahel has been linked to an increase in net primary productivity, with significant long-term trends being closely related to the woody strata. This study investigates woody plant growth and mortality within greening areas in the pastoral areas of Senegal, and how these dynamics are linked to species diversity, climate, soil and human management. We analyse woody cover dynamics by means of multi-temporal and multi-scale Earth Observation, satellite based rainfall and in situ data sets covering the period 1994 to 2015. We find that favourable conditions (forest reserves, low human population density, sufficient rainfall) led to a rapid growth of Combretaceae and Balanites aegyptiaca between 2000 and 2013 with an average increase of 4% woody cover. However, the increasing dominance and low drought resistance of drought prone species bears the risk of substantial woody cover losses following drought years. This was observed in 2014–2015, with a die off of Guiera senegalensis in most places of the study area. We show that woody cover and woody cover trends are closely related to mean annual rainfall, but no clear relationship with rainfall trends was found over the entire study period. The observed spatial and temporal variation contrasts with the simplified labels of “greening” or “degradation”. While in principal a low woody plant diversity negatively impacts regional resilience, the Sahelian system is showing signs of resilience at decadal time scales through widespread increases in woody cover and high regeneration rates after periodic droughts. We have reaffirmed that the woody cover in Sahel responds to its inherent climatic variability and does not follow a linear trend. Full article

During the monsoon season, the spatiotemporal variability of rainfall impacts the growth of vegetation in the Sahel. This study evaluates this effect for the Ferlo basin in central northern Senegal. Relationships between rainfall, soil moisture (SM), and vegetation are assessed using remote sensing data (TRMM3B42 and RFE 2.0 for rainfall, ESA-CCI.SM for soil moisture and MODIS Leaf Area Index (LAI)). The principal objective was to analyze the response of vegetation growth to water availability during the rainy season using statistical criteria at the scale of homogeneous vegetation-soil zones. The study covers the period from June to September for the years 2000 to 2010. The surface SM is well correlated with both rainfall products. On ferruginous soils, better correlation of intra-seasonal variations and stronger sensitivity of the vegetation to rainfall are found compared to lithosols soils. LAI responds, on average, two to three weeks after a rainfall anomaly. Moreover, dry spells (negative anomalies) of seven days’ length (three days for SM anomaly) significantly affect vegetation growth (maximum LAI within the season). A strong and significant link is also found between total precipitation and the number of dry spells. These datasets proved to be sufficiently reliable to assess the impacts of rainfall variability on vegetation dynamics. Full article

Climatic stress and anthropogenic disturbances have caused significant environmental changes in the Sahel. In this context, the importance of soil is often underrepresented. Thus, we analyze and discuss the interdependency of soil and vegetation by classifying soil types and its woody cover for a region in the Senegalese Ferlo. Clustering of 28 soil parameters led to four soil types which correspond with local Wolof denotations: Dek, Bowel, Dior and Bardial. The soil types were confirmed by a Non-metric Multidimensional-Scaling (NMDS) ordination and extrapolated via a Random Forest classifier using six significant variables derived from Landsat imagery and a digital elevation model (out-of-bag error rate: 7.3%). In addition, canopy cover was modeled using Landsat and a Reduced-Major-Axis (RMA) regression (R² = 0.81). A woody vegetation survey showed that every soil type has its own species composition. However, 29% of Bowel regions are deforested (i.e., degraded) and interviews revealed extensive environmental changes and a strong decline and local extinction of woody species. The differences between the soil types are significant, showing that vegetation changes (i.e., degradation and greening), resilience to climatic stress and human activities largely depend on soil properties. We highlight that spatial heterogeneity is an important aspect when dealing with environmental changes in the Sahel, and local knowledge can be well used to classify spatial units by means of public Earth observation data. Full article