Sudanian Zone Research Articles

Spatial distribution and impacts of climate change on Milicia excelsa in Benin, West Africa

African teak (Milicia excelsa (Welw.) C.C. Berg) is an endangered multi-use species. Understanding the impact of climate change on the distribution of this species may improve the ability to anticipate or recognize its decline or expansion and to take appropriate conservation measures if necessary. Ecological niche modeling was projected in geographical space to study the current and future distribution of M. excelsa in Bénin. MaxEnt was used to estimate the potential geographic distribution of the species under two Representative Concentration Pathways (RCP). Miroc 5 summaries and two RCP 4.5 and RCP 8.5 scenarios were used as predictor variables for projections of the geographic potential of this species. The performance of the model was assessed by the area under the curve (AUC), true skill statistics (TSS) and partial receiver operating characteristics (Partial ROC). From the results, M. excelsa was more a secondary species in the Guinean climatic zone and part of the Sudanian-Guinean and Sudanian climatic zone. The projections show a significant decrease in suitable habitats for the species from the two RCP scenarios. Only a part of the Guinean climatic zone remained suitable and few protected areas will conserve in situ M. excelsa. For the sustainable conservation of M. excelsa, it is essential to strengthen the protection of sacred forests located in the Guinean climatic zone.

Improving sorghum productivity under changing climatic conditions: A modelling approach

Climate variability and change will have far reaching consequences for smallholder farmers in sub-Saharan Africa, the majority of whom depend on agriculture for their livelihoods. Crop modelling can help inform the improvement of agricultural productivity under future climate. This study applies the Agricultural Production Systems sIMulator (APSIM) to assessing the impacts of projected climate change on two (early and medium maturing) sorghum varieties under different management practices. Results show high model accuracy with excellent agreement between simulated and observed values for crop phenology and leaf number per plant. The prediction of grain yield and total biomass of an early maturing variety was fair RMSEn (22.9 and 23.1%), while that of the medium maturing was highly accurate RMSEn (14.9 and 11.9%). Sensitivity analysis performed by changing the calibrated variables of key plant traits in the model, showed higher significant yield change by + or - 10 % changed in radiation use efficiency, (RUE), coefficient extinction (Coeff_ext) and Phyllocron (Phyllo) for early maturing variety while + or - 10 % changed in phyllochron and RUE showed a significant yield change for the medium maturing variety. Under climate change scenerios using RCP 8.5, the simulated yield for the early–maturing variety revealed high inter-annual variability and potential yield loss of 3.3% at Bamako and 1% at Kano in the near-future (2010–2039) compared to baseline (1980–2009). The mid-century (2040–2069) projected yield decline by 4.8% at Bamako and 6.2% at Kano compared to baseline (1980–2009). On the contrary, the medium maturing variety indicated significantly yield gain with high yielding potential in both climate regimes compared to the baseline period (1980–2009). The simulated grain yield increased by 7.2% at Bamako and 4.6% at Kano, in the near-future (2010–2039) while in the mid-century (2040–2069) projected yield increase of 12.3% and 2% at Bamako and Kano compared to baseline (1980–2009). Adaptation strategies under climate change for varying sowing dates in the near-future (2010–2039, indicated that June sowing had a higher positive yield gained over July and August sowing for early maturing variety; July sowing simulated positive gained by 5 -11% over June and August sowing for medium maturing variety in both locations. Similarly, under the mid-century (2040–2069), among the sowing dates and in both locations, June sowing indicates lowest negative yield change over July and August sowing for early maturing variety. However, for medium maturing variety, July sowing had the highest yield gain of 16% over June and August sowing at Bamako and June highest positive yield gained of 11.4% over July and August at Kano. Our study has, therefore, demonstrated the capacity of APSIM model as a tool for testing management, plant traits practices and adoption of improved variety for enhancing the adaptive capacity of smallholder farmers under climate change in the Sudanian zone of West Africa. This approach offers a promising option to design more resilient and productive farming systems for West Africa using the diverse sorghum germplasm available in the region.

English

Pterocarpus erinaceus is a popular tree for medicinal and fodder uses in the Sudano-Sahelian belt of West Africa. It is also used for its wood. P. erinaceus is one of the most exploited tree species in many countries in West Africa. Planks and logs have been exported towards the South-West Asian countries for ten years. This paper analysed the demographic structure, the ecological characteristics of natural stands of P. erinaceus and level of human pressure they suffer in two agro-ecological zones of Burkina Faso and Niger. Transects were installed in four  forests of which two  were in the Sahelian zone of Niger and two were in the Sudan region of Burkina Faso. Measurements and observations focused on the dendrometric parameters, soil type, vegetation type and the presence of termite mound. The traces of debarking and pruning were noted. Trenching traces have been categorized into 3 classes according to their intensity. The Sudanian zone shows higher densities than the Sahelian zone. The largest individuals of P. erinaceus (the mean diameter and the highest average height) are observed in the W regional park (57.7 ± 18.6 cm and 10.8 ± 2 m) although this park belongs to the Sahelian zone. In all areas, distribution of diameter classes are bells, characteristics of aging stands with predominance of older individuals. Dendrometric characteristics vary according to the agro-ecological zones, soil type and vegetation. Twenty-one percent of P. erinaceus inventoried in the Sahelian zone and 13% in Sudanian area are close to an anthill. P. erinaceus is a species of Sahelo-Sudanese areas, analysis of its demographic structure shows that individuals of small diameter are very poorly represented in all forests. The species is exploited much more in Sahelian zones for feed supplements. The soil type and vegetation type influence the growth of P. erinaceus. Indeed, the strongest individuals were observed on soil clay loam, sandy loam soil and woodland.   Key word: Pterocarpus erinaceus, demographic characteristics, Sahelian and Sudanian zones, Niger, Burkina Faso. &nbsp

English

Migration to and sedentarization in the sub-humid zone of Burkina Faso has become a major adaptation measure of Sahelian pastoralists to the severe droughts and in response to a rapidly changing socio-economic environment. This study is aimed at assessing livelihoods and livestock husbandry practices as a consequence of pastoralist sedentarization. The study sites were located in the Sudano-Sahelian and Sudanian zone of Burkina Faso. Findings revealed that severe Sahelian droughts of 1973/4 and 1983/4 led to massive migration and sedentarization of Sahelian pastoralists to their current locations in the sub humid zones. Since then, the sedentarized pastoralists have diversified their livelihood strategies in which livestock keeping and small-scale crop production play a central role. As the study sites are close to urban areas, a market-oriented local dairy production has also been developing. Overall, the total annual revenue of the sedentarized households and the size of their cattle herd have increased in tandem with the time they have been sedentarized. However, there are still some constraints and challenges such as restricted access to valuable pasture areas during the rainy season and recurrent herder-farmer conflicts that need to be addressed to strengthen the livelihoods of the sedentarized pastoralists. Key words: Pastoralism, livelihood diversification, sedentarization, sub-humid zone, West Africa. &nbsp

Aboveground biomass allometric equations and distribution of carbon stocks of the African oak (Afzelia africana Sm.) in Burkina Faso

The significant role of tropical forest ecosystems in the global carbon budget has increased the need for accurate estimates of tropical forest biomass. The lack of large-scale biomass allometric equations hampers the understanding of the spatial distribution of tree biomass and carbon stocks and their influencing factors in West Africa. This study aimed to develop allometric equations to estimate aboveground biomass of African oak (Afzelia africana Sm.) in Burkina Faso and to analyze factors affecting the variability of tree biomass and carbon storage. Sixty individual trees were destructively sampled in four protected areas along two climatic zones. In each climatic zone, log–log models were tested and fitted to each aboveground biomass component and to the total aboveground biomass. Carbon content in tree aboveground components was evaluated using the ash method. All validated equations showed good fit and performance with high explained variance. Allometric equations differed between the Sudano-sahelian zone and the Sudanian zone, except for leaf biomass equations. Both biomass allocation and carbon content varied significantly between tree components but not between climatic zones. Carbon content in tree components followed the patterns of biomass allocation with branches accounting for the highest proportion. In the two climatic zones, carbon contents were 50.18–52.62% for leaves, 54.78–54.94% for stems and 54.96–55.99% for branches. Dry biomass ranged from 509.05 to 765.56 kg tree−1 at site level and from 620.21 to 624.48 kg tree−1 along climatic zones. Carbon content varied from 53.90% in the Sudano-sahelian zone to 54.39% in the Sudanian zone. This study indicated that climate does not influence aboveground biomass production and carbon sequestration of Afzelia africana along the Sudano-sahelian and the Sudanian climatic zones of Burkina Faso. Future studies on climate–growth relationships should contribute to better understanding climate effects on biomass production and carbon storage.

IMPACT OF LAND USE AND LAND USE HISTORY ON FRUITS PRODUCTION OF VITELLARIA PARADOXA (SHEA TREE) ACCORDING TO AGROCLIMATIC ZONES IN MALI (WEST AFRICA)

To understand how various factors influence phenological patterns like fruit production and the extent of phenological variability as survival strategy in different environments, fruit production of shea trees was studied in different agroclimatic zones (North Sudanian, South Sudanian and North Guinean) in Mali. Three sites were selected for this study and in each site; two stands (field and fallow) were concerned. For each stand, three “land use history or land management" i.e. new fields/fallows (1-5 years), medium (6-10 years) and old (10 years) were considered and permanent plots of 0.25 ha were established. 60 adult shea trees (DBH) ≥ 10 cm) were selected by site and monitored for fruit production assessment. The nested analysis of variance on the yield showed a significant site effect and significant effect of land use history within stand. However, stand effect within site was not significant. Factors like site and land management (land use history) appear to be determinant for fruit production of V. paradoxa. The site of Mperesso in the South Sudanian zone showed the highest fruit mean yield (11 kg/tree), significantly higher than the fruit mean yield observed at Daelan (7 kg/tree) in the North Sudanian zone and that observed at Nafégué (6 kg/tree) in the North Guinean zone. For field stand, old fields showed highest mean yield in all sites. For fallow stand, old fallows showed the lowest mean yield in most of cases. Different pattern was observed between field and fallow stands regarding the effect of land management. More fields are aged, more they influence positively fruit production whereas more fallows are aged, and more they influence negatively fruit production. This study highlighted the importance of land management practices and therefore, any domestication program to be successful should consider the potential effect of management practices.

Agroforestry parkland profiles in three climatic zones of Burkina Faso

Agroforestry plays an important role in food security and farmer’s resilience to climate change and variability in West Africa. However agroforestry parkland profile in the climatic zone in Burkina Faso are not well known. Therefore, agroforestry parkland profiles in three climatic zones of Burkina Faso were studied. Thirty (30) farmlands in each climatic zone representing about 35 ha were randomly selected on which systematic woody species inventory and dendrometry data collection was undertaken. Diameter classes’ distribution and agroforestry parkland typologies using Importance Value Index analysis were also done. The results showed 42, 31 and 34 woody species respectively in Sudanian, Sudan-Sahel and Sahel strict zones with corresponding density of 37, 30 and 35 trees/ha. Agroforestry parklands in Sudan-Sahel zone appeared to be unstable compared with the two others climatic zones. Mono-woody species parkland of Vitellaria paradoxa was observed in the Sudanian zone while multi-woody species parklands were observed in the Sudan-Sahel and Sahel strict zones. Both the density of trees/ha and the number of species constituting the agroforestry parklands have a direct impact of carbon sequestration potential. Taking in account agroforestry parklands profile is therefore determinant in evaluating smallholders’ farmers in potential benefit from carbon market in each climatic zone.Keywords: Parkland typology, woody species, density, smallholders.

On-farm practices, mapping, and uses of genetic resources of Kersting’s groundnut [Macrotyloma geocarpum (Harms) Maréchal et Baudet] across ecological zones in Benin and Togo

Enhancing orphan crops productivity in developing countries is of paramount importance to providing quality diets to the growing population as well as resilience options to smallholder farmers in order to adapt to climate change. However, the status of genetic resources diversity and the utilisation patterns of many orphan crops have been poorly investigated to inform breeding programs and management strategies. In this study, we assembled Kersting’s groundnut diversity, associated farmers’ knowledge and production systems across three ecological zones in Benin and Togo. We collected data through focus group discussions in 43 villages. In addition, semi-structured interviews were conducted with 300 farmers. Four cell analyses was performed using cropping areas and number of Kersting’s groundnut farmers as criteria. We conducted a comparative analysis of the Kersting’s groundnut utilisations and production systems across ecological zones. In total, 308 accessions of Kersting’s groundnut were collected using farmers’ criteria such as grain colour, grain size, maturity time, yield potential, medicinal properties and marketability. Farmers grouped the accessions into five landraces based solely on grain colour. All landraces were cultivated in the Sudanian zone while only three of them were found in the Guinean and Sudano-Guinean zones. Most of these landraces were produced by a few farmers on small cropping areas. The choice of landraces for production depended on local intention for production and different use categories across ecological zones. Up to 46.80% of decrease in cropping areas was observed in most zones due to specific production bottlenecks such as drought and diseases. We discuss our findings and suggest tailored actions including effective in situ and ex situ conservation strategies, germplasm collection and characterization in other countries where the crop is produced, development of new cultivars with farmers’ preferred traits and enhancement of the genetic base of the species.

Assessing the Impact of Climate Variability on Wildfires in the N’Zi River Watershed in Central Côte d’Ivoire

This study evaluates the impact of climate variability on wildfire regime in the N’Zi River Watershed (NRW) in central Côte d’Ivoire. For that purpose, MODIS active fire and monthly burned area data are used to evaluate wildfire occurrence, impacts and trends. Wildfire data are compared to past trends of different climatic parameters extracted from long-term meteorological records. Generalized additive models and Spearman correlations are used to evaluate the relationships between climate variables and wildfire occurrence. Seasonal Kendall and Sen’s slope methods were used for trend analysis. Results showed that from 2001 to 2016, 19,156 wildfire occurrences are recorded in the NRW, of which 4443 wildfire events are observed in forest, 9536 in pre-forest, and 5177 in Sudanian zones. The burned areas are evaluated at 71,979.7 km2, of which 10,488.41 km2 were registered in forest, 33,211.96 km2 in pre-forest, and 28,279.33 km2 in Sudanian zones. A downward trend is observed in fire records. The results indicates a strong correlation between some climatic variables and wildfire regime in this ecoregion. These correlations can be used to develop models that could be used as prediction tools for better management of fire regimes and support decision-making in the NRW.

Traditional knowledge regarding edible insects in Burkina Faso

BackgroundInsects play an important role as a diet supplement in Burkina Faso, but the preferred insect species vary according to the phytogeographical zone, ethnic groups, and gender. The present study aims at documenting indigenous knowledge on edible insects in Burkina Faso.MethodsA structured ethno-sociological survey was conducted with 360 informants in nine villages located in two phytogeographical zones of Burkina Faso. Identification of the insects was done according to the classification of Scholtz. Chi-square tests and principal component analysis were performed to test for significant differences in edible insect species preferences among phytogeographical zones, villages, ethnic groups, and gender.ResultsEdible insects were available at different times of the year. They were collected by hand picking, digging in the soil, and luring them into water traps. The edible insects collected were consumed fried, roasted, or grilled. All species were indifferently consumed by children, women, and men without regard to their ages. A total of seven edible insect species belonging to five orders were cited in the Sudanian zone of Burkina Faso. Macrotermes subhyalinus (Rambur), Cirina butyrospermi (Vuillet, 1911), Kraussaria angulifera (Krauss, 1877), Gryllus campestris (Linnaeus, 1758), and Carbula marginella (Thunberg) (35.66–8.47% of the citations) were most cited whereas Rhynchophorus phoenicis (Fabricius, 1801) and Oryctes sp. (3.41–0.27%) were least cited. Cirina butyrospermi was most cited in the South Sudanian zone, whereas Macrotermes subhyalinus and Kraussaria angulifera were most cited in the North Sudanian zone but were cited in all nine villages. Cirina butyrospermi was preferred by Bobo, Guin, Sambla, Senoufo, and Turka ethnic groups whereas Macrotermes subhyalinus was preferred by Fulani, Mossi, and Toussian ethnic groups. Oryctes sp. was cited only by the Toussian.ConclusionA diversity of edible insects was consumed in both the South and North Sudanian zone of Burkina Faso with significant differences in species preferences according to phytogeographical zones, villages, ethnic groups, and gender.

Impacts of Land Use and Cover Changes on Transhumant Pastoralism in Sudanian Zones of Burkina Faso, West Africa

This research aimed to investigate how the rapid land use and cover changes is affecting pastoral resources and practices within Kompienga province in Sudanian zone of Burkina Faso. To achieve this aim, Landsat images data of years 1989, 2001, 2013 and 2015 were retrieved and analysed. Images were acquired following the path 193 and row 52, from Landsat-5 Thematic Mapper (TM), Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-8 Operational Land Imager (OLI). Images processing were done using 350 training sample for both; the purpose of supervised classification and accuracy assessment. Random Forest Algorithm (RFA) procedures in R-Software (version 3.3.2) were used for images classification. Furthermore, survey data were collected through group discussions and individual interviews with a 271 head of household respondents (pastoralists and agro-pastoralists) to investigate respondents’ perceptions on land uses and covers changes and its impacts on their pastoral and agro pastoral resources and animal husbandry practices. Results showed that Land use dynamics was characterized by an increase in croplands at an average rate of 46.7 % per year, between 1989 and 2015. On the contrary a decline of pasture lands was observed since 2001 at an average rate of 6.0 % per year. Similar trends in land uses changes were observed by interviewed respondents who depicted an increase in cropping lands (98.5 % of respondents) to the detriment of pasture lands (97.8 % of respondents). To overcome these land use/land cover changes and it subsequent consequences, respondent pastoralists and agro pastoralists have developed local adaptations strategies. Thus, some measures are still needed at government level to sustain local pastoralist and agro-pastoralist efforts and strengthen their adaptive capacity.

Local agro-ecological condition-based food resources to promote infant food security: a case study from Benin

Children are still undernourished in many developing countries. A way to address this issue is to make better use of local food resources. The present study documents local plant and animal resources used for feeding infants and young children across the agro-ecological zones (AEZ) of Benin, with a focus on the availability of resources and consumption forms. It describes similarities and differences among the AEZs and identifies proposals for infant food formulations at the AEZ level. A literature review was performed and supplemented with a survey in 42 villages of eight AEZs of Benin. The selection of municipalities was based on the prevalence of food insecurity. In total 969 people were interviewed through focus group discussions and individual interviews using pre-established interview checklists and questionnaires. Data were processed with statistical tools, including non-metric dimensional scaling analyses, descriptive statistics and Chi2 test of independence. Results showed disparities in the distribution and use of local food resources for infant foods in the AEZs. AEZ 1 represented by Karimama and AEZ 2 represented by Banikoara (both in the Sudanian zone, with about 900 mm rainfall per year in one long rainy season and one long dry season) had the lowest diversity of local food resources used in children’s feeding, while AEZ 5 represented by Aplahoue and Ouesse (both in the Guinean zone, with about 1200 mm rainfall per year over two rainy seasons and two dry seasons), and AEZ 8 represented by Adjohoun and Bopa (both in the Guinean zone with about 1200 mm rain per year) had the highest diversity. The baobab tree (Adansonia digitata) and groundnut (Arachis hypogea) were the plant resources recording the highest number of usages for food in general and infant foods in particular. High similarities in the species used for infant food existed among AEZs 5, 6, 7 and 8 whereas AEZ 1 and AEZ 4 had no match with resources used for infants in the other AEZs, mainly due to food cultures and availability. These findings indicate the usefulness and efficiency of an approach to formulate generic infant food formulas based on grouping AEZs with similar resources. Further studies are needed to assess the quantitative availability of local food resources throughout the year, the links between food prices and purchasing power of the population, and to assess the bioavailability of nutrients in infant foods made from local food resources in relation to food preparation methods.

Remarkable increase in tree density and fuelwood production in the croplands of northern Nigeria

This paper examines trends in woody vegetation and tree species composition in the Sudan zone of West Africa, using the Kano region of northern Nigeria as a case study. The study compares data on tree density, fuelwood production and tree species composition from fieldwork conducted in 1981 and 2016, as well as on several dates of aerial and satellite images since the 1960s. Recent satellite-based reports of greening in arid West Africa as a response to recovery from droughts in the 1970s and 1980s, are examined to explain the observed trends. Tree densities in the goods and services hinterland of Kano city have at least doubled since the drought period, and no decline, rather a slight increase was observed during the drought decades. This contradicts reports of woody vegetation trends from the more arid and less densely populated Sahel zone, which generally observed decline during the drought years and current recovery to pre-drought levels. The remarkable increase in tree numbers in Kano region is accompanied by increasing fuelwood production as suggested by greater concentration by farmers on tree species highly valued for fuel, at the expense of other traditional species. The main driver of such trends is thought to be rapid population growth in the context of a remaining dependence on wood as fuel by both urban and rural populations in Nigeria. Climate is thought to play only a minor role in explaining the trends. These observations confirm trends in fuelwood production observed in Kano region more than three decades previously, and indicate a somewhat Boserupian response to Malthusian-type pressures on available resources. Nevertheless, a return to rainfall levels of the drought decades combined with climate change predictions of increasing temperatures in dryland Africa, may have serious consequences for rural households if energy sources are not diversified.

OBSERVED SHIFT AND MERGE OF HYDROLOGICAL REGIMES IN THE SOTA CATCHMENT, BENIN; AN EVIDENCE OF CLIMATE CHANGE

Sub-Saharan Africa have low resilience capacities to the challenges of climate change. This study is aimed at assessing climate trends and regime shifts at the Sota Catchment, Benin. Long term rainfall and river discharge were analyzed from 1950-2010 in order to generate patterns of changes in the basin. Analysis of the hydro-meteorological were based on the two prominent vegetation zones (Sudan and Guinea Savannah) in the catchment. The rainfall and discharge data were subjected to regime shift analysis and Standardized Precipitation Indices (SPI) were computed. Downward trend of precipitation was observed in the Guinea and Sudan vegetation zones of the catchments from 1970. Rainfall and runoff amount at the two assessed vegetation zones was different in the Guinea and Sudan zone up till 1970. Clear merge of rainfall and runoff amount and patterns was witnessed between the two vegetation zones at 2007. This calls for attention of scientists and policy makers in the region to deploy necessary adaptation measures based on such clear evidence of climate change.

Reference evapotranspiration prediction using hybridized fuzzy model with firefly algorithm: Regional case study in Burkina Faso

Reference Evapotranspiration (ETo) is one of the major components of the hydrological cycle that is very essential in water resources planning, irrigation and drainage management and several other hydrology processes. In irrigation system and design, the prediction of ETo is vital and indispensable for the quantification of crop water needs. This study investigates the capabilities of hybridized fuzzy model with firefly algorithm (ANFIS-FA) for predicting daily reference evapotranspiration over Burkina Faso region. Metrological information at Bobo Dioulasso, Bur Dedougou, and Ouahigouya stations, in Sahelian, Sudano-Sahelian, and Sudanian zone, are used for modelling development. Six different climatic input variable combinations corresponding to 6 models are inspected. The daily Penman-Monteith reference evapotranspiration for the time-period (1998–2012) are used to train and test the models. Several numerical indicators in addition to Taylor diagram are considered to evaluate the performance of the models. Results indicated that the hybrid ANFIS-FA model outperformed the classical ANFIS-based model for all three stations and the model with full inputs climatic data gave the best results. Furthermore, ANFIS-FA is performed the best for Bur Dedougou (Sahalian-Soudanian region) and less at Ouahigouya (sahalian region). In quantitative terms and for instance Bur Dedougou station, ANFIS-FA model increased the prediction accuracy remarkably (SI = 0.043, R2 = 0.97, MAPE = 0.035 and RMSE = 0.24) compared with ANFIS-based model (SI = 0.068, R2 = 0.89, MAPE = 0.037 and RMSE = 0.378). Results revealed the influence of utilizing nature-inspired firefly algorithm to substantially improve performance of the classical ANFIS model optimization for the applied application. Also, the applied modelling strategy can bring a trustful expert intelligent system for predicting reference evapotranspiration at the west desert of Africa.

Impact of human disturbance on bee pollinator communities in savanna and agricultural sites in Burkina Faso, West Africa.

All over the world, pollinators are threatened by land‐use change involving degradation of seminatural habitats or conversion into agricultural land. Such disturbance often leads to lowered pollinator abundance and/or diversity, which might reduce crop yield in adjacent agricultural areas. For West Africa, changes in bee communities across disturbance gradients from savanna to agricultural land are mainly unknown. In this study, we monitored for the impact of human disturbance on bee communities in savanna and crop fields. We chose three savanna areas of varying disturbance intensity (low, medium, and high) in the South Sudanian zone of Burkina Faso, based on land‐use/land cover data via Landsat images, and selected nearby cotton and sesame fields. During 21 months covering two rainy and two dry seasons in 2014 and 2015, we captured bees using pan traps. Spatial and temporal patterns of bee species abundance, richness, evenness and community structure were assessed. In total, 35,469 bee specimens were caught on 12 savanna sites and 22 fields, comprising 97 species of 32 genera. Bee abundance was highest at intermediate disturbance in the rainy season. Species richness and evenness did not differ significantly. Bee communities at medium and highly disturbed savanna sites comprised only subsets of those at low disturbed sites. An across‐habitat spillover of bees (mostly abundant social bee species) from savanna into crop fields was observed during the rainy season when crops are mass‐flowering, whereas most savanna plants are not in bloom. Despite disturbance intensification, our findings suggest that wild bee communities can persist in anthropogenic landscapes and that some species even benefitted disproportionally. West African areas of crop production such as for cotton and sesame may serve as important food resources for bee species in times when resources in the savanna are scarce and receive at the same time considerable pollination service.

Assessment of the changes in the yields of millet crop under different scenarios of climate change using DSSAT model

Agriculture in Mali is vulnerable to climate change. Rainfall remains uncertain for the future, while the increase in temperature is almost a certainty. The objective of this present study was to assess the performance of DSSAT model in simulating the yield of two millet varieties in two agro-ecological zones of Mali under different scenarios of climate change.The performance of two millet varieties in two agro-ecological zones of Mali was assessed using Decision Support System for Agro-Technology Transfer (DSSAT) model under different climate scenarios. Two year experiments were therefore conducted at The Agricultural Research Station of Sotuba located in Sudanian zone and Cinzana in Sahelian zone according to a randomised complete block design with 4 replications. The treatments included Control, Manure 23:10:17 (5000 kg/ha) NPK 15: 15: 15 (50 kg/ha) and NPK+Manure. DSSAT model was used to simulate crop grain yields under two different weather conditions (historical and future). Millet grain yields were higher under the simulations with historical weather data than the simulations with climate change scenarios. Simulation of climate change effects on millet grain yield showed that all scenarios underestimated crop yield compared to the baseline for all treatments and all varieties (CHO, Sanioni, Sosat and IBV8001) All of the varieties showed lowest grain yields under the four treatments for ACCESS1-0 (Hot-Wet) among the scenarios. Based on these findings, it is suggested that, policy should be developed to enhance farmers’ adaptation strategies in the Sudanian and Sahelian zones of MaliKeywords: Agriculture, Rainfall, Temperature, Treatments, Model, Simulation, Grain Yield.

Constraints of seedling survival and recruitment under adult tree of a multi-use species Afzelia africana Sm and Pers in Sudanian region of Benin (West Africa)

Afzelia africana is a tropical multi-use tree species distributed in West, East, and Central Africa. Understanding factors affecting seedlings is crucial to design an effective conservation and restoration plan for the species. Here, we examined the factors constraining seedling density and survival. We randomly established 203 circular plots of 5-m radius around adult trees in two different management systems (Agro-silvo-pastoral system and Protected Area). Then, we focused on the measurement of seedling density, survival/mortality in 2014 and 2015, and estimated disturbance and micro-environment features. We found that seedling mortality rate was higher in Agro-silvo-pastoral system than in Protected area, demonstrating the prominent role of the protected area for the species conservation. The more intense adult trees are pruned, the lower the seedling density beneath, showing a negative effect of pruning on seedling. Seedling density is relatively higher under large trees, revealing the seedlings recruitment bottleneck due to repeated fire and browsing. Furthermore, our data supported the Janzen–Connell effect, suggesting that seedlings are attacked by predators of their parents. Finally, we conclude that management system, pruning intensity, seedling predation determine the regeneration status of A. africana in Sudanian zone. Artificial regeneration program is necessary, as well as shelters and thorny protectors should be established around seedlings under reproductive trees. Firebreaks are also recommended to protect the seedlings and Afzelia stands.

ANTIOXIDANT DEFENSES OF IRRIGATED FORAGE SORGHUM WITH SALINE AQUACULTURE EFFLUENT

ABSTRACT The objective of this work was to evaluate the biomass production and antioxidant enzymatic system activity of irrigated forage sorghum with saline aquaculture effluent under different leaching fractions. The experiment was conducted in the Caatinga Experimental Field of the Embrapa Semiarido, in Petrolina, State of Pernambuco, Brazil. The experimental design was a complete randomized block in a split-plot arrangement with four replications, consisting of three forage sorghum varieties (Volumax, F305 and Sudan) and four leaching fractions (0, 5, 10 and 15%). The vegetal materials were collected when the plants were at the soft-dough stage. The biomass production and activity of the enzymes superoxide dismutase, catalase and ascorbate peroxidase were evaluated. Irrigation with saline aquaculture effluent with leaching fraction of 15% results in low salinity level in the root zone and higher biomass production of forage sorghum Sudan and F305, in semiarid conditions. The antioxidant system was activated in the three sorghum varieties to prevent accumulation of reactive oxygen species, with the synchrony between the enzymes superoxide dismutase and catalase resulting in a better productive response of the varieties Sudan and F305.

Dig Your Own Well: A Political Ecology of Rural Institutions in Western Sub-Saharan Africa

This article examines the influence of changing demographic and human mobility patterns on present-day local institutions and access to basic services in Mali, West Africa. It offers a new political ecological perspective on how local institutions function in rural West Africa and how the spatial character of these institutions shapes service access. The article brings together evidence from archival sources, census data spanning the twentieth century, field surveys, and cartographic data in a novel geospatial analysis of decentralized governance in the western Malian region of Kayes. The article's principal argument is that historically higher population densities in Kayes's semiarid Sahelian zone compared with its subhumid Sudanian zone resulted in higher numbers of officially recognized villages and smaller administrative territories in the former. As population growth took off in the subhumid zone in recent decades, this important institutional difference—codified by law under a succession of governments—has created stark disparities in access to the most fundamental public service: safe drinking water. This article measures these disparities at several geographic scales and explains their causes, which include the permanent settlement of frontier areas where disease vectors had historically kept populations sparse and mobile. These findings reveal the fundamental yet overlooked spatial form and function of rural institutions that have a critical development mandate in one of the poorest regions in the world.