Southwestern Niger Research Articles

Origin and distribution of clay minerals in semi-arid Sahelian soils: case of Kori Ouallam watershed, south-western Niger

Abstract This study examines the origin and distribution of clay minerals of the pedological horizons of Kori Ouallam watershed (south-western Niger). It is based on field sampling campaigns and a series of laboratory analyses. A total of 49 samples were analysed, 28 from surface horizons (0–10 cm depth) and 21 from pedological profiles (0–1 m depth). The samples were analysed by X-ray diffraction on bulk and clay (<2 μm) fractions, X-ray fluorescence spectrometry, laser granulometry, organic matter and calcium carbonate content, macroscopic observations (binocular loupe) and scanning electron microscopy equipped with an energy-dispersive spectrometry system. The pedological horizons are characterized by low organic matter contents (<1%) and no calcium carbonate. The particle-size distribution shows net textural differentiation, with a predominance of sandy loam to sandy clay loam textures in the upper horizons and clay loam to clay in the deep horizons. The main major oxides were SiO2 (46.3–89.0%), Al2O3 (5.0–24.2%) and Fe2O3 (1.0–27.9%). Kaolinite (64–98%) is the predominant clay mineral at all horizons, associated with low to moderate proportions of illite (1–34%) and traces of chlorite. Kaolinite is essentially inherited from the parent rock, whereas illite results from chemical alteration by bisialitization of the primary minerals initially rich in potassium feldspar contained in the parent rock. However, soil texture and organic matter vary independently with clay mineralogy. An extended study of all of the pedological facies that make up south-western Niger, combined with supplementary analyses, would further improve our understanding of clay mineralogy in the Sahelian zone.

Multivariate approach to assess groundwater resources in the multilayer system of Iullemmeden basin in Dosso Region, Southwestern Niger

The Iullemmeden basin groundwater resources were assessed in the Dosso Region for the groundwater management. Classical and multivariate tools of hydrogeochemistry were thus used to stand out main factors impacting the groundwater mineralization. The multilayer system indicates the occurrence of acidic to basic fresh groundwaters but with an excessive content in some places. Good to excellent drinking groundwaters are largely represented in the system. The categorization of groundwater patterns evolves from (i) mixed types namely Ca/Mg-HCO3, Ca/Mg-Cl, Na-Cl/SO4, Ca-Cl/SO4 and Ca/Mg-Cl/SO4 for the Ct3 particularly; (ii) to chloride types such as NaCl, CaCl and MgCl mostly for Ct1 and Ct2; (iii) and the bicarbonate types precisely Na-HCO3, Ca-HCO3, Mg-HCO3 for Ch. The weathering of silicate minerals and dissolution (carbonate and salts) are the major processes in the multilayer system. The increase of EC and salts (halite and gypsum) in Ct2 could come from the relics of ancient seawater during the last regression. In a lesser extent, fertilizers from agricultural and livestock farming also contribute to the mineralization in the study area. The groundwater assessment of the Iullemmeden sedimentary basin in the Dosso Region stands out the main factors and processes characterizing each aquifer of this system, able to useful for a better groundwater resource management.

Exoscopy of Detrital Zircons from Niamey Neoproterozoic Sandstones (Eastern Edge of the West African Craton, Southwestern Niger): Interpretation of Detrital Sediments Provenance

Exoscopy of Detrital Zircons from Niamey Neoproterozoic Sandstones (Eastern Edge of the West African Craton, Southwestern Niger): Interpretation of Detrital Sediments Provenance

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

Characteristics of Gold and Its Mineralization Style in the Boulon Djounga Eastern Perimeter of Liptako Mining Company (Central Southwestern Niger)

Characteristics of Gold and Its Mineralization Style in the Boulon Djounga Eastern Perimeter of Liptako Mining Company (Central Southwestern Niger)

The causal nexus of Trans-Saharan migration: A political ecology approach from Niger

Increased Trans-Saharan migration over the past decade has spurred arguments that climate change or generic conditions of poverty drive West Africans to take this risky journey. These diagnoses are made with little empirical investigation of the conditions facing migrants and their families at home. This article reports on mixed-methods research conducted in southwestern Niger within ten communities where Trans-Saharan migration has recently begun, with interviews conducted at community, household and individual scales. Interviews were conducted within 331 households with or without members involved in Trans-Saharan migration. Individual interviews were also conducted with 67 returned Trans-Saharan migrants and 100 community youth who represent potential Trans-Saharan migrants. We find no evidence that new rainfall fluctuations influence the onset of Trans-Saharan migration. Study communities and migrant families within them are not poorer nor more food insecure than other communities or non-migrant families. The sole difference is that migrant families have more adult men. Interviews with returned Trans-Saharan migrants point to a mix of individual and family motivations for embarking on risky journeys north. A key factor is desperation – driven not by short-term scarcities but by a hopelessness due to life-long experiences of crushing poverty, past periods of recurrent drought, soil impoverishment, and political voicelessness. They go, despite knowing the grave abuses and risks they may face.

The Ornamented Shell of a New Bothremydid Turtle from the Uppermost Cretaceous of Niger

A new pleurodiran turtle is described here. It is identified as attributable to Bothremydidae. The new taxon comes from an upper Maastrichtian (Upper Cretaceous) outcrop located in Southwestern Niger (in the Indamane Mount area, belonging to the Abalak Department of the Tahoua Region). Abalakemys chapmanae gen. et sp. nov. is identified by an almost complete large shell of about 65 cm in length. The new bothremydid turtle is recognized as a member of Bothremydodda, showing several autapomorphies (an exclusive ornamental pattern on the plate’s outer surface, covered by small depressions; small fourth pleural scutes, only anteromedially reaching the sixth pair of costal plates; and noticeably wedged posterior plastral lobe toward the posterior region), as well as a unique combination of characters for this clade. This turtle could belong to Nigeremydini, a poorly understood Maastrichtian to Paleocene lineage of Bothremydodda, which integrates large coastal taxa that inhabited the African Trans-Saharan seaway, and for which shell information is currently extremely limited.

Evaluation of the Impact of Seasonal Agroclimatic Information Used for Early Warning and Farmer Communities’ Vulnerability Reduction in Southwestern Niger

In Niger (a fully Sahelian country), the use of climate information is one of the early warning strategies (EWSs) for reducing socio-economic vulnerabilities in farmer communities. It helps farmers to better anticipate risks and choose timely alternative options that can allow them to generate more profit. This study assesses the impacts of the use of climate information and services that benefit end-users. Individual surveys and focus groups were conducted with a sample of 368 people in eight communes in Southwestern Niger. The survey was conducted within the framework of the ANADIA project implemented by the National Meteorological Direction (NMD) of Niger. The survey aims to identify different types of climate services received by communities and evaluates the major benefits gained from their use. Mostly, the communities received climate (73.6%) and weather (99%) information on rainfall, temperature, dust, wind, clouds, and air humidity. Few producers in the area (10%) received information on seasonal forecasts of the agrometeorological characteristics of the rainy season. The information is not widely disseminated in the villages during the roving seminars conducted by the NMD. For most people, this information is highly relevant to their needs because of its practical advice for options to be deployed to mitigate disasters for agriculture, livestock, health, water resources, and food security. In those communities, 82% of farmers have (at least once) changed their routine practices as a result of the advice and awareness received according to the climate information. The information received enables farmers (64.4%) to adjust their investments according to the profile of the upcoming rainfall season. The use of climate information and related advice led to an increase of about 64 bunches (equivalent to 10 bags of 100 kg) in annual millet production, representing an income increase of about 73,000 FCFA from an average farmland of 3 ha per farmer. In addition, the use of climate information helps to reduce the risks of floods and droughts, which often cause massive losses to crop production, animal and human life, infrastructure, materials, and goods. It has also enabled communities to effectively manage seeds and animal foods and to plan social events, departures and returns to rural exodus. These analyses confirm that the use of climate information serves as an EWS that contributes to increasing the resilience of local populations in the Sahel.

Arsenic and other trace elements in groundwaters and surface waters in the gold mining region of the Nigerien Liptako (Southwestern Niger)

Arsenic and other trace elements in groundwaters and surface waters in the gold mining region of the Nigerien Liptako (Southwestern Niger)

Suffering for dignity and hope: young Nigeriens choose perilous trans-Saharan migration

ABSTRACT Hopelessness and indignity are not captured by standard measures of poverty. This study of the perilous trans-Saharan labor migration from southwestern Niger provides a deeper understanding of the experiences that drive young men to take this significant risk – to their mental and physical health. Within the 10 communities where trans-Saharan migration began, 331 household interviews, 66 returned immigrant interviews and 100 interviews of youth were conducted to understand the motivations of migrants and the material conditions faced at home. The research illuminates the deeply human motivations that drive these decisions including desires for greater autonomy, equitable politics, and productive work.

Effects of restoration of degraded lands on soils physicochemical properties and adaptability of planted woody species in southwestern Niger

AbstractThis study examines the effects of restoration of degraded lands on soils physicochemical properties and adaptability of planted woody species over a period of 4–6 years. It is based on: (1) Physicochemical analyses of soils (granulometry, calcimetry, and organic matter); (2) measures carried out for the dimensioning of anti‐erosion structures; (3) dendrometric measurements on planted woody species on a density from 96 to 625 plants/ha, and the excavations of their root systems. The soils are characterized by low levels of organic matter (<1%), and no calcium carbonate. Soil tillage through deep sub‐soiling resulted in an improvement in soils quality marked by average proportions of clay (28.3%), silt (27.3%) on the anti‐erosion structures, whereas the control sites are dominated by sand particles (64%) on average. The degradation mechanism of anti‐erosion structures is mainly controlled by natural factors including topography, rainfall, and sand content of the soils with strong positive correlations (; ; respectively). Restoration activities have led to the reconstitution of vegetation cover on degraded soils. Eucalyptus camaldulensis groups showed better adaptation as evidenced by their high structural shape parametres including Lorey's mean height (5.16–8.03 m), and mean crown diameter (1.66–3.3 m) with a tracer‐type root system and high root density (74–88 roots) observed at 30 cm from the main stem. This study provides substantial information on the contribution of erosion control measures and their interactions with soil and vegetation resources. It constitutes a scientific tool that is well‐adapted to the Sahelian (Niger, Mali, Burkina Faso, Chad, Mauritania and Senegal) context indispensable for the implementation of sustainable development strategies. The results thus obtained can be used as a reference for the choice of woody species to be planted according to the toposequence and the nature of the anti‐erosion structures made, with a good control of their durability while taking into account the productivity of the soils.

Economic importance of fuelwod in family resources is not a sufficient trigger factor for farmers to restore their parklands in south-western Niger

Economic importance of fuelwod in family resources is not a sufficient trigger factor for farmers to restore their parklands in south-western Niger

Iklan Aesthetics in Niger: Identity and Adornment from Servility to Self-agency

<i>Iklan</i> Aesthetics in Niger: Identity and Adornment from Servility to Self-agency

Study of Cyanide Contamination of Market Garden and Agricultural Products Grown Around the Samira Gold Mine (Niger)

The term cyanide refers to all the compounds producing the ─C≡N group. It comes from both anthropogenic and natural origins. Its presence in the environment is largely related to gold mining. Cyanide is very scary because of its toxicity causing very deadly environmental consequences. The objective of this work is to study the fate of cyanide and assess its contamination on the environment in the vicinity of a potential source of pollution such as a gold mine. In this study, soils and foods samples from the Samira gold mine and its surroundings in southwestern Niger were collected, analysed and compared with equivalent control samples grown in areas free of any industrial cyanide source. Total cyanide contents in the soils of the Samira site and its surroundings are 2 to 104 times higher than the Canadian standard (0.90 µg g^-1 CN^-) for agricultural soils, while the control soils are almost free of cyanide. These results show a migration of cyanide from the mine tailings to the surrounding area and these soils are unsuitable for any crop. The produced foods on these polluted soils have total cyanide contents 2 to 5 times higher than their controls. These contaminated matrices reveal negative impacts of the Samira mine's gold activities on its immediate environment. Ingestion of these foods would lead to serious health consequences for local populations.

Dynamics and Vulnerability of Hydrogeomorphological Units to the Degradation of Climatic Conditions in the Watershed of the Birnin Lokoyo Pond (Iullemmeden Basin, Southwestern Niger)

The present study concerns the lowlands of the Birnin Lokoyo watershed located in the Matankari Rural Commune (Southwestern borders of the large Iullemmeden basin in the Niger). Dominated by the Birnin Lokoyo pond, this watershed faced with the continuous silting up of the minor bed, dissipates further upstream in the east, so that it moves downstream to the west for the benefit of the populations of Matankari city. The main objective of this work is to analyze the representative elements of the new climatic and environmental situation as well as the various factors determining the surface conditions in the watershed. The methodological approach is based on documentary research, field observations, individual surveys and interviews with targeted groups. The results show that the silting up of the lowlands is the result of the concomitant degradation of the plant cover and the soils, which, as a result, triggered the development of crusting surfaces and area erosion on the slopes. The study underlined the importance of endogenous knowledge in the choice of remedies against the silting up of lowlands. In addition, rational land management practices on plateaus and structures (within the watershed) do not seem to be in phase with topographical factors and the tectonic framework. This work is part of the vision of better management of glacis on the banks, but also of sills subject to regressive erosion upstream and in order to guide the policies of resilience of the populations.

Wind erosion response to past and future agro-pastoral trajectories in the Sahel (Niger)

ContextWind erosion plays a major role in land degradation in semi-arid areas, especially in the Sahel. There, wind erosion is as sensitive to land use and land management as to climate factors. Future land use intensification may increase wind erosion and induce regional land degradation.ObjectiveWe aimed to estimate wind erosion responses to changing land management in a Sahelian region.MethodsWe defined land use intensification scenarios for a study site in southwestern Niger for two historical situations (1950s and 1990s), and two alternative prospective scenarios (2030s: extensive or intensive). We simulated vegetation growth and horizontal sediment flux of wind erosion for the corresponding landscapes.ResultsAnnual amounts of horizontal sediment flux increased with land management changes from 1950s (nil flux) to 1990s (176 kg m−1 yr−1) and 2030s (452 to 520 kg m−1 yr−1), mostly because of differences in land use, declining soil fertility, and practices decreasing the dry vegetation. For 2030s, intensive scenario exhibited larger vegetation yields than extensive conditions, but similar large values of horizontal sediment flux, thus questioning the sustainability of both scenarios. Realistic sets of practices had as large an influence as the largest theoretical range of practices on the variability of annual horizontal sediment flux. This variability was as large as that due to meteorological conditions.ConclusionsThis study demonstrates that the environmental impact of land use and management practices, of which wind erosion is an aspect, must be assessed at the landscape scale to account for the variability in land cover and associated land management.

Assessment of Oil Spillage Impact on Vegetation in South-Western Niger Delta, Nigeria

The present study assesses the impact of oil spillage in the Southwestern Niger Delta of Nigeria over the past fifty (50) years. It further sought to find out the driving forces and implications of oil spillage on vegetation, livelihoods and other key parameters. The study employed geospatial techniques and a secondary source of data to achieve the objectives set out in this study. The Global Moran I statistical tool was used to determine the spatial autocorrelation based on feature locations and attribute values. We observed built-up areas, bare land, and less dense vegetation had an overall increment of 1975.98 km2, 1370 km2 and 23805 km2, respectively. Dense vegetation had declension of 22058.33 km2 over the past five decades. Findings depict a declining trend in Normalized Difference Vegetation Index, attributed to oil spillage as the key contributory factor. Occasioned by anthropogenic activities, the driving forces were traced to attacks on oil pipelines during conflicts and illegal means of creating leakages to siphon crude oil for sale. To achieve sustainability in oil spill management in the Delta, the study recommends further research to ascertain the cost of losses incurred apply geospatial techniques to monitor and predict environmental changes that inform decisions of key actors.

Late Miocene\u2013Early Pliocene planktic foraminiferal biostratigraphy of deep offshore southwestern Niger Delta

The planktic foraminiferal biostratigraphy of the deep offshore southwestern Niger Delta has been studied from three wells (DPW-1, DPW-2 and DPW-3). A total of 418 ditch cutting samples (104 samples from DPW-1, 165 from DPW-2 and 149 from DPW-3) taken at 18-m intervals were subjected to standard micropaleontological processing techniques. In total, 42, 52 and 40 planktic foraminiferal species were identified from DPW-1, DPW-2 and DPW-3, respectively. The identified planktic species allow the delineation of the studied section into four biozones—Globorotalia acostaensis (N16), Globigerinoides obliquus extremus/Globorotalia merotumida (N17), Globorotalia margaritae primitiva (N18) and Globorotalia margaritae evoluta/Globigerina nepenthes (N19) zones, based on the first appearance datums (FADs), last appearance datums (LADs) of the nominate taxa and associated assemblages. The well sections dated Late Miocene to Early Pliocene based on the occurrence of certain diagnostic planktic foraminiferal datums such as FADs Globorotalia acostaensis, Globigerinoides obliquus extremus, Globorotalia merotumida/plesiotumida, Globorotalia margaritae primitiva and the LADs Globigerina nepenthes, Globorotalia margaritae primitiva and Globorotalia margaritae evoluta. The Miocene/Pliocene boundary was placed at the FAD Globorotalia margaritae primitiva. In the Niger Delta, this boundary is commonly placed at the FADs Globorotalia margaritae margaritae and Globorotalia crassaformis probably due to nonrecovery of Globorotalia margaritae primitiva. However, in this studied section of the deep offshore southwestern Niger Delta, FAD Globorotalia margaritae primitiva occurs consistently in the three study wells and is therefore considered an appropriate datum for the placement of the Miocene/Pliocene boundary.

Faidherbia albida (Delile) Tree Dieback Effects on Crop Production in the Parkland Agroforests of Southwestern Niger

Faidherbiaalbida is an agroforestry tree species playing important agroecological and socioeconomic roles in arid and semiarid zones in Africa. For many years, anthropogenic and abiotic stresses were considered as the main threats for the species in West African parkland agroforests. Considerable dieback has recently occurred in F. albida trees of parkland agroforests in central southwestern Niger, and the causes are unknown. The objectives of this study are to (i) investigate the magnitude of dieback of F. albida trees and (ii) assess local community perceptions of the effects of F. albida dieback on crop production. The health status and phenology of 213 F. albida trees were observed in the area where the dieback is occurring. Similarly, a sample of 144 people, 86% of which were farmers, was surveyed. Dieback incidence of F. albida trees was 19%, with mortality of 6%. Large-diameter trees had greater dieback than small-diameter trees. The most affected parts of the tree were the branches at 54% and the trunks at 39%. The populations noted a 33–55% reduction in the yields of major crops. This dieback of F. albida trees poses a serious threat to the survival of rural communities. Further studies can be conducted to identify the cause or cause of the dieback to guide the suitable agroforestry parkland management strategies.

Multi-Criteria Analysis Using Remote Sensing and GIS: Insight into Groundwater Potential of the Fissured Aquifers in the Liptako Socle (Southwestern Niger)

In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve the region’s water coverage. The cartographic approach developed made it possible to establish synthetic maps based on multi-criteria analysis. The hydrogeological parameters selected include fracturing data, drainage system, slope and piezometric level as well as shallow and deep lithology. The choice of these criteria is based on their physical meaning but also on the availability of data. The integration of all the criteria in a GIS allowed to generate maps of recharge and potential productivity of fractured aquifers in the area. The validation of these thematic maps with independent data confirms their utility as reference standards for accessibility for future resource exploitation. Like any spatialization tool, potential recharge maps will provide valuable information about areas where infiltration is more important, and help control and manage risk zoning. The upward evacuation effect is even more prominent along the lineaments, faults or fractures: thus, to avoid possible pollution and to locate the future hydraulic structures, the analysis of the potential recharge zones remains necessary. The potential productivity index map, in addition to the very punctual sites identified by the fracturing study, made it possible to define areas of high potential productivity.