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Focusing on an area of the savannah in northern Ghana and southwestern Burkina Faso, Land, Mobility, and Belonging in West Africa explores how rural populations have secured, contested, and negotiated access to land and how they have organized their communities despite being constantly on the move as farmers or migrant laborers. Carola Lentz seeks to understand how those who claim native status hold sway over others who are perceived to have come later. As conflicts over land, agriculture, and labor have multiplied in Africa, Lentz shows how politics and power play decisive roles in determining access to scarce resources and in changing notions of who belongs and who is a stranger.

PurposeIn the mesic savannas of West Africa, areas around villages of relatively tall and dense forest vegetation are often found. These ‘forest islands’ are presumably the direct outcome of human activity. To better understand these patches with relatively luxuriant vegetation, our study focused on how they influence soil aggregate stability- a key indicator of soil resilience to degradation through erosion. We compared the proportion of stable soil aggregates of the forest islands with nearby croplands and natural savanna vegetation across a precipitation transect in West Africa for which mean annual precipitation at the study sites ranges from 0.80 to 1.27 m a−1.MethodsSoil samples were taken from 0–5 cm and 5–10 cm depths and stability of soil aggregate groups with diameters: > 500 μm, 500–250 μm and 250–53 μm (viz. “macroaggregates”, “mesoaggregates” and “microaggregates” respectively) determined using the wet sieving method.ResultsThe results showed significantly (p < 0.05) higher proportion of stable soil meso- and macro-aggregates in forest islands and natural savanna than in agricultural soils. Although there was no effect of land-use type on microaggregate stability, there was a strong tendency for the stable microaggregates across all land use types to increase with increasing precipitation. Soil organic carbon and iron oxides contents were the most important factors influencing meso and macro-aggregate stability in the West African ecosystems.ConclusionWe conclude that formation of stable soil microaggregates in the West African ecosystems was climate or precipitation driven whereas the more labile and larger-size groups of meso-and macro- aggregates was land-use driven. The study provides first insights in soil quality processes in a poorly studied but unique phenomenon of man-made forest islands in West Africa.

Focusing on an area of the savannah in northern Ghana and southwestern Burkina Faso, Land, Mobility, and Belonging in West Africa explores how rural populations have secured, contested, and negotiated access to land and how they have organized their communities despite being constantly on the move as farmers or migrant laborers. Carola Lentz seeks to understand how those who claim native status hold sway over others who are perceived to have come later. As conflicts over land, agriculture, and labor have multiplied in Africa, Lentz shows how politics and power play decisive roles in determi

According to estimates by the International Land Coalition based at the International Fund for Agricultural Development (IFAD), 57 million hectares of land have been leased to foreign investors since 2007. Current research has focused on human rights issues related to inward investment in land but has been ignorant of water resource issues and the challenges of managing scarce water. This handbook will be the first to address inward investment in land and its impact on water resources in Africa. The geographical scope of this book will be the African continent, where land has attracted the attention of risk-taking investors because much land is under-utilised marginalized land, with associated water resources and rapidly growing domestic food markets. The successful implementation of investment strategies in African agriculture could determine the future of more than one billion people. An important factor to note is that Sub-Saharan Africa will, of all the continents, be hit hardest by climate change, population growth and food insecurity. Sensible investment in agriculture is therefore needed, however, at what costs and at whose expense? The book will also address the livelihoods theme and provide a holistic analysis of land and water grabbing in Sub-Saharan Africa. Four other themes will addressed: politics, economics, environment and the history of land investments in Sub-Saharan Africa. The editors have involved a highly diverse group of around 25 expert researchers, who will review the pro and anti-investment arguments, geopolitics, the role of capitalist investors, the environmental contexts and the political implications of, and reasons for, leasing millions of hectares in Sub-Saharan Africa. To date, there has been no attempt to review land investments through a suite of different lenses, thus this handbook will differ significantly from existing research and publication. The editors

Urban expansion is an increasing threat to biodiversity, especially in tropical Africa where biodiversity hot spots are being encroached upon by fast‐growing cities. Threatened species include bees and other pollinators, which deliver important ecosystem services but are sensitive to land use changes. We investigated the impact of urbanisation and vegetation management practices on pollinator abundance, bee diversity, and bee functional traits. We sampled 126 locations in a stratified random design across an urbanisation gradient in two medium‐sized cities in the West African Forests biodiversity hot spot, encompassing three management practices (farmed sites; amenity lands, i.e. green spaces managed for aesthetics; informal green spaces), and tested their effect with generalised linear models. Urbanisation did not affect bee abundances or diversity but had a negative impact on both wasp and beetle abundances. There was also a management‐mediated impact of urbanisation on bee abundances, which decreased with urbanisation on farmed sites but not amenity land or informal green spaces. Management practices alone influenced bee abundances with farms harbouring fewer bees, and amenity lands fewer beetles. Bee genera occurrence and dominance patterns were influenced by both urbanisation and management, with some otherwise common genera rare in urban areas. Most functional traits were influenced by management, with fewer polylectic bees, cavity‐nesting bees and long‐tongued bees in farmed sites. Amenity lands hosted smaller bees and fewer savanna specialists. Some traits were influenced by urbanisation, with more long‐tongued bees and cavity‐nesting bees found in urban areas. Synthesis and applications. Pollinator responses to urbanisation are complex. In our research, we demonstrate how bee, lepidopteran, and non‐fruit fly abundances have been maintained across an urbanisation gradient in tropical Africa, but not wasp and beetle abundances. Moreover, bee community composition and the distribution of traits shifted markedly. How green spaces were managed was also critical. We found that farmed sites hosted the lowest bee abundances and amenity lands the fewest beetles. Retaining informal green spaces and amenity lands in African cities, including protecting nesting sites for stingless bees, and limiting pesticide application would be important for conserving bees and the pollination service they provide to both crops and native vegetation. Foreign Language Résumé L'expansion urbaine est une menace importante pour la biodiversité, particulièrement en Afrique où les hotspots de biodiversité sont rapidement mités par les villes. Les pollinisateurs, qui fournissent des services écosystémiques importants, sont menacés du fait de leur sensibilité aux changements d'utilisation du territoire. Nous avons étudié l'impact de l'urbanisation et de trois types de gestion des espaces verts (aires agricoles, lieux d'agréments, espaces verts informels) sur l'abondance des pollinisateurs et sur la diversité et les caractères fonctionnels des abeilles. Nous avons échantillonné 120 emplacements de manière aléatoire stratifiée dans les trois types d'espaces verts le long d'un gradient d'urbanisation dans deux villes du hotspot de biodiversité des forêts guinéennes de l'Afrique de l'Ouest, et testé leurs effets avec des modèles linéaires généralisés. L'urbanisation n'affecta ni l'abondance ni la diversité des abeilles, mais diminua l'abondance des guêpes et des coléoptères. Couplée à la gestion, elle affecta également l'abondance des abeilles, qui diminua uniquement dans les aires agricoles. La gestion eu par ailleurs un effet, les aires agricoles abritant moins d'abeilles et les lieux d'agréments moins de coléoptères. Le schéma d'occurrence et de dominance des différents genres d'abeilles fut influencé par l'urbanisation et la gestion, avec certains genres, autrement communs, étant rares en zones urbaines. La gestion influença la plupart des caractères fonctionnels, avec moins d'abeilles polylectiques, d'abeille cavicoles et d'abeilles à langue longue dans les aires agricoles. Les lieux d'agréments abritaient des abeilles plus petites et moins de spécialistes des savanes. La proportion d'abeilles à langue longue et d'abeilles cavicoles augmenta avec l'urbanisation. Synthèse et application. Les réactions des pollinisateurs face à l'urbanisation sont complexes. Nous démontrons que l'abondance des abeilles, papillons et mouches est maintenue le long d'un gradient d'urbanisation en Afrique tropicale, mais pas celle des guêpes ni des coléoptères. De plus, la composition communautaire des abeilles et la distribution de leurs caractères fonctionnels sont clairement modifiées. La gestion des espaces verts est également cruciale: les aires agricoles abritent moins d'abeilles, les lieux d'agréments moins de coléoptères. Conserver des espaces verts informels et des lieux d'agréments dans les villes africaines, protéger les sites de nidification, et limiter l'application de pesticides sont nécessaires pour conserver les abeilles et la pollinisation qu'elles fournissent aux cultures et à la végétation indigène. Pollinator responses to urbanisation are complex. In our research, we demonstrate how bee, lepidopteran, and non‐fruit fly abundances have been maintained across an urbanisation gradient in tropical Africa, but not wasp and beetle abundances. Moreover, bee community composition and the distribution of traits shifted markedly. How green spaces were managed was also critical. We found that farmed sites hosted the lowest bee abundances and amenity lands the fewest beetles. Retaining informal green spaces and amenity lands in African cities, including protecting nesting sites for stingless bees, and limiting pesticide application would be important for conserving bees and the pollination service they provide to both crops and native vegetation.

About 3000 years ago, a major vegetation change occurred in Central Africa, when rainforest trees were abruptly replaced by savannas. Up to this point, the consensus of the scientific community has been that the forest disturbance was caused by climate change. We show here. that chemical weathering in Central Africa, reconstructed from geochemical analyses of a marine sediment core, intensified abruptly at the same period, departing substantially from the long-term weathering fluctuations related to the Late Quaternary climate. Evidence that this weathering event was also contemporaneous with the migration of Bantu-speaking farmers across Central Africa suggests that human land-use intensification at that time had already made a major impact on the rainforest.

We analysed in the work how change in land use/land cover influences on flood characteristics (frequency and magnitude) using a model inter-comparison approach, statistical methods and two land use scenarios (land use scenario A and land use scenario B) for three time horizons. The derived land use maps from these scenarios were considered as forcing inputs to two physically based hydrological models (SWAT and WaSiM). The generalized Pareto distribution combined with the Poisson distribution was used to compute flood frequency and magnitude. Under land use scenario A, croplands increase at the annual rate of 0.7% while under land use scenario B, it increases by 1.13% between 2003 and 2029. The expansion of croplands indubitably enhances flood risks. Although there was a general agreement about the sense of the variation, the magnitude of change in flood characteristics was highly influenced by the model type. The rate of increase in flood quantiles simulated from SWAT (0.36–1.3% for 10-year flood) was smaller than the corresponding magnitude of changes simulated from WaSiM (2.6–7.0% for 10-year flood) whatever the scenarios. The expansion of agricultural and pasture lands at the yearly rate of 0.7% under land use scenario A (respectively, 1.13% under land use scenario B) leads to an increase of 3.6% (respectively, 5.4%) in 10-year flood by considering WaSiM. This study is among the first of its kind to establish a strong statistical relation between flood severity/frequency and agricultural land expansion and natural vegetation reduction. The results of this study are relevant and useful to the scientific research community as well as the decision makers for framing appropriate policy decisions towards the management of extreme events and the land use planning/management in future in the region.

Climate change is adversely affecting the burden of infectious disease throughout the world, which is a health security threat. Climate-sensitive infectious disease includes vector-borne diseases such as malaria, whose transmission potential is expected to increase because of enhanced climatic suitability for the mosquito vector in Asia, sub-Saharan Africa, and South America. Climatic suitability for the mosquitoes that can carry dengue, Zika, and chikungunya is also likely to increase, facilitating further increases in the geographic range and longer transmission seasons, and raising concern for expansion of these diseases into temperate zones, particularly under higher greenhouse gas emission scenarios. Early spring temperatures in 2018 seem to have contributed to the early onset and extensive West Nile virus outbreak in Europe, a pathogen expected to expand further beyond its current distribution, due to a warming climate. As for tick-borne diseases, climate change is projected to continue to contribute to the spread of Lyme disease and tick-borne encephalitis, particularly in North America and Europe. Schistosomiasis is a water-borne disease and public health concern in Africa, Latin America, the Middle East, and Southeast Asia; climate change is anticipated to change its distribution, with both expansions and contractions expected. Other water-borne diseases that cause diarrheal diseases have declined significantly over the last decades owing to socioeconomic development and public health measures but changes in climate can reverse some of these positive developments. Weather and climate events, population movement, land use changes, urbanization, global trade, and other drivers can catalyze a succession of secondary events that can lead to a range of health impacts, including infectious disease outbreaks. These cascading risk pathways of causally connected events can result in large-scale outbreaks and affect society at large. We review climatic and other cascading drivers of infectious disease with projections under different climate change scenarios.5E6fdnCC7GZ6vtJap2g1wpSupplementary file1 (MP4 328467 KB)