Working the Sahel (Global Environmental Change Series)

This ebook seems at how humans within the semi-arid stipulations of the Sahel do something about their harsh surroundings. It attracts on 4.
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Global Environmental Change Series Hardcover: Routledge August 3, Language: Related Video Shorts 0 Upload your video. Share your thoughts with other customers. Write a customer review. There was a problem filtering reviews right now. Please try again later. Mortimore, a British geographer with 28 years of residence in northern Nigeria and several books to his name, is an adept and rigorous practitioner of local-level cultural ecology.

Bill Adams began his career examining the fate of Northern Nigeria's large irrigation schemes, and has since written extensively on conservation and sustainability questions. Working the Sahel emerged from a five year British-funded investigation into patterns of agricultural intensification and labor use in four sub-locations located on a transect of varying population density between Kano and the Nigeria-Niger border.

This book subsumes some of Mortimore's long term datasets and archival material, permitting longitudinal evaluations. Working the Sahel is a tightly focused research monograph. The key question it poses is how individual skills are exercised in "strategic and tactical" ways by households in Northern Nigeria, and how resource endowments are managed under varying population densities.

The starting point is that constraints on farming activities can be distilled into four categories; rainfall, bioproductivity of plants and soil, labor, and the availability of capital. Labor constraints in Nigeria and elsewhere have been generally been relaxed as population densities rise, permitting some combination of intensification of agricultural production in-situ, economic diversification out of agriculture, and circular migration.

Adaptation - a term much critiqued by anthropologists - is used quite sensibly here to describe the reflexive, longer term restructuring of Sahelian rural systems in the response to these four constraints. Both flexibility and adaptability are demanded of Sahelian farmers. The core of the book concerns the day to day management of labor.

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In the four villages, high frequency time-budget observations by local researchers took place over four years, initially with the men, women and children of around 45 households. The study found that some labor inefficiencies are inevitable in dryland farming systems. Short cropping seasons in the drier villages concentrate labor demand; but since crop growth is dependent on rainfall, drought years can actually provoke labor surpluses.

To maintain flexibility, therefore, labor is matched to resource endowments, and by switching between livelihood activities. Women and children make significant contributions to agricultural labor, that are greater in the drier and more extensive farming systems where Islamic seclusion is more relaxed. A picture emerges of biodiversity maintained by cultivation practices, and only localized episodes of degradation, largely driven by precipitation fluctuations.

In their view, "Nothing could be further from the scenario of reckless resource degradation which has been put about by some academics and development agencies" p The book also argues farmers have already developed pathways to "indigenous intensification" p97 in the drylands, where denied access to fertilizer. Adaptive responses in the four villages include significant non-farm activities, since as Mortimore and Adams are at pains to stress, risk is spread through diversification.

Impelled by economic factors, such as the instabilities generated by Nigeria's commodity booms and busts, and the recognition that animals offer investment opportunities, a pattern has emerged of "the more crops produced, the more livestock kept" p , in mixed farming systems. Private accumulation through petty trading in rural periodic markets is just part of a widely developed trading system, and markets also provide a wide range of social functions. Long distance migration, described much too briefly in the book, articulates with broader economic opportunity in regional hinterlands, and nationally.

The authors personalize some of these labor tradeoffs and decision-making processes by profiling six farmers, by means of activity charts and brief personal histories. These profiles highlight how and when households deploy their labor. The book concludes by stressing that agricultural development initiatives in the Sahel fail when they are reductionist, and ignore diversity and variability.

There is a dig here at farming systems research, which has underpinned agronomic development programs in the Sahel, for its focus on efficiency criteria. Dryland farmers are not profit or efficiency maximizers, since ".. In particular for the West African Sahel, livestock constitutes the first renewable resource and is mainly characterized by an extensive use of pastures in rangelands. Since the Centre de Suivi Ecologique CSE operationally estimates the total annual biomass in Senegal in order to monitor the fodder availability of the national pastoral rangelands.

Field data is collected along 1 km transects at 24 sites at the end of the wet season. Here, herbaceous and woody leaf biomass is measured and summed to the total available fodder biomass. This is done each year since Using a linear regression with satellite images, the field data is projected to whole Senegal and gives stakeholders an estimation on the quantity and distribution of fodder biomass.

Between and , this method was implemented using the seasonal integrated NDVI i. In this context, we developed a new operational system for monitoring total fodder biomass, including both herbaceous and woody leaf biomass.

Working the Sahel (Global Environmental Change Series) - download pdf or read online

In the future, such early warning models should enable stakeholders to take decisions as early as September current year as biomass shortage with regard to livestock by triggering protocols designed for livestock management e. Land degradation mechanisms are related to two main categories, one related to climate change and one associated with local human impact, mostly land use change such as expansion of cultivation, agricultural intensification, overgrazing and overuse of woody vegetation.

Land degradation characteristics, triggers and human influence are manifold and int errelated. Some of the indicators can be monitored using Earth Observation techniques underlined in red: During the last four decades, the Sahel was affected by below-normal precipitation with two severe drought periods in —73 and in — These negative perceptions have been opposed with recent findings of improved greenness mostly in relation to recent improvement in rainfall.

The assessment of land degradation and quantifying its effects on land productivity have been both a scientific and political challenge. After four decades of Earth Observation applications, little agreement has been gained on the magnitude and direction of land degradation in the Sahel.

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The number of Earth Observation datasets and methods, biophysical and social drivers and the complexity of interactions make it difficult to apply aggregated Earth Observation indices for these non-linear processes. Hence, while many studies stress that the Sahel is greening, others indicate no trend or browning.

While there is a clearly positive trend in biomass production at Sahel scale, a loss in biodiversity and locally encroaching barren land are observed at the same time. Multi-scale Earth Observation analyses show that neither the desertification nor the greening paradigms can be generalized, as both attempt to simplify a very complex reality.

Heterogeneity is an issue of scale, and very coarse-scaled vegetation trend analyses reveal a greening Sahel. However, locally-scaled studies are not uniform, observing greening and degradation at the same time. We suggest several improvements: Furthermore, we underline the relevance of field data and experience, and results achieved by remote sensing techniques should not be interpreted without contextual knowledge.

Download the full article here: This is the abstract of the successful application: Human and climate induced desertification has been a major issue for livelihoods and food security in drylands. In this context, the Sahel has been subject to various controversial studies. Earth Observation EO studies show a positive trend in vegetation greenness over the last decades, which has been interpreted as an increase in biomass and contradicts prevailing narratives of widespread degradation.

However, new scientific outcome suggests a massive loss in biodiversity, which again contradicts the beneficial effects of the greening theory. These apparent oppositions result from little investment that has been made in studying long-term ground data.

An Introduction to the ARCC Adaptation in the Sahel Series | Global Climate Change

Thus, the overall purpose of this project is to assess the opposing trends of biomass increase and species decline in the Sahel. By combining a range of long-term in-situ field data records s-today with EO time series and Very High Resolution VHR satellite imagery, an improved understanding on the role of trees, herbs and species on the greening Sahel will be achieved. T rends will be translated in ecosystem services and beneficial effects on livelihoods. Furthermore, the scientific understanding of linkages between ground and satellite data and their applicability across scales will be improved.

New monitoring methods of biophysical variables address challenges in land management and food security. Finally, this project will encourage a North-South collaboration in common scientific interest that is relevant for development and environmental research. Making use of 27 years of ground measurements, we were able to find evidence of the role of trees and grass on the greening of the Senegalese Sahel.

Moreover, woody species abundance data provided by Gray Tappan from shows changes in biodiversity over 30 years.

We thus provide ground based evidences against the conventional view of irreversible degradation in the Sahel. After a dry period with prolonged droughts in the s and s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness over the last decades which is known as the re-greening of the Sahel.

However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings.

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Thus, deductions on a possible increment in biomass remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series — of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass of woody species, herb biomass, and woody species abundance in different ecosystems located in the Sahel zone of Senegal. This increase in woody biomass did not reflect on biodiversity with 11 of 16 woody species declining in abundance over the period.

We conclude that the observed greening in the Senegalese Sahel is primarily related to an increasing tree cover that caused satellite-driven vegetation indices to increase with rainfall reversal. Fensholt Ground and satellite based evidence of the biophysical mechanisms behind the greening Sahel.


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Another very interesting publication using object based methods to detect single trees on very high resolution imagery is online. It can be downloaded for free until late October using this link: In the past 50 years, the Sahel has experienced significant tree- and land cover changes accelerated by human expansion and prolonged droughts during the s and s. This study uses remote sensing techniques, supplemented by ground-truth data to compare pre-drought woody vegetation and land cover with the situation in High resolution panchromatic Corona imagery of and multi-spectral RapidEye imagery of form the basis of this regional scaled study, which is focused on the Dogon Plateau and the Seno Plain in the Sahel zone of Mali.

Object-based feature extraction and classifications are used to analyze the datasets and map land cover and woody vegetation changes over 44 years. Interviews add information about changes in species compositions. Species decline and encroachment of degraded land are observed. However, the direction of change is not always negative and a variety of spatial variations are shown. Although the impact of climate is obvious, we demonstrate that anthropogenic activities have been the main drivers of change. It was released by the University of Bayreuth http: New research works show: Not global climate change alone, but rather foremost the local actions of people impact the face of their environment.

Or is green vegetation now spreading into regions that were once barren deserts? The West African section of the Sahel zone located at the southernmost edge of the Sahara, which extends from the Atlantic to the Red Sea, has been the source of reason for a wide variety of prognoses over the recent years. Extreme periods of drought during the s and s were considered as indices of growing desert regions across the globe.

However, over the last two decades a rise in precipitation has been observed across the West African Sahel. With this controversy as the backdrop, an international research team led by geographer Martin Brandt of the University of Bayreuth examined the vegetation development in the West African Sahel more closely.

High and coarse resolution satellite data as well as wide range of measurement results from the last decades enabled conclusions to be drawn on climate and vegetation trends and field research brought regional and local particularities to light. Here some determinations were made: There is no uniform development in the West African Sahel. Not only the climate but also especially various forms of land-use — farming, forestry management or village development — are mostly responsible for the way the landscape there appears, and which resources it offers the people.

Regional differences due to land and forest management — case studies in Mali and in the Senegal. This development is especially pronounced in the Senegal and in western Mali. Here there are clear regional differences with respect to plants that have multiplied over time: Not only does one observe the wild growth of trees, bushes and grass, but also foremost the expansion of crops and plants due to farm and forest management measures.

In total one notices that in the West African countries, with the exception of Gambia and the Ivory Coast, the forest levels have decreased markedly even though the vegetation density has increased as a whole. The field research work by Martin Brandt left concentrated on two regions: The region surrounding the city of Bandiagara in southern Mali has seen a complete transformation of its vegetation over the last 50 years: Many tree and bush types that were still common in the s have disappeared.

Periods of drought did not alone damage the plants through a lack of water, but also it was because income from agriculture fell due to poor harvests, and so the people tried to compensate by felling trees and selling lumber. However in the meantime, a vegetation-rich landscape has since appeared — and not only because the precipitation amounts have been increasing for two decades and extended periods of droughts have failed to occur.