Drylands Of Africa Research Articles

Potential pathways of indole acetic acid (IAA) biosynthesis in Euphorbia abyssinica

Desert candle (Euphorbia abyssinica J.F. Gmel.) (further referred to as EAG) is a succulent tree of dry deciduous and evergreen montane forest, woodland and shrub savanna. It occurs widely throughout dryland Africa, where it is appreciated as a live fence because it is easily propagated from untreated mature branch cuttings.Earlier we argued that the ability of large EAG branches to regenerate with ease in dry soil may be related to the natural plant growth regulator hormone indole acetic acid (IAA) contained in the latex of the plant. EAG latex samples from northern Ethiopia (n = 3) that were chemically analyzed contained on average 0.06 mg/l latex, as well as the IAA metabolites indole lactate (ILA) and indole ethanol (IEt). One sample also contained IAA conjugated to amino-acids and to glucose. Here we present a schematic overview of the potential pathways of IAA biosynthesis in EAG and suggest that auxin biosynthesis in EAG is tryptophane (Trp) dependent.

One Leg or Two? Food Security and Pastoralism in the Northern Sahel

Should pastoralists in dryland Africa diversify or specialize in their productive activities? To investigate this question, we analyze data from a consumption survey and two surveys of the nutritional status of children in addition to qualitative interviews comparing nomadic and sedentary population groups in the Gourma area in northern Mali. We show how the children of pastoralists seem to be better nourished than children of sedentary farmers and that the children of the sedentarized nomads seem to be the worst off. Based on these findings, we first argue that sedentary farming appears to be a poorer adaptation than nomadic pastoralism in arid environments such as the northern Sahel. Secondly, we argue that the diversification argument (better to stand on two legs than one) is flawed for mobile pastoralists in the northern Sahel because the logistical and organizational costs of combining different modes of livelihood are large and easily become insurmountable for a single household.

Securing access to drylands resources for multiple users in Africa: A review of recent research

This review discusses persistent tensions in efforts to secure land rights in Africa's drylands. Some researchers and practitioners advocate for formal, legal recognition of group rights as a way to secure access for drylands resource users. Others, on the other hand, speak against formal, legal protections. They argue that much of Africa's drylands are collectively held, often under customary tenures. Statutory law may undermine the dynamism, flexibility and inclusiveness of such tenures. By reviewing innovative efforts at securing access in different parts of Africa, the paper shows that any attempt to secure access for multiple users in drylands environments needs to identify frameworks for negotiated conflict resolution, crafting rules from the ground upwards, in addition to a more generic identification of rights. Policy-makers can thus focus on process, as well as the content of tenure arrangements, reconciling statutory rights with customary rights. For rights to be meaningfully secured, however, there is need to identify the nature and sources of threats that create insecurities and tailor policy solutions to threats. Elite capture and exclusion of women and young people continue to pose significant challenges in such decentralized processes.

Water points and their influence on grazing resources in central northern Namibia

AbstractDebate among scientists about ecological dynamics and appropriate management of semi‐arid rangelands has led to a challenge of received wisdoms of range management and pastoral development in dryland Africa. In our study, we investigated impacts of grazing on grass composition around permanent water points along a pipeline and around a traditional hand‐dug well in an important grazing area in central northern Namibia. Grass species abundance and selected environmental variables sampled along transects radiating out from these water points were analysed using Canonical Correspondence Analysis (CCA). Significant grazing‐induced changes, manifested by palatable perennial grasses being replaced by less palatable annual grasses, were identified around water points along the pipeline. There annual grasses Schmidtia kalihariensis and Aristida stipioides dominate the vegetation as far as 5 km from the water points. No significant grazing‐induced changes in grass composition were observed around the hand‐dug well. Private ownership leading to stronger control of access to traditional wells compared to the open access water points along the pipeline seems to be a key factor preventing overutilisation of grazing resources around the former. Copyright © 2007 John Wiley & Sons, Ltd.

Prediction of desiccation sensitivity in seeds of woody species: a probabilistic model based on two seed traits and 104 species.

Seed desiccation sensitivity limits the ex situ conservation of up to 47 % of plant species, dependent on habitat. Whilst desirable, empirically determining desiccation tolerance levels in seeds of all species is unrealistic. A probabilistic model for the rapid identification of woody species at high risk of displaying seed desiccation sensitivity is presented. The model was developed using binary logistic regression on seed trait data [seed mass, moisture content, seed coat ratio (SCR) and rainfall in the month of seed dispersal] for 104 species from 37 families from a semi-deciduous tropical forest in Panamá. For the Panamanian species, only seed mass and SCR were significantly related to the response to desiccation, with the desiccation-sensitive seeds being large and having a relatively low SCR (i.e. thin 'seed' coats). Application of this model to a further 38 species, of known seed storage behaviour, from two additional continents and differing vegetation types (dryland Africa and temperate Europe) correctly predicted the response to desiccation in all cases, and resolved conflicting published data for two species (Acer pseudoplatanus and Azadirachta indica). This model may have application as a decision-making tool in the handling of species of unknown seed storage behaviour in species from three disparate habitats.

Response: Forwards to New Challenges, Not Backwards to Prescription

Jules Siedenburg (in this issue of DPR) has misunderstood the purpose of our 1994 book, which was to differentiate between long-run forces of change and the impact of particular projects. The methodology we adopted is rehearsed in this response, as it authenticates our data. His attack on our use of price data is rebutted. From our data we expanded our original model and derived the policies that had encouraged farmer investment and technology change. Our work can be rebutted if these policies fail, not by the mere existence of continued degradation or failure to adopt particular technical recommendations. We have since tested our model in comparable areas of dryland Africa, and the cited works by others generally support our findings.

Climate Change and the Challenge of Non-equilibrium Thinking

Climate change is happening, that much is certain. But in what way? How much? And with what impacts? Complex, non-linear models try to predict trends and patterns, but, inevitably, each model is different, parameters are difficult to estimate and the precise impacts remain uncertain. We live in an uncertain world, one where the knowledge about both likelihoods and outcomes remains uncertain. The striving for increased predictive power over the consequences of climate change has yielded results in the past few decades. We clearly know a lot more than we did. But this is not enough to allow climate science to inform people to direct the future. While global circulation models and forecasting approaches will improve with better technology, more empirical data and faster numbercrunching capacities, the nature of climate–ecosystem interactions is such that non-linearity and the complexity of dynamic interactions means that uncertainty will always be present. This article explores the implications of this, drawing lessons from the drylands of Africa, where non-equilibrium thinking has challenged conventional approaches to pastoral development.

Long-term change in African drylands: can recent history point towards development pathways?

The problem of poverty in Africa was often discussed in terms of the agro-ecological specifics and the internal social relations of societies, production systems and economies. It appeared necessary, therefore, for states and international organizations to intervene. Because poverty was identified with production constraints, such interventions took the form of technological transfer in agriculture. Later, as agro-ecological constraints became more widely perceived, and supposedly “fragile” ecosystems were believed to be under threat from population growth and other factors, emphasis shifted to “environmental sustainability”. As with the new technologies, so with sustainable natural resource management, it was often assumed that the new knowledge must come from outside, or from “science”, and must be promoted against the natural “conservatism” of smallholders by whatever means necessary—from coercion at one extreme to “participation” at the other. Recently there has been much movement away from such stereotypical positions towards more subtle and varied statements of the problem. However, I believe there is still a lacuna with respect to the autonomy of the smallholder in the “fight against poverty”. Intervention is still the name of the game, and receives far more attention than the resources or achievements of poor people themselves. Analyses of long-term trends in the management of resources at the village, regional and national levels in dryland Africa suggest that African farmers have made considerable achievements in the face of a trying environment. An understanding of this long-term trend may provide a better framework for the diagnosis of current problems and the formulation of future policy on poverty and livelihoods in the drylands.

Regional perspectives on agriculture and biodiversity in the drylands of Africa

This is a keynote paper focusing on regional perspectives on agriculture and biodiversity by exploring the situation in Northern Africa, the West African Sahel, East Africa and the Horn, and Southern Africa. The paper establishes that in all these regions agriculture accelerates loss of biodiversity because of attempts by farmers to increase crop and animal production to feed the increasing population and contribute to the growth of the national economies. Harmful agricultural practices, such as overcultivation, overgrazing, bush fires, cultivation of marginal and easily eroded land, mechanization and the widespread use of chemicals and pesticides, have intensified the degradation of the soil and vegetation and led to rapid decline of species types and their numbers. Agriculture and biodiversity can be complementary activities. If properly managed, agriculture should enhance and not be the enemy of biodiversity in the drylands of Africa. There is need to assess the agricultural potential of the semi-arid environments and develop specific agricultural policies or programmes to enhance their sustainable utilization and conservation of biodiversity. Information contained in this paper was gathered from the existing literature

Livestock Market Dynamics and Local Vulnerabilities in the Sahel

As institutions that facilitate the conversion of livestock to grain and adjust livestock populations to local forage availabilities, livestock markets play important economic and ecological roles in dryland Africa. Using a comprehensive database of 1,580 sales of livestock owned by members of 54 households in western Niger over a major drought-and-recovery cycle (1984–94), the effect of real livestock markets on stocking decisions and the economic vulnerability of rural households was investigated. While livestock markets are shown to facilitate destocking of animals from drought areas, price formation is socially-biased (by gender, wealth, residence) reflecting the differential access and powers within local markets.

Camel Husbandry Practices in Eastern Ethiopia: The Case of Jijiga and Shinile Zones

Introduction In Ethiopia, as in most dry lands of Africa and Asia, camels are the principal source of income and food for millions of pastoralists. In addition, camels play a central role in providing draught power and determining the wealth and social status of pastoralists. Ethiopia's camel population is estimated to be one million head (FAO 1996a). This number ranks the country third in Africa after Somalia and the Sudan, and fourth in the world (India included). Camels inhabit almost all peripheral drier lowlands that generally fall below 1,500 metres above sea level in Ethiopia, except the western areas where high humidity and the incidence of trypanosomiasis are common (Teka 1991; Tekel 1989; Wilson 1989b). These areas include the major parts of the Somali and Afar National Regional States and some parts of the Oromia National Regional State. (1) Afar camels are small but extremely hardy and, except for some used for salt transport, are kept almost entirely as milk producers. Ethiopia's largest camels are of the Ogaden type, owned by the Somali in the east of the country. These are also almost entirely used for milk production and only rarely for transport, except to move the household and its goods and chattels when changing camps. Borena camels (found in the Oromia National Regional State) are of intermediate size and are employed as pack, draught and dairy animals. The eastern part of Ethiopia is considered the heartland of the camel population, because it is home to two-thirds of the nation's camels (CSA 1988). Although the contribution of camels to the national economy is not fully quantified, Schwartz (1992) estimated that 20,000 tonnes of camel meat and 174,000 metric tons of camel milk were produced annually in the country. Even though Ethiopia possesses a large number of camels, little is known about camel husbandry practices or the productive and reproductive performance of camels (Teka 1991; Tekel 1989; Wilson 1989b). Given this state of affairs, this study was designed and executed as one component of the European Camel Project (ECP). (2) The results of this study are expected to provide basic information on the household characteristics of camel herders, as well as on herd demography, reproductive performance of camels and the constraints affecting the entire camel husbandry system in eastern Ethiopia. The rest of this paper is organised in three sections. Section I presents the research design and methods of data collection and analysis. Section II discusses the findings of the study. Section III concludes by discussing policy implications. Section I: Methodology Description of the study areas This study was conducted in the Somali National Regional State (SNRS), which is located in eastern Ethiopia. It is one of the nine ethnically based regional stales of the country and it is divided into nine zones. The total population of the SNRS in 1999 was estimated to be 3.6 million (5.84 percent of the country's population), of which the overwhelming majority (85 percent) is rural (MEDaC 2000). The population density of the region is 9.6 persons per [km.sup.2], as compared to the national figure of 49.3 persons per [km.sup.2] (MEDaC 2000). According to CSA (1999a), the predominant ethnic group in the SNRS are the Somali (95.7 percent), followed by the Oromo (2.3 percent), the Amhara (0.7 percent), the Guragie (0.14 percent), the Tigrie (0.05 percent) and the Sidama (0.03 percent). The percentage distribution by religion shows that 98.7 percent are Muslims, the remaining being Christians (1.1 percent) and followers of other belief systems (0.2 percent). The same source indicates that the Somali ethnic group, which accounts for 6.3 percent of the entire country's population, is the third most important ethnic group in the country, next to the Oromo (32 percent) and the Amhara (30 percent) The language most widely spoken in the SNRS is Somaligna, which is the language of the Somali ethnic group. …

Conflict, Environmental Change, and Social Institutions in Dryland Africa: Limitations of the Community Resource Management Approach

In dryland Africa, development attention has shifted toward community resource management projects. The concurrence of environmental degradation, resource conflict, and "weak" resource management institutions is seen by project managers as evidence for the failure of local institutions to govern resource use. This article demonstrates that such diagnoses are error prone and are often logically reducible to the simple advocation of the formalization of resource access. "Community based" projects, such as those following the Gestion de Terroirs approach in Sudano - Sahelian West Africa, often attempt to improve resource management by spatially delimiting appropriate land uses, strengthening the community's exclusionary powers, and clarifying specific claims to village resources. Based on research within agropastoral areas in Mali and Niger, this article argues that rigid adherence to such development templates runs the risk of increasing local ecological and economic vulnerabilities. Multiscaled, comanagement approaches that better utilize informal networks and political institutions to mediate resource access are proposed as alternatives.

The nature, causes and consequences of desertification in the drylands of Africa

The dryland environment of Africa poses formidable problems for sustainable development. Among these are unpredictable and severe drought, desiccation or aridification due to persistent drought and dryland degradation or desertification. Because these problems overlap in their effects on the ground, often those who seek sustainable development for these drylands tend to view the problems as one and the same. Yet to facilitate the development of appropriate and effective mitigating measures it is important that the differences and interrelationships be clearly understood. This article starts by outlining the differences and interlinkages between desertification, drought, desiccation and climate change and their causal factors. The central theme is the human causes and consequences of desertification in the drylands of Africa. An attempt has been made to unravel the changing views on the human causes, this is followed by a brief outline of the intervening plans and actions to stem the problem. A significant drawback in combating desertification and drought is the failure of African governments to devolve power to the people who are affected, and to link environmental degradation to economic policy. Consequently, many programmes lack local support or are undermined by conflicting trade and agricultural policies pursued by governments. It is contended that, for sustainable development strategies to work, policies should put the welfare of the people in these drylands at the centre of the development agenda and give them the rights and the power to determine their future. They should empower the people to sustain adaptive strategies towards sustainable livelihoods. Also the threats posed to environment and sustainable development by protectionism and overconsumption in the north and structural adjustment programmes (SAPs), call for the removal of distortions created by the import barriers of developed country, the curbing of overconsumption and a fundamental revision in the structure of SAPs to help alleviate poverty and protect the environment in these African countries. It is in the interest of the global community that the environment in Africa is protected. © 1998 John Wiley & Sons, Ltd.

New approach in research education to solve problems of dryland farming in Africa

For quite some time now, Africa has faced food shortages that are largely due to deterioration of agricultural environments and high population growth rates, leading to a combination of production pressures. The agricultural problems are particularly pronounced in dryland farming, and the means to mitigate them have to be mainly of a low external input nature. A case study from Kenya of an integrated research education approach holds much promise for contributions to solve such food production problems in the drylands of Africa and other low external input sustainable agriculture (LEISA). The approach emphasizes interdisciplinary research education of local scientists by problem‐oriented research in tackling environmental hazards facing the farmers. Six primary sequential steps, from problem identification via field quantification to the contributions to solutions, are distinguished as essential. In the Kenyan example, it was possible to give a “weather advisory,”; that is, an extension message with strong agroclimatological components, on the biophysical and economic limits of alley cropping Cassia siamea with maize in a semiarid environment. Adaptation requirements of some commercial instruments under tropical conditions were also covered. Such a range of subjects is essential if research education is to contribute to protection from environmental hazards in dryland farming.

Struggle for control over wetland resources in Zimbabwe

Wetlands are key resources for both agriculture and grazing in the drylands of Africa. They are often central to local contests for control and access. The article examines the struggle for control over wetland resources in Zimbabwe by exploring means by which different local actors have made claims over dambo resources for both agriculture and grazing. The impact of the state, mediated through environmental legislation, technical research, and development projects, is also examined. A case study of resource management conflict is presented that highlights the political and economic dimensions of wetland control for grazing use.

New directions for pastoral development in Africa

The last few years have seen a major rethinking of some of the hallowed assumptions of range ecology and range-management practice. The usefulness of terms such as ‘vegetation succession˚s, ‘carrying capacity˚s, and ‘desertification˚s is being reassessed, particularly for the dry rangelands which are dominated by highly variable rainfall and episodic, chance events such as drought. This article examines the management and policy implications of this thinking for pastoral development in dryland areas. It briefly examines the consequences of environmental variability for pastoral development planning, range and fodder management, drought responses, livestock marketing, resource tenure, institutional development, and pastoral administration. By offering new directions for development workers, researchers, and policy planners, the article illustrates, in practical terms, a future for pastoral development in dryland Africa that recognises both the importance of pastoral livelihoods and the significance of envi...

Soil productivity, soil conservation and land evaluation

ICRAF's main contributions to research related to soils have been a symposium, Soils Research in Agroforestry; a review of soil productivity aspects of agroforestry; a further review of the potential of agroforestry for soil conservation, covering both erosion control and maintenance of fertility; the construction of a computerized model to predict soil changes under agroforestry systems; and a handbook of practical methods of agroforestry for soil and water conservation in dryland Africa. In research on land evaluation, an environmental data base has been established, leading to a capacity to obtain information, for environmental conditions similar to those of a given site or area, on publications, multipurpose trees, crops, existing agroforestry systems and current experimental work. Land evaluation for agroforestry cannot be achieved merely by synthesis of methods from agriculture and forestry, but will require more data on the performance of agroforestry land utilization types. Recognition of problems of environmental degradation has become an integral part of planning for agroforestry research. By means of a partial synthesis between land evaluation and diagnosis and design, a procedure of site selection for agroforestry research and development has been established.