Description of typical situation
Pastoral systems are characterized by mobility, grazing of the natural vegetation as the main source of feed, and predominant use of communal lands. Herders move with their animals for feed and water to avoid diseases and to access markets. Examples of these systems are found in Sub-Saharan Africa (the Sahel, Horn of Africa), Central Asia (Mongolia) and high-altitude lands around the world. Various forms of pastoralism are distinguished: Nomadic pastoralism is defined as pastoralism with constant movement, and transhumance is pastoralism with seasonal movement often between well-defined territories. Pastoralists combining crop production at a homestead with the movement of livestock during part of the year are referred to as agro-pastoralists. Pastoral systems are found on grasslands of all continents. Herders move with species, such as reindeer, camelids, sheep, goat, and cattle in mountainous and arctic regions of Latin America, Europe, and Asia, where it is generally too cold for crop production. Most other vast grassland regions are found in tropical semiarid and arid climates, where it is too dry (most regions have < 1000 mm of precipitation annually) and too hot for crop production. So, pastoralist systems are land use systems adapted to conditions unfavorable for crop production.
For pastoralists, livestock have multiple functions: They are a store of wealth; a source of food, such as dairy products and meat; a source of draft power; a sign of social status; and a source of marketable commodities, including live animals and manure. Pastoralism is thus considered to be a livelihood strategy as well as a way of life as it completely determines the social and economic organization of the people involved and for many centuries has been an important cultural heritage of mankind. West Africa has a high number of pastoralists and will be presented as an example of pastoralism in this context. It is estimated that the world has approximately 120 million pastoralists of which 50 million reside in Africa, with 20 million living in West Africa. Since a sustainable herd size is approximately three to four cows per person, the livestock population in pastoralist herds is between 60 million and 80 million in West Africa. In West Africa, the transhumance system is the predominant form of pastoralism. The West African pastoralists generally graze their livestock (mainly ruminants and camels) on the savannah grasslands during the rainy season to benefit from the nutritious biomass and to avoid cropped areas which are mostly dedicated to agriculture and mixed crop-livestock systems. During the dry season, the availability and quality of grass in the savannahs become insufficient for livestock feeding, and herders move with their livestock to crop-producing regions to have them feed on the crop residues that remain on the land after harvest. This crop residue grazing has reciprocal benefits for the crop farmer as manure from the animals is deposited directly on the fields. This traditional symbiosis between pastoralists and crop farmers is presently confronting several challenges: reduced availability of grazing land due to the expansion of croplands, reduced access to croplands for dry season grazing because of intensified cropping (e.g. because of dry season cropping on residual water), loss of the value of manure as it is being substituted by synthetic fertilizers in intensified crop production, and reduced access to the corridors along which pastoralist move as a result of policies to curtail pastoralism, cropland expansion, and infrastructure expansion. International borders are also becoming increasingly difficult to cross for herders and their animals. As a result, crop farmers and pastoralists compete for the use of corridors, grazing lands, and croplands; conflict between them is common.
Common environmental issues
Generally, (agro-)pastoral systems are considered to be in balance with the unfavorable conditions and thus contributing to food security from very marginal lands. At the same time, pastoralist grazing is often mentioned as a risk factor for grassland degradation. Grassland degradation is observed as vegetation cover is altered (reduced or even entirely eliminated, or evolving from grass to shrub), and signs of soil erosion appear. Such degradation reduces production potential but also biodiversity, the amount of carbon stored in soils, and replenishment of aquifers. However, pastoralist herders generally take their herding decisions based on the availability and quality of the grassland vegetation to sustain their livestock’s needs. This results in a type of grazing management in which herders generally move to new grazing areas before the regenerative capacity of the vegetation is affected by the grazing. Nevertheless, in the case of land access restrictions and times of prolonged droughts, when herds gather around water bodies and watering points as a last resort for survival, severe local overgrazing may occur (Principles 2, 3 and 5).
In many dryland regions, watering points are dug as a water source for pastoral herds. This has affected traditional moving patterns in the sense that herds may stay longer around the watering points, increasing the pressure on grazing lands surrounding the watering points and the chances for overgrazing. This mostly occurs during prolonged droughts. During regular years, however, the vegetation beyond a radius of 1 km from watering points is generally not notably affected (Principles 2, 3 and 5).
Another environmental issue is the relatively high greenhouse gas (GHG) emission intensity associated with the pastoralist production of meat and milk. Livestock productivity in pastoral systems is low because of the variable- and often low-quality feeds, the high energy expenditure on walking and grazing, and the large herd sizes. Methane is the most important GHG emitted. Other contributors to GHG emissions, such as manure deposition on grasslands, land use change, manure storage and application in agro-pastoral systems, and fossil fuel use, are of marginal importance in pastoral systems. In addition, pastoralists tend to keep large herds as a coping strategy against prolonged droughts as the chances of animals surviving a long drought are higher for a larger than for a smaller herd. This coping strategy is associated, therefore, with higher emissions of overall GHGs. These higher emissions should, however, be attributed in part to the coping strategy and other services provided by the herd (e.g., transport and fiber) as opposed to the production of edible meat and milk products (Principles 2 and 3).