5.3 Focus: Rangeland management and issues in Africa

Agroclimatic environment of rangelands

Rangelands are a land-use category in which pastoralists and their livestock play a significant, and often predominant, part in the agricultural economy. Rangelands typically occur in the dry-lands bordering the general areas of the Sahara and the Kalahari deserts, with rainfall amounts between virtually nil to 750 mm (figure 5.5).

Figure 5.5. Major semi-arid precipitation zones in Africa

Note: The red line indicates the limit of the 180-day growing season. It is based on the 1961-90 reference values from GAEZ (GAEZ, 2012); the precipitation grid is from the WORDCLIM database (Hijmans, 2005).

According to the authors of the African Union sponsored report on the rational use of rangelands and fodder crop development in Africa (Inter-African Bureau for Animal Resources, AU-IBAR 2012; an important source for several sections of this note), “dry-lands” are better defined by the length of the rainless period than by rainfall amounts. This is because of seasonality (two or more rainy and rainless periods); the relations between evapotranspiration, temperature, and elevation; and rainfall distribution patterns over the year. The common definition of dry-lands puts the length of the rainless period at 180 days, which often allows for some combination of crop agriculture and livestock husbandry. When, however, rainfall drops below 200 or 250 mm, most crop farming without irrigation becomes mostly impossible or, at least, extremely risky.

It is stressed that, contrary to the arid Sahara, most of the Kalahari “desert” is, in fact, semi-arid: precipitation is generally between 250 and 500 mm (Figure 5.5, centered around Botswana). In many ways, the region is comparable to the Sahelian zone in West Africa, and it is frequently covered by sparse “forest.” The Namib desert, which includes the border area between South Africa and Namibia, from the coast to southwest Botswana, is the driest area of he Kalahari; it is mostly sand desert akin to much of the Sahara.

Dry-lands (delimited by the 180-day season line in figure 5.5) make up 43 percent of Africa’s inhabited surface and are home to 40 percent of the continent’s population. Dry-lands include areas that are climatically sub-humid, semi-arid, and arid in the BS, BW, and CW classes in the Köppen Climate Classification System. In parallel with the decreasing gradient of rainfall, the economy changes from agro-pastoralism to pure pastoralism. As stressed above about the Kalahari “desert,” the vegetation of African rangelands reflects amounts of precipitation and may include mixed woodland/grassland “forest” (miombo), shrub-lands, and grasslands. AU-IBAR (2012) stresses that in African dry-lands, dwarf shrubs account for a larger share of cattle nutrition than perennial grasses.

Another defining feature of African dry-lands is the variability of rainfall, which affects all facets of precipitation distribution: spatial, intra-seasonal, and inter-seasonal. Rainfall variability is the main source of risk in all African cropping and livestock production. As illustrated in figure 5.6, both the driest (arid) and wettest (equatorial) areas enjoy low variability. The largest inter-annual variability occurs in the driest areas in east Africa (especially the Horn of Africa), southern Africa, and southern Madagascar. In comparison, the Sahel enjoys relatively low variability.

Figure 5.6. Standard deviation (in days) of the length of the growing season over the reference period 1961-1990

Source: Based on gridded data in GAEZ (2012).

Varying degrees of nomadism

In the driest areas, rangeland management becomes an exercise in optimizing the use of scarce and dispersed biomass resources using the mobility of livestock. Livestock harvests an irregularly distributed resource, provided sufficient biomass and watering points are available to maintain the livestock healthy. It has been argued that pastoralism outperforms ranching in terms of returns (in cash) per hectare, meat production, and energy generation as firewood and cow-dung (de Jode 2010).

Somehow, at least in the driest areas, livestock production and rangeland management systems never reach equilibrium. The whole society and social arrangement, including land ownership and the nomadic live-style, are aimed at optimizing survival in the face of the extreme variability of resources.   

Nomadism essentially occurs at two spatial scales. At the largest scale, herders and their cattle follow the movements of rainfall-generating weather systems. These are the same systems that also condition the timing and number of rainy seasons in tropical areas, essentially the Inter-tropical Convergence zone (ITCZ); the same systems also trigger the spectacular migration of large wild ruminants in eastern Africa (figure 5.7).

Figure 5.7. Migration of gnus (wildebeest) in East Africa

Source: https://commons.wikimedia.org/wiki/File:Wildebeest_Migration_in_Serengeti_National_Park,_Tanzania.jpg.

The ITCZ corresponds approximately to the “thermal equator,” which is the latitudinally variable band area where highest temperatures are recorded [footnote 1]. Trade winds (blowing from the east) converge at the ITCZ and rise, thereby cooling and generating clouds and rainfall. Precipitation does not occur exactly at the position of the ITCZ, but usually 200 or 300 km closer to the geographic equator than the thermal equator. Throughout the year, the position of the ITCZ changes, with the zone being in the southern hemisphere in the months around January and in the northern hemisphere in the months around July (figure 5.8). The intensity of the color in the figure indicates the frequency of the presence of the ITCZ, highlighting the considerable uncertainty (inter-annual variability) that exists for the position of the ITCZ, which is a fundamental variable for rangeland and cattle monitoring, management, and information systems (figure 5.9). According to Sachs and Myhrvold (2011), current data indicate that climate change could entail a shift of the average position of the ITCZ by up to 5 latitudinal degrees, which would completely modify current cropping and rangeland patterns in Africa. It can be assumed that this would “re-green” the Sahara but turn the Kalahari into a true BW desert in the Köppen Climate Classification System.

Figure 5.8. Average position of the ITCZ during July (red) and January (blue)

Source: https://upload.wikimedia.org/wikipedia/commons/d/d7/ITCZ_january-july.png.

Figure 5.9. Position of the Inter-tropical front (red) during the third dekad of October 2017

Source: ITCZ monitoring by NOAA, http://www.cpc.ncep.noaa.gov/products/international/itf/itcz.shtml.

The large-scale nomadism that is associated with the large movements of the ITCZ is usually referred to as transhumance. In addition to transhumance, there is also micro-nomadism, with cattle movements occurring within a limited region, especially during the rainy season in areas where this season lasts more than a couple of months. Many potential conflicts derive from the interaction during at least part of the year between crops and cattle, farmers and herders. Unless they are given feeds, animals need to move in search of biomass and water.

Characterization of livestock and rangelands in African economies

Grazing lands (rangelands combined with permanent meadows) occupy between 21 percent (in the middle of Africa) and 57 percent (in the south of the continent) of the total land area of African countries [footnote 2]. When considering agricultural land only, the percentages increase to 30 percent in the middle area to as much as 91 percent in southern Africa and around 70 percent in remaining areas (table 5.4). As shown in the table, these percentages have been decreasing over the last 15 or so years, especially in the east, while they have remained stable in the south. This finding is consistent with Nkonya et al. (2013), which stresses the increase of croplands at the expense of other land uses, including wetlands and “forest.”

Table 5.4. Select statistics about rangelands and cattle in Africa

Notes: Imports and exports refer to live animals. Prepared with data extracted from FAOSTAT. For a list of countries in each region (North-South), see footnote 2. 
[1] Beef cattle, camels, pigs, goats, and sheep, in millions, average 2010-14 numbers; [2] Change from 2001-5 to 2010-14 in percentage; [3] percentage point change from 2001-5 to 2010-14; [4] Livestock Unit (LSU) density in the agricultural area in LSU/hectare; [5] Percentage change between 2001-5 and 2009-13.

Livestock numbers are very similar to those of the human population throughout most of the continent, with the exception of central and eastern Africa where animals outnumber people by a factor of two to three. With the exception of the north and south, numbers have increased markedly over the last decade, up to 54 percent in east Africa, which includes some of the areas with large potential of conflicts because of human concentrations and large environmental variability (Figure 5.6).

Goats and sheep numbers generally exceed beef populations by a factor of two to three. This is explained by various factors that include the robustness of small animals and the preference for small amounts of meat when animals are slaughtered, as large volumes cannot be easily stored and need to be consumed immediately. In general the share of beef has been decreasing over the last decade. Other animals are also kept in Africa but nowhere reach the importance of the listed ruminants. They include water buffaloes (mostly in Egypt, FAO 2017a), camels, and pigs. Camels reach 3 percent in north and east Africa and--with the exception of north Africa where they are absent--pigs make up about 3 percent too, except in middle Africa where they reach 10 percent.

Table 1 also lists the density of livestock units (LSU) because the variable is a good measure of the pressure put on rangelands by the animals. An LSU [footnote 3] is, somehow, a measure of the “grazing power” of animals. A “modern dairy cow” is assigned a LSU value of 1, while FAO assigns tropical cattle a lower value of about 0.7. The small ruminants count as approximately 0.1, while camels reach or exceed 1.0. The LSU density, therefore, is a direct measure of the grazing pressure on agricultural land. Values are highest in east Africa (0.22 LSU/hectare) and lowest in the middle and south of the continent with values below 0.1 LSU/hectare). Much literature of the 1990s (for example, World Bank 1995) focused on the concept of Carrying Capacity (CC) of rangelands, which is the number of LSU a given area can sustain. It appears that the carrying capacity is difficult to handle when both livestock and biomass vary considerably over time due to the inherent variability of arid-lands, and equilibrium is never reached.  

Most countries in Africa have a trade deficit in terms of live animals and meat products, with the exception of countries in the middle of Africa and, especially, east Africa. The latter region exports cattle mostly to the neighboring Arabian peninsula.

Problems and issues related to rangeland management in Africa

The sections above have stressed that livestock and the exploitation of rangelands are important sectors of the economy in most African regions. Many problems do, however, arise because of the risks connected with the exploitation of a spatially and temporally variable resource using mostly traditional techniques that compete with other sectors. Several good syntheses of the issues facing livestock and rangelands in Africa have been developed by the African Union (the already mentioned AU-IBAR of 2012), FAO and the CGIAR centers, especially ILRI (International Livestock Research Institute, Nairobi), and the World Agroforestry Centre (a brand name used by the International Centre for Research in Agroforestry, ICRAF, also based in Nairobi).

Restrictions to the short-range movements of cattle

Land, including grazing lands, is often collectively owned in Africa. Where this is the case, the lands are managed by traditional authorities who may assign parts to other uses, such as crop agriculture. The land use changes are driven by population and “development,” such as construction, establishment of ranches, and large scale agriculture. This has frequently led to land fragmentation, a decrease of land available to herders, and impediments to free cattle movements. This, in turn, has entailed the degradation of rangelands and the over-exploitation of water resources. Conflicts frequently erupt in rangelands due to a variety of factors, including cattle rustling (stealing) and the weakening of traditional authorities, which generally results in ambiguous rights. Fencing of rangelands or croplands is now common, and farming tends to substitute other land uses including wetlands, which are essential for cattle survival during the dry season.

As mentioned above, woody biomass is a source of food for cattle that is as important as herbaceous vegetation, and fuel-wood collection by villagers (which has been increasing) directly competes with cattle. This is often compounded by refugee fluxes who also need fuel-wood and bring some cattle with them. Finally, livestock competes with wildlife for rangelands outside of protected areas, while livestock is not permitted into parks, many of which actually constitute the traditional herding areas or nomads in the low rainfall areas.

Limits to long-range (transhumance) movements

Most African countries are gradually introducing border controls in areas where transhumance had traditionally taken herders and their livestock across those border areas well before their establishment. Fortunately, recognition of the ecological and economic efficiency of pastoral land management is growing. Most regional associations (such as ECOWAS, EAC, and COMESA) have provided or work at developing a framework to enable trans-boundary movements of cattle in the form of International Transhumance certificates, which provide for the registration of the movements of herders and the identification of their cattle (ECOWAS 2017).

Land degradation and desertification

Overgrazing and the gradual decrease of the capacity of plant biomass (natural vegetation) to regenerate is one of the facets of land degradation. Many dry-lands, however, suffer from various types of degradation, including soil erosion, loss of biodiversity, salinization, and unsustainable use of water. According to some estimates, about three quarters of African rangelands are somehow degraded. Desertification is defined as land degradation in semi-arid areas. Its causes include the direct actions of humans in the area, but also, and to a growing extent, the effects of climate change.

Solutions?

Innovative systems have to be designed to tap the biomass of rangelands in a sustainable way, to ensure the preservation of traditional pastoralist knowledge, and to optimize the interaction between crop agriculture and herding. The whole community must be involved to ensure collective ownership of solutions. It is also essential to halt the impoverishment of nomads due to the loss of their traditional live-styles. This includes schooling systems suitable for nomadic children, as well as payment for environmental services, such as ecotourism, watershed management, water harvesting, and the sustainable management of the interface between wild animals and livestock.

There has been an increase in integrated crop-livestock systems, for instance when livestock can graze on crop residues, with the fields benefiting from cow dung as fertilizer. While clearly mobility must be regulated and coordinated with crop farmers and among pastoralist groups, additional solutions may come from multilateral environmental agreements such as the Convention to Combat Desertification (UNCDD), the Convention on Biodiversity (UNCBD), and especially the Framework Convention on Climate change (UNFCCC), using the mechanisms of carbon sequestration. Techniques suitable to store carbon in soil in rangelands would be of huge relevance considering the size of rangelands and the benefits associated with increased carbon, including improved soil fertility and better soil moisture storage capacity. According to Milne et al. (2016), relatively simple management techniques can contribute to improve soil carbon in sub-Saharan grazing lands. The international agreements are of direct relevance to dry-lands and the associated livelihood systems.

New communications and observation technology can play an essential part in surveillance of rainfall and biomass, and the optimized management of rangelands and cattle. This could result in the rehabilitation of and improved conservation of rangelands, as well as the maintenance of biodiversity through controlled grazing, fire-control, rotations, and reseeding when required. Eventually it will also be necessary to adopt modern management techniques for rangelands and cattle, including animal health and breeds, as well as improved fodder production (which may involve trees and shrubs, Opuntia, and grasses). Improvements are also needed for the marketing of rangeland products (such as meat, milk, skins, wool, medicinal herbs, and other plants such as frankincense and gum Arabic, honey, and minerals).

According to FAO (2017b), per capita milk consumption decreased in sub-Saharan Africa over the two last decades. Compared with other regions of the world, milk consumption is medium (30 to 150 kg per capita per year) in northern and southern Africa and Kenya, and low (below 30 kg per capita per year) in most of central Africa. Milk provides 3 percent of the dietary energy supply in Africa, compared with 8 to 9 percent in Europe and Oceania, and 6 to 7 percent of dietary protein supply in Africa, compared with 19 percent in Europe. Milk is just one of several livestock products that has a good potential for development in Africa.

Conclusions

African rangelands are a huge resource at the continental scale. Because they occupy mostly dry-lands with low vegetation density, the use of small ruminants and beef cattle constitutes a well-tested and efficient form of  biomass harvesting, as demonstrated by the importance of livestock in the economies of most African regions. Unfortunately, the harvesting of sparse biomass implies the mobility of cattle and their herders, at scales varying from local to international in the traditional transhumance movements by which cattle follow the rain. With economic development, the increase of crop agriculture and other land uses, cattle movements are more and more restricted, creating or fueling conflicts. This is compounded by climate change and--partially human-made--land degradation. The pastoralists’ way of life has apparently become less sustainable, while their populations became impoverished. Yet, solutions and opportunities do exist. They imply technical improvements to the husbandry of livestock and rangelands, agreed and mutually beneficial arrangements between farmers and herders, improved ease of movement across borders, and the optimization of grazing through modern communication and observation techniques.

References

AU-IBAR 2012. Rational Use of Range-lands and Fodder Crop Development in Africa, AU-IBAR (African Union – Inter-african Bureau for Animal Resources) Monographic Series No. 1, Nairobi, Kenya.

ECOWAS 2017 http://www.ecowas.int/ecowas-stresses-the-need-to-obtain-international-transhumance-certificate/

FAO 2017a http://www.fao.org/dairy-production-products/production/dairy-animals/water-buffaloes/en/

FAO 2017b http://www.fao.org/dairy-production-products/products/en/; http://www.fao.org/ag/againfo/themes/en/animal_production.html

GAEZ 2012. GAEZ  ver 3.0, Global Agro-ecological Zones Model Documentation available from http://www.fao.org/fileadmin/user_upload/gaez/docs/GAEZ_Model_Documentation.pdf and from http://www.gaez.iiasa.ac.at/docs/GAEZ_User_Guide.pdf

Helen de Jode 2010. Modern and mobile, The future of livestock production in Africa’s dry-lands. International Institute for Environment & Development (IIED) and SOS Sahel International UK.http://pubs.iied.org/pdfs/12565IIED.pdf

Hijmans R, S E Cameron, J L Parra, P G Jones, A Jarvis 2005 Very high resolution interpolated climate surfaces for global land areas. Int. J. Climatol. 25:1965–1978

Milne E, E Aynekulu, A Bationo, N H Batjes, R Boone, R Conant, J Davies, N Hanan, D Hoag, J E Herrick, W Knausenberger, C Neely, J Njoka, M Ngugi, B Parton, K Paustian, R Reid, M Said, K Shepherd, D Swift, P Thornton, S Williams, S Miller , E Nkonya 2016 Grazing lands in Sub-Saharan Africa and their potential role in climate change mitigation: What we do and don't know. Environmental Development 19:70–74

Nkonya E, J Koo, E Kato, Z Guo 2013 Trends and patterns of land use change and international aid in sub-Saharan Africa. UNU-WIDER Working Paper No. 2013/110, United Nations University, https://harvestchoice.org/sites/default/files/downloads/publications/WP2013-110.pdf

Sachs J, C L Myhrvold 2011 A shifting band of rain. Scientific American, 3:60-65  

WB 1995 Pastoral Rangelands in Sub-Saharan Africa :Strategies for Sustainable Development. http://www.worldbank.org/afr/findings/english/find4O.htm

Footnotes

[1] This latitude corresponds approximately to the declination of the sun.

[2] The groups of countries categorized  under North, West, East, Middle and South Africa are those adopted by FAOSTAT, as follows: “Middle: approximately corresponds to central equatorial Africa, but East Africa extends south as far as Zambia, Zimbabwe and Malawi, which leaves only five countries in the South. West includes the Sahel and the Gulf of Guinea countries and corresponds approximately to ECOWAS. Using the three-letter ISO-3166 code for countries (https://en.wikipedia.org/wiki/ISO_3166-1_alpha-3), the exact grouping is as follows: North Africa: DZA, EGY, LBY, MAR, TUN; West Africa: BEN, BFA, CPV, CIV, GMB, GHA, GIN, GNB, LBR, MLI, MRT, NER, NGA, SHN, SEN, SLE, TGO; East Africa: BDI, COM, DJI, ERI, ETH, KEN, MWI, MOZ, RWA, SOM, SSD, UGA, TZA, ZMB, ZWE as well as the large (MDG) and small Indian Ocean islands (MUS, MYT, REU, SYC); Middle Africa: AGO, CMR, CAF, TCD, COG, COD, GNQ, GAB, STP; and South Africa: BWA, LSO, NAM, ZAF, SWZ.

[3] https://en.wikipedia.org/wiki/Livestock_grazing_comparison.