Sustainable farming and food security in West Africa Jan Gunnarsson Associate Professor Emeritus

Climate change in West Africa: Declines in mean annual precipitation over the past century. Decreases in rainfall are predicted also in the future. Warming trend since the 1960s with an increase in the number of warm spells. This trend is expected to continue Unusual and unprecedented heat extremes are projected to occur with greater frequency during summer months

West Africa with the Gambia

The Gambia:

Semi-arid climate:

Total populations 2012: West Afrika (15 countries): The Gambia: South Africa:

Population growth rate (average, annual ) (UN statistics)

GDP/capita (current US $) (UN statistics)

Food production index ( =100) (UN statistics)

Aims of this lecture: Show how biological regulation of ecosystems can be used to alleviate the negative effects of climate change to increase the food security. Illustrated by agroforestry Point to cultural and social institutions that prevent or facilitate biological regulation sufficient for food security.

Supply of essential protein in West Africa: Protein we cannot produce ourselves of which food from plants tend to have relatively lower concentration than food from animals. Fish accounts for 50 % of the animal protein consumed in Ghana, Sierra Leone and in the Gambia even as high as % Nuts and legumes (cowpeas, pigeon peas) can replace meat In developing countries meat represents the most concentrated source of importance for young children

Threats to food security: Potential fish catches off the coast of West Africa is likely to be reduced by 50 % 2050 as compared with 2000 Senegal ranks among the most vulnerable countries in Sub-Saharan Africa with regard to climate change driven impacts Fresh water fisheries are destroyed as surface water temperatures are higher, evaporative water loss increases and summer stratification occurs earlier in the season. Fresh water fisheries destroyed as water flow and water levels in the lakes are reduced.

How much does agroforestry add to the adaptive capacity to climate change? Framework for assessments that includes: 1)Agroforestry system for sustainable farming 2) Neighboring ecosystems and cross-system flows and impacts 3) Cultural and social institutions affecting the supply of essential proteins

Protein limitation hypothesis Negative correlation between bush meat hunting and market fish supply. Reductions in the supply of wild animals (fish and bush animals) can be replaced by increases in livestock from agricultural production

“Whole system approach” to agroforestry Kirschenmann suggests a system with three farming practices: 1.crop-rotation (farmers grow different crops in the same area in sequential seasons) 2.A regenerative soil-conserving strategy 3.Interactive diversification.

Trees with reported crop yield increases Tree species Indigenous name Reversed leaf phenology Nitrogen fixing Phosphorus mobilization Faidherbia albida Baransango++ Grevillea robusta Silver oak + Casuarina equisetifolia Filao + Leucaena leucocephala Leucaena ++ Pterocarpus erinaceous Keno + [1[1 [[

Other trees used in agroforestry Tree speciesIndigenous nameEnvironmental task Vitellaria paradoxaKarite´Regenerate organic matter Parkia biglobosaNeto Regenerate organic matter Animal Fodder Potassium mobilization Gmelina arboreaGmelinaAnimal fodder and shade Anacardium occidentaleCashewFirebreak Senna siameaSinjangoIncreases soil pH [1] [1] Toth (2007)

Adaptive capacity from agroforestry: across- system flow and impacts 1.Tree planting reduces soil erosion and runoff. Eutrophication in lakes, rivers, and coastal waters decreases, which increases the supply of fish 2. Cashew trees as fire belts in agroforests conserve important habitats both for wild animals and for domestic livestock. 3.Crop yield increases from agroforestry increase the perceived economic value of a common pool of trees in the forest. Increased economic value encourage farmers to conserve forests and habitats for animals 4.Forests conservation depends on traditional beliefs that forests generate rainfall on farmland Offspring used in agroforestry adds economic value to the forest (cf. 3.)

Simple agroforestry: Alley Cropping

Agroforestry and adaptive capacity: role of social and cultural institutions Customary rules guide the Tayal people in Taiwan to adopt environmental friendly farming practices. in Senegal, farmers comply with a conservation principle as they believe that dense vegetation has a positive effect on the rainfall The supply of essential proteins in the Gambia depends on customary rules of smallholder farmers, who usually not keep livestock for meat consumption but as savings, insurance, for cropping activities (manure, draught) and for ceremonies