Impacts et services environnementaux de l'élevage en régions chaudes

Abstract

Animal productions are now questioned by the society for their environmental impact. Emerging and developing countries are now concerned by this debate, especially because the increase in animal production in the next decades will take place in these countries, which are often situated in warm regions (including Mediterranean, subtropical and tropical areas). It is now admitted that livestock farming may result in environmental services, besides its productive function. The objective of this paper was to review and discuss environmental impacts and services in southern countries for ruminants, pigs and poultry farms and for aquaculture, and to propose possible solutions for an improvement of environmental performances. Degradation of soil and habitat requires looking for more sustainable production systems. Greenhouse gase emissions are significant in the tropics, especially with low productive systems where the amount per kg of milk or meat is taken as a reference. This emission is compensated for by carbon sequestration in grasslands; however there is a lack of accurate references in tropical countries. Farming change towards industrialization in many southern countries results in an increase in soil, air and water pollution. Extensive systems are less polluting, and lead sometimes to environmental services. Livestock farming needs water, but this is mainly «green» water related to vegetal production. The use of fossil resources (energy, phosphates, etc.) is highly dependent on the intensification of farming systems. At last, the risk of decrease in animal and vegetal biodiversity is high, in relation with deforestation and farming practices. The main farming systems in southern countries are discussed in relation with their environmental performances. Financial incentives for environmental services may result in low-impact production systems. But the alleviation of poverty and the need for feed security are major concerns which could limit the increase of environmental performances.