Role of Livestock Grazing in Sustainable Use, Naturalness Promotion in Naturalization of Marginal Ecosystems of Southeastern Spain (Andalusia)

Abstract

Southeastern Spain is one of the driest regions in Europe, yet it is environmentally diverse, botanically rich, sensitive to wildfire, susceptible to erosion, and desertification, and in need of research, now that the Common Agricultural Policy is fundamentally changing the rural development paradigms. Our research group has been contributing to the development of methodologies and acquisition of knowledge to manage pastures and silvopastoral systems in this region since 1986. The proposed carrying-;capacity methodology provides valuable information on rangeland diversity and the nutritive value of forage species (crude protein ranges from 4.02% in Hyparrhenia hirta (L.) Stapf to 27.17% in Suaeda pruinosa Lange; metabolizable energy varies between 4.22 MJ kg−1 DM for Dorycnium pentaphyllum Scop. and 11.30 MJ kg−1 DM for Adenocarpus decorticans Boiss.), forage production of rangeland and metabolizable energy, varied from 45 kg DM ha−1 year−1 and 127 MJ ha−1 year−1 for halophytic shrublands to 3,264 kg DM ha−1 year−1 and 11,415 MJ ha−1 year−1 for medium leguminous shrublands. Comparing these figures with small ruminants' energy requirement (4,841.36 MJ SRU−1 year−1 for local breeds), we calculated the corresponding carrying-capacity values. These are needed by rangeland grazing managers. Two agroforestry- management alternatives are offered within environmental and socioeconomic constraints. First, livestock and agriculture are integrated in practices such as browsing in fodder-shrub plantations or grazing on pastures in olive and almond orchards; and second, a silvopastoral system designed for the prevention of forest fires and the promotion of naturalness in ecosystems.