Grazing management and impact in the Canary islands: Rethinking sustainable use

Abstract

On an oceanic island, the positive relationship between livestock management and biodiversity conservation is not as clear as on the mainland. In the sensitive island's ecosystems, introduced herbivores have been considered to cause devastating effects on vegetation, and be responsible for overgrazing, ecosystem degradation, and biodiversity loss. Eradication of introduced herbivores has been proposed as a conservation tool in some islands. However, this proposal needs to be carefully considered, since there are complex and established ecological interactions between native and introduced species. The goal of this chapter is to discuss the livestock management for biodiversity conservation, with special attention on the Canary Islands (Spain) as an example. We present a review of the research done on this topic in the Canaries, looking for general conclusions and explanations of the conflicting results. Much of the research is restricted in area, however, consistent works are presented that can help us to understand the answer of the environment to grazing impact on these islands. Although some negative impacts of grazing were revealed, in general they have been restricted to some specific areas or species. In those cases where goat grazing is threatening endemic and endangered populations, control of goat densities, grazing restrictions and use of fences should be encourage, however drastic measures as eradication of goats are not ecologically or socially feasible. On the other hand, grazing of small goat herds on traditionally managed ecosystems seems to be a sustainable activity, which removal have been related with a reduction in the number of species, changes in species composition and also an increase in exotic species.