Biological fire prevention method: Evaluating the effects of goat grazing on the fire-prone mediterranean scrub

Abstract

The effect of goat grazing on the shrubby understory of a pine forest in Doñana Natural Park was evaluated using non-destructive measures of vegetation volume over a period of twenty-four months. After establishing grazing exclusion fenced plots 350 adult Payoyas goats were introduced. Vegetation was sampled before the introduction of goats and afterwards twice a year, using the point intercept method and thereby obtaining data of height, frequency, cover and biovolume of species. After two years the total biovolume of the vegetation of the ungrazed area had increased significantly by 32.9%, while at grazed area, vegetation biovolume decreased significantly by 23.1%, leading to a significant decrease in mean height of the species. Although the number of species remained unchanged throughout the study, significant changes in their relative abundance were found in grazed area. The different responses of scrub species to grazing can be used as a tool to control species sensitive to grazing in shrubby forested areas. Significant reduction of total biovolume due to a reduction in vegetation height will help to reduce fire risk, thus contributing to the conservation of Mediterranean woodlands and forests while also fulfilling an important role in the economic and social lives of the rural population of Mediterranean countries.