Estudi dels efectes de les cremes prescrites en cargols terrestres al Parc Natural del Massís del Montgrí

Abstract

Prescribed fires are low intensity burns in a selected area, at a certain time of the year and at an appropriate interval return. It is a forest management method with numerous objectives such as preventing wildfires, creating firebreaks to protect urban areas, improving the grass layer in grazing areas, restoring habitats to their natural characteristics or for research purposes. Fires cause a drastic change in ecosystems because it reduces food and shelters, but it also allows for reproduction and coexistence of plant communities. Terrestrial gastropods are key elements in an ecosystem because many species are soil decomposers. They are vulnerable to fires for their limited mobility, which prevents them from escaping fire. Additionally, they are influenced by the environment, such as habitat structure and soil moisture. This study evaluates prescribed burns impact for abundance and richness of terrestrial snails in the Massís del Montgrí Natural Park. Six burned sections and four control areas have been sampled. A total of 433 individuals from 17 species have been collected, with 200 from the burned plots and 233 from unburned areas. Significant differences in abundance and species richness were observed between the burned and control areas. It was shown that a number of burns positively influences the abundance of large snails. On the other hand, the results show an increase in the number of small species with more leaf litter and vegetation cover. Control areas accumulate more litter due to increased forest mass, providing more resources for detritivorous species, especially the smaller ones. However, the number of individuals of large species decreases, because they can live in more environments and feed off of vegetation, which allows them to survive in burned areas better. No significant results were obtained for species richness in the GLM analysis. Therefore, it is observed that prescribed fires have a negative impact on the abundance of small species, while benefiting large species