Bros V, Torre I, Santos X
Land snails are an important component of biodiversity but the information regarding the factors that influence their distribution is very incomplete or anecdotal in most geographic areas. In this article our aim was to uncover environmental factors that influence the distribution and diversity of a Gastropoda community in a Mediterranean Reserve (Collserola Natural Park, Barcelona). Fieldwork was conducted from 2001 to 2003, and we systematically sampled all 1 km2 UTM squares throughout the park by randomly selecting at least one 200 m2 plot within each square. We used a community-based approach to analyse the relationships between 61 Gastropod species distributions and environmental predictors by means of Redundancy Analysis (RDA). Our results highlighted that the land snail community was affected by the environmental predictors (even for short gradients), but their influence was low according to the explained variance (30 %). Climate and habitat predictors were more important than the spatial variables in determining the community composition and diversity. 48 out of 61 (78.7 %) land snail species showed significant responses to the environmental gradients with an association of specialist species with particular habitat types. Collserola is a reserve surrounded by urbanised areas and affected by multiple anthropogenic threats mostly related to habitat transformation. The high degree of specialisation within the Gastropoda community suggests that the restoration of heterogeneous landscapes would be useful to conserve and restore terrestrial mollusc diversity in Collserola. This study can help stakeholders to make decisions related to landscape planning and habitat transformation.
Journal: Ecological Research