Interaction and synergies of environmental and anthropic factors: effects on beaches biodiversity

Sandy beaches represent a perfect example of a socio-ecological system in which the natural component provides essential ecosystem services such as protection from flooding and marine extreme events, recreational services, food provision, etc. A recent review has quantified the ecosystem services associated with beaches at approximately 90 ES. As a socio-ecological system, beaches are influenced by a dense network of feedback created by the interaction between humans and other components of the system. The issue of coastal squeeze is currently of great concern, a term that summarizes the dual pressure on coastal areas: on one hand, phenomena related to sea-level rise, and on the other, anthropogenic pressure in terms of urbanization and other activities. Phenomena such as urbanization and anthropization are, however, difficult to measure as they are conceptualized through a series of proxies that approximate them with a certain degree of uncertainty. To address this problem, we have proposed an approach using latent variables in which the drivers of the dependent variable are latent variables constructed by an algorithm that combines values from different but complementary proxies. The method was tested by attempting to model the benthic macrofauna in terms of species number and abundance on three adjacent northern Adriatic beaches. These three selected beaches share the same bathymetric, climatic, and tidal conditions while differing in levels of anthropization and urbanization. Using a database composed of field measurements of classic beach variables and qualitative values of variables such as urbanization and management, a latent variable model was set up and implemented. The results clearly demonstrate the disturbance caused by anthropogenic activity and unexpectedly reveal windows of positive interactions with the benthic fauna of sandy beaches.