BIODIVERSITY AND TEMPORAL DYNAMICS OF URBAN ABOVE- AND BELOW-GROUND COMMUNITIES AT SMALL SPATIAL SCALE

URBANIZATION IS ONE OF THE MAJOR THREATS TO BIODIVERSITY, ACTING THROUGH HABITAT FRAGMENTATION AND ECOSYSTEM STRUCTURAL AND FUNCTIONAL SIMPLIFICATIONS, ALTHOUGH SUSTAINABLE DEVELOPMENT POLICIES OF URBAN SETTLEMENTS ARE GRADUALLY RECOVERING GREEN AND BLUE SPACES TO PRESERVE THEM. THE DIRECT AND INDIRECT CONSEQUENCES OF THE HUMAN INTERVENTION ARE RESULTING SPATIAL PATTERNS VARIABLE OVER TIME, THAT LEAD TO THE CONSTITUTION OF A COMPLEX BUT FRAGMENTED ENVIRONMENTAL MOSAIC, WHOSE HETEROGENEITY DOES NOT NECESSARILY IMPLY NICHE DIVERSIFICATION: HENCE THE ORGANISMS FACE A HOSTILE MATRIX HARD TO COLONIZE, ULTIMATELY AFFECTING POPULATION DYNAMICS AND COMMUNITY BIODIVERSITY. DUE TO THE CO-OCCURRENCE OF MULTIPLE ANTHROPOGENIC STRESSORS THAT MODIFY COMMUNITY RULES ASSEMBLY AND DYNAMICS, THE IMPOSSIBILITY OF QUANTIFYING THE ENTITY OF EACH ANTHROPOGENIC DISTURBANCE (IN A BROAD SENSE) EMERGES, AND THE FORMULATION OF GENERALIZED MODELS WHICH CAN EXPLAIN THE ROLE IT PLAYS IN ALTERING ECOLOGICAL SYSTEMS DYNAMICS IS PREVENTED. THE PRESENT PH.D. RESEARCH AIMS TO SHED LIGHT ON THE MECHANISMS BEHIND THE DRIVERS THAT SHAPE THE PATTERNS OF THE BIOLOGICAL DIVERSITY OF ABOVE- AND BELOW-GROUND COMMUNITIES IN URBAN ECOSYSTEMS. THE MAIN HYPOTHESIS IS THAT SPATIAL HETEROGENEITY OF THE URBAN ECOSYSTEM, COUPLED WITH MULTIPLE ANTHROPOGENIC STRESSORS DERIVING FROM MANAGEMENT PRACTICES, WOULD EXERT A SELECTIVE PRESSURE ON THE STRUCTURAL AND FUNCTIONAL BIODIVERSITY THROUGH ENVIRONMENTAL FILTERING AT VERY SMALL SPATIAL SCALES. THE PROPOSED METHODOLOGY IS BASED ON THE STUDY OF MULTIPLE COMMUNITIES (PLANTS, MICROARTHROPODS AND MICROORGANISMS) AND MULTI-FUNCTIONAL TRAITS COUPLED WITH SEASONAL BLANKET SAMPLINGS, WITH THE AIM TO OBTAIN RELIABLE DATASETS WITH HIGH SIGNAL/NOISE RATIO. THE ULTIMATE GOAL IS TO HIGHLIGHT THE DETERMINISM BEHIND BIODIVERSITY VARIATIONS AT SMALL SPATIAL EXTENT THROUGH VARIOUS CASE STUDIES IN THE MEDITERRANEAN AREA IN A MECHANISTIC FASHION.