SMALL WOODLOTS OUTSIDE FOREST: MULTI-SCALE AND MULTI-TAXA ASSESSMENT FOR ENVIRONMENTAL PLANNING

Trees outside forest (i.e., scattered trees, small woodlots - SWOFs, trees lines) represent important multifunctional resources, providing different ecosystem services at both global and local scales. Nevertheless, more studies are needed to better understand their part in biodiversity conservation. This is particularly true for areas located in important biodiversity hotspots, such as those in the Mediterranean basin. The main aim of this thesis was to investigate the role of Mediterranean SWOFs for biodiversity conservation, along a gradient of land-use intensification by using a multi-scale and multi-taxa approach. The adoption of multiple approaches, combining data from cartography to field-research and statistical models, contributed to understand the effect of human-disturbance and environmental conditions on taxa diversity patterns, with several theoretical and applied implications for SWOF management. An exhaustive census of SWOF in three land-use matrices highlighted that these patches represent a non-negligible component of natural and human-impacted land-uses, supporting a good level of biodiversity in human-altered matrices also. An intensive field sampling was conducted for almost two years to collect data on vascular plants and six invertebrates: pseudoscorpions, spiders, but also darkling, rove and ground beetles, and ants. This research provides a remarkable contribution to the knowledge of floristic and faunistic species distribution at regional, but also at national level. For almost all taxonomic groups, the dominant matrices surrounding SWOFs exerted a stronger effect on species composition rather than on species richness; it was observed a general homogenization of taxonomical diversity patterns of multiple taxa across SWOFs surrounded by urban and agricultural matrices, but also on one key functional trait of two congeneric plant species (seed mass). The high number of key native plants, richness and abundance of almost all invertebrates found in each land-use matrix underlines the need to preserve these remaining patches to avoid that homogenization drives a generalized biodiversity loss. This study also showed how the highly complex and variable interplay of environmental drivers (spatial-topographic, bioclimatic and landscape-level variables) and biological interactions influenced the cross-taxonomic congruence. Results support the hypothesis that SWOFs represent an opportunity for natural conversion actions and consequent rewilding ecosystems, with potential benefits for biodiversity conservation. The knowledge provided is a baseline to comprehend the role of small woodlots outside forest and give useful indications for planning and management conservation efforts.