Sardinian grasslands: from environmental, management and biotic factors interconnection to a regional thematic database

This doctoral thesis explores Mediterranean grasslands in Sardinia, Italy, focusing on environmental factors, land management, and species interactions. Grasslands support a high level of biodiversity and provide several ecosystem services. Moreover, they are historically and culturally significant, and precise data collection is essential for understanding and preserving them. The main goal is to increase the knowledge of these ecosystems by studying how they respond to environmental changes and human activities to aid in their conservation. The first part of the research analyses the intra and inter-annual variability of their floristic composition and investigates how they depend on rainfall. The study was conducted on a farm representative of Mediterranean silvopastoral systems in the central-western part of Sardinia, Italy. The study took place from 2018 to 2022, with surveys in both spring and winter, using the point quadrat method along eight permanent transects. Significant variations in plant composition between winter and spring seasons affect pasture quality and biodiversity. Rainfall affects different plant species differently. The second study underscores the importance of considering species interactions and land management for sustaining grasslands and conserving the ecosystem. A multispecies approach helps understand plant community diversity and prevent biodiversity loss due to changes in habitat. It examines how plant and ant communities respond to pasture abandonment, showing that ants can be effective indicators of biodiversity. This approach simplifies complex taxonomy and aids in the early detection of environmental changes and biodiversity loss in mountain habitats. The third study describes a georeferenced regional database created for Sardinia's grasslands named SaGRA. The database collects vegetation data from projects conducted between 2011 and 2021. Each survey is associated with environmental and management variables. The surveys were performed in 685 plots, mainly in central-western and north-eastern Sardinia. Despite some limitations, such as uneven survey site distribution, SaGRA represents a step forward in scientific research and natural resource management in Sardinia, facilitating broader-scale research. With these three studies, the doctoral thesis aims to contribute to understanding, managing, and preserving Mediterranean grasslands in Sardinia.