The importance of robust systems for classifying biogeographical patterns has been emphasized for its usefulness in designing conservation strategies. For such purposes, the distribution patterns of the endemic flora have often been used. Several studies have identified phytogeographical units within Sardinia (western Mediterranean); however, the main part of the island remains unstudied. Thus, the aim of this study is to lay out a comprehensive biogeographical scheme for Sardinia based on endemic vascular plant distributions, together with geological and geomorphological units. We georeferenced, in a 1-km² grid cell, the presence of 290 vascular endemic taxa from the literature, herbarium specimens and field investigators’ research. Sardinia was subdivided into 31 homogeneous units through the integration of geological and geomorphological maps and, subsequently, a presence–absence matrix of endemic taxa in each unit was built. Hierarchical cluster analysis was performed to define two levels of biogeographical units (i.e. sectors and subsectors). For each unit the exclusive and differential endemic taxa were identified. For sectors, indicator species were explored by the Indicator Value (Ind Val) analysis and relationships were analysed by quantitative interaction web. A total of six sectors and 22 subsectors were identified. The highest endemic plant richness was found in the Campidanese-Turritano, Sulcitano-Iglesiente and Supramontano sectors, and in the Gennargenteo, Barbaricino, Iglesiente and Sulcitano subsectors. All sectors were characterized by the presence of exclusive, differential and indicator taxa. The interaction analysis showed the highest uniqueness in endemic flora in the Supramontano and Sulcitano-Iglesiente sectors, which hosted a high number of exclusive endemic species. Mostly mountainous sectors/subsectors had higher endemic-species richness compared with lowland ones. The study showed the relevance of geology and geomorphology, together with accurate data on endemic distribution, to define consistent phytogeographical units. Furthermore, the biogeographical scheme presented here helps to define area-based conservation strategies in Sardinia.

Due to the impelling urgency of plant conservation and the increasing availability of high resolution spatially interpolated (e.g. climate variables) and categorical data (e.g. land cover and vegetation type), many recent studies have examined relationships among plant species distributions and a diversified set of explanatory factors; nevertheless, global and regional patterns of endemic plant richness remain in many cases unexplained. One such pattern is the 294 endemic vascular plant taxa recorded on a 1 km resolution grid on the environmentally heterogeneous island of Sardinia. Sixteen predictors, including topographic, geological, climatic and anthropogenic factors, were used to model local (number of taxa inside each 1 km grid cell) Endemic Vascular Plant Richness (EVPR). Generalized Linear Models were used to evaluate how each factor affected the distribution of local EVPR. Significant relationships with local EVPR and topographic, geological, climatic and anthropogenic factors were found. In particular, elevation explained the larger fraction of variation in endemic richness but other environmental factors (e.g. precipitation seasonality and slope) and human-related factors (e.g. the Human Influence Index (HII) and the proportion of anthropogenic land uses) were, respectively, positively and negatively correlated with local EVPR. Regional EVPR (number of endemic taxa inside each 100 m elevation interval) was also measured to compare local and regional EVPR patterns along the elevation gradient. In contrast to local, regional EVPR tended to decrease with altitude partly due to the decreasing area covered along altitude. The contrasting results between local and regional patterns suggest that local richness increases as a result of increased interspecific aggregation along altitude, whereas regional richness may depend on the interaction between area and altitude. This suggests that the shape and magnitude of the species-area relationship might vary with elevation. This work provides—for the first time in Sardinia—a comprehensive analysis of the influence of environmental factors on the pattern of EVPR in the entire territory, from sea level to the highest peaks. Elevation, as well as other environmental and human-related variables, were confirmed to be influencing factors. In addition, variations of EVPR patterns at regional-to-local spatial scales inspire next investigations on the possible interaction between elevation and area in explaining patterns of plant species richness.

Rock climbing is among the outdoor activities that have undergone the highest growth since the second half of the 20th century. As a result, cliff habitats, historically one of the least disturbed by human colonization worldwide, are facing more intense human pressure than ever before. However, there is little data on the impact of this activity in plant-communities, and such information is indispensable for adequate manager decision-making. The goal of this study was to determine the impact of rock climbing on plant communities in terms of cover, richness, and composition in relation to climbing intensity on typical Mediterranean limestone cliffs. Three rock-climbing sites were selected in the Baetic range (SE Spain), corresponding to qualitative categories of climbing frequentation: i)“low” (low frequentation with intermittent climbing), ii)“medium” (high frequentation without overcrowding), and iii) “high” (high frequentation with overcrowding). Within each site, we selected climbing routes and adjacent areas free of climbing, then we carried out a photoplot-based sampling by rappelling. We analysed the images to calculate: richness, species cover, and total cover. This study shows that rock climbing negatively affected the cliff plant community at all three study sites. A significant decrease in plant cover, species richness and a shift in the community composition were recorded for climbed areas, the cover being the variable most sensitive to rock climbing. Impact observed proved to be related to the frequentation level. Low-frequentation sites, with usually more specialized climbers, underwent relatively mild damages, whereas at high frequentation sites the impact was severe and the conservation of the species, especially rare ones, became jeopardized. Our study is the first one available to investigate climbing impact on plant communities in Mediterranean areas, but more research on the impact of rock climbing is needed to assess the regulation of this activity. Regarding management guidelines, we propose a management guideline protocol to evaluate climbing routes and design: i) “Sites free of climbing”, ii) “Strictly regulated climbing routes”, iii) “Mildly regulated climbing routes”, or iv) “Free climbing routes”.