The European Juniperus habitat in the Sardinian coastal dunes: Implication for conservation

In this study, we explore the influence of environmental and anthropogenic factors on the floristic variability of the "coastal dunes with Juniperus spp." European habitat (code 2250*) in Sardinia. Two datasets were created: the first by inputting phytosociological relevés available in literature plus our own samplings; the second by including, for each relevé, environmental, floristic, and human-related factors. Differences in Juniperus habitat composition and the influence of the explanatory variables were analyzed by multivariate analysis, while GLM were used to test the effect of human disturbance and sampling period on several habitat parameters (plant richness, cover of endemic and alien taxa). The floristic composition differed among sites, being significantly influenced by all the variables analyzed except coastal type. Composition was governed mainly by a latitudinal gradient, linked to a climatic gradient, which varied from North to South. In addition, the floristic richness was positively influenced by low and medium levels of human disturbance. Similarly, the plant richness and cover of endemic taxa was positively related to medium level of human disturbance, while the cover of alien taxa was positively related to recent sampling. The analysis of our own floristic data together with those recorded from 1976 is useful to monitor floristic changes over decades and gives a better understanding of the "coastal dunes with Juniperus spp." habitat to contribute to its conservation; therefore, management actions, such as eradication of alien taxa, should be implemented.