Biology and conservation status of Juniperus macrocarpa Sm. in Sardinia

摘要: The present Ph.D. thesis aimed to provide a better understanding of Juniperus macrocarpa and the habitat that it characterizes (Juniperus spp. habitat; European priority habitat) in Sardinian coastal dunes, as well achieve results useful support situ ex conservation actions. In particular, specific aims were: (1) analyse morphological variation seeds Mediterranean taxa (at inter- intraspecific level) morphometric differences J. collected different populations, seasons sources; (2) evaluate effect collecting season, source, laboratory pre-treatments temperatures on seed viability germination macrocarpa; (3) investigate factors affecting seedling emergence, survival growth species; (4) explore floristic variability Sardinia relation geographic, climatic human variables, potential disturbance sampling period key plant parameters; finally (5) assess status this Sardinia. In first chapter, statistical classifier for based parameters analysed by image analysis techniques, was tested at interspecific, levels. Analysed came from galbules regions Basin 2010 four two plants soil. Two taxonomic treatments genus (Flora Europaea Plant List) were compared inter-population, seasonal source morphology analysed. High percentages correct identification reached both level comparison among oxycedrus, communis phoenicea complexes. Moreover, discriminated spring than those autumn, but seemed not be able discriminate soil, nor ones populations same geographical region. In subsequent phenology investigated. For purpose, ripe localities seasons, collected. order verify presence physiological dormancy, warm (W) cold stratification (C), combinations them (W+C C+W), no pre-treatment (control) applied. After pre-treatments, incubated range constant (10–25°C) alternating (25⁄10°C) temperatures. Seed low (ca. 40%) (plant or soil) had significant it, varied significantly according showing lower autumn spring. 10%), control W most effective stimulating germination, while C negatively affected germination. best 15 20°C showed higher 11%) 7%). Seeds are dormant study suggested secondary dormancy induced stratification. all along dispersal season (from spring) illustrated, potentiality taxon create soil bank. In third seedlings, study, permanent plots placed periodically monitored. Within them, besides (emergence, growth), several biotic abiotic variables (solar radiation, tree cover, herbaceous plus scrub distance closer female, number event herbivore trace) measured. Linear mixed-effects models used test relative importance groups explanatory parameters. A total 536 seedlings marked, which emerged winter. "microclimate" fit model explaining highlighting positive between cover. Survival very died months reaching highest mortality rate summer. values herbivory solar irradiation increased risk. Our confirmed is slow growing species, size class. depended suitable microhabitats, particular positively related hours sunlight, and herbaceous Despite these relevant results, long-term studies needed identify issues life cycle (e.g. fitness, recruitment). In last explored. data sets created: one inputting phytosociological releves available literature our own releves; second including each releve categorical variables. composition differed sites mainly ruled latitudinal gradient linked gradient. Regarding evaluation quality, richness influenced medium disturbance; endemic cover disturbance, alien recent samplings. following IUCN protocol we also assessed. Preliminary should considered endangered (EN) regional level. In conclusion, gave new findings recovery planning species under study. Specifically, found collection. We suggest: planting sowing, with being preferable sowing; shielding radiation canopy; application techniques such organic blanket when sowing selected option. addition, improve habitat, advise management measures eradication taxa, interventions reduce impact dune systems.