Key features of bacterial communities in Southern Europe soils vulnerable to desertification

Mediterranean soils are experiencing increasingly negative effects of climate change due to drought and extreme weather phenomena that negatively affect agriculture, already suffering social and economic constraints. The LIFE project DESERT-ADAPT - Preparing desertification areas for increased climate change - (http://www.desert-adapt.it/index.php/en/) focuses on agricultural adaptation measures aimed at reverting ongoing desertification trends, while improving the socioeconomic conditions of farmers. The soil microbiota is recognized as key player in both diversity and productivity of terrestrial ecosystems and it is mandatory to include its role in sustainable agronomic management. In order to improve our understanding of soil microbes and their contributions to ecosystem functioning, we analysed, by automated ribosomal intergenic spacer analysis (ARISA), the bacterial communities of 70 soil plots from ten farms of Portugal, Spain and Italy under strong desertification risk. The bacterial diversity has been related to soil physico-chemical features and current soil use. Principal Coordinates Analysis (PCO) of ARISA profiles showed that pH, total organic Carbon, and soil use exert the strongest influence on bacterial diversity and structure. The results of this investigation will be used as baseline for the evaluation of the effects of adaptation measures implemented by the LIFE project in the ten farms.