Title : A ecological approximation for the study of Arbuscular mycorrhizal fungi (AMF) sporulation in mediterranean sand dunes
Abstract:
The Arbuscular mycorrhizal fungi (AMF) belong to the phylum Glomeromycota. These fungi form an important symbiotic association with most plant species, in such a way that the plant receives inorganic nutrients from the fungus and the fungus obtains sugars from the plant. This interaction is very important for ecosystems with low nutrients availability, as it is the case of the sand dunes on the Mediterranean Coast. The main goal of our study was to determine AMF distribution and the optimal conditions for their sporulation. To this end, samples of the rizosphere of 4 structuring plants (Elymus farctus (Viv.) Runermark ex Melderis, Ammophila arenaria (L.) Link, Echinophora spinosa L. and Otanthus maritimus (L.) Hoffmanns. & Link) were collected in 2 sand dunes habitats (2110 and 2120, according the directive 92/43/CEE) as well as in their ecotone. Samplings were taken in 6 geographical locations along the coast and in each season for two years (2014-2015; 2015-2016). The mentioned habitats are characterized by a high soil mobility, low vegetable coverage and exposition to sea flood; all these environmental factors decreasing intensity from the habitat 2110 up to 2120. The preliminary statistical analysis using presence/absence data showed that the probability of finding AMF spores differed according to locality, habitat (lower probability at the habitat closest to the sea), and sampling season (higher sporulation in spring). However, no significant effects of plant species were found on the probability of finding AMF spores. Focusing on AMF species composition, Redundancy Analysis showed a significant ordination model, with the forward selection of particular localities, plant species, habitats and sampling seasons, which notably affected which AMF taxon was found in each sample. Further analysis of soil composition would help understanding if the effects of the studied categorical variables could be related to particular differences in soil traits such as humidity or nutrient availability