Plant-associated nematode communities in West-palearctic coastal foredunes may relate to climate and sediment origins

Plant-associated nematode species are supposed to cause marram grass (Ammophila arenaria) decline in foredunes. But experiments with inoculated species populations have not proven any nematode effect on plant die out. Considering that nematode community patterns (ecological approach) would be more effective on plant growth than emblematic species (agronomical approach), a large survey in North (Belgium, France, The Netherlands, UK) and South (Portugal) European and in North African (Morocco) foredunes was conducted in order to analyse the diversity of the plant-associated nematode communities. It indicated that diversity (population levels, richness, diversity, evenness, trophic and colonizer/persister groups) does not differ between the communities sampled. But, the nematode community patterns are significantly impacted by climate and soil factors. Root-knot (Meloidogyne spp.) and lesion (Pratylenchus spp.) nematodes were more represented in Atlantic than in Mediterranean nematode communities, whereas cyst nematodes (Heterodera spp.) were more abundant in Northern than in Southern Atlantic nematode communities. Within the French nematode communities, the Atlantic communities strongly differ from the Mediterranean communities. It could be hypothesized that the sediment origin of the foredunes (e.g. Massif Central and Pyrenees for Atlantic sites vs Alps for Mediterranean sites) may be involved, because one Mediterranean site that showed an intermediate pattern is concerned by sediments from Massif Central origin. Knowledge about plant-associated nematode community structures in marram grass foredune ecosystems would help landscape managers for dune stabilization with plants.

• First paper about plant-parasitic nematode community patterns in coastal foredunes.
• Responses of community structures to West-paleartic climates.
• Effect (hypothesis) of soil sediments on patterns.
• Significant results to understand nematode species coexistence in natural ecosystems.