Plant-feeding nematodes in coastal sand dunes: occurrence, host specificity and effects on plant growth

Abstract

Coastal sand dunes have a well-established abiotic gradient from beach to land and a corresponding spatial gradient of plant species representing succession in time. Here, we relate the distribution of plant-feeding nematodes with dominant plant species in the field to host specialization and impacts on plant species under controlled greenhouse conditions. We assessed plant-feeding nematodes in soil and roots of six plant species that dominate the vegetation at successional positions along the gradient. In controlled conditions, we determined performance of all plant-feeding nematodes on each plant species and their effects on plant biomass. Specialist feeding type nematodes were confined to plant species in either foredunes or landward dunes. Generalist feeding type nematodes were found in highest numbers in the landward dunes. Most tested nematode species decreased root, but not shoot or rhizome biomass. Host plant suitability determined occurrence of some plant-feeding nematodes in dunes, but abiotic and biotic soil conditions may play a role as well. Generalist feeding type nematodes were able to reproduce on all plant species. Feeding specialists, which are more protected by plant roots, might prefer host plants in the foredunes for the same reason as their host plants: to escape from natural enemies.