Nematodes in a coastal dune succession: Indicators of soil properties?

Abstract

The nematode fauna of coastal sand dunes in the Slowinski National Park (Poland) were studied. Within the wet parts of dune hollows, vegetational succession starts from bare wet sand gradually colonized by grasses and mosses, and changes to plant communities dominated by sundew and heath. The aim of the study was to determine whether vegetation succession was accompanied by a parallel succession of the nematode fauna. Samples were taken from 12 subsequent stages of vegetational succession. The extracted nematodes were determined up to genus level after Bongers (1987). The percentage of nematodes of different feeding types (bacteriophagous, fungivorous, predators, plant-parasitic and omnivorous) was calculated for every site. Soil moisture (average water table and actual water content), the existence of an upper organic soil layer and pH seem to be the key environmental factors influencing nematode community structure. Multivariate analysis techniques were used to classify the nematode samples into four groups: A – the nematode community in sites at early succession stages without permanent colonization by plants. B – the nematode community in sites at stages with permanent plant cover (grasses and higher plants). C and D – the nematode communities in sites with a developing permanent and stable soil organic layer, but differing in water regime. Changes in the incidence of nematodes of different feeding types in relation to vegetational succession support this classification. Nematode community structure changed from a high percentage of predators to a dominance of bacterial feeders. Fungal feeding nematodes only occur in abundance in sites with a developed organic layer and higher moisture content (group D), and the nematode community may be a good indicator of the progress of ecological succession in the deflation hollows.