engleski

Aquatic macrophytes as a trophic and spatial ˝playground˝ for free-living nematodes

In this investigation, we analyzed the spatial distribution patterns in free-living nematode associations in periphyton from the four aquatic macrophyte species. We sampled within monotypic macrophyte stands (Carex sp., Polygonum amphibium, Ceratophyllum demersum and Myriophyllum spicatum) at two localities, the Sakadaš Lake and the Čonakut Channel (Nature Park Kopački rit, Croatia). The measured environmental parameters within four macrophyte stands differ only in chlorophyll a concentration, highest recorded within M. spicatum stand. Sampled stands were all submersed during the period of investigation, despite the fact that Carex sp. belongs to emergent and P. amphibium to amphibian macrophyte. Sampled macrophyte species differ in leaves morphology, dissected and undissected leaves. The highest nematode abundances and the lowest species richness were recorded for M. spicatum. In total, 28 nematoda species were recorded. Chromadorina viridis, Chromadorina bioculata and Eutobrilus notus were recorded for all macrophyte species with highest abundance (families Tripylidae and Chromadoridae). The family Dorylaimidae was presented with the highest number of species but with low abundance. Week relationship between dry weight macrophyte biomass and species diversity were recorded. The dominant nematode functional group, based on feeding habits, was epistrate feeders for M. spicatum and chewers for C. demersum. At Carex sp. and P. amphibium there was almost an equal distribution of two functional groups, epistrate feeders and chewers. Positive significant correlation between C. bioculata and chlorophyll a concentration measured within macrophyte stands were recorded. Plant feeders were recorded with low abundances and only related to P. amphibium and Carex sp.

macrophyte stands; aquatic free-living nematodes; functional groups

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