Floristic and habitat diversity of the dunes in the Narew River Valley

Abstract The aim of the research presented here was to determine and compare the habitat conditions of the two adjacent dune areas in the Narew River Valley. For the comparative studies we used the ecological indicator value method and the index of forest soil trophism (ITGL), both of which revealed differences between the investigated habitats. Values of ITGL indicate that in the case of the Uroczysko Serwańce dune, which is covered by a mixed coniferous forest (Serratulo-Piceetum), the habitat is oligotrophic, while the habitat on the Ławki Małe dune is dominated by a not yet fully developed Tilio-Carpinetum plant community which displays a mesotrophic character. Similar differences were observed using ecological indicator values. Soil indices calculated for the oak-hornbeam stand on the Ławki Małe dune indicate the presence of fresh, mesotrophic, humus-mineral soils made of sandy loam or silt substrate with a near-neutral pH. From these results we can deduce that climatic conditions, affected by peatlands, have a greater impact on the development of vegetation on inpeatland dunes than relatively poor soils.