The aim of this theme was to characterise the structural and functional diversity of free-living edaphic nematode communities associated with Carpathian grasslands in order to assess soil nutrient resources, the complexity of the edaphic food web and the dominant pathway of organic matter decomposition. For this purpose, the structural and functional diversity of nematofauna was analysed in 25 Carapatine grasslands, most of which are located in protected natural areas of Community importance (Natura 2000 sites). The most diverse nematode communities were found in the Metaliferous Mountains, as opposed to the Rodna Mountains. Overall, the nematofauna of the Apuseni meadow meadows was the most diverse, while the grassland nematocenoses of the Eastern Carpathians were the least diverse. Fifty-four nematode species with restricted distribution in Carpathian ecosystems were identified.