The species diversity of cereal and root communities in the municipalities located in the strug river valley in Podkarpackie Voivodeship

The research on segetal flora and agricultural ecosystems has gained special importance in recent years, since they are an important element in biodiversity conservation. An evaluation of the status of the segetal flora was made on the basis of a study conducted in the period 1998–2002 in crop fields of four municipalities located in the Strug River valley in Podkarpackie Voivodeship. This research was carried out in root and cereal crops. Total species richness and the average number of species per relevé were determined in this study. In determining species diversity of the communities, the Shannon-Wiener diversity index (H’) was used. In cereal crops, the community Vicietum tetraspermae typicum was characterized by the greatest species richness (109 species), while Vicietum tetraspermae consolidetosum showed the lowest richness (57 species). In root crops, the association Oxalido-Chenopodietum polyspermi exhibited the greatest richness (78 species), whereas Galinsogo-Setarietum typicum the lowest richness (53 species). In the cereal communities, a total 149 of weed species were recorded, while in the root communities their total number was 97. The values of the Shannon-Wiener diversity index (H’) ranged from 3.10 to 2.42. The phytocoenoses Oxalido-Chenopodietum polyspermi, Vicietum tetraspermae typicum, and Vicietum tetraspermae, the variant with Vicia grandiflora, were characterized by the highest values of the Shannon-Wiener diversity index (H’), whereas the association Galinsogo-Setarietum typicum and the impoverished communities from the alliance Aperion spicae-venti showed the lowest values