Floristic diversity versus utilization value of selected semi-natural Central-European grassland communities: A study from Poland

[Display omitted] •The biodiversity of grassland communities significantly affects their forage value.•The pattern of H'-UVS relationships depends on the type of plant community.•It is difficult to achieve high biodiversity and high forage value at the same time. Floristic diversity in agricultural landscapes results primarily from the diversity of semi-natural grasslands. Due to economical reasons, farmers are interested in agricultural intensification, while semi-natural grasslands are associated with low productivity. Therefore, 10 semi-natural grassland plant communities that are widespread across Central Europe and have different habitat requirements were studied: 4 from the Phragmitetea class, 4 from Molinio-Arrhenatheretea, and 2 from Festuco-Brometea. The study answers the following: (1) What is their floristic diversity and utilization value? (2) Is there a significant relationship between the diversity of vascular plant species and the utilization value of the examined communities? (3) If yes, what is the character of this relationship? The highest floristic diversity was shown by the Festuco-Brometea communities: Adonido-Brachypodietum pinnati and com. Brachypodium pinnatum. The average utilization value of the analyzed semi-natural plant communities was poor or very poor, but it varied within the plant communities, and the percentage of the relevés of at least a good utilization value was high for some communities. For most of the analyzed communities, the linear and statistically significant relation of H’ index with utilization value score (UVS) was observed. H’ index was positively related with UVS for Phragmitetum australis, Caricetum gracilis, Caricetum ripariae, and Deschampsietum caespitosae. H’ index was negatively related with UVS for Phalaridetum arundinaceae, Alopecuretum pratensis, Lolio-Cynosuretum, and Adonido-Brachypodietum pinnati. The study showed that the relationship between floristic diversity and utilization value depends on the type of plant community.