Species and Functional Diversity of the Legume Component in Yellow Bluestem Pastures (Type Bothriochloa ischaemum)

Abstract

The present study aims to research the species and functional diversity of legume species in phytocoenoses of the yellow bluestem, developing under the conditions of Central Northern Bulgaria. The work was conducted in 2021–2023 on a pasture that is representative of the ecological conditions of the region. According to the results, the studied pasture type is characterized by a high species diversity of legumes, which give it a good forage value. Clearly expressed complementarity was observed, as well as functional diversity of the established species in terms of phenological development, growth rate, productivity of fresh and dry biomass. A relative abundance was observed in the range of 20--50% for five perennial species in the following descending order: Astragalus onobrychis,

Dorycnium herbaceum, Onobrychis alba, Medicago falcate, Bituminaria bituminosa. The indices of functional divergence (FDs) that were calculated for the observed morphological and reproductive traits of the indicated dominant species were high. They fall in the range 0.55–0.83, with an average value for the observed grassland type of FDs=0.64. The results obtained can be linked to a stable condition and a very good forage and self-recovery potential of the yellow bluestem pastures under the conditions of Central Northern Bulgaria.