Environmental Factors Affecting the Structural Trials and Biomass of Onobrychis aurea Bioss

Recognizing the environmental factors affecting plants structural trials and biomass is important to conserve plants as well as their ecosystem function, and services. Onobrychis aurea is a valuable forage that is distributed in the marl lands and is considered as an endangered plant species in Iran. In the present study, the ecological characteristics (plant traits) of this species has been investigated in detail.

For this purpose, structural traits and biomass of O. aurea were investigated in 12 ecological units with different topographical and soil conditions. Three soil samples were taken to 15cm depth, (0-15cm) in each ecological unit. The relationship between structural traits and species biomass with environmental factors was tested by redundancy analysis (RDA) method in 2016.

The results indicated that the soil characteristics including clay, lime and silt content play a more important role in the structural and biomass traits of O. aurea evidence show. Spatial and topographical factors, especially elevation and geographical aspects, had a smaller contribution in structural traits and species biomass in comparison with soil factors. Higher structural values were recorded in heavy textured alkaline soils. The slope percentages also have no significant effect on plant characteristics.

The present study indicated that the soil and topographic factors are very important for management of O. aurea. In general, it should also be emphasized that having good knowledge related to plant ecology as well as environmental condition could help managers to conserve and rehabilitate endangered plants.