The association pattern of structural and biomass traits of capparis spinosa L. with topographic and soil factors

Abstract

Understanding the plant's functional traits is the first step for recognition of present patterns in plant vegetation, responding to environmental conditions and how they affect the environment. Capparis spinosa is one of the important medicinal, edible and marketable species which sparsely grows in large parts of Marl lands on semi-arid rangelands of East Azerbaijan province, Iran. Therefore, in addition to measuring plant traits (structural and biomass traits), ecological association of these traits with environmental factors were also studied in August 2016. For this purpose, vegetation cover studied through selecting four representative masses having different environmental properties within research grazing exclusion area and establishing sampling network inside the areas. So, for each mass, thirty 3m2 plots (1.5 × 2 m) with 30 m intervals from each other established along with three 300 m-long transect. A composite soil sample up to plant rooting depth was collected from each transect. Slope percent, aspect and elevation were recorded as topographical factors. Also, vegetation traits measured in 5 healthy plant stands in each mass. In order to study the association pattern of structural and biomass traits with environmental factors (soil and topography), according to calculated gradient length, the method of redundancy analysis (RDA) was used. Totally, on the spatial scale, the soil factors had a greater influence on structural and biomass traits than topographic factors. So that the percentage of clay, electrical conductivity, acidity, silt percentage and gypsum content had the greatest impact on biomass traits. Structural traits were also most affected by the percentage of clay, electrical conductivity, soil moisture content and amount of gypsum. By investigating the relationship between plant characteristics and environmental factors, the results of this research are applicable to preservation, rehabilitation and development of this species as a multi-purpose plant in pasture areas. Meanwhile, measured traits are the essential requirements for calculating the diversity of performance.