Fire slightly decreases on the short-term the competitive effects of a thorny cushion shrub in a semi-arid mountain steppe

These dataset include vegetation data for all study species in 4 treatments.In
each of the four treatments (two fire conditions X two exposures), we randomly
selected 25 shrubs and 25 paired open plots (Arzani and Abedi, 2015). There
were 25 replicates of each treatment combination with approximately 8-9
replicates per block. All selected O. cornuta shrubs were precisely selected
after checking leaves and stems of alive, healthy shrubs in nonburned sites and
also relict basal stem of shrubs in burned sites. Onobrychis cornuta had
different % cover and sizes in the two exposures (17.3 ± 2.1 % cover and 2.24 ± 0.29 m2 size
in north exposure and 4.3 ±
0.5 % cover and 1.20 ± 0.16
m2 size in south exposure, n = 20 (with approximately 6-7 replicates
per block), plots 4 m*4 m, unpublished data). After measuring the shrub size, each
shrub individual was divided in edge and center positions. Three microhabitats
(hereafter plots) including edge, center and open were finally selected (total:
300 plots including 25 edge, 25 center and
25 open plots in each of the four treatments). We sampled a fixed
area in each of the three microhabitats. For the center and open plots, a
quadrat of 20 cm*20 cm was used, whereas for the edge plots two rectangles of
10 cm*20 cm were set up along the northern and southern edges of the cushions. Each
open plot was located at a very short distance (< 2 m) from its paired shrub
and in the same microtopographic position. In July 2015, two years after fire, we
recorded cover of all vascular species present in both edge and center parts of
the shrubs and in paired open areas. Vegetation sampling was recorded at a
season where most species were in the flowering stage for better taxonomic
identification. We only studied the short-term effect of fire because monitoring
effect of fire for longer time and several years after fire is complex for edge
and center microhabitats since they should be precisely located due to the
disappearance of the track of the fire.