Influence of edge effect on plant composition and distribution in oak forests (Case study: Cheharzebar forests-Kermanshah)

This research aimed at evaluating the influence of the edge effect caused by forest fragmentation on the composition and distribution of plant species in an oak forest of Kermanshah province. Three forest patches with similar slope and altitude located on the southern slopes were selected. Vegetation sampling in each patch was conducted at 0, 25, 50, 100 and 150 meter distances along three transects which were 200 m apart (N= 45). Cluster analysis and detrended correspondence analysis were applied to categorize the vegetation variation trend in the different patches. To detect the characteristic species in each category, Monte Carlo test were applied. The floristic results indicated 115 plant species within this area which belong to 91genera and 25 families. Three categories were recognized, including i) the forest edge samples group (0 and 25 m), ii) the intermediate samples group (50 m) and iii) the deep forest samples group (100 and 150 m). The characteristic species of the edge group were Alopecurus myosuroides, Alyssum menicoides, Euphorbia cheiradenia, Gundelia tournefortii, Lactuca serriola, Silene conoidea, Tragopogon longirostris, Trifolium repens, Verbascum pseudo-digitalis. The characteristic species of the intermediate group included Aegilops umbellulata, Bunium paucifolium, Erodium cicutarium, Eremopoa persica, Lens orientalis,Trigonella monantha , Vulpia myuros , whereas those of the deep forest group were Boissiera squarrosa, Callipeltis cucularia, Chardinia orientalis, Crupina crupinastrum, Pterocephalus plumosus, Scandix pecten-veneris, Stipa barbata.