Investigating the effect of physiographic factors on plant diversity in wild pistachio forests in Fars province Case study, wild pistachio Research Forest

A biodiversity investigation was carried out in the wild pistachio research forest located in southwest of Fars Province between 52˚ 30́́ to 52˚ 40́́ longitude and 29˚ to 29˚ 15́ latitude in an areaof 9374 Ha area. 72 sampling transects fifty meters long were designated using systematic-random design. In each sampling plot a list of bush, shrub, and tree species and their abundance were recorded. The area was divided into 3 slope levels (level 1: >10%., level 2:10%-30%., and level 3: <30 %), 4 aspects levels (north, east, south, and west) and 3 altitudinal levels (level 1: >1,800 m., level 2: 1,800–2,000 m., and level 3: <2,000 m. a.s.l.) using ARC GIS softwear. Data were analyzed using different indices of heterogeneity, richness and evenness by PAST software and were compared in each of the abovedivisions. Gratest heterogeneity and richness indices were observed in area with slope greater than 30%. Results show that the area with 10-30 percent slope has the highest uniformity. Also, indices of heterogeneity and richness showed that north aspect has higher value than the other directions. Evenness indices indicate that the east direction has greater uniformity. Diversity indices among altitudinal levelrevealed that diversity,eveness and richness in altitudes greater than 2000 meter above see level  is more than other altitudinal levels. The results showed that the vegetation diversity of the region are affected by the physiographical condition.