The Effect of Physiographic Factors on Plant Species Diversity in Forest Gaps (Case study: Lalis forest, Chalous)

Variation in vegetation of forest gaps predominant by several factors. Unerring، the role of physiographic factors within gaps biodiversity process is very considerable. Hence، the relation of vegetation with physiographic positions was investigated within 59 forest gaps in Fagus forests of Lalis located in Chalous. Elevation range classified in three classes (1100-1200، 1200-1300، and 1300-1400) and slope in five classes (%0-20، %20-40، %40-60، %60-80، %80-100)، also. Aspects quantified by Azimuth، and plant species abundance annotated within gaps. Determination of relation between biodiversity indices and physiographic factors were accomplished by correlation coefficients. Results showed that، differences in mean quantities of biodiversity were significant for increasing of elevation. In survey of slope classes، differences in mean quantities of Simpson، Margalef and Peet indices a strong negatively correlation for the increase of slope، but other indices lacked significant correlation. Also in survey of aspects with differences in mean quantities of Shannon-Wiener، Menhinick، Peet and Camargo indices were significant correlation، and totality northern aspects devoted in most of biodiversity indices quantities.