Study on Vegetation Changes of Natural Ranges in KhoyBilehvar Semi-Steppic Area of West Azarbaijan Province

Document Type : Research and Full Length Article


1 Research Instructor, Agriculture and Natural Resources Center of West Azarbaijan

2 Range Research Division Research Institute of Forest and Rangeland, Tehran

3 Expert of Agricultural and Natural Resources Center of West Azarbaijan Province


The study of the exclosure effects on the vegetation changes under
grazing and non-grazing conditions in the rangeland areas has particular
importance in the rangeland improvement and revivification projects. The
research was accomplished in semi-steppe KhoyBilehvar area, from 1999 to
2005. Vegetation cover was annually measured within fixed plots during transact.
The results showed that during nine years of research, on KhoyBilehvar
exclosure, the total canopy cover has increased inside the exclosure, and the
highest increase was observed in the perennial grasses (more than 3.5) and
perennial Forbs (more than 2.5). Outside the exclosure, the total vegetation cover
was almost constant and changes were less in vegetation cover types. Within the
exclosure, some desirable species appeared consisting almost 19% of vegetation
composition. Medium species proportion in the plant composition increased to
more than two times and undesirable species decreased by half. Whereas, outside
the exclosure, scarce desirable species and medium species of vegetation ratio
has increased a little. The vegetation average of annual species during the study
within exclosure is more than outside and the vegetation average of forbs inside
and outside the exclosure is more than annual grasses. Nine year research in
Bilehvar exclosure showed that the correlation between precipitation changes and
vegetation cover was significant in the most species.