بررسي تشابه بين پوشش گياهي سرپا و بانك بذر خاك در منطقه حفاظت شده گنو

Investigation on similarity between standing vegetation and soil seed bank in Genu Protected Area

The Genu Protected Area encompasses Kuh-e-Genu, a single and isolated mountain rising above the Persian Gulf coastal plain. The Genu Protected Area is located in Hormozgan province, 30 km north west of Bandar Abbas between latitudes (27° 18ʹ50"-27°29ʹ 16" N) and longitudes (55° 57ʹ30"-56° 18ʹ4"E), at about 70 to 2347m above sea level. It covers an area of about 43000 hectares. The species composition in the soil seed bank of the study area was assessed using the seedling emergence method compared with the standing vegetation. Data on species composition of the standing vegetation was acquired from the releves of phytosociological study area. The soil seed bank is important because of the impact of the seed reserve of the soil on current and future vegetation. The surface soil was collected at 10-cm intervals among the horizontal scale and was divided to a 0-5-cm deep upper layer and a 5-10- cm deep lower layer, from 135 plots of 20 associations. Soils were spread on sterile sand in a glasshouse and watered regularly. Emerging of the seedlings was recorded for more than one year. A total of 3934 seedlings belonging to 163 species germinated. Among the germinated species 47 were found to be absent in the standing vegetation. However correspondence between species number and composition of the seed banks and the standing vegetation was poor. In other words, the species in the soil seed bank were not representatives of the standing vegetation. The species composition in the seed bank was dominated by therophytes but trees and shrubs were rare. It is concluded that Phanerophytes and Chamaephytes are vulnerable to destruction. Meanwhile similarity indices of the standing vegetation and soil seed bank in different associations were 11- 43 percent. It seems that different factors may be responsible for low similarity index, i.e. differences in vegetation type regarding to life forms, list of floristics in different associations, site conditions and drought.