Surface sealing, loss of vegetation in metropolitan areas, an example from Hamedan

Iran's urban centres are rapidly changed to large industrial cities. Unfortunately, the responsible authorities for this process hardly take care for natural biotopes that habours many endangered plants. These urban activities led to the destruction of many areas covered by an indigeneous vegetation and to the replacement by industrial sites or settlements. Exit of any plant elements from cities is due to gradual environmental change, mainly as a result of human impact. This results many natural biotops in cities being removed and their plant elements decreases or appears in different from. One example for this irreversible process is indicated by Orchis coriophora L. (Orchidaceae), which still recently grew in a small natural area in the vicinity of Hamedan Faculty of Agriculture. The site of this rare species is now destroyed by urban activities and the taxon extinct in the Hamedan area.