Payame Noor University, Aran and Bidgol, Iran
Abstract: (10886 Views)
Agricultural and industrial activities cause emission of greenhouse gas to atmosphere, leading to increase of temperature of the atmosphere. Global warming changes temporal and spatial pattern of precipitation and temperature followed by change in bioclimatic areas. Ecosystems and biomes are affected by climate change as well. One of the most challenging questions regarding the global change concerns the impact that changing climate, loss of species and modification of landscapes will have on ecosystem function. Ecosystems contain the earth's reservoir of genetic and species diversity and provide services to individuals and societies through providing food, fiber, medicines and energy; processing and storing of carbon and nutrients; control ling of hydrological cycle, regulating water runoff; soil degradation; and services related to tourism.
These systems and functions are sensitive to the rate and extent of changes in climate. Rate of sensitivity and instability of ecosystems depend on composition and geographical characteristics.
In this research, we assessed the rate of sensitivity of Iran bioclimatic regions by using holdridge life zone model and hypothetical scenario. Thus, climatic data were used in 142 stations of Iran. Holdridge model was used to predict the changes in biomes distribution that likely occur under global warming. Classified bioclimatic according to the average of total annual precipitation and biotemperature that is defined as the average over the year of daily, weekly or monthly temperature, and is given the value 0 if the temperature is less than or equal to 0 or much than 30ºC.
Based on the results of this research and under the present climatic condition, all the stations are divided into 13 bioclimatic classes. Cold temperate region
has the highest change in global warming condition. Steppe and forest ecosystems have much sensivities in new condition (drier and warmer conditions).Desert types have little change in warmer and drier conditions.
Received: 2006/01/10 | Accepted: 2007/11/10 | Published: 2009/12/22