Document Type : Research Paper
Author
Abstract
30% of lands earth are considered as arid ecosystems with around 44.7 mil km2. About 39% of the latter with an area of 17.4 mil km2 are considered as semi-arid regions. Around 90% of semi-arid area are located in 27 countries which has a 20% population of the world. About 86% of Iran area is considered as dry areas which greatly affect the various functions of human population. Delicate conditions of ecosystems and human invasion to natural resources in these areas has provided a national warning. Analysis of historical situation would provide a good stance to monitor the desertification condition in these areas. In this study we have tried to compare the historical situation with present condition and analyze the desertification trend. Our results showed that 76.7% of Khorasan province area are impacted by various desertification mechanisms. Our analysis revealed that desertification of vegetation cover together with water and wind erosion (first order process) with 44.7 percent of the area are the dominant factor. Water and wind erosion together with vegetation cover destruction in 24.3 percent of the area is the second order process and finally salinization is the third order process.. In terms of desertification order, 36.6% are under extreme desertification impact, very hard, medium, and delicate are with 14.4, 13.1 and 12.6% accoridingly.
Keywords
)