Distinguishing Desert Environments by Ecogeomorphic Thresholds

Document Type : علمی -پژوهشی

Abstract

According to the high diversity of vegetation, soil and bare rock patterns in the desert ecosystem and non-desert districts, distinguishing these areas is difficult. The approach used in this research introduced an ecogeomorphic view based on inverse recovery and erodibility potential to identify desert zones. The recovery/erodibility ratio can change the ecological resilience of ecosystem which shows resistance degree of system to environmental disturbances. The aim of this study was distinguishing desert environment based on eco-geomorphic boundries in Khorasan Razavi province as critical region to desertification process in Iran. In view of this four maps including lithology, vegetation cover, soil and isohyet were provided for analyzing the changes of recovery and erodibility ratio. The TM/ETM+ imagery data, geological map and soil map in scale 1:250'000 were used to prepare layers. An unsupervised classification was applied based on MODIS imagery data which shows eco-geomorphic dynamics along climatic/lithologicgradient.A zone as case study was selected where located in Lut and Sabzevar geological blocks. The climatic and topographic gradients were main reasons for choosing this case study in the KR province. Ecological and geomorphologic changes confirmed the erodibility - recovery oscillations in the study area. Results indicated two ecogeomorphic thresholds delineated based on characteristics of lithological, soil, and vegetation cover, rainfall fluctuations. The transition shows an ecogeomorphic transition between non-desert to semi-desert environments and a transition between semi-desert to desert region.

Keywords

References

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