Desertification Susceptibility over Khorasan-Razavi Ecoregions base on Life Cycle Assessment (LCA)

In recent decades, mismanagement, human activities and climatic conditions has been showed a new view of Iran's ecosystems, which called desertification. Life cycle assessment (LCA) is a method to construct the environemental profile of production systems. That was developed by industrial instruments, but in recent years it applied by agricultural production process as well. Today, it is acknowledged that land use should be assessed by LCA, but there is still no consensus on the parameters for assessment. In order to assess such land use impact, it is first necessary to define the variables in the LCI. Once the inventory data is gathered, the LCI results have to be characterised in the impact assessment phase. The main framwork of LCA is based on the "from cradle to grave" where we are able for evaluating environmental impacts truely from start point to the end. In this way we can use the theory of LCA to assess desertification indicators and estimation of ecosystem resistance to this phenomenon. So In this research was applied an LCA approch for estimating ecosystem susceptibility to desertification.
This research concentrated on role of LCA to distinguish ecosystem susceptibility to desertification phenomenon. In this way, in the first the land units were considered Ecoregions, the region with similar ecological and climataic characterestics, and six ecoregions has been identified. Then based on Delphi methodology, six main factor were detemined including aridity, landuse, wind erosion, soil erodibility, salinity and vegetation density.To calculate aridity, FAO/UNEP aridity index (P/ETP) was used. The land use map was developed by ETM imagery data and distinguished six classes including; desert, bare lands, cultivated lands, settlements, rangelands and forest. A report of critical center of wind erosion prepared by KR organzation of Natural Resources and watershed management was pplied for wind erosion. Soil erodibility was calculated based on the Sepehr et al, 2014. Salinity and vegetation indices were calculated by spectural ratio of imagery data. To assess susceptibility degree a characterestic factor (CF) for each ecoregion has been calculated. One of the main contributions of this study is the establishment of desertification impact CFs for the ecoregion. The divisions between these areas are based on climatic and vegetative cover factors, both aspects having a major influence on soil desertification risk. So after calculating CF for each ecoregion total characterestic factor was developed by geometric mean of each CF. Ultimately the susceptibility degree to the desertification was evaluated and mapped.
The results indicated the high preference aridity and wind erosion at Khorasan Razavi province which is in relation to the climatic conditions and land use changes in recent years. The greatest desertification risk is found in the moderate arid desert ecoregion, with a CF of 2.21. The susceptible ecoregions mainly covered more than 70% of the KR areas. In this case the desertification impact of the activity should not be integrated in LCA studies. This can be used to identify those cases without desertification impact. The LCIADesertification value is also zero when CFi or any other variable is zero. A value of zero for CFi means that the activity being studied is in an ecoregion with no desertification risk. The LCIDesertification value of the activity being assessed is determined by the addition of the individual values given to each of the sex variables, according to a scale of values. This paper provides CFs for including desertification impact in LCA studies, and the variables suggested allow the comparison of the benefits and threats posed by different human activities.
In this research, an LCA methodology was developed for assessing ecosystem susceptibility to desertification phenomenon. Main biophysical variables including aridity, wind erosion, landuse, erodibility, salinity and vegetation density belonging to the driving force, state and pressure frameworks were selected. The desertification impact evaluation of any human activity in a LCA should include these common, basic four variables. the purpose of this research is investigating desertification susceptibility degree of ecoregions at Khorasan Razavi as vulnerable province to land degradation and desertification in Iran. In this study was applied Life Cycle Assessment (LCA) framework to assess susceptibility. In the first, an ecoregions map was provided by adjusted De-Marton climate index. Six main indicators including aridity, land use, wind erosion, soil erodibility, salinity, and vegetation cover were determined by Delphi methodology. The preference degree of each indicator was calculated using Entropy algorithm. Ultimately was estimated characterization factor (CF) for each ecoregion. The layer integrating was done using geometric mean and desertification susceptibility map was prepared. The results showed that ecoregion of moderate arid desert is most susceptible to desertification.