Identifying Ecological Vulnerability of Protected Complex of Touran via the Methods of Reciprocal Effects Matrix, AHP, and EA

Ecological vulnerability is a common term that can be used in different hierarchical levels (animate, population, community, ecosystem, and landscape). Ecological vulnerability evaluation has lots of applications in environmental sciences such as EIA, risk assessment and environmental monitoring. This represents the importance of the evaluation. This paper aimed at assessing ecological vulnerability of the protected area of Touran (in East of Iran) using a combination of three methods of overlay, i.e., reciprocal effects matrix, AHP, and EA. So far, a large number of researches have been published about these methods around the world and Iran, as well. Some works in Iran are “Degradation Model” and Jabbarian's work which has innovations in objectifying ecological vulnerability assessment with reciprocal effects matrix approach. We can also point to zonation of environmental vulnerable and sensitive areas in west of Fars Province with method of fuzzy logic approach and AHP. Different methods have been used around the world to assess ecological vulnerability. Some of these methods are FAHP and compound the methods of AHP and GIS and also Multiway Data Analysis (MDA) for detecting relations between indicators, Reciprocal of Fractal Dimension (SPCA) and compounding ecosystem sensitivity and landscape pattern. More diverse indices have been used in the field of ecological vulnerability, so far. Some of these indices are ecological Sensitivity (ES), Natural and Social Pressure (NSP), Ecological Recovery Capacity (ERC) and the others related with landscape such as Reciprocal of Fractal Dimension (FD), Isolation (FI) and Fragmentation (FN). In this paper, indices of Ecological Sensitivity are used because these data are available in Iran. Protected complex of Touran is in southeast of Shahroud City, southwest of Sabzevar City and in the north of great plain of Kavir in Semnan Province (from 55 to 57 E and from 34° 44' to 36° 22' latitude). For calculating ecological vulnerability, first of all the reciprocal effects m atrix must be prepared. In this method, a matrix of ecological factors in which if the points of an ecological factor effects on other factors they are given figure of one and otherwise figure of zero. In the next steps, the summation of rows and columns and the degree of importance of ecological factors is calculate based on following equation. The most effective factor in ecological vulnerability that obtained through reciprocal effects matrix and AHP method (Fig. 1) was erodibility of soil.This factor affects extremely other factors such as soil depth, water erosion and wind erosion. The weight of this factor in AHP was obtained about 0.371. The climatology and elevation factors are lower than the erodibility of soil. They are with preference degrees of 0.161 and 0.137, respectively. In the end of the list both layers of soil depth and vegetation density are affected by other factors, with preferences degree of 0.16. Finally, the map of ecological vulnerability was obtained by weighted overlay of the layers and also by applying scales of classes for each layer. It is remarkable that location of the areas in sensitive geological zones, zones of deep soils, arid and warm climate, and wind erosion zones is determinant in vulnerability degree of those areas. These layers are converted into raster format and then overlaid by their weights; finally the map of ecological vulnerability was obtained as a result raster layer. For better land management, the area was classified by natural breaks method (Fig. 2) into four classes of resistant, subsensitive, sensitive, and vulnerable. According to vulnerability map of the area, western parts are more vulnerable relative to other areas. Furthermore, most of the areas are placed in class of sensitive. Therefore, the protected area must be recognized in different managerial levels for more conservational acts.