hierarchical structure

As desertification is growing rapidly, adopting appropriate managerial strategies could help reduce its extension and prevent its development and spread. Otherwise, the loss of resources such as time, energy, etc., would bring about destructive consequences for the efforts made to combat desertification. On the other hand, the process of land desertification results from the interactions between various factors that always operate under uncertain conditions, being strongly influenced by vague and implicit judgments. However, no comprehensive method has been introduced yet to offer operational and reliable solutions for evaluating the strategies used for combating desertification based on a systematic collective fuzzy approach. Therefore, this study sought to combine the fuzzy theory with multi-criteria decision-making methods to evaluate the strategies used in combating desertification, using the Fuzzy DEMATEL method.

The fuzzy DEMATEL technique is a comprehensive method for creating and analyzing a structural model made out of causal relationships between a variety of complex factors under uncertain conditions. Accordingly, after determining the prioritized criteria and strategies via the fuzzy Delphi method and creating a fuzzy mean pair-wise comparison matrix, the matrix was changed to the normalized initial direct-relation matrix  according to equation 1:xij=zijr=lijr,mijr,uijr  (1) Then the mass communication matrix was formed by Eq. 2 (Table 1), showing the relative effect of direct and indirect relationships in a system.T=limk→∞X+X2+…+XK(2) Table (1): Fuzzy Mass Communication Matrix Di     D1 t k1nk-1… t k12 t K11 Tij = D2    t k2nk-1… t k22 t k21 ׃ ׃ ׃ ׃ ׃ Dn t knknk-1… t knk2 t knk1 Rn… R2 R1 Ri tij=lij",mij",uij" In the fuzzy mass communication matrix, the sum line (Di) indicates the extent of that factor's influence on other system's factors and its corresponding sum column (Ri) suggests the intensity of the influence of other system's factors on that factor. Therefore, Di+Ri  determines the total mutual impact of the desired factor and other system's factors on each other, and Di-Ri  shows the extent of each factor's final effect (only the effect) on all other system's factors. Then, the Di+Ri  and Di-Ri  were de-fuzzed according to Eq.3 to facilitate the analysis of the findings. (3)   BNP=lij+uij-lij+mij-lij3  Finally, a causal diagram (cause and effect) including a Cartesian coordinate system was drawn, with its horizontal and vertical axes being graded based on Di+Ridef  and Di-Ridef  values, respectively. Di+Ridef is the total de-fuzzed cause and effect, and Di-Ridef is the extent of the de-fuzzed effect. Moreover, the position of each existing strategy was determined within the system according to a point whose coordinates were (A: Di+Ridef , Di-Ridef). In this system, the points above the horizontal line indicate the effect strategies and vice versa, and the points to the right of the vertical line suggest the cause strategies and vice versa (Fig. 1). Figure (1): The causal diagram and the display of strategies

According to the related literature, first, the matrix of the order of criteria's influence on each other, and the matrices of the order of strategies' influence on each other were created in terms of the goal and each criterion, respectively, finding that that the effective strategies differed based on each criterion. Therefore, to select final strategies and grade their impact, the matrix of the order of strategies' influence on each other was formed in terms of total criteria within the group. Table (2): The matrix of the order of influence of strategies on each other in terms of total criteria Di-Ridef Di+Ridef Di-Ri Di+Ri Di    Ri Alternatives -1.252 -0.098 -1.887, -0.956, -0.912 -0.480, -0.31, 0.496 -0.625, -0.633, -0.767 0.145, 0.323, 1.262 A23 1.646 0.903 1.110, 1.515, 2.313 0.406, 0.695, 1.607 0.776, 1.105, 1.942 -0.371, -0.410, -0.335 A18 -1.011 -0.444 -0.548, 1.058, -1.427 -0.075, -0.305, -0.954 -0.421, -0.681, -1.081 0.346, 0.376, 0.127 A33 -0.271 -0.078 -0.186, -0.264, -0.364 0.034, -0.123, -0.145 -0.121, -0.194, -0.209 0.155, 0.070, 0.064 A20 0.889 0.367 0.480, 0.763, 1.421 -0.019, 0.197, 0.922 0.324, 0.480, 1.078 -0.343, -0.283, -0.156 A31 Finally, the causal diagram (cause and effect) was drawn based on Table 2 (Fig. 2) to better interpret the results. Figure (2): The diagram of cause and effect (causal) strategies to combat desertification based on total criteria.

According to the study's results, "appropriateness and compatibility with the environment" (C7) with the intensity effect of Di-Ridef=0.874  were the most important criteria based on the Fuzzy DEMATEL perspective, followed by "Destruction of resources, and environmental and human damages" (C16), "Specialized human resources" (C6), "Scientific and technological tools" (C5), and "time”, with their effect intensity  Di-Ridef being 0.802 , -132 , -630, and -0.914, respectively, indicating the experts' concerns for the environmental issues and the existing challenges in terms of the destruction of the environment. Based on the above-mentioned criteria, "preventing inappropriate land-use change" (A18) with the intensity effect of Di+Ridef=0.903  is definitely the most effective strategy to achieve the goal. Moreover, in terms of increasing cause and decreasing effect, other strategies were found to be "Reduction in extracting water from groundwater resources"(A31), " Controlling livestock grazing "(A20), "Developing and restoring the vegetation" (A23), "Changing the irrigation pattern and implementing less water-consuming methods "(A33), whose intensity effect Di+Ridefwas 0.903 , -0.078, -0.098 , and -0.444, respectively . Therefore, it is suggested that the results of this study be considered in the plans devised to control and reduce the consequences of desertification and land restoration in the study area. In fact, the current study's findings enable the managers working in desert areas to use limited facilities and assets available to them to effectively control the desertification process, prevent the loss of national assets, and achieve better results.

Desertification is the process of ecological and biological reduction of land potential in a natural or unnatural way, mainly affecting arid regions. Moreover, it decreases land efficiency with increasing acceleration. Land resources and human populations exposed to desertification and land destruction are prone to various threats, including loss of land productivity, food insecurity, water scarcity, economic problems, social deprivation, and health risks. Therefore, the complex and important dimensions of this issue prompted the international community to state at the Rio Environment and Development Conference that one of the goals of sustainable development is to fight against desertification, and to stop and reverse land degradation.   Subsequently, the important role of appropriate and appropriate local measures in dealing with global threats, desertification, and land degradation was emphasized at the United Nations Convention to Combat Desertification (UNCCD). Therefore, considering the limited resources and inputs, the sensitivity of ecosystems in desert areas, increasing success in implementing control plans and reducing the effects of desertification and restoration of destroyed lands, today the evaluation of desertification alternatives is considered as a determining factor in executive projects. Thus, it is necessary to design optimal methods for controlling and reducing this process. Therefore, this case study which was carried out in the Ardekan-Khezrabad plain sought to systematically evaluate optimal alternatives via a group decision model.  

To analyze and present effective alternatives, this study used Delphi method within the framework of multi-criteria decision-making method so that it can consolidate group opinions and use a pairwise comparison questionnaire, followed by a qualitative identification of the most important and prioritized criteria and alternatives. Then the significance of the criteria was estimated via special vector method. Finally, Bernardochr('39')s decision-making method was applied to finalize the alternatives and prioritize them. In the framework of this model, a ranking/criterion matrix was formed for each strategy in order to influence the weight of criteria in the selection of alternatives. The weights of the criteria were multiplied in these matrices based on the relation (1), and an agreement line matrix was formed for each strategy.  (1)  Then, the consensus matrix of the total alternatives was created from the sum of the consecutive line matrices of each strategy. After the formation of the agreement matrix, the total number of times that each strategy ranked in position 1 to k was estimated in the form of a compression agreement matrix according to the relationship 2. (2)     Finally, after influencing the weights of the criteria in the alternatives in the form of a consensual consensus matrix and the formation of an allocation model (Equation 3) for each strategy, the models were solved and the final priority of the alternatives was determined, using Lingo software.    (3)

According to the research literature, the importance of criteria in the desertification process was estimated from a special vector method. The results showed that the criteria of "Proportionality and compatibility with environment" (C7) was at the highest level of importance with a coefficient significance of 0.33877, followed by  "Destruction of Resources and Environmental and Human Damages" (C16) with a coefficient significance of 0.3111, "Expert Human Resources" (C6) with a coefficient significance of 0.1571, " Scientific tools and technology available" (C5) with a coefficient significance of 0.1039, and "time" (C2) with a coefficient significance of 0.9090, respectively, indicating the attention of experts and specialists to environmental issues and challenges in the field of environmental degradation. In general, according to the results of the final prioritization of alternatives, the highest value of the objective functions was found to be 6.7. Therefore, "Prevention of unsuitable land-use changes" (A18), "Modification of groundwater harvesting" (A31), and "Vegetation cover development and reclamation" (A23) were selected as the most appropriate subsets of current alternatives.  

The results of the application of the final prioritization of alternatives based on Bernardochr('39')s method showed that this method was catheterized by flexibility, high efficiency, ease of use, the possibility of using software such as Lingo and EC, and evaluation of alternatives based on a set of effective quantitative and quantitative criteria in-group format. In addition to using multiple criteria for decision making, it considers resource constraints in implementing alternatives or projects, providing an opportunity for decision-makers in the field of natural resources to use the limited facilities and capital allocated to control the desertification process in the right and efficient ways for better results while preventing the waste of national capital.

Owing to the oncoming needs and increasing the population of Lake Urmia Watershed، providing equilibrium between water supply and demand seems quite challenging and the Lake cannot be successful in meeting its ecological demands in this critical condition. In this unfavorable situation، water resources must be managed through a sustainable context. With this knowledge in hand، a multi attributes framework was applied to investigate the preference of supply or conservation alternatives. Preference of sustainable development attributes was calculated in a pairwise hierarchical structure and instead of time-consuming conventional procedure، Absolute Measurement was used that compares qualitative scales instead of alternatives and can overcome the problem of rank reversal in pairwise comparison. Ranks of the Alternatives were evaluated by VIKOR method which can provide a set of compromise solutions instead of one solution. Due to sensitivity analysis performance، VIKOR was introduced as a robust model in ranking the water resources alternatives. With regards to the results of this two-stage hierarchical-compromising approach، dealing with Watershed crisis is depended on organized indigenous collaboration، water use optimization and protecting available natural resources. On the other hand، supplying water by structural development without sustainability consideration would not be effective.