Factor Influencing Land Degradation Sensitivity and Desertification in A
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International Soil and Water Conservation Research 9 (2021) 217e228 Contents lists available at ScienceDirect International Soil and Water Conservation Research journal homepage: www.elsevier.com/locate/iswcr Original Research Article Factor influencing land degradation sensitivity and desertification in a drought prone watershed in Thailand Saowanee Wijitkosum Environmental Research Institute Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand article info abstract Article history: This study aimed to assess land degradation sensitivity of an area contributing to desertification risk in Received 11 June 2020 Lam Ta Kong Watershed using Environmental Sensitivity Area Index (ESAI). Five risk factors comprised Received in revised form climatic, soil, geographical, land utilization and vegetation, and water resources factors together with 2 October 2020 fifteen sub-factors were used to analyze the sensitivity to land degradation. The spatial analysis was Accepted 21 October 2020 calculated using Geographic Information System (GIS) and Remote Sensing (RS) techniques. The key Available online 27 October 2020 factors influencing land degradation risks in the watershed area were analyzed using the triangular fuzzy numbers (TFNs) method. The results showed that approximately 33% of Lam Ta Kong watershed was Keywords: fi Land degradation affected by a high deserti cation risk excluded the water bodies and around 24.64% of the area suffered Desertification from a moderate risk. This research pointed out that key factors causing land degradation and deserti- Critical factor fication in the watershed area were related to the soil factors, followed by climatic, geographical factors, Medalus water resources, and land utilization and vegetation, respectively. The results of this study can be used as Triangular fuzzy numbers a database for planning and implementing area-based mitigations and measures as well as for land use planning in the watershed area. © 2020 International Research and Training Center on Erosion and Sedimentation, China Water & Power Press. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction studies indicated that various parts of the world are at risk and vulnerable to degradation, drought, and desertification (Momirovic Land degradation and desertification are the most critical et al., 2019; Boudjemline & Semar, 2018; Taghipour-Javi et al., 2016; environmental issues in many parts of the world. The problems are Lal, 2012; Bouabid et al., 2010; Contador et al., 2009). Therefore, challenging at local, regional, and global scales (Kosmas et al., combating drought, land degradation and desertification has been 2014). Land degradation, drought, and desertification are closely an international duty since 1992 (UNCCD, 2005), and the impor- related phenomena and the problems are quite complicated tance of this issue continues. The United Nations stated Target 15.3 (Wijitkosum, 2020; Lal, 2012; UNSO, 1999). Persistent degradation as part of a sustainable development goal to end desertification and of dryland ecosystems caused by both climatic factors and human restore degraded lands by 2030. To achieve this goal, it is necessary activities, including inappropriate land use and land management, to analyze current problems, future environmental trends, and led to desertification (Lahlaoi et al., 2017; Wijitkosum, 2014; Xie vulnerability. Desertification, land degradation and drought are the et al., 2015). The impacts caused by climatic factors occur slowly, global issues that pose severe challenges to the sustainable devel- but those triggered by human activities accelerate rapidly and are opment of all countries. Vulnerability assessment is a process more severe (Wijitkosum, 2016; Elsayed, 2013; Ibanez et al., 2008; which monitors and assesses an area to prepare mitigations and Sepehr et al., 2007). prevent future problems caused by land degradation and deserti- Land degradation and desertification are no longer limited to fication (United Nations Office for Disaster Risk Reduction arid or semi-arid areas as previously defined by the United Nations [UNISDR], 2014). Land degradation risk assessment mainly focuses Convention to Combat Desertification (UNCCD) (United Nations on spatial analysis since the process involves several factors unique Convention to Combat Desertification [UNCCD], 2005). Several to particular areas. The Environmentally Sensitive Area Index (ESAI) was developed for identifying environmentally sensitive areas (ESAs) by the Mediterranean Desertification and Land Use research project E-mail address: [email protected]. https://doi.org/10.1016/j.iswcr.2020.10.005 2095-6339/© 2020 International Research and Training Center on Erosion and Sedimentation, China Water & Power Press. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). S. Wijitkosum International Soil and Water Conservation Research 9 (2021) 217e228 (Lahlaoi et al., 2017; Greco et al., 2005; Kosmas et al., 1999; Basso et al., 1999). Although the model was created and validated under the conditions of the Mediterranean area, the model was later adapted for other areas and showed good results (e.g. Bouabid et al., 2010; Taghipour-Javi et al., 2016; Wijitkosum, 2020a). The original ESAI approach (Kosmas et al., 1999) involves soil, vegetation, climate, and management indices. It is a widely used model for monitoring desertification sensitivity in many areas. Many studies conducted in Euro-Mediterranean countries were analyzed based on the ESAI model such as Sepehr et al. (2007) in Iran, Momirovic et al. (2019) in Serbia, Lahlaoi et al. (2017) and Bouabid et al. (2010) in Morocco. Nevertheless, the land degradation and desertification process of an area involve several factors; therefore, many scientists modified the traditional model by adjusting the indicators. Taghipour-Javi et al. (2016) incorporated irrigation water as a factor into the model while Honardoust et al. (2011) added soil erosion and waterlogging factors as indices for assessing deserti- fication sensitivity area in Iran. Zolfaghari et al. (2019), Wijitkosum (2016), and Wijitkosum (2014) assessed the risk of desertification without considering management factors. The adjustment of various factors was considered based on conditions of the areas and risk factors that can affect land degradation and desertification. In addition, many studies modified the model by adding many suit- able sub-indices for assessing desertification risk effectively. Most researchers focused on the analysis of areas at risk, while the analysis of critical factors is still scarce. However, the analysis on critical risk factors was crucial to the planning of effective mitiga- tions (Wijitkosum, 2016). Many multiple mathematical models to group factors or analyze critical factors that pose a risk of deserti- fication, land degradation, and drought were introduced such as hierarchical cluster analysis (Zolfaghari et al., 2019), Analytic Hi- erarchy Process (AHP) (Sa-Nguansilp et al., 2017), Fuzzy Analytic Hierarchy Process (FAHP) (Zhao et al., 2017). However, the most appropriate model for analyzing weight and data involving a large number of factors for solving environmental and disaster problems was FAHP (Wijitkosum & Sriburi, 2019; Hosseini-Moghari et al., 2017; Zhao et al., 2017). FAHP (Chang, 1996) was developed from the fuzzy set theory, it adopted the hierarchical model by taking into account layers of criteria and sub-criteria. This study was conducted in Lam Ta Kong watershed, an important economic area located in the north-eastern part of Fig. 1. Lam Ta kong watershed area. Thailand. The area continually suffers from droughts for an extended period of time, especially during a dry spell and low precipitation period. This study aimed to explore a new approach the Mekong River. Lam Ta Kong Reservoir, with a capacity of 314 for the assessment of vulnerability related to land degradation by million cubic meters (MCM), is the main source of water supporting incorporating the ESAI model together the FAHP approach with all activities in five districts in the downstream area, including triangular fuzzy numbers (TFNs) and Geographical Information agriculture, manufacturers, and more than 83 communities System techniques (GIS). The focus of this study was to assess the (Wijitkosum & Sriburi, 2008). The watershed covers six districts degradation sensitivity area and its critical desertification risks which is divided into two main parts: the upper watershed area factors in order to propose feasible mitigations and preventive situated above the reservoir and the lower watershed area below the solutions base on land use management to combat desertification. reservoir. The upper reservoir area covers one district called Pak Chong District while the lower area covers five districts as follows Si 2. Methodology Khiu, Sung Noen, Kham Thale So, Muang Nakhon Ratchasima and Chalearm Prakeate (Fig. 1). 2.1. Study area description The majority area of Lam Ta Kong watershed was at moderate risk of physical drought (Wijitkosum, 2018), and severe risk of Lam Ta Kong watershed (Fig. 1) is located in the latitude of agricultural drought (Sa-Nguansilp et al., 2017). Moreover, the 746129.500500-854329.500500 and longtitude of 1596615.963806-