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Combatting desertification using a multidisciplinary approach
Catena 128 (2015) 211–213
Contents lists available at ScienceDirect
Catena journal homepage: www.elsevier.com/locate/catena
Preface
Combatting desertification using a multidisciplinary approach
1. Introduction Internationally, recognition and awareness is growing that soil is one of the most important and, at the same time, most vulnerable resources to mankind. Soil is not only crucial for food production, but also an important regulating factor in mitigation of climate change through e.g. storage of carbon (Lal et al., 2004) or retention of water (Kato et al., 2011). The loss of this valuable resource through various processes is especially prominent in areas where soil is already under pressure from harsh natural conditions; the arid regions in the world. Drylands, cover almost 40% of the world land mass. The United Nations Committee for Combatting Desertification (UNCCD) estimates that total land degradation affects 1.9 billion hectares of land worldwide, while 24 billion tons of fertile soil actually disappears on a yearly basis (UNCCD, 2012). 2. Finding solutions for desertification using an integrated approach — the DESIRE project With more than one billion people at risk, combating desertification is essential to ensuring long-term productivity of inhabited drylands. Desertification is generally defined as land degradation in arid, semiarid and dry sub-humid areas resulting from various factors, including climatic variations and human activities. In this definition, land degradation refers to the loss of biological or economic productivity of soil and local water resources, land surface and vegetation including crops (UNEP, 1994; UNEP, 1997). Promising sustainable land management (SLM) strategies exist — but information about them is often not effectively shared. Consequently they remain underutilized, and degradation in drylands continues. The DESIRE project (DESIRE — “Desertification mitigation and remediation of land — a global approach for local solutions”) strove to find solutions for these pressing issues by developing tailor-fit solutions specific to the 18 case study sites where the ‘DESIRE approach’ was applied, involving local stakeholders in the entire process from assessment to local implementation. Project activities were successfully implemented between 2007 and 2012 and results are being applied in multiple ways, as is shown in a number of research papers presented here. The dynamic and multi-dimensional nature of land degradation makes accurate assessment of the problems and development of appropriate responses a difficult challenge. Existing assessment methods rarely integrate various different components of land degradation, and local communities are seldom able to improve the sustainability of their land management without proper guidance and related incentives. Although western science has traditionally played a key role in determining the extent of land degradation and exploring its causes
http://dx.doi.org/10.1016/j.catena.2014.10.001 0341-8162/© 2014 Published by Elsevier B.V.
and drivers, integrated approaches for dealing with degradation itself have until recently not been available. 3. Involve the community — key for success The UNCCD highlights the importance of both scientific and community based approaches, and promotes integrated action to combat desertification. Actions must emphasize multi-stakeholder participation to enable local people and NGOs to reverse land degradation through self-help, in an environment enabled by governments and fully integrated into national policies. What is needed is an approach that combines scientific rigour and accuracy with relevance and sensitivity to local perspectives and local context. Conservationists, land managers and local communities need to work together towards shared, selfdefined goals. The basis of the DESIRE project was developing a universally applicable approach for identifying, prioritizing, testing, evaluating and implementing appropriate SLM technologies and tools to inform decision makers. The DESIRE approach, consisting of five fundamental steps, can be applied by agricultural advisors, government institutions, or any project that aims to combat land degradation, locally or regionally. Details about this method can be found on the DESIRE project website (DESIRE, 2013) and in the book ‘Desire for Greener Land’ (Schwilch et al., 2012), that describes the project in detail. 4. Project objectives The first objective of DESIRE was to look at degradation and desertification processes in an integrated way, in order to review the cause and effect links and give conservation measures a sound scientific basis. The second objective was to improve the definition of suitable indicators for both qualitative and quantitative evaluation of the land degradation and desertification status in the selected study regions, while the third objective of DESIRE was to assess and develop promising conservation measures using a participatory approach with stakeholder groups. This ensured that the measures were practical, acceptable and affordable for the people who had to implement them, and still kept evaluation of their effectiveness solidly science based. The fourth objective was to evaluate mitigation and remediation measures on a larger than local scale, using a set of spatial models and geo-information tools that permit the evaluation of both on-site and off-site effects at various scales. The fifth objective of DESIRE was to disseminate the results, guidance and decision support tools in suitable formats for all relevant stakeholders. This special section contains a number of papers covering results of the scientific research that are the product of the project objectives
212
Preface
mentioned above. The papers presented here focus on biophysical research, while a special issue in Land Degradation and Development (Fleskens et al., 2014) focuses on some of the unique approaches used in the DESIRE project, and the special section in Environmental Management (Hessel et al., 2014) highlights the perspectives of multiple stakeholder communities living in dryland areas. A concise overview of the research papers presented in this special section is given below. 5. Biophysical research — the basis for reaching the project goals Shakesby et al. (2013) report on the impacts of prescribed fire on soil loss and soil quality in the Portuguese Vale Torto catchment, the study area selected for the DESIRE project. Portugal has been a victim of frequent forest wildfires during the last 50 years. The semi-arid climate found in Portugal makes burned hill slopes vulnerable to erosion and causes, besides loss of soil, loss of organic matter and nutrients. One method to reduce the risk of fires and control the character of fire itself, is to reduce the amount of available (ground) fuel using prescribed or controlled fires. The disadvantage of this method is, again, its impact on soil quality and risk of soil degradation after the vegetation has disappeared. After a fire, the (almost) bare soils are being exposed to rainfall events that can cause severe surface runoff, taking along soil, organic matter and nutrients. The paper of Shakesby et al. describes the loss of soil organic matter and some nutrients after a forest fire, and directly connects to the first objective of the DESIRE project. For the prescribed fire a hill slope was selected and various parameters before and after the fire were analysed. The biggest decline in organic matter and nutrients occurred in the top 2 cm of the slope, but this was only 2.9%. However, the authors conclude that the analysis has taken place a short time after the fire and to get a better picture, the area should be monitored for a longer period. Rajesh et al. (2014) investigate and quantify temporal changes in gully erosion areas using object oriented analysis. The results of this PhD study enable the use of satellite observations to estimate the speed at which erosion gullies develop over time. This, in turn, delivers valuable information about the effectiveness of land management options to reduce land degradation, and is therefore a useful tool for monitoring and evaluating measures quickly and at a larger scale. The study includes improved procedures for mapping gully features from Ikonos-2 and GeoEye-1 data (optical imaging) by using contrast and edge filter information and thereby improving procedures for recognizing potential gully systems. One important new feature was the use of erosion process knowledge, improving the quality of the analysis further. The complex gully systems were better identified semi-automatically than was possible by manual digitization; in particular the finer edges of the gully systems, which in turn led to better quantification of changes in the gully systems. The rule-set for analysing satellite data developed in this study, promises to be applicable in other areas with minor adaptations. This paper does not directly contribute to one of the project objectives, but improves the accuracy of assessing gully erosion development in time. Ferreira et al. (2015–this issue) present a review of methods for remediating potential damage to soils in burnt Mediterranean areas. A big problem is that soils being affected by forest fires are most vulnerable to soil erosion directly after a fire has occurred, thereby leaving little time for taking effective remediation measures. The most effective measures for preventing soil loss through erosion were those that enhance infiltration of water, thereby reducing surface runoff. The authors not only describe measures that can be taken directly after a forest fire, but also preventative strategies and (planning) techniques that limit the post-fire effects or enhance or simplify restoration. As in the paper of Shakesby described earlier, prescribed fires are discussed as are preventive afforestation techniques. Also the locations where the restoration or prevention measures are to be deployed proved to be important. At the end of the paper, a table is presented summarizing
the various techniques together with references, implementation costs, manpower needed for implementation and different ecological properties. This paper directly ties into the third objective of the project (developing promising conservation measures) by giving a thorough overview of available measures, their advantages and disadvantages, thereby offering a valuable checklist for stakeholders in forest fire prone areas in the Mediterranean. Kosmas et al. (2014) present a paper about using an indicator system for analysing the phenomenon of land abandonment in 10 DESIRE study sites in the Mediterranean region, Eastern Europe, Latin America, Africa and Asia. This paper thereby fulfils the second objective of the DESIRE project by improving the definition of suitable indicators for both qualitative and quantitative evaluation of the land degradation and desertification status in drylands. Land abandonment is a phenomenon that often materializes from socio-economic motives but as a result can also have serious environmental implications. Land abandonment is defined as a change in land use that moves from a traditional or recent pattern to another, less intensive pattern. The authors in this study focus on the regional scale drivers using drivers, as promoted by the UNCCD, for simplifying reality to make complex processes quantifiable. From a candidate set of 48 biophysical and socioeconomic indicators they constructed an indicator system by using available classification systems, ranking based on existing research data and expert opinion. Using this indicator system, a Pairwise Spearman rank correlation analysis between land abandonment and selected biophysical and socioeconomic drivers was performed, thereby finding a significant correlation between land abandonment and eight (mainly socioeconomic) variables; land fragmentation, rainfall seasonality, population density, runoff water storage, elderly index and farm size were the indicators mostly associated to land abandonment. The presented methodology proves to be a valuable tool for identifying key indicators that affect land abandonment at different spatial scales, in specific dryland areas under local conditions. Gkiougkis et al. (2014) analyse the process of soil salinization, the prominent cause of land degradation in the Nestos river delta in the north-east of Greece. They present a hydrological, hydrogeological and geological analysis of the DESIRE study area that includes field and laboratory data from 2007, 2008 and 2009. The main reason for the salinization of the area is the presence and use of saline groundwater that has intruded from the nearby coastline, together with limited natural drainage of the soils. The authors present a number of traditional solutions for the salinization problem; attaining a better control of the groundwater table, improving the soil drainage potentials and the use of calcium for leaching out the exchangeable sodium are the most promising. Along with some more innovative, promising, measures presented are irrigation with treated waste water, automated irrigation control and use of crops resistant to high salt concentrations. The lack of sufficient amounts of freshwater remains the largest problem. This paper fulfils objective number four; evaluating mitigation and remediation measures at a larger scale. In the final paper of this special section, De Pina Tavares et al. (2015– this issue) is also connected to the fourth project objective as mentioned above, and presents a study about the sensitivity to desertification in one of the DESIRE study areas, the Ribeira Seca watershed on Cape Verde. This area is sensitive to land degradation due to the steep terrain and arid climate. The results are presented as desertification sensitivity maps generated using the MEDALUS model and six quality indices derived from climate, soil, vegetation, land management, erosion and a number of social parameters. The study presents a valuable tool for pinpointing the most vulnerable locations and areas that could benefit most from preventative measures against land degradation. The papers presented in this special section provide insight into the broad field of research that is involved in trying to tackle the complex problems of land degradation and desertification. This section in CATENA mainly accentuates the biophysical research aspect of the DESIRE project, opposed to the social and economic aspects of the
Preface
project. This wide scope of subjects in the total collection of presented papers is the result of the integrated approach that was chosen for this project. Throughout the papers, the value added by the integration of different disciplines becomes clear; this is even more apparent in the main result of the DESIRE project, the ‘DESIRE approach’, as presented in the DESIRE book. The DESIRE project is a clear example of the empowerment and productivity that can result from scientific research that uses an integrated, multi-disciplinary approach. It is the hope of all participants in the DESIRE project that these results will inspire more research using the DESIRE approach as a tool — where, in the end, the results are greater than the sum of the parts. References DESIRE, 2013. The DESIRE Project: Desertification Mitigation and Remediation of Land — A Global Approach for Local Solutions. Project website. http://www.desire-project.eu. Ferreira, A.J.D., Alegre, S.P., Coelho, C.O.A., Shakesby, R.A., Páscoa, F.M., Ferreira, C.S.S., Keizer, J.J., Ritsema, C., 2015. Strategies to prevent forest fires and techniques to reverse degradation processes in burned areas. Catena 128, 224–237 (this issue). Fleskens, L., Stringer, L.C., 2014. Land management and policy responses to mitigate desertification and land degradation. Land Degrad. Dev. 1–4. http://dx.doi.org/10. 1002/ldr.2272. Gkiougkis, I., Kallioras, A., Pliakas, F., Pechtelidis, A., Diamantis, V., Diamantis, I., Ziogas, A., Dafnis, I., 2014. Assessment of soil salinization at the eastern Nestos river delta, N.E. Greece. Catena http://dx.doi.org/10.1016/j.catena.2014.06.024 (Available online 17 July 2014, ISSN 0341-8162). Hessel, R., Reed, M.S., Geeson, N., Ritsema, C., van Lynden, G., Karavitis, C.A., Schwilch, G., Jetten, V., Burger, P., van der Werff ten Bosch, M.J., Verzandvoort, S., van den Elsen, E., Witsenburg, K., 2014. From framework to action: the DESIRE approach to combat desertification. Environ. Manag. http://dx.doi.org/10.1007/s00267-014-0346-3. Kato, E., Ringler, C., Yesuf, M., Bryan, E., 2011. Soil and water conservation technologies: a buffer against production risk in the face of climate change? Insights from the Nile basin in Ethiopia. Agric. Econ. 42, 593–604. http://dx.doi.org/10.1111/j.1574-0862. 2011.00539.x. Kosmas, C., Kairis, O., Karavitis, C., Acikalin, S., Alcalá, M., Alfama, P., Atlhopheng, J., Barrera, J., Belgacem, A., Solé-Benet, A., Brito, J., Chaker, M., Chanda, R., Darkoh, M., Ermolaeva, O., Fassouli, V., Fernandez, F., Gokceoglu, C., Gonzalez, D., Gungor, H., Hessel, R., Khatteli, H., Khitrov, N., Kounalaki, A., Laouina, A., Magole, L., Medina, L., Mendoza, M., Mulale, K., Ocakoglu, F., Ouessar, M., Ovalle, C., Perez, C., Perkins, J., Pozo, A., Prat, C., Ramos, A., Ramos, J., Riquelme, J., Ritsema, C., Romanenkov, V., Sebego, R., Sghaier, M., Silva, N., Sizemskaya, M., Sonmez, H., Taamallah, H., Tezcan, L., de Vente, J., Zagal, E., Zeiliguer, A., Salvati, L., 2014. An exploratory analysis of land abandonment drivers in areas prone to desertification. Catena http://dx.doi. org/10.1016/j.catena.2014.02.006 (ISSN 0341-8162).
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Lal, Rattan, 2004. Soil carbon sequestration impacts on global climate change and food security. Science 304 (5677), 1623–1627. Rajesh, Shruthi B.V., Kerle, Norman, Jetten, Victor, Abdellah, Laouina, Machmach, Issam, 2014. Quantifying temporal changes in gully erosion areas with object oriented analysis. Catena http://dx.doi.org/10.1016/j.catena.2014.01.010 (Available online 11 February 2014, ISSN 0341-8162). Desire for Greener Land. Options for Sustainable Land Management in Drylands. In: Schwilch, G., Hessel, R., Verzandvoort, S. (Eds.), CDE, Alterra — Wageningen UR, ISRIC — World Soil Information and CTA — Technical Centre for Agricultural and Rural Cooperation. University of Bern, Bern, Switzerland, and Wageningen, The Netherlands (ISBN 978-94-6173-329-0.). Shakesby, Richard A., Bento, Célia P.M., Ferreira, Carla S.S., Ferreira, António J.D., Stoof, Cathelijne R., Urbanek, Emilia, Walsh, Rory P.D., 2013. Impacts of prescribed fire on soil loss and soil quality: an assessment based on an experimentally-burned catchment in central Portugal. Catena http://dx.doi.org/10.1016/j.catena.2013.03.012 (Available online 21 April 2013, ISSN 0341-8162). De Pina Tavares, J., Baptista, I., Ferreira, A.J.D., Amiotte-Suchet, P., Coelho, C., Gomes, S., Amoros, R., Dos Reis, E.A., Mendes, A.F., Costa, L., Bentub, J., Varela, L., 2015. Assessment and mapping the sensitive areas to desertification in an insular Sahelian mountain region Case study of the Ribeira Seca Watershed, Santiago Island, Cabo Verde. Catena 128, 214–223 (this issue). UNCCD, 2012. Desertification Land Degradation & Drought (DLDD) - Some Global Facts & Figures. http://www.unccd.int/Lists/SiteDocumentLibrary/WDCD/DLDD%20Facts.pdf. UNEP, 1994. United Nations Convention to Combat Desertification in those countries experiencing serious drought and/or desertification, particularly in Africa. United Nations Environment Programme for the Convention to Combat Desertification (CCD), Interim Secretariat for the CCD, Geneva. UNEP, 1997. World Atlas of Desertification, In: Middleton, N., Thomas, D.S.G. (Eds.), 2nd edition Edward Arnold, London, UK (182).
Erik van den Elsen Soil Physics and Land Use team, Alterra, Wageningen University and Research (WUR). P.O. Box 47, 6700 AA Wageningen, The Netherlands Corresponding author. E-mail address: [email protected]. Victor Jetten Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
Contents lists available at ScienceDirect
Catena journal homepage: www.elsevier.com/locate/catena
Preface
Combatting desertification using a multidisciplinary approach
1. Introduction Internationally, recognition and awareness is growing that soil is one of the most important and, at the same time, most vulnerable resources to mankind. Soil is not only crucial for food production, but also an important regulating factor in mitigation of climate change through e.g. storage of carbon (Lal et al., 2004) or retention of water (Kato et al., 2011). The loss of this valuable resource through various processes is especially prominent in areas where soil is already under pressure from harsh natural conditions; the arid regions in the world. Drylands, cover almost 40% of the world land mass. The United Nations Committee for Combatting Desertification (UNCCD) estimates that total land degradation affects 1.9 billion hectares of land worldwide, while 24 billion tons of fertile soil actually disappears on a yearly basis (UNCCD, 2012). 2. Finding solutions for desertification using an integrated approach — the DESIRE project With more than one billion people at risk, combating desertification is essential to ensuring long-term productivity of inhabited drylands. Desertification is generally defined as land degradation in arid, semiarid and dry sub-humid areas resulting from various factors, including climatic variations and human activities. In this definition, land degradation refers to the loss of biological or economic productivity of soil and local water resources, land surface and vegetation including crops (UNEP, 1994; UNEP, 1997). Promising sustainable land management (SLM) strategies exist — but information about them is often not effectively shared. Consequently they remain underutilized, and degradation in drylands continues. The DESIRE project (DESIRE — “Desertification mitigation and remediation of land — a global approach for local solutions”) strove to find solutions for these pressing issues by developing tailor-fit solutions specific to the 18 case study sites where the ‘DESIRE approach’ was applied, involving local stakeholders in the entire process from assessment to local implementation. Project activities were successfully implemented between 2007 and 2012 and results are being applied in multiple ways, as is shown in a number of research papers presented here. The dynamic and multi-dimensional nature of land degradation makes accurate assessment of the problems and development of appropriate responses a difficult challenge. Existing assessment methods rarely integrate various different components of land degradation, and local communities are seldom able to improve the sustainability of their land management without proper guidance and related incentives. Although western science has traditionally played a key role in determining the extent of land degradation and exploring its causes
http://dx.doi.org/10.1016/j.catena.2014.10.001 0341-8162/© 2014 Published by Elsevier B.V.
and drivers, integrated approaches for dealing with degradation itself have until recently not been available. 3. Involve the community — key for success The UNCCD highlights the importance of both scientific and community based approaches, and promotes integrated action to combat desertification. Actions must emphasize multi-stakeholder participation to enable local people and NGOs to reverse land degradation through self-help, in an environment enabled by governments and fully integrated into national policies. What is needed is an approach that combines scientific rigour and accuracy with relevance and sensitivity to local perspectives and local context. Conservationists, land managers and local communities need to work together towards shared, selfdefined goals. The basis of the DESIRE project was developing a universally applicable approach for identifying, prioritizing, testing, evaluating and implementing appropriate SLM technologies and tools to inform decision makers. The DESIRE approach, consisting of five fundamental steps, can be applied by agricultural advisors, government institutions, or any project that aims to combat land degradation, locally or regionally. Details about this method can be found on the DESIRE project website (DESIRE, 2013) and in the book ‘Desire for Greener Land’ (Schwilch et al., 2012), that describes the project in detail. 4. Project objectives The first objective of DESIRE was to look at degradation and desertification processes in an integrated way, in order to review the cause and effect links and give conservation measures a sound scientific basis. The second objective was to improve the definition of suitable indicators for both qualitative and quantitative evaluation of the land degradation and desertification status in the selected study regions, while the third objective of DESIRE was to assess and develop promising conservation measures using a participatory approach with stakeholder groups. This ensured that the measures were practical, acceptable and affordable for the people who had to implement them, and still kept evaluation of their effectiveness solidly science based. The fourth objective was to evaluate mitigation and remediation measures on a larger than local scale, using a set of spatial models and geo-information tools that permit the evaluation of both on-site and off-site effects at various scales. The fifth objective of DESIRE was to disseminate the results, guidance and decision support tools in suitable formats for all relevant stakeholders. This special section contains a number of papers covering results of the scientific research that are the product of the project objectives
212
Preface
mentioned above. The papers presented here focus on biophysical research, while a special issue in Land Degradation and Development (Fleskens et al., 2014) focuses on some of the unique approaches used in the DESIRE project, and the special section in Environmental Management (Hessel et al., 2014) highlights the perspectives of multiple stakeholder communities living in dryland areas. A concise overview of the research papers presented in this special section is given below. 5. Biophysical research — the basis for reaching the project goals Shakesby et al. (2013) report on the impacts of prescribed fire on soil loss and soil quality in the Portuguese Vale Torto catchment, the study area selected for the DESIRE project. Portugal has been a victim of frequent forest wildfires during the last 50 years. The semi-arid climate found in Portugal makes burned hill slopes vulnerable to erosion and causes, besides loss of soil, loss of organic matter and nutrients. One method to reduce the risk of fires and control the character of fire itself, is to reduce the amount of available (ground) fuel using prescribed or controlled fires. The disadvantage of this method is, again, its impact on soil quality and risk of soil degradation after the vegetation has disappeared. After a fire, the (almost) bare soils are being exposed to rainfall events that can cause severe surface runoff, taking along soil, organic matter and nutrients. The paper of Shakesby et al. describes the loss of soil organic matter and some nutrients after a forest fire, and directly connects to the first objective of the DESIRE project. For the prescribed fire a hill slope was selected and various parameters before and after the fire were analysed. The biggest decline in organic matter and nutrients occurred in the top 2 cm of the slope, but this was only 2.9%. However, the authors conclude that the analysis has taken place a short time after the fire and to get a better picture, the area should be monitored for a longer period. Rajesh et al. (2014) investigate and quantify temporal changes in gully erosion areas using object oriented analysis. The results of this PhD study enable the use of satellite observations to estimate the speed at which erosion gullies develop over time. This, in turn, delivers valuable information about the effectiveness of land management options to reduce land degradation, and is therefore a useful tool for monitoring and evaluating measures quickly and at a larger scale. The study includes improved procedures for mapping gully features from Ikonos-2 and GeoEye-1 data (optical imaging) by using contrast and edge filter information and thereby improving procedures for recognizing potential gully systems. One important new feature was the use of erosion process knowledge, improving the quality of the analysis further. The complex gully systems were better identified semi-automatically than was possible by manual digitization; in particular the finer edges of the gully systems, which in turn led to better quantification of changes in the gully systems. The rule-set for analysing satellite data developed in this study, promises to be applicable in other areas with minor adaptations. This paper does not directly contribute to one of the project objectives, but improves the accuracy of assessing gully erosion development in time. Ferreira et al. (2015–this issue) present a review of methods for remediating potential damage to soils in burnt Mediterranean areas. A big problem is that soils being affected by forest fires are most vulnerable to soil erosion directly after a fire has occurred, thereby leaving little time for taking effective remediation measures. The most effective measures for preventing soil loss through erosion were those that enhance infiltration of water, thereby reducing surface runoff. The authors not only describe measures that can be taken directly after a forest fire, but also preventative strategies and (planning) techniques that limit the post-fire effects or enhance or simplify restoration. As in the paper of Shakesby described earlier, prescribed fires are discussed as are preventive afforestation techniques. Also the locations where the restoration or prevention measures are to be deployed proved to be important. At the end of the paper, a table is presented summarizing
the various techniques together with references, implementation costs, manpower needed for implementation and different ecological properties. This paper directly ties into the third objective of the project (developing promising conservation measures) by giving a thorough overview of available measures, their advantages and disadvantages, thereby offering a valuable checklist for stakeholders in forest fire prone areas in the Mediterranean. Kosmas et al. (2014) present a paper about using an indicator system for analysing the phenomenon of land abandonment in 10 DESIRE study sites in the Mediterranean region, Eastern Europe, Latin America, Africa and Asia. This paper thereby fulfils the second objective of the DESIRE project by improving the definition of suitable indicators for both qualitative and quantitative evaluation of the land degradation and desertification status in drylands. Land abandonment is a phenomenon that often materializes from socio-economic motives but as a result can also have serious environmental implications. Land abandonment is defined as a change in land use that moves from a traditional or recent pattern to another, less intensive pattern. The authors in this study focus on the regional scale drivers using drivers, as promoted by the UNCCD, for simplifying reality to make complex processes quantifiable. From a candidate set of 48 biophysical and socioeconomic indicators they constructed an indicator system by using available classification systems, ranking based on existing research data and expert opinion. Using this indicator system, a Pairwise Spearman rank correlation analysis between land abandonment and selected biophysical and socioeconomic drivers was performed, thereby finding a significant correlation between land abandonment and eight (mainly socioeconomic) variables; land fragmentation, rainfall seasonality, population density, runoff water storage, elderly index and farm size were the indicators mostly associated to land abandonment. The presented methodology proves to be a valuable tool for identifying key indicators that affect land abandonment at different spatial scales, in specific dryland areas under local conditions. Gkiougkis et al. (2014) analyse the process of soil salinization, the prominent cause of land degradation in the Nestos river delta in the north-east of Greece. They present a hydrological, hydrogeological and geological analysis of the DESIRE study area that includes field and laboratory data from 2007, 2008 and 2009. The main reason for the salinization of the area is the presence and use of saline groundwater that has intruded from the nearby coastline, together with limited natural drainage of the soils. The authors present a number of traditional solutions for the salinization problem; attaining a better control of the groundwater table, improving the soil drainage potentials and the use of calcium for leaching out the exchangeable sodium are the most promising. Along with some more innovative, promising, measures presented are irrigation with treated waste water, automated irrigation control and use of crops resistant to high salt concentrations. The lack of sufficient amounts of freshwater remains the largest problem. This paper fulfils objective number four; evaluating mitigation and remediation measures at a larger scale. In the final paper of this special section, De Pina Tavares et al. (2015– this issue) is also connected to the fourth project objective as mentioned above, and presents a study about the sensitivity to desertification in one of the DESIRE study areas, the Ribeira Seca watershed on Cape Verde. This area is sensitive to land degradation due to the steep terrain and arid climate. The results are presented as desertification sensitivity maps generated using the MEDALUS model and six quality indices derived from climate, soil, vegetation, land management, erosion and a number of social parameters. The study presents a valuable tool for pinpointing the most vulnerable locations and areas that could benefit most from preventative measures against land degradation. The papers presented in this special section provide insight into the broad field of research that is involved in trying to tackle the complex problems of land degradation and desertification. This section in CATENA mainly accentuates the biophysical research aspect of the DESIRE project, opposed to the social and economic aspects of the
Preface
project. This wide scope of subjects in the total collection of presented papers is the result of the integrated approach that was chosen for this project. Throughout the papers, the value added by the integration of different disciplines becomes clear; this is even more apparent in the main result of the DESIRE project, the ‘DESIRE approach’, as presented in the DESIRE book. The DESIRE project is a clear example of the empowerment and productivity that can result from scientific research that uses an integrated, multi-disciplinary approach. It is the hope of all participants in the DESIRE project that these results will inspire more research using the DESIRE approach as a tool — where, in the end, the results are greater than the sum of the parts. References DESIRE, 2013. The DESIRE Project: Desertification Mitigation and Remediation of Land — A Global Approach for Local Solutions. Project website. http://www.desire-project.eu. Ferreira, A.J.D., Alegre, S.P., Coelho, C.O.A., Shakesby, R.A., Páscoa, F.M., Ferreira, C.S.S., Keizer, J.J., Ritsema, C., 2015. Strategies to prevent forest fires and techniques to reverse degradation processes in burned areas. Catena 128, 224–237 (this issue). Fleskens, L., Stringer, L.C., 2014. Land management and policy responses to mitigate desertification and land degradation. Land Degrad. Dev. 1–4. http://dx.doi.org/10. 1002/ldr.2272. Gkiougkis, I., Kallioras, A., Pliakas, F., Pechtelidis, A., Diamantis, V., Diamantis, I., Ziogas, A., Dafnis, I., 2014. Assessment of soil salinization at the eastern Nestos river delta, N.E. Greece. Catena http://dx.doi.org/10.1016/j.catena.2014.06.024 (Available online 17 July 2014, ISSN 0341-8162). Hessel, R., Reed, M.S., Geeson, N., Ritsema, C., van Lynden, G., Karavitis, C.A., Schwilch, G., Jetten, V., Burger, P., van der Werff ten Bosch, M.J., Verzandvoort, S., van den Elsen, E., Witsenburg, K., 2014. From framework to action: the DESIRE approach to combat desertification. Environ. Manag. http://dx.doi.org/10.1007/s00267-014-0346-3. Kato, E., Ringler, C., Yesuf, M., Bryan, E., 2011. Soil and water conservation technologies: a buffer against production risk in the face of climate change? Insights from the Nile basin in Ethiopia. Agric. Econ. 42, 593–604. http://dx.doi.org/10.1111/j.1574-0862. 2011.00539.x. Kosmas, C., Kairis, O., Karavitis, C., Acikalin, S., Alcalá, M., Alfama, P., Atlhopheng, J., Barrera, J., Belgacem, A., Solé-Benet, A., Brito, J., Chaker, M., Chanda, R., Darkoh, M., Ermolaeva, O., Fassouli, V., Fernandez, F., Gokceoglu, C., Gonzalez, D., Gungor, H., Hessel, R., Khatteli, H., Khitrov, N., Kounalaki, A., Laouina, A., Magole, L., Medina, L., Mendoza, M., Mulale, K., Ocakoglu, F., Ouessar, M., Ovalle, C., Perez, C., Perkins, J., Pozo, A., Prat, C., Ramos, A., Ramos, J., Riquelme, J., Ritsema, C., Romanenkov, V., Sebego, R., Sghaier, M., Silva, N., Sizemskaya, M., Sonmez, H., Taamallah, H., Tezcan, L., de Vente, J., Zagal, E., Zeiliguer, A., Salvati, L., 2014. An exploratory analysis of land abandonment drivers in areas prone to desertification. Catena http://dx.doi. org/10.1016/j.catena.2014.02.006 (ISSN 0341-8162).
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Lal, Rattan, 2004. Soil carbon sequestration impacts on global climate change and food security. Science 304 (5677), 1623–1627. Rajesh, Shruthi B.V., Kerle, Norman, Jetten, Victor, Abdellah, Laouina, Machmach, Issam, 2014. Quantifying temporal changes in gully erosion areas with object oriented analysis. Catena http://dx.doi.org/10.1016/j.catena.2014.01.010 (Available online 11 February 2014, ISSN 0341-8162). Desire for Greener Land. Options for Sustainable Land Management in Drylands. In: Schwilch, G., Hessel, R., Verzandvoort, S. (Eds.), CDE, Alterra — Wageningen UR, ISRIC — World Soil Information and CTA — Technical Centre for Agricultural and Rural Cooperation. University of Bern, Bern, Switzerland, and Wageningen, The Netherlands (ISBN 978-94-6173-329-0.). Shakesby, Richard A., Bento, Célia P.M., Ferreira, Carla S.S., Ferreira, António J.D., Stoof, Cathelijne R., Urbanek, Emilia, Walsh, Rory P.D., 2013. Impacts of prescribed fire on soil loss and soil quality: an assessment based on an experimentally-burned catchment in central Portugal. Catena http://dx.doi.org/10.1016/j.catena.2013.03.012 (Available online 21 April 2013, ISSN 0341-8162). De Pina Tavares, J., Baptista, I., Ferreira, A.J.D., Amiotte-Suchet, P., Coelho, C., Gomes, S., Amoros, R., Dos Reis, E.A., Mendes, A.F., Costa, L., Bentub, J., Varela, L., 2015. Assessment and mapping the sensitive areas to desertification in an insular Sahelian mountain region Case study of the Ribeira Seca Watershed, Santiago Island, Cabo Verde. Catena 128, 214–223 (this issue). UNCCD, 2012. Desertification Land Degradation & Drought (DLDD) - Some Global Facts & Figures. http://www.unccd.int/Lists/SiteDocumentLibrary/WDCD/DLDD%20Facts.pdf. UNEP, 1994. United Nations Convention to Combat Desertification in those countries experiencing serious drought and/or desertification, particularly in Africa. United Nations Environment Programme for the Convention to Combat Desertification (CCD), Interim Secretariat for the CCD, Geneva. UNEP, 1997. World Atlas of Desertification, In: Middleton, N., Thomas, D.S.G. (Eds.), 2nd edition Edward Arnold, London, UK (182).
Erik van den Elsen Soil Physics and Land Use team, Alterra, Wageningen University and Research (WUR). P.O. Box 47, 6700 AA Wageningen, The Netherlands Corresponding author. E-mail address: [email protected]. Victor Jetten Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands