Doomed to collapse: Why Algerian steppe rangelands are overgrazed and some lessons to help land-use transitions

Guirado

Maestre

2020

Land

Self Cite

From its origins, the concept of desertification has been controversial. The prevailing confusion between two desertification visions, one that considers it as the expansion of deserts and another that emphasizes its anthropogenic component, has been transferred to society. Here we illustrate misunderstandings about desertification using a very illustrative case from the Tabernas-Sorbas Basin (Almeria, Spain), where striking badlands that are often used as an image of desertification coexist with an intensive olive agriculture that is irreversibly deteriorating the only oasis in continental Europe (Los Molinos spring). The olive tree is a traditional Mediterranean dryland crop and until the 1950s only about 200 ha were irrigated in this area. However, the profitability of the crop has caused irrigation to expand to 4400 ha in the last two decades. The process of intensification has been reinforced giving way to super-intensive irrigation, which involves going from 210 to 1550 trees/ha, which in a few years already occupies more than 1500 ha. The effects on the water balance of the aquifer feeding these crops have been severe, and the flow of the Los Molinos spring has gone from more than 40 L/s for the period 1970–2000 to the current 7.28 L/s. Unraveling the mechanisms of land degradation and its main drivers are the first step to propose management actions to achieve a more sustainable use of resources and to combat desertification.

Section: Discussionmentioning

confidence: 99%

Unraveling Misunderstandings about Desertification: The Paradoxical Case of the Tabernas-Sorbas Basin in Southeast Spain

Guirado

Maestre

2020

Land

Self Cite

“…Prevention and mitigation of desertification includes understanding its causes, monitoring and evaluating its progression, and designing and implementing site-specific management strategies [18]. Given the irreversible nature of desertification, it is essential to anticipate the problem [22,49,50]. SAT is a software aimed at contributing to this problematic of the fight against desertification.…”

Section: Discussionmentioning

confidence: 99%

“…Even more, the computational system is ready to be exported to other countries. GDM has been already adapted to study groundwater-dependent oases in Morocco [56]; Alcalá et al [66,48], Greek rangelands [37], and Algerian steppe rangelands [50]. Given that all the UNCCD signatory countries are committed to develop their NPCDs, this kind of tools can help threatened regions to spot desertification processes in their initial stages.…”

Section: Discussionmentioning

confidence: 99%

SAT: A Software for Assessing the Risk of Desertification in Spain

Ibáñez

Alcalá

et al. 2020

Scientific Programming

Self Cite

Desertification is a major global environmental issue exacerbated by climate change. Strategies to combat desertification include prevention which seeks to reverse the process before the system reaches the stable desertified state. One of these initiatives is to implement early warning tools. This paper presents SAT (the Spanish acronym for Early Warning System), a decision support system (DSS), for assessing the risk of desertification in Spain, where 20% of the land has already been desertified and 1% is in active degradation. SAT relies on three versions of a Generic Desertification Model (GDM) that integrates economics and ecology under the predator-prey paradigm. The models have been programmed using Vensim, a type of software used to build and simulate System Dynamics (SD) models. Through Visual Basic programming, these models are operated from the Excel environment. In addition to the basic simulation exercises, specially designed tools have been coupled to assess the risk of desertification and determine the ranking of the most influential factors of the process. The users targeted by SAT are government land-use planners as well as desertification experts. SAT tool is implemented for five case studies, each one of them representing a desertification syndrome identified in Spain. Given the general nature of the tool and the fact that all United Nations Convention to Combat Desertification (UNCCD) signatory countries are committed to developing their National Plans to Combat Desertification (NPCD), SAT could be exported to regions threatened by desertification and expanded to cover more case studies.

“…(iii) SD literature has made rich contributions to approaches informing on the modelling process, including data collection methods, knowledge elicitation/mapping techniques, and policy analysis. e integrated models that allow the implementation of SD are essential to address environmental problems [28][29][30]. e degradation of the environment is forged by the imbalance created between the natural rate of regeneration of resources and their rate of exploitation, which is due to socioeconomic factors.…”

Section: System Dynamics Modelling Sd Modellingmentioning

confidence: 99%

AQUACOAST: A Simulation Tool to Explore Coastal Groundwater and Irrigation Farming Interactions

Ibáñez

Alcalá

2020

Scientific Programming

Self Cite

In the framework of coastal groundwater-dependent irrigation agriculture, modelling becomes indispensable to know how this renewable resource responds to complex (usually not conceptualized nor monitored) biophysical, social, and economic interactions. Friendly user interfaces are essential to involve nonmodeling experts in exploiting and improving models. Decision support systems (DSS) are software systems that integrate models, databases, or other decision aids and package them in a way that decision makers can use. This paper addresses these two issues: firstly with the implementation of a System Dynamics (SD) model in Vensim software that considers the integration of hydrological, agronomic, and economic drivers and secondly with the design of a Venapp, push-button interfaces that allow users access to a Vensim model without going through the Vensim modelling environment. The prototype designed, the AQUACOAST tool, gives an idea of the possibilities of this type of models to identify and analyze the impact of apparently unrelated factors such as the prices of cultivated products, subsidies or exploitation costs on the advance of saltwater intrusion, and the great threat to coastal groundwater-dependent irrigation agriculture systems.