Catastrophic shifts in drylands

The CASCADE project is an ambitious interdisciplinary research undertaking to unravel the problem of sudden degradation, or catastrophic ecosystem shifts in drylands.

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CASCADE - Catastrophic shifts in drylands - Preventing ecosystem degradation

About the project

Major changes or shifts in ecosystems are often difficult to understand – much less predict. Nevertheless, signs of vegetation loss or soil erosion, for example, may indicate that a particular ecological threshold has almost been reached. When that threshold is crossed – producing a rapid or irreversible transition from one ecosystem state to another, with serious socio-ecological consequences – we speak of a "catastrophic shift". Studying these thresholds and shifts in dryland ecosystems is at the heart of the CASCADE (“Catastrophic shifts in drylands”) project. At present, our understanding of the causes and characteristics of sudden shifts in Mediterranean drylands is limited. It remains difficult to predict if or when a particular shift will occur. Nevertheless, when a shift appears imminent and is considered undesirable by land users, it is critical to know whether anything can be done to prevent it from happening, mitigate its consequences, or even foster recovery.

The CASCADE project (2012-2017) has sought to collect experimental data, implement them in ecological models, and interpret the results to help answer the following questions:

Why and when do catastrophic shifts occur in ecosystems or landscapes?
Why are some ecosystems or landscapes more resilient (i.e. less likely to change) than others?
What can be done to prevent catastrophic shifts?
Can degraded ecosystems or landscapes be restored to previous states?
Is it economically feasible to restore degraded ecosystems or landscapes? Or is it too costly?

Project results and impacts

Under CASCADE, CDE researchers studied land use and land management practices, and their role in preventing catastrophic shifts. Our research approach followed three steps. First, we inventoried, documented, and evaluated any natural resource management practices that were already applied locally. Before coming up with new practices, it only makes sense (economically, environmentally, and socially) to identify and scale up existing practices that are capable of preventing, or even reversing, harmful ecosystem shifts. Second, we developed and applied an effective, simple method to assess the resilience of natural resource management practices. Third, we prepared best-practice guidelines for natural resource managers. These guidelines include technical aspects as well as broader approaches to implementation. We also sought to make region-specific and ecosystem-specific recommendations and principles that make it possible to scale up effective practices.