CASCADE: CAtastrophic Shifts in drylands; how CAn we prevent ecosystem DEgradation

One of the most challenging themes in ecology is the quest for understanding discontinuous changes in ecosystems. Some of these shifts can be sudden, catastrophic and irreversible. For example, shallow lakes can suddenly change into eutrophic systems with a large loss in biological diversity, and drylands can catastrophically lose both biological and economic production. CASCADE focusses on dryland systems, some of the most fragile and threatened ecosystems in Europe.

CASCADE aims to:

  1. understand drivers and mechanisms behind ecosystem shifts, and
  2. develop signalling tools and management guidelines to predict and prevent them.
Study area: Castelsaraceno, Italy
Study area: Castelsaraceno, Italy
Study area: Albatera Range, Alicante, Spain
Study area: Albatera Range, Alicante, Spain

Dryland ecosystems, on a European scale, are of major importance both for the services they provide to the local communities and their contribution to pan-European biodiversity. It is becoming increasingly clear that dryland ecosystems have critical thresholds at which the ecosystem shifts abruptly from one state to another. Such shifts in drylands may imply major losses of biological diversity and ecosystem functioning. It is difficult to predict critical transitions, because of the sudden character of the shifts. Yet, for dryland ecosystems, features of the spatial vegetation patterns may serve as indicators of the proximity of thresholds and shifts. There is evidence that sudden shifts in dryland ecosystems can be explained by linkages among the availability of resources such as water and nutrients, vegetation structure (species composition, cover) and livestock grazing habits. Models indicating the role of various tipping points and sudden shifts in dryland systems have been developed and applied to compare predicted shifts with observations in real dryland systems. However, empirical evidence for the basic assumptions in these models regarding the role and impact of such mechanisms is lacking - greatly limiting their pratical applicability for policy makers and land managers.

In light of the above, CASCADE aims to:

  • Improve the understanding of the biogeochemical mechanisms underlying sudden and catastrophic shifts by carrying out a series of experiments that will provide new knowledge on mechanisms and drivers behind sudden shifts in dryland ecosystems. The experiments will be conducted at 6 sites in the Mediterranean region and will include studies on field microcosm, field mesocosm and landscape scales.
  • Develop new models in which the mechanisms will be based on the abovementioned experimentation.
  • Design and evaluate strategies to predict and prevent critical transition in dryland ecosystems that will be based on detectable features of ecosystems and which can be practically and adequately used for ecosystem management by local land managers.
  • Integrate socio-economic factors into the ecological model and undertake scenario analyses of land management strategies, including their multi-scale evaluation with policy makers to enable formulation of policy recommendations for preventive and restorative dryland management
  • Disseminate results to the scientific community, policy makers, advisors and land mangers through multiple readily accessible formats and channels including an information system to be known as CASCADIS

The major expected impacts of this project are to (a) contribute to the understanding and the sustainability of ecological status of dryland ecosystems and to (b) develop early warning signals and management strategies for irreversible shifts in the drylands of Southern Europe. This will be achieved by working on three fronts, which feed into each other:

  • Knowledge impact. Advancement of knowledge on dryland ecosystem functioning with regard to regulating thresholds and sudden anthropogenic or climate induced shifts.
  • Community impact. Development of targeted land use and management measures aimed at preventing catastrophic shifts of ecosystems and preserving ecosystem functions and services for the populations living in the European dryland areas.
  • Policy impact. Feeding knowledge and recommendations to policy makers at the regional, national and international level

CASCADE will get underway with a kick off meeting in the first quarter of 2012.