CASCADE (CAtastrophic Shifts in drylands: how CAn we prevent ecosystem DEgradation)
One of the most challenging themes in ecology over the last decades is the quest for the understanding of discontinuous changes in ecosystems. Discontinuous shifts have already been observed and analyzed for a wide variety of ecological systems, including lakes, drylands, peatlands, rangelands, marine systems, and musselbeds.
Some of these discontinuous shifts in ecosystems imply undesired and irreversible changes. For example, shallow lakes can suddenly change into eutrophic systems with a large loss in biological diversity.
CASCADE will investigate and analyze a range of dryland ecosystems in southern Europe to obtain a better understanding of sudden shifts in drylands that may lead to major losses in biodiversity and concomitant ecosystem services.
Based on these analyses, CASCADE will develop ways to predict the proximity of the CASCADE's dryland ecosystems to thresholds in such a way that these predictions can be used by policymakers and land users for more sustainable management of drylands worldwide.
CASCADE is assessing current biophysical conditions in healthy, partly-degraded and strongly degraded selected plant-soil systems at study sites in Portugal, Spain (2), Italy, Greece and Cyprus. Then it will determine the effects of imposed drought on plant-soil ecosystem functioning, including facilitation and competition between plants, and how these processes affect plant resource use, survival and growth. Four sites are examining overgrazing and its effects, and the remaining 2 look at the effects of wildfires changing forest to shrub. CASCADE partners responsible for the study sites met in Italy recently to refine ideas for the planned experiments. The number and location of plots have been agreed, plus common guidelines for all measurements and sampling procedures for the plants and soils.