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Thresholds of Environmental Sustainability

Final Report Summary - THRESHOLDS (Thresholds of Environmental Sustainability)

The THRESHOLDS project aimed to contribute to the progress of sustainability science and to the improvement of sustainable policy formulation, in order to create a conceptual basis for the justification of a precautionary approach application. It confronted the complex behaviour of ecosystems, through the development and evaluation of methods and tools, which were applied in European coastal zones, where policy needs were pressing and involved increased levels of complexity.

The specific THRESHOLDS objectives were to:
1. develop scientific tools to define critical values of drivers, or else thresholds, beyond which the affected ecosystems would be subject to irreversible changes;
2. perform externality assessments to estimate the monetary value of the impacts associated to thresholds' exceedance;
3. produce policy recommendations to assist coastal managers in dealing with thresholds of environmental sustainability.

The project initially focused on the theoretical formulation of externality valuation and non-linear cost-pressure relationships, based on environmental economics and social sciences. A four quadrant diagram was created, assisting the development of techniques for assessing the impact of hysteresis, uncertainty and thresholds' exceedance. Moreover, guidelines on methods to evaluate environmental damages in coastal ecosystems were formulated, including specific notes on habitats and biodiversity, health, recreation and amenity, cultural objects and travel or work time. It was though noted that the impacts of ecosystem damaging were not always quantifiable in economic terms.

The project identified the indicators of irreversible ecosystems' impacts based on theoretical analyses. New tools were developed, with increased simulation power and generality compared to existing alternatives. The mathematical theory of bifurcations was extensively utilised for this purpose. It occurred that systems crossing an ecological threshold exhibited specific characteristics, such as changes in mean values and variances of individual system components, as well as changes in the mass flows and functional relationships between them.

Furthermore, nutrient related thresholds, such as eutrophication or toxic algal blooms, were thoroughly examined. The applied methodology combined the published results of previous research attempts to address a set of related hypotheses and to identify critical values. The toolbox of statistical and mathematical techniques, designed as part of the project, was utilised to identify nutrient thresholds for coastal ecosystems.

A similar analysis was undertaken to determine the effects of contaminants at molecular, individual, population and ecosystem levels. The dependence of pollutants on nutrients' conditions was also investigated. The complexity of the identified links between different pollution sources and the environment highlighted the necessity for integrated environmental protection policies.

Furthermore, models were developed to obtain phytoplankton nutrient limitation indicators. It occurred that microbial diversity in natural systems was related to basic functional properties of the communities, such as the resource use efficiency and the stability.

THRESHOLDS methodologies were integrated and applied to European case studies, which were selected to be representative of different driving forces and pressures on the coastal zone and to extend from local to European level. The application outcomes enabled the identification of available policy options and the development of a theoretical framework for their application. General guiding principles for coastal zones' management were formulated through the alternative scenarios' assessment. The proposed practices referred to nutrient loadings, marine fish farming, contaminants' treatment, thresholds' evaluation and assessment and, finally, implication of adaptive policies. In addition, generic strategic recommendations were formulated in order to assist decision making at an international level.

THRESHOLDS resulted in numerous conclusions and developed software tools, which were either directly exploitable or provided the basis for future progress in the sustainability field. The acquired knowledge was disseminated through a set of targeted activities, such as publications, presentations in conferences, establishment of a project website and participation in academic educational workshops.

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