Rute Pinto

Δ15N and δ13C in the Mondego estuary food web : Seasonal variation in producers and consumers

Assessments of temporal variation in stable carbon and nitrogen ratios were used to examine seasonal trends of the water column and benthic food webs in the Mondego estuary (Portugal). There was a marked seasonality in weather and water column conditions, including nutrient supply and chlorophyll concentrations. In spite of the pronounced environmental changes, we found little evidence of seasonal variation in delta(13)C and delta(15)N of producers and consumers in the Mondego estuary, with a few notable exceptions. Nitrogen isotope ratios in macrophytes (Zostera noltii, Ulva sp., Enteromorpha sp., and Gracilaria sp.), and in two grazers (Idotea chelipes and Lekanesphaera levii) increased during late summer, with the highest delta(15)N values being measured in July, during a period of elevated temperatures and drought, which may have favored high rates of denitrification and heavier delta(15)N values. The results suggest that stable-isotope values from macrophytes and selected grazers are useful as tracers of seasonal changes in nitrogen inputs into estuaries, and that those of consumers reflect other factors beyond seasonal variations in N and C sources.

Ecosystem services approach for water framework directive implementation

The modern concept of ‘ecosystem services’ has progressed significantly in recent decades. Conceived primarily as a communication tool in the late 1970s to explain societal dependence on nature, it now incorporates economic dimensions and provides help to decision makers for implementing effective conservation policies which support human wellbeing and sustainable development. The founding work appeared in the late 1980s led to the conducting by policymakers of a more systematic assessment of the net monetary value associated with the preservation or restoration of natural areas. Following this work, many case studies have highlighted that ignorance of the value of natural capital into decisions on land use and resources allocation most likely results in degradation and destruction of this natural capital and eventually prove very costly for society. In this paper is presented a research project that investigates the methodological links of the two concepts (Ecosystems Services Approach (ESA) and Water Framework Directive (WFD) – economics). Its main academic innovation will be on assessing the potential “added value” of using the ESA approach and results in Integrated Water Resource Management policies decision and implementation processes, and the related communication and stakeholders’ participation, with a specific focus to WFD.

Mainstreaming Sustainable Decision-making for Ecosystems: Integrating Ecological and Socio-economic Targets within a Decision Support System

Ecosystem sustainable management, and the underlying decision-making process, generally requires the analysis of ecological, social and economic information, integrating both value judgements and policy goals. Since this process can be regarded as complex and tricky, natural resource management requires a well-structured and transparent decision-making process. In this regard, it is necessary to search for and implement sets of measures which can effectively solve emerging problems. Based on the assumption that decisions concerning the management of watersheds may imply trade-offs between their different functions, the intent was to test if software tools, such as MULINO, could be used to enhance multi-level governance of ecosystems. To achieve this, the DPSIR and MCA were incorporated, to analyze and quantify the explicit trade-offs between several types of services provided by estuarine ecosystems and stakeholder objectives. The Mondego Estuary (Portugal) was used as case study. This system is under constant pressure, from both natural and anthropogenic drivers. Urban expansion and tourism were identified as having a strong impact on system development, while agriculture, although declining, had a determinant role in the system’s status. The study evaluated potential alternatives focusing on the water quality improvement goals that could be designed for the system. The MCA ranked several alternatives and pinpointed as the ʺbestʺ option the alternative that combines buffer zones, eco-tourism enhancement, wastewater treatment plant development, the Murraceira trademark and bivalves bio-control. This analysis allowed a simplification of several management objectives; nonetheless, further tests are still required to understand the real connection between these outcomes and decision-makers.

Ecosystem Services in Estuarine Systems: Implications for Management

Estuaries can be considered strategic locations for human settlement, supporting many anthropogenic activities. These pressures are then added to the naturally occurring ones, resulting in many cases in eutrophication processes and water pollution. The integrity of ecosystems functioning, especially concerning the benefits that attain human well-being, can come easily under pressure if not properly managed. Assuming that human well-being relies on the services provided by well-functioning ecosystems, changes in the ecological functioning of a system can have direct and indirect effects on human welfare. However, many of the interrelations between ecosystem functioning and the provision of services still require quantification in estuarine ecosystems. Therefore, it becomes fundamental to understand the complex and intricate relations in estuarine ecosystems, among ecological, social and economic factors, which are fundamental in designing and implementing management policies. Hence, this chapter tries to explore the interrelations between ecosystem functioning and services provision in estuaries, highlighting that linear relationships between biodiversity and services provision are unlikely to occur. A general overview of several pressures influencing biodiversity, functioning and integrity of estuarine systems, as well as their associated services, is also provided. Furthermore, an illustrative example is provided based on the evaluation of the trade-offs among the services provided by the Mondego Estuary (Portugal). Limitations of the methodologies used to assess estuarine services are discussed. The use of this knowledge on natural resources governance is assumed to be the key to attain the sustainable use of these systems.