Angheluta Vadineanu

Continental-scale effects of nutrient pollution on stream ecosystem functioning.

Reading the Leaves Excess inputs of nutrients—a type of pollution known as eutrophication—threatens biodiversity and water quality in rivers and streams. Woodward et al. (p. 1438; see the Perspective by Palmer and Febria) studied how one key ecosystem process—leaf-litter decomposition—responds to eutrophication across a large nutrient pollution gradient in 100 European streams. Leaf breakdown was stimulated by low to moderate nutrient concentrations but was inhibited at high rates of nutrient loading. Leaf-litter breakdown rates across 100 European streams offer insights into ecosystem health during eutrophication. Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process—leaf-litter breakdown—in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

Conceptualising Long-Term Socio-ecological Research (LTSER): Integrating the Social Dimension

In order to support the emerging network of long-term ecological research (LTER) sites across Europe, the European Union has launched ALTER-Net, a network aiming at lasting integration of long-term socio-economic, ecological and biodiversity research. Due to its high population density and long history of human habitation, however, Europe’s ecosystems are generally intensively used. Social and natural drivers are so inextricably intertwined that the notion of ‘socio-ecological’ systems is appropriate. Traditional natural science-based approaches are insufficient to understand these integrated systems, as they cannot adequately capture their relevant socio-economic dimensions. This is particularly relevant because the EU launched ALTER-Net has an explicit aim to support sustainability, a goal that requires integration of socio-economic and ecological dimensions. As such, LTER is challenged to significantly expand its focus from ecological to socio-ecological systems, thus transforming itself from LTER to long-term socio-ecological research or LTSER. In order to support this transformation, this chapter explores several approaches for conceptualising socio-economic dimensions of LTSER. It discusses how the socio-economic metabolism approach can be combined with theories of complex adaptive systems to generate heuristic models of society–nature interaction which can then be used to integrate concepts from the social sciences. In particular, the chapter discusses possible contributions from the fields of ecological anthropology and ecological economics and shows how participatory approaches can be integrated with innovative agent-based modelling concepts to arrive at an integrated representation of socio-ecological systems that can help to support local communities to move towards sustainability.

Long-term changes of submerged macrophytes in the Lower Danube Wetland System

Transition towards hypertrophy has affected biodiversity and productivity of most aquatic and wetland systems in the Lower Danube Wetland System (LDWS) over the last two decades. The aquatic macrophytes have been deeply involved in ecosystem reorganization in these circumstances. Representative shallow lakes and channels located in the river floodplain and delta were studied in this period in terms of space distribution, diversity, species composition, primary production and main hydrogeomorphic features (morphometrical and physico-chemical parameters). Changes in submerged vegetation dynamics along two successive decades after 1980 included diminishing areas of about 50% in the Danube Delta, restructuring primary producers by suppressing aquatic weed in some lakes or parts of lakes and decreasing species richness to few populations with upright and floating growth strategy. Biomass production showed different trends, from severe reduction in some lakes and periods to marked increase in other ones, provided by a changed and simplified species structure, generally dominated by Ceratophyllum demersum L. and Potamogeton species. It was concluded that the eutrophication effects are maintaining, modulated by diverse response mechanisms developed by submerged macrophytes. Finally, the main lessons to be learned for the management of aquatic macrophyte-dominated systems in the framework of redesigning the LDWS structures are emphasized on the basis of a large scale and long-term prospect of the Danube River and Black Sea Basins.

Factors affecting light penetration in shallow lakes

Light conditions were studied in six lakes of the Danube Delta for a period of 2 years and were described as a function of 12 independent variables forming a data matrix with more than 1000 sample units. Light extinction was explained in percentage of 64% by phytoplankton, of 11 % by detritus, of 7% by zoo-plankton, of 1.4% by dissolved organic matter and of 0.15 by bacterioplankton. The influence of mineral particles was insignificant. Equations are produced here for the relationship to water turbulence, wind intensity and lake depth. The threshold for full water turbulence was between 7 and 8% for a fluctuation domain of critical winds of 3.2–5.4 m s −1 and for a depth domain of 1–3 m.

Importance of flood zones for nitrogen and phosphorus dynamics in the Danube Delta

The change of concentration of total reactive phosphorus (TRP) and dissolved inorganic nitrogen (DIN) was studied in the lower Danube river and in selected lakes situated in the wetland area of the Danube Delta. The differences Danube Delta in nutrient concentration in the river waters entering the delta and the delta in different sites (especially lakes) of the wetland area are considered to reflect retention in the system. The highest retention was found in periods of moderate and low water level when the surface-to-volume ratio of the lakes was high. In these periods the in-lake concentration of TRP and DIN could be as low as 11 and 23% of the values found in the inflowing river.

Science-policy interfaces for biodiversity: dynamic learning environments for successful impact

To address the pressing problems associated with biodiversity loss, changes in awareness and behaviour are required from decision makers in all sectors. Science-policy interfaces (SPIs) have the potential to play an important role, and to achieve this effectively, there is a need to understand better the ways in which existing SPIs strive for effective communication, learning and behavioural change. Using a series of test cases across the world, we assess a range of features influencing the effectiveness of SPIs through communication and argumentation processes, engagement of actors and other aspects that contribute to potential success. Our results demonstrate the importance of dynamic and iterative processes of interaction to support effective SPI work. We stress the importance of seeing SPIs as dynamic learning environments and we provide recommendations for how they can enhance success in meeting their targeted outcomes. In particular, we recommend building long-term trust, creating learning environments, fostering participation and ownership of the process and building capacity to combat silo thinking. Processes to enable these changes may include, for example, inviting and integrating feedback, extended peer review and attention to contextualising knowledge for different audiences, and time and sustained effort dedicated to trust-building and developing common languages. However there are no ‘one size fits all’ solutions, and methods must be adapted to context and participants. Creating and maintaining effective dynamic learning environments will both require and encourage changes in institutional and individual behaviours: a challenging agenda, but one with potential for positive feedbacks to maintain momentum.

Past and Future Management of Lower Danube Wetlands System: A Bioeconomic Appraisal

The Lower Danube Wetlands System has been and remains one of the largest and most diverse wetlands formations in Europe. It extends over ten thousands square kilometers along the lower Danube river stretch of 840 kilometers long. In the last century several types of management were applied at the LDWS and river catchments and a wide range of structural and functional effects occurred in time. The management system promoted between 1950s and late 1980s was designed according to the principles of neoclassical economic theory. The objectives of this paper are: i) the implementation of holistic approach and management for identifying the past and future drivers, pressures and impacts upon LDWS; ii) use of the methods of biological economics for the assessment of the advantages and disadvantages of past and future strategies and management of the LDWS and iii) identification of the overall goal and targets for future holistic bioeconomic management of the local (IBr), micro-regional (LDWS) and regional (LDC and North-Western Black Sea) biological complexes. As the reference state for LDWS we have adopted that of the beginning of 1960s when no major structural and functional changes had occurred. Increase in demands for more agricultural land and food production, hydropower or for waterway transport as well as for urbanization and industrial use at the Danube river catchments have resulted in significant changes. These together with a set of main actions consisting in: extensive conversion of wetlands into agroecosystems; intensification of auxiliary energy and material inputs into food production systems; point and diffuse pollution; hydrotechnical works and overexploitation of natural resources have been identified as drivers and pressures responsible for a wide range of structural and functional changes which have occurred in the last four decades in the LDWS and North-Western Black Sea. All sets of local and regional impacts are described and viewed as major threats for natural capital and long-term socioeconomic development. The crude estimation of total economic value of the remained wetlands (SIBr) and established polders in the IBr biological complex, allowed a better assessment of the short term and sectoral advantages against long term and holistic disadvantages. The achievements of such analysis described in section 4 clearly suggest the multifunctional role and economic value of self-maintaining wetlands ecosystems compared with monofunctional role and economic value of the human-dependent agroecosystems. It is determined that the economic inefficiency of the former applied mono-functional policy and management at the IBr wetlands system consists on the one hand in the huge cost of wetlands transformation (more than one billion USD) and additional cost for intensive production of crops, which accounted for at least 90 million USD per year (20 per cent higher than the crops market price of 70 million USD per year) and on the other hand in the monetary loss (173 million USD per year) due to cutting off three valuable ecosystem functions by implementing mono-functional farming system. Bearing in mind the difference between the reference and current states of LDWS and the respective economic consequences as well as the long-term objectives of the new established policy in the region, which deals, with: a) biodiversity conservation; b) 40 per cent reduction of the potential nutrient discharges into Black Sea by 2010 and c) sustainable development, we are proposing an operational plan for a holistic bioeconomic management of these wetlands. This plan is, based on the reconstruction of 1500 square kilometers of wetlands in the LDWS and implementing multifunctional farming in LDC and remaining polders in the LDWS. We have also estimated the potential impacts of wetlands reconstruction of LDWS’s functions and its total bioeconomic value.

Observations on the population dynamics of Potamothrix hammoniensis (Michaelsen, 1901) (Tubificidae, Oligochaeta) in Lake Isacova in the Danube Delta

The Danube Delta is one of the widest wetland systems in Europe and Lake Isacova is one of the biggest lakes in the Delta. The oligochaete community in the Lake comprised 52% of the total benthic fauna and Potamothrix hammoniensis (Michaelsen, 1901) (Tubificidae, Oligochaeta) represented more than 90% of the oligochaetes sampled. During September 1991 – August 1994, the proportion of ovigerous individuals of P. hammoniensis represented less than 20% of the total population, with localised differences in the Lake occurring over time. Breeding and cocoon production in the study period started in March of the year, when the water temperature was about 7 °C, and lasted until May 1992 and June 1993, respectively. The newly hatched individuals reached the highest proportion in May. Although large individuals were found again by the end of September (1991) and the beginning of October (1993), no spermatozeugmata in their spermathecae or cocoons were observed during November and October, respectively. Member of this cohort bred and started cocoon deposition during the following spring, after about 11 months of maturation (from April to March). A second, less intensive period of breeding was recorded during August 1992 and this lasted until the beginning of September 1993. However, cocoons from this latter period did not show embryonic growth and hatching until the autumn floods bring oxygenated water to the bottom level. This resulted in a period of rapid development followed by the mass hatching of cocoons. These specimens needed a maximum of 9 month (from October to July) to reach sexual maturity.

Ecosytem Services: A Rapid Assessment Method Tested at 35 Sites of the LTER-Europe Network

Abstract The identification of parameters to monitor the ecosystem services delivered at a site is fundamental to the concept’s adoption as a useful policy instrument at local, national and international scales. In this paper we (i) describe the process of developing a rapid comprehensive ecosystem service assessment methodology and (ii) test the applicability of the protocol at 35 long-term research (LTER) sites across 14 countries in the LTER-Europe network (www.lter-europe.net) including marine, urban, agricultural, forest, desert and conservation sites. An assessment of probability of occurrence with estimated confidence score using 83 ecosystem service parameters was tested. The parameters were either specific services like food production or proxies such as human activities which were considered surrogates for cultural diversity and economic activity. This initial test of the ecosystem service parameter list revealed that the parameters tested were relatively easy to score by site managers with a high level of certainty (92% scored as either occurring or not occurring at the site with certainty of over 90%). Based on this assessment, we concluded that (i) this approach to operationalise the concept of ecosystem services is practical and applicable by many sectors of civil society as a first screen of the ecosystem services present at a site, (ii) this study has direct relevance to land management and policy decision makers as a transparent vehicle to focus testing scenarios and target data gathering, but (iii) further work beyond the scale investigated here is required to ensure global applicability.

Watersheds Management in Romania: Challenges and Opportunities

Sustainable use and development of watersheds become a major target of the national, European and global strategies and policies for sustainable development.