Developing an analytical framework for assessing progress toward ecosystem-based management

Ecosystem-based management (EBM) has become a key instrument of contemporary environmental policy and practice. Given the increasingly important role of EBM, there is an urgent need for improved analytical approaches to assess if and to what extent EBM has been accomplished in any given case. Drawing on the vast literature on EBM, we identify five key ecosystem aspects for assessment. By linking these aspects to four phases of management, we develop an interdisciplinary, analytical framework that enables a high-resolution and systematic assessment of the degree of specificity and integration of ecosystem aspects in an EBM. We then apply the framework to evaluate five coastal EBM initiatives in Sweden, four on the Baltic coast and one on the west coast. Our results demonstrate our framework’s usefulness for in-depth and continuous assessments of processes aiming for EBM, and also provide an empirical basis for inferences about the key challenges for successful EBM.     

Toxicity of sediment cores from Yangtze River estuary to zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) embryos

Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10～40 cm), which indicated that the pollution is more serious in recent decades.     

Levels and distribution of Dechloranes in sediments of Lake Taihu,China

The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g^?1 dw and 0.051 to 2.10 ng g^?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake.     

Screening risk areas for sediment and phosphorus losses to improve placement of mitigation measures

Identification of vulnerable arable areas to phosphorus (P) losses is needed to effectively implement mitigation measures. Indicators for source (soil test P, STP), potential mobilization by erosion (soil dispersion), and transport (unit-stream power length-slope, LS) risks were used to screen the vulnerability to suspended solids (SS) and P losses in two contrasting catchments regarding topography, soil textural distribution, and STP. Soils in the first catchment ranged from loamy sand to clay loam, while clay soils were dominant in the second catchment. Long-term SS and total P losses were higher in the second catchment in spite of significantly lower topsoil STP. A higher proportion of areas in the second catchment were identified with higher risk due to the significantly higher risk of overland flow generation (LS) and a significantly higher mobilization risk in the soil dispersion laboratory tests. A simple screening method was presented to improve the placement of mitigation measures.     

Challenges in assessing biological recovery from acidification in Swedish lakes

Since the 1980s, Swedish lakes have in general become less acidified. Assessment of biological recovery is, however, hampered by poor pre-acidification data, confounding effects of climate change, and few lakes with annual sampling of fish and other organisms. Only three critically acidified, but non-limed, lakes had two decades of fish monitoring. The lakes had not yet recovered to pre-industrial chemical targets. Fish had low species richness compared to other organism groups. Roach (Rutilus rutilus) and/or European perch (Perca fluviatilis) were the dominant fish species, and the acid-sensitive roach had been lost from one of the lakes. Calcium decreased, possibly approaching pre-acidification concentrations, but exceeded minimum levels needed to sustain some Daphnia species. High or increasing levels of total organic carbon, likely due to reduced acidification and climate change, might influence the biological communities in unexpected ways, for example, facilitating more frequent occurrence of the invasive algae Gonyostomum semen.     

Spatio-temporal trends of PCBs in the Swedish freshwater environment 1981–2012

Polychlorinated biphenyls (PCBs) have been monitored in perch (Perca fluviatilis), pike (Esox lucius), and Arctic char (Salvelinus alpinus) in reference lakes since the late 1960s. Temporal trends and spatial patterns are currently monitored in nine and 32 lakes, respectively. Overall, PCB concentrations are decreasing. However, this is not consistent for all congeners across all lakes and species. Perch has comparatively low PCB concentrations relative to suggested target levels, but individual congener concentrations in some lakes are concerningly high. No temporal trend is seen for CB-118 and CB-153 in perch, but significant decreasing trends exist for Arctic char and pike, for which monitoring started earlier than for perch. The lower/higher chlorinated congener ratio decreased over time in most lakes, indicating fewer new emissions. CB-118 and CB-153 concentrations in perch show spatial gradients across Sweden, with higher concentrations found near urban/industrial areas.     

Long-term effects on nitrogen and benthic fauna of extreme weather events: Examples from two Swedish headwater streams

Climate change is expected to cause an increased frequency of extreme events such as heavy floods and major storms. Such stochastic events have an immediate impact on surface water quality, but the long-term effects are largely unknown. In this study, we assess long-term monitoring data from two Swedish headwater catchments affected by extreme weather events. At one site, where nitrogen effects in soil water, groundwater, and stream water were studied after storm-felling and subsequent forest dieback from bark beetle attack, long-term (>5 years) but relatively modest (generally <1 mg L^?1) increases in ammonium (NH₄-N) and nitrate (NO₃-N) concentrations were observed in the various aqueous media. At the other site, where effects on benthic fauna were studied in a stream impacted by extreme geophysical disturbances caused by rainstorm-induced flashflood, only short-term (1 year) effects were revealed both regarding diversity and composition of species.     

Assessing and managing freshwater ecosystems vulnerable to environmental change

Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.     

Anthropogenic oligotrophication via liming: Long-term phosphorus trends in acidified,limed, and neutral reference lakes in Sweden

Restoration of acidified lakes by liming does not, in many cases, improve productivity to a pre-acidified state. We hypothesize that the poor recovery detected in many of these lakes is due to constrained in-lake phosphorous (P) cycling caused by enhanced precipitation of metals in higher pH, limed waters. Long-term (1990–2012) data for 65 limed, circum-neutral (pH 6–8), and acidified lakes in Sweden were analyzed to determine trends for P and potential drivers of these trends. Limed lakes not only had lower mean values and stronger decreasing trends for total P than non-limed lakes, but they also had the highest percentage of decreasing trends (85 %). A P release factor (Hypolimnetic P/Epilimnetic P) was developed to elucidate differences in internal P cycling between lake groups. Consistently, lower P release factors in limed lakes show limitation of internal P cycling during summer months that may be a factor limiting P bioavailability and thus productivity of these systems.     

Contamination levels of polychlorinated biphenyls in wild versus cultivated samples of female and male mussels (Mytilus sp.) from the Northwest Coast of Iberian Peninsula—new application for QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology

A newly analytical method based on QuEChERS extraction followed by gas chromatography with mass spectrometry (GC-MS) analysis was developed and validated for the quantification of 18 PCBs in wild (from Matosinhos Beach, Portugal) and cultivated (from Ria de Arousa, Spain) mussel samples, pooled by sex. Wild animals showed higher PCB levels than cultivated mussels, with males from both origins, presenting an upper contamination profile comparing with females. This fact seems to be correlated with few biometric parameters, but other interdependencies, not addressed herein, such as distinct lipid contents between sexes, as a consequence of the gametogenic stage, may also explain this data. Overall, data reiterate the importance of investigating the presence of PCBs in marine biological samples, which can act both as bioindicators of environmental contamination, either as food quality controls for human health.