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Showing papers in "AMBIO: A Journal of the Human Environment in 2007"


Journal ArticleDOI
TL;DR: This work uses atmospheric carbon dioxide concentration as a single, simple indicator to track the progression of the Anthropocene, the current epoch in which humans and the authors' societies have become a global geophysical force.
Abstract: We explore the development of the Anthropocene, the current epoch in which humans and our societies have become a global geophysical force. The Anthropocene began around 1800 with the onset of industrialization, the central feature of which was the enormous expansion in the use of fossil fuels. We use atmospheric carbon dioxide concentration as a single, simple indicator to track the progression of the Anthropocene. From a preindustrial value of 270-275 ppm, atmospheric carbon dioxide had risen to about 310 ppm by 1950. Since then the human enterprise has experienced a remarkable explosion, the Great Acceleration, with significant consequences for Earth System functioning. Atmospheric CO2 concentration has risen from 310 to 380 ppm since 1950, with about half of the total rise since the preindustrial era occurring in just the last 30 years. The Great Acceleration is reaching criticality. Whatever unfolds, the next few decades will surely be a tipping point in the evolution of the Anthropocene.

2,585 citations


Journal ArticleDOI
TL;DR: It is concluded that to preserve human health, all efforts need to be made to reduce and eliminate sources of exposure from the large number of marine and freshwater fish and fish-eating species.
Abstract: The paper builds on existing literature, highlighting current understanding and identifying unresolved issues about MeHg exposure, health effects, and risk assessment, and concludes with a consensus statement. Methylmercury is a potent toxin, bioaccumulated and concentrated through the aquatic food chain, placing at risk people, throughout the globe and across the socioeconomic spectrum, who consume predatory fish or for whom fish is a dietary mainstay. Methylmercury developmental neurotoxicity has constituted the basis for risk assessments and public health policies. Despite gaps in our knowledge on new bioindicators of exposure, factors that influence MeHg uptake and toxicity, toxicokinetics, neurologic and cardiovascular effects in adult populations, and the nutritional benefits and risks from the large number of marine and freshwater fish and fish-eating species, the panel concluded that to preserve human health, all efforts need to be made to reduce and eliminate sources of exposure.

1,124 citations


Journal ArticleDOI
TL;DR: In this article, the effects of methylmercury exposure on wild piscivorous fish, birds, and mammals were investigated. But, the authors focused on the common loon, and only limited field-based studies corroborated laboratory-based results.
Abstract: Wild piscivorous fish, mammals, and birds may be at risk for elevated dietary methylmercury intake and toxicity. In controlled feeding studies, the consumption of diets that contained Hg (as methylmercury) at environmentally realistic concentrations resulted in a range of toxic effects in fish, birds, and mammals, including behavioral, neurochemical, hormonal, and reproductive changes. Limited field-based studies, especially with certain wild piscivorous bird species, e.g., the common loon, corroborated laboratory-based results, demonstrating significant relations between methylmercury exposure and various indicators of methylmercury toxicity, including reproductive impairment. Potential population effects in fish and wildlife resulting from dietary methylmercury exposure are expected to vary as a function of species life history, as well as regional differences in fish-Hg concentrations, which, in turn, are influenced by differences in Hg deposition and environmental methylation rates. However, population modeling suggests that reductions in Hg emissions could have substantial benefits for some common loon populations that are currently experiencing elevated methylmercury exposure. Predicted benefits would be mediated primarily through improved hatching success and development of hatchlings to maturity as Hg concentrations in prey fish decline. Other piscivorous species may also benefit from decreased Hg exposure but have not been as extensively studied as the common loon.

905 citations


Journal ArticleDOI
TL;DR: It is agreed that the uncertainty is strongly dependent upon scale and that the question as stated is answerable with greater confidence both very near and very far from major point sources, assuming that the “global pool” is a recognizable “source.”
Abstract: A panel of international experts was convened in Madison, Wisconsin, in 2005, as part of the 8th International Conference on Mercury as a Global Pollutant. Our charge was to address the state of science pertinent to source attribution, specifically our key question was: "For a given location, can we ascertain with confidence the relative contributions of local, regional, and global sources, and of natural versus anthropogenic emissions to mercury deposition?" The panel synthesized new research pertinent to this question published over the past decade, with emphasis on four major research topics: long-term anthropogenic change, current emission and deposition trends, chemical transformations and cycling, and modeling and uncertainty. Within each topic, the panel drew a series of conclusions, which are presented in this paper. These conclusions led us to concur that the answer to our question is a "qualified yes," with the qualification being dependent upon the level of uncertainty one is willing to accept. We agreed that the uncertainty is strongly dependent upon scale and that our question as stated is answerable with greater confidence both very near and very far from major point sources, assuming that the "global pool" is a recognizable "source." Many regions of interest from an ecosystem-exposure standpoint lie in between, where source attribution carries the greatest degree of uncertainty.

792 citations


Journal ArticleDOI
TL;DR: Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability.
Abstract: Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet society's unprecedented challenges.

762 citations


Journal ArticleDOI
TL;DR: To effectively reduce cyanobacteria blooms and overall signs of eutrophication, reductions in both nitrogen and phosphorus external loads appear essential.
Abstract: Eutrophication of the Baltic Sea has potentially increased the frequency and magnitude of cyanobacteria blooms. Eutrophication leads to increased sedimentation of organic material, increasing the extent of anoxic bottoms and subsequently increasing the internal phosphorus loading. In addition, the hypoxic water volume displays a negative relationship with the total dissolved inorganic nitrogen pool, suggesting greater overall nitrogen removal with increased hypoxia. Enhanced internal loading of phosphorus and the removal of dissolved inorganic nitrogen leads to lower nitrogen to phosphorus ratios, which are one of the main factors promoting nitrogen-fixing cyanobacteria blooms. Because cyanobacteria blooms in the open waters of the Baltic Sea seem to be strongly regulated by internal processes, the effects of external nutrient reductions are scale-dependent. During longer time scales, reductions in external phosphorus load may reduce cyanobacteria blooms; however, on shorter time scales the inter...

422 citations


Journal ArticleDOI
TL;DR: Oxy-PAHs are important cocontaminants that should be taken into account during risk assessment and remediation of sites with high levels of PAHs, and should be included in monitoring programs at PAH-contaminated sites, even if a number of other toxicologically relevant compounds that may also be present are not monitored.
Abstract: In this paper we show that oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) are important cocontaminants that should be taken into account during risk assessment and remediation of sites with high levels of PAHs. The presented data, which have been collected both from our own research and the published literature, demonstrate that oxy-PAHs are abundant but neglected contaminants at these sites. The oxy-PAHs show relatively high persistency and because they are formed through transformation of PAHs, their concentrations in the environment may even increase as the sites are remediated by methods that promote PAH degradation. Furthermore, we show that oxy-PAHs are toxic to both humans and the environment, although the toxicity seems to be manifested through other effects than those known to be important for polycyclic aromatic compounds in general, that is, mutagenicity and carcinogenicity. Finally, we present data that support the hypothesis that oxy-PAHs are more mobile in the environment than PAHs, due to their polarity, and thus have a higher tendency to spread from contaminated sites via surface water and groundwater. We believe that oxy-PAHs should be included in monitoring programs at PAH-contaminated sites, even if a number of other toxicologically relevant compounds that may also be present, such as nitro-PAHs and azaarenes, are not monitored. This is because oxy-PAH levels are difficult to predict from the PAH levels, because their environmental behavior differs substantially from that of PAHs, and oxy-PAHs may be formed as PAHs are degraded.

403 citations


Journal ArticleDOI
TL;DR: The main conclusion drawn is that changes in Hg loading (increase or decrease) will yield a response in fish MeHg but that the timing and magnitude of the response will vary depending of ecosystem-specific variables and the form of the Hg loaded.
Abstract: In this paper, we synthesize available information on the links between changes in ecosystem loading of inorganic mercury (Hg) and levels of methylmercury (MeHg) in fish. Although it is widely hypothesized that increased Hg load to aquatic ecosystems leads to increases in MeHg in fish, there is limited quantitative data to test this hypothesis. Here we examine the available evidence from a range of sources: studies of ecosystems contaminated by industrial discharges, observations of fish MeHg responses to changes in atmospheric load, studies over space and environmental gradients, and experimental manipulations. A summary of the current understanding of the main processes involved in the transport and transformation from Hg load to MeHg in fish is provided. The role of Hg loading is discussed in context with other factors affecting Hg cycling and bioaccumulation in relation to timing and magnitude of response in fish MeHg. The main conclusion drawn is that changes in Hg loading (increase or decrease) will yield a response in fish MeHg but that the timing and magnitude of the response will vary depending of ecosystem-specific variables and the form of the Hg loaded.

331 citations


Journal ArticleDOI
TL;DR: Integrated records of the co-evolving human-environment system over millennia are needed to provide a basis for a deeper understanding of the present and for forecasting the future.
Abstract: Understanding the history of how humans have interacted with the rest of nature can help clarify the options for managing our increasingly interconnected global system. Simple, deterministic relationships between environmental stress and social change are inadequate. Extreme drought, for instance, triggered both social collapse and ingenious management of water through irrigation. Human responses to change, in turn, feed into climate and ecological systems, producing a complex web of multidirectional connections in time and space. Integrated records of the co-evolving human-environment system over millennia are needed to provide a basis for a deeper understanding of the present and for forecasting the future. This requires the major task of assembling and integrating regional and global historical, archaeological, and paleoenvironmental records. Humans cannot predict the future. But, if we can adequately understand the past, we can use that understanding to influence our decisions and to create a better, more sustainable and desirable future.

317 citations


Journal ArticleDOI
TL;DR: The current status of the natural wetlands in China is described, past problems are reviewed, the funding of billions of dollars to restore degraded wetlands, and the national plan to place 90% of natural wetlands under protection by 2030 are reviewed.
Abstract: Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% costal wetlands) because of the wetland reclamation during China's long history of civilization, and the population pressure and the misguided policies over the last 50 years. Recently, with an improved understanding that healthy wetland ecosystems play a vital role in her sustainable economic development, China started major efforts in wetland conservation, as signified by the policy to return reclaimed croplands to wetlands, the funding of billions of dollars to restore degraded wetlands, and the national plan to place 90% of natural wetlands under protection by 2030. This paper describes the current status of the natural wetlands in China, reviews past problems, and discusses current efforts and future challenges in protecting China's natural wetlands.

275 citations


Journal ArticleDOI
TL;DR: Adaptive management has been widely recommended as a way to deal with extreme uncertainty in natural resource and environmental decision making but attempts to apply adaptive management to issues ranging from restoration of endangered desert fish species to protection of the Great Barrier Reef have been failures.
Abstract: Adaptive management has been widely recommended as a way to deal with extreme uncertainty in natural resource and environmental decision making. The core concept in adaptive management is that policy choices should be treated as deliberate, large-scale experiments; hence, policy choice should be treated at least partly as a problem of scientific experimental design. There have now been upwards of 100 case studies where attempts were made to apply adaptive management to issues ranging from restoration of endangered desert fish species to protection of the Great Barrier Reef. Most of these cases have been failures in the sense that no experimental management program was ever implemented, and there have been serious problems with monitoring programs in the handful of cases where an experimental plan was implemented. Most of the failures can be traced to three main institutional problems: i) lack of management resources for the expanded monitoring needed to carry out large-scale experiments; ii) unwillingness by decision makers to admit and embrace uncertainty in making policy choices; and iii) lack of leadership in the form of individuals willing to do all the hard work needed to plan and implement new and complex management programs.

Journal ArticleDOI
TL;DR: This paper examines the life cycle of mercury from a global perspective and identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations.
Abstract: In the past, human activities often resulted in mercury releases to the biosphere with little consideration of undesirable consequences for the health of humans and wildlife. This paper outlines the pathways through which humans and wildlife are exposed to mercury. Fish consumption is the major route of exposure to methylmercury. Humans can also receive toxic doses of mercury through inhalation of elevated concentrations of gaseous elemental mercury. We propose that any effective strategy for reducing mercury exposures requires an examination of the complete life cycle of mercury. This paper examines the life cycle of mercury from a global perspective and then identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations.

Journal ArticleDOI
TL;DR: Since diet is the most important source of Se in humans, understanding the biogeochemical controls on the distribution and mobility of environmental Se is key to the assessment of Se-related health risks.
Abstract: Selenium (Se) is a naturally occurring metalloid element, which is essential to human and other animal health in trace amounts but is harmful in excess. Of all the elements, Se has one of the narrowest ranges between dietary deficiency ( 400 µg day-1) (1) making it necessary to carefully control intakes by humans and other animals hence the importance of understanding the relationships between environmental exposure and health. Geology exerts a fundamental control on the concentrations of Se in the soils on which we grow the crops and animals that form the human food chain. The Se status of populations, animals and crops vary markedly around the world as a result of different geological conditions. Since diet is the most important source of Se in humans, understanding the biogeochemical controls on the distribution and mobility of environmental Se is key to the assessment of Se-related health risks.

Journal ArticleDOI
TL;DR: It is argued that the lessons from the successful fisheries need to be applied to stop the decline and rebuild those fisheries threatened by excess fishing and local control of fisheries is an essential part of the solution.
Abstract: There are two diverging views of the status and future of the world's fisheries. One group represented largely by academic marine ecologists sees almost universal failure of fisheries management and calls for the use of marine-protected areas as the central tool of a new approach to rebuilding the marine ecosystems of the world. The scientists working in fisheries agencies and many academic scientists see a more complex picture, with many failed fisheries but also numerous successes. This group argues that we need to apply the lessons from the successful fisheries to stop the decline and rebuild those fisheries threatened by excess fishing. These lessons are stopping the competitive race to fish by appropriate incentives for fishing fleets and good governance. The major tool of resetting incentives is granting various forms of dedicated access, including community-based fishing rights, allocation to cooperatives, and individual fishing quotas. Many of the failed fisheries of the world occur in jurisdictions where central governments are not functional, and local control of fisheries is an essential part of the solution.

Journal ArticleDOI
TL;DR: An original account of global land, water, and nitrogen use in support of industrialized livestock production and trade, with emphasis on two of the fastest-growing sectors, pork and poultry, is provided.
Abstract: This paper provides an original account of global land, water, and nitrogen use in support of industrialized livestock production and trade, with emphasis on two of the fastest-growing sectors, pork and poultry. Our analysis focuses on trade in feed and animal products, using a new model that calculates the amount of ‘‘virtual’’ nitrogen, water, and land used in production but not embedded in the product. We show how key meatimporting countries, such as Japan, benefit from ‘‘virtual’’ trade in land, water, and nitrogen, and how key meatexporting countries, such as Brazil, provide these resources without accounting for their true environmental cost. Results show that Japan’s pig and chicken meat imports embody the virtual equivalent of 50% of Japan’s total arable land, and half of Japan’s virtual nitrogen total is lost in the US. Trade links with China are responsible for 15% of the virtual nitrogen left behind in Brazil due to feed and meat exports, and 20% of Brazil’s area is used to grow soybean exports. The complexity of trade in meat, feed, water, and nitrogen is illustrated by the dual roles of the US and The Netherlands as both importers and exporters of meat. Mitigation of environmental damage from industrialized livestock production and trade depends on a combination of direct-pricing strategies, regulatory approaches, and use of best management practices. Our analysis indicates that increased water- and nitrogen-use efficiency and land conservation resulting from these measures could significantly reduce resource costs.

Journal ArticleDOI
TL;DR: Evaluated habitats for major habitats (macroalgae, seagrasses, blue mussel beds, and unvegetated soft bottoms) in a temperate coastal setting and the results are discussed in a management context including accounts of biodiversity, interconnectedness of ecosystems, and potential of economic valuation.
Abstract: Coastal areas are exposed to a variety of threats due to high population densities and rapid economic development. How will this affect human welfare and our dependence on nature's capacity to provide ecosystem goods and services? This paper is original in evaluating this concern for major habitats (macroalgae, seagrasses, blue mussel beds, and unvegetated soft bottoms) in a temperate coastal setting. More than 40 categories of goods and services are classified into provisional, regulating, and cultural services. A wide variety of Swedish examples is described for each category, including accounts of economic values and the relative importance of different habitats. For example, distinguishing characteristics would be the exceptional importance of blue mussels for mitigation of eutrophication, sandy soft bottoms for recreational uses, and seagrasses and macroalgae for fisheries production and control of wave and current energy. Net changes in the provision of goods and services are evaluated for three cases of observed coastal ecosystem shifts: i) seagrass beds into unvegetated substrate; ii) unvegetated shallow soft bottoms into filamentous algal mat dominance; and iii) macroalgae into mussel beds on hard substrate. The results are discussed in a management context including accounts of biodiversity, interconnectedness of ecosystems, and potential of economic valuation.

Journal ArticleDOI
TL;DR: A comparison of the most recent epoch with previous periods shows that policies enacted in the late 1990s to promote forest conservation had no observable impact on reducing deforestation and that deforestation actually increased in some protected areas.
Abstract: Land-cover change in eastern lowland Bolivia was documented using Landsat images from five epochs for all landscapes situated below the montane tree line at approximately 3000 m, including humid forest, inundated forest, seasonally dry forest, and cloud forest, as well as scrublands and grasslands. Deforestation in eastern Bolivia in 2004 covered 45 411 km2, representing ∼9% of the original forest cover, with an additional conversion of 9042 km2 of scrub and savanna habitats representing 17% of total historical land-cover change. Annual rates of land-cover change increased from ∼400 km2 y−1 in the 1960s to ∼2900 km2 y−1 in the last epoch spanning 2001 to 2004. This study provides Bolivia with a spatially explicit information resource to monitor future land-cover change, a prerequisite for proposed mechanisms to compensate countries for reducing carbon emissions as a result of deforestation. A comparison of the most recent epoch with previous periods shows that policies enacted in the late 1990s t...

Journal ArticleDOI
TL;DR: In this paper, the authors show a link between the spatial distribution and growth of gold production across the Guiana Shield in northeast Amazonia and show that an exponential rise in production across an expanding area is primarily a delayed response to the 1971−1978 market flotation of international gold prices.
Abstract: Statistical and spatial analyses of both historical time series and remotely sensed data show a link between the spatial distribution and growth of gold production across the Guiana Shield in northeast Amazonia. Results indicate that an exponential rise in production across an expanding area is primarily a delayed response to the 1971−1978 market flotation of international gold prices. The subsequent 10-fold (2-fold) average nominal (real) price increase has provided a compelling economic incentive to mass exploitation of lower-grade gold deposits. The ground-based and remotely sensed distributions of mining activity are strongly attached to these deposits that dominate the region's gold geology. The presence of these gold-bearing formations in conservation and sustainable timber zones has sparked social conflict and environmental degradation across the region. Left unmanaged, more than a quarter-million square-kilometer area of tropical forest zoned for protection and sustainable management coul...

Journal ArticleDOI
TL;DR: Refusing to eat wild fish is grounded in sustainability and ethical concerns, whereas the decision not to eat farmed fish is associated with a lower expected intrinsic quality rather than shaped by importance attached to sustainability andethical issues.
Abstract: Although sustainability and ethics are of increasing public importance, little research has been conducted to reveal its association with fish consumer behavior. Crosssectional data were collected through a postal selfadministered survey (June 2005) from a sample of 381 Flemish women aged 20–50 years. Consumers attach high perceived importance to sustainability and ethics related to fish. However, this perceived importance is neither correlated with fish consumption frequency nor with general attitude toward eating fish. Refusing to eat wild fish is grounded in sustainability and ethical concerns, whereas the decision not to eat farmed fish is associated with a lower expected intrinsic quality rather than shaped by importance attached to sustainability and ethical issues.

Journal ArticleDOI
TL;DR: The Sea Around Us Project, initiated by the Pew Charitable Trusts and located at the Fisheries Centre, University of British Columbia, Vancouver, Canada, started in mid 1999, is aimed at a reappraisal of fisheries, at a realization that they have become the driver for massive loss of biodiversity in the ocean.
Abstract: The Sea Around Us Project, initiated by the Pew Charitable Trusts in Philadelphia, PA, and located at the Fisheries Centre, University of British Columbia, Vancouver, Canada, started in mid 1999. Its goal was (and still is) to investigate the impact of fisheries on marine ecosystems and to propose policies to mitigate these impacts. Although conceived as a global activity, the project first emphasized the data-rich North Atlantic as a test bed for developing its approaches, which rely on mapping of catch data and indicators of ecosystem health derived from the analysis of long catch time series data. Initial achievements included mapping the decline, throughout the North Atlantic basin, of high-trophic level fishes from 1900 to the present and the presentation of compelling evidence of change in the functioning of the North Atlantic ecosystems, summarized in a 2003 book. The Central and South Atlantic were the next basins to be tackled, with emphasis on the distant-water fleet off West Africa, culminating in a major conference in Dakar, Senegal, in 2002. The project then emphasized the North Pacific, Antarctica, and marine mammals and the multiplicity of tropical Indo-Pacific fisheries before it turned completely global, with all our major analyses and reports (e.g., on the interactions between marine mammals and fisheries, on fuel consumption by fleets, on the catches of small-scale fisheries, on subsidies to fisheries) being based on global studies. Broadly, the work of the project is aimed at a reappraisal of fisheries, from the benign activity that many interested people still perceive them to be, to a realization that they have become the driver for massive loss of biodiversity in the ocean. Moreover, the emphasis on global estimates (rather than local estimates of dubious generality) has allowed the project to contribute to various global initiatives (e.g., developing the Marine Trophic Index for the Convention on Biological Diversity, quantifying marine ecosystem services for the Millennium Ecosystem Assessment), that is, activities that we expect to increase and for which we invite collaboration from academia and environmental nongovernmental organizations.

Journal ArticleDOI
TL;DR: The rationale for a pragmatic semiotics of risk communication between scientists developing flood models and forecasts and those professional groups who are the receptors for flood risk estimates and warnings in the UK is developed.
Abstract: The language and tools of risk and uncertainty estimation in flood risk management (FRM) are rarely optimized for the extant communication challenge. This paper develops the rationale for a pragmatic semiotics of risk communication between scientists developing flood models and forecasts and those professional groups who are the receptors for flood risk estimates and warnings in the UK. The current barriers to effective communication and the constraints involved in the formation of a communication language are explored, focusing on the role of the professional's agenda or “mission” in creating or reducing those constraints. The tools available for the development of this discourse, for both flood warnings in real time and generalized FRM communications, are outlined. It is argued that the contested ownership of the articulation of uncertainties embedded in flood risk communications could be reduced by the development of a formally structured translational discourse between science and professionals in FRM, through which process “codes of practice” for uncertainty estimation in different application areas can be developed. Ways in which this might take place in an institutional context are considered.

Journal ArticleDOI
TL;DR: The observed effects are very variable, because many crustaceans are tolerant to nodularin and because cyanobacteria may complement the diet of grazers in small amounts, and changes in the structure and functioning of the Baltic Sea communities and ecosystems are likely to occur during the cyanobacterial bloom season.
Abstract: Cyanobacteria of the Baltic Sea have multiple effects on organisms that influence the food chain dynamics on several trophic levels. Cyanobacteria contain several bioactive compounds, such as alkaloids, peptides, and lipopolysaccharides. A group of nonribosomally produced oligopeptides, namely microcystins and nodularin, are tumor promoters and cause oxidative stress in the affected cells. Zooplankton graze on cyanobacteria, and when ingested, the hepatotoxins (nodularin) decrease the egg production of, for example, copepods. However, the observed effects are very variable, because many crustaceans are tolerant to nodularin and because cyanobacteria may complement the diet of grazers in small amounts. Cyanobacterial toxins are transferred through the food web from one trophic level to another. The transfer rate is relatively low in the pelagic food web, but reduced feeding and growth rates of fish larvae have been observed. In the benthic food web, especially in blue mussels, nodularin concentrat...

Journal ArticleDOI
TL;DR: Improved wastewater treatment and the use of phosphorus-free detergents in the entire region would drastically decrease phosphorus loads and improve the marine environment, particularly the occurrence of cyanobacterial blooms.
Abstract: We are using the coupled models in a decision support system, Nest, to evaluate the response of the marine ecosystem to changes in external loads through various management options. The models address all the seven major marine basins and the entire drainage basin of the Baltic Sea. A series of future scenarios have been developed, in close collaboration with the Helsinki Commission, to see the possible effects of improved wastewater treatment and manure handling, phosphorus-free detergents, and less intensive land use and live stocks. Improved wastewater treatment and the use of phosphorus-free detergents in the entire region would drastically decrease phosphorus loads and improve the marine environment, particularly the occurrence of cyanobacterial blooms. However, the Baltic Sea will remain eutrophic, and to reduce other effects, a substantial reduction of nitrogen emissions must be implemented. This can only be obtained in these scenarios by drastically changing land use. In a final scenario, we have turned 50% of all agricultural lands into grasslands, together with efficient wastewater treatments and a ban of phosphorus in detergents. This scenario will substantially reduce primary production and the extension of hypoxic bottoms, increase water transparency in the most eutrophied basins, and virtually eliminate extensive cyanobacterial blooms.

Journal ArticleDOI
TL;DR: In this article, the authors present the Tropics of Destruction and Regeneration: Regional Paths of Deletion and Development in the Late Twentieth Century, which is a detailed account of the evolution of tropical forests.
Abstract: The destruction of tropical forests has figured prominently on the global environmental agenda since the 1970s. Yet clearing rates in many tropical regions show no sign of slowing. The consequences of this ongoing environmental disaster are both local and global: loss of water regulation, soils, and biodiversity and emissions of large quantities of carbon dioxide, which are threatening to disrupt the global climate. Understanding the drivers behind tropical deforestation, as a basis for forging effective conservation polices, is therefore an imperative scientific endeavor. The scientific literature is ripe with case studies on the causes of deforestation in different regions and locales. Drawing upon more than a hundred of these, Thomas K. Rudel in Tropical Forests: Regional Paths of Destruction and Regeneration in the Late Twentieth Century tries to synthesize the knowledge amassed. The result is a broad, yet detailed, depiction of the ever-changing landscape of tropical deforestation. Although Tropical Forests is not the first meta-analysis on the causes of tropical deforestation, it differs from, and outshines, its predecessors in several ways. First, whereas many meta-analyses tend to put the quantitative results of the methodology at center stage, the focus here is on building an articulate and coherent narrative from the underlying material. This makes Tropical Forests a highly enjoyable read. In a subject in which it sometimes is hard to see the forest for all the trees, the book succeeds in striking a balance between the details: the complex socioeconomic processes driving deforestation at a local level and the bigger picture: regional patterns and causations behind forest clearing. Second, Tropical Forests attempts to map the temporal shift in the drivers of deforestation, which in some regions have been significant. The focus is on differences between the 1980s and 1990s, but in brief recapitulations Rudel tracks land-use change patterns and destructive practices further back in history, for some regions back to the 16th century. These historical résumés clearly illustrate how land-use decisions at all times have been shaped by a multitude of factors, influenced by both local and global market forces and policy. However, an important lesson from the temporal analysis is that the role of the state in propelling forest clearing has dwindled over time, while the importance of corporations, mainly large soybean producers and logging firms, has increased. Third, Tropical Forests’ most novel contribution to the already large body of literature on tropical deforestation is the focus on forest size and how this factor affects the casual chains leading to forest loss in different regions, as well as the prospects for forest conservation. A case in point is the theory of forest transitions—when and where net deforestation turns from positive to negative—which is analyzed from the angle of small and large forests. In the tropics, forest transitions have occurred in forest-scarce regions, notably South Asia, where local communities have reacted to a rapidly diminishing resource. However, the likelihood of such a transition occurring in the forest-rich regions experiencing the highest levels of deforestation today, i.e., Latin America and Southeast Asia, is negligible. Neither is the kind of forest transition that has occurred in some forest-rich, developed countries (induced by labor scarcity and agricultural intensification [1]) likely to be replicated in Latin America and Southeast Asia, where deforestation chiefly is driven by highly profitable and less labor-intensive industries, cattle ranching, and logging. Consequently, the book mainly sees opportunities for policydriven forest conservation in forest-scarce regions. Somewhat disappointing, it offers little policy advice, or hope, for how to save the large tracts of tropical forests remaining in forest-rich regions. A deliberation on the prospects of climate policy as a tool for reducing deforestation would have been welcome. Discussions on the possibility of including tropical deforestation in a future international climate regime are currently under way in the United Nations Framework Convention on Climate Change, and, given the apparent failure in reducing deforestation rates to date, many people see this as a golden opportunity. Still, doubts can be cast on the possible effect a climate regime alone will have on deforestation rates (2). For a climate regime to be effective, the incentive for reduced deforestation at the international level must translate to an incentive at the local level. How to make this link is an issue that until now has received little attention, and Tropical Forests, unfortunately, does not fill this knowledge gap. However, this shortfall, together with some other minor blemishes (the regional forest maps in the book are close to illegible and the presentation of the quantitative analytical results confounding), weighs light compared to the overall qualities of the book. In all, Tropical Forests is an excellent and well-written piece of work on an urgent topic. It is highly recommended reading both for scientists and for policy makers interested in arresting the ecological crisis tropical deforestation constitutes.

Journal ArticleDOI
TL;DR: An overview on the type of submarine cables that are used for electric transmissions in the sea is given and the character of the magnetic fields they induce are described.
Abstract: With the large scale developments of offshore windpower the number of underwater electric cables is increasing with various technologies applied. A wind farm is associated with different types of cables used for intraturbine, array-to-transformer, and transformer-to-shore transmissions. As the electric currents in submarine cables induce electromagnetic fields there is a concern of how they may influence fishes. Studies have shown that there are fish species that are magneto-sensitive using geomagnetic field information for the purpose of orientation. This implies that if the geomagnetic field is locally altered it could influence spatial patterns in fish. There are also physiological aspects to consider, especially for species that are less inclined to move as the exposure could be persistent in a particular area. Even though studies have shown that magnetic fields could affect fish, there is at present limited evidence that fish are influenced by the electromagnetic fields that underwater cables from windmills generate. Studies on European eel in the Baltic Sea have indicated some minor effects. In this article we give an overview on the type of submarine cables that are used for electric transmissions in the sea. We also describe the character of the magnetic fields they induce. The effects of magnetic fields on fish are reviewed and how this may relate to the cables used for offshore wind power is discussed.

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TL;DR: In this paper, the authors compared the cost efficiency of participatory and conventional biodiversity monitoring methods in Philippine parks and found that, from a government perspective, investment in monitoring that combines scientific with participatory methods is strikingly more effective than a similar level of investment in conventional scientific methods alone in generating conservation management interventions.
Abstract: There is a need for a better understanding of the status of the environment. At the same time, concerns have been raised regarding alienation of the local populace from environmental decisions. One proposed solution is participatory environmental monitoring. When evaluating the usefulness of environmental monitoring, the focus may be on accuracy, as is usually done by scientists, or on efficiency in terms of conservation impact. To test whether investment in participatory biodiversity monitoring makes economic sense for obtaining data for management decisions, we compared the cost efficiency of participatory and conventional biodiversity monitoring methods in Philippine parks. We found that, from a government perspective, investment in monitoring that combines scientific with participatory methods is strikingly more effective than a similar level of investment in conventional scientific methods alone in generating conservation management interventions. Moreover, the local populace seemed to benefit from more secure de facto user rights over land and other resources. Participatory biodiversity monitoring not only represents a cost-effective alternative when conventional monitoring is impossible, but it is also an unexpectedly powerful complementary approach, capable of generating a much higher level of conservation management intervention, where conventional monitoring already takes place.

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TL;DR: Using two iconic World Heritage Areas as case studies, it is outlined how an improved integration of the scientific and social aspects of natural resource management can guide the evolution of multiscale systems of governance that confront and cope with uncertainty, risk, and change in an increasingly human-dominated world.
Abstract: Conventional perceptions of the interactions between people and their environment are rapidly transforming. Old paradigms that view humans as separate from nature, natural resources as inexhaustible or endlessly substitutable, and the world as stable, predictable, and in balance are no longer tenable. New conceptual frameworks are rapidly emerging based on an adaptive approach that focuses on learning and flexible management in a dynamic social-ecological landscape. Using two iconic World Heritage Areas as case studies (the Great Barrier Reef and the Grand Canyon) we outline how an improved integration of the scientific and social aspects of natural resource management can guide the evolution of multiscale systems of governance that confront and cope with uncertainty, risk, and change in an increasingly human-dominated world.

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TL;DR: Increased internal nutrient loading during eutrophication-induced anoxia is suggested to be caused both by altered sediment biogeochemical processes and through reduced or lost bioturbating macrofauna and thereby a reduced stimulatory effect from their activities on natural purification processes of the Baltic Sea ecosystem.
Abstract: This article focuses on the ecological role of benthic macrofauna on nutrient dynamics and benthic-pelagic coupling in the Baltic Sea with relation to eutrophication. Generally, benthic macrofaunal activities have large effects on sediment biogeochemistry and often with stimulatory effects on processes that counteract eutrophication, i.e., denitrification and increased phosphorus retention of the sediment. The degree of faunal impact on such processes varies depending on faunal density and functional group composition. The effect of macrofaunal activities on sediment nutrient dynamics can also result in a higher nitrogen: phosporus ratio of the sediments efflux compared with sediments without macrofauna. Increased internal nutrient loading during eutrophication-induced anoxia is suggested to be caused both by altered sediment biogeochemical processes and through reduced or lost bioturbating macrofauna and thereby a reduced stimulatory effect from their activities on natural purification processes of the Baltic Sea ecosystem.

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TL;DR: It is concluded that social aspects, such as local beliefs and legitimate sanctioning systems, need to be analyzed and incorporated along with biodiversity studies for successful conservation.
Abstract: In the dry forest of southern Madagascar, a region of global conservation priority, formally protected areas are nearly totally absent. We illustrate how the continued existence of unique forest habitats in the Androy region is directly dependent on informal institutions, taboos, regulating human behavior. Qualitative interviews to map and analyze the social mechanisms underlying forest protection have been combined with vegetation analyses of species diversity and composition. Of 188 forest patches, 93% were classified as protected, and in Southern Androy all remaining forest patches larger than 5 ha were protected. Eight different types of forests, with a gradient of social fencing from open access to almost complete entry prohibitions, were identified. Transgressions were well enforced with strong sanctions of significant economic as well as religious importance. Analyses of species diversity between protected and unprotected forests were complicated because of size differences and access restrictions. However, since, for example, in southern Androy >90% of the total remaining forest cover is protected through taboos, these informal institutions represent an important, and presently the only, mechanism for conservation of the highly endemic forest species. We conclude that social aspects, such as local beliefs and legitimate sanctioning systems, need to be analyzed and incorporated along with biodiversity studies for successful conservation.

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TL;DR: The SANBALTS (Simple As Necessary Baltic Long-Term Large-Scale) model as mentioned in this paper is a model of the coupled nitrogen and phosphorus cycles of the Baltic Sea, which has been developed as an integral part of the decision support system Marine Research on Eutrophication's Nest with the overall aim to evaluate management options for reducing Baltic Sea eutrophic degradation.
Abstract: SANBALTS (Simple As Necessary Baltic Long-Term Large-Scale) is a model of the coupled nitrogen and phosphorus cycles. This model has been developed as an integral part of the decision support system Marine Research on Eutrophication's Nest with the overall aim to evaluate management options for reducing Baltic Sea eutrophication. Simulated nutrient and oxygen concentrations as well as transport flows and major biogeochemical fluxes can be analyzed in many different ways, including construction of detailed nutrient budgets and tracing the fate of nutrient inputs. The large amounts of data that exist for this sea makes it possible to validate model results with observations. Major biogeochemical properties of the Baltic Sea are discussed through an analyses of model sensitivity to external forcing and internal parameterizations. Model results emphasize two features that are especially important for ecosystem management: i) impacts of local measures would always be modified by the long-range transports from other regions and ii) the response to significant changes in loads would only be seen after several decades.