scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Protecting and Restoring Aquatic Ecosystems in Multiple Stressor Environments

01 May 2017-Water Economics and Policy (World Scientific Publishing Co. Pte Ltd)-Vol. 3, Iss: 2, pp 1650011
TL;DR: In this paper, the optimal management of a native fishery in a lake ecosystem subject to risks from pollution and an invasive species is investigated. And the authors find that optimal pollution abatement in absence of both these stressors may turn out to be lower than when either or both are present.
Abstract: Aquatic ecosystems around the globe are under threat from pollution, invasive species, over-exploitation, and other stressors. Given synergistic effects, policy measures to address particular stressors should be developed in tandem with policy measures to address others. We present a bio-economic model that addresses the optimal management of an aquatic ecosystem subject to multiple stressors. Specifically, we consider optimal management of a native fishery in a lake ecosystem subject to risks from pollution and an invasive species. Optimal plans exist for various cases defined by whether, one, both, or neither of the stressor events has occurred. Optimal fishery stocks vary between these cases, and depend on the order in which the stressor event occur if realized. The optimal native stock is the highest in the absence of either stressor. However, the combined influence of the multiple risks can rapidly reduce the probability of maintaining an un-invaded and un-polluted state for long. The synergistic effects of the risks interconnect optimal policies in interesting ways. We find that optimal pollution abatement in absence of both these stressors may turn out to be lower than when either or both stressors are present. The effectiveness of native fish stock in mitigating the risk of alien fish invasion can have a bearing on whether optimal native fish stock and abatement effort are used as substitutes or as complements. Pollution abatement levels that are chosen without consideration of alien invasion risk can lead indirectly to increased societal costs for invasion risk mitigation.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, the authors draw on a diverse interdisciplinary literature to identify challenges for implementing efficient solutions using economic instruments, but also describe why economic research and concern for economic efficiency are of crucial importance to the selection of instruments to address the problem, and propose a general equilibrium economic geography paradigm for research on instrument design and choice.
Abstract: Nutrient pollution is one of the most important problems facing aquatic systems globally. The problem qualifies as a wicked one, involving multiple pollutants from multiple sources interacting in complex ways over space and time along multiple pathways, with uncertainty present at each stage of the process—from pollutant generation to the final ecological and economic impacts. We draw on a diverse interdisciplinary literature to identify challenges for implementing efficient solutions using economic instruments, but also describe why economic research and concern for economic efficiency are of crucial importance to the selection of instruments to address the problem, and propose a general equilibrium economic geography paradigm for research on instrument design and choice.

53 citations

Book ChapterDOI
01 Jan 2019
TL;DR: In this paper, the authors define what a stressor is, how it affects the receptors, and the multiple ways in which stressors interact in river ecosystems, emphasizing the existing literature analyses of the effects of multiple stressors, as well as the outcomes most commonly found.
Abstract: Stressors rarely occur alone in the environment. Particularly in river ecosystems, many stressors often act jointly and produce complex responses. A realistic appraisal positions us in the necessary joint analysis of natural and human-driven stressors. In this chapter, we aim to define what a stressor is, how it affects the receptors, and the multiple ways in which stressors interact. We emphasize the existing literature analyses of the effects of multiple stressors, as well as the outcomes most commonly found. Multiple stressors can affect biodiversity and the functioning of river ecosystems, but also the goods and services that societies derive from rivers. Stressors differ in nature and need to be considered hierarchically, as they may differ in their associated energy as well as in their frequency of occurrence. Direct and indirect feedback between stressor effects result in interactions that range from synergistic to antagonistic and may produce ecological surprises. Ecosystems differ in their resistance and resilience to stressors, and they can show thresholds beyond which critical shifts occur between ecosystem states.

16 citations

Journal ArticleDOI
TL;DR: The health of many marine, coastal, freshwater, and other aquatic ecosystems is inextricably linked to decisions about the management of water quality and quantity as discussed by the authors, and the health of these ecosystems is linked with decisions about water management and quantity.
Abstract: The health of many marine, coastal, freshwater, and other aquatic ecosystems is inextricably linked to decisions about the management of water quality and quantity. In this article we revie...

4 citations


Cites background from "Protecting and Restoring Aquatic Ec..."

  • ...Ranjan and Shortle (2017) show that optimal management of an aquatic system that faces two sources of uncertainty—water...

    [...]

References
More filters
Journal ArticleDOI
TL;DR: The pathology of natural resource management, defined as a loss of system resilience when the range of natural variation in the system is reduced encapsulates the unsustain- able environmental, social, and economic outcomes of command-and-control resource management is discussed in this article.
Abstract: As the human population grows and natural resources decline, there is pressure to apply increas- ing levels of topdown, command, and~control management to natural resources. This is manifested in at- tempts to control ecosystems and in socioeconomic institutions that respond to erratic or surprising ecosystem behavior with more control Command and control, however, usually results in unforeseen consequences for both natural ecosystems and human welfare in the form of collapsing resources, social and economic strife, and losses of biological diversity. We describe the "pathology of natural resource management, " defined as a loss of system resilience when the range of natural variation in the system is reduced encapsulates the unsustain- able environmental, social, and economic outcomes of command~and~ontrol resource management. If natu- ral levels of variation in system behavior are reduced through command-and~ontrol, then the system be- comes less resilient to external perturbations, resulting in crises and surprises. We provide several examples of this pathology in management. An ultimate pathology emerges when resource management agencies, through initial success with command and control, lose sight of their original purposes, eliminate research and monitoring, and focus on efficiency of control They then become isolated from the managed systems and inflexible in structure. Simultaneously, through overcapitalization, society becomes dependent upon com- mand and control, demands it in greater intensity, and ignores the underlying ecological change or collapse that is developing. Solutions to this pathology cannot come from further command and control (regulations) but must come from innovative approaches involving incentives leading to more resilient ecosystems, more flexible agencies, more self-reliant industries, and a more knowledgeable citizenry. We discuss several aspects of ecosystem pattern and dynamics at large scales that provide insight into ecosystem resilience, and we pro- pose a "Golden Rule" of natural resource management that we believe is necessary for sustainabllity: man- agement should strive to retain critical types and ranges of natural variation in resource systems in order to maintain their resiliency.

1,871 citations

Journal ArticleDOI
TL;DR: In this article, the authors review published parallel time-series data on hypoxia and loading rates for inorganic nutrients and labile organic matter to analyze trajectories of oxygen (O2) response to nutrient loading.
Abstract: . The incidence and intensity of hypoxic waters in coastal aquatic ecosystems has been expanding in recent decades coincident with eutrophication of the coastal zone. Worldwide, there is strong interest in reducing the size and duration of hypoxia in coastal waters, because hypoxia causes negative effects for many organisms and ecosystem processes. Although strategies to reduce hypoxia by decreasing nutrient loading are predicated on the assumption that this action would reverse eutrophication, recent analyses of historical data from European and North American coastal systems suggest little evidence for simple linear response trajectories. We review published parallel time-series data on hypoxia and loading rates for inorganic nutrients and labile organic matter to analyze trajectories of oxygen (O2) response to nutrient loading. We also assess existing knowledge of physical and ecological factors regulating O2 in coastal marine waters to facilitate analysis of hypoxia responses to reductions in nutrient (and/or organic matter) inputs. Of the 24 systems identified where concurrent time series of loading and O2 were available, half displayed relatively clear and direct recoveries following remediation. We explored in detail 5 well-studied systems that have exhibited complex, non-linear responses to variations in loading, including apparent "regime shifts". A summary of these analyses suggests that O2 conditions improved rapidly and linearly in systems where remediation focused on organic inputs from sewage treatment plants, which were the primary drivers of hypoxia. In larger more open systems where diffuse nutrient loads are more important in fueling O2 depletion and where climatic influences are pronounced, responses to remediation tended to follow non-linear trends that may include hysteresis and time-lags. Improved understanding of hypoxia remediation requires that future studies use comparative approaches and consider multiple regulating factors. These analyses should consider: (1) the dominant temporal scales of the hypoxia, (2) the relative contributions of inorganic and organic nutrients, (3) the influence of shifts in climatic and oceanographic processes, and (4) the roles of feedback interactions whereby O2-sensitive biogeochemistry, trophic interactions, and habitat conditions influence the nutrient and algal dynamics that regulate O2 levels.

336 citations

Journal ArticleDOI
TL;DR: A simple cost:benefit bioeconomic framework is developed to quantify the net benefits from applying species prescreening and it is shown that this RA program produces positive net economic benefits over the range of reasonable assumptions.
Abstract: International commerce in live organisms presents a policy challenge for trade globalization; sales of live organisms create wealth, but some nonindigenous species cause harm. To reduce damage, some countries have implemented species screening to limit the introduction of damaging species. Adoption of new risk assessment (RA) technologies has been slowed, however, by concerns that RA accuracy remains insufficient to produce positive net economic benefits. This concern arises because only a small proportion of all introduced species escape, spread, and cause harm (i.e., become invasive), so a RA will exclude many noninvasive species (which provide a net economic benefit) for every invasive species correctly identified. Here, we develop a simple cost:benefit bioeconomic framework to quantify the net benefits from applying species prescreening. Because invasive species are rarely eradicated, and their damages must therefore be borne for long periods, we have projected the value of RA over a suitable range of policy time horizons (10–500 years). We apply the model to the Australian plant quarantine program and show that this RA program produces positive net economic benefits over the range of reasonable assumptions. Because we use low estimates of the financial damage caused by invasive species and high estimates of the value of species in the ornamental trade, our results underestimate the net benefit of the Australian plant quarantine program. In addition, because plants have relatively low rates of invasion, applying screening protocols to animals would likely demonstrate even greater benefits.

331 citations

Journal ArticleDOI
TL;DR: Economic analyses show that degraded lakes are significantly less valuable than normal lakes, and the economic benefits of restoring lakes could be used to create incentives for lake restoration.
Abstract: Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

273 citations

Journal ArticleDOI
TL;DR: A multidimensional SES is model to investigate how alternative institutions affect SES stability landscapes and alter tipping points and strong institutions that account for feedback responses create the possibility for desirable states of the world and can cause undesirable states to cease to exist.
Abstract: Many ecosystems appear subject to regime shifts—abrupt changes from one state to another after crossing a threshold or tipping point. Thresholds and their associated stability landscapes are determined within a coupled socioeconomic–ecological system (SES) where human choices, including those of managers, are feedback responses. Prior work has made one of two assumptions about managers: that they face no institutional constraints, in which case the SES may be managed to be fairly robust to shocks and tipping points are of little importance, or that managers are rigidly constrained with no flexibility to adapt, in which case the inferred thresholds may poorly reflect actual managerial flexibility. We model a multidimensional SES to investigate how alternative institutions affect SES stability landscapes and alter tipping points. With institutionally dependent human feedbacks, the stability landscape depends on institutional arrangements. Strong institutions that account for feedback responses create the possibility for desirable states of the world and can cause undesirable states to cease to exist. Intermediate institutions interact with ecological relationships to determine the existence and nature of tipping points. Finally, weak institutions can eliminate tipping points so that only undesirable states of the world remain.

156 citations