Gleissman, S. Agroecology: Ecological Processes in Sustainable Agriculture. Odum, E. Sinauer Associates, Inc. Seybold, C. Herrick and J. Soil resilience: A fundamental component of soil quality. Soil Science This means that it is capable of sustaining itself and reproducing.
Sustainable ecosystems have biodiversity. Ecosystem destruction is already happening. This is due to ocean acidification, water pollution and illegal fishing.
If all the corals go, what will happen to our marine life? More: Threats on Coral Reefs. Deforestation is caused by Illegal logging and human need and progress. More than 4. How many species have become extinct due to this?
How many homes have been destroyed? Habitat loss is endangering our animal species. Even our apex predators are being affected — the lion, tiger, polar bear and even the majestic mountain gorillas are all being threatened by habitat loss.
Humans destroy ecosystems. Our lifestyle creates pollution and we overuse our natural resources. We build roads, hunt animals, cut down trees destroying forests and just litter the planet like crazy. We waste resources that are not infinite and will soon run out, if we continue our practice.
To date, we have extracted approximately 23 billion tons of resources from the Earth. Our natural ecosystems are finding it hard to cope with the different pressures and are unable to adjust. If we continue depleting resources and destroying our environment, soon it will be too late for them to recover, even with our help. More: Environmental Degradation Facts. Like I mentioned, everything relies on everything else around it. Our planet is alive and interconnected and we are part of that web.
However, in some cases the impact on management of a potential shift could work in the opposite direction. The ability of a social-ecological system to recover from shocks such as a hurricane or an oil spill is improved by having highly functional institutions and a high degree of social cohesion. Disasters that inflict large-scale and widespread damage put ecosystems and human communities under great stress. Help from outside the stricken area, such as from the federal government, is often essential to provision of relief in the immediate aftermath of a disaster.
But long-term recovery depends in large part on the resources and resourcefulness of the local community Picou and Martin, Good governance also aids in assessing potential threats and long-term stresses and in bringing about changes in management or behavior to address them Folke et al. Trust in institutions is a key variable in attaining cooperation to make changes, especially if the change requires at least some short-term sacrifice.
Lack of good governance or social capital can lead to social, economic, or ecological decline and a downward spiral in environmental conditions and human well-being Folke et al. Management itself can enhance system resilience if it creates responses to current conditions in ways that lessen the impacts of disturbances. The effectiveness of management can be enhanced by improving understanding of system dynamics, reducing uncertainty, and developing better early warning signals of approaches to thresholds.
Conserving biodiversity or increasing. The emphasis on properties to promote general resilience is important given the inability to predict the type, timing, scale, and interaction of future disturbances.
Although resilience management can result in many benefits, translation of resilience theory into improved agency decision making for ecosystem service management will be difficult. Because resilience management represents a significant change from current management priorities or decision-making processes, congressional authorization in the form of new or amended laws Ruhl, may be necessary to make it part of the process. A fundamental principle of federal administrative law, rooted in Article I of the U.
Constitution, is that agencies cannot act in ways that exceed the statutory authority Congress has given to them Doremus, Whether resilience management is consistent with current resource management laws depends upon current statutory authority and the details of resilience management. For example, an agency committed to incorporating resilience management would need to. In many ways, the challenges that agencies face in resilience management are similar to those in adaptive management.
Some federal agencies, notably the U. Forest Service, the U. Fish and Wildlife Service, the Bureau of Reclamation, and the National Oceanic and Atmospheric Administration, have begun to recognize the importance of resilience management and to incorporate it into their broader policy objectives Benson and Garmestani, Order No.
Unlike terrestrial systems, the oceans are entirely public and are not interspersed with private holdings. The federal government thus has more freedom both to set and adjust regulations. In federal waters outside of state jurisdiction, federal agencies could manage all resource use holistically to attain broad systemic goals. Finally, the laws pertaining to resource use in the oceans have traditionally been designed to function under changing environmental conditions and substantial uncertainty.
The Magnuson-Stevens Fishery Conservation and Management Act MSA requires regular input of scientific information and annual consideration of management measures, which enable decision makers to respond to environmentally driven stock fluctuations Carlarne and Eagle, Still, resilience management in the GoM ecosystem faces challenges. The United States lacks a legal tradition of managing complex systems as multiple, interacting systems.
Congress has traditionally written laws that address resources individually; thus, the MSA governs the use of fisheries, the Outer Continental Shelf Lands Act regulates oil and gas and mineral use, and so on Eagle, The resource-by-resource approach is less amenable to resilience management than is a place-based approach.
That approach, in which a single agency has jurisdiction over most resource use within a single place e. In addition, the GoM ecosystem is affected by actions taken on land that influence nutrient and sediment inputs and are controlled by agricultural and other policies Rabalais et al.
Finally, although there are no private property interests in federal Gulf waters, there are private interest groups that would likely oppose significant changes to the current system of resource management.
Because these groups have the incentives and resources to oppose change at all levels, a management shift would need to be accompanied by an explanation of why its benefits would outweigh the real or perceived costs Ruhl, Although the maintenance of resilient ecosystems has many benefits, including provision of a steady flow of ecosystem services, political, legislative, and institutional barriers may impede implementation of resilience management.
How might governments manage publicly owned resources in a way that minimizes disruption to the flow of ecosystem services during and after a disaster? One approach is to move away from the current legal approach to managing marine ecosystems and toward a set of laws that aim to manage distinct, defined areas of the sea for narrower, specific objectives.
Although the efficacy of these laws in achieving their stated objectives is debatable, it is clear that each law uses a single, science-based concept aimed at achieving a single goal with. Because of the substantial scientific uncertainty involved in estimating necessary numerical targets, such as optimum yield and potential biological removals, it might be possible to increase the resilience of marine ecosystems by diversifying management strategies and objectives on a geographical or stock-by-stock basis.
So, Congress could, for example, modify the MSA and the MMPA so that managers would be required to apply a range of strategies over a set of geographically defined management areas or over a set of distinct fish or mammal populations. Some areas or species could be managed using more conservative versions of the traditional optimum yield or potential biological removal tools, and some areas or species could be managed using entirely different approaches and with different ends in mind.
The theory underlying this diversification approach is based on well-accepted principles that economists use to guide investors in the business world. As Gordon Munro observed, fishery or ecosystem management is similar to other forms of capital management:.
Economists view capture fishery resources, as they do all natural resources, as a form of natural capital, assets that are capable of yielding a stream of economic returns broadly defined through time. Since fishery resources are capable of growth like forests, but unlike minerals , these resources—natural capital—can be managed on a sustained basis, essentially by skimming off the growth through harvesting. This also means that the resources can provide economic benefits to society indefinitely.
It means further that one can, within limits, engage in positive investment in the natural capital by harvesting less than the growth. Munro, , p. Designing and implementing a portfolio-based law for managing marine ecosystems such as the GoM is a challenging, but not impossible, task.
Conceptually, such laws offer one of the most promising approaches to enhancing system resilience and thereby reducing the impacts of future human-engineered or natural disasters on the people who rely on those systems. One option for facilitating resilience management is employment of a portfolio approach to designing the system of laws regulating use of the Gulf of Mexico.
Under a portfolio approach, different management goals and strategies would be applied to discrete geographic ocean and coastal areas.
Such an approach, as compared with an aspatial management strategy that tries to ensure that all similar systems provide equal amounts of all services, provides a buffer against uncertainties, including future large-scale disturbances. Implementation of this portfolio approach would require congressional action because a set of new statutes would be needed.
Following an oil spill or other disturbance to an ecosystem, a key management objective is ecosystem restoration. Ecosystem restoration after a disturbance and ecosystem resilience are closely linked. Systems with low resilience may recover slowly or switch to a different regime and fail to return to original conditions. In the case of the DWH oil spill, of particular interest is how well restoration efforts will work to recover ecosystems to pre-spill conditions, both in terms of restoring the provision of ecosystem services and increasing resilience to further disturbances and ongoing stresses.
Much has been written about the restoration of the Mississippi River Delta Boesch et al. Restoration efforts in the delta are taking place in the midst of long-term changes as well as periodic disturbances. Coastal wetlands in the delta have failed to maintain elevation relative to mean sea level because of an inadequate supply of sediment. This process has been disrupted by armoring levees to prevent flooding, damming tributaries in the river basin, dredging canals, and other alterations that reduce sediment delivery to the delta and alter its hydrology.
Since the s, the delta has lost more than 4, km 2 , an area nearly the size of Delaware Barras et al. The U. Army Corps of Engineers USACE identified 2, km 2 of marsh or open water in five planning units within the lower delta requiring some 5. Much less is known about restoration efforts in other types of ecosystems. It may be difficult or impossible to fully restore some ecosystems after disturbances.
Changes in landscape structure, loss of native species or invasion by exotics, changes in species dominance hierarchies, trophic interactions, and biogeochemical processes may prevent returns to pre-disturbance conditions. Moreover, restoration efforts can be altered by feedbacks among biotic and physical processes Ehrenfeld and Toth, ; Suding et al. Restoration in the absence of knowledge of these feedbacks may launch an ecosystem down an unpredictable trajectory.
Restoration of ecosystem services does not necessarily follow from restoration of the ecosystem structure or the return of a habitat to a former state. Zedler concluded that numerous variables, including landscape setting, habitat type, hydrological regime, soil properties, topography, nutrient supplies, disturbance regimes, invasive species, seed banks, and declining biodiversity, can constrain the restoration process in wetlands.
However, this predictive capability is precisely what we seek in an ecosystem services approach. There is no existing roadmap for restoring all ecosystem services and functions. Currently, the best we can hope to accomplish are a few practical goals.
A target for a coastal wetland might be restoration to an elevation that is more resilient and that raises productivity and its value as wildlife habitat, knowing that it may not be practical or even possible to restore its original species composition. Conceptually, an ecosystem might cross a threshold in transitioning from one ecological state to another, such that restoration to a previous state is impeded by biotic and abiotic barriers Figure 3.
Examples of biotic thresholds could be the invasion of an exotic species e. Examples of abiotic thresholds include saltwater intrusion into a freshwater wetland as a consequence of rising sea level. Whether recovery of ecosystem services or restoration of the ecosystem is the goal, the endpoints must be defined in terms of practical metrics.
Hypothesized thresholds, indicated by vertical bars, may prevent recovery from a more degraded state to a less degraded state. Restoration aimed at returning a system to pre-disturbance conditions is closely related to resilience. Systems that cross critical thresholds after a disturbance can be difficult to restore, and restoration in the absence of a detailed understanding of system dynamics may launch an ecosystem down an unpredictable trajectory.
Whether recovery of ecosystem services or restoration of the ecosystem is the goal, the endpoints must be defined in terms of practical metrics that can be monitored.
The definitions of engineering and ecological resilience provide a basis for designing measures of resilience. Engineering resilience is the speed of recovery or the decay rate of the perturbation. Engineering resilience can be quantified post hoc as the time required to return to a pre-disturbance state after an experimental or natural disturbance. In natural systems with sufficiently rapid recovery, such as the sessile biota of the rocky intertidal, monitoring of recolonization can be done after disturbance Conway-Cranos, One could also attempt to measure the speed of recovery of social-ecological systems after disturbances.
For example, how fast or complete is recovery within a community or an industry after a shock such as a hurricane or an oil spill? Engineering resilience can also be modeled with various degrees of mathematical sophistication DeAngelis, ; Neubert and Caswell, ; Pimm and Lawton, With a model of system dynamics, an estimate of engineering resilience may be simulated for various severity levels of disturbances.
Although straightforward in theory, measurement of engineering resilience presents at least three practical challenges. First, there is the question of what particular measures or metrics will be used.
Some system components or ecosystem services may recover more quickly than others. For example, species diversity may well return to a previous state at a different rate than does primary productivity, or not at all. Hence, quantifying resilience may be heavily influenced by the choice of what is measured. Second, measurements of the speed of return require accurate baselines of conditions prior to the disturbance.
Third, disturbances that differ in type or scale are likely to result in quantitatively or possibly qualitatively different degrees of responses relevant to resilience Carpenter et al. Systems may be highly resilient to some kinds of shocks but not others. Measurement of ecological resilience is a more complex matter. Social-ecological systems are often too complex to enable researchers to accurately model potential regime shifts or to have much confidence in simulation results.
However, attempts to capture critical indicators of ecological resilience have been made. Changes in other system properties, such as variance, spatial correlation, autocorrelation, and skewness, may also prove useful in detecting approach to critical thresholds Scheffer et al. But this field is quite new and does not yet have a body of well-established results to guide management or policy.
Other research has explored the concept of functional diversity Allen et al. These approaches require species-level ecological information about function and response. For some groups of organisms, such as birds, this information may be inferred from size and morphology Cumming and Child, When a system is well understood, it may be more straightforward to define appropriate metrics for ecosystem resilience. With respect to tidal wetlands, for example, it seems prudent to adopt practical metrics that are inclusive of numerous ecosystem services and overall ecosystem function.
Practical metrics with these characteristics would be 1 change in total wetland area by plant community type and 2 relative elevation relative to mean sea level. Similarly, critical components of the ecosystem service under study that can be used to measure resilience should be identified. The ability to do this links directly to the understanding of the ecological production functions associated with the service and links directly back to the understanding of ecosystem dynamics.
The measurement of resilience poses a number of conceptual and practical challenges. Measures of speed of recovery to pre-disturbance conditions engineering resilience depend on having good baseline data and may vary depending on what ecosystem service or system component is measured and what type and severity of disturbance is considered.
Measuring how likely a system is to cross a critical threshold and undergo a regime shift ecological resilience is a topic that is at the frontier of science. Consensus on practical measures that can be used to predict the location of critical thresholds or the probabilities of regime shifts does not yet exist. However, for specific systems, it may be possible to define a set of metrics that measure key conditions or processes linked to system dynamics that can predict the resilience of the system and the return of provision of ecosystem services.
Resilient ecosystems can lead to the resilience of specific ecosystem services. However, ecosystems typically generate multiple ecosystem services. Changes in ecosystem structure and function will generally not affect all ecosystem services in the same manner. Therefore, different services could have different outcomes after a disturbance.
As noted by Carpenter et al. If the system is viewed through the lens of ecosystem services, then there is a need to identify the most important services and how they may be affected by potential alternate states of the system.
For example, coastal marsh habitat of the GoM provides several significant services, two of which are storm surge protection and fishing opportunities, both recreational and commercial.
The quality of these services is directly linked to the structural condition of the marsh. Fragmented marsh,. In contrast, continuous or connected marsh provides higher quality storm surge protection, but it is not as good for recreational and commercial fishing Minello et al. The quality of each of these services is strongly connected to two alternate states of marsh habitat. Focusing on the resilience of a particular state of a habitat e.
As a society we would prefer having more of all ecosystem services, but given that only one condition can occur at one time, there will be tradeoffs between services. As the Gulf of Mexico recovers from the Deepwater Horizon oil spill, natural resource managers face the challenge of understanding the impacts of the spill and setting priorities for restoration work.
The full value of losses resulting from the spill cannot be captured, however, without consideration of changes in ecosystem services--the benefits delivered to society through natural processes. An Ecosystem Services Approach to Assessing the Impacts of the Deepwater Horizon Oil Spill in the Gulf of Mexico discusses the benefits and challenges associated with using an ecosystem services approach to damage assessment, describing potential impacts of response technologies, exploring the role of resilience, and offering suggestions for areas of future research.
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