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4.13 Ecosystem assessment
Ecosystem Assessment
Mohamed Tawfic Ahmed
Suez Canal University
  1. Introduction
    Millions of species populate Earth. The vast majority gain energy to support their metabolism either directly from the sun, in the case of plants, or, in the case of animals and microbes, from other organisms through feeding on plants, predation, parasitism, or decomposition.

    In the pursuit of life and through their capacity to reproduce, organisms use energy, water, and nutrients. As organisms interact with each other and their physical environment, they produce, acquire, or decompose biomass and the carbon-based or organic compounds associated with it. They also move minerals from the water, sediment, and soil into and among organisms, and back again into the physical environment. Terrestrial plants also transport water from the soil into the atmosphere. In performing these functions, they provide materials to humans in the form of food, fiber, and building materials and they contribute to the regulation of soil, air, and water quality.

    Photo: Wildlife in Masai Mara, by Peter Prokosch GRID-Arendal photos

    These relationships sound simple in general outline, but they are in fact enormously complex, since each species has unique requirements for life and each species interacts with both the physical and the biological environment. Recent perturbations, driven principally by human activities, have added even greater complexity by changing, to a large degree, the nature of those ecosystems. Hence, an ecosystem is made of a complex web of biotic and abiotic components, and the nature of these webs would vary depending on the nature of the ecosystem, weather and arid ecosystem, marine ecosystem, or otherwise.

    Although the notion of an ecosystem is ancient, ecosystems first became a unit of study less than a century ago, when Arthur Tansley provided an initial scientific conceptualization in 1935 (Tansley 1935) and Raymond Lindeman did the first quantitative study in an ecosystem context in the early 1940s (Lindeman 1942). The first textbook built on the ecosystem concept, written by Eugene Odum, was published in 1953 (Odum 1953). Thus the ecosystem concept, so central to understanding the nature of life on Earth, is actually a relatively new research and management approach.

  1. Humans and Ecosystems
    Human well-being and progress toward sustainable development are vitally depend upon Earth's ecosystems. The ways in which ecosystems are affected by human activities will have consequences for the supply of ecosystem services - including food, fresh water, fuelwood, and fiber-and for the prevalence of diseases, the frequency and magnitude floods and droughts, and local as well as global climate. Ecosystems also provide spiritual, recreational, educational, and other nonmaterial benefits to people.

    Changes in availability of all these ecosystem services can profoundly affect aspects of human well-being-ranging from the rate of economic growth and health and livelihood security to the prevalence and persistence of poverty.

    Human demands for ecosystem services are growing rapidly. At the same time, humans are altering the capability of ecosystems to continue to provide many of these services. Management of this relationship is required to enhance the contribution of ecosystems to human well-being without affecting their long-term capacity to provide services.

    All economies depend on ecosystem services. The production and manufacture industrial wood products in the early 1990s contributed on the order of $400 billion to the global economy (Matthews et al. 2000). The world's fisheries contributed $55 billion in export value in 2000 (FAO2000). Ecosystem services are particularly important to the economies of low-income developing countries. Between 1996 and 1998, for example, agriculture represented nearly one fourth of the total gross domestic product of low-income countries (Wood et al. 2000).

    Yet many ecosystem services are largely unrecognized in their global importance or in the pivotal role they play in meeting needs in particular countries and regions (Daily et al. 2000). For example, terrestrial and ocean ecosystems provide a tremendous service by absorbing nearly 60 percent of the carbon that is now emitted to the atmosphere from human activities (IPCC 2000), thereby slowing the rate of global climate change. A number of cities-including New York and Portland, Oregon, in the United States, Caracas in Venezuela, reduce water treatment costs by investing in the protection of the natural water quality regulation provided by well-managed ecosystems (Reid 2001).The contribution of pollination to the worldwide production of 30 major fruit, vegetable, and tree crops is estimated to be approximately $54 billion a year (Kenmore and Krell 1998). Even in urban centers, ecosystems contribute significantly to well-being, both aesthetically and economically: Chicago's trees remove more than 5,000 tons of pollutants a year from the atmosphere (Nowak 1994).

    Ecosystem goods and services are defined as a society's "natural capital"-its living and nonliving resources-is a key determinant of its well-being. The full wealth of a nation can be evaluated only with due consideration to all forms of capital: manufactured, human, social, and natural.
  1. Human Demands
    Current demands for ecosystem services are growing rapidly and often already outstrip capacity. Between 1993 and 2020, world demand for rice, wheat, and maize is projected to increase by some 40 percent and livestock production by more than 60 percent (Pinstrup-Andersen et al. 1997). Humans now withdraw about 20 percent of the base flow of theworld's rivers, and during the past century withdrawals grew twice as fast as world population (Shiklomanov 1997; WHO 1997). By 2020, world use of industrial roundwood could be anywhere from 23 to 55 percent over 1998 consumption levels (Brooks et al. 1996).

    Continuing degradation of the world's ecosystems is neither inevitable nor justified. Many instruments now exist that can aid in the management of human demand for ecosystem services and of impacts of human activities on ecosystems. Recent progress in cost-effective technologies, policies, and regulation can contribute to management systems that can reduce and eventually reverse many of today's problems. Investments in improved management of ecosystem services tend to be highly leveraged strategies for sustainable development. Like the benefits of increased education or improved governance, the protection, restoration, and enhancement of ecosystem services tend to have multiple and synergistic benefits. For example, technology allows partial substitution of the ecosystem service of water purification through the construction of water treatment facilities. But by protecting the watershed to enable the ecosystem to provide this service instead, a variety of other benefits can often be obtained-such as the maintenance of fisheries, reduction of flood risks, and protection of recreational and amenity values.
  1. Sustainable Development
    It has been generally agreed that earth with its finite resources can only support a finite number of inhabitants. Continued expansion of the human population is going to lead to severe environmental degradation because of resource depletion and pollution. As a result, humanity must find a way to stop runaway population growth. The problem of human population growth has no technical or scientific solution. The solution, lies in a change of human morals. To accomplish this change, Governments must act to modify the behavior of their citizens in terms of reproduction. In other words, the human freedom to reproduced must be controlled.

    Human nature may be responsible for our over-exploitation of nature. Humans generally use resources with short-term advantage in mind. Users of any communal resource tend to ignore the fact that the resource is also required by others. Such attitude was one of the main drivers for the newly concept of sustainable use of natural resources.

    Sustainable development is the development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs. Sustainable development evolved as a broad policy priority over the last two decades. The world community renewed its commitments to this policy and emphasizes its priority in the second World summit on sustainable development held in Johannesburg last year.

    Sustainable development brought new requirements for ecosystem assessment, including among others; recognizing the links between environmental conditions and human activities; highlighting the need for long-term perspectives; explicitly recognizing uncertainties and emphasizing adaptive management; considering equity both within and between generations; and engaging the participation of all sectors of society in the decision-making process.
  1. Human Modification of Ecosystem Productivity
    Humans have altered the productivity of the Earth's ecosystems through a variety of direct and indirect means. Currently, 10 to 15 % of the Earth's land surface is occupied by cultivated crops or built structures of human settlement. Both of these changes in land-use have resulted in an almost complete removal of the natural species once occupying this area of Earth's surface. This type of land-use change also represents one of the primary forces causing the loss of biodiversity from the Earth. An additional 6 to 8 % of the Earth's surface is being used to support grazing livestock. Grazers modify ecosystems by reducing their productivity through consumption. Livestock can also encourage the invasion and dominance of species that favor the grazing process.

    Indirectly, humans are altering the productivity of ecosystems by the modification of the Earth's biogeochemical cycles. Atmospheric carbon dioxide has increased in concentration from 280 ppm (parts per million) before the industrial revolution (prior to 1700) to today's value of about 362 ppm. This increase has been mainly due to human induced burning of fossil fuels and land-use change. Scientists predict that the concentration of carbon dioxide will continue to increase in our atmosphere until the year 2100. At this time, the level of carbon dioxide in the Earth's atmosphere may be between 450 to 600 ppm. Higher concentrations of carbon dioxide in the atmosphere can influence plant productivity in two ways. In general, photosynthesis becomes more efficient in plants at higher concentrations of carbon dioxide. For many species of plants an increase in photosynthetic efficiency will lead to increases in productivity. Higher concentrations of atmospheric carbon dioxide will also cause climate change through global warming. In most cases, higher temperatures should increase productivity where water is not a limiting factor to growth. Should water becomes less available to plants, because of enhanced evapotranspiration, plant productivity will decrease because of drought.

    Humans are also altering the biogeochemical cycling of nitrogen. Nitrogen is commonly the most limiting soil nutrient for plant growth. Naturally, nitrogen is supplied to plants from a vast atmospheric store by a variety of fixing processes. Humans have increased the supply of fixed nitrogen available in natural ecosystem through the use of fertilizers, cultivation of leguminous crops and indirectly by way of burning of fossil fuels. Initially, higher concentrations of nitrogen increase plant growth. However, if levels get too high, a condition known as nitrogen saturation, productivity can be reduced because of chemical changes to the soil.
  1. Carrying Capacity
    The concept of sustainability is directly related to carrying capacity.
    Carrying capacity can be defined as "the maximal population size of a given species that an area can support without reducing its ability to support the same species in the future." Many scientists and resource managers believe that present levels of human resource consumption far exceeded the carrying capacity of these resources. Some individuals believe that advances in technology will lower the impact of per capita consumption on the environment.
  1. Resilience
    Ecosystem resilience describes the capacity of an ecosystem to cope with disturbances, such as storms, fire and pollution, without shifting into a qualitatively different state. A resilient ecosystem has the capacity to withstand shocks and surprises and, if damaged, to rebuild itself. In a resilient ecosystem, the process of rebuilding after disturbance promotes renewal and innovation. Without resilience, ecosystems become vulnerable to the effects of disturbance that previously could be absorbed.

    Clear lakes can suddenly turn into murky, oxygen-depleted pools, grasslands into shrub-deserts, and coral reefs into algae covered rubble. The new state may not only be biologically and economically impoverished, but also irreversible.

    Gradual loss of resilience can lead to unexpected collapse There is increasing evidence that ecosystems seldom respond to gradual change in a gradual way. Lakes often appear to be unaffected by increased nutrient concentrations until a critical threshold is passed and the water shifts abruptly from clear to turbid. Submerged plants suddenly disappear and animal and plant diversity is reduced - an undesired state from both a biological and economic point of view. Substantially lower nutrient levels than those at which the collapse of the vegetation occurred are required to restore the system. The economic and social intervention involved in a restoration is complex and expensive, and sometimes even impossible.

    Studies of rangelands, forests, and oceans also show that human-induced loss of resilience can make an ecosystem vulnerable to random events like storms or fi re that the system could earlier cope with. An ecosystem with low resilience can often seem to be unaffected and continue to generate resources and ecosystem services until a disturbance causes it to exceed a critical threshold. Even a minor disturbance can cause a shift to a less desirable state that is difficult, expensive, or even impossible to reverse.

    Biodiversity plays a crucial role in ecosystem resilience by spreading risks, providing "insurance", and making it possible for ecosystems to reorganise after disturbance. Ecosystems seem to be particularly resilient if there are many species performing the same essential function (such as photosynthesis or decomposition) and if species within such "functional groups" respond in different ways to disturbances. Then, species can replace or compensate for each other in times of disturbance.

    When humans reduce biodiversity or favour monocultures, ecosystems tend to become vulnerable.
    In a coral reef, several species graze on algae. Due to overfishing in the Caribbean, one of the species, a sea urchin, became a dominant grazer throughout the region. However, a disease hit the sea urchins and they were decreased drastically. This resulted in a shift from a coral to an algae-dominated state resulting in reduced biodiversity and a decreased capacity to support human society. A diversified decision-making structure is critical to building resilience in social-ecological systems. This implies that ecosystem management is shared by subunits of various sizes and scales, from national governments to local villages. It allows for testing of rules and policies over the short, medium and long term as well as at local, national and international levels. It enables social institutions to better match ecological processes
  1. The concept of Ecosystem Assessment
    The term "Assessment" has been used to mean a scientific study of a problem of practical importance, conducted to enable or at least help someone to make a decision about what actions should be taken to achieve the best effects. Normally, there will be alternative decision options with different consequences to different stakeholders. Another definition considers an assessment "a social process that uses published peer-reviewed material, and other forms of knowledge/ publications to bring the findings of science to bear on the needs of decision-makers" (UNEP, IISD 1999).

    Assessments fall somewhere in between pure scientific research (information generation) and the use of information by policy- and decision-makers. They can function as bridges between the realm of knowledge generation and the realm of knowledge application, i.e., action, or between science and policy (Moser 1998). Any assessment usually entails collecting and analyzing existing knowledge, however some new or additional research may be required to fill in gaps.
    The term "Ecosystem" indicates that the assessment is related to some aspect of the environment or natural or ecological resources. This includes both natural components of the environment such as forests, biodiversity, water, land, coastal and marine environment, or atmosphere, as well as human activity components such as agricultural, urbanization, energy, industry, transport, tourism, trade, and so on.

    Ecosystem assessment is thus considered an organized information gathering process to assess the condition of our environment, the pressures exerted on it (human and natural) and the way we respond. Through environmental assessment, we can identify and understand the effects of nature and human actions on the biophysical and socio-economic environments to be affected. In other words, it is a process, which assist us measure our environmental performance toward sustainability. It is a key planning and decision-making tool (CEAA, 1994).
  1. Policies and Strategies in Ecosystem Assessment
    Policies and strategies are significant components of an ecosystem assessment The reason for this is that the intentional or unintentional consequences of policies are often spread over space, time, and cross over sectors of the economy as well as environmental media. While the consequences of policies can be incremental and cumulative, they may also represent root causes of environmental problems. A good example of such case can be drawn from food security policy that evolved in some developing countries during the seventies and the eighties of the last century where intensification of agricultural production resulted in salinization of irrigated soils, deterioration of marginal lands, rangelands, and degradation of groundwater resources. It can be seen here that such a policy had not resulted in environmental impacts only but its consequences had spread over the years with social and economic impacts.

    Ecosystem assessment can be looked at as an interdisciplinary and participatory process that combines, interprets and communicates knowledge from different scientific disciplines for better understanding of complex phenomena. In other words, it is the process of producing and communicating policy-relevant information on key interactions between the natural environment and society. Figure 1 illustrates the linkages between ecosystem and society needs.

    In simple words, Ecosystem Assessments provide information to help decision makers understand the state of environmental resources and relate the findings to appropriate management decisions. It is a tool that can help managers and decision makers to:
    • solve environmental planning and management problems
    • improve their understanding of environmental conditions;
    • design protective or remedial strategies. (EEA 1998).
  1. Ecosystem Indicators
    There is a growing interest from governments, local as well as international communities in environmental assessment and monitoring of condition of environment, identify trends of change, measuring environmental performance and evaluating environmental progress toward sustainable development to see how we are doing. Environmental indicators provide us the necessary tools to track and chart such a progress. Indicators help us understand what we are doing, where we are, which way we are going, and whether we are going in the right direction. It is a tool that enables us to be alert of evolving problems and helps us recognize what needs to be done to correct these problems.

    In scientific terms, an indicator is defined as a parameter or a value derived from parameters, which provides information about a phenomenon. The indicator has a significance that extends beyond the properties directly associated with the parameter value (OECD 1993).
    Indicators have two major functions (OECD, 1994):
    - Reduce the number of measurements and parameters, which normally would be required to give an exact presentation of a situation;
    - Simplify the communication process by which the results of measurement are provided to the user.

    One of the possible models to describe the interactions between society and environment is the pressure-state-response (PSR) model or the more detailed alternative; pressure-state-impact-response (PSIR) model. These three elements (PSR) are the basic components of the pressure-state-response framework underlying the integrated environmental assessment approach.
  1. Pressures:
    Pressures are often classified into root causes and driving forces such as population growth, industrial expansions, consumption or poverty. The pressures on the environment are often considered from a policy perspective as the starting point for tackling environmental issues. Information on pressures tends to be the most readily available since they are derived from socio-economic databases. In this context, pressures are those human activities that exert stresses or pressures on the environment and bring about environmental change (i.e. population growth, use of pesticides, industrial releases into water, etc…). They can be grouped into four basic types:

    1. Pressures resulted from societal developments (demography, technology, migrations, etc.).
    2. Pressures resulted from unintended consequences of policies (i.e. food security).
    3. Pressures resulted from natural processes such as storms, droughts.
    4. Pressures resulted from environmental policies that exert positive pressures on environmental change.

    State: Refers to the condition of the environment resulting from the pressures. It is the quality and quantity of environmental and natural resources. (i.e. forest area, burnt area, level of air pollution, etc…). In this regard, considering change in (positive or negative, or unchanged) state of environment over time is termed trend.

    Impact: The observed consequences of the status quo, such as human health effects or damages to vegetation or economy. For example increased land degradation may lead to decreased food production, increased fertilization use, siltation of waterways, etc. In terms of indicators, it is sometimes difficult to distinguish between state and impact.

    Response: Refers to societal actions adopted to ease or avoid harmful environmental impacts, correct environmental damage, or conserve natural resources. Responses may include regulatory action, environmental or research expenditures, public opinion and consumer preferences, changes in management strategies, and providing environmental information.

    Driving forces: Term refers to "socio-economic or socio-cultural factors driving activities that increase or mitigate the pressure on the environment." Some driving forces are obvious, like for instance development of industry, agriculture, tourism, transport or construction. Such developments are driven by underlying forces such as population growth, prosperity level, attitudes within the society, or changes in technology. Traffic intensity is a driving force whereas total Nox emissions and share of automobile in it is a pressure. In this case concentrations of gas pollutants in urban air is state/impact (air quality degradation) whereas emission control test is a response.
  1. Impact of Pollutants on Ecosystems
    Pollutant impact on ecosystem is an urgent and international issue, since there is an ever-increasing number of examples of environmental disturbance, likely to affect the biota and humans, by both natural and anthropogenic stress. Important stressors include toxic industrial chemical contaminants, increased UV-radiation, nutrient enhancement or deprivation, hypoxia, habitat disturbance and pathogen-induced disease. In fact, environmental disturbance will frequently comprise various combinations of such stresses. Furthermore, it is increasingly recognised that assessment of the impact of environmental disturbance on organisms requires understanding of stress effects throughout the hierarchy of biological organisation, from the molecular and cellular to the organism and population levels, as well as the community and ecosystem level. In the past, damage to the environment has largely been identified retrospectively and in response to acute events such as major disasters (e.g., industrial accidents like Seveso and Bhopal; and oil spills (Amoco Cadiz & Exxon Valdez) and chemical pollution of the Great Lakes). Generally, these have been measured in terms of human health impacts and visible changes resulting from the loss of particular populations or communities. However, long term and chronic exposure to environmental stress, including chemical pollutants or other anthropogenic factors, will seldom result in rapid and catastrophic change. Rather, the impact will be gradual, subtle and frequently difficult to disentangle from the process and effects of natural environmental change. This latter problem has been a major stumbling block in assessing environmental impact since such investigations began, mainly in the 1960s.

    The major issues of concern include the role of "Industry" as a major source of pollution; the fact that pollution does not respect national boundaries; the loss of living resources and biodiversity; damage to human health; and support for sustainable financing and banking in order to support developing economies. The environmental objectives of sustainable industrial development include the sound management of natural resources, effective transfer of environmentally sound technologies in order to reduce, reuse and recycle waste, investment promotion for sustainable industry, environmental monitoring and control of investments for environmental industry projects.

    Environmental Stress can be caused by a number of factors including:- natural forces such as sea level rise, climate change and soil erosion; poorly planned development, such as haphazard urbanisation and industrialisation; depletion of resources through over-fishing, deforestation and poor use of agricultural land; unregulated discharges of municipal sewage and industrial waste; and illegal practices, such as disposal of dangerous toxic wastes.
  1. Ecosystem Management Tools
    A number of environmental management tools have been developed to safeguard ecosystem from various types of perturbations. These tool are playing a key role in maintaining the quality of ecosystem integrity. Some of the most important tools used are:
  1. Environmental Impact Assessment EIA
    The most common conception of EIA is as a planning tool that forecast and evaluate the impacts of a proposed project and its alternatives on the ecosystem. As a planning tool, EIA it illuminates environmental issues to be considered in making decisions.

    EIA was developed in the USA in the 1960s but eventually spread to almost all countries all over the world. EIA is a planning process made of several steps meant to ensure that all development work would heed ecosystem integrity and safety.
  1. Strategic Environmental Assessment SEA
    SEA has been described as the application of environmental impact assessment at the level of policies, plans and programmes. More specifically, SEA can be defined as the formalized systemic and comprehensive process of evaluating the environmental impacts of a policy, plan or programme and its alternatives including the preparation of a written report of the finding of that evaluation and using the findings in a publicly accounted decision making.
  1. Life Cycle Analysis LCA
    The main goal of life cycle analysis is to support decision making and facilitates improvements in production systems or labelling. With LCA the outcome decision alternatives are assessed with respect to inputs of resoures such as material, energy and land. And outputs of chemical emissions and physical interventions into the environment. Such inputs and outputs are quantified with respect to their potential for affecting ecosystem quality, and resources availability. Land use and its impact are also taken into account in LCA. The reason for this is that environmental consequences of land use can be as severe as those of climate change. The Earth 's land areas are dominated by human usage. In many of the industrialized countries a large proportion of land is used for forestry, agriculture, cities and infrastructure. A small area is remaining and occupied by natural resources. Irreversible consequences of such intensive use of land include soil degradation and erosion and shifts in groundwater availability.
  1. Ecological Risk Assessment
    A key aim of environmental science is to derive robust, practical and relatively low cost procedures for assessing risk to the health of the biosphere and to use this capability to predict the likely consequences of exposure to potentially harmful toxic pollutants. Until relatively recently, risk assessment procedures have been oriented towards protecting human health. Now, it is widely acknowledged that such procedures must also ensure that complex biotic communities in natural ecosystems are protected if the quality of the environment in which we live is to be maintained. Environmental risk assessments are currently based on a suite of information derived from studies on the physical chemical characteristics of compounds (the QSAR approach), and from laboratory-based toxicity tests.

    Although these procedures constitute a low cost, pragmatic means of ranking the toxicity of potentially hazardous chemicals, they do not directly evaluate the sublethal toxicity, or other adverse effects (e.g., disturbance of ecological relationships) on organisms exposed to complex mixtures of pollutants in the highly fluctuating conditions that prevail in the environment.

    Ecological risk assessment is a new field that arose in the 1980s. Regulators needed something equivalent to human health risk assessments for use in making environmental decisions.
    The ecological risk paradigm developed is based on the paradigm for human health risk assessment but incorporates the greater complexity of ecological systems. In particular it recognizes that ecological risk assessments must identify endpoints from among the array of properties of various populations, communities, and ecosystems. It recognizes that the scale and structure of the receiving environment are critical to assessment of ecological risks. It also recognizes the ecological risks are likely to involve indirect effects and changes in habitats as well as the direct toxic effects.

    Step 1 - Identification of the problem. This is the process of identifying the nature of the problem and developing a plan for the remainder of the risk assessment based on this information. It defines the objectives and scope of, and provides the foundation for, the risk assessment. In the case of a chemical impact, it would include obtaining and integrating information on the characteristics (for example, properties, known toxicity) and source of the chemical, what is likely to be affected, and how is it likely to be affected, and importantly, what is to be protected.

    Step 2 - Identification of the adverse effects. This step evaluates the likely extent of adverse change or impact on the wetland. Such data should preferably be derived from field studies, as field data are more appropriate for assessments of multiple impacts, such as occur on many wetlands. Depending on the extent of adverse change and available resources, such studies can range from quantitative field experiments to qualitative observational studies. For chemical impacts, on-site ecotoxicological bioassays constitute appropriate approaches, whereas for changes caused by weeds or feral animals, on-site observation and mapping may be all that is required.

    Step 3 - Identification of the extent of the problem. This step estimates the likely extent of the problem on the wetland of concern by using information gathered about its behaviour and extent of occurrence elsewhere. In the case of a chemical impact, this includes information on processes such as transport, dilution, partitioning, persistence, degradation, and transformation, in addition to general chemical properties and data on rates of chemical input into the environment. In the case of an invasive weed, it might include detailed information on its entry into an ecosystem, rate of spread and habitat preferences. While field surveys most likely represent the ideal approach, use of historical records, simulation modeling, and field and/or laboratory experimental studies all represent alternative or complementary methods of characterising the extent of the problem.

    Step 4 - Identification of the risk. This involves integration of the results from the assessment of the likely effects with those from the assessment of the likely extent of the problem, in order to estimate the likely level of adverse ecological change on the wetland. A range of techniques exist for estimating risks, often depending on the type and quality of the likely effects and their extent. A potentially useful technique for characterising risks in wetlands is via a GIS-based framework, whereby the results of the various assessments are overlaid onto a map of the region of interest in order to link effects to impact. In addition to estimating risks, such an approach would also serve to focus future assessments and/or monitoring on identified problem areas.

    Step 5 - Risk management and reduction. This is the final decision-making process and uses the information obtained from the assessment processes described above, and it attempts to minimize the risks without compromising other societal, community or environmental values. In the context of the Ramsar Convention, risk management must also consider the concept of wise use and the potential effects of management decisions on this. The result of the risk assessment is not the only factor that risk management considers; it also takes into account political, social, economic, and engineering/ technical factors, and the respective benefits and limitations of each risk-reducing action. It is a multidisciplinary task requiring communication between site managers and experts in relevant disciplines.

    Step 6 - Monitoring. Monitoring is the last step in the risk assessment process and should be undertaken to verify the effectiveness of the risk management decisions. It should incorporate components that function as a reliable early warning system, detecting the failure or poor performance of risk management decisions prior to serious environmental harm occurring. The risk assessment will be of little value if effective monitoring is not undertaken. The choice of endpoints to measure in the monitoring process is critical. Further, a GIS-based approach will most likely be a useful technique for wetland risk assessment, as it incorporates a spatial dimension that is useful for monitoring adverse impacts on wetlands.
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The Greenhouse effect, Climate Change and the road to sustainability
1. 1 Greenhouse effect
2. 2 Science
3. 3 Mitigation
4. 4 Impacts
5. 5 Solutions?