Ecosystem Services

An ecosystem is a dynamic complex of living organisms (such as plant, animal and microorganism communities) and the non-living environment (such as air, water and mineral soil) interacting as a functional unit (MA 2005). Humans are an integral part of ecosystems.

Within an ecosystem, the living organisms are interacting with the non-living environment through the nutrient cycle, the water cycle, and energy flows (ODUM 1971). These interactions are strong among the components within a defined ecosystem and weak across its boundaries. An example of an interaction is the pollination of plants by a bee. The pollination is required so that the plant can reproduce and, in case of agricultural plants, develop fruits. Another example is the provision of habitat: rivers are a habitat for fish. Groundwater stored in the soil can also be used by plants (see also water sources and optimisation of water use in agriculture) or be exploited for different human uses (see also groundwater sources and water use). Humans, as part of the ecosystem, are more than any other living organism depending entirely on functioning ecosystem services. However, human activity has a major impact on the health of ecosystem and functioning ecosystem services (see also water pollution, soil degradation and availability and allocation of water).

Therefore, sustainable sanitation and water management is crucial for a more sustainable ecosystem management as illustrated in the following figure.

Ecosystem services are the benefits people obtain from ecosystems. The Millennium Ecosystem Assessment of the United Nations divides ecosystem services into four categories (MA 2005):

1. Provisioning services are the products obtained from ecosystems. Those are among others the production of food, timber, fibre and water.
2. Regulating services encompass benefits obtained from the regulation of ecosystem processes. Those are among others the control of climate, floods, wastes, water quality and disease. With regard to water and sanitation, the purification of water through the decomposition of organic waste introduced into inland waters as well as coastal and marine ecosystems is an important regulating service.
3. Cultural services describe among others spiritual and recreational benefits obtained from an ecosystem.
4. Supporting services are for example water cycles, nutrient cycles, photosynthesis, soil formation and crop pollination. These services are required to maintain the other three mentioned services.

Mankind is fundamentally dependent on the flow of ecosystem services (MA 2005). The impacts of human activities on ecosystems have increased rapidly in the last few decades due to growing demand for these services. While the majority thereof can be considered beneficial to human well-being today (for example the overexploitation of water for agricultural purposes), there is growing evidence of adverse effects (the lowering of groundwater levels and the resulting difficulty to secure water for crops in the future).Humans have especially enhanced production of three ecosystem services: crops, livestock and aquaculture (see also aquaculture for plants or animals) through expansion of the area devoted to their production, and through technological inputs. This has resulted in an unfavourable change in other services such as water regulation (ALCAMO et al. 2003). For instance, the expansion of agricultural production requires an increasing amount of water for irrigation. Approximately 60% of the ecosystem services evaluated in the Millennium Ecosystem Assessment are being degraded or used unsustainably (MA 2005).

Ecosystems are essential for human well-being through the provision of their above mentioned services. Harmful effects of ecosystem changes on human well-being can be direct or indirect. Direct effects occur through locally identifiable biological or ecological pathways. For example, building dams can increase mosquito-breeding and thus the transmission of malaria. Indirect effects have more complex causes through social, economic and political routes. These effects are not always as immediate as the direct effects; they may even take decades to unfold.

The harmful effects of ecosystem change do not evenly impact human populations. Usually, poorly resourced populations suffer the most. Especially poor rural populations rely disproportionally on the integrity and functions of local ecosystems and are likely to lack the means to import ecosystem services.

How well-being is expressed and experienced is strongly dependent on the context and the situation reflecting geography, ecology, age, gender and culture. Yet, some components of well-being are widely spread:

1. Security
2. Basic material for a good life
3. Health
4. Good social relations
5. Freedom in choice and action, which is enhanced by the previous four components

Shortages of ecosystem services effect human well-being as follows:

• Provisioning services: e.g. a shortage of the provision of freshwater and food has a damaging effect on human well-being.
• Regulating services: without regulating functions such as water purification (natural water purification) the varied populations of human and animal life are not possible. Changes to an ecosystem can thus affect human health and other components of human well-being.
• Cultural services: among others trees, scenic landscapes, rivers or lakes influence the aesthetic, recreational, educational, cultural and spiritual aspects of human experience. Changes to ecosystem services that lead to contamination, depletion and extinction have consequently negative effects on this human experience.
• Supporting services: constitute an indirect link to human well-being as they are essential in sustaining the three other ecosystem services.

Some ecosystem services can be partially substituted by using physical capital. For example, limited amount of clean water can be obtained by using water filters. Yet, substitution possibilities depend critically on the economic status. Local needs are also often overridden by outsiders’ demands.

Ecosystem change and human well-being has both present and future dimensions. While an overexploitation of ecosystems may temporarily increase material well-being and alleviate poverty this could prove unsustainable in the long-run. In order to solve today’s pressing problems, human populations are often tempted to deplete tomorrow’s ecological resource base, which can endanger future well-being or even survival.

Drivers affect ecosystem services and human well-being at different spatial and temporal scales: climate change may operate on a global or large regional spatial scale, political change at national or municipal scale. Sociocultural change typically occurs more slowly, while economic change is faster.

There are both direct as well as indirect drivers to ecosystem change. While direct drivers influence ecosystem services directly, indirect drivers alter one or more direct driver.

Five indirect driversof ecosystem change and their services exist:

1. Demographic drivers: Global population doubled in the past 40 years and exceeded 7 billion in 2012.
2. Economic drivers: Global economic activity has increased almost sevenfold between 1950 and 2000. With rising per capita income, the demand for ecosystem services grows. Taxes and subsidies are important indirect drivers. Many subsidies currently increase rates of resource consumption, e.g. subsidies to the agricultural sector, increased food production and, consequently, water consumption, as well as nutrient and pesticide release.
3. Socio-political drivers: include the quantity of public participation in decision-making, groups participating in public decision-making (see also decision making tools), mechanisms of dispute resolution and the role of the state relative to the private sector. These factors influence the institutional arrangements of ecosystem management and property rights over ecosystem services. There has been an increase in multilateral environmental agreements.
4. Cultural and religious drivers: cultural factors can influence consumption behaviour and values related to environmental stewardship.
5. Science and technology: the impact of science and technology on ecosystem services is the most apparent in the case of food production. Much of the increase in agricultural output over the last 40 years has come from an increase in yields per hectare rather than expansion of cultivated area. The negative impact of science and technology can be exemplified with advances in fishing technologies that have contributed to the depletion of marine fish stock.

Habitat change, overexploitation, invasive species, pollution and climate change are the most important direct drivers of change in ecosystems. For each ecosystem, other direct drivers may play an important role:

• For terrestrial ecosystems and their services: land cover change, mainly to cropland, and the application of new technologies. Both land cover changes and the management practices and technologies used on land may cause major changes in terrestrial ecosystem services. For marine ecosystems and their services: fishing, both in coastal areas and in open ocean has led to an overexploitation of commercial fish stocks.
• For freshwater ecosystems: modification of water regimes, invasive species and pollution, especially nutrient overloading. The introduction of invasive species is one reason for species extinction in freshwater. Nutrients such as phosphorus and nitrogen at high levels can cause eutrophication in water bodies and lead to high levels of nitrate in drinking water.
• For coastal ecosystems: change of coastal habitats, such as forests, wetlands and coral reefs, through coastal urban sprawl, resort and port development,aquaculture (see also aquaculture for plants or animals) and industrialisation.

As the human population grows, more people rely on wetland services, especially freshwater supply (provisioning service) and the processes that enable freshwater supply, especially natural water purification and aquifer recharge. Yet, the usage of wetland services is often unsustainable. The growth in human population increases particularly the demand for agriculture, industry and households (see also the water cycle or water use). Agriculture requires water for irrigation and increased fertiliser and pesticides usage what in turn leads to regional water scarcity and eutrophication of water bodies stressing the ecosystem services.

Summing up, while humans depend on ecosystems and the services they provide, many of these services are used in an unsustainable way. This has and will have harmful consequences for human well-being. Those that live in poor rural areas are often the first being affected by the lack of these services and its consequences. They are also the least able to acquire substitutes for ecosystem services. It is a major challenge to reverse degradation of ecosystems while meeting increasing demand for their services, but it is a challenge that can be met. Changes in policies, institutions and practices can mitigate some of the negative consequences of pressure on ecosystems, although the changes are large and currently not on the way.