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Classification of ecosystem functions, goods and services




Vocabulary

environment – окружающая среда

biodiversity – биоразнообразие

awareness – осведомленность, информированность

abundance – избыток, богатство

nutrients – питательные вещества, биогенные вещества

vegetation – растительная жизнь

pedogenesis - почвообразовательный процесс

Read the text and answer the questions:

 

1. What is ecology?

2. What is the difference between ecology and environment?

3. What is the role of ecologists?

4. What other sciences does ecology connected with?

5. What do you know about history and development of ecology?

 

 

Table 1 below provides an overview of the main functions, goods and services that can be attributed to natural ecosystems and their ecological structures and processes. The first column indicates a list of functions and the second column lists the ecological structures and processes underlying these functions. The third column provides a more detailed list with examples of specific goods and services derived from these functions (not exhaustive). In Table 1, only those goods and services are included that can be used on a sustainable basis, in order to maintain the ecosystem functions and associated ecosystem processes and structures. Given these restrictions, important non-renewable natural mineral resources like gold, iron, diamonds, and oil are excluded from this list. Furthermore, energy sources that cannot be attributed to a certain ecosystem type are excluded, e.g. wind and solar-energy. On the other hand, some non-ecosystem specific functions that can be used without (permanently) affecting the other functions, such as the use of natural waterways for transportation, is included. Also some mineral resources that are renewable within a time-frame of 100–1000 years, like sand on beaches provided by dead coral and shells, are included.

Since the use of one function may influence the availability of other functions, and their associated goods and services, the capacity of ecosystems to provide goods and services in a sustainable manner should be determined under complex systems conditions. The ecosystem processes and components described in the second column of Table 1 should, therefore, be used in dynamic modeling to make these interdependencies, and the implications for their valuation, more explicit. It should be realized that ecosystem processes and services do not always show a one-to-one correspondence: sometimes a single ecosystem service is the product of two or more processes, whereas in other cases a single process contributes to more than one service. For example, the function ‘gas regulation’ is based on biogeochemical processes (like carbon and oxygen cycling) which maintain a certain air quality but also influence the greenhouse effect and thereby climate regulating processes. Furthermore, analysis of ecosystem functions and services involves different scales, notably the physical scale of the ecosystem function itself, and the scale at which humans value the goods and services provided. It is not a necessary condition that the two correspond. When valuing ecosystem functions, these inter-linkages and scale issues should be made clear.

 

Table 1

Functions, goods and services of natural and semi-natural ecosystems

 

Functions Ecosystem processes Goods and services (examples)
Regulation Functions Maintenance of essential ecological process and life support systems  
Gas regulation Role of ecosystems in bio-geochemical cycles (e.g. CO2/O2 balance, ozone layer, etc.) UVb-protection by O3 (preventing disease); Maintenance of (good) air quality; Influence on climate
Climate regulation Influence of land cover and biol. Mediated processes (e.g. DMS-production) on climate Maintenance of a favorable climate (temperature., precipitation, etc), for example, human habitation, health, cultivation  
Disturbance prevention Influence of ecosystem structure on dampening environmental disturbances Storm protection (e.g. by coral reefs); Flood prevention (e.g. by wetlands and forests)
Water regulation Role of land cover in regulating runoff & river   Drainage and natural irrigation; Medium for transport
Water supply Filtering, retention and storage of fresh water   Provision of water for consumptive use (e.g. drinking, irrigation and industrial use)
Soil retention Role of vegetation root matrix and soil biota in soil retention Maintenance of arable land; Prevention of damage from erosion/siltation
Soil formation Weathering of rock, accumulation of organic Maintenance of productivity on arable land
Nutrient regulation Role of biota in storage and re-cycling of nutrients Maintenance of healthy soils and productive
Waste treatment Role of vegetation & biota in removal or breakdown of xenic nutrients and compounds Pollution control/detoxification; Filtering of dust particles; Abatement of noise pollution.

 

 

2.1. Regulation functions and related ecosystem ser v ices

 

Natural ecosystems play an essential role in the regulation and maintenance of ecological processes and life support systems on earth. The maintenance of the earth’s biosphere as humanity’s only life support system in an otherwise hostile cosmic environment depends on a balance between many ecological processes. Some of the most important processes include the transformation of energy, mainly from solar radiation, into biomass (primary productivity); storage and transfer of minerals and energy in food chains (secondary productivity); biogeochemical cycles (e.g. the cycling of nitrogen and other nutrients through the biosphere); mineralization of organic matter in soils and sediments; and regulation of the physical climate system. All these processes, in turn, are regulated by the interplay of abiotic factors (i.e. climate) with living organisms through evolution and control mechanisms. In order for humans to continue to benefit from these functions, we need to ensure the continued existence and integrity of these natural ecosystems and processes. Because of the indirect benefits of regulation functions, they are often not recognized until they are lost or disturbed, but they are nevertheless essential to human existence on earth.

 

2.1.1. Gas regulation

Life on earth exists within a narrow band of chemical balance in the atmosphere and oceans, and any alterations in that balance can have positive or negative impacts on natural as well as social and economic processes. The chemical composition of the atmosphere (and oceans) is maintained by bio-geochemical processes which, in turn, are influenced by many biotic and a-biotic components of natural ecosystems. Important examples are the influence of natural biota on processes that regulate the CO2/O2 balance, maintain the ozone-layer (O3), and regulate SO x levels. The main services provided by the gas regulation function are the maintenance of clean, breathable air, and the prevention of diseases (e.g. skin cancer), i.e. the general maintenance of a habitable planet. An important issue when trying to determine the service value from this ecosystem function is the scale at which the analysis is carried out. For example, the influence of 1 hectare of ocean, or forest, as a carbon-sink is difficult to measure. However, the cumulative effect of losing 50% of the earth forest-cover, or 60% of the coastal wetlands, and the reduction of algae-productivity in large parts of the oceans due to pollution, on the gas regulation function is considerable.

 

2.1.2. Climate regulation

Local weather and climate are determined by the complex interaction of regional and global circulation patterns with local topography, vegetation, albedo, as well as the configuration of, for example, lakes, rivers, and bays. Due to the greenhouse- properties of some atmospheric gases, gas regulation (see above) also plays an important role in this function, but reflectance properties of ecosystems are also important in determining weather conditions and climate at various scales.

The services provided by this function relate to the maintenance of a favorable climate, both at local and global scales, which in turn are important for, among others, human health, crop productivity, recreation and even cultural activities and identity.

 

2.1.3. Disturbance pre v ention

This function relates to the ability of ecosystems to ameliorate ‘natural’ hazards and disruptive natural events. For example, vegetative structure can alter potentially catastrophic effects of storms, floods and droughts through its storage capacity and surface resistance; coral reefs buffer waves and protect adjacent coastlines from storm damage. The services provided by this function relate to providing safety of human life and human constructions.

 

2.1.4. Water regulation

Water regulation deals with the influence of natural systems on the regulation of hydrological flows at the earth surface. This ecosystem function is distinct from disturbance regulation insofar as it refers to the maintenance of ‘normal’ conditions in a watershed and not the prevention of extreme hazardous events. Ecosystem services derived

from the water regulation function are, for example, maintenance of natural irrigation and drainage, buffering of extremes in discharge of rivers, regulation of channel flow, and provision of a medium for transportation. A regular distribution of water along the surface is, therefore, quite essential, since too little as well as too much runoff can present serious problems.

 

2.1.5. Water supply

This ecosystem function refers to the filtering, retention and storage of water in, mainly, streams, lakes and aquifers. The filtering-function is mainly performed by the vegetation cover and (soil) biota. The retention and storage capacity depends on topography and subsurface characteristics of the involved ecosystem. The water supply function also depends on the role of ecosystems in hydrologic cycles (see function No. 4), but focuses primarily on the storage capacity rather than the flow of water through the system. Ecosystem ser vices associated with water supply relate to the consumptive use of water (by households, agriculture, industry).

 

2.1.6. Soil retention

The soil retention function mainly depends on the structural aspects of ecosystems, especially vegetation cover and root system. Tree roots stabilize the soil and foliage intercepts rainfall thus preventing compaction and erosion of bare soil. Plants growing along shorelines and (submerged) vegetation in near-coastal areas contribute greatly to controlling erosion and facilitating sedimentation. The services provided by this function are very important to maintain agricultural productivity and prevent damage due to soil erosion (both from land slides and dust bowls).

 

2.1.7. Soil formation

Soil is formed through the disintegration of rock and gradually becomes fertile through the accretion of animal and plant organic matter and the release of minerals. Soil-formation usually is a very slow process; natural soils are generated at a rate of only a few centimeters per century and after erosion, soil formation (or regeneration) from bedrock takes 100–400 years per cm topsoil (Pimentel and Wilson, 1997). Ecosystem services derived from soil formation relate to the maintenance of crop productivity on cultivated lands and the integrity and functioning of natural ecosystems.

 

2.1.8. Nutrient cycling

Life on earth depends on the continuous (re)cycling of about 30–40 of the 90 chemical elements that occur in nature. In addition tocarbon (C), oxygen (O), and hydrogen (H) (which have been discussed in the gas-, climate- and water-regulation services) the most important nutrients are nitrogen (N), sulfur (S) and phosphorous (P). Other so-called macro-nutrients are calcium, magnesium, potassium, sodium and chlorine. Furthermore, a large number of so-called trace elements are needed to maintain life, including, for example, iron and zinc. The availability of these elements is often a limiting factor to the growth and occurrence of life forms and constant (re)cycling of these nutrients is, therefore, essential. Many structural and functional aspects of natural ecosystems facilitate nutrient cycling at local and global scales. For example, soil organisms decompose organic matter thereby releasing nutrients to both local plant growth, but also to the atmosphere; algae in coastal waters perform this same function. Also, migration (of birds, fish and mammals) plays an important role in the distribution of nutrients between ecosystems.

Ecosystem services derived from nutrient cycling are mainly related to the maintenance of ‘healthy’ and productive soils. Furthermore, nutrient cycling plays an important role in the gas-, climate- and water-regulation functions.

 

2.1.9. Waste treatment

To a limited extent, natural systems are able to store and recycle certain amounts of organic and inorganic human waste through dilution, assimilation and chemical re-composition. Forests, for example, filter dust particles from the air, and wetlands and other aquatic ecosystems can treat relatively large amounts of organic wastes from human activities acting as ‘free’ water purification plants.

 




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