The Azimuth Project
Ecosystem services (Rev #5, changes)

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Ecosystem services


Many of the world’s resources, e.g., clean water, are not fixed pools but are constantly being replenished by the behaviour of entities in the overall ecosystem. Likewise many “processes”, e.g., decomposition of wastes, rely on the actions of ecosystem entities. Ecosystem services is the study of how resources for human activities depend upon the general ecosystem and its constituents.


The United Nations 2004 Millennium Ecosystem Assessment (MA) (see references) created a set of definitions for broad types of ecosystem services:

  1. provisioning such as the production of food and water, e.g.,

    • food (including seafood and game), crops, wild foods, and spices

      food (including seafood and game), crops, wild foods, and spices

    • water


    • pharmaceuticals, biochemicals, and industrial products

      pharmaceuticals, biochemicals, and industrial products

    • energy (hydropower, biomass fuels)

      energy (hydropower, biomass fuels)

  2. regulating such as the control of climate and disease, e.g.,

    • carbon sequestration and climate regulation
    • waste decomposition and detoxification
    • purification of water and air
    • crop pollination
    • pest and disease control
  3. supporting such as nutrient cycles and crop pollination, e.g.,

  4. cultural such as spiritual and recreational benefits, e.g.,

    • cultural, intellectual and spiritual inspiration
    • recreational experiences (including ecotourism)
    • scientific discovery

Relationship between biodiversity and ecological services

It’s not immediately clear that large amounts of biodiversity (beyond the level of having a single species fulfilling a given ecosystem task) are necessary for the ecosystem services humanity depends on. However, it is believed that high biodiversity levels are required for a robust ecosystem which reliably provides ecosystem services. There are three major hypotheses for this:

  1. The redundancy hypothesis assumes that, whilst multiple species can play a given ecosystem role, as the number of providers of a given role decreases stress on the ecosystem increases and robustness decreases. Thus healthy natural ecosystems develop redundancy.

  2. The rivet hypothesis postulates that removing a species is analogous to removing a rivet from an aircraft wing: the first few rivets distribute their workload to other rivets with relatively little effect, but the susceptibility to further damage and overall risk increases non-linearly with the number of removed rivets.

  3. The portfolio effect postulates that, given a particular stressor or damage, different species will be affected in different ways, so that the damage to the total ecosystem is likely to be much less than if there was only one species in a given role.

In addition, there is the obvious issue that science has not identified all the subtle ecosystem services, let alone identified which species provide them. As such, maintaining the current level of biodiversity can be seen as precautionary.

Putting economic values on ecosystem services

One way of encouraging care with ecosystem biodiversity is to place economic values on the services they provide. This is inherently going to be a difficult and controversial process due both to the wide range of ecosystem services and the difficulty of placing a price on something which is currently taken for granted. However, some attempts have been made, as discussed in this BBC article:

A recent, two-year study for the United Nations Environment Programme, entitled The Economics of Ecosystems and Biodiversity (Teeb), put the damage done to the natural world by human activity in 2008 at between 2tn dollars (1.3tn GBP) and 4.5tn dollars.

At the lower estimate, that is roughly equivalent to the entire annual economic output of the UK or Italy.

A second study, for the UN-backed Principles for Responsible Investment (PRI), puts the cost considerably higher. Taking what research lead Dr Richard Mattison calls a more “hard-nosed, economic approach”, corporate environmental research group Trucost estimates the figure at 6.6tn dollars, or 11% of global economic output.

An important future goal is likely to be making these estimates more accurate and compelling.


category: biodiversity, ecology