The Pilot analysis of global ecosystems (PAGE) provides a “big picture” view of ecosystems using indicators and maps at global and continental scales.
PAGE assessed five of the world’s major ecosystem types:
PAGE: Agroecosystems reveals that environmental damage threatens future world food production. (December 2000)
PAGE: Forest ecosystems shows that forest areas in developed countries continue to increase slightly, while clearance for agriculture, development, and logging in developing countries is reducing their forests by at least 140,000 square kilometers every year. (December 2000)
PAGE: Freshwater systems reveals that the world’s freshwater systems are so degraded that their ability to support human, plant and animal life is greatly in peril. (October 2000)
PAGE: Grassland ecosystems warns that the world’s grasslands have declined in their extent and condition, as well as their ability to support human, plant, and animal life. (December 2000)
The PAGE: Coastal and marine ecosystems warns that the planet’s coastal zone is in danger of loosing its capacity to provide fish, protect homes and businesses, reduce pollution and erosion, and sustain biological diversity. (April 2001)
Together, these ecosystem types cover most of the world’s terrestrial surface, a significant (and economically important) portion of the oceans, and account for the bulk of the goods and services humans derive from ecosystems.
A unique approach
What makes the PAGE study unique is that it evaluated the state of ecosystems by examining the condition of a range of goods and services these ecosystems produce, including:
- Food and fiber production
- Provision of pure and sufficient water
- Maintenance of biodiversity
- Storage of atmospheric carbon
- Provision of recreation and tourism opportunities
This “goods and services approach” makes explicit the link between the biological capacity of ecosystems and human well-being—between the condition of ecosystems and their potential to support human development.
Notably, the PAGE assessment considered not just the current level of production of goods and services, but also the capacity of the ecosystem to continue to produce these goods and services in the future. For example, in evaluating food production in the coastal and marine assessment, PAGE researchers looked not only at the current marine fish catch, but at trends in the condition of the fish stocks that contribute to this catch. In this way, the PAGE study—to the limited extent possible—addressed the question of the sustainability of current patterns of ecosystem use.
A global synthesis of current information
The first objective of PAGE was to review existing environmental assessments and compile available data into a globally comprehensive package. PAGE researchers synthesized information from dozens of sources:
- National, regional, and global data sets on food and fiber production.
- Sectoral assessments of agriculture, forestry, biodiversity, water, and fisheries.
- National State-of-the-Environment reports.
- National and global assessments of ecosystem extent and change.
- Biological assessments of particular species or environments.
- Scientific research articles.
- Various national and international data sets.
For each good and service, the PAGE study asked why it was important, and what shape it was in. In some cases, researchers also included information on the plausible future condition of the ecosystem.
The “big picture,” but with limitations
The goal of PAGE was not only to provide “state of the art” information on the condition of global ecosystems, but also to help identify gaps in data and information. In addition, PAGE was designed to demonstrate at a global level the utility of an integrated assessment approach – one that simultaneously assesses the range of goods and services an ecosystem produces rather than focusing on just one or two, such as timber production or biodiversity.
The PAGE findings provide a “big picture” view of ecosystem condition and change at a global or continental scale and indicate how these ecosystem characteristics are linked to development prospects. PAGE did not attempt to produce the more detailed site-specific data and information needed at a national scale by resource managers. Nor did it examine specific trade-offs among various goods and services, since that type of analysis is most meaningful at smaller scales such as a nation or river basin where these choices are actually made.
A truly integrated ecosystem assessment would focus not on categories such as “forests” and “grasslands,” as PAGE has done, but instead on spatially contiguous regions, such as a river basin, or even a nation. The Amazon basin ecosystem, for example, includes agriculture, coastal areas, grasslands, forest and freshwater. An integrated assessment of the Amazon would examine goods and services produced from this matrix of land uses and land cover (and trade-offs among them) rather than examining each in isolation.
However, at a global scale, the broad categories used by PAGE provide a useful way to present information, since the dominant issues and characteristics differ substantially from one category to the next. Moreover, these categories are useful to some of the global environmental institutions charged with the conservation and sustainable use of ecosystems. For example, these are the same categories used by the Convention on Biological Diversity.
Laying the groundwork for future assessments
The PAGE process, through its identification of key ecosystem indicators and data gaps, and in the breadth of its findings, has laid the substantive groundwork for the Millennium Ecosystem Assessment – an international effort to track ecosystem conditions and trends in a way that will allow governments and communities to better manage their use of ecosystems.