Box 1.3. Ecological Indicators and Biodiversity

The National Research Council in the United States identified three categories of ecological indicators, none of which adequately assesses the many dimensions of biodiversity:

• Ecosystem extent and status (such as land cover and land use) indicates the coverage of ecosystems and their ecological attributes.
• Ecological capital, further divided into biotic raw material (such as total species richness) and abiotic raw materials (such as soil nutrients), indicates the amount of resources available for providing services.
• Ecological functioning (such as lake trophic status) measures the performance of ecosystems.

Care must therefore be taken not to apply ecological indicators to uses they were not intended for, especially when assessing biodiversity. For example, biotic raw ecological capital measures the amount and variability of species within a defined area (C2.2.4). This may seem related to biodiversity, but it measures only taxonomic diversity. As such, this indicator does not necessarily capture many important aspects of biodiversity that are significant for the delivery of ecosystem services.

The most common ecological indicator, total species richness, is a case in point. TSR only partially captures ecosystem services. It does not differentiate among species in terms of sensitivity or resilience to change, nor does it distinguish between species that fulfill significant roles in the ecosystem (such as pollinators and decomposers) and those that play lesser roles. That is, all species are weighted equally, which can lead assigning equal values to areas that have quite different biota. Moreover, the value of TSR depends on the definition of the area over which it was measured and may scale neither to smaller nor to larger areas. Finally, TSR does not differentiate between native and non-native species, and the latter often include exotic, introduced, or invasive species that frequently disrupt key ecosystem services. Ecosystem degradation by human activities may temporarily increase species richness in the limited area of the impact due to an increase in exotic or weedy species, but this is not a relevant increase in biodiversity (C2.2.4).

Given the limitations of ecological indicators to serve as adequate indicators of biodiversity, work is urgently needed to develop a broader set of biodiversity indicators that are aligned against valued aspects of biodiversity. With the exception of diversity indices based on taxonomic or population measures, little attention has been paid to the development of indicators that capture all the dimensions of biodiversity (C4.5.1), although see Key Question 6 and C4.5.2 for more on indicators for the “2010 biodiversity target.”

Source: Millennium Ecosystem Assessment
  Ecosystems and Human Well-being: Biodiversity Synthesis (2005), p.21

Biodiversity & Human Well-being

Direct cross-links to the Global Assessment Reports of the Millennium Assessment

Box 1. Biodiversity and Its Loss— Avoiding Conceptual Pitfalls

Box 1.1. Linkages among Biodiversity, Ecosystem Services, and Human Well-being

Box 1.2. Measuring and Estimating Biodiversity: More than Species Richness

Box 1.3. Ecological Indicators and Biodiversity

Box 1.4. Criteria for Effective Ecological Indicators

Box 2. MA Scenarios

Box 2.1. Social Consequences of Biodiversity Degradation (SG-SAfMA)

Box 2.2. Economic Costs and Benefits of Ecosystem Conversion

Box 2.3. Concepts and Measures of Poverty

Box 2.4. Conflicts Between the Mining Sector and Local Communities in Chile

Box 3.1. Direct Drivers: Example from Southern African Sub-global Assessment

Box 4.1. An Outline of the Four MA Scenarios

Box 5.1. Key Factors of Successful Responses to Biodiversity Loss

Figure 3.3. Species Extinction Rates

Figure 1.1. Estimates of Proportions and Numbers of Named Species in Groups of Eukaryote Species and Estimates of Proportions of the Total Number of Species in Groups of Eukaryotes

Figure 1.2. Comparisons for the 14 Terrestrial Biomes of the World in Terms of Species Richness, Family Richness, and Endemic Species

Figure 1.3. The 8 Biogeographical Realms and 14 Biomes Used in the MA

Figure 1.4. Biodiversity, Ecosystem Functioning, and Ecosystem Services

Figure 2. How Much Biodiversity Will Remain a Century from Now under Different Value Frameworks?

Figure 2.1. Efficiency Frontier Analysis of Species Persistence and Economic Returns

Figure 3. Main Direct Drivers

Figure 3.1. Percentage Change 1950–90 in Land Area of Biogeographic Realms Remaining in Natural Condition or under Cultivation and Pasture

Figure 3.2. Relationship between Native Habitat Loss by 1950 and Additional Losses between 1950 and 1990

Figure 3.3. Species Extinction Rates

Figure 3.4. Red List Indices for Birds, 1988–2004, in Different Biogeographic Realms

Figure 3.5. Density Distribution Map of Globally Threatened Bird Species Mapped at a Resolution of Quarter-degree Grid Cell

Figure 3.6. Threatened Vertebrates in the 14 Biomes, Ranked by the Amount of Their Habitat Converted by 1950

Figure 3.7. The Living Planet Index, 1970–2000

Figure 3.8. Illustration of Feedbacks and Interaction between Drivers in Portugal Sub-global Assessment

Figure 3.9. Summary of Interactions among Drivers Associated with the Overexploitation of Natural Resources

Figure 3.10. Main Direct Drivers

Figure 3.11. Effect of Increasing Land Use Intensity on the Fraction of Inferred Population 300 Years Ago of Different Taxa that Remain

Figure 3.12. Extent of Cultivated Systems, 2000

Figure 3.13. Decline in Trophic Level of Fisheries Catch since 1950

Figure 3.14. Estimated Global Marine Fish Catch, 1950–2001

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.15. Estimates of Forest Fragmentation due to Anthropogenic Causes

Figure 3.16. Fragmentation and Flow in Major Rivers

Figure 3.17 Trends in Global Use of Nitrogen Fertilizer, 1961–2001 (million tons)

Figure 3.18 Trends in Global Use of Phosphate Fertilizer, 1961–2001 (million tons)

Figure 3.19. Estimated Total Reactive Nitrogen Deposition from the Atmosphere (Wet and Dry) in 1860, Early 1990s, and Projected for 2050

Figure 3.20. Historical and Projected Variations in Earth’s Surface Temperature

Figure 4. Trade-offs between Biodiversity and Human Well-being under the Four MA Scenarios

Figure 4.1. Losses of Habitat as a Result of Land Use Change between 1970 and 2050 and Reduction in the Equilibrium Number of Vascular Plant Species under the MA Scenarios

Figure 4.2. Relative Loss of Biodiversity of Vascular Plants between 1970 and 2050 as a Result of Land Use Change for Different Biomes and Realms in the Order from Strength Scenario

Figure 4.3. Land-cover Map for the Year 2000

Figure 4.4. Conversion of Terrestrial Biomes

Figure 4.5. Forest and Cropland/Pasture in Industrial and Developing Regions under the MA Scenarios

Figure 4.6. Changes in Annual Water Availability in Global Orchestration Scenario by 2100

Figure 4.7. Changes in Human Well-being and Socioecological Indicators by 2050 under the MA Scenarios

Figure 6.1. How Much Biodiversity Will Remain a Century from Now under Different Value Frameworks?

Figure 6.2. Trade-offs between Biodiversity and Human Well-being under the Four MA Scenarios

Table 1.1. Ecological Surprises Caused by Complex Interactions

Table 2.1. Percentage of Households Dependent on Indigenous Plant-based Coping Mechanisms at Kenyan and Tanzanian Site

Table 2.2. Trends in the Human Use of Ecosystem Services and Enhancement or Degradation of the Service Around the Year 2000 - Provisioning services

Table 2.2. Trends in the Human Use of Ecosystem Services and Enhancement or Degradation of the Service Around the Year 2000 - Regulating services

Table 2.2. Trends in the Human Use of Ecosystem Services and Enhancement or Degradation of the Service Around the Year 2000 - Cultural services

Table 2.2. Trends in the Human Use of Ecosystem Services and Enhancement or Degradation of the Service Around the Year 2000 - Supporting services

Table 6.1. Prospects for Attaining the 2010 Sub-targets Agreed to under the Convention on Biological Diversity