Biodiversity Indicators in

Only a fraction of the hundreds of biodiversity indicators that have been proposed have been implemented on a regular basis (CBD 2003c; Delbaere 2002b). The most commonly used indicators are species richness, number of threatened and extinct species, number of endemic species, trends in abundance of particular species, areal loss of ecosystems, and the percentage of area protected and its derivatives. Some of these indicators are insensitive, provide perverse messages, or are not an indicator of state but of response. Biodiversity indicators currently in use and proposed under the CBD are listed in Tables 16.1 and 16.2.

Many biodiversity measures had their origins in the taxonomic disciplines, which continue to have a strong influence through their emphasis on creating complete and

Table 16.1. List of single indicators (single variable related to a reference value) that are in use.

Type

Indicator (not exhaustive)

Question

State and Trend

Ecosystem Area of ecosystem type (e.g., forest, agriculture, built-up land)

Hotspots (areas of high endemism experiencing high human impact)

Species Trends in representative species, particular taxonomic groups, exploited species, endemic species, migratory species, Red List species

Percentage of threatened and extinct species in particular groups

Structure Trends in structure variables (e.g., canopy cover, ratio of dead to living wood, percentage area vital coral reefs)

How much natural area remains, how much is agricultural, and how much is built up?

Which ecosystems with high diversity of endemic species are threatened?

What is the quality of the remaining natural area and agricultural area? What are the trends at species level?

Which species are threatened?

What are the trends of ecosystem structures?

(continued )

Table 16.1. List of single indicators (single variable related to a reference value) that are in use (continued).

Type

Indicator (not exhaustive)

Question

Genes Number and share of livestock breeds and agricultural plant varieties Number of endangered varieties of livestock breeds and agricultural crops Share of major varieties in total production for individual crops

II. Pressures and Threats

Physical Annual conversion of self-generating area as a percentage of remaining area

Change in mean temperature and precipitation

Road density

Damming and canalization of rivers Fire

Chemical Acid deposition P or N deposition

Exceeding soil, water, or air standards for particular pollutants

Biological Total number of invasive species

Total amount harvested per species Indirect Human population density, gross national product

III. Use

Provisioning Total amount harvested per species or species group

Per capita wood consumption Regulating Carbon stored in forests

Cultural Total revenue from ecotourism

IV. Response

Legislation Total number of protected species as a percentage of particular groups

Which genetic resources are threatened?

What are the size of the pressure and its trend?

What factors influence the direct pressures?

What is the use? Is it sustainable?

How many people depend on the system?

What is the contribution to gross domestic product?

Table 16.1. List of single indicators (single variable related to a reference value) that are in use (continued).

Type Indicator (not exhaustive) Question

Percentage protected area by IUCN category

Targets National Biodiversity Strategy and

Action Plan objectives met Expenditure Expenditure of abatement and nature management measures (US$)

Management Number of protected areas with management plan Number of threatened and invasive species with a management plan Effectiveness of protection measures in protected areas

Nature research capacity, in number of people

Conservation policy capacity, in number of people

Nature site management in number of people

Number of physical and chemical standards

Number of physical, chemical, and biological variables measured Local site support groups and number of volunteer monitors

V. Capacity

Personnel

Legislation Monitoring

Source: CDB (2003c).

Table 16.2. Composite indicators that are currently in use.

Group

Indicator

Source

General state

Natural Capital Index

ten Brink (2000)

Wilderness

Conservation International

Living Planet Index

Loh (2002)

Last of the Wild

Sanderson et al. (2002)

Biodiversity Intactness Index

Scholes and Biggs (2005)

Trends of

Species Assemblage Trend Indices

Gregory et al. (2002),

components

(e.g., Bird Headline Indicator,

Loh (2002)

Living Planet Index)

Threat

Red List indicators on

IUCN (2002)

species groups

Hotspots

Myers et al. (2000)

Human Footprint

Sanderson et al. (2002)

Pressures

Total Pressure Index

UNEP (2002)

Habitat—species matrix

(agricultural practices)

Uses

Sustainability of total use

Responses

Effectiveness of environmental

measures

Effectiveness of area protection

Effectiveness of site management

Source: CBD (2003c).

correct lists of species, hence efforts such as the Global Biodiversity Information Facility and Species 2000 (www.gbif.org/GBIF_org/what_is_gbif and www.sp2000.org). The rational structure such initiatives bring is welcome, but taxonomic completeness, if achievable at all, is still many decades down the road. Given the indications that the current rate of extinction is abnormally high, urgency is paramount, and robust and scientifically defensible shortcuts are needed. Absolute taxonomic completeness is not necessary to measure biodiversity loss. Sampling a limited number of well-described species can provide sufficient information to guide interventions.

The main conservation advocacy groups have relied on the perceived threat of extinction, captured in Red Data Lists, because these do not require complete species inventories. Flagship species, those with high public appeal, have attracted a disproportionate amount of attention. Over the past decade the policy focus has shifted toward an ecosystem-based approach, which is intended to be more holistic. Rather than focusing on individual species, there is growing emphasis on the protection of hotspots containing multiple endemic species in threatened locations. There is also a move toward protection of large untransformed areas at the ecosystem scale, based on indirect measures or expert judgment.

Another recent trend is toward the use of abundance-based indices rather than species richness indices. Abundance-based indices have circumvented data limitations by focusing on a small number of well-studied species (Gregory et al. 2002; Loh 2002), using models to supplement inadequate data series (ten Brink 2000), or using expert judgment in place of population censuses (Scholes and Biggs 2005).

In October 2003, the CBD accepted a working paper that proposes eighteen indicators for application at national scale (CBD 2003d). They include measures at all three levels (ecosystem, species, genetic) and all aspects (composition, structure, and function) but are not intended to be comprehensive or integrated. They are the result of a consultation process that began around the time of the Global Biodiversity Assessment (1995).

Because of the lack of data on biodiversity trends, there is a tendency to use indicators of pressure (drivers) instead. The Geobiosphere Load (Moldan 1997) and Ecological Footprint (Wackernagel et al. 2002) are indicators of pressure. Some pressures, such as population density and household dynamics, are easily quantified (Liu et al. 2003). It is generally recognized that human-dominated landscapes are species poor or invaded by alien species (Araujo 2003). Human appropriation of photosynthesis products (Vitousek et al. 1986; Rojstaczer et al. 2001) reduces the energy available to support wild populations and ecosystems.

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