As the monitoring and continuous assessment of all the components of biodiversity, as well as the pressures and threats that may affect them would be impractical, it is necessary to develop a system of indicators based on a species and ecosystems approach.
Biodiversity is not made up of units of equal significance: biodiversity value varies between species and ecosystems according to a range of factors, including the degree of genetic variation within species, the degree of difference between the various species in an ecosystem, complexity of lifestyle, the number of other species associated with a particular species, endemism, etc. Other variations relate to risk factors, particularly with respect to vulnerability to extirpation or extinction. Some conventional measures of biodiversity – such as numbers of species present – only give a very partial picture. For example, species numbers can increase after clearcutting a forest, but the newcomers usually consist of generalised or invader species, thus disguising losses of site-specific species. Ranking may be necessary, for example by rarity or vulnerability.
Indicators should cover: (a) Number of threatened/extinct species: many ecological processes depend on wildlife, including native mammals, birds, fish, reptiles, amphibians, plants and, especially, insects; (b) Wetlands: wetlands store and allow the slow release of large quantities of water, provide protection from erosion, provide habitat for waterfowl and fish, and offer recreational opportunities; (c) Protected areas: healthy natural habitat of adequate size is necessary for species' survival.
The Conference of the Parties (COP) of the Convention on Biological Diversity has requested that a core set of indicators be developed and used for national reporting and in the thematic areas important to the convention. The developed core set of indicators is intended to assist Parties and other Governments to design, initiate and/or improve their national monitoring programmes. The development of a core set of indicators for national reports should be accorded a high priority. Four groups of indicators have been elaborated for core set: state, pressure, use and response. The following model for development of indicator is the one thought to fit in the most appropriate manner by the Conference of the Parties (UNEP/CBD/SBSTTA/5/12/6): (a) The first track for immediate implementation considers existing and tested state and pressure indicators related to the conservation of biological diversity and to the sustainable use of its components; and (b) The second track, for longer-term implementation, should consider not only the state and pressure indicators, but also the identification, development and testing of response indicators for the three objectives of the Convention. The second track should also aim at continuous improvement of the state and pressure indicators for the first two objectives of the Convention.
The importance of establishing functional set of indicators and respective biodiversity monitoring system has been emphasised to certain extent in polices of most countries. The need for data-collection and compilation increases with the increase of international co-operation and obligations, and that is also acknowledged everywhere. At the same time the principles, historical causes and capacity for biodiversity monitoring programmes varies greatly among the countries.
In most countries the biodiversity indicators are part of state of environment reporting, but it has been admitted that biodiversity is one of the weakest areas in this field and only began to be considered as important and inseparable as a part of reporting. Usually only few indicators have been introduced and that is far from a sufficient and holistic reflection of all aspects of biodiversity. There are also very few cases, if any at all, where the biodiversity monitoring system is a data provider for national set of indicators. Usually these two fields stand apart.
The elaboration of a set of biodiversity indicators capable of reflecting pressure, state and response is regarded as a long-term goal achievable only in continuous and long process, which incorporates the joint effort of policy-makers, data managers and scientists. This process has been divided into rotating cycles consisting of three phases: identification of indicators in relation to policy goals, data collection and assessment of trends. The identification of indicators includes the evaluation of the quality of applied indicators and, if needed, reshaping of existing indicators and/or elaboration new ones.
Due to their ecological importance, numerical abundance, and sensitivity to a variety of toxicants and pollutants, amphipod crustaceans have long been known as sensitive environmental indicators. However, application and use of amphipods in such programs is limited to the few regions where ongoing comprehensive taxonomic and natural history investigations have been undertaken. Potential for amphipods as bioindicators exists in a wide variety of environments, especially in the tropics, but their incorporation into such programs is dependent upon completion of taxonomic surveys and inventories.
An Assessment framework has been proposed for conservation of biodiversity, called the Nature Capital Index (NCI). The NCI-framework aims at providing a quantitative and meaningful picture of the state and trends of biodiversity to support policy makers in a similar way as socio-economic figures such as GNP, employment and Price index.
The political commitment of European Union (EU) to elaborate biodiversity indicators and monitoring is expressed in European Community Biodiversity Strategy (ECBS). The EU promotes activities by the European Environmental Agency (EEA) and European Information and Observation Network (EIONET) and well as through Agricultural and other sectoral initiatives.
ECBS proposes to promote the development of system of indicators based on a species and ecosystems approach. The research on this system will be included in the new Multi-Annual Work Programme of the European Environment Agency and its Network. In addition, Eurostat is developing indicators of pressures affecting biodiversity in the context of its Pressure Indices Project.
Comprehensive monitoring and reporting as well as the use of assessments and indicators will help policy makers to identify whether goals are achieved within the deadlines set.
Indicator development is at relatively young stage and, as a result, many research and operational programmes with varying methodologies are being developed globally, nationally and sub-nationally under banner of "indicators". The differences in interpretations range over or combine: monitoring as a strict field based regular surveying of development: status/impacts in nature; monitoring of development of legal and administrative issues: responses and impacts of responses; monitoring as the same as reporting with analyses on the development of biodiversity, including both specific biodiversity or integrated reporting.
One of the main limiting factors in establishing a sound indicators-based reporting system is felt to be the availability of data in construction of indicators.
So far the importance of establishment of biodiversity monitoring and indicator system in not regarded a priority in environmental policy of most of the European countries. However, few countries pioneering in this field reveal the importance of the issue in national, regional and global level.
There are a number of international, regional and sub-regional programmes for state of environment reporting, which include the biodiversity field. However, biodiversity is the least elaborated in these programmes. Only few operational indicators for biodiversity exist to date and intensive work is needed to develop the set indicators capable to provide comprehensive insight to changes in biodiversity.