Addressing biodiversity loss requires knowledge about biodiversity, assessments of the effectiveness of policy and management decisions – usually through adaptive management – and decision making in accordance with the national biodiversity strategy, relevant biodiversity targets and other sustainable development objectives. Due to the complexity of biodiversity, incomplete taxonomic knowledge and high cost of biodiversity assessments and monitoring programmes, monitoring will typically rely on a small number of indicators, for which data are available.
Biodiversity indicators are information tools, summarizing data on complex environmental issues to indicate the overall status and trends of biodiversity. They can be used to assess national performance and to signal key issues to be addressed through policy interventions and other actions. The development of indicators is, therefore, important for monitoring the status and trends of biological diversity and, in turn, feeding back information on ways to continually improve the effectiveness of biodiversity management programmes.
Biodiversity indicators, when used to assess national or global trends, build a bridge between the fields of policy-making and science. Policy makers set the targets and measurable objectives, while scientists determine relevant variables of biodiversity, monitor current state and develop models to make projections of future biodiversity status. Once they are selected, indicators give direction to monitoring and research programmes.
Status, trends and causes of biodiversity loss
The third edition of the Global Biodiversity Outlook
demonstrates that there are multiple indications of continuing decline in biodiversity in all three of its main components — genes, species and ecosystems. For example:
- One-quarter of the world’s land is becoming degraded and terrestrial habitats have become highly fragmented, threatening the viability of species and their ability to adapt to climate change.
- Though deforestation, mainly the conversion of forests to agricultural land, is showing signs of decreasing in several tropical countries, it continues at an alarmingly high rate. Just under 130,000 square kilometres of forest were converted to other uses or lost through natural causes each year from 2000 to 2010.
- Coastal and marine ecosystems have been heavily impacted by human activities. Tropical coral reefs have suffered a significant global decline in biodiversity since the 1970s. Although the overall extent of living coral cover has remained roughly in balance since the 1980s, it has not recovered to earlier levels. Similarly since 1980, the loss of seagrass beds has averaged approximately 110 square kilometres per year, a rate of loss comparable to mangroves, coral reefs and tropical forests.
- The population of wild vertebrate species fell by an average of nearly one- third globally between 1970 and 2006, with the decline especially severe in the tropics and in freshwater ecosystems.
- Species in all groups with known trends are, on average, being driven closer to extinction, with amphibians facing the greatest risk and warm water reef-building corals showing the most rapid deterioration in status. Among selected vertebrate, invertebrate and plant groups, between 12% and 55% of species are currently threatened with extinction. Preliminary assessments suggest that 23% of plant species are threatened.
- Inland water ecosystems have been dramatically altered in recent decades. Wetlands throughout the world have been and continue to be lost at a rapid rate. Of 292 large river systems, two-thirds have become moderately or highly fragmented by dams and reservoirs.
- The intensification of fishing has led to the decline in large high-value fishes. About 80 percent of the world marine fish stocks for which assessment information is available are fully exploited or overexploited.
- Standardized and high-output systems of animal husbandry have led to an erosion of the genetic diversity of livestock. At least one-fifth of livestock breeds are at risk of extinction.
How the issue is being addressed under the CBD
The use of reliable indicators is essential to the development of measures designed to achieve the aims of the Convention. A number of indicators already exist which can be used to gauge progress towards the Strategic Plan for Biodiversity 2011-2020 and in particular the Aichi Biodiversity Targets. However for some aspects indicators will need to be further refined while new indicators will need to be developed. The Convention is developing guidance to assist Parties in the design of national-level monitoring programmes and indicators and a number of meetings will be convened throughout 2011 and 2012 to help with this process.