Human activities have converted the world’s terrestrial, freshwater and marine ecosystems throughout history, but in the last 50 years the extent and pace of this conversion has soared, resulting in what the Millennium Ecosystem Assessment calls “a substantial and largely irreversible loss in the diversity of life on Earth” (Millennium Ecosystem Assessment, 2005). The number of species at risk of extinction clearly reflects this loss of diversity, with 16,306 species of plants and animals listed as threatened globally. Biodiversity – plants, animals, microorganisms and the ecological processes that interconnect them – forms the planet’s natural productivity. Protecting biodiversity ensures a that wide range of “ecosystem services” like flood control and soil renewal, the production of commodities such as food and new medicines, and finally, spiritual and aesthetic fulfillment, will remain available for current and future generations.
Conventional management approaches have focused on individual resources, such as timber or fish production, rather than on ecosystems as a whole. Metrics to measure performance have similarly been limited to simple output quantities (e.g., metric tons of fish caught). Recently policy goals have shifted away from this sectoral approach to managing natural resources. The result has been additional legislation aimed at maintaining the health and integrity of entire ecosystems, known as the “ecosystem approach.” In addition to measuring the protection of highly endangered species, the 2008 EPI uses indicators that measure large-scale habitat conversion and the effective protected area conservation of terrestrial and aquatic ecosystems as a whole.
Global information about the distribution of biodiversity, the condition of species and natural ecosystems, and the major stresses to ecosystems is not readily accessible. Existing information tends to be locally focused, inconsistently formatted across studies, and dispersed across many scientific publications and databases. Moreover, because of disparities in data quality and availability by country, comparisons of biodiversity conservation on a global level often rely on data obtained through remote sensing. Many countries collect more detailed national-level data, however it generally is not suitable for the purposes of a global comparison. In response to this problem, some regions, such as the European Union, have begun establishing standards and protocols for biodiversity data collection. However even among countries participating in these efforts, significant information gaps remain. Because of these data gaps, the 2008 EPI biodiversity indicators are based on remotely sensed data.
A consequence of the types of data available is that currently most indicators must measure biodiversity indirectly. The majority of viable indicators reflect stresses on ecosystems rather that actual measures of ecosystem condition. Similarly, available indicators tend to demonstrate threats to individual species rather than long-term population trends.
Data quality and availability also vary by ecosystem. For example, more information is available for assessing terrestrial ecosystems and resources than aquatic ones. A lack of viable aquatic indicators is especially pronounced for freshwater systems. Data availability and indicator development also vary by the level of biodiversity observed. Specifically, spatial and empirical data exist for indicators that measure biodiversity on the habitat level, but indicators of species and genetic diversity are more limited in scope. Consequently, the 2008 EPI emphasizes habitat protection instead of species or genetic conservation.
Southern and Central Africa are well represented among biodiversity leaders, with the Central African Republic, Botswana, Zambia, Congo, Zimbabwe, and Malawi all among the top ten nations. Many of the lowest performers are small island nations; 18 of the 23 Alliance of Small Island States (AOSIS) nations included in the Biodiversity & Habitat subcategory score below 50. Another 16 AOSIS nations lack data and could not be included. These low scores can partly be attributed to poor remote-sensing data resolution, which can lead to an appearance of low performance. However, many of these small island nations are legitimately poor performers. Islands are known to frequently harbor high concentrations of unique species. At the same time, human habitation can place more extreme resource and habitat pressures per unit land area on small islands.
Only 8 countries are at the target level for effective protected area conservation, many of which have large tracts of sparsely inhabited land (e.g. Greenland, Saudi Arabia). In general, large countries perform well on effective protected area conservation, with Greenland, Saudi Arabia, the United States, Brazil, Russia, Australia, and Canada all earning scores of 70 or higher. Effective protected area conservation and the conservation risk index (CRI) are loosely correlated, although considerably more countries (38) meet the CRI target. Overall performance is higher in CRI because, unlike the effective protected area conservation index, it does not penalize insufficient protection of target biomes. Exceptions include some developed countries such as the United States and New Zealand, which long ago converted the vast majority of their highly productive biomes (for example grasslands), but now effectively conserve the remainder.
Performance on the critical habitat protection index is unrelated to either effective protected are conservation or CRI. A large percentage of AZE sites occur in the Caribbean and Central and South America, but of these countries only Costa Rica, Montserrat, the Dominican Republic and Venezuela protect above 50% of their sites. Guatemala is a notable underperformer in the region, protecting none of its 10 sites. Throughout the world other notable performers include Tanzania, protecting 8 of 9 sites, and Indonesia, which only fully protects 2 of its 29 sites.
Only 5 countries – Jordan, Ecuador, the Dominican Republic, Cameroon, and Germany, protect the target of 10% of their EEZ waters, and only 9 countries earn scores of above 50. This low performance may represent slower trends to prioritize marine habitat.
Achieving fine-scale resolution is a problem for data acquired by remote sensing techniques, particularly when assessing small islands and countries. Poor data resolution can lead to an effective absence of data and, even when data is available, small spatial errors can translate to large percentages of areas in question and thus skewed results. We envision that future EPI measurements may be able to take advantage of a new, global, finer-resolution dataset that is currently in development – the GLOBCOVER project. GLOBCOVER uses 300m MERIS (Medium Resolution Imaging Spectrometer Instrument) data, which will provide almost 10 times more information than previous datasets.
Even more important than increasing spatial resolution is increasing database continuity over time. Currently, no two global land cover datasets from different time periods can be confidently compared. The ability to identify land cover and land use trends from remotely sensed data in a timely manner is key to tracking performance. For example, many areas have been deforested in the past but are now relatively stable (e.g., the southern Brazilian Atlantic Forests), while others are undergoing rapid change (e.g., Borneo). Data from the satellite-based MODIS sensor is now being examined for temporal patterns, but so far it has only been processed for forests. The ability to confidently compare data from different time points is the single most important methodological issue for the development of future global biodiversity metrics.
Developing metrics to apply the effective protected area conservation index and the conservation risk index to freshwater ecosystems is also strongly recommended. Basic information on the distribution and health of different aquatic biomes, such as salt marshes, seagrass beds, headwater streams, and wetlands, is still missing. Additionally, there are no agreed upon targets of what level of “intactness” of freshwater systems is sustainable or sufficient. The lack of data and performance targets in freshwater and marine ecosystems limits the use of this and similar indicators within the EPI.
Other indicators that are currently being developed and used to monitor progress towards the Convention on Biological Diversity’s 2010 Targets show promise, as they can be applied on both global and national levels. These include the Living Planet Index developed by World Wide Fund for Nature (WWF) and the Zoological Society of London (ZSL), and the Red List Index developed by The World Conservation Union (IUCN ) and ZSL. The Living Planet Index looks at trends in the abundance of vertebrate species from the terrestrial, freshwater, and marine realms. The Living Planet Index also has the potential to look at trends in subsets of the vertebrate population, such as migratory species, those dependent on a particular ecosystem, or those impacted by different land uses. The IUCN Red List Index measures the changing state of global biodiversity. It has been calculated for birds, amphibians, and mammals and can help track progress in averting species’ extinction risk. Some countries have begun to adapt these indices for national assessments, and it is possible that they could be incorporated in future editions of the EPI.
