Biological diversity is complex and far too difficult to measure in its entirety. Instead, we measure parts of it and use indicators to summarize what we know.
Some combine the bits of data into overall trends, rather like economic and stock market indicators. WWF's Living Planet Index (LPI) - which combines trends in species populations to give an overall view of the state of all biodiversity - is one example. It is a useful approach, but it depends on having good data. Other indicators focus on particular components of biodiversity - such as the fish population of a lake or sea.
Only a few, like the LPI, are widely accepted, and even these cannot be universally applied, because:
- Different parts of biodiversity matter to different people. Some depend on wildlife species for food; others value the beauty of nature; still others primarily value the freshwater delivered by intact ecosystems.
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- Data on components of biodiversity are scarce and variable; there have not yet been systematic surveys and routine monitoring of many of its most important aspects.
Things are improving as more data are generated and our priorities become clearer. A project called Biodiversity Indicators for National Use - involving Ecuador, Kenya, the Philippines and Ukraine - showed that many countries already have information that can provide useful indicators. But much needs to be done to find the best use for such information and to establish meaningful and repeatable measures.
Val Kapos |