Cornell Lab of Ornithology, Ithaca, New York, USA
Biodiversity monitoring projects collect a wealth of information about the abundance and distribution of organisms. For example, in the United States many hundreds of projects gather information on the distribution and abundance of birds annually. The result is that an estimated 60 million records over the past 100 years have been collected (with 10% growth annually), which represent arguably the most comprehensive time-series environmental data in existence. All of these data are gathered using Place-based protocols that focus on the characterization of a given area at a given time and generally result in a checklist of birds with some measure of abundance. Furthermore, monitoring data allows analysts to infer negative data, that is when an organism of the group under study was not reported, which is an essential component required for generating indices of abundance for the purpose of population monitoring. Analyses of these data show bird population trends at a variety of scales and provide extremely accurate measures of general biodiversity health.