Applications
Some authors note the distinction between the published "atlas" (usually a book but sometimes are web based systems) and the actual atlas data. The data itself cannot be recovered back from published atlases for alternate applications. Depending on the methodology used, there can be multiple applications for atlas data.
Atlases at a minimum, have an educational and recreational value. They provide information on the current distributions of birds and may be used by birdwatchers to assess the importance of their own observation records, know more about species or to plan trips. Distribution maps in atlases are usually far more accurate than those in field guides.
Atlases document distributions and populations for conservation and research. Species distribution ranges are important in assessing conservation criteria. Patterns of sympatry and allopatry are better observed when measures of relative abundance are also collected. When atlas projects are repeated over time it is possible to note changes in distribution. Reasons for change may be sought to identify causes when these changes are significant. Ecological niche models may be built to identify factors that are significant in influencing the occurrence of species. Many studies have examined the distributions of rare species and have noted that they often do not occur in species-rich areas. Studies using atlas data have helped in identifying key sites for conservation. Atlas data has also been used to identify biogeographic zones.
Atlases have helped in resolving taxonomic problems. DNA studies had shown that the two 'subspecies' of Eupodotis afra were distinct. The southern African atlas was able to demonstrate that these two 'subspecies' were disjunct in distribution except for a small area of overlap. The earlier distribution maps (made using what has been termed the 'shade-the-triangle' method) were totally misleading.
Atlas projects can involve several countries. The Southern African Bird Atlas Project (SABAP) was started in 1986 with data gathered from six countries: Botswana, Lesotho, Namibia, South Africa, Swaziland and Zimbabwe. This resulted in a published book form atlas in 1997 and the database held seven million distribution records. It has been used by planners, conservationists, researchers and for ecotourism apart from being used in over fifty research papers and eight academic dissertations.
Bird atlases can also serve as a guide for more detailed research. Atlas data can be used to develop sampling and survey designs for intensive studies.
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