Accurate species distribution data is necessary to address biodiversity challenges. To save endangered species, conservationists need to know which species populations are contracting or expanding. Restoring an ecosystem requires an accurate picture of how the ecosystem existed historically. Unfortunately, existing global data collections such as the Global Biodiversity Information Facility and IUCN Red List underrepresent some geographic areas, especially in the tropics, and may not show accurate distribution or trends for many species that live there. A further problem with newer datasets is that conservation organizations have focused largely on endangered species and nature reserves and lack the broad baseline data that may be necessary for future conservation problems.
A new study measures how well existing data compilations cover the Galliformes, an order that is well-studied and contains many threatened species. The datasets surveyed included museum collections, scientific articles, banding records, bird atlases, and birders' trip reports (archived on sites such as travellingbirder.com). Museum collections are the most significant source of historical distribution data, and scientific literature has gained importance over time. Birding reports are a relatively new phenomenon and still account for relatively few records, with most of those coming from birding hotspots.
The data sources vary in how much geographic area they cover. Museum collections are the most comprehensive as a whole, though individual collections may be more localized. Scientific literature covers western Europe, China, and southern Asia well, but not as many studies are available for other regions. Banding data and atlases were largely confined to western Europe. Birding trip reports provide broader coverage than banding or atlases but are concentrated in well-known hotspots and easily accessible locations. Because active specimen collecting has declined, contemporary data sources are less geographically comprehensive than older ones (see maps below).
The authors offer three suggestions for improving the geographic coverage and usability of biodiversity data:
- Museum collections and sightings data from scientific literature should be catalogued in electronic databases to make historical data more accessible.*
- Observation records should include a date and location, preferably with geographic coordinates, and be incorporated into a central database to avoid fragmentation.
- Observers should report all species rather than just rare or threatened ones and should look outside of known biodiversity hotspots.
* Though the authors do not cite it specifically, the North American Bird Phenology Program still needs volunteers to scan and transcribe thousands of historical observations.
Boakes, E., McGowan, P., Fuller, R., Chang-qing, D., Clark, N., O'Connor, K., & Mace, G. (2010). Distorted Views of Biodiversity: Spatial and Temporal Bias in Species Occurrence Data PLoS Biology, 8 (6) DOI: 10.1371/journal.pbio.1000385