Percent of each freshwater ecoregion’s area covered with lakes and man-made reservoirs.
We calculated the percentage of the ecoregion that is covered by lakes and reservoirs using lake and reservoir polygons from the Global Lakes and Wetlands Database (GLWD) (Lehner and Döll 2004). This database represents the best available source for lakes and wetlands on a global scale (1:1 to 1:3 million resolution). The GLWD contains shoreline polygons of the 3,067 largest lakes (surface area greater than or equal to 50 km2) and 654 largest reservoirs (storage capacity greater than or equal to 0.5 km3) worldwide, as well as shoreline polygons of approximately 250,000 smaller lakes, reservoirs, and rivers (surface area greater than or equal to 0.1 km2). For our calculations, only lake and reservoir polygons were used. It was not possible to separate natural lake polygons from reservoirs.
These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.
Data derived from:
Lehner, B., and P. Döll. 2004. Development and validation of a global database of lakes, reservoirs and wetlands. Journal of Hydrology 296: 1–22.
These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.
For more about The Atlas of Global Conservation check out
the web map (which includes links to download spatial data and view metadata)
at http://maps.tnc.org/globalmaps.html.
You can also read more detail about the Atlas at http://www.nature.org/science-in-action/leading-with-science/conservation-atlas.xml,
or buy the book at http://www.ucpress.edu/book.php?isbn=9780520262560
