Relative abundance of kelp forest habitat, by marine province. We developed estimates of abundance of kelp forests. Originally we gathered this information at an ecoregional scale, but we decided to summarize to province due to concerns about fine-scale accuracy. Where information was not readily available, provinces were labeled “no data.” We used the following data sources: Robinson, A. R., and K. H. Brink, eds. 1998. The Global Coastal Ocean, Regional Studies and Syntheses. New York: Wiley. ———, eds. 2006. The Global Coastal Ocean: Interdisciplinary Regional Studies and Syntheses. Cambridge, MA: Harvard University Press. Sheppard, C., ed. 2000a. Seas at the Millennium: An Environmental Evaluation, Volume 1: Regional Chapters: Europe, the Americas and West Africa. Oxford: Elsevier Science. ———, ed. 2000b. Seas at the Millennium: An Environmental Evaluation, Volume 2: Regional Chapters: The Indian Ocean to the Pacific. Oxford: Elsevier Science. ———, ed. 2000c. Seas at the Millennium: An Environmental Evaluation, Volume 3: Global Issues and Processes. Oxford: Elsevier Science. 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.