To settle or protect? A global analysis of net primary production in parks and urban areas ☆ Daniel W. O'Neill ⁎, David J. Abson Sustainability Research Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK abstract article info Article history: Received 5 March 2009 Received in revised form 18 July 2009 Accepted 26 August 2009 Available online 28 September 2009 Keywords: Parks Urban areas NPP Human appropriation of net primary production (HANPP) Conservation planning Global land use We test—at the global scale—the hypothesis that human beings tend to build settlements in areas of high biological productivity, and protect (as parks) areas of low productivity. Furthermore, we propose an alternative measure of the extent and effectiveness of the global protected areas network based on potential net primary production (NPP 0 ). The average NPP 0 in urban areas and parks is calculated and compared to the average NPP 0 of the geopolitical regions and biomes containing these areas. Additionally, human appropriation of net primary production (HANPP) in parks is used as an indicator of the effectiveness of these protected areas. We find that in almost all regions of the world, humans have chosen to settle in the most productive areas. At the global scale, urban areas have considerably higher NPP 0 (592 g Cm -2 yr -1 ) than the global average (494 g Cm -2 yr -1 ), while parks have roughly average NPP 0 (490 g Cm -2 yr -1 ). Parks with an IUCN category of I–VI account for 9.5% of the planet's terrestrial NPP 0 , compared to 9.6% of its terrestrial area. Although protected area and protected NPP 0 are nearly equal, this equivalence is diminished by HANPP within parks. Globally, the average HANPP in all protected areas is 14% of their NPP 0 , and HANPP within parks increases as the park management category becomes less restrictive. Moreover, we find a positive correlation between HANPP in parks and the extent of urbanization in the surrounding region and biome. Area-based targets for conservation provide no information on either the quality of the areas we choose to protect, or the effectiveness of that protection. We conclude that NPP 0 and HANPP may provide an additional, useful tool for assessing the extent and effectiveness of the global protected areas network. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Human beings have transformed the global landscape more than any other species. We have built cities and roads, converted prairie lands to agriculture, and cleared vast expanses of forest. The extent of our impact on the landscape is largely related to the way that we use land, which ranges from urban development and agriculture to the protection of wilderness areas. As the global human population has grown, the area occupied by human settlements has increased, while the area remaining as wilderness has decreased. This expansion of the human niche has had a significant impact on other species. The rate of species extinctions is now 100 to 1000 times the level that would exist in the absence of human activities such as land transformation—the leading cause of biodiversity loss (Pimm et al., 1995; Vitousek et al., 1997). The issue of biodiversity loss is an important part of the Millennium Development Goals, a set of eight international objectives that 189 countries have agreed to achieve by the year 2015. Target 7B of these goals is to “reduce biodiversity loss, achieving, by 2010, a significant reduction in the rate of loss” (United Nations, 2008, p. 38). The dominant approach to reducing biodiversity loss is the creation of protected areas (i.e. parks). The International Union for Conservation of Nature (IUCN) defines a protected area as “an area of land and/or sea especially dedicated to the protection and mainte- nance of biological diversity, and of natural and associated cultural resources, and managed through legal or other effective means” (IUCN, 1994). As of 2006, approximately 11.6% of the planet's terrestrial and marine area was included in some form of protected area (WDPA Consortium, 2007). The appearance of percentage area targets in conservation planning dates back to the III World Congress on National Parks in 1982, where it was proposed that 10% of the area of each of the world's biogeographic regions should be protected (McNeely and Miller, 1984). At this time, approximately 3.5% of global land area was protected, so the target was seen as a bold yet realizable goal (Pressey et al., 2003). In 1987, the World Commission on Environment and Development recommended a higher target of 12% global protection Ecological Economics 69 (2009) 319–327 ☆ Special issue: "Analyzing the global human appropriation of net primary production: Trajectories, processes and implications", Guest eds. Karl-Heinz Erb, Helmut Haberl, Fridolin Krausmann. ⁎ Corresponding author. Tel.: +44 113 343 6466; fax: +44 113 343 6716. E-mail address: entropyhero@yahoo.ca (D.W. O'Neill). 0921-8009/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.ecolecon.2009.08.028 Contents lists available at ScienceDirect Ecological Economics journal homepage: www.elsevier.com/locate/ecolecon