Measures of the effects of agricultural practices on ecosystem services Virginia H. Dale a, ⁎ , Stephen Polasky b a Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6036 USA b Department of Applied Economics, and Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN 55108 USA ARTICLE INFO ABSTRACT Article history: Received 31 May 2006 Received in revised form 19 April 2007 Accepted 22 May 2007 Available online 13 July 2007 Agriculture produces more than just crops. Agricultural practices have environmental impacts that affect a wide range of ecosystem services, including water quality, pollination, nutrient cycling, soil retention, carbon sequestration, and biodiversity conservation. In turn, ecosystem services affect agricultural productivity. Understanding the contribution of various agricultural practices to the range of ecosystem services would help inform choices about the most beneficial agricultural practices. To accomplish this, however, we must overcome a big challenge in measuring the impact of alternative agricultural practices on ecosystem services and of ecosystem services on agricultural production. A framework is presented in which such indicators can be interpreted as well as the criteria for selection of indicators. The relationship between agricultural practices and land-use change and erosion impact on chemical use is also discussed. Together these ideas form the basis for identifying useful indicators for quantifying the costs and benefits of agricultural systems for the range of ecosystem services interrelated to agriculture. © 2007 Elsevier B.V. All rights reserved. Keywords: Agriculture Chemical Erosion Land use Ecosystem services 1. Introduction Ecological systems both contribute to and are affected by the production of goods and services that are of value to people. We refer to the contribution of ecosystems to human well- being in short-hand notation as “ecosystem services.” Under- standing how agriculture impacts ecosystem services, which in turn affect agricultural productivity, is of particular impor- tance because of agriculture is a dominant form of land management. Globally, it is estimated that 38% of land is in agricultural uses (FAO, 2004), and excluding boreal lands, desert, rock and ice, this amount rises to 50% (Tilman et al., 2001). As Tilman et al. (2002) state: “Agriculturalists are the de facto managers of the most productive lands on Earth. Sustainable agriculture will require that society appropriately rewards ranchers, farmers and other agriculturalists for the production of both food and ecosystem services.” But appro- priately rewarding ranchers, farmers and other agriculturalists will require the ability to accurately measure ecosystem services in a verifiable quantitative manner. Agriculture and ecosystem services are interrelated in at least three ways: (1) agro-ecosystems generate beneficial ecosystem services such as soil retention, food production, and aesthetics; (2) agro-ecosystems receive beneficial ecosystem services from other ecosystems such as pollination from non-agricultural ecosystems; and (3) ecosystem services from non-agricultural systems may be impacted by agricultural practices. In some cases, tracing the interrelationships between agriculture and ecosystem services is fairly direct as when pollinators increase agricultural crop yields or conservation easements on agricul- tural lands provide habitat for bird species enjoyed by bird- watchers. In other cases, the contribution may be more indirect or complex, as for example when wetlands reduce the load of nitrogen in surface water originating from agricultural fields and destined for a coastal estuary where eutrophication causes hypoxic conditions and reduced fish productivity. ECOLOGICAL ECONOMICS 64 (2007) 286 – 296 ⁎ Corresponding author. Tel.: +1 865 576 8043; fax: +1 865 576 8543. E-mail address: dalevh@ornl.gov (V.H. Dale). 0921-8009/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.ecolecon.2007.05.009 available at www.sciencedirect.com www.elsevier.com/locate/ecolecon