Rangeland ecosystem services: shifting focus from supply to reconciling supply and demand

www.frontiersinecology.org © The Ecological Society of America T concept of ecosystem services – the benefits that society receives from ecosystems (Daily 1997) – has been the subject of considerable attention in recent years, but most studies to date have focused on the supply (Sala and Paruelo 1997; Havstad et al. 2007; Carpenter et al. 2009; Raudsepp-Hearne et al. 2010) and valuation (Costanza et al. 1997; Gómez-Baggethun et al. 2010) of such services. However, human use of ecosystem services depends on both the capacity of the landscape to supply, and on societal demand for, these resources (Tallis and Polasky 2011). Human demand is related to the social beneficiaries, and represents the other side of the ecosystem-services equation. Demand for specific ecosystem services varies among stakeholders (the individuals or groups who benefit from and/or have an active or passive influence on the delivery of these services; Lamarque et al. 2011). The demand may be described by the location, type, and intensity of requirement for services. Only a few studies have addressed the demand for ecosystem services besides provisioning services, and these have focused mainly on the perception of ecosystem services by different stakeholders (de Chazal et al. 2008; Quétier et al. 2010; Martín-López et al. 2012). Stakeholders vary in both their demand for and valuation of different ecosystems services. A new approach is to shift attention from supply and focus on demand relative to the available supply. This transition is important because a major focus of land management is implementing practices to ensure that supply meets or exceeds demand. Ecosystem services, such as clean drinking water, are provided regardless of whether those specific services are used, and demand for ecosystem services may also exist independently of the supply. Demand and supply can also overlap, resulting in use of that ecosystem service by society (Table 1). Rangelands are defined as “the land on which the potential native vegetation is predominately grasses, grass-like plants, forbs or shrubs” (Kauffman and Pyke 2001). Rangelands produce a great variety of ecosystem services, including the provisioning of food and fiber, carbon sequestration, maintenance of biodiversity (conservation), and recreation (Sala and Paruelo 1997). Globally, rangelands occupy approximately 54% of terrestrial ecosystems and sustain 30% of the world’s population (Reynolds et al. 2007; Estell et al. 2012), including a variety of stakeholders (eg farmers, tourists, conservationSHIFTING PARADIGMS IN DRYLANDS