Managing for ocean biodiversity to sustain marine ecosystem services

www.frontiersinecology.org © The Ecological Society of America C evidence is accumulating from terrestrial, freshwater, and marine systems to suggest that sustainable ecosystem services depend upon a diverse biota (Daily et al. 1997; Loreau et al. 2001; Tilman et al. 2001; Wall et al. 2004; MA 2005; Sala and Knowlton 2006; Worm et al. 2006; Butler et al. 2007; Hector and Bagchi 2007). In principle, such knowledge should be useful in guiding a national ocean policy that maintains the services provided by oceans into the future. But does knowing the link between diversity and services usefully inform policy? We argue that management to sustain biodiversity could provide a critical foundation for a practical, ecosystem-based management (EBM) approach to the oceans. Globally, 60% of ecosystem services are degraded (MA 2005). These ecosystems provide food, shelter, recycling, and other support mechanisms that human communities require, but fundamental services are declining as ecosystems are unraveled by human impacts (Palmer et al. 2004). Marine ecosystems (Figure 1) provide a constellation of services: they produce food, receive and assimilate wastes, protect shorelines from storms, regulate the climate and atmosphere, generate tourism income, and provide recreational opportunities (Covich et al. 2004; MA 2005). The extraordinary diversity of the world’s oceans – across the different levels of ecosystems, habitats, species, functional roles, and genetic diversity (Carpenter et al. 2006; Sala and Knowlton 2006) – and the interconnections of marine, coastal, freshwater, and terrestrial ecosystems make managing ocean ecosystems crucial for long-term prosperity. Although degradation of ecosystems might be reversed through appropriate policies (MA 2005), there are substantial information gaps in our understanding of ecosystem processes (Carpenter et al. 2006), which impede practical ideas about implementing policy. EBM involves incorporating knowledge of ecosystem processes into management, but defining EBM and specifying how it can be implemented has been difficult, particularly for marine ecosystems (Arkema et al. 2006). Grumbine (1994) surveyed 33 definitions of EBM, and Arkema et al. (2006) detailed 17. However, even with this large number of definitions, fewer than 10% of plans created by resource managers addressed priority EBM criREVIEWS REVIEWS REVIEWS