Why Ecosystem-Based Management?

Karen L. McLeod and Heather M. Leslie

As illustrated by the preceding stories of ice bears and Puget Sound, ocean and coastal ecosystems around the globe are in trouble. Both the severity and scale of impacts to these systems—including those from climate change, biodiversity loss, overfishing, pollution, coastal development, habitat loss, and fragmentation—are increasing (MA 2005a, b), with no corner of the globe untouched (Halpern et al. 2008a). Acting in concert, these impacts decrease the ability of marine ecosystems to deliver vital ecosystem services to humankind, such as abundant seafood, clean water, renewable energy, and the protection of coastal areas from storm damage.

The unprecedented environmental challenges facing the oceans require us as scientists, practitioners, and citizens to embrace a broader vision than ever before of what we want to achieve through coastal and ocean management (UNEP 2006). This vision must encompass not only the long-term health of coasts and oceans, but also human well-being. Sustaining the long-term capacity of systems to deliver ecosystem services is the core goal of ecosystem-based management (EBM) for the oceans (Rosenberg and McLeod 2005). Moving forward with EBM requires synthesizing and applying knowledge from across the social and natural sciences as well as the humanities (Leslie and McLeod 2007) and raises numerous questions:

• How can we better account for the interactive and cumulative effects of the growing number of human activities affecting marine ecosystems?

• How well do we understand feedbacks between the social and ecological components of systems, and what are the broader implications of these linkages?

• In an increasingly dynamic world, how can management institutions respond more rapidly to changing, and often surprising, conditions?

• How can small-scale management decisions make a difference in light of large-scale change (especially climate change)?

• How can we better recognize that systems are approaching critical thresholds? In other words, how do we know how likely they are to shift to a fundamentally different state (e.g., from coral to algal dominance on tropical reefs) that will produce a radically different set of services?

• To what extent are these shifts reversible (especially over the scale of a human lifetime)? How can we identify and bolster attributes that decrease vulnerability to such shifts?

We tackle these and related questions in this book through synthesis of the science, policy, and practice of ecosystem-based management.

What Is Ecosystem-Based Management for the Oceans?

EBM is a new approach to managing the range of human activities that affect marine ecosystems, as called for by numerous national and international bodies (WSSD 2002; POC 2003; USCOP 2004). In 2005, more than two hundred academic scientists and policy experts from US institutions agreed by consensus on the following definition of EBM for the oceans: "Ecosystem-based management is an integrated approach to management that considers the entire ecosystem, including humans. The goal of ecosystem-based management is to maintain an ecosystem in a healthy, productive and resilient condition so that it can provide the services humans want and need. Ecosystem- based management differs from current approaches that usually focus on a single species, sector, activity or concern; it considers the cumulative impacts of different sectors" (McLeod et al. 2005). The following key elements are based on that definition:

1. Connections At its core, EBM is about acknowledging connections (Guerry 2005; Leslie and McLeod 2007), including first and foremost, the inextricable linkages between marine ecosystems and social systems. Human well-being is intimately connected to ecosystems through the delivery of ecosystem services across a range of scales. Cultures, economies, and institutions form and evolve in response to their local or regional ecosystem contexts. Human behavior, including the extent, intensity, and type of activity, affects natural systems. Humans interact with coasts and oceans as individuals (consumers, surfers, or fishers), as organizations (local fish markets or canneries), and as institutions (trade organizations, fishery management councils, or conservation organizations), each within a particular cultural context. These dynamic, linked systems of humans and nature are called "coupled social–ecological systems" (fig. 1.1).

EBM is fundamentally a place-based approach, and coupled systems occur across a range of spatial scales from a local ecosystem, such as an individual estuary, to an entire large marine ecosystem, such as the California Current off the US west coast. Thus, there is no single "correct" scale at which to do EBM. Instead, it is an approach to be implemented over a range of scales, acknowledging the connections and leaky boundaries among scales.

2. Cumulative impacts EBM focuses on how individual actions affect the ecosystem services that flow from these coupled systems. In other words, what are the cumulative impacts of multiple activities, both within and among sectors, on the delivery of ecosystem services? Accounting for cumulative impacts also involves recognition of interactions with drivers of change that operate over smaller or larger scales than the scale of management (see Guichard and Peterson, chap. 5 of this volume, for more on cross-scale interactions). Inevitably, a comprehensive accounting of cumulative impacts requires that sectors ultimately work toward a common goal (as expanded upon by Rosenberg and Sandifer in chap. 2 of this volume).

3. Multiple objectives EBM focuses on the range of benefits that we receive from marine systems, rather than single ecosystem services. In a particular...