Use of Structured Decision Making to Identify ...

Estuaries and Coasts DOI 10.1007/s12237-014-9822-5

Use of Structured Decision Making to Identify Monitoring Variables and Management Priorities for Salt Marsh Ecosystems Hilary A. Neckles & James E. Lyons & Glenn R. Guntenspergen & W. Gregory Shriver & Susan C. Adamowicz

Received: 30 September 2013 / Revised: 2 March 2014 / Accepted: 22 April 2014 # Coastal and Estuarine Research Federation (outside the USA) 2014

Abstract Most salt marshes in the USA have been degraded by human activities, and coastal managers are faced with complex choices among possible actions to restore or enhance ecosystem integrity. We applied structured decision making (SDM) to guide selection of monitoring variables and management priorities for salt marshes within the National Wildlife Refuge System in the northeastern USA. In general, SDM is a systematic process for decomposing a decision into its essential elements. We first engaged stakeholders in clarifying regional salt marsh decision problems, defining objectives and attributes to evaluate whether objectives are achieved, and developing a pool of alternative management actions for achieving objectives. Through this process, we identified salt marsh attributes that were applicable to monitoring National Wildlife Refuges on a regional scale and that targeted management needs. We then analyzed management decisions within three salt marsh units at Prime Hook National Wildlife Communicated by Iris C. Anderson H. A. Neckles (*) Patuxent Wildlife Research Center, U.S. Geological Survey, 196 Whitten Road, Augusta, ME 04330, USA e-mail: [email protected] J. E. Lyons Division of Migratory Bird Management, U.S. Fish and Wildlife Service, 11510 American Holly Drive, Laurel, MD 20708, USA G. R. Guntenspergen Patuxent Wildlife Research Center, U.S. Geological Survey, 12100 Beech Forest Rd., Laurel, MD 20708, USA W. G. Shriver Department of Entomology and Wildlife Ecology, University of Delaware, 531S. College Avenue, Newark, DE 19717, USA S. C. Adamowicz Rachel Carson National Wildlife Refuge, U.S. Fish and Wildlife, 321 Port Rd., Wells, ME 04090, USA

Refuge, coastal Delaware, as a case example of prioritizing management alternatives. Values for salt marsh attributes were estimated from 2 years of baseline monitoring data and expert opinion. We used linear value modeling to aggregate multiple attributes into a single performance score for each alternative, constrained optimization to identify alternatives that maximized total management benefits subject to refuge-wide cost constraints, and used graphical analysis to identify the optimal set of alternatives for the refuge. SDM offers an efficient, transparent approach for integrating monitoring into management practice and improving the quality of management decisions. Keywords Decision analysis . Salt marsh . Ecosystem monitoring . Environmental management . Measurable attributes . National Wildlife Refuge

Introduction Salt marshes are unique and highly productive ecosystems that provide a range of valuable services (MEA 2005; Barbier et al. 2011). The importance of these intertidal grasslands to fish and wildlife populations is well documented; in particular, they serve as nursery and feeding areas for many economically and ecologically important fishery species (Dionne et al. 1999; Deegan et al. 2000; Minello et al. 2003) and as critical breeding, migration, or wintering habitat for variety of bird species (Greenberg et al. 2006; Shriver and Greenberg 2012). Marsh vegetation also filters sediments, nutrients, and other pollutants from upland drainage and helps buffer shorelines from erosion by waves and currents, and marsh sediments have a high capacity for long-term carbon sequestration (Mcleod et al. 2011). However, despite the high value of the benefits derived from salt marshes, they are among the most threatened ecosystems in the world (MEA 2005; Bromberg

Estuaries and Coasts

Gedan et al. 2009). In the USA, human activities have altered, degraded, or destroyed salt marshes since the time of European settlement. As a result, more than half of the original salt marsh habitat has been lost (Kennish 2001) and the function of many remaining marshes is severely impaired (Bromberg Gedan et al. 2009). These impacts are exacerbated by accelerated rates of sea-level rise and other factors associated with a changing global climate (Titus and Richman 2001; Stevenson and Kearney 2009). Current efforts to reverse historical changes and restore salt marsh ecosystem services include removing tidal restrictions, eradicating invasive species, augmenting or excavating sediments, planting native vegetation, and remediating contaminant pollution. Management of coastal marshes thus requires complex decisions among many possible management interventions with associated, inherent trade-offs. Environmental monitoring is widely recognized as a crucial component of environmental decision making (Griffith 1998; Lovett et al. 2007). To be most useful, monitoring should be integrated into the decision-making system, involving open communication with stakeholders and clear links to management actions (NRC 1990; Nichols and Williams 2006). Effective environmental management thus depends in part on first, identifying appropriate monitoring variables, and second, using monitoring results to evaluate and select appropriate management strategies (NRC 1990; Lovett et al. 2007). Various salt-marsh monitoring programs have been developed to measure restoration success (e.g., Havens et al. 1995; Simenstad and Thom 1996; Short et al. 2000; Neckles et al. 2002) and to assess overall ecosystem integrity (Wigand et al. 2010, 2011). However, we know of none that is linked explicitly to evaluating and comparing multiple options for salt marsh management. Structured decision making (SDM) is a systematic approach to improving the quality of complex decisions that provides a framework for connecting monitoring metrics to management needs (Gregory and Keeney 2002; Keeney and Gregory 2005). Rooted in decision analysis, SDM involves identifying well-defined and measurable management objectives, potential management options, and the expected outcomes of management actions (Lyons et al. 2008; Conroy and Peterson 2013). A variety of optimization approaches are available to then guide selection of a preferred management alternative, but central to all are metrics that can be used to estimate and to evaluate the consequences of a specific management action with respect to a particular objective (Gregory et al. 2012). Therefore, use of SDM to frame natural resource decisions leads to logical selection of what to monitor while ensuring that monitoring information is focused on management needs (Nichols and Williams 2006; Lyons et al. 2008). Decision-analysis techniques have been applied to a variety of natural resource issues, including watershed management (Gregory and Wellman 2001; Merrick et al. 2005), sport

fisheries management (Peterson and Evans 2003), wetland habitat management for waterbirds (Lyons et al. 2008), whooping crane conservation (Runge et al. 2011), and mitigation of climate change impacts on forestry (Ohlson et al. 2005) and avian communities (Conroy et al. 2011). We used SDM to identify monitoring variables and prioritize management actions for salt marshes within the U.S. Fish and Wildlife Service National Wildlife Refuge System (NWRS) in the northeastern USA. The NWRS is managed according to the National Wildlife Refuge System Administration Act of 1966 as amended by the National Wildlife Refuge System Improvement Act of 1997, 16 U.S.C. 668dd-668ee. The law establishes wildlife conservation as the fundamental mission of the NWRS and that this mission be achieved by maintaining, and where appropriate, restoring the biological integrity, diversity, and environmental health of each refuge for the benefit of present and future generations of Americans. Coastal NWRS units protect approximately 423,000 ha of salt marsh habitat in the contiguous 48 states, much of which is located within the densely populated coastal zone. Few of these salt marshes are in pristine condition, so various management practices are planned routinely in efforts to restore and enhance marsh integrity and ensure ecosystem sustainability. Prioritizing NWRS salt marshes for application of management actions and selecting among the wide range of management options available require methods to evaluate marsh condition relative to multiple management objectives. Therefore, our goal was to develop monitoring and management tools that would be useful to inform complex decisions on NWRS salt marshes. We implemented the SDM process to inform local, refugespecific management decisions within the context of regional salt marsh management goals. Here, we present results for one representative refuge as a case example. Given widespread efforts to restore the historic function of salt marshes (Thayer 1992; MEA 2005), we think this approach has broad usefulness to improve the management, conservation, and monitoring of salt marshes globally.

Methods Overview SDM is a prescriptive approach to decision making that draws strongly from decision analysis with insights gained from other behavioral sciences, including cognitive psychology, group dynamics, and negotiation theory and practice (Gregory and Keeney 2002; Gregory et al. 2012; Conroy and Peterson 2013). At its most basic, SDM is a formalized process to connect outcomes to objectives in a way that is organized, inclusive, transparent, and defensible. We followed the systematic and deliberate steps described by Hammond et al. (1999) and Gregory and Keeney (2002) in applying

Estuaries and Coasts

SDM to salt marsh monitoring and management: (1) clarify the temporal and spatial scope of management decisions; (2) define objectives and attributes to evaluate whether objectives are achieved; (3) develop alternative management actions for achieving objectives; (4) estimate the consequences, or likely outcomes, of management actions in terms of the evaluation criteria; and (5) evaluate the trade-offs inherent in potential alternatives and select the optimum alternative to maximize management benefits. We organized these steps within our broad goals of identifying monitoring variables and evaluating management options for NWRS salt marshes. A primary key to effective decision making is engaging stakeholders in each step of the process (Keeney 1982; Gregory and Wellman 2001; Williams et al. 2009). Input from individuals who are knowledgeable about a natural resource management issue and are affected by the outcome of decision making is critical to accurately define the questions, objectives, and potential actions surrounding management needs, but equally importantly, meaningful stakeholder involvement in a decision also enhances the probability of successful implementation of agreed-upon alternatives (Williams 2011a). We involved SDM experts, research scientists representing multidisciplinary expertise in salt marsh ecosystems, FWS regional refuge managers, and FWS refuge-specific biologists in developing salt marsh management decision frameworks through a series of rapid-prototyping workshops. Collectively, workshop participants represented subject-matter experts, decision makers, and stakeholders regarding salt marsh management decisions. The rapid-prototyping approach advocates successive development of models, testing, and refinement to adequately and accurately depict the elements of a complex decision (Nicolson et al. 2002). We developed our first prototype decision framework at a week-long workshop in April 2008. Results from this workshop were used to guide preliminary monitoring of NWRS salt marshes in 2008 and 2009 (Neckles et al. 2013). The data gathered, and insight into ecosystem processes gained, through the preliminary monitoring were then used in a subsequent series of workshops in January 2012, to refine predictive models, evaluate trade-offs, and select the optimum management actions to achieve objectives. The decision-making prototype presented here is the result of this iterative process. Scope of Salt Marsh Management Decisions Decisions about restoration and other management of salt marshes within the NWRS occur at various temporal, spatial, and institutional scales. There are 33 National Wildlife Refuges with salt marsh habitat in the northeastern USA (Fig. 1), each containing from 1 to over 20 management units that span a broad size range (