Sea sick? Setting targets to assess ocean health and ecosystem services

Abstract

Abstract. The benefits provided by a healthy ocean are receiving increasing attention in policy and management spheres. A fundamental challenge with assessing ocean health and ecosystem services is that we lack a scientific framework for expressing ecosystem conditions quantitatively in relation to management goals. Here we outline and operationalize a conceptual framework for identifying meaningful reference points and quantifying the current ecosystem state relative to them. The framework requires clear articulation of management goals and is built on a review of current scientific understanding and assessment of data availability. It develops a structured approach for choosing among three classes of reference points, including: (1) functional relationships that establish the ocean state that can be produced and sustained under different environmental conditions, (2) time series approaches that compare current to previous capacities to obtain a particular ocean state in a specific location, and (3) spatial reference points that compare current capacities to achieve a desired ocean state across regional (or, if necessary, global) scales. We illustrate this general framework through the lens of ocean health defined in terms of a coupled social-ecological system, with examples from fisheries, marine livelihoods, and water quality in the USA. Assessment of ocean health and ecosystem services can be significantly influenced by the choice of indicators used to track changes in a management goal, the type of reference point selected, and how one measures the distance of the current state from the reference point. This framework provides flexible, standardized methods for evaluating ocean health and ecosystem services that can advance important components of ecosystem-based management, including marine spatial planning, ecosystem service valuation, and integrated ecosystem assessments.

Perspectives on a Global Observing System to Assess Ocean Health

“…For instance, fisheries management provides an example where such objective measures of stock status allow to adaptively manage the human impact on stocks and associated ecosystems. Indeed, Samhouri et al (2012) provide an example of how to set targets for sustainable fisheries under the framework of the application of the OHI. We need a similarly robust approach to measuring other actionable components of marine ecosystems.…”

Local and regional experiences with assessing and fostering ocean health

“…One limitation of OHI is that assessment scores are only as good as the underlying data, the knowledge of the system, and SMART reference points [54]; these are often lacking. Similarly, assessment scores are most useful at small spatial scales but there is often not the data, knowledge, and reference points to allow assessments at the finest scales.…”

Comparing Apples to Oranges: Common Trends and Thresholds in Anthropogenic and Environmental Pressures across Multiple Marine Ecosystems

“…There is a convergence of knowledge in multiple disciplines (social sciences, economics, ecology, oceanography) in current EBM research that aims to quantify this socio-ecological "sweet spot" (Levin et al, 2009;Link, 2010;Samhouri et al, 2012). While there is a great deal of interdisciplinary work being done in marine ecosystem science, there is a relatively limited set of comparative studies of ecosystem-level trends and thresholds-based reference points (e.g., Murawski et al, 2010;Samhouri et al, 2010Samhouri et al, , 2017Large et al, 2013Large et al, , 2015aFoley et al, 2015;Link et al, 2015;Connell et al, in press) which are required to fully assess the ability of ecosystem science to effectively manage large marine ecosystems.…”