Can Conceptual Models and Loop Analyses Advance Integrative Assessments of Marine Ecosystems?

Ecosystems comprise diverse arrays of components, processes, currencies and services; representing them in quantitative models is complex and data-intensive. However, integrative ecosystem assessments (IEAs) must confront this challenge in order to support management. Within NOAA’s IEA program, conceptual models have helped to formalize ideas of marine ecosystem structure, identify information gaps, and communicate and build relationships with managers and stakeholders. However, these conceptual models have not been analyzed to determine their plausibility, nor have they been used in evaluation frameworks to inform management strategies or identify tradeoffs. Here, we analyze a series of conceptual models from the California Current IEA. We first estimate their stability using qualitative network models (QNMs, or loop analyses), a less data-intensive method in which links between ecosystem components are simply given positive, negative, or neutral signs, along with estimates of certainty. The stability analysis demonstrates if our conceptual models have gaps or particularly sensitive components or links. We then combine pairs of species-centered QNMs and apply different management levers to see if the models can identify potential ecosystem responses and tradeoffs. These analyses may help determine if conceptual models are not just organizing and communication tools, but also a basis for strategic modeling and decision-making.