ORIGINAL PAPER Using successional theory to measure marine ecosystem health Stuart A. Sandin • Enric Sala Received: 15 February 2011 / Accepted: 28 October 2011 / Published online: 9 November 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Marine ecosystems are diverse and complex, providing significant challenges to the development of generalizable metrics of ecosystem health. Of particular concern is the varied form of change caused by multiple human activities, which limits the capacity to generate a single measure to encapsulate the overall condition of the ecosystem. Here we consider how successional theory can help to simplify our understanding of marine community structure, especially when viewed in context of human disturbance. During succession, the emergent properties of communities change in predictable ways. As communities mature, there is an increase in total production and biomass, the mean size of organisms, the level of internal recycling of food and nutrients, and the mean trophic level. Using a set of multi-species trophic models, we explore the changes in community structure that are likely to occur during succession. These changes include increases in biomass within trophic levels due to decreased rates of energy and food loss through trophic and production inefficiencies, and potential shifts from top-down control early in succession to bottom-up later. Because human activities disproportionately favor early- successional species, we can gain insights by considering community degradation in the context of succession being played in reverse. Indicators of health based on ecological succession thus provide a mechanistic view to measure the impact of human activities (both positive and negative) on marine ecosystems. Keywords Trophic dynamics  Community development  Top-down  Bottom-up S. A. Sandin (&) Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, USA e-mail: ssandin@ucsd.edu E. Sala Centre d’Estudis Avanc ¸ats de Blanes, Consejo Superior de Investigaciones Cientı ´ficas, 17300 Blanes, Spain E. Sala National Geographic Society, Washington, DC 20036, USA 123 Evol Ecol (2012) 26:435–448 DOI 10.1007/s10682-011-9533-3