Data from: Characterizing driver-response relationships in marine pelagic ecosystems for improved ocean management

Scientists and resources managers often use methods and tools that assume ecosystem components respond linearly to environmental drivers and human stressor. However, a growing body of literature demonstrates that many relationships are non-linear, where small changes in a driver prompt a disproportionately large ecological response. Here we aim to provide a comprehensive assessment of the relationships between drivers and ecosystem components to identify where and when non-linearities are likely to occur. We focus our analyses on one of the best-studied marine systems, pelagic ecosystems, which allowed us to apply robust statistical techniques on a large pool of previously published studies. In this synthesis, we (1) conduct a wide literature review on single driver-response relationships in pelagic systems, (2) use statistical models to identify the degree of non-linearity in these relationships, and (3) assess whether general patterns exist in the strengths and shapes of non-linear relationships across drivers. Overall we found that non-linearities are common in pelagic ecosystems, comprising at least 52% of all driver-response relationships. This is likely an underestimate, as papers with higher quality data and analytical approaches reported non-linear relationships at a higher frequency - on average 11% more. Consequently, in the absence of evidence for a linear relationship, it is safer to assume a relationship is non-linear. Strong non-linearities can lead to greater ecological and socio-economic consequences if they are unknown (and/or unanticipated), but if known they may provide clear thresholds to inform management targets. In pelagic systems, strongly non-linear relationships are often driven by climate and trophodynamic variables, but are also associated with local stressors such as overfishing and pollution that can be more easily controlled by managers. Even when marine resource managers cannot influence ecosystem change, they can use information about threshold responses to guide how other stressors are managed and to adapt to new ocean conditions. As methods to detect and reduce uncertainty around threshold values improve, managers will be able to better understand and account for ubiquitous non-linear relationships

Summary statistics and ancillary data of published single driver-response relationships in pelagic marine ecosystems

We created a database of published single driver-response relationships in marine pelagic ecosystems that were deemed significant based on p values ≤ 0.05 or were included in best-fit models identified through model selection. Multiple summary statistics were recorded (when available) in the database in an effort to explore variation in driver-response relationships in the present study and to be made available for researchers for future studies. The summary statistics include published or derived shapes of the relationships (linear, non-linear or specific functional forms), sample size, quantitative estimates of ecological thresholds, p values, R^2, deviance explained, correlation and regression coefficients, and model covariates (if multivariate model). In addition, we collected ancillary data on study characteristics to explore the variation in driver-response relationships and to identify the most robust papers with respect to statistical methods. The ancillary data in our database include ecosystem type (enclosed bay or sea, coastal pelagic, continental shelf and continental slope/oceanic), local region, ocean basin, large marine ecosystem, temporal scale of study, functional level (i.e., individual, population, community) and species trophic level (TL 1-4) of ecological response, primary productivity (mgC/mg2/day) and the statistical methods used by the authors. Estimates of species trophic level and primary productivity were obtained from the Sea Around Us Project (http://www.seaaroundus.org/). See Supplement Table S1 for additional description of data columns. The references in the database are cross-referenced with Table S1 Literature Cited.docx