Washington State Kelp Threat Rating: data and analysis code

Abstract

The data and analysis code in this repository were produced in support of the Puget Sound kelp and eelgrass risk assessment project, funded by the Puget Sound Partnership under an award to University of Washington. Marine foundation species are under threat worldwide, including kelps in Washington State. Stressors such as warming, eutrophication, and reduced water quality—often linked to human activities—are generally well recognized, yet their relative severity and certainty have not been systematically evaluated. In order to complete a cumulative risk assessment for kelp in Washington state, a relative rating of the importance of individual threats to kelp was needed. To fill this gap, a panel of regional kelp experts built on a previously developed conceptual model of kelp stressors in the Salish Sea to rate the severity and scientific certainty of each stressor across several characteristics (magnitude, timing, spatial and depth extent, etc.). The panel performed the rating exercise for three taxa; Nereocystis, Macrocystis, and understory kelps, and two life stages; sporophyte (adult) and gametophyte (juvenile). Our process produced a rich dataset which can be separated by stressor, taxa, and life stage allowing broad application to support decision making and prioritization of kelp research, management, and conservation. The dataset contains the complete severity and certainty ratings from the expert panel (n = 6) and the accompanying code can be used to reproduce the analysis and plots presented in the resulting manuscript.