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Statistical and spatial toolbox for the Ocean Health Index and CumulativeImpactsBenjamin D. Best 1,2 , Benjamin S. Halpern 1,2 & Darren Hardy 1,21 National Center for Ecological Analysis and Synthesis, 735 State St. Suite 300, Santa Barbara, CA, 93101 USAbbest@nceas.ucsb.edu, halpern@nceas.ucsb.edu, hardy@nceas.ucsb.edu2 Center for Marine Assessment and Planning, University of California, Santa Barbara, CA, 93106AbstractManaging sustainable use of the oceans necessitates quantifying the diverse array of benefits to humans as well asman-made pressures impacting ecosystems. A couple of frameworks have been developed to address these complextasks: Cumulative Impacts (Halpern et al., 2008; nceas.ucsb.edu/globalmarine) and the Ocean Health Index (Halpernet al., 2012; oceanhealthindex.org). We provide an overview of these frameworks and dive into a new toolbox forapplying similar analysis to your region and/or sector of interest. This new toolbox allows for modification of regions,layers, equations and other parameters. Three separate interfaces allow for varying levels of automation anduse cases: 1) a user-friendly application for recalculating the index, navigating paths of connected elements, andgenerating reports with visualizations; 2) a set of form-based tools for use in a scientific GIS workflow (ArcGIS oropen-source Kepler); and 3) programming interfaces (R, Python).IntroductionManaging sustainable use of the oceans necessitates quantifying the diverse array of benefits to humans as well asman-made pressures impacting ecosystems. Cumulative Impacts accumulates the footprint of human activities basedon habitat-specific stressor weights (Halpern et al., 2008). The Ocean Health Index is a broader framework that alsoincludes 10 broad goals akin to ecosystem services (Halpern et al., 2012). To facilitate widespread use of the index,this toolbox is being developed for easy recalculation of the index globally or on a finer regional basis, modificationof its parts, and interactive visualization of results. These tools will promote deeper understanding of this complexbut transparent framework, and highlight opportunities for realizing a healthier ocean.The Cumulative Impacts (CI) framework maps human activities against distinct marine ecosystems (see ecosystemsand pressures in Table 1). The measure of human pressure per 1 km 2 cell (P cell ) is the sum of the rescaled valuesof anthropogenic drivers (D i = [0 to 1]) for all drivers (i = 1, …, n) multiplied by the stressor weight (u i,j ) specificto the driver (i) and ecosystem (j), depending on the number of ecosystems (j = 1, …, m) present in the cell givenby an indicator variable (E j = {1 or 0}). = ∗ ∗ , At the coarsest level, the Ocean Health Index (OHI) per region (I region ) is a weighted average of 10 goals (Table1), given by the weight (α i ) of each goal (G i ) for all goals (i = 1, …, N). =∑ For the global analysis, the Exclusive Economic Zones (EEZ) were used to determine the reporting regions andthe goal weights were evenly weighted (i.e. all α i = 0.1 and ∑ =1). Core functionality of the toolbox is toallow for alternative reporting regions and goal weighting schemes.Each region’s goal is the average of the current status (x i ) and likely future status ( , ). The likely future status isa multiplier of the current status based on the past trend (T i ), which gets inflected upward by measures of resilience(r i ) and downward by pressures (p i ). A weighting term (β=2/3) gives trend twice the influence over the differencebetween resilience and pressures. The OHI pressures (p i ) are similar to the Cumulative Impacts pressures (P cell )except specific also to goals, and resilience is a function of ecological condition and governance. , = 1+ + 1− − ∗ 58