Cumulative Human Impacts on Marine Ecosystems

Figure 1. Global map of impact of anthropogenic stressors on marine biodiversity. Source: Halpern et al. (2008) Science 321: 1444-1445.

The Cumulative Human Impact on Marine Ecosystems indicator results can also be viewed and explored on the BIP Dashboard, which includes downloadable graphs of trends. Further graphs and maps are also available through the National Center for Ecological Analysis and Synthesis.

Cumulative impact assessment and mapping was developed in response to scientific and management needs to inform ecosystem-based management and marine spatial planning, both of which explicitly require such assessments. It also addresses the longer-standing need in species risk assessments to evaluating cumulative impacts rather than single-stressor responses. It has since been adapted and used in a wide range of policy, management, and scientific contexts.

Cumulative impact scores are surprisingly high for much of the world’s ocean in part because climate change, commercial fishing, and commercial shipping have a truly global reach and impact on marine systems. Coastal areas, where most human uses of the ocean are concentrated, are particularly heavily impacted.

Cumulative impact assessments can be used to address a range of policy questions related to the cumulative and interactive effects of multiple human uses and associated stressors on marine ecosystems and species, including but not limited to 1) identifying top threats, 2) prioritizing areas for mitigation or protection, 3) informing where new uses should or should not be permitted, and 4) identifying and prioritizing information gaps to be filled.

Coverage: Global and regional time series.

Scale: Not aggregated.

Time series available: 2008 onwards.

Possible disaggreagations: By region, by country.

Methodology: Cumulative impact maps are calculated at high resolution for global and sub-global assessments. All data and methods are freely available and documented elsewhere (see project website). Regional applications of cumulative impact mapping have been developed, and documented data and methods are available from those reports and websites.

Producing this indicator nationally: Individual stressor and cumulative impact measures are all reported at 1km2 resolution and thus can easily be summarized at any scale larger than that. Producing national level indicators is thus simple and has already been calculated and published in many cases.

Use at the national level: This indicator provides the only comprehensive, standardized, transparent, quantitative and repeatable means to assess and map cumulative human impacts, providing a unique measure of the likely ‘pristineness’ of a system. The methods are flexible to use for habitats, taxa, or individual species at any scale, and the results can be used to inform a very wide range of policy and management objectives. Most data and results from the initial assessment (published 2008) are currently available online, as are the tools, code and full set of data (raw to processed) for the most recent update (assessment year 2013, published in 2015). Results can also be found here.

Dozens of national and regional assessments have been done to date using this methodology. These efforts leverage higher resolution, higher quality and/or additional data available at the scale of assessment, allowing use of the best available data and science for the region. Two examples provide good case studies for regional, policy-relevant assessments: the Baltic Sea and the The Papahānaumokuākea Marine National Monument (PMNM), an area surrounding a string of atolls and banks known as the Northwestern Hawaiian Islands (NWHI). A synthesis of the patterns of all types of human impacts across the PMNM was identified as being a useful tool for managers applying local scale spatial management of the Monument with an ecosystem-based perspective. A more precise and comprehensive view of the spatial distribution of cumulative impacts in the Monument was provided by application of the cumulative impact mapping framework here on a finer scale (1 ha resolution) with location-specific data. Guidance on where to apply different management regulations and which threats are most in need of attention was provided by this analysis. The Baltic Sea assessment was developed by HELCOMM to inform reporting mandated by the E.U. Maritime Strategy Framework Directive

Examples of national use: Regional assessments have been conducted in over 65 locations and countries around the world, including the Baltic Sea, Antarctica, Mediterranean, California, and Australia. The intended purpose and outcome of these assessments has varied and included scientific discovery, conservation planning (e.g. marine spatial planning), informing policy, and indicator calculation for national or international biodiversity goals.

Availability of global data for national use: Freely available for non-commercial use.

Contact person for supporting national use: halpern@nceas.ucsb.edu

Publications and reports

Spatial and temporal changes in cumulative human impacts on the world’s ocean (Halpern et al. 2015).

Joint analysis of stressors and ecosystem services to enhance restoration effectiveness (Allan et al. 2012).

Placing marine protected areas onto the ecosystem-based management seascape (Halpern et al. 2010).

Using expert judgment to estimate marine ecosystem vulnerability in the California Current (Teck et al. 2010).

Global priority areas for incorporating land–sea connections in marine conservation (Halpern et al. 2009).

A map of human impacts to a “pristine” coral reef ecosystem, the Papahānaumokuākea Marine National Monument (Selkoe et al. 2009).

Mapping cumulative human impacts to California Current marine ecosystems (Halpern et al. 2009).

A global map of human impact on marine ecosystems (Halpern et al. 2008).

Interactive and cumulative effects of multiple human stressors in marine systems (Crain et al. 2008).

Evaluating anthropogenic threats to the Northwestern Hawaiian Islands (Selkoe et al. 2008).

Websites

Indicator data portal