bringing indicators together


For the purpose of synthesizing the information contained in the full suite of indicators presented here, we categorize indicators broadly as drivers, states, and responses. Drivers may include everything from global climate effects to changes in local habitats, but generally are indicators that are thought to be responsible for producing change in the ecosystem. States include largely biological components of the ecosystem that respond to the underlying physical drivers. Responses can be biological, social, or economic in nature and can include ecosystem services (Kelble et al. 2013) or other processes that respond to changes in the biological ecosystem. Some responses, such as human population or fishing effort, can in turn be drivers as they also produce changes in the biological ecosystem. The categorization is used to highlight broad trends; however in reality these categorizations can be somewhat fuzzy in nature.

Plots of historical trends versus recent trends and historical variability versus recent variability allow for a composite view of the relative changes in the entire ecosystem over the last five years for which data are available (since 2010). The trend plot is produced by fitting a linear regression through the historical period and the recent period, and plotting the slopes on the two axes. Points falling toward the bottom right region denote indicators where the trends have recently decreased in comparison to historical trends, whereas points in the upper left region are indicators with trends that have increased compared to the historical trend. The variability plot is produced by calculating the absolute scaled year-to-year changes in indicator values for the historical period and recent period, and again plotting their means on the two axes. Points falling within the bottom right region denote indicators that have stabilized in the recent period, whereas indicators in the upper left region show more year-to-year variability in the recent period. In both plots, indicators are color-coded by broad categories.