COS 19-6 - Comparing apples and oranges: Thresholds of ecological indicators in response to environmental and anthropogenic pressures reveal common trends in multiple marine ecosystems

Tuesday, August 9, 2016: 9:50 AM
220/221, Ft Lauderdale Convention Center
Jamie C Tam, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Woods Hole, MA, Jason S. Link, Ecosystem Assessment Program, NOAA NMFS Northeast Fisheries Science Center, Woods Hole, MA, Scott Large, Science Advisor, ICES, Copenhagen, Denmark, Elliott Hazen, Southwest Fisheries Science Center, NOAA, Jameal F. Samhouri, Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, Kelly Andrews, Northwest Fisheries Science Center, NOAA, Stephani Zador, Alaska Fisheries Science Center, NOAA, Kirstin K. Holsman, Fisheries Ecology, Northwest Fisheries Science Center, NOAA Fisheries Service, Seattle, WA, Mandy A. Karnauskas, Southeast Fisheries Science Center, Miami, FL, Jamison M. Gove, NOAA Fisheries, Pacific Islands Fisheries & Inouye Regional Center, Honolulu, HI and Rebecca Shuford, Science and Technology, National Oceanographic and Atmospheric Administration, DC

Thresholds of ecological indicators are required to delineate ecosystem status. These thresholds represent points at which a small increase in one or many pressure variables results in an abrupt change of an ecosystem response.  Developing such ecosystem thresholds needs to include both environmental and anthropogenic pressures.  Here we develop thresholds using gradient forest and general additive model methods for a suite of ecological indicators in response to multiple pressures that convey ecosystem status for large marine ecosystems from the US Pacific, Atlantic, sub-Arctic and Gulf of Mexico coasts. 


We found observations of thresholds in ecological indicators based on multiple pressures.  Critical point analyses indicate that commercial fishing above approximately 2.5 t/km2and exploitation above 20-35% will result in a change in the direction of ecosystem structure and functioning, but that increases in environmental pressures can have both positive and negative effects. Our findings indicate that thresholds of ecological indicators are useful tools for comparing the impacts of environmental and anthropogenic pressures across multiple ecosystems and these critical points can be translated into Ecosystem-Based Fisheries Management decision criteria.