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EL NIÑO COUPLED WITH ANOMALOUS OCEAN WARMING CHALLENGE SENTINEL STATUS OF GIANT KELP AS AN INDICATOR OF CLIMATE CHANGE

The desire to use sentinel species as early warning indicators of impending climate change effects on entire ecosystems is attractive, but there is a need to verify that such approaches have a sound biological basis. Foundation species upon which other species depend offer great promise as sentinels because their decline can destabilize and collapse entire ecosystems. Anomalously warm conditions in the North Pacific followed by extreme warming of the 2015-16 El Niño allowed evaluation of the sentinel status of giant kelp, a coastal foundation species that thrives in cold, nutrient-rich waters and is considered sensitive to warming. Surprisingly, we found that giant kelp did not presage ecosystem effects of extreme warming off southern California despite its expected vulnerability to warm ocean conditions that were unprecedented in magnitude and duration. Fluctuations in the biomass of giant kelp and its associated biota remained within historical ranges despite 24 months of above average temperatures and below average nutrients. Sea stars and sea urchins were exceptions, plummeting due to disease outbreaks linked to the warming. Our results challenge the general perception that kelp-dominated systems are highly vulnerable to extreme warming events and question their general use as early indicators of climate change. The resilience of giant kelp to the unprecedented warming not only highlights the limitations in our understanding of kelp ecology, but exposes the more general risk of relying on supposed sentinel species that are assumed to be very sensitive to climate change.

Authors

Reed, D., University of California Santa Barbara, USA, dan.reed@lifesci.ucsb.edu

Washburn, L., University of California, Santa Barbara, USA, libe.washburn@ucsb.edu

Rassweiler, A., Florida State University, USA, rassweiler@bio.fsu.edu

Miller, R., University of California, Santa Barbara, USA, miller@msi.ucsb.edu

Bell, T., University of California, Santa Barbara, USA, thomas.bell@lifesci.ucsb.edu

Harrer, S., University of California, Santa Barbara, USA, harrer@ucsb.edu

Details

Oral presentation

Session #:059
Date: 03/03/2017
Time: 14:30
Location: 313 A

Presentation is given by student: No