Multiple Mechanisms Are at Play

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The introduction article, entitled “Mechanisms by which heatwaves impact seabirds”, provides a synthesis of marine heatwave research to date. This article, co-authored by Piatt, Arimitsu, and 5 other marine scientists, summarized 20 recent publications and identified specific mechanisms that cause impacts to seabirds, the types of mechanisms that are most common, and the associated effects or consequences (impacts) for each type of mechanism. These findings indicate that marine heatwaves can affect seabirds directly by creating physiological heat stress that affects behavior or survival, or indirectly by disrupting seabird food webs, largely by altering metabolic rates in ectothermic prey species, leading to effects on their associated predators and prey and their consequences for marine food webs. 

Mechanisms by which marine heatwaves affect seabirds are: 

• Habitat modification
• Physiological forcing
• Behavioral responses
• Ecological processes or species interactions

While many seabirds are vulnerable to these mechanisms of impact, most seabird species have experienced limited effects from marine heatwaves to date, owing to ecological and behavioral adaptations that buffer marine heatwave effects. However, the intensity and frequency of marine heatwaves is increasing due to climate change, and more seabird species may have difficulty coping with future heatwave events. Also, marine heatwave impacts can persist for years after a marine heatwave ends, so consequences of recent or future marine heatwaves could continue to unfold over time for many long-lived seabird species.

Overall, this body of work provides a synthesis of global heatwave science to promote awareness of current and potential future impacts and inform future management decisions arising from this significant population stressor.