Climate change impacts on seabirds and marine mammals: the importance of study duration, thermal tolerance and generation time

Understanding climate change impacts on top predators is fundamental to
marine biodiversity conservation, due to their increasingly threatened
populations and their importance in marine ecosystems. We conducted a
systematic review of the effects of climate change (prolonged, directional
change) and climate variability on seabirds and marine mammals. We
extracted data from 484 studies (4808 published studies were reviewed),
comprising 2215 observations on demography, phenology, distribution, diet,
behaviour, body condition and physiology. The likelihood of concluding
that climate change had an impact increased with study duration. However,
the temporal thresholds for the effects of climate change to be
discernible varied from 10 to 29 years depending on the species, the
biological response and the oceanic study region. Species with narrow
thermal ranges and relatively long generation times were more often
reported to be affected by climate change. This provides an important
framework for future assessments, with guidance on response- and
region-specific temporal dimensions that need to be considered when
reporting effects of climate change. Lastly, we found that tropical
regions and non-breeding life stages were poorly covered in the
literature, a concern that should be addressed to enable a better
understanding of the vulnerability of marine predators to climate change.