Implications of acute temperature and salinity tolerance thresholds for the persistence of intertidal invertebrate populations experiencing climate change

To predict whether populations of marine animals will persist in the face of changing climate conditions, it is informative to understand how past climate conditions have shaped present-day tolerance thresholds. We examined 4 species of intertidal invertebrates (Nucella lamellosa, Littorina scutulata, Littorina sitkana and Balanus glandula) inhabiting the coasts of Vancouver Island, Canada, where the east coast experiences historically warmer sea surface temperature (SST), warmer low tide (i.e. emersion) rock surface temperature (RST), and lower sea surface salinity (SSS) than the west coast. To determine if east coast populations have higher tolerance thresholds to acute stress than west coast populations, animals from 3 sites per coast were exposed to stressful temperatures and salinities in common garden experiments. Emersion temperature tolerance differed between populations only in N. lamellosa and B. glandula, tolerance thresholds being 1.4-1.5 °C higher on the east coast. Water t...