The study of multiple factors in an ecosystem can be difficult due to irregular patterns in environmental conditions known as ‘environmental mosaics’.  The complexity that results from the interplay of these factors makes it difficult to predict how natural systems will respond to climate change.  A recent study by a team of researchers – that includes Professor Brian Helmuth – examines how varying environmental conditions impact the survival of the California mussel.

In the study, recently published in the journal Ecology Letters, the team quantified mussel survival by investigating both mussel growth patterns as well as predation by whelks at seven locations along the California Current System.  The researchers focused on how growth and predation change in relation to water acidity, mussel body temperature, and chlorophyll concentration, which is used to measure food availability.  These parameters were monitored for a six-month period.

The experiment indicated that it is essential to account for spatial variability in the overlap of these environmental factors when predicting mussel success in ecosystems.  For example, growth was highest and predation lowest at locations where pH was low and food availability was high.  Conversely, growth rates were slowest and predation highest at sites where pH was low and low tide temperatures were high.

Results illustrated that locations as close as 130 meters apart can have significantly different rates of mussel growth and predation.  Of particular significance, were the differences in acidity and food availability at these sties.  In addition, small changes in environmental conditions can greatly influence mussel survivorship by altering the interactions between mussels and predatory dog whelks.  In short, small changes in one of several ‘environmental mosaics’ to which mussels are exposed can greatly alter their survival.

This work informs future climate change research, as the results illustrate the importance of context dependency in assessing the stability of an ecosystem. As climate change continues to impact ocean conditions, understanding the impact on important basal resource species like mussels will be essential in predicting how entire communities and ecosystems will respond.