Résumé
Random environmental fluctuations pose major threats to wild
populations. As patterns of environmental noise are themselves altered by
global change, there is growing need to identify general mechanisms
underlying their effects on population dynamics.
This notably requires understanding and predicting
population responses to the color of environmental noise, i.e.
its temporal autocorrelation pattern. Here, we show
experimentally that environmental autocorrelation has a large influence on
population dynamics and extinction rates, which can be predicted
accurately provided that a memory of past
environment is accounted for. We exposed near to 1000 lines of
the microalgae Dunaliella salina to randomly fluctuating
salinity, with autocorrelation ranging from negative to highly positive.
We found lower population growth, and twice as
many extinctions, under lower autocorrelation. These
responses closely matched predictions based on a tolerance curve with
environmental memory, showing that non-genetic inheritance
can be a major driver of population dynamics in randomly
fluctuating environments.