Climate change and increased environmental variability: Demographic responses in an estuarine harpacticoid copepod

Climate change models predict that in the future, extreme events will be more common and of greater magnitude. In the southeastern United States, this is expected to include increased precipitation and more frequent extreme precipitation events, resulting in more freshwater runoff into coastal habitats. Marine and estuarine communities in this region can expect more frequent and larger salinity reductions if climate change model predictions are realized. We studied a benthic harpacticoid copepod to test the effects of environmental variability, in the form of estuarine salinity reductions, on vital rates. Specifically, we tested the effects of 3-day salinity reductions on the harpacticoid copepod Amphiascus tenuiremis. We varied the magnitude of salinity reduction (pre-storm: 30‰, reduced to 10 or 15‰) and the timing of salinity reduction relative to life stage (naupliar, copepodite, adult). Survival and fecundity decreased with salinity reductions of greater magnitude and with exposure during earlier life stages. An age-classified Leslie matrix model constructed using these data predicted lower population growth rates with exposure to salinity reduction of greater magnitude or during an earlier life stage, although this trend was not significant.