Contrasting strategies to cope with storm‐induced erosion events: a flume study comparing a native vs. introduced bivalve

Abstract

Storm-induced erosion events may alter the diversity of tidal flat communities by selecting species that can better tolerate such disturbances. Introduced and invasive species are highly adaptable to a wide range of abiotic characteristics, and this adaptability may make them better able to withstand erosion events. With a novel flume method, we compared the ability of two bivalve species to resist storm-induced erosion: Cerastoderma edule, a native species to the Scheldt estuary in the Netherlands, and Ruditapes philippinarum, an introduced species that is successful in the Netherlands and worldwide. We used three sediment erosion rates to simulate storms of increasing severity. At the 10.6 and 15.9 cm h À1 sediment erosion rates, all R. philippinarum were surfaced, whereas only half C. edule were surfaced. However, after being brought to the sediment surface, C. edule were more readily transported by currents and waves than R. philippinarum due to differences in their shell shape. We concluded that the two bivalve species had different strategies to avoid mortality by severe storm erosion: C. edule avoided being surfaced and R. philippinarum avoided being transported. In this case, it appears that extreme storms favor the specific adaptations of a native species over the broad adaptability of a non-indigenous one. Indeed, C. edule may be more likely to survive moderately extreme storms than R. philippinarum, though the most extreme storms would be equally devastating to both species.

Weathering the storm

“…All experiments were conducted in a custom-made flume, containing a sediment core that could be pushed up with a pneumatic pump through a 16 cm diameter hole in the bottom of the flume. Given that the sediment core directly erodes as soon as the sediment enters the 40 cm/s flow in the flume, the erosion rate that animals in the sediment core experiences is equal to the rate by which the core was pushed into the flume (Wiesebron et al 2022). For animals to withstand erosion, they must thus either have a very deep initial burying depth or actively burrow down into the sediment with the same speed as the core is being pushed into the flume: 10 cm/h.…”

“…The erosion rate of at least 10 cm/h was chosen as a realistic high-end erosion rate, given that 10 to 15 cm of sediment erosion has been observed during a single storm-affected high-tide (Hu et al 2017, de Vet et al 2020. See Wiesebron et al (2022) for a more detailed description of the flume.…”

Benthic macrofauna under extremes

“…Benthic macrofauna can indicate habitat conditions due to their sedentary living style and sensitivity to physical or chemical disturbance (Donadi et al, 2015;Sukumaran et al, 2021). The current climate change scenarios are threatening the macrofauna by enhanced environmental disturbances in multiple abiotic factors such as temperature (Helmuth et al, 2002), hydrodynamics (Cahoon, 2006), sediment dynamics (Wiesebron et al, 2022;Zhou, Wu, et al, 2022), salinity (Debortoli et al, 2017), etc.…”