The range expansion of Clibanarius erythropus to the UK suggests that other range-shifting intertidal species may not follow

Abstract

The ranges of species are shifting as a consequence of anthropogenic climate change. In the marine realm biogeographic transition zones could form barriers to dispersal and inhibit range-shift, but little is known about this potential effect. The hermit crab Clibanarius erythropus appeared in the UK in 2016 with the nearest reproducing population being on the northern coast of Brittany. This raises questions of which conditions may have permitted C. erythropus to cross the English Channel (7.25°W, 49.00°N) and whether this barrier could be overcome by other intertidal species. Dispersal simulations suggest the larvae of C. erythropus arrived in 2014, originated from North Brittany, experienced a mean temperature of around 16 °C, and took longer than 20 days to be transported across the channel. The transportation of larvae from Brittany to the southwest UK appears to be rare and driven by occasional, unusual ocean currents. The English Channel may continue to prevent species with pelagic larvae that settle within 20 days, such as many species of gastropod, annelids, and macroalgae, from successfully range expanding to the UK. North Brittany was the only landmass from which it is feasible the UK population of C. erythropus could have originated. Therefore, species with long-lived pelagic larvae but without reproducing populations in North Brittany may not appear in the southwest UK until the species are established in North Brittany. The English Channel could continue to limit the ability of many intertidal species to shift their range with climate change.

Two new hermit crab species ofDiogenes(Crustacea: Decapoda: Diogenidae) from Atlanto‐Mediterranean coasts of Iberian Peninsula: Poleward migrants or merely overlooked indigenous species?

“…The first hypothesis involves the migration of the species from Africa to Europe, a process known as tropicalization (Cuesta et al, 2016). It is well known that anthropogenic activities and climate change are among the most important factors that may enhance the establishment of introduced species, as well as the poleward shift in distribution of numerous species over decades (González‐Ortegón et al, 2020), even overcoming important geographic barriers under favorable conditions (Patterson et al, 2022). The Strait of Gibraltar area has an important role as a pathway of introductions both from the Mediterranean Sea and by West African biota moving northwards into European waters, the later labeled as “African Creep” by Canning‐Clode and Carlton (2017).…”

Rare, long‐distance dispersal underpins genetic connectivity in the pink sea fan, Eunicella verrucosa

“…This dispersal capacity accords with the relatively low genetic differentiation detected between these areas and is again suggestive of stepping-stone connectivity. Similarly, dispersal simulations for a species of hermit crab, Clibanarius erythropus, suggested that larval transport from Brittany, northwest France, to southwest Britain is rare but possible and results from unusual ocean currents, though the authors found the Channel may still act as a barrier to species with a larval PLD of less than 20 days (Patterson et al, 2022). Similarly, Ayata et al ( 2010) simulated particle dispersal trajectories with a 4-week PLD and showed successful dispersal across the Channel due to residual circulation under realistic hydrodynamic conditions.…”