Permeability of coastal biogeographic barriers to marine larval dispersal on the east and west coasts of North America

Abstract

Aim We assess the role of contemporary oceanography and species traits in shaping observed patterns of biogeography over broad spatial scales. Location Our study domain covers the east and west coasts of North America, from 30° to 73° N on the east coast and 33° to 73° N on the west coast. Time period Hydrodynamic models use climatological fields from 1990 to 2015 on the east coast, and 1993 to 2018 on the west coast. Major taxa studied Model simulations represent larval dispersal for generalized benthic invertebrate species distributed in the subtidal zone from 10 to 100 m depth, with planktonic larval durations ranging from 21–60 days. Methods We conducted a literature review to identify major biogeographic barriers along the east and west coasts of North America, and then assessed the permeability of these barriers to larval dispersal using Lagrangian particle tracking. We ran a series of simulations in which we varied the suitable habitat distribution, planktonic larval duration, and spawning seasonality of simulated larvae (i.e., particles) to assess the effects of species traits on biogeography. Results Our results showed a strong alignment of observed biogeographic barriers with larval dispersal patterns, with high variation in barrier permeability depending on the traits of the species considered. The location of suitable habitat and the season during which particle release occurred were the biological traits that drove much of the variation in barrier permeability among simulations on both coasts. Main conclusions Our results indicate an important role of contemporary oceanographic and geographic features in determining the biogeography of species whose primary dispersal is during larval stages, suggesting that climate change is likely to alter patterns of species biogeography. Our results also demonstrate that species traits play a strong role in determining the location and strength of biogeographic barriers.

Opposing genetic patterns of range shifting temperate and tropical gastropods in an area undergoing tropicalisation

“…Grismer, 2002; Riddle et al., 2000). Here, we focus only on upwelling and large habitat gaps as potential barriers to gene flow (Fenberg et al., 2015; Knutsen et al., 2022; Krumhansl et al., 2023), as these have implications on coastal marine populations currently experiencing tropicalisation. However, we explore historical vicariant events and the phylogeographic patterns of our studied gastropods in the Supporting Information (Data S1).…”

“…Both upwelling (Fenberg et al., 2015) and large habitat gaps (Knutsen et al., 2022; Krumhansl et al., 2023) can create barriers to larval dispersal. Habitat availability and fragmentation affect dispersal success of plants and animals and consequently influence genetic diversity (Gibbs, 2001; Wort et al., 2019).…”