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Publication
Pleistocene expansion, anthropogenic pressure and ocean currents: Disentangling the past and ongoing evolutionary history of Patella aspera Röding, 1798 in the archipelago of Madeira
Advisor(s)
Abstract(s)
Aims: Rising sea-level following the Last Glacial Maximum lead to fragmentation of coastal limpet populations
between islands of the Archipelago of Madeira. This fragmentation is reinforced by recent heavy exploitation
reducing effective population size on Madeira Island. We use the limpet P. aspera to understand how the role of
processes at different time scales (i.e. changes in the sea level and overexploitation) can influence the genetic
composition of an extant species, relating these processes to reproductive phenology and seasonal shifts in ocean
currents.
Location: Madeira Island, Porto Santo and Desertas (Archipelago of Madeira, NE Atlantic Ocean).
Taxon: The limpet Patella aspera.
Methods: Twelve microsatellite genetic markers were used. A power analysis was used to evaluate the power of
the microsatellite markers to detect a signal of population differentiation. Long-term past migrations were
assessed using a Bayesian Markov Montecarlo approach in the software MIGRATE-n to estimate mutation-scaled
migration rates (M = m/μ; m, probability of a lineage immigrating per generation; μ, mutation rate). Two sce narios were evaluated using an Approximate Bayesian Computation (ABC) in the software DIYABC 2.1 (i) Sce nario 1: considered a population scenario from a reduced Ne at time t3 to a higher Ne at time t2; and (ii) Scenario
2 considering a reduction of Ne from a time t3 to a time t2.
Results: Colonization of the archipelago by Portuguese settlers six centuries ago probably led to an important
decrease in the genetic diversity of the species (Ne). Contemporary gene flow strongly support a pattern of high
asymmetric connectivity explained by the reproductive phenology of the species and spatio-temporal seasonal
changes in the ocean currents. Spatio-temporal reconstructions using Bayesian methods, including coalescent
and Approximate Bayesian Computation (ABC) approaches, suggest changes in the migration patterns from
highly symmetric to highly asymmetric connectivity with subtle population differentiation as consequence of
post-glacial maximum sea level rise during the Holocene.
Description
Keywords
Genetic markers Microsatellites Limpet Intertidal Island NE Atlantic ocean . Faculdade de Ciências da Vida
Citation
Sousa, R., Vasconcelos, J., Vera-Escalona, I., Pinto, A. R., Hawkins, S. J., Freitas, M., ... & Riera, R. (2021). Pleistocene expansion, anthropogenic pressure and ocean currents: disentangling the past and ongoing evolutionary history of Patella aspera Röding, 1798 in the archipelago of Madeira. Marine Environmental Research, 172, 105485. https://doi.org/10.1016/j.marenvres.2021.105485
Publisher
Elsevier