Bernardo R. Broitman1, Marco A. Lardies1, Mauricio H. Oróstica2, Nicolás I. Segovia3, Pilar A. Haye3
1Universidad Adolfo Ibañez, Chile - 2Universidad Católica del Maule, Chile - 3Universidad Católica del Norte, Chile
A marine biogeographic and phylogeographic break located around 30°S on the shores of the southeastern Pacific coincides with a mesoscale change in coastal upwelling regime. Prior ecological and genetic evidence indicated that dispersal limitation was the leading mechanism maintaining the break. Mounting evidence of large between-site environmental heterogeneity along the transitional zone provides support for a niche-based mechanism as the underlying driver. To test this hypothesis, we examined patterns of phenotypic plasticity under contrasting thermal conditions for species belonging to multiple benthic taxa and different trophic levels, from multiple populations spanning the biogeographic break. We pooled our plasticity estimations with data from similar studies across the region and examined their joint spatial structure and its relationship with environmental heterogeneity. We observed that regardless of taxa and trophic level, individuals from populations within the biogeographic break showed higher phenotypic plasticity. Similarly, the spatial structure in neutral genetic markers for this diverse set of benthic species, which either spanned the transition zone or found the edge of their geographic ranges around it, hints at the presence of local adaptation. Our results suggest that evolutionary novel ecological interactions occur under environmental conditions that challenge species’ physiological limits. The species that span the transition zone are likely to persist locally only through a net influx of propagules. The strong selective pressure identified by the spatial structure of phenotypical plasticity and phylogeographic patterns across multiple species suggest that the region may represent an area of special interest for future conservation efforts. Moreover, similar eco-evolutionary patterns may be a common feature in other coastal regions
Biography
Bernardo is an ecologist interested in the linkages between organismal perfomance, its environmental drivers and the impacts of that interaction on population and community dynamics over large spatial and temporal scales. He has a focus on coastal communities in upwelling systems worldwide, with most of his work in the temperate section of the Humboldt system. He is based in Viña del Mar Chile.