A multispecies, multitrophic genomics approach to coastal ecosystem structure

Informations

Funding country

Norway

Acronym

ECOGENOME

URL

-

Start date

1/1/2018

End date

12/31/2022

Budget

1,068,378 EUR

Fundings

Abstract

This multidisciplinary project addressed the fundamental question of how the ecosystem and species along the coast are structured spatially and what is the appropriate scale of management of coastal ecosystems. We applied genomic tools (ddRAD and full-genome re-sequencing) and characterized how genetic variability is structured spatially within a sample of coastal species, covering all trophic levels from primary producers to top predators and sampled from the same locations. On the largest geographic scale (~1000km) we found a marked genetic discontinuity or "genetic break" that occurred at the same geographic location (near Jæren) across multiple species, implying low or negligible connectivity across this location. Full-genome data did not reveal any important role of natural selection in explaining this genetic break, which instead appears to be caused by local oceanographic features and a lack of suitable habitats together restrict connectivity and gene flow within species. On the finer geographic scale (~100km) we detected no or only weak genetic structure that took the form of a linear increase in differentiation with distance. This pattern matches expectations of moderate along-coast connectivity that declines with geographic distance, reflecting limited mobility in many coastal species. For the Norwegian Skagerrak coast we were able to supplement these population genomic analyses with spatial population dynamical analyses of an unique long-term beach seine survey. Temporal variability in population density, as reflected in annual beach seine catches, displayed a spatial synchrony pattern with exponentially declining correlations with distance along the coast, consistent with moderate connectivity on this geographic scale. In summary, the project uncovered regional genetic clustering in multiple species superimposed on a general pattern of limited population connectivity along the coastline. These findings imply that management of the coastal sone and its biodivesity can benefit, first, from separating the coast into regions defined by genetic break zones and, second, by appreciation of limited population connectivity also within regions.