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Advisor(s)
Abstract(s)
Aim: Species distributions have been continuously adjusting to changing climatic
conditions throughout the glacial–interglacial cycles. In the marine realm, evidence suggests that latitudinal range shifts, involving both spatial expansions and trailingedge contractions, may represent a common response to climatic oscillations. The biogeographical histories of coastal organisms, however, have been inferred
primarily using molecular markers, potentially overlooking past range dynamics
beyond contemporary rear edges. In this study we combined species distribution
models (SDMs) and mitochondrial DNA (mtDNA) data to investigate the biogeographical
history of the high-intertidal seaweed Pelvetia canaliculata. We investigated
the hypotheses that its distribution is set by both marine and terrestrial climates and that its range has shifted northwards since the Last Glacial Maximum. Location North-eastern Atlantic intertidal from Portugal to Norway.
Methods: In total, 432 individuals at 27 sites covering the extant range of Pelvetia
canaliculata were sampled and sequenced for a c. 500 bp mtDNA intergenic spacer. A niche model was developed using marine and terrestrial variables. Range dynamics were reconstructed based on the geographical patterns of genetic variation and on the SDM projections for the Last Glacial Maximum (LGM) and the present.
Results: The best distribution models incorporated both marine and terrestrial
variables. LGM projections revealed suitable habitat between southern Morocco and the periglacial shorelines of the Celtic Sea. Pelvetia canaliculata exhibited a highly structured phylogeography, being subdivided into three largely disjunct lineages, two of them endemic to Iberia. The central/northern European lineage exhibited the highest haplotypic diversity and showed a consistent decline in nucleotide diversity and haplotypic richness at higher latitudes.
Main conclusions: Assuming species/climate equilibrium, SDMs supported the hypothesis of a post-glacial latitudinal range shift. Molecular variation revealed contrasting demographic behaviours in Iberian and periglacial regions. In Iberia the low haplotypic diversity suggested complex range dynamics that are not fully captured by SDM projections. Periglacial regions, identified as the source of poleward colonization, were inferred to have been comparatively more stable. Greater attention should be paid to marine range dynamics at low-latitude range margins, particularly in genetically structured low-dispersal species exhibiting southern endemic variation.
Description
Keywords
Climatic refugia Last Glacial Maximum North-eastern Atlantic Pelvetia canaliculata Phylogeography Range shift Species distribution model Trailing-edge
Pedagogical Context
Citation
Neiva, J.; Assis, J.F.; Fernandes, F.; Pearson, G.A.; Serrão, E.A. Species distribution models and mitochondrial DNA phylogeography suggest an extensive biogeographical shift in the high-intertidal seaweed Pelvetia canaliculata, Journal of Biogeography, 41, 1137-1148, 2014.
Publisher
Wiley