Local Scale Thermal Environment and Limited Gene Flow Indicates Vulnerability of Warm Edge Populations in a Habitat Forming Macroalga

Clark, JS; Poore, AGB; Coleman, MA; Doblin, MA

Local Scale Thermal Environment and Limited Gene Flow Indicates Vulnerability of Warm Edge Populations in a Habitat Forming Macroalga

Clark, JS Poore, AGB Coleman, MA Doblin, MA

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Publisher:: FRONTIERS MEDIA SA
Publication Type:: Journal Article
Citation:: Frontiers in Marine Science, 2020, 7
Issue Date:: 2020-08-27

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Field	Value	Language
dc.contributor.author	Clark, JS
dc.contributor.author	Poore, AGB
dc.contributor.author	Coleman, MA
dc.contributor.author	Doblin, MA
dc.date.accessioned	2020-12-11T00:39:15Z
dc.date.available	2020-12-11T00:39:15Z
dc.date.issued	2020-08-27
dc.identifier.citation	Frontiers in Marine Science, 2020, 7
dc.identifier.issn	2296-7745
dc.identifier.issn	2296-7745
dc.identifier.uri	http://hdl.handle.net/10453/144630
dc.description.abstract	© Copyright © 2020 Clark, Poore, Coleman and Doblin. Species inhabiting warm-edge populations of their distribution are suggested to be at the forefront of global warming due to reduced fitness, limited gene flow and living close to their physiological thermal limits. Determining the scale that governs thermal niche and the functional responses of habitat-forming species to environmental stressors is critical for successful conservation efforts, particularly as coastal ecosystems are impacted by global change. Here, we examine the susceptibility of warm-edge populations to warming, in the habitat-forming macroalga, Hormosira banksii, from south-eastern Australia. We use a quantitative breeding design to quantify intraspecific variation in thermal performance (growth, ontogenic development and photosynthetic efficiency) of different genotypes sourced from sites at the equatorward distributional edge (warm-edge) and those toward the center of its distribution (non-edge). The genetic diversity and structure of H. banksii was also examined using microsatellite markers amongst the same sites. Our results found variable responses in thermal performance for growth and development. Warm-edge germlings grew optimally in lower temperatures tested and had narrower thermal breadth compared to non-edge germlings which grew in higher and more broader temperatures. Warm-edge germlings however, showed greater plasticity to tolerate high light indicated by a greater proportion of energy being dissipated as regulated non-photochemical quenching [Y(NPQ)] than non-regulated non-photochemical quenching [Y(NO)]. Overall genetic diversity was lower at the warm-edge location with evidence of increased structuring and reduced gene flow in comparison to the non-edge location. Evidence of genetic structuring was not found locally between high and low shore within sites. Together, these data suggest that non-edge populations may be “thermally buffered” from increased temperatures associated with ocean warming. Warm-edge populations of H. banksii, however, may be vulnerable to warming, due to narrower thermal breadth and sensitivity to higher temperatures, with genetic impoverishment through loss of individuals likely to further reduce population viability.
dc.language	English
dc.publisher	FRONTIERS MEDIA SA
dc.relation.ispartof	Frontiers in Marine Science
dc.relation.isbasedon	10.3389/fmars.2020.00711
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	Copyright © 2020 Clark, Poore, Coleman and Doblin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
dc.subject	0405 Oceanography, 0602 Ecology
dc.title	Local Scale Thermal Environment and Limited Gene Flow Indicates Vulnerability of Warm Edge Populations in a Habitat Forming Macroalga
dc.type	Journal Article
utslib.citation.volume	7
utslib.for	0405 Oceanography
utslib.for	0602 Ecology
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
pubs.organisational-group	/University of Technology Sydney
utslib.copyright.status	open_access	*
dc.date.updated	2020-12-11T00:39:09Z
pubs.publication-status	Published
pubs.volume	7

Abstract:

© Copyright © 2020 Clark, Poore, Coleman and Doblin. Species inhabiting warm-edge populations of their distribution are suggested to be at the forefront of global warming due to reduced fitness, limited gene flow and living close to their physiological thermal limits. Determining the scale that governs thermal niche and the functional responses of habitat-forming species to environmental stressors is critical for successful conservation efforts, particularly as coastal ecosystems are impacted by global change. Here, we examine the susceptibility of warm-edge populations to warming, in the habitat-forming macroalga, Hormosira banksii, from south-eastern Australia. We use a quantitative breeding design to quantify intraspecific variation in thermal performance (growth, ontogenic development and photosynthetic efficiency) of different genotypes sourced from sites at the equatorward distributional edge (warm-edge) and those toward the center of its distribution (non-edge). The genetic diversity and structure of H. banksii was also examined using microsatellite markers amongst the same sites. Our results found variable responses in thermal performance for growth and development. Warm-edge germlings grew optimally in lower temperatures tested and had narrower thermal breadth compared to non-edge germlings which grew in higher and more broader temperatures. Warm-edge germlings however, showed greater plasticity to tolerate high light indicated by a greater proportion of energy being dissipated as regulated non-photochemical quenching [Y(NPQ)] than non-regulated non-photochemical quenching [Y(NO)]. Overall genetic diversity was lower at the warm-edge location with evidence of increased structuring and reduced gene flow in comparison to the non-edge location. Evidence of genetic structuring was not found locally between high and low shore within sites. Together, these data suggest that non-edge populations may be “thermally buffered” from increased temperatures associated with ocean warming. Warm-edge populations of H. banksii, however, may be vulnerable to warming, due to narrower thermal breadth and sensitivity to higher temperatures, with genetic impoverishment through loss of individuals likely to further reduce population viability.

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