Refining expectations for environmental characteristics of refugia: two ranges of differing elevation and topographical complexity are mesic refugia in an arid landscape

M Byrne, DJ Coates, B MacDonald, S McArthur, M Zhou, MA Millar, SJ van Leeuwen

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Aim: Topographically complex areas are hypothesized to be mesic refugia in arid environments during periods of climatic change. We tested the hypothesis that an elevated and topographically complex range has been a historical refugium in an arid environment during Pleistocene climatic oscillations for a widespread eucalypt.
Location: Pilbara region, north-west Australia.
Methods: We evaluated genetic diversity and differentiation in chloroplast and nuclear genomes using microsatellite loci in 20 populations of Eucalyptus leucophloia from across the distribution in the Pilbara bioregion, including two ranges with differing topographical complexity and elevation. We evaluated phylogeographical structure using Permut and Network analysis, and assessed genetic structure using principle coordinate (PCoA) and Bayesian analyses.
Results: We found moderate levels of genetic diversity and low genetic differentiation among populations, typical of widespread eucalypts. There was no evidence of genetic structure across the sampled range. Populations in both the Hamersley and Chichester ranges showed higher levels of chloroplast haplotype and nuclear diversity than those in surrounding areas. Diversity was negatively correlated with evapotranspiration, and positively correlated with precipitation.
Main conclusions: Genetic signals of high diversity and low differentiation indicated population persistence throughout historical climate change in ranges, with a signal of expansion in surrounding areas. Our analysis was consistent with the hypothesis of the elevated, topographically complex Hamersley Range acting as a refugium, but revealed an unexpected result of the lower elevation, less rugged Chichester Range also being a refugium. Our results suggest refinement to expectations of environmental characteristics that facilitate persistence, where thresholds of mesic environments for refugia may be lower than expected and moisture availability may be an important contributory aspect of elevation and topographical complexity. In contrast to patterns in reptile species, lack of genetic structure associated with geological substrate and geomorphological features indicates dispersal is not impeded by these landscape features for this widespread eucalypt.
Original languageEnglish
Pages (from-to)2539-2550
Number of pages12
JournalJournal of Biogeography
Volume44
DOIs
Publication statusPublished - 2017
Externally publishedYes

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refining
refugium
refuge habitats
genetic structure
genetic variation
dry environmental conditions
arid environment
chloroplast
genetic differentiation
persistence
climate change
geomorphological feature
network analysis
reptile
nuclear genome
Eucalyptus
reptiles
evapotranspiration
oscillation
haplotypes

Cite this

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title = "Refining expectations for environmental characteristics of refugia: two ranges of differing elevation and topographical complexity are mesic refugia in an arid landscape",
abstract = "Aim: Topographically complex areas are hypothesized to be mesic refugia in arid environments during periods of climatic change. We tested the hypothesis that an elevated and topographically complex range has been a historical refugium in an arid environment during Pleistocene climatic oscillations for a widespread eucalypt. Location: Pilbara region, north-west Australia. Methods: We evaluated genetic diversity and differentiation in chloroplast and nuclear genomes using microsatellite loci in 20 populations of Eucalyptus leucophloia from across the distribution in the Pilbara bioregion, including two ranges with differing topographical complexity and elevation. We evaluated phylogeographical structure using Permut and Network analysis, and assessed genetic structure using principle coordinate (PCoA) and Bayesian analyses. Results: We found moderate levels of genetic diversity and low genetic differentiation among populations, typical of widespread eucalypts. There was no evidence of genetic structure across the sampled range. Populations in both the Hamersley and Chichester ranges showed higher levels of chloroplast haplotype and nuclear diversity than those in surrounding areas. Diversity was negatively correlated with evapotranspiration, and positively correlated with precipitation. Main conclusions: Genetic signals of high diversity and low differentiation indicated population persistence throughout historical climate change in ranges, with a signal of expansion in surrounding areas. Our analysis was consistent with the hypothesis of the elevated, topographically complex Hamersley Range acting as a refugium, but revealed an unexpected result of the lower elevation, less rugged Chichester Range also being a refugium. Our results suggest refinement to expectations of environmental characteristics that facilitate persistence, where thresholds of mesic environments for refugia may be lower than expected and moisture availability may be an important contributory aspect of elevation and topographical complexity. In contrast to patterns in reptile species, lack of genetic structure associated with geological substrate and geomorphological features indicates dispersal is not impeded by these landscape features for this widespread eucalypt.",
author = "M Byrne and DJ Coates and B MacDonald and S McArthur and M Zhou and MA Millar and {van Leeuwen}, SJ",
year = "2017",
doi = "10.1111/jbi.13057",
language = "English",
volume = "44",
pages = "2539--2550",
journal = "Journal of Biogeography",
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Refining expectations for environmental characteristics of refugia: two ranges of differing elevation and topographical complexity are mesic refugia in an arid landscape. / Byrne, M; Coates, DJ; MacDonald, B; McArthur, S; Zhou, M; Millar, MA; van Leeuwen, SJ.

In: Journal of Biogeography, Vol. 44, 2017, p. 2539-2550.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Refining expectations for environmental characteristics of refugia: two ranges of differing elevation and topographical complexity are mesic refugia in an arid landscape

AU - Byrne, M

AU - Coates, DJ

AU - MacDonald, B

AU - McArthur, S

AU - Zhou, M

AU - Millar, MA

AU - van Leeuwen, SJ

PY - 2017

Y1 - 2017

N2 - Aim: Topographically complex areas are hypothesized to be mesic refugia in arid environments during periods of climatic change. We tested the hypothesis that an elevated and topographically complex range has been a historical refugium in an arid environment during Pleistocene climatic oscillations for a widespread eucalypt. Location: Pilbara region, north-west Australia. Methods: We evaluated genetic diversity and differentiation in chloroplast and nuclear genomes using microsatellite loci in 20 populations of Eucalyptus leucophloia from across the distribution in the Pilbara bioregion, including two ranges with differing topographical complexity and elevation. We evaluated phylogeographical structure using Permut and Network analysis, and assessed genetic structure using principle coordinate (PCoA) and Bayesian analyses. Results: We found moderate levels of genetic diversity and low genetic differentiation among populations, typical of widespread eucalypts. There was no evidence of genetic structure across the sampled range. Populations in both the Hamersley and Chichester ranges showed higher levels of chloroplast haplotype and nuclear diversity than those in surrounding areas. Diversity was negatively correlated with evapotranspiration, and positively correlated with precipitation. Main conclusions: Genetic signals of high diversity and low differentiation indicated population persistence throughout historical climate change in ranges, with a signal of expansion in surrounding areas. Our analysis was consistent with the hypothesis of the elevated, topographically complex Hamersley Range acting as a refugium, but revealed an unexpected result of the lower elevation, less rugged Chichester Range also being a refugium. Our results suggest refinement to expectations of environmental characteristics that facilitate persistence, where thresholds of mesic environments for refugia may be lower than expected and moisture availability may be an important contributory aspect of elevation and topographical complexity. In contrast to patterns in reptile species, lack of genetic structure associated with geological substrate and geomorphological features indicates dispersal is not impeded by these landscape features for this widespread eucalypt.

AB - Aim: Topographically complex areas are hypothesized to be mesic refugia in arid environments during periods of climatic change. We tested the hypothesis that an elevated and topographically complex range has been a historical refugium in an arid environment during Pleistocene climatic oscillations for a widespread eucalypt. Location: Pilbara region, north-west Australia. Methods: We evaluated genetic diversity and differentiation in chloroplast and nuclear genomes using microsatellite loci in 20 populations of Eucalyptus leucophloia from across the distribution in the Pilbara bioregion, including two ranges with differing topographical complexity and elevation. We evaluated phylogeographical structure using Permut and Network analysis, and assessed genetic structure using principle coordinate (PCoA) and Bayesian analyses. Results: We found moderate levels of genetic diversity and low genetic differentiation among populations, typical of widespread eucalypts. There was no evidence of genetic structure across the sampled range. Populations in both the Hamersley and Chichester ranges showed higher levels of chloroplast haplotype and nuclear diversity than those in surrounding areas. Diversity was negatively correlated with evapotranspiration, and positively correlated with precipitation. Main conclusions: Genetic signals of high diversity and low differentiation indicated population persistence throughout historical climate change in ranges, with a signal of expansion in surrounding areas. Our analysis was consistent with the hypothesis of the elevated, topographically complex Hamersley Range acting as a refugium, but revealed an unexpected result of the lower elevation, less rugged Chichester Range also being a refugium. Our results suggest refinement to expectations of environmental characteristics that facilitate persistence, where thresholds of mesic environments for refugia may be lower than expected and moisture availability may be an important contributory aspect of elevation and topographical complexity. In contrast to patterns in reptile species, lack of genetic structure associated with geological substrate and geomorphological features indicates dispersal is not impeded by these landscape features for this widespread eucalypt.

U2 - 10.1111/jbi.13057

DO - 10.1111/jbi.13057

M3 - Article

VL - 44

SP - 2539

EP - 2550

JO - Journal of Biogeography

JF - Journal of Biogeography

SN - 0305-0270

ER -