Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?

Aim: Understanding how landscape features affect gene flow is critical to connectivity conservation and restoration management. Here, we examined the relationship between functional connectivity (gene flow) and structural connectivity (area and spatial configuration of habitats) in three co-occurrin...

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Main Authors: Nevill, Paul, Robinson, Todd, Di Virgilio, Giovanni, Wardell-Johnson, Grant
Format: Journal Article
Language:English
Published: WILEY 2019
Subjects:
Online Access:http://purl.org/au-research/grants/arc/IC150100041
http://hdl.handle.net/20.500.11937/88513
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author Nevill, Paul
Robinson, Todd
Di Virgilio, Giovanni
Wardell-Johnson, Grant
author_facet Nevill, Paul
Robinson, Todd
Di Virgilio, Giovanni
Wardell-Johnson, Grant
author_sort Nevill, Paul
building Curtin Institutional Repository
collection Online Access
description Aim: Understanding how landscape features affect gene flow is critical to connectivity conservation and restoration management. Here, we examined the relationship between functional connectivity (gene flow) and structural connectivity (area and spatial configuration of habitats) in three co-occurring short-range plant taxa in an ancient terrestrial island system. Location: Low-altitude mountain range south-western Australia. Methods: We analysed spatial patterns of genetic differentiation at nuclear microsatellite loci using Bayesian clustering. Circuit theory modelling was used to generate all possible pathways that connect populations as resistance distance matrices based on two surfaces for each taxon. The first surface assumes a flat terrain and tests whether genetic similarity declines only with distance—isolation by distance (IBD). The second surface is habitat suitability based on species distribution modelling (SDM), which tests whether genetic similarity is a function of connected and suitable habitat. Multiple matrix regression with randomization was used to test the significance of the resistance distance matrices at predicting two metrics of genetic differentiation (FST and DEST). Variance explained was partitioned using redundancy analysis. Results: Genetic structure for the insect-pollinated taxa—Acacia adinophylla—and Tetratheca aphylla subsp. aphylla was at similar spatial scales. Unexpectedly, a higher level of genetic structure was found in the wind-pollinated Lepidosperma bungalbin. IBD best explained the gene flow of A. adinophylla (R2 = 0.41–0.43) with partial support provided by habitat suitability (R2 = 0.04–0.07). In contrast, connectivity by habitat suitability was highest for T. aphylla subsp. aphylla (R2 = 0.56–0.59). Drivers of L. bungalbin connectivity were inconsistent between the two measures of genetic differentiation. Main conclusions: Gene flow is facilitated by different factors for the three taxa. Habitat fragmentation would most strongly impede gene flow for T. aphylla subsp. aphylla. Geographical distance cannot be assumed as the sole or best determinant of gene flow among populations, nor can findings be generalized to coexisting taxa.
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spelling curtin-20.500.11937-885132022-08-22T04:21:41Z Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system? Nevill, Paul Robinson, Todd Di Virgilio, Giovanni Wardell-Johnson, Grant Science & Technology Life Sciences & Biomedicine Biodiversity Conservation Ecology Biodiversity & Conservation Environmental Sciences & Ecology banded ironstone formations circuit theory gene flow habitat conservation IBD inselbergs landscape connectivity landscape genetics restoration planning GENETIC DIVERSITY HABITAT FRAGMENTATION TETRATHECA ELAEOCARPACEAE FORMERLY TREMANDRACEAE IRONSTONE OUTCROPS COMPUTER-PROGRAM LANDSCAPE SOFTWARE CONSEQUENCES DISPERSAL Aim: Understanding how landscape features affect gene flow is critical to connectivity conservation and restoration management. Here, we examined the relationship between functional connectivity (gene flow) and structural connectivity (area and spatial configuration of habitats) in three co-occurring short-range plant taxa in an ancient terrestrial island system. Location: Low-altitude mountain range south-western Australia. Methods: We analysed spatial patterns of genetic differentiation at nuclear microsatellite loci using Bayesian clustering. Circuit theory modelling was used to generate all possible pathways that connect populations as resistance distance matrices based on two surfaces for each taxon. The first surface assumes a flat terrain and tests whether genetic similarity declines only with distance—isolation by distance (IBD). The second surface is habitat suitability based on species distribution modelling (SDM), which tests whether genetic similarity is a function of connected and suitable habitat. Multiple matrix regression with randomization was used to test the significance of the resistance distance matrices at predicting two metrics of genetic differentiation (FST and DEST). Variance explained was partitioned using redundancy analysis. Results: Genetic structure for the insect-pollinated taxa—Acacia adinophylla—and Tetratheca aphylla subsp. aphylla was at similar spatial scales. Unexpectedly, a higher level of genetic structure was found in the wind-pollinated Lepidosperma bungalbin. IBD best explained the gene flow of A. adinophylla (R2 = 0.41–0.43) with partial support provided by habitat suitability (R2 = 0.04–0.07). In contrast, connectivity by habitat suitability was highest for T. aphylla subsp. aphylla (R2 = 0.56–0.59). Drivers of L. bungalbin connectivity were inconsistent between the two measures of genetic differentiation. Main conclusions: Gene flow is facilitated by different factors for the three taxa. Habitat fragmentation would most strongly impede gene flow for T. aphylla subsp. aphylla. Geographical distance cannot be assumed as the sole or best determinant of gene flow among populations, nor can findings be generalized to coexisting taxa. 2019 Journal Article http://hdl.handle.net/20.500.11937/88513 10.1111/ddi.12959 English http://purl.org/au-research/grants/arc/IC150100041 http://creativecommons.org/licenses/by/4.0/ WILEY fulltext
spellingShingle Science & Technology
Life Sciences & Biomedicine
Biodiversity Conservation
Ecology
Biodiversity & Conservation
Environmental Sciences & Ecology
banded ironstone formations
circuit theory
gene flow
habitat conservation
IBD
inselbergs
landscape connectivity
landscape genetics
restoration planning
GENETIC DIVERSITY
HABITAT FRAGMENTATION
TETRATHECA ELAEOCARPACEAE
FORMERLY TREMANDRACEAE
IRONSTONE OUTCROPS
COMPUTER-PROGRAM
LANDSCAPE
SOFTWARE
CONSEQUENCES
DISPERSAL
Nevill, Paul
Robinson, Todd
Di Virgilio, Giovanni
Wardell-Johnson, Grant
Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title_full Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title_fullStr Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title_full_unstemmed Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title_short Beyond isolation by distance: What best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
title_sort beyond isolation by distance: what best explains functional connectivity among populations of three sympatric plant species in an ancient terrestrial island system?
topic Science & Technology
Life Sciences & Biomedicine
Biodiversity Conservation
Ecology
Biodiversity & Conservation
Environmental Sciences & Ecology
banded ironstone formations
circuit theory
gene flow
habitat conservation
IBD
inselbergs
landscape connectivity
landscape genetics
restoration planning
GENETIC DIVERSITY
HABITAT FRAGMENTATION
TETRATHECA ELAEOCARPACEAE
FORMERLY TREMANDRACEAE
IRONSTONE OUTCROPS
COMPUTER-PROGRAM
LANDSCAPE
SOFTWARE
CONSEQUENCES
DISPERSAL
url http://purl.org/au-research/grants/arc/IC150100041
http://hdl.handle.net/20.500.11937/88513