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Byrne M, Ramalho CE, Tapper S, Coates DJ. Topographic Complexity Facilitates Persistence Compared to Signals of Contraction and Expansion in the Adjacent Subdued Landscape. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.833766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Topographically heterogeneous areas are likely to act as refugia for species because they facilitate survival during regional climatic stress due to availability of a range of microenvironments. The Stirling Ranges are a topographically complex area in the generally subdued and ancient landscape of south-western Australia. We investigated the influence of these landscape features on the evolutionary history of the rare woody shrub, Banksia brownii through a combined approach using phylogeographic analysis of sequence data from three chloroplast sequences, the trnV–ndhC, trnQ–rps16, and rpl32–ndhF intergenic spacer regions, and species distribution modeling. The Stirling Ranges showed high genetic diversity and differentiation among populations consistent with localized persistence and maintenance of large populations in an area that species distribution modeling identified as providing habitat stability at the Last Glacial Maximum as well as under warmer conditions. In contrast, populations in the adjacent subdued lowlands showed signals of low diversity, suggesting contraction, and subsequent expansion from localized refugia in the west. Cool summers are an important climatic variable for the species and species distribution modeling showed suitable habitat identified at the LGM suggesting expansion at this time following likely contraction during earlier warmer climatic oscillations. The isolated, coastal population at Vancouver Peninsula showed low diversity but no differentiation and it may have been established in more recent historical times, possibly through Aboriginal movement of seed. Our analysis of B. brownii highlights the complex evolutionary history of the species and the influence of topographic complexity and habitat heterogeneity in this global biodiversity hotspot.
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Binks RM, Steane DA, Byrne M. Genomic divergence in sympatry indicates strong reproductive barriers and cryptic species within Eucalyptus salubris. Ecol Evol 2021; 11:5096-5110. [PMID: 34025994 PMCID: PMC8131811 DOI: 10.1002/ece3.7403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/26/2022] Open
Abstract
Genetic studies are increasingly detecting cryptic taxa that likely represent a significant component of global biodiversity. However, cryptic taxa are often criticized because they are typically detected serendipitously and may not receive the follow-up study required to verify their geographic or evolutionary limits. Here, we follow-up a study of Eucalyptus salubris that unexpectedly detected two divergent lineages but was not sampled sufficiently to make clear interpretations. We undertook comprehensive sampling for an independent genomic analysis (3,605 SNPs) to investigate whether the two purported lineages remain discrete genetic entities or if they intergrade throughout the species' range. We also assessed morphological and ecological traits, and sequenced chloroplast DNA. SNP results showed strong genome-wide divergence (F ST = 0.252) between two discrete lineages: one dominated the north and one the southern regions of the species' range. Within lineages, gene flow was high, with low differentiation (mean F ST = 0.056) spanning hundreds of kilometers. In the central region, the lineages were interspersed but maintained their genomic distinctiveness: an indirect demonstration of reproductive isolation. Populations of the southern lineage exhibited significantly lower specific leaf area and occurred on soils with lower phosphorus relative to the northern lineage. Finally, two major chloroplast haplotypes were associated with each lineage but were shared between lineages in the central distribution. Together, these results suggest that these lineages have non-contemporary origins and that ecotypic adaptive processes strengthened their divergence more recently. We conclude that these lineages warrant taxonomic recognition as separate species and provide fascinating insight into eucalypt speciation.
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Affiliation(s)
- Rachel M. Binks
- Biodiversity and Conservation ScienceDepartment of Biodiversity, Conservation and AttractionsBentley Delivery CentreBentleyWAAustralia
| | - Dorothy A. Steane
- School of Natural Sciences and ARC Training Centre for Forest ValueUniversity of TasmaniaHobartTasmaniaAustralia
- CSIRO Land and WaterSandy BayTasmaniaAustralia
| | - Margaret Byrne
- Biodiversity and Conservation ScienceDepartment of Biodiversity, Conservation and AttractionsBentley Delivery CentreBentleyWAAustralia
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Nistelberger HM, Tapper S, Coates DJ, McArthur SL, Byrne M. As old as the hills: Pliocene palaeogeographical processes influence patterns of genetic structure in the widespread, common shrub Banksia sessilis. Ecol Evol 2021; 11:1069-1082. [PMID: 33520187 PMCID: PMC7820165 DOI: 10.1002/ece3.7127] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 11/04/2020] [Accepted: 11/25/2020] [Indexed: 11/12/2022] Open
Abstract
The impact of Quaternary glaciation on the development of phylogeographic structure in plant species is well documented. In unglaciated landscapes, phylogeographic patterns tend to reflect processes relating to persistence and stochasticity, yet other factors, associated with the palaeogeographical history of the landscape, including geomorphological events, can also have a significant influence. The unglaciated landscape of south-western Western Australia is an ideal location to observe these ancient drivers of lineage diversification, with tectonic activity associated with the Darling Fault in the late Pliocene attributed to patterns of deep phylogeographic divergence in a widespread tree from this region. Interestingly, other species within this region have not shown this pattern and this palaeogeographical boundary therefore presents an opportunity to examine age and historical distribution of plant species endemic to this region. In this study, we assess patterns of genetic diversity and structure across 28 populations of the widespread shrub Banksia sessilis using three cpDNA markers and nine nuclear microsatellite markers. Sixteen cpDNA haplotypes were identified, comprising two major chloroplast DNA lineages that are estimated to have diverged in the Pliocene, approximately 3.3 million years ago. This timing coincides with major geomorphological processes in the landscape, including the separation of the Darling Plateau from the adjacent Swan Coastal Plain, as well as eustatic changes on the Swan Coastal Plain that are likely to have resulted in the physical isolation of historical plant lineages. Chloroplast lineages were broadly aligned with populations associated with older lateritic soils of the Darling Plateau and Geraldton sandplains or the younger sandy soils associated with the Swan Coastal Plain and Southern Coastline. This structural pattern of lateritic versus non-lateritic division was not observed in the nuclear microsatellite data that identified three genetic clades that roughly corresponded to populations in the North, South, and Central portions of the distributions.
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Affiliation(s)
- Heidi Maria Nistelberger
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation ScienceBentleyWAAustralia
| | - Sarah‐Louise Tapper
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation ScienceBentleyWAAustralia
| | - David J. Coates
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation ScienceBentleyWAAustralia
| | - Shelley L. McArthur
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation ScienceBentleyWAAustralia
| | - Margaret Byrne
- Department of Biodiversity, Conservation and AttractionsBiodiversity and Conservation ScienceBentleyWAAustralia
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Gosper CR, Kinloch J, Coates DJ, Byrne M, Pitt G, Yates CJ. Differential exposure and susceptibility to threats based on evolutionary history: how OCBIL theory informs flora conservation. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Optimal conservation approaches have been proposed to differ for biota with contrasting evolutionary histories. Natural selection filters the distribution of plant traits over evolutionary time, with the current expression of traits mediating susceptibility to contemporary and often novel threats. We use old, climatically buffered, infertile landscape (OCBIL) theory to compile predictions regarding differences in exposure and susceptibility to key threats between OCBIL and young, often disturbed, fertile landscape (YODFEL) flora. Based on literature and existing data from the Southwest Australian Floristic Region (SWAFR), we evaluate evidence in support of our predictions, finding strong theoretical and empirical support for the proposition that exposure and/or impact of many threats differs between OCBILs and YODFELs. OCBILs have more exposure to land clearance from mining, whereas many YODFELs have greater exposure to land clearance from agriculture, and urban and industrial land uses, and greater overall levels of habitat loss and fragmentation. OCBIL flora are more susceptible to pathogens and extremes of fire interval than YODFEL flora, but conversely may have a greater capacity to persist in smaller populations if small populations featured in the evolutionary history of the species prior to anthropogenic fragmentation, and have substantial resistance to weed invasion. We argue that consideration of evolutionary history has an important role in informing conservation management.
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Affiliation(s)
- Carl R Gosper
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Janine Kinloch
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - David J Coates
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Margaret Byrne
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Georgie Pitt
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Colin J Yates
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
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Nistelberger HM, Binks RM, van Leeuwen S, Coates DJ, McArthur SL, Macdonald BM, Hankinson M, Byrne M. Extensive Genetic Connectivity and Historical Persistence Are Features of Two Widespread Tree Species in the Ancient Pilbara Region of Western Australia. Genes (Basel) 2020; 11:E863. [PMID: 32751318 PMCID: PMC7465080 DOI: 10.3390/genes11080863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 11/29/2022] Open
Abstract
Phylogeographic studies can be used as a tool to understand the evolutionary history of a landscape, including the major drivers of species distributions and diversity. Extensive research has been conducted on phylogeographic patterns of species found in northern hemisphere landscapes that were affected by glaciations, yet the body of literature for older, unaffected landscapes is still underrepresented. The Pilbara region of north-western Australia is an ancient and vast landscape that is topographically complex, consisting of plateaus, gorges, valleys, and ranges, and experiences extreme meteorological phenomena including seasonal cyclonic activity. These features are expected to influence patterns of genetic structuring throughout the landscape either by promoting or restricting the movement of pollen and seed. Whilst a growing body of literature exists for the fauna endemic to this region, less is known about the forces shaping the evolution of plant taxa. In this study we investigate the phylogeography of two iconic Pilbara tree species, the Hamersley Bloodwood (Corymbia hamersleyana) and Western Gidgee (Acacia pruinocarpa), by assessing patterns of variation and structure in several chloroplast DNA regions and nuclear microsatellite loci developed for each species. Gene flow was found to be extensive in both taxa and there was evidence of long-distance seed dispersal across the region (pollen to seed ratios of 6.67 and 2.96 for C. hamersleyana and A. pruinocarpa, respectively), which may result from flooding and strong wind gusts associated with extreme cyclonic activity. Both species possessed high levels of cpDNA genetic diversity in comparison to those from formerly glaciated landscapes (C. hamersleyana = 14 haplotypes, A. pruinocarpa = 37 haplotypes) and showed evidence of deep lineage diversification occurring from the late Miocene, a time of intensifying aridity in this landscape that appears to be a critical driver of evolution in Pilbara taxa. In contrast to another study, we did not find evidence for topographic features acting as refugia for the widely sampled C. hamersleyana.
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Affiliation(s)
- Heidi M. Nistelberger
- Department of Biodiversity, Conservation and Attractions, Biodiversity and Conservation Science, Locked Bag 104, Bentley Delivery Centre, Perth, WA 6983, Australia; (R.M.B.); (S.v.L.); (D.J.C.); (S.L.M.); (B.M.M.); (M.H.); (M.B.)
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Lullfitz A, Byrne M, Knapp L, Hopper SD. Platysace (Apiaceae) of south-western Australia: silent story tellers of an ancient human landscape. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa035] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AbstractHigh gene flow and a population structure corresponding to human rather than geographical drivers are likely to be genetic patterns of human-dispersed plant taxa. We examined variation in geographical structure and gene flow estimates based on three non-coding regions of plastid DNA in three south-west Australian members of the Platysace genus to identify whether a human influence on dispersion of utilized taxa was detectable. Edible tubers of Platysace deflexa and Platysace trachymenioides have been harvested historically by Noongar traditional owners, whereas Platysace effusa has no known cultural significance. We found differences between utilized and non-utilized taxa, particularly when considered against the generally complex phylogeographical patterning in south-west Australian plant taxa. Platysace effusa showed a pattern of high population divergence, low gene flow and multiple refugia, consistent with a long evolutionary history, past climatic oscillations and persistence in a highly fragmented landscape. In contrast, higher gene flow estimates, less divergence between populations and common haplotypes in P. deflexa and in P. trachymenioides over the south-eastern part of its range are consistent with anthropogenic influences. This study contributes to the understanding of human influences on south-west Australian plant taxa that have been present since the late Pleistocene, but to date have received little scientific attention.
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Affiliation(s)
- Alison Lullfitz
- Centre of Excellence in Natural Resource Management, School of Agriculture & Environment, The University of Western Australia, Albany, WA, Australia
| | - Margaret Byrne
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Lynette Knapp
- Centre of Excellence in Natural Resource Management, School of Agriculture & Environment, The University of Western Australia, Albany, WA, Australia
| | - Stephen D Hopper
- Centre of Excellence in Natural Resource Management, School of Agriculture & Environment, The University of Western Australia, Albany, WA, Australia
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Monks L, Barrett S, Beecham B, Byrne M, Chant A, Coates D, Cochrane JA, Crawford A, Dillon R, Yates C. Recovery of threatened plant species and their habitats in the biodiversity hotspot of the Southwest Australian Floristic Region. PLANT DIVERSITY 2019; 41:59-74. [PMID: 31193161 PMCID: PMC6520493 DOI: 10.1016/j.pld.2018.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 09/19/2018] [Accepted: 09/19/2018] [Indexed: 05/22/2023]
Abstract
The Southwest Australian Floristic Region (SWAFR) is a global biodiversity hotspot with high plant diversity and endemism and a broad range of threatening processes. An outcome of this is a high proportion of rare and threatened plant species. Ongoing discovery and taxonomic description of new species, many of which are rare, increases the challenges for recovery of threatened species and prioritisation of conservation actions. Current conservation of this diverse flora is based on integrated and scientific evidence-based management. Here we present an overview of current approaches to the conservation of threatened flora in the SWAFR with a focus on active management through recovery and restoration that is integrated with targeted research. Key threats include disease, fragmentation, invasive weeds, altered fire regimes, grazing, altered hydro-ecology and climate change. We highlight the integrated approach to management of threats and recovery of species with four case studies of threatened flora recovery projects that illustrate the breadth of interventions ranging from In situ management to conservation reintroductions and restoration of threatened species habitats. Our review and case studies emphasise that despite the scale of the challenge, a scientific understanding of threats and their impacts enables effective conservation actions to arrest decline and enhance recovery of threatened species and habitats.
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Affiliation(s)
- Leonie Monks
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
- Corresponding author.
| | - Sarah Barrett
- Parks and Wildlife Service, Department of Biodiversity, Conservation and Attractions. 120 Albany Highway, Albany, Western Australia, 6330, Australia
| | - Brett Beecham
- Parks and Wildlife Service, Department of Biodiversity, Conservation and Attractions. P.O. Box 100, Narrogin, Western Australia, 6312, Australia
| | - Margaret Byrne
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
| | - Alanna Chant
- Parks and Wildlife Service, Department of Biodiversity, Conservation and Attractions. P.O. Box 72, Geraldton, Western Australia, 6531, Australia
| | - David Coates
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
| | - J. Anne Cochrane
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
| | - Andrew Crawford
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
| | - Rebecca Dillon
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
| | - Colin Yates
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia, 6983, Australia
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Coates DJ, Byrne M, Moritz C. Genetic Diversity and Conservation Units: Dealing With the Species-Population Continuum in the Age of Genomics. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00165] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Sampson J, Tapper S, Coates D, Hankinson M, Mcarthur S, Byrne M. Persistence with episodic range expansion from the early Pleistocene: the distribution of genetic variation in the forest tree Corymbia calophylla (Myrtaceae) in south-western Australia. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/blx168] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jane Sampson
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Sarah Tapper
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - David Coates
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Maggie Hankinson
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Shelley Mcarthur
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
| | - Margaret Byrne
- Science and Conservation Division, Department of Biodiversity, Conservation and Attractions, Bentley Delivery Centre, WA, Australia
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Genetic divergence between colonies of Flesh-footed Shearwater Ardenna carneipes exhibiting different foraging strategies. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0994-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Eberle J, Rödder D, Beckett M, Ahrens D. Landscape genetics indicate recently increased habitat fragmentation in African forest-associated chafers. GLOBAL CHANGE BIOLOGY 2017; 23:1988-2004. [PMID: 28063178 DOI: 10.1111/gcb.13616] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/22/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
Today, indigenous forests cover less than 0.6% of South Africa's land surface and are highly fragmented. Most forest relicts are very small and typically occur in fire-protected gorges along the eastern Great Escarpment. Yet, they hold a unique and valuable fauna with high endemism and ancient phylogenetic lineages, fostered by long-term climatic stability and complex microclimates. Despite numerous studies on southern African vegetation cover, the current state of knowledge about the natural extension of indigenous forests is rather fragmentary. We use an integrated approach of population-level phylogeography and climatic niche modeling of forest-associated chafer species to assess connectivity and extent of forest habitats since the last glacial maximum. Current and past species distribution models ascertained potential fluctuations of forest distribution and supported a much wider potential current extension of forests based on climatic data. Considerable genetic admixture of mitochondrial and nuclear DNA among many populations and an increase in mean population mutation rate in Extended Bayesian Skyline Plots of all species indicated more extended or better connected forests in the recent past (<5 kya). Genetic isolation of certain populations, as revealed by population differentiation statistics (GST'), as well as landscape connectivity statistics and habitat succession scenarios suggests considerable loss of habitat connectivity. As major anthropogenic influence is likely, conservational actions need to be considered.
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Affiliation(s)
- Jonas Eberle
- Zoologisches Forschungsmuseum A. Koenig, Centre of Taxonomy and Evolutionary Research, Adenauerallee 160, 53113, Bonn, Germany
| | - Dennis Rödder
- Zoologisches Forschungsmuseum A. Koenig, Centre of Taxonomy and Evolutionary Research, Adenauerallee 160, 53113, Bonn, Germany
| | - Marc Beckett
- Zoologisches Forschungsmuseum A. Koenig, Centre of Taxonomy and Evolutionary Research, Adenauerallee 160, 53113, Bonn, Germany
| | - Dirk Ahrens
- Zoologisches Forschungsmuseum A. Koenig, Centre of Taxonomy and Evolutionary Research, Adenauerallee 160, 53113, Bonn, Germany
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Millar MA, Byrne M, Coates DJ, Roberts JD. Comparative analysis indicates historical persistence and contrasting contemporary structure in sympatric woody perennials of semi-arid south-west Western Australia. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blw005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Dalmaris E, Ramalho CE, Poot P, Veneklaas EJ, Byrne M. A climate change context for the decline of a foundation tree species in south-western Australia: insights from phylogeography and species distribution modelling. ANNALS OF BOTANY 2015; 116:941-52. [PMID: 25851142 PMCID: PMC4640123 DOI: 10.1093/aob/mcv044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/05/2015] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS A worldwide increase in tree decline and mortality has been linked to climate change and, where these represent foundation species, this can have important implications for ecosystem functions. This study tests a combined approach of phylogeographic analysis and species distribution modelling to provide a climate change context for an observed decline in crown health and an increase in mortality in Eucalyptus wandoo, an endemic tree of south-western Australia. METHODS Phylogeographic analyses were undertaken using restriction fragment length polymorphism analysis of chloroplast DNA in 26 populations across the species distribution. Parsimony analysis of haplotype relationships was conducted, a haplotype network was prepared, and haplotype and nucleotide diversity were calculated. Species distribution modelling was undertaken using Maxent models based on extant species occurrences and projected to climate models of the last glacial maximum (LGM). KEY RESULTS A structured pattern of diversity was identified, with the presence of two groups that followed a climatic gradient from mesic to semi-arid regions. Most populations were represented by a single haplotype, but many haplotypes were shared among populations, with some having widespread distributions. A putative refugial area with high haplotype diversity was identified at the centre of the species distribution. Species distribution modelling showed high climatic suitability at the LGM and high climatic stability in the central region where higher genetic diversity was found, and low suitability elsewhere, consistent with a pattern of range contraction. CONCLUSIONS Combination of phylogeography and paleo-distribution modelling can provide an evolutionary context for climate-driven tree decline, as both can be used to cross-validate evidence for refugia and contraction under harsh climatic conditions. This approach identified a central refugial area in the test species E. wandoo, with more recent expansion into peripheral areas from where it had contracted at the LGM. This signature of contraction from lower rainfall areas is consistent with current observations of decline on the semi-arid margin of the range, and indicates low capacity to tolerate forecast climatic change. Identification of a paleo-historical context for current tree decline enables conservation interventions to focus on maintaining genetic diversity, which provides the evolutionary potential for adaptation to climate change.
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Affiliation(s)
- Eleftheria Dalmaris
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia and
| | - Cristina E Ramalho
- Science and Conservation Division, Western Australian Department of Parks and Wildlife, Locked Bag 104, Bentley Delivery Centre, Bentley, 6983 WA, Australia
| | - Pieter Poot
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia and Science and Conservation Division, Western Australian Department of Parks and Wildlife, Locked Bag 104, Bentley Delivery Centre, Bentley, 6983 WA, Australia
| | - Erik J Veneklaas
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia and
| | - Margaret Byrne
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia and Science and Conservation Division, Western Australian Department of Parks and Wildlife, Locked Bag 104, Bentley Delivery Centre, Bentley, 6983 WA, Australia
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Rix MG, Edwards DL, Byrne M, Harvey MS, Joseph L, Roberts JD. Biogeography and speciation of terrestrial fauna in the south-western Australian biodiversity hotspot. Biol Rev Camb Philos Soc 2014; 90:762-93. [PMID: 25125282 DOI: 10.1111/brv.12132] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 06/28/2014] [Accepted: 07/02/2014] [Indexed: 01/21/2023]
Abstract
The south-western land division of Western Australia (SWWA), bordering the temperate Southern and Indian Oceans, is the only global biodiversity hotspot recognised in Australia. Renowned for its extraordinary diversity of endemic plants, and for some of the largest and most botanically significant temperate heathlands and woodlands on Earth, SWWA has long fascinated biogeographers. Its flat, highly weathered topography and the apparent absence of major geographic factors usually implicated in biotic diversification have challenged attempts to explain patterns of biogeography and mechanisms of speciation in the region. Botanical studies have always been central to understanding the biodiversity values of SWWA, although surprisingly few quantitative botanical analyses have allowed for an understanding of historical biogeographic processes in both space and time. Faunistic studies, by contrast, have played little or no role in defining hotspot concepts, despite several decades of accumulating quantitative research on the phylogeny and phylogeography of multiple lineages. In this review we critically analyse datasets with explicit supporting phylogenetic data and estimates of the time since divergence for all available elements of the terrestrial fauna, and compare these datasets to those available for plants. In situ speciation has played more of a role in shaping the south-western Australian fauna than has long been supposed, and has occurred in numerous endemic lineages of freshwater fish, frogs, reptiles, snails and less-vagile arthropods. By contrast, relatively low levels of endemism are found in birds, mammals and highly dispersive insects, and in situ speciation has played a negligible role in generating local endemism in birds and mammals. Quantitative studies provide evidence for at least four mechanisms driving patterns of endemism in south-western Australian animals, including: (i) relictualism of ancient Gondwanan or Pangaean taxa in the High Rainfall Province; (ii) vicariant isolation of lineages west of the Nullarbor divide; (iii) in situ speciation; and (iv) recent population subdivision. From dated quantitative studies we derive four testable models of historical biogeography for animal taxa in SWWA, each explicit in providing a spatial, temporal and topological perspective on patterns of speciation or divergence. For each model we also propose candidate lineages that may be worthy of further study, given what we know of their taxonomy, distributions or relationships. These models formalise four of the strongest patterns seen in many animal taxa from SWWA, although other models are clearly required to explain particular, idiosyncratic patterns. Generating numerous new datasets for suites of co-occurring lineages in SWWA will help refine our understanding of the historical biogeography of the region, highlight gaps in our knowledge, and allow us to derive general postulates from quantitative (rather than qualitative) results. For animals, this process has now begun in earnest, as has the process of taxonomically documenting many of the more diverse invertebrate lineages. The latter remains central to any attempt to appreciate holistically biogeographic patterns and processes in SWWA, and molecular phylogenetic studies should - where possible - also lead to tangible taxonomic outcomes.
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Affiliation(s)
- Michael G Rix
- Australian Centre for Evolutionary Biology and Biodiversity, School of Earth and Environmental Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia
| | - Danielle L Edwards
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, CT 06520, U.S.A
| | - Margaret Byrne
- Science Division, Department of Parks and Wildlife, Locked Bag 104, Bentley DC, Western Australia 6983, Australia
| | - Mark S Harvey
- Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia.,School of Animal Biology, Centre for Evolutionary Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Leo Joseph
- Australian National Wildlife Collection, CSIRO National Facilities and Collections, GPO Box 1700, Canberra, Australian Capital Territory 2601, Australia
| | - J Dale Roberts
- Department of Terrestrial Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia.,School of Animal Biology, Centre for Evolutionary Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.,Centre of Excellence in Natural Resource Management, University of Western Australia, PO Box 5771, Albany, Western Australia 6332, Australia
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