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![The maximum likelihood (ML) phylogram of 26 unique M. nichollsi ND2 haplotypes shows three major lineages with Arenophryne rotunda and Myobatrachus gouldii as outgroups. Clade support is provided by maximum parsimony bootstrap/ML bootstrap/Bayesian posterior probabilities. The TIM+I+G model of DNA evolution was enforced in ML analyses selected by Akaike information criterion tests in modeltest ver. 3.7. A map of the south-western Australian coastline is shown inset with shaded areas representing the distribution of the main range, south coastal and Stirling Ranges lineages. Tissue collection locations [•] for the Metacrinia nichollsi phylogeographic study cover the entire known distribution of the species. Site names and abbreviations are as follows: Naturaliste Ridge Nth (NRN, n = 3); Naturaliste Ridge Mid (NRM, n = 4); Naturaliste Ridge Sth (NRS, n = 4); Sabina (SAB, n = 3); Blackwood Nth (BN, n = 4); Blackwood Sth (BS, n = 4); Donnelly-Warren Nth (DWN, n = 4); Donnelly-Warren Sth (DWS, n = 4); Shannon-Gardner Nth (SGN, n = 2); Shannon-Gardner Sth (SGS, n = 3); Deep-Frankland Nth (DFN, n = 5); Deep-Frankland Sth (DFS, n = 5), Kent-Hay Nth (KHN, n = 3); Kent-Hay Sth (KHS, n = 5); Kalgan Nth (KALN, n = 10); Kalgan Sth (KALS, n = 5).](profile/Danielle-Edwards-10/publication/229447511/figure/fig1/AS:267740325871616@1440845676716/The-maximum-likelihood-ML-phylogram-of-26-unique-M-nichollsi-ND2-haplotypes-shows.png)
The maximum likelihood (ML) phylogram of 26 unique M. nichollsi ND2 haplotypes shows three major lineages with Arenophryne rotunda and Myobatrachus gouldii as outgroups. Clade support is provided by maximum parsimony bootstrap/ML bootstrap/Bayesian posterior probabilities. The TIM+I+G model of DNA evolution was enforced in ML analyses selected by Akaike information criterion tests in modeltest ver. 3.7. A map of the south-western Australian coastline is shown inset with shaded areas representing the distribution of the main range, south coastal and Stirling Ranges lineages. Tissue collection locations [•] for the Metacrinia nichollsi phylogeographic study cover the entire known distribution of the species. Site names and abbreviations are as follows: Naturaliste Ridge Nth (NRN, n = 3); Naturaliste Ridge Mid (NRM, n = 4); Naturaliste Ridge Sth (NRS, n = 4); Sabina (SAB, n = 3); Blackwood Nth (BN, n = 4); Blackwood Sth (BS, n = 4); Donnelly-Warren Nth (DWN, n = 4); Donnelly-Warren Sth (DWS, n = 4); Shannon-Gardner Nth (SGN, n = 2); Shannon-Gardner Sth (SGS, n = 3); Deep-Frankland Nth (DFN, n = 5); Deep-Frankland Sth (DFS, n = 5), Kent-Hay Nth (KHN, n = 3); Kent-Hay Sth (KHS, n = 5); Kalgan Nth (KALN, n = 10); Kalgan Sth (KALS, n = 5).
Source publication
Aim To assess phylogeographic pattern throughout the range of Metacrinia nichollsi in order to develop specific biogeographical hypotheses for the wet forests of south‐western Australia. This was carried out by contrasting a direct‐developing frog species, M. nichollsi , that breeds independently of free surface water with conventional, aquatic bre...
Contexts in source publication
Context 1
... individuals were sampled (toe-clips) from 16 sites across the entire species distribution, with two to five animals sampled per site (Fig. 1). The gap that exists between the Stirling Ranges population and the main range of the species is real: both current and historical surveys have failed to find the species in intervening areas. Past and present surveys in the Porongurup Mountains (34°40¢46¢¢, 117°52¢23¢¢) have recovered no records of the species (B.Y. Main has ...
Context 2
... Base = (0.2825; 0.3564; 0.1272), Nst = 6, Rmat = (1.0000; 23.0322; 0.3433; 0.3433; 5.8514), Rates = gamma, Shape = 0.7316 and Pinvar = 0.6805 were enforced in a likelihood analysis with 100 bootstrap replicates to assess branch support. Parallel Bayesian runs were identical, and major lineages were all well supported. The phylogram presented in Fig. 1 shows three main lineages. The first lineage has a disjunct distribution across some south coastal catchments (SCL), a second is endemic to the Stirling Ranges (SRL), and a third covers the remainder of the species main range (MRL). The SRL had no genetic diversity, despite the fact that samples came from two sites across the range of ...
Context 3
... are two major phylogenetic divergence events within the M. nichollsi lineage that account for the majority of the genetic diversity observed. The first is the separation of the relictual Stirling Ranges populations (SRL) from the populations in the remainder of the species range during the late Miocene-early Pliocene (Figs 1 and 3). The second splits the remainder of the species distribution into a lineage with a disjunct distribution across the south coast (SCL) and another covering the majority of the species range (MRL), with divergence estimates dating this split during the mid-to late Pliocene (Figs 1 and 3). ...
Context 4
... first is the separation of the relictual Stirling Ranges populations (SRL) from the populations in the remainder of the species range during the late Miocene-early Pliocene (Figs 1 and 3). The second splits the remainder of the species distribution into a lineage with a disjunct distribution across the south coast (SCL) and another covering the majority of the species range (MRL), with divergence estimates dating this split during the mid-to late Pliocene (Figs 1 and 3). The biogeographical patterns observed in each of these clades appear to be vastly different. ...
Context 5
... is likely to have contracted towards the coast, where rainfall remained high, albeit reduced, during arid cycles, as indicated by the large number of relictual animals and plants ( Hopper et al., 1996). In the north (MRL), individuals may have persisted in a number of sites, for example Lake Muir or parts of the upper Blackwood catchment (see Fig. 1), which may have remained wet enough during severe arid pulses in the Pliocene. The individual phylogeographic histories of the two lineages, SCL and MRL, give some indication of the possible historic scenarios that might explain the current distribution of these divergent ...
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Citations
... Interestingly, the spatial structuring found in W. carteri is similar to that observed in other taxa including flora and fauna for which intraspecific genetic diversity is not uniformly distributed (Hopper & Gioia, 2004;Davies & Stewart, 2013;Rix et al., 2015). Many species within the region also comprise highly divergent western and southern lineages as a result of contraction to separate mesic refugia during early-mid Pleistocene arid cycling (Edwards, Roberts & Keogh, 2007;Edwards, Roberts & Keogh, 2008;Nistelberger et al., 2014). Within these primary lineages, a secondary pattern of highly localized haplotypes is also common, indicating more recent isolation of populations as a result of increasing aridification (Byrne, 2008;Byrne et al., 2011). ...
Intraspecific genetic diversity provides the evolutionary potential to adapt to changing environments and ‘hotspots’ of high intraspecific diversity are recognized as key targets for conservation.
In south‐western Australia, intraspecific genetic diversity for mesic taxa is not uniformly distributed. Many species comprise highly divergent lineages with unique haplotypes resulting from contraction to refugia during historical arid cycles. Sampling strategies in studies of the region’s unique and ancient freshwater fauna have often focused on broad distributional range, making it difficult to determine boundaries between lineages and the location of genetic hotspots.
This study explored the spatial distribution of intraspecific genetic diversity in the threatened freshwater mussel, Westralunio carteri . Mitochondrial DNA sequences for 164 specimens, sampled from all basins within the distribution of the species, were used to describe lineage boundaries and the location of hotspots, and to reconstruct historical demographics.
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Conservation assessments often focus on the species as a whole, even though sublineages, hotspots and the threats faced are not evenly distributed across the species range. This paper highlights that effective conservation of spatially structured taxa requires targeted management of multiple genetic units. Given the importance of formal taxonomic description for conservation listings, further investigation of the potential for species delimitation within W. carteri is required.
... Genetic structure has been identified in the native range of P. lophantha as part of studies focusing on the population structure outside Australia [37] and adaptive responses to novel ranges [38]. Phylogeographic patterns within Australia have not been explored in detail in P. lophantha, but phylogeographic structure identified in SW WA in both plants (e.g., [5,[54][55][56]) and animals (e.g., [57][58][59][60][61]) has contributed to conservation in the region by enabling genetically informed management. ...
... The southwest coast genetic cluster containing populations BH and PO is located close to where the BFP and Southeast Coastal Province (SCP) meet [27]. This area was hypothesized to be a refugium in the Pliocene and Pleistocene [58,107], but there is no evidence of this in P. lophantha. However, in another proposed refugial area sitting on the oldest geology in SW WA [58], populations DR, MA, and GR form a cluster in DAPC and contribute to the genetic admixture of populations YG, BD, and RC. ...
... This area was hypothesized to be a refugium in the Pliocene and Pleistocene [58,107], but there is no evidence of this in P. lophantha. However, in another proposed refugial area sitting on the oldest geology in SW WA [58], populations DR, MA, and GR form a cluster in DAPC and contribute to the genetic admixture of populations YG, BD, and RC. ...
Paraseriantheslophantha subsp. lophantha (Leguminosae) is native to southwestern Australia, but has become naturalized in eastern Australia and in countries around the world. Previous studies have investigated the introduction sources for P. lophantha subsp. lophantha overseas, but here, we expand on the knowledge of genetic patterns in its native and naturalized range in Australia. Genetic patterns were examined using nine nuclear microsatellite loci and three chloroplast DNA markers. The native populations exhibited phylogeographic patterns, including north-south differentiation, and a genetic signal related to temperature gradients. Naturalized Australian populations displayed lower overall genetic variation and no phylogeographic patterns. Several naturalized populations separated by large distances (350–650 km) shared multi-locus genotypes, supporting the notion of a shared source of germplasm and possible inbreeding due to human-mediated introductions from a limited number of individuals and/or source populations within the native range. We advocate that management strategies are tailored to the distinct conservation aims underpinning conservation in native or naturalized populations. Within the native distribution, management should have a long-term aim to replicate historical evolutionary processes, whereas in naturalized populations, immediate actions may be required to reduce the abundance of P. lophantha subsp. lophantha and minimize its invasive impact on the recipient vegetation.
... In the same broad region as G. leai, Crinia georgiana and Metacrinia nichollsi have marked, genetic subdivisions (Edwards et al., , 2008, and the range of Heleioporus inornatus is split into west coast and southeast coast occurrences with no obvious landscape feature separating these sets of populations (Lee, 1967). Intraspecific variation of frog lineages in southwestern Australia may reflect the impact of broad drying and cooling trends since the Miocene Rix et al., 2015), recent climate variations, or complex but subtle physiographic properties of the landscapes (Pain et al., 2011). ...
My research on anurans has been diverse: biogeography, speciation, acoustics, polyandry, sperm competition, and conservation. My interests in biology started in natural history but, in the late 1960s as an undergraduate student, I was receptive to emerging new ideas in biogeography and evolutionary biology: continental drift and neutral theory. My focus in this “Perspective” is an explanation of how diversity has evolved in the frog fauna of southwestern Australia, where I have worked since 1978. I discuss the roles of range fragmentation, genetic drift, directional sexual selection, polyploidy, and simultaneous polyandry as processes driving the evolution of diversity in the sometimes-bizarre frog fauna of southwestern Australia. I identify features that can characterize polyandrous anurans: e.g., large testes, sperm morphology, and, possibly, complex calls with an example of the latter in Geocrinia leai. I discuss how current anuran life histories vary across rainfall and temperature gradients and how derivation of more-arid adapted forms is a well-defined historic biogeographic pattern in southwestern Australia. My observations over time leave me cautiously optimistic about the prospects for frogs affected by global warming.
... A seed collection programme for ex situ storage and conservation of both populations would provide insurance against the event of sudden declines that would critically threaten the persistence of B. biterax in this region. This will be important given the presence of unique chloroplast haplotypes and very strong SNP differentiation of Stirling Range populations and given that the Stirling Range is known to be a centre of wider floral (Crisp et al., 2001;Hopper & Gioia, 2004;Barrett & Yates, 2015) and faunal (Edwards et al., 2008;Edward & Harvey, 2010;Cooper et al., 2011;Kay & Keogh, 2012;Rix & Harvey, 2012) endemism and diversity. ...
Dramatic range disjunction of plant populations can have significant genetic consequences that directly influence conservation planning. Genomic technologies provide improved opportunity to investigate genetic variation in species of conservation concern, where small sample sizes often limited the use of previous technologies. In this study, we used 1134 neutral single nucleotide polymorphisms to investigate genomic diversity, differentiation and ancestry across the highly disjunct range of Banksia biterax to identify conservation units and make management recommendations. We also sequenced four non-coding regions of the chloroplast genome to infer phylogeographical history. We found strong genetic differentiation associated with disjunct populations at several geographical scales, but levels of diversity were more influenced by effective population size. Divergent haplotypes and a lack of haplotype sharing indicated that disjunct populations have been historically isolated from the core range of the species. Our data indicate that disjunction can drive strong differentiation but does not necessarily reduce diversity and that disjunct populations of B. biterax represent long-term relicts in the landscape. Three geographical regions should each be considered independent evolutionarily significant units, two of which are of conservation concern. Fire management, pathogen control and ex situ seed storage are key management actions for the long-term persistence of B. biterax.
... Allopatric speciation has been noted throughout southwest Western Australia for a range of taxonomic groups with limited dispersal capabilities, including many invertebrate groups (e.g. spiders, isopods and crayfishes) and some frog species [29,85,86]. ...
Pygmy perches (Percichthyidae) are a group of poorly dispersing freshwater fishes that have a puzzling biogeographic disjunction across southern Australia. Current understanding of pygmy perch phylogenetic relationships suggests past east–west migrations across a vast expanse of now arid habitat in central southern Australia, a region lacking contemporary rivers. Pygmy perches also represent a threatened group with confusing taxonomy and potentially cryptic species diversity. Here, we present the first study of the evolutionary history of pygmy perches based on genome-wide information. Data from 13 991 ddRAD loci and a concatenated sequence of 1 075 734 bp were generated for all currently described and potentially cryptic species. Phylogenetic relationships, biogeographic history and cryptic diversification were inferred using a framework that combines phylogenomics, species delimitation and estimation of divergence times. The genome-wide phylogeny clarified the biogeographic history of pygmy perches, demonstrating multiple east–west events of divergence within the group across the Australian continent. These results also resolved discordance between nuclear and mitochondrial data from a previous study. In addition, we propose three cryptic species within a southwestern species complex. The finding of potentially new species demonstrates that pygmy perches may be even more susceptible to ecological and demographic threats than previously thought. Our results have substantial implications for improving conservation legislation of pygmy perch lineages, especially in southwestern Western Australia.
... However, we are unable to test this hypothesis from the data available. 479 The remaining lineages cannot be delineated in the same way: genetic divergences in 508 ITS2 are much lower (ITS2 < 6.7%;) and the tree topology less resolved (Appendix 509 5b), isolation was not as long (Table 1) diversity is a prime feature of Geocrinia species (Driscoll, 1998a,b), other 571 myobatrachid frogs (Edwards et al., 2007;Edwards et al., 2008), and P. giganteus. 572 ...
... Suitable habitat decreases according to the colour 962 gradient from dark (highest environmental suitability) to pale blue (lower suitability) 963 and white (environment not suitable). Emission scenarios: A1B = future world more 964 integrated, and A2A = future world more divided with emphasis on Distribution maps of selected animal lineages in the Warren bioregion: A = 968 frogs of the Geocrinia complex (Wardell-Johnson and Roberts, 1996; Driscoll, 1998); 969 B = aquatic crayfish (Horwitz and Adams, 2000); C = the frog species Metacrinia 970nichollsi(Edwards et al., 2008); and D = onychophorans(Reid, 2002). Note that the vertebrate studies are based on DNA sequence/allozyme data whilst ...
Southwestern Australia is one of the global biodiversity hotspots. Like many other hotspots, comparatively few data are available explaining speciation patterns in endemic animal lineages, which hampers conservation efforts and a deeper understanding of how diversity is generated and maintained. I investigated the phylogeographic structure of an ancient arachnid species, the pseudoscorpion Pseudotyrannochthonius giganteus, endemic to the mesic eucalypt forests of southwestern Australia. This species is habitat restricted and has morphologically divergent populations in epigean (forest) and hypogean (karst) habitats. Phylogenetic, molecular clock and population genetic analyses of mitochondrial (COI mtDNA) and nuclear (ITS2 rDNA) data revealed a complex population structure, with six allopatric lineages separated by vicariant barriers, such as rivers. These lineages diverged between the late Miocene and Pliocene epochs, characterised by increasing climatic cycles between mesic/warm and arid/cold. Surprisingly, specimens from caves were genetically similar to those from forests, indicating subterranean isolation has not driven diversification. Instead, genetic diversity is clustered in a small area, coinciding with highest rainfall and lowest seasonality in Western Australia. Future climates, warmer and drier than today, will lead to range retraction towards this area and mimic past variations that have shaped contemporary diversity. Southwestern Australia is an ancient, stable landscape that allowed for persistence of ancient lineages, such as P. giganteus. Historic climatic fluctuations have driven diversification, generating highly structured systems and localised centres of endemism. Other ancient landscapes, e.g. South Africa’s Cape Provinces, are expected to share similarly complex patterns of invertebrate biodiversity. Unravelling these is essential to informed conservation decisions.
... The reliance of Onychophora on moist habitats has possibly confined them to the high-rainfall area along the coast of south-western Australia and also to the upland areas such as the Stirling and Porongurups Ranges. This substantiates the hypotheses supported by the biogeographic distributions of other fauna such as Bertmainius mygalomorph spiders (Cooper et al. 2011;Harvey et al. 2015;Rix et al. 2017), assassin spiders (Rix and Harvey 2012), millipedes (Moir et al. 2009) and frogs (Edwards et al. , 2008; see Rix et al. (2015) for further discussion. ...
... This study supports the growing body of evidence that suggests that the climatic history of Australia, paired with the topographical conditions of south-western Australia, have caused an explosion of speciation in the region (e.g . Hopper 1979;Hopper and Gioia 2004;Edwards et al. , 2008Moir et al. 2009;Cooper et al. 2011), arguing for increased protection of forests in the area, especially those in upland regions (e.g. Porongurups, Stirling Range). ...
There is a yet uncovered multitude of species to be found among Western Australian Onychophora. Kumbadjena, one of the two genera that reside in this region, has been previously suggested to house an extensive species complex. Morphology alone has not been able to elucidate the diversity in this genus and has instead muddled species delineations. Topologies and species delimitation analyses resulting from the sequences of two mitochondrial ribosomal markers (12S rRNA and 16S rRNA), one nuclear ribosomal marker (18S rRNA), and one mitochondrial protein-coding gene (cytochrome c oxidase subunit I) are indicative of several undescribed species. Fixed diagnostic nucleotide changes in the highly conserved sequences of 18S rRNA warrant distinction of three new species of Kumbadjena: K. toolbrunupensis, sp. nov., K. karricola, sp. nov., and K. extrema, sp. nov. The geographic distributions of the proposed species suggest that Kumbadjena is another example of short-range endemism, a common occurrence in the flora and fauna of the region. The extensive biodiversity and endemism in the region necessitates conservation to preserve the species and processes that promote speciation harboured by Western Australia.
... We also quantified morphology for a much larger group of animals (see below and S1 Fig for the distribution of morphotyped individuals). Metacrinia nicholsii, Arenophryne rotunda and A. xiphorhyncha were included due to their close relationship with M. gouldii and as a comparison of intra-specific genetic distances [36,37]. ...
... We generated sequence data for five loci, including a 1200 base pair region of the mtDNA gene ND2 and associated tRNAs to facilitate comparison with detailed population and species level studies in the sister taxa Metacrinia nicholsii and Arenophryne species [17,37]. ND2 has been used extensively in similar studies on other frogs, e.g. ...
... Glacial arid cycles of the Plio-Pleistocene have been pivotal to generating species diversity in SWA, with many studies identifying these climatic fluctuations as major drivers of inter and intra-specific variation in flora and fauna [5,13,16,37,38]. At the same time, glacial cycles also are thought to have extinguished diversity in a number of taxa occupying regions that experienced particularly hostile arid conditions, enhanced by low-lying homogeneous topography and increased distance from the coast [50]. ...
Southwest Australia (SWA) is a global biodiversity hotspot and a centre of diversity and endemism for the Australo-Papuan myobatrachid frogs. Myobatrachus gouldii (the turtle frog) has a highly derived morphology associated with its forward burrowing behaviour, largely subterranean habit, and unusual mode of reproduction. Its sister genera Metacrinia and Arenophryne have restricted distributions in Western Australia with significant phylogeographic structure, leading to the recent description of a new species in the latter. In contrast, Myobatrachus is distributed widely throughout SWA over multiple climatic zones, but little is known of its population structure, geographic variation in morphology, or reproduction. We generated molecular and morphological data to test for genetic and morphological variation, and to assess whether substrate specialisation in this species may have led to phylogeographic structuring similar to that of other plant and animal taxa in SWA. We assembled sequence data for one mitochondrial and four nuclear DNA loci (3628 base pairs) for 42 turtle frogs sampled throughout their range. Likelihood phylogenetic analyses revealed shallow phylogeographic structure in the mtDNA locus (up to 3.3% genetic distance) and little variation in three of the four nDNA loci. The mtDNA haplotype network suggests five geographically allopatric groups, with no shared haplotypes between regions. These geographic patterns are congruent with several other SWA species, with genetic groups restricted to major hydrological divisions, the Swan Coastal Plain, and the Darling Scarp. The geographically structured genetic groups showed no evidence of significant morphological differentiation (242 individuals), and there was little sexual size dimorphism, but subtle differences in reproductive traits suggest more opportunistic breeding in lower rainfall zones. Call data were compared to sister genera Metacrinia and Arenophryne and found to be highly conservative across the three genera. Like many taxa in SWA, topographic variation and Plio-Pleistocene arid fluctuations likely were historic drivers of diversification in M. gouldii.
... Within the SMB, major climatic gradients and physical features across the landscape are thought to have been important in shaping phylogeographic patterns (Kay and Keogh 2012). For example, strong rainfall and temperature gradients between the High Rainfall Zone of the southwest coast and the inland Transitional Rainfall Zone (Hopper 1979) appear to have been significant barriers to frogs (Wardell-Johnson and Roberts 1993;Edwards et al. 2007Edwards et al. , 2008 and skinks (Kay and Keogh 2012). In addition, physical barriers such as the Darling Scarp (Kay and Keogh 2012) and the waterlogged Pingerup Plains (Wardell-Johnson and Roberts 1993;Edwards et al. 2008) as well as sea-level fluctuations in coastal areas (Edwards et al. 2008;Kay and Keogh 2012) also appear to have been important in the regional diversification of herpetofauna in the SMB. ...
... For example, strong rainfall and temperature gradients between the High Rainfall Zone of the southwest coast and the inland Transitional Rainfall Zone (Hopper 1979) appear to have been significant barriers to frogs (Wardell-Johnson and Roberts 1993;Edwards et al. 2007Edwards et al. , 2008 and skinks (Kay and Keogh 2012). In addition, physical barriers such as the Darling Scarp (Kay and Keogh 2012) and the waterlogged Pingerup Plains (Wardell-Johnson and Roberts 1993;Edwards et al. 2008) as well as sea-level fluctuations in coastal areas (Edwards et al. 2008;Kay and Keogh 2012) also appear to have been important in the regional diversification of herpetofauna in the SMB. ...
... For example, strong rainfall and temperature gradients between the High Rainfall Zone of the southwest coast and the inland Transitional Rainfall Zone (Hopper 1979) appear to have been significant barriers to frogs (Wardell-Johnson and Roberts 1993;Edwards et al. 2007Edwards et al. , 2008 and skinks (Kay and Keogh 2012). In addition, physical barriers such as the Darling Scarp (Kay and Keogh 2012) and the waterlogged Pingerup Plains (Wardell-Johnson and Roberts 1993;Edwards et al. 2008) as well as sea-level fluctuations in coastal areas (Edwards et al. 2008;Kay and Keogh 2012) also appear to have been important in the regional diversification of herpetofauna in the SMB. ...
... However, the location of the south-eastern nuclear genetic cluster in K. coccinea was notable, given its apparent demarcation by the Blackwood River system, south of which the broad geomorphological zone of the region also changes (Schoknecht et al., 2004). The Blackwood River has been identified as a boundary between lineages within two small animal species (Gouws et al., 2006;Edwards et al., 2008), although chloroplast lineage structure in jarrah did not follow the same pattern (Wheeler & Byrne, 2006). The river may therefore act as a stronger barrier to gene flow for understorey species and small animals than it does for large, dominant forest trees. ...
Aim
Terrestrial plant ecology and evolution is significantly influenced by the phenomenon of fire, but studies of its potential impact on intraspecific genetic variation and phylogeography are rare. This understanding will be important for predicting the biogeographical consequences of changing fire regimes under global climate change. Here, we asked whether changing historical fire regimes, together with climatic and geological history, have influenced phylogeographical patterns in a fire‐ephemeral vine. We also asked whether demographic stochasticity associated with a fire‐ephemeral life history results in nuclear genetic drift as expected from spatio‐temporal patchiness, or if this effect is buffered by the connectivity and diversity afforded by a persistent soil seed bank.
Location
The fire‐prone, mediterranean‐type climate region of south‐western Australia.
Methods
We used Bayesian phylogeny reconstruction and statistical tests of demographic expansion based on variation at three non‐coding chloroplast sequence regions ( atpF, ndhF–rpl32, psbD–trnT ) to reconstruct phylogeographical history. Nuclear diversity and population structure at 11 microsatellite loci were investigated for evidence of genetic drift.
Results
Evidence for prolonged persistence and a lack of vicariance within the species range was found, together with strong evidence of historical demographic expansion. Contrary to expectations, there was little evidence of nuclear genetic drift despite strong, above‐ground spatio‐temporal population patchiness.
Main conclusions
Our findings suggest that a late Pleistocene increase in fire frequency may have led to demographic expansion in this fire‐ephemeral species; alternatively, the expansion signal may be an inherent feature of fire ephemerals with a persistent soil seed bank. Prolonged climatic stability has likely fostered persistence within the species range in contrast to contraction and vicariance. The notable lack of genetic drift implies a role for ample pollen dispersal and a long‐lived soil seed bank in the maintenance of diversity and connectivity in an otherwise stochastic, fire‐driven system.
