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• Significant variation among the GWAS panel was recorded for all the traits • 143 MTAs associations were observed for all traits distributed on all chromosomes • Eleven stable QTLs were identified for number of seeds per plant and pods per plant • MLD was utilised to establish correlation between phenotypic traits to loci's Genome wide association study (GWAS) was performed to identify loci associated with three agronomic traits namely seeds per pod, pods per plant and number of seeds per plant of horsegram (Macrotyloma uniflorum). Total 87 accesions of horsegram from different geographical regions of India and one wild relative from Australia were utilised for the genome wide association studies. The genotyping was carried out using genotype-by-sequencing technology and after high quality filtering, minor allele frequency of 0.05, a total of 55,656 quality SNPs were utilised for determining Marker-Trait Association. The LD decay varied across the chromosomes form 8 kb to 300 kb. Further, the population structure analysis has clustered the accession into three subpopulations. All the 88 accessions of horsegram were evaluated at Palampur (32.1109° N, 76.5363° E) and Bajaura (31.8465°N, 77.1605°E) locations of North-Western Himalayan region, India from. In the current study, 143 MTAs associations were observed for seeds per pod distributed on all 8 chromosomes, 2 for pods per plant at chromosomes 2 and 3 and 1 for number of seeds per plant at chromosome 7. However, total 11 stable QTLs (9 for number of seeds per plant and 2 for pods per plant) were also identified. These QTLs can serve as a potential source for marker assisted selection. The genes identified within and in proximity to the stable QTLs will serve as a bridge between genetic information and its practical application for crop improvement. [ABSTRACT FROM AUTHOR]

Habitat fragmentation can increase the chance of population bottlenecks and inbreeding, and may ultimately lead to reduced fitness and local extinction. Notelaea lloydii is a native olive species endemic to Australia and listed as vulnerable due to its restricted distribution. A recent molecular systematics study has revealed there might be some geographic structuring among N. lloydii populations. Therefore, we undertook a genome‐wide single nucleotide polymorphism (SNP) analysis to determine levels and patterns of genetic diversity, inbreeding and gene flow within and among N. lloydii populations in south‐eastern Queensland. Furthermore, as the reproductive phase of a plant's life history has a profound influence on genetic diversity, life history reproductive traits were also studied. Our SNP analysis revealed low genetic diversity, inbreeding and significant genetic structuring even among proximate populations. Results of a flower and fruit bagging experiment in two consecutive seasons revealed that N. lloydii produced many flowers but only a few fruits survived to maturity. There were no differences in bagged and un‐bagged flowering and fruiting rates, and therefore, we conclude that the high fruit abortion rate was probably due to inbreeding depression and/or suboptimal conditions, rather than pollinator availability and insect attack. Overall, results of this study indicate that the populations of N. lloydii are small, inbred and genetically isolated and represent unique management units that require local conservation management due to ongoing threats associated with urbanisation. [ABSTRACT FROM AUTHOR]

Anthropogenic impacts are typically detrimental to tropical coral reefs, but the effect of increasing environmental stress and variability on the size structure of coral communities remains poorly understood. This limits our ability to effectively conserve coral reef ecosystems because size specific dynamics are rarely incorporated. Our aim is to quantify variation in the size structure of coral populations across 20 sites along a tropical‐to‐subtropical environmental gradient on the east coast of Australia (~ 23 to 30°S), to determine how size structure changes with a gradient of sea surface temperature, turbidity, productivity and light levels. We use two approaches: 1) linear regression with summary statistics (such as median size) as response variables, a method frequently favoured by ecologists and 2) compositional functional regression, a novel method using entire size–frequency distributions as response variables. We then predict coral population size structure with increasing environmental stress and variability. Together, we find fewer but larger coral colonies in marginal reefs, where conditions are typically more variable and stressful, than in tropical reefs. Our model predicts that coral populations may become gradually dominated by larger colonies (> 148 cm2) with increasing environmental stress. Fewer but bigger corals suggest low survival of smaller corals, slow growth, and/or poor recruitment. This finding is concerning for the future of coral reefs, as it implies that current marginal populations, or future reefs in increasingly stressful environmental conditions may have low recovery potential. We highlight the importance of continuously monitoring changes to population structure over biogeographic scales. [ABSTRACT FROM AUTHOR]

Admixture between species is a cause for concern in wildlife management. Canids are particularly vulnerable to interspecific hybridisation, and genetic admixture has shaped their evolutionary history. Microsatellite DNA testing, relying on a small number of genetic markers and geographically restricted reference populations, has identified extensive domestic dog admixture in Australian dingoes and driven conservation management policy. But there exists a concern that geographic variation in dingo genotypes could confound ancestry analyses that use a small number of genetic markers. Here, we apply genome‐wide single‐nucleotide polymorphism (SNP) genotyping to a set of 402 wild and captive dingoes collected from across Australia and then carry out comparisons to domestic dogs. We then perform ancestry modelling and biogeographic analyses to characterise population structure in dingoes and investigate the extent of admixture between dingoes and dogs in different regions of the continent. We show that there are at least five distinct dingo populations across Australia. We observed limited evidence of dog admixture in wild dingoes. Our work challenges previous reports regarding the occurrence and extent of dog admixture in dingoes, as our ancestry analyses show that previous assessments severely overestimate the degree of domestic dog admixture in dingo populations, particularly in south‐eastern Australia. These findings strongly support the use of genome‐wide SNP genotyping as a refined method for wildlife managers and policymakers to assess and inform dingo management policy and legislation moving forwards. [ABSTRACT FROM AUTHOR]

Biogeographic barriers can restrict gene flow, but variation in ecological drivers of dispersal influences the effectiveness of these barriers among different species. Detailed information about the genetic connectivity and movement of waterfowl across biogeographic barriers in northern Australia and Papua New Guinea is limited. We compared genetic connectivity for four species of Australasian waterfowl that vary in their capacity and predisposition for dispersal: Radjah Shelduck (Radjah radjah), Wandering Whistling Duck (Dendrocygna arcuata), Green Pygmy Goose (Nettapus pulchellus), and Pacific Black Duck (Anas superciliosa). We obtained >3,700 loci from double-digest restriction-associated DNA sequencing for 15 to 40 individuals per species and found idiosyncratic patterns of population structure among the four species. The mostly sedentary Radjah Shelduck exhibited clear genetic differences between New Guinea and Australia as well as among locations within Australia. Although the population structure was consistent with isolation by distance, the Torres Strait and Carpentaria Barrier contributed more to genetic differences than geographic distance alone. In contrast, the presumed sedentary Green Pygmy Goose did not show obvious structure. Likewise, populations of the more dispersive Wandering Whistling Duck and Pacific Black Duck were unstructured and genetically indistinguishable between southern New Guinea and northern Australia. Our data suggest that some Australo-Papuan biogeographical barriers are insufficient to impede gene flow in waterfowl species capable of dispersing great distances. In sedentary species like the Radjah Shelduck, these barriers, perhaps coupled with its ecology and natural history, restrict gene flow. Our findings bring new insight into the population ecology of Australo-Papuan waterfowl. [ABSTRACT FROM AUTHOR]

Narrowly endemic species are particularly vulnerable to catastrophic events. Compared to widespread species, they may also be less capable of adapting to shifts in environmental pressures as a result of specialisation on a narrow range of local condition and limited ability to disperse. However, life-history traits, such as preferential outcrossing and high fecundity can maintain genetic diversity and evolutionary potential, and boost species resilience. The endangered Grevillea bedggoodiana (Enfield Grevillea) is an understorey shrub restricted to an area of ca. 150 km2 in south-eastern Australia with a legacy of large-scale anthropogenic disturbance. Prior to this study little was known about its biology and population structure. Here, its breeding system was assessed through a controlled pollination experiment at one of its central populations, and eight populations were sampled for genetic analysis with microsatellite markers. The species was found to be preferentially outcrossing, with no evidence of pollination limitation. In most populations, allelic richness, observed heterozygosity and gene diversity were high (Ar: 3.8–6.3; Ho: 0.45–0.65, He: 0.60 − 0.75). However, the inbreeding coefficients were significant in at least four populations, ranging from Fi -0.061 to 0.259 despite high outcrossing rates. Estimated reproductive rates varied among sampled populations but were independent of gene diversity and inbreeding. Despite its small geographic range, the species' populations showed moderate differentiation (AMOVA: FST = 0.123), which was largely attributable to isolation by distance. We interpret these results as suggesting that G. bedggoodiana is reproductively healthy and has maintained high levels of genetic diversity despite recent disturbance. [ABSTRACT FROM AUTHOR]

Fish otoliths encode information on surrounding environmental conditions. This study used otolith chemistry to investigate population structure and potential connectivity in stout whiting (Sillago robusta) along the east coast of Australia. Otoliths were analysed for both minor and trace elements, targeting the otolith core (location of birth) and otolith edge (location of capture), along with Ba:Ca transects to investigate life histories. Significant differences were found between core and edge signatures as well as among sample zones for select trace and minor elements. Otolith edge signatures showed evidence of some heterogeneity among zones, likely influenced by both environmental and physiological factors. This combination of factors is reflected in poor separation of sample zones from the multielement analysis, suggesting that future research may benefit from incorporating additional natural markers. Transects reflected some degree of individuality in Ba:Ca profiles, with evidence for potential exposure to upwelling events, or movement from shallow, inshore habitats into deeper waters. The variation in Ba:Ca profiles among fish suggests that populations are comprised of both resident and migratory individuals. While analysis of otolith chemistry could not reliably separate capture locations, patterns in the data suggest that inshore juvenile habitats are likely to be important in supporting exploited populations. [ABSTRACT FROM AUTHOR]

Mammal declines across northern Australia are one of the major biodiversity loss events occurring globally. There has been no regional assessment of the implications of these species declines for genomic diversity. To address this, we conducted a species‐wide assessment of genomic diversity in the northern quoll (Dasyurus hallucatus), an Endangered marsupial carnivore. We used next generation sequencing methods to genotype 10,191 single nucleotide polymorphisms (SNPs) in 352 individuals from across a 3220‐km length of the continent, investigating patterns of population genomic structure and diversity, and identifying loci showing signals of putative selection. We found strong heterogeneity in the distribution of genomic diversity across the continent, characterized by (i) biogeographical barriers driving hierarchical population structure through long‐term isolation, and (ii) severe reductions in diversity resulting from population declines, exacerbated by the spread of introduced toxic cane toads (Rhinella marina). These results warn of a large ongoing loss of genomic diversity and associated adaptive capacity as mammals decline across northern Australia. Encouragingly, populations of the northern quoll established on toad‐free islands by translocations appear to have maintained most of the initial genomic diversity after 16 years. By mapping patterns of genomic diversity within and among populations, and investigating these patterns in the context of population declines, we can provide conservation managers with data critical to informed decision‐making. This includes the identification of populations that are candidates for genetic management, the importance of remnant island and insurance/translocated populations for the conservation of genetic diversity, and the characterization of putative evolutionarily significant units. [ABSTRACT FROM AUTHOR]

Genome-wide, single nucleotide polymorphism (SNP) typing can improve the management of valuable marine species by delineating finer scale population structure compared with traditional markers. This approach was applied to the spiny lobster, Panulirus ornatus distributed in the Indo-West Pacific and is one of the most highly valuable seafood products in the world. A total of 3008 SNPs was generated from DArTseq sequencing of 224 lobsters sampled at 13 locations across the Indo-Pacific. SNPs revealed a highly significant genetic structure among samples (analysis of molecular variance FST = 0.046). Pairwise genetic comparison showed significant differences among the majority of sampling locations. Outlier loci (including an outlier SNP mapped to the CASc gene with different allele frequencies among sampling locations) revealed highly significant pairwise differentiation, especially a genetic break between regional populations in northern Australia and South East Asia. Significant pairwise differences in outliers among sampling locations, even over small geographic scales, suggest a possible role of local adaptation on the population structure. Genetic differences identified among samples from northern Australia and South East Asia are sufficient to refute the single-stock hypothesis proposed using conventional genetic markers. The results of genome-level SNPs identify five management units across the species' range, with significant implications for the future fisheries management and aquaculture development of this species. [ABSTRACT FROM AUTHOR]

Fire-killed serotinous trees are often dominant species in fire-prone regions with contrasting wet and dry seasons. We studied a serotinous fire-killed conifer (Callitris preissii, Cupressaceae) to identify the influence of fire regime and climate on geographic variation in level of serotiny, recruitment and population structure. We measured population size distributions, seedling recruitment and level of serotiny for sample stands across a climatic gradient from mesic coastal (including two islands) to semi-arid inland sites in SW Australia. Trees on islands were mostly non-serotinous and were only weakly serotinous on the adjacent mainland in the higher rainfall West coast region. In the semi-arid Goldfields and South inland, and the higher rainfall South coast region, trees were more strongly serotinous with up to six cohorts of closed cones retained on trees. Level of serotiny was stronger at the drier end of the climatic gradient where severe to extreme fire danger weather occurs most frequently, and where vegetation type (e.g., shrublands) supports frequent crown-type, stand-replacing fires. Recruitment was most abundant post-fire in all regions, but seedlings also established inter-fire where there was regular seed fall due to low level of serotiny or spontaneous release of seeds from old cones on trees with a high cone load. Population structures for mainland stands shifted from approximately reverse-J (indicating continuous recruitment) in mesic regions to mainly unimodal (establishment mostly after fire) in drier, inland regions, although some long-unburned inland stands showed occasional inter-fire recruitment, likely linked to high rainfall years. Unimodal population structures characterized islands, where previous studies have identified herbivory on seedlings by refugial populations of native macropods as a limiting factor on inter-fire establishment. Understanding landscape context, response to disturbance, biotic interactions and reproductive traits of dominant species is essential in conservation planning in a rapidly changing global environment. [ABSTRACT FROM AUTHOR]

Emerging plant pathogens have been increasing exponentially over the last century. To address this issue, it is critical to determine whether these pathogens are native to ecosystems or have been recently introduced. Understanding the ecological and evolutionary processes fostering emergence can help to manage their spread and predict epidemics/epiphytotics. Using restriction site‐associated DNA sequencing data, we studied genetic relationships, pathways of spread and the evolutionary history of Phellinus noxius, an emerging root‐rotting fungus of unknown origin, in eastern Asia, Australia and the Pacific Islands. We analysed patterns of genetic variation using Bayesian inference, maximum‐likelihood phylogeny, population splits and mixtures measuring correlations in allele frequencies and genetic drift, and finally applied coalescent‐based theory using Approximate Bayesian computation (ABC) with supervised machine learning. Population structure analyses revealed five genetic groups with signatures of complex recent and ancient migration histories. The most probable scenario of ancient pathogen spread is movement from an unsampled population to Malaysia and the Pacific Islands, with subsequent spread to Taiwan and Australia. Furthermore, ABC analyses indicate P. noxius spread occurred thousands of generations ago, contradicting previous assumptions that this pathogen was recently introduced to multiple geographical regions. Our results suggest that recent emergence of P. noxius in eastern Asia, Australia and the Pacific Islands has probably been driven by anthropogenic and natural disturbances, such as deforestation, land‐use change, severe weather events and/or introduction of exotic plants. This study provides a novel example of applying genome‐wide allele frequency data to unravel the dynamics of pathogen emergence under changing ecosystem conditions. [ABSTRACT FROM AUTHOR]

Macadamia nuts are known globally for their high quality and economic value. Global macadamia commercial nut production amounts to 60,000 metric tonnes and is increasing steadily. South Africa is the leading producer with 29% of worldwide kernel production. Commercial macadamia germplasm was originally selected from a small genepool (mainly Macadamia integrifolia species) from a limited geographic distribution in Australia. These accessions were subsequently bred, cloned and exported across the world to start local macadamia industries. The South African macadamia industry was established with pre-commercial and commercial macadamia from different parts of the world, and local selections were also performed. Many of these accessions have unique genetic compositions that have not been characterized yet. We used 13 nuclear microsatellite markers to study the genetic diversity and structure of macadamia germplasm cultivated in South Africa. We compared four groups of accessions including 31 originating from the Hawaiian Agricultural Experimental Station (HAES), 19 from Australia (AUS), two from California and one from Israel (OTH), 31 from South Africa's locally selected accessions (SA) and 26 from two local Farmers (FARM). We used STRUCTURE, PCoA and neighbour-joining phylogenetic analyses to show that the South African selected accessions include diverse hybrid genotypes with strong Macadamia tetraphylla composition, unlike the Hawaiian commercially released and Australian representative collections that mostly have M. integrifolia or hybrid composition. Our results suggest that the South African selections represent a unique and diverse set of germplasm for future macadamia improvement efforts that will benefit from genomic breeding technologies. [ABSTRACT FROM AUTHOR]

The European rabbit (Oryctolagus cuniculus) is one of the most devastating invasive species in Australia. Since the 1950s, myxoma virus (MYXV) and rabbit haemorrhagic disease virus (RHDV) have been used to manage overabundant rabbit populations. Resistance to MYXV was observed within a few years of the release. More recently, resistance to lethal RHDV infection has also been reported, undermining the efficiency of landscape‐scale rabbit control. Previous studies suggest that genetic resistance to lethal RHDV infection may differ locally between populations, yet the mechanisms of genetic resistance remain poorly understood. Here, we used genotyping by sequencing (GBS) data representing a reduced representation of the genome, to investigate Australian rabbit populations. Our aims were to understand the relationship between populations and identify possible genomic signatures of selection for RHDV resistance. One population we investigated had previously been reported to show levels of resistance to lethal RHDV infection. This population was compared to three other populations with lower or no previously reported RHDV resistance. We identified a set of novel candidate genes that could be involved in host–pathogen interactions such as virus binding and infection processes. These genes did not overlap with previous studies on RHDV resistance carried out in different rabbit populations, suggesting that multiple mechanisms are feasible. These findings provide useful insights into the different potential mechanisms of genetic resistance to RHDV virus which will inform future functional studies in this area. [ABSTRACT FROM AUTHOR]

Maternally inherited Wolbachia transinfections are being introduced into natural mosquito populations to reduce the transmission of dengue, Zika, and other arboviruses. Wolbachia‐induced cytoplasmic incompatibility provides a frequency‐dependent reproductive advantage to infected females that can spread transinfections within and among populations. However, because transinfections generally reduce host fitness, they tend to spread within populations only after their frequency exceeds a critical threshold. This produces bistability with stable equilibrium frequencies at both 0 and 1, analogous to the bistability produced by underdominance between alleles or karyotypes and by population dynamics under Allee effects. Here, we analyze how stochastic frequency variation produced by finite population size can facilitate the local spread of variants with bistable dynamics into areas where invasion is unexpected from deterministic models. Our exemplar is the establishment of wMel Wolbachia in the Aedes aegypti population of Pyramid Estates (PE), a small community in far north Queensland, Australia. In 2011, wMel was stably introduced into Gordonvale, separated from PE by barriers to A. aegypti dispersal. After nearly 6 years during which wMel was observed only at low frequencies in PE, corresponding to an apparent equilibrium between immigration and selection, wMel rose to fixation by 2018. Using analytic approximations and statistical analyses, we demonstrate that the observed fixation of wMel at PE is consistent with both stochastic transition past an unstable threshold frequency and deterministic transformation produced by steady immigration at a rate just above the threshold required for deterministic invasion. The indeterminacy results from a delicate balance of parameters needed to produce the delayed transition observed. Our analyses suggest that once Wolbachia transinfections are established locally through systematic introductions, stochastic "threshold crossing" is likely to only minimally enhance spatial spread, providing a local ratchet that slightly—but systematically—aids area‐wide transformation of disease‐vector populations in heterogeneous landscapes. [ABSTRACT FROM AUTHOR]

Co-distributed taxa can respond both similarly or differently to the same climatic and geological events, resulting in a range of phylogeographic patterns across the region. Using a nested approach on a taxonomically diverse yet morphologically conservative group of agamid lizards, we first aimed to evaluate more precisely the extent of phylogeographic structuring within the genus. Then, focusing on four lineages within the more widespread species, we assessed the impact of biogeographic barriers on phylogeographic structuring and demographic history of species, comparing to patterns previously observed in co-distributed taxa. These species occur in the Australian Monsoonal Tropics, a vast tropical savanna system with high richness and endemism associated with environmental heterogeneity and past climate fluctuations. The employment of genomic data helped to determine the relationships between specific taxa that were previously difficult to place. We found a local influence of biogeographic and climatic breaks on population dynamics, analogous to other species. We detected high levels of population structure in the West Kimberley and Arnhem Plateau, which are already known for high endemism. However, we also highlighted unique lineages in areas that have been overlooked until recently, in the South Kimberley and West Top End. Climatic and geographical features in the Arnhem Plateau act as a soft barrier between populations in the east and west regions of the Top End. These observations reflect patterns observed for other vertebrates across this rich biome, indicating how climatic variation, species' ecology, and landscape features interact to shape regional diversity and endemism., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Genetic diversity, population delineation and rates of gene flow can be used to help understand long-term population dynamics, which is important for conserving species with fragmented distributions. Here, we sequenced 19 nuclear introns (nuDNA) and a portion of mitochondrial DNA (mtDNA) across three subspecies of Pacific Black Ducks (Anas superciliosa ssp.; NmtDNA = 162; NnuDNA = 49) from Australia and surrounding islands in order to measure levels of genetic structure and gene flow. First, despite evidence of gene flow from Australia, Pacific Black Ducks from the Solomon Islands were significantly differentiated from all other groups in both mtDNA and nuDNA. This is probably due to genetic drift resulting in lowered genetic diversity. We found the lowest levels of genetic differentiation between locations sampled in Australia, suggesting strong connectivity across the continent. Despite elevated differentiation in mtDNA between Australia and other islands (i.e. Timor, New Zealand), low nuDNA divergence suggests some connectivity. Such marker discord is common among waterfowl and is likely due to male-biased dispersal from Australia. Finally, mtDNA of Pacific Black Ducks from New Zealand showed introgression of haplotypes from feral mallards (A. platyrhynchos), which were established in the 1800s. Overall, these data suggest that A. superciliosa ssp. consist of three distinct genetic units that correspond with subspecies classifications and require individual conservation planning. [ABSTRACT FROM AUTHOR]

Restoring degraded landscapes has primarily focused on re‐establishing native plant communities. However, little is known with respect to the diversity and distribution of most key revegetation species or the environmental and anthropogenic factors that may affect their demography and genetic structure. In this study, we investigated the genetic structure of two widespread Australian legume species (Acacia salicina and Acacia stenophylla) in the Murray–Darling Basin (MDB), a large agriculturally utilized region in Australia, and assessed the impact of landscape structure on genetic differentiation. We used AFLP genetic data and sampled a total of 28 A. salicina and 30 A. stenophylla sampling locations across southeastern Australia. We specifically evaluated the importance of four landscape features: forest cover, land cover, water stream cover, and elevation. We found that both species had high genetic diversity (mean percentage of polymorphic loci, 55.1% for A. salicina versus. 64.3% for A. stenophylla) and differentiation among local sampling locations (A. salicina: ΦPT = 0.301, 30%; A. stenophylla: ΦPT = 0.235, 23%). Population structure analysis showed that both species had high levels of structure (6 clusters each) and admixture in some sampling locations, particularly A. stenophylla. Although both species have a similar geographic range, the drivers of genetic connectivity for each species were very different. Genetic variation in A. salicina seems to be mainly driven by geographic distance, while for A. stenophylla, land cover appears to be the most important factor. This suggests that for the latter species, gene flow among populations is affected by habitat fragmentation. We conclude that these largely co‐occurring species require different management actions to maintain population connectivity. We recommend active management of A. stenophylla in the MDB to improve gene flow in the adversity of increasing disturbances (e.g., droughts) driven by climate change and anthropogenic factors. [ABSTRACT FROM AUTHOR]

Colletotrichum tanaceti, the causal agent of anthracnose, is an emerging pathogen of commercially grown pyrethrum (Tanacetum cinerariifolium) in Australia. A microsatellite marker library was developed to understand the spatio-genetic structure over three sampled years and across two regions where pyrethrum is cultivated in Australia. Results indicated that C. tanaceti was highly diverse with a mixed reproductive mode; comprising both sexual and clonal reproduction. Sexual reproduction of C. tanaceti was more prevalent in Tasmania than in Victoria. Little differentiation was observed among field populations likely due to isolation by colonization but most of the genetic variation was occurring within populations. C. tanaceti was likely to have had a long-distance gene and genotype flow among distant populations within a state and between states. Anthropogenic transmission of propagules and wind dispersal of ascospores are the most probable mechanisms of longdistance dispersal of C. tanaceti. Evaluation of putative population histories suggested that C. tanaceti most likely originated in Tasmania and expanded from an unidentified host onto pyrethrum. Victoria was later invaded by the Tasmanian population. With the mixed mode of reproduction and possible long-distance gene flow, C. tanaceti is likely to have a high evolutionary potential and thereby has ability to adapt to management practices in the future. [ABSTRACT FROM AUTHOR]

Freshwater fishes often exhibit high genetic population structure due to the prevalence of dispersal barriers (e.g., waterfalls) whereas population structure in diadromous fishes tends to be weaker and driven by natal homing behaviour and/or isolation by distance. The Australian smelt (Retropinnidae: Retropinna semoni) is a native fish with a broad distribution spanning inland and coastal drainages of south-eastern Australia. Previous studies have demonstrated variability in population genetic structure and movement behaviour (potamodromy, facultative diadromy, estuarine residence) across the southern part of its geographic range. Some of this variability may be explained by the existence of multiple cryptic species. Here, we examined genetic structure of populations towards the northern extent of the species’ distribution, using ten microsatellite loci and sequences of the mitochondrial cyt b gene. We tested the hypothesis that genetic connectivity among rivers should be low due to a lack of dispersal via the marine environment, but high within rivers due to dispersal. We investigated populations corresponding with two putative cryptic species, SEQ-North (SEQ-N), and SEQ-South (SEQ-S) lineages occurring in south east Queensland drainages. These two groups formed monophyletic clades in the mtDNA gene tree and among river phylogeographic structure was also evident within each clade. In agreement with our hypothesis, highly significant overall FST values suggested that both groups exhibit very low dispersal among rivers (SEQ-S FST = 0.13; SEQ-N FST= 0.27). Microsatellite data indicated that connectivity among sites within rivers was also limited, suggesting dispersal may not homogenise populations at the within-river scale. Northern groups in the Australian smelt cryptic species complex exhibit comparatively higher among-river population structure and smaller geographic ranges than southern groups. These properties make northern Australian smelt populations potentially susceptible to future conservation threats, and we define eight genetically distinct management units along south east Queensland to guide future conservation management. The present findings at least can assist managers to plan for effective conservation and management of different fish species along coastal drainages of south east Queensland, Australia. [ABSTRACT FROM AUTHOR]

Freshwater fishes often exhibit high genetic population structure due to the prevalence of dispersal barriers (e.g., waterfalls) whereas population structure in diadromous fishes tends to be weaker and driven by natal homing behaviour and/or isolation by distance. The Australian smelt (Retropinnidae: Retropinna semoni) is a native fish with a broad distribution spanning inland and coastal drainages of south-eastern Australia. Previous studies have demonstrated variability in population genetic structure and movement behaviour (potamodromy, facultative diadromy, estuarine residence) across the southern part of its geographic range. Some of this variability may be explained by the existence of multiple cryptic species. Here, we examined genetic structure of populations towards the northern extent of the species' distribution, using ten microsatellite loci and sequences of the mitochondrial cyt b gene. We tested the hypothesis that genetic connectivity among rivers should be low due to a lack of dispersal via the marine environment, but high within rivers due to dispersal. We investigated populations corresponding with two putative cryptic species, SEQ-North (SEQ-N), and SEQ-South (SEQ-S) lineages occurring in south east Queensland drainages. These two groups formed monophyletic clades in the mtDNA gene tree and among river phylogeographic structure was also evident within each clade. In agreement with our hypothesis, highly significant overall FST values suggested that both groups exhibit very low dispersal among rivers (SEQ-S FST = 0.13; SEQ-N FST = 0.27). Microsatellite data indicated that connectivity among sites within rivers was also limited, suggesting dispersal may not homogenise populations at the within- river scale. Northern groups in the Australian smelt cryptic species complex exhibit comparatively higher among-river population structure and smaller geographic ranges than southern groups. These properties make northern Australian smelt populations potentially susceptible to future conservation threats, and we define eight genetically distinct management units along south east Queensland to guide future conservation management. The present findings at least can assist managers to plan for effective conservation and management of different fish species along coastal drainages of south east Queensland, Australia. [ABSTRACT FROM AUTHOR]

Blue swimmer crab species are widely distributed in Indian and west Pacific Oceans including the coastline around Australia and have been identified as potential candidates for stock enhancement. A recent taxonomic review revealed the presence of two blue swimmer crab species in Australia, namely Portunus armatus which is found around most of the Australian coastline, and Portunus pelagicus which is found in the northern coast where it is sympatric with P. armatus. It is important to understand population structure and genetic diversity of Portunus spp. to efficiently manage stocks. In the present study we investigated species classification and population structure of Portunus spp. in Australia using full and partial genomic information, namely mitochondrial COX1 gene sequences derived from whole genome sequencing and single nucleotide polymorphic (SNP) markers developed from partial genome sequencing. Blue swimmer crab samples were collected from the western (n = 52), northern (n = 17) and eastern (n = 110) coasts of Australia. Genetic diversity and population genetic structure were assessed for within and between region variation. Our genomic results indicated the presence of two blue swimmer crab species in Australia. One, namely, P. pelagicus was found only in Northern Territory (Darwin), and other, namely P. armatus was found around Australia. There was evidence of natural hybridisation between two species in Northern Territory (Darwin) where they were sympatric. P. armatus populations from the western, northern and eastern regions were genetically different although there were no significant genetic differences observed between the Queensland and New South Wales populations nor between the two neighbouring populations in Western Australia. Results found in the present study supports the view that the P. armatus populations in western, northern and eastern regions of Australia should be treated as at least three different stocks. A lack of genetic structuring along the eastern coast suggests blue swimmer crabs can be considered as a single stock along the sampled range at least in relation to fisheries enhancement, release programs and broodstock management. • Genomic analyses indicated presence of two blue swimmer crab species in Australia. • There is evidence for natural hybrids between Portunus pelagicus and P. armatus. • We determined the population structure of P. armatus using SNPs. • P. armatus in the west, north and east Australian coasts are genetically different. • There were no significant genetic differences among eastern P. armatus populations. [ABSTRACT FROM AUTHOR]

The koala (Phascolarctos cinereus) suffered population declines and local extirpation due to hunting in the early 20th century, especially in southern Australia. Koalas were subsequently reintroduced to the Brisbane Ranges (BR) and Stony Rises (SR) by translocating individuals from a population on French Island descended from a small number of founders. To examine genetic diversity and north- south differentiation, we genotyped 13 microsatellite markers in 46 wild koalas from the BR and SR, and 27 Queensland koalas kept at the US zoos. The Queensland koalas displayed much higher heterozygosity (HO = 0.73) than the 2 southern Australian koala populations examined: HO = 0.49 in the BR, whereas HO = 0.41 in the SR. This is consistent with the historical accounts of bottlenecks and founder events affecting the southern populations and contrasts with reports of high genetic diversity in some southern populations. The 2 southern Australian koala populations were genetically similar (FST = 0.018, P = 0.052). By contrast, northern and southern Australian koalas were highly differentiated (FST = 0.27, P < 0.001), thereby suggesting that geographic structuring should be considered in the conservation management of koalas. Sequencing of 648 bp of the mtDNA control region in Queensland koalas found 8 distinct haplotypes, one of which had not been previously detected among koalas. Queensland koalas displayed high mitochondrial haplotype diversity (H = 0.753) and nucleotide diversity (p = 0.0072), indicating along with the microsatellite data that North American zoos have maintained high levels of genetic diversity among their Queensland koalas. [ABSTRACT FROM AUTHOR]

The small carpenter bees, genus Ceratina, are highly diverse, globally distributed, and comprise the sole genus in the tribe Ceratinini. Despite the diversity of the subgenus Neoceratina in the Oriental and Indo- Malayan region, Ceratina (Neoceratina) australensis is the only ceratinine species in Australia. We examine the biogeography and demography of C. australensis using haplotype variation at 677 bp of the barcoding region of COI for specimens sampled from four populations within Australia, across Queensland, New South Wales, Victoria and South Australia. There is geographic population structure in haplotypes, suggesting an origin in the northeastern populations, spreading to southern Australia. Bayesian Skyline Plot analyses indicate that population size began to increase approximately 18,000 years ago, roughly corresponding to the end of the last glacial maximum. Population expansion then began to plateau approximately 6,000 years ago, which may correspond to a slowing or plateauing in global temperatures for the current interglacial period. The distribution of C. australensis covers a surprisingly wide range of habitats, ranging from wet subtropical forests though semi-arid scrub to southern temperate coastal dunes. The ability of small carpenter bees to occupy diverse habitats in ever changing climates makes them a key species for understanding native bee diversity and response to climate change. [ABSTRACT FROM AUTHOR]

Understanding the distribution of genetic diversity in exploited species is fundamental to successful conservation. Genetic structure and the degree of gene flow among populations must be assessed to design appropriate strategies to prevent the loss of distinct populations. The cephalopod Nautilus pompilius is fished unsustainably in the Philippines for the ornamental shell trade and has limited legislative protection, despite the species' recent dramatic decline in the region. Here, we use 14 microsatellite markers to evaluate the population structure of N. pompilius around Australia and the Philippines. Despite their relative geographical proximity, Great Barrier Reef individuals are genetically isolated from Osprey Reef and Shark Reef in the Coral Sea ( FST = 0.312, 0.229, respectively). Conversely, despite the larger geographical distances between the Philippines and west Australian reefs, samples display a small degree of genetic structure ( FST = 0.015). Demographic scenarios modelled using approximate Bayesian computation analysis indicate that this limited divergence is not due to contemporary gene flow between the Philippines and west Australia. Instead, present-day genetic similarity can be explained by very limited genetic drift that has occurred due to large average effective population sizes that persisted at both locations following their separation. The lack of connectivity among populations suggests that immigrants from west Australia would not facilitate natural recolonization if Philippine populations were fished to extinction. These data help to rectify the paucity of information on the species' biology currently inhibiting their conservation classification. Understanding population structure can allow us to facilitate sustainable harvesting, thereby preserving the diversity of genetically distinct stocks. [ABSTRACT FROM AUTHOR]

Otolith morphometrics and shape analyses were used to delineate the sub-population structure and determine the level of mixing of southern garfish in South Australian waters. Adult garfish from the 2+ age class were collected from three sites within each of six regions along the South Australian coast: Northern Gulf St Vincent, Southwest Gulf St Vincent, Kangaroo Island, Northern Spencer Gulf, Southern Spencer Gulf and the West Coast of Eyre Peninsula. This study adopted a multi-stage statistical approach exploring the spatial variation in gross otolith morphology and through elliptical Fourier analysis separately, and in combination, over both broad (regional) and fine (site) spatial scales. Stepwise discriminant function analysis revealed significant separation across both spatial scales; however, overall classification success of garfish to their site of capture was poor (<45%). Despite this, the results indicated some level of structuring within South Australia's southern garfish population, as fish were correctly classified at rates that were 32% better than would be expected by chance. At least six putative regional components with various levels of intermixing were detected based on differences in otolith shape. This result refines the spatial resolution of the fishery and consequently highlights the vulnerability of these regional components to localized depletion, particularly as the resource is currently considered to be over-exploited. [ABSTRACT FROM PUBLISHER]

ABSTRACT An 8-year study of the foraging abundance of an Eretmochelys imbricata aggregation, found on 13 reefs (Howick Group) within the northern section of the Great Barrier Reef Marine Park was undertaken., A Cormack-Jolly-Seber method within program MARK was used to: (1) compare survival and recapture probabilities among age and sex classes of turtles; and (2) estimate survival and recapture rates for male and female adults and sub-adults from 665 capture-mark-recapture profiles of E. imbricata., Mean annual population density estimates were consistently greater for adult female E. imbricata (n = 333.7; SD = 135.6; R = 221-581) than for adult males (n = 32.4; SD = 33.4; R = 8-98), with both adult males and females displaying high survivorship rates (71.1%; 92.2%, respectively). This was also apparent in immature age-classes, with male and female turtles showing similarly high survivorship likelihoods (78.0%; 93.0%, respectively)., Both sexes exhibited a similar overall trend with a peak population density being displayed in the first two years of the study, followed by a general decline in the female stock and stable male population., These are the only reliable long-term abundance time-series data for a population that includes all age-classes of E. imbricata in the western Pacific and provide good baseline data for the detection of possible climate change induced trends., Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses findings of a study which analyzed the population structure of southern right whales on calving grounds across New Zealand and Australia using mitochondrial deoxyribonucleic acid (mtDNA) control region haplotypes and microsatellite genotypes. The two stocks of recovering southern right whales based on historical migration patterns and spatially variable patterns are NZ, comprising New Zealand (NZ) subantarctic (NZSA) and mainland NZ (MNZ) stocks, and the southwest and southeast stocks from Australia. Based on a comparison of mtDNA haplotype frequencies, there was structuring of maternal lineages on southern right whale calving grounds across NZ and Australia.

India is the largest grower of Eucalyptus with an area of 3.943 million hectares under plantations and E. tereticornis is the predominant species in the plains of southern India with an average productivity of 12–25 m3 ha−1 year−1. With the aim to establish seedling seed orchards of the species, seed lots of fifteen provenances were imported from Australia and a trial was laid. In the present study the genetic diversity existing in the seed orchard was estimated using ISSR–PCR. Seven ISSR primers amplified 663 amplicons in the size ranging from 255 to 2,711 bp. The total number of polymorphic bands varied from 59 to 123 with 100% polymorphic banding profiles. The average gene diversity ( Hj) of all the provenances ranged from 0.0589 to 0.1109 and the total gene diversity estimated was low ( HT = 0.130) when compared to the earlier reports from other eucalypts species. Analysis of Molecular Variance partitioned the ISSR variation into inter and intra population components. The inter population component accounted for 55.2% of the variation and the intra population component accounted for 46.3% ( P < 0.001). A neighbour-joining analysis was done using the dissimilarity matrix to determine the aggregation of the individuals into clusters. Existence of population structure among the populations was revealed in STRUCTURE analysis but geographical region based clustering was not observed. The assessment of intra and inter genetic variation documented in the present study suggests that, along with the phenotypic traits, knowledge about genetic diversity measured at the DNA level in individuals of seed orchards provide an objective guide for selective culling of trees for maintaining optimal diversity for enhanced genetic gains. [ABSTRACT FROM AUTHOR]

Genetic variation, and the way in which it is partitioned among populations, has implications for a species' survival and evolutionary potential. Such information is particularly important for the successful conservation and management of species that have experienced past human impacts and potential losses of genetic diversity. Overharvesting of the Australian fur seal Arctocephalus pusillus doriferus in the 18th and 19th centuries resulted in severe population reductions and elimination of an estimated 17 of 26 colonies. Currently, the subspecies is recovering and c. 20 000 pups are produced annually at 13 colony sites, most of which are situated in Bass Strait in south-eastern Australia. Genetic analysis of samples collected from pups captured at nine colonies revealed no difference in allelic diversity or heterozygosity at five microsatellite loci and no differences in haplotype diversity within a 344 bp region of the mitochondrial DNA control region. There was some evidence for isolation by distance but the programstructure predicted a single cluster of individuals. Gene flow among colonies appears to be substantial at present, indicating that the Australian fur seal is currently a single, panmictic unit. [ABSTRACT FROM AUTHOR]

Abstract: Since its introduction in Australia, and despite decades of movement control, the cattle tick, Rhipicephalus (Boophilus) microplus, has spread widely in suitable habitat in the Northern Territory and the state of Queensland (QLD). On the east coast, its southerly distribution is limited by a tick quarantine line on the border with the state of New South Wales (NSW). Resistance to the popular acaricide amitraz emerged in the early 1980s and its distribution is rapidly increasing at the present time. This study examines the genetic structure of amitraz-resistant and susceptible populations in Queensland and the relationship of endemic populations in the state of Queensland with outbreak populations in the state of New South Wales. Ticks from paired susceptible and resistant field isolates were collected from five locations, including outbreak populations south of the quarantine line, and, following resistance testing, larvae were genotyped using 13 microsatellites. Three of the four populations located south of the tick quarantine line showed low variability (H o 0.48; with 2.36–3.55 alleles per locus), presumably as a result of strong founder effects and genetic drift. All Queensland populations showed high variability (H o 0.67–0.74; with 7.00–9.82 alleles per locus) yet even these populations showed evidence of past bottlenecks, a likely consequence of the use of acaricides. Reduced gene flow at distances as low as 4.2km was indicated by significant differentiation of most populations. However, local selective effects on resistance alleles in the absence of gene flow cannot be discarded as an explanation. There was no clear pattern of differentiation by region or by resistance status. [Copyright &y& Elsevier]

Information on the movements and population structure of an exploited fish species is vital for determining the appropriate spatial scale at which management should occur to ensure sustainable harvesting. However, such information exists for very few exploited species. Large-scale patterns and drivers of movement were examined for an iconic recreational sciaenid species, mulloway (Argyrosomus japonicus), in coastal eastern Australia using an angler-assisted tag-recapture dataset. Over 4300 individuals were tagged and released across 1005 km of coastline over three decades (1988–2017). Six-hundred and fifty-seven individuals were subsequently recaptured at a rate of 15.1% over the same time period. Average time at liberty was 216 (±9) days (range: 0–1954 days), with distances moved ranging from 0 to 355 km. Median movement distance was 4 km, and a large proportion of individuals (73%) were recaptured within 10 km of release locations. Thirty one percent of individuals were recaptured at release locations (< 1 km) and 81% in the same estuary. However, 7% moved distances of > 100 km. Generalised additive modelling revealed that release latitude, body size and time at liberty were significant predictors of distance moved. Greater distances moved were observed for fish tagged at lower latitudes, at larger sizes and over longer periods at liberty. Results indicate that A. japonicus are primarily restricted to small movements (< 10 km) in eastern Australia and display strong site fidelity, despite being capable of movements over larger scales (100s of km). This spatial scale of movement is also much smaller than the current 'jurisdictional' scale of management in this region (~1000 km). Assessment and management of A. japonicus in eastern Australia may therefore need to be re-examined considering these findings and potentially undertaken at more localised spatial scales in the future. This study also highlights the importance of citizen science in the cost-effective generation of a sufficiently broad spatio-temporal dataset required to detect the movement patterns revealed here. • Released over 1000 km and three decades, tagged Argyrosomus japonicus were recaptured at a rate of 15.1%. • Movements occurred predominantly over small spatial scales (< 10 km) in eastern Australia. • Fish tagged at lower latitudes, at larger sizes and over longer periods at liberty moved greater distances. • Current spatial management of the stock may consequently need to be re-examined. • Citizen science was key in the cost-effective generation of the large-scale tagging dataset used. [ABSTRACT FROM AUTHOR]

We report the characterization of eight microsatellite markers in the big-headed ant Pheidole megacephala, a pest ant registered in the list of ‘100 of the world's worst invasive alien species’. An enrichment protocol was used to isolate microsatellite loci, and polymorphism was explored with 36 individuals collected in an invasive population from Australia and 20 individuals collected in a population from the native mainland location in South Africa. These primers showed a number of alleles per locus ranging from two to 10, and expected heterozygosities ranging from 0.083 to 0.826. Moreover, results of cross-species amplification are reported in five other Pheidole species and in seven other ants of the subfamily Myrmicinae. [ABSTRACT FROM AUTHOR]

Examples of irregular development (diapause regimes) are reported in three families (Lycaenidae, Nymphalidae, Papilionidae) of butterflies in Australia. The importance of understanding such irregularities is emphasized, and their relevance to interpreting conservation status and needs discussed. Expectations of incidence or abundance may not be met, and unexpected declines or losses resulting from irregular diapause can cause unnecessary conservation concerns. [ABSTRACT FROM AUTHOR]

Feral pigs (Sus scrofa) are an invasive species in Australia. Their negative impact on conservation values has been demonstrated, and they are controlled in many areas in the rangelands of Australia. However, they are usually controlled over small, often ad hoc management units (MUs), and previous research has revealed that these MUs can be inadequate. Understanding feral pig population structuring can aid in the design of appropriate MUs. This study documents an approach to improving MUs for feral pig control in the rangelands of Australia. Feral pigs from a 500,000 km2 region were genotyped with 13 polymorphic markers. Genetic analyses were used to identify population structure. Identified sub-populations were then related to geographical and environmental gradients with geographical information systems, regression analysis and with canonical correspondence analysis. Five sub-populations were identified. These were moderately differentiated, with relatively high-migration rates. Two sub-populations in drier, lower elevation areas overlapped, due to extensive migration, probably along the large, inland rivers and flood plains. Sub-populations in higher rainfall environments appeared less likely to migrate. Sub-population differentiation was also dependant on distance, indicating isolation by distance was present. A case study applying an adaptive MU to a previously controlled area is presented. Generally, however, MUs for feral pig control for natural resource protection and endemic disease eradication in the rangelands should take into account geographical size, but also geographic features, especially major rivers in low-rainfall areas. [ABSTRACT FROM AUTHOR]

Aim Recent genetic and ecological studies of marine invertebrate species with planktotrophic larvae have inferred high rates of gene flow across wide oceanic barriers. We therefore aim to test for the genetic signature of long-distance dispersal in two widespread and abundant marine gastropod taxa. Location The intertidal and shallow subtidal zones of southern Australia and New Zealand (NZ), which house similar marine invertebrate assemblages despite being separated by the 2000-km-wide Tasman Sea. Methods We used mtDNA cytochrome oxidase I gene sequence analysis of two gastropod genera exhibiting trans-Tasman distributions, namely Austrolittorina (Littorinidae) (139 specimens; 28 localities) and Scutus (Fissurellidae) (154 specimens; 32 localities). The cool-temperate Australian ( A. unifasciata; S. antipodes) and NZ ( A. antipodum; S. breviculus) taxa within each genus are morphologically similar but of uncertain taxonomic status. Results The mtDNA analyses indicate major trans-Tasman genetic discontinuities for both gastropod genera, with no evidence of recent or ongoing intercontinental gene flow. Although both Scutus and Austrolittorina show significant east–west structure within southern Australia – consistent with recent studies of regional marine phylogeography – neither taxon exhibits significant differentiation within NZ. Main conclusions Morphologically conserved but biogeographically disjunct gastropod populations may exhibit striking phylogeographic discontinuities, even when dispersal abilities appear to be high. On the basis of these data we reject recent calls for the synonymy of NZ and Australian lineages. [ABSTRACT FROM AUTHOR]

Recent studies suggest that populations of the pest moth Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) may be genetically differentiated over short distances and time periods within Queensland, Australia. To test for genetic structure in another region of Australia, we characterized population differentiation in Victorian samples of H. armigera using eight microsatellite loci. We found no evidence of genetic structure among samples from different locations or among samples collected at different times. Moreover, Victorian samples were not differentiated from other samples of H. armigera from Queensland and New Zealand. All samples showed substantial deviations from Hardy–Weinberg equilibrium, suggesting a high frequency of null alleles typically found in microsatellites of Lepidoptera. These results indicate that populations of H. armigera are not strongly structured among regions in south-eastern Australia. [ABSTRACT FROM AUTHOR]

The green and golden bell frog (Litoria aurea) has a widespread distribution along the south-east coast of Australia. The species range, however, is highly fragmented and remaining populations are predominately isolated and restricted to the coastline. Previously, the range extended further inland and the species was considered common. Here we report a study designed to identify the phylogeographic and conservation genetic parameters of L. aurea. Mitochondrial DNA sequences were examined from 263 individuals sampled from 26 locations using both phylogenetic and population analyses. Despite a general consensus that amphibians are highly structured we found no phylogeographic divisions within the species, however, there was significant structure amongst extant populations (FST=0.385). Patterns of haplotype relatedness, high haplotypic diversity (mean h=0.547) relative to low nucleotide diversity (mean p=0.003) and mismatch distribution analysis supported a Pleistocene expansion hypothesis with continued restricted dispersal and gene flow. We conclude that the genetic structure of the species may permit 'well managed' intervention to mediate gene flow amongst isolated populations and provide some guidelines for the implementation of such conservation strategies. [ABSTRACT FROM AUTHOR]

Opportunistic sampling suggested a complex population structure for Squalus megalops in southeastern Australia. A total of 929 sharks were analyzed. The sex ratio was biased towards females and there was sexual size dimorphism, with females attaining a larger maximum size than males. Individual analysis of selected fishing shots suggested that S. megalops had a complex population structure, and was segregated by sex, size and breeding condition. Small females and males segregated from large females. In addition, large females in the first year of pregnancy seemed to be separated from those in the second year of pregnancy. [ABSTRACT FROM AUTHOR]

Populations of Australian diamondback moth (DBM) Plutella xylostella (L.), a serious pest of cruciferous crops, display extremely low levels of genetic differentiation across Australia and New Zealand sample locations, as determined previously using microsatellite markers. These data suggest high levels of contemporary gene flow that is consistent with Australian DBM being a vagile species. Here we examine Australian DBM samples for haplotype variation using the mitochondrial DNA sequences of a 257 bp fragment of the CO1 gene. We compare this variation to equivalent mtDNA sequence variation in samples from New Zealand, Kenya and Korea. Using 42 moths collected throughout Australia we show that Australian DBM have both low mtDNA haplotype and nucleotide diversities. The three Australian haplotypes detected are closely related and they cluster with the common haplotype group from Indonesia. In addition the Australian haplotype frequency distribution resembled more that from Indonesia than that from Kenya or Korea. These data are consistent with an original strong Australian/New Zealand founder effect, from a south-eastern Asian source, with subsequent continued isolation. In a single season, the frequency of PXMt01, the most common Australian haplotype, was estimated at 15 locations spread across southern Australia and New Zealand using a polymerase chain reaction BiPASA method. The PXMt01 haplotype frequency variation was heterogenous, suggesting a small degree of population isolation that was not detected using microsatellites. Differentiation was not a function of geographical distance. These data suggest transient and sporadic local colonisation events by small numbers of founding females. [ABSTRACT FROM AUTHOR]

We present research undertaken at Tallaganda State Forest, Australia, describing how current climatic conditions impact upon the saproxylic (decaying wood) habitat and the relationship between this habitat and the demography and morphology of a saproxylic funnelweb spider ( Hadronyche sp.). Climatic data support a north–south habitat cline and, to a lesser extent, a short-range, aspect-driven habitat cline. Rainfall and log moisture content increased with latitude through the forest, and aspect affected the amount of solar radiation penetrating to ground level. The distribution and abundance of Hadronyche varied among sites along both clines in response to several variables. The decay state of logs was highly influential, with wet, highly decayed logs favoured over dry, hard ones. Population density was highest in wetter, southern sites where these logs were abundant, but rare, suitably decomposed logs in dry, northern sites still typically hosted a comparable number of individuals. Morphological measurements showed some phenotypic variation along the north–south habitat gradient, but not over the short-range, aspect-driven gradients. Hadronyche would not be expected to show similarly strong patterns of molecular variation as seen in saproxylic Collembola and Onychophora within Tallaganda as it appears to be more vagile. [ABSTRACT FROM AUTHOR]

The diamondback moth, Plutella xylostella, is renowned for developing resistance to insecticides and causing significant economic damage to Brassica vegetable crops throughout the world. Yet despite its economic importance, little is known about the population structure and movement patterns of this pest both at local and regional scales. In Australia, the movement patterns and insecticide resistance status of P. xylostella infesting canola, vegetables, forage brassicas and weeds have fundamental implications for the management of this pest. Here we use six polymorphic microsatellite loci to investigate population structure and gene flow in Australian populations of P. xylostella. Samples of P. xylostella from New Zealand, Malaysia, Indonesia and Kenya were also scored at these loci. We found no evidence of population structure within Australia, with most populations having low inbreeding coefficients and in Hardy–Weinberg equilibrium. In addition, a sample from the North Island of New Zealand was indistinguishable from the Australian samples. However, large genetic differences were found between the Australia/New Zealand samples and samples from Kenya, Malaysia and Indonesia. There was no relationship between genetic distance and geographic distance among Australian and New Zealand samples. Two of the loci were found to have null alleles, the frequency of which was increased in the populations outside the Australia/New Zealand region. We discuss these results with reference to insecticide resistance management strategies for P. xylostella in Australia. [ABSTRACT FROM AUTHOR]

The green and golden bell frog ( Litoria aurea) was once a common Australian Hylid. Today, many populations are small and fragmented as a result of dramatic declines in distribution and abundance. We undertook a large-scale assessment of genetic structure and diversity in L. aurea using four species-specific microsatellite markers. Twenty-one locations were sampled from throughout the species range covering 1000 km of the east coast of Australia. Levels of allelic diversity and heterozygosity were high (uncorrected mean alleles/locus and HE were 4.8–8.8 and 0.43–0.8, respectively) compared to other amphibian species and significant differences among sampled sites were recorded. Despite recent population declines, no sites displayed a genetic signature indicative of a population bottleneck. Significant genetic structuring (overall FST 0.172) was detected throughout the species range, but was relatively low compared to previous amphibian studies employing microsatellites. In addition we found that some areas sampled within continuous habitat showed evidence of weak genetic structuring (data subset FST 0.034). We conclude that maintaining areas of continuous habitat is critical to the conservation of the species and argue that population recovery and/or persistence in all areas sampled is possible if appropriate protection and management are afforded. [ABSTRACT FROM AUTHOR]

In fragmented woodlands in agricultural regions of Australia, roadside environments (road verges) provide important refuges for threatened native fauna and isolated populations of plant species. However, as roads are transport corridors for humans and their vehicles, species survival is affected through destruction, fragmentation and modification of remaining habitat by human activity. Few studies have recognised the effects of anthropogenic disturbances, in the form of historical roadworks activities, on adjacent roadside plant populations. The aim of this study was to investigate the effects of soil disturbance from roadworks on the spatial patterns and structural dynamics of roadside Acacia populations in an agricultural area in southeastern Australia. Stem size and disturbance data were collected from 135 roadside populations of three species of Acacia shrubs in the Lockhart Shire area. Spatial pattern analysis using the Network K-function and Discriminant Function analyses showed that road verge width, road category, disturbance intensity and distance to nearest town were highly significant variables in relation to disturbance from roadworks and shrub structural dynamics. Colonising populations were more abundant along gravel roads where soil disturbance intensity was high, whereas stable populations were more abundant where soil disturbance intensity was low. Senescent populations were more abundant in narrow, little used road verge corridors 4-6 km from nearby towns. These results suggest that anthropogenic disturbance regimes may be critical to shrub recruitment and persistence in roadside environments, which has important consequences for conservation of threatened native flora and fauna in agricultural landscapes. [ABSTRACT FROM AUTHOR]

SUMMARY 1. The freshwater prawn, Macrobrachium australiense (Decapoda: Palaemonidae), is an abundant species throughout the rivers of western Queensland, and it is thought to have effective dispersal capabilities. Given the very low topographical relief of the western Queensland landscape and the vast nature of episodic flooding, it was predicted that widespread dispersal in this species would occur within, and possibly between the four major catchments of the region: the Darling, Bulloo, Cooper and Diamantina. We analysed eight polymorphic allozyme systems and a fragment of the cytochrome c oxidase subunit 1 (COI) mitochondrial DNA (mtDNA) gene to determine the extent of recent and historical patterns of dispersal at nested spatial scales, within and between catchments. 2. Large and significant levels of allozyme and mtDNA differentiation were revealed among all catchments, indicating that dispersal of M. australiense does not occur across catchment boundaries, although this species is reportedly capable of overland movement. In contrast, no significant patterns of genetic differentiation were resolved between major subcatchments of the Darling and Cooper, or between sites within these subcatchments, indicating that populations of M. australiense are panmictic within catchments. 3. The MtDNA data resolved two divergent and reciprocally monophyletic clades, with the first representing the Darling catchment, and the second corresponding to the Bulloo, Cooper and Diamantina catchments. We postulate that extreme variation in historical climatic patterns and palaeohydrologic conditions played an important role in shaping the population structure of M. australiense throughout western Queensland during the Quaternary. [ABSTRACT FROM AUTHOR]

Abstract Samples from 83 populations of salt lake Ostracods belonging to the genus Mytilocypris were collected from 74 saline lakes and ponds in the semi-arid regions of Australia. These populations were examined for variation at six polymorphic enzyme loci to diagnose breeding systems and to measure population structure, to investigate relative levels of gene flow in species with differing distributions and hence different presumed dispersal capabilities. Despite the occurrence of some populations in disjunct, peripheral, and recent ephemeral habitats, all populations of each species were found to reproduce sexually. Gene flow does occur on a local basis and appears to be facilitated by occupation in the same drainage basin for some species. There was considerable gene pool fragmentation among peripheral populations of four of the five species. Only one species, M. mytiloides , was relatively homogeneous across its range. It may be that gene flow is non-existent into peripheral populations because of poor dispersal abilities, or it may not be frequent enough to overcome local selective pressures. Regardless of these possibilities, the observed gene pool fragmentation has implications for allopatric speciation. [ABSTRACT FROM AUTHOR]

The genetic population structure of a large, wide-ranging marsupial, the red kangaroo (Macropus rufus) was assessed using sequence and haplotype frequency data of mitochondrial DNA (mtDNA) from locations across the species range in Australia. Results from sequence data revealed extensive haplotype diversity within the red kangaroo (32/34 sequences were unique). Sequence diversity was distributed within rather than between geographical regions across the species range. Genetic connectivity across the range of the species has therefore been maintained over the long term. On a smaller within-region scale, significant genetic structuring was evident from heterogeneity of haplotype frequencies amongst sampling sites. The geographical scale of panmictic populations differed across the continent with more restricted genetic populations occurring in areas with greater topographic and habitat complexity. We propose that these differences in area of genetic populations are the result of population responses to limiting ecological factors during drought. [ABSTRACT FROM AUTHOR]

The yellow-footed rock-wallaby Petrogale xanthopus is considered to be potentially vulnerable to extinction. This wallaby inhabits naturally disjunct rocky outcrops which could restrict dispersal between populations, but the extent to which that occurs is unknown. Genetic differences between populations were assessed using mitochondrial DNA (control region) sequencing and analysis of variation at four microsatellite loci among three geographically close sites in south-west Queensland (P. x. celeris) and, for mtDNA only, samples from South Australia (P. x. xanthopus) as well. Populations from South Australia and Queensland had phylogenetically distinct mtDNA, supporting the present classification of these two groups as evolutionarily distinct entities. Within Queensland, populations separated by 70 km of unsuitable habitat differed significantly for mtDNA and at microsatellite loci. Populations separated by 10 km of apparently suitable habitat had statistically homogeneous mtDNA, but a significant difference in allele frequency at one microsatellite locus. Tests for Hardy-Weinberg equilibrium and micro-geographical variation at microsatellite loci did not detect any substructuring between two wallaby aggregations within a colony encircling a single rock outcrop. Although the present study was limited by small sample sizes at two of the three Queensland locations examined, the genetic results suggest that dispersal between colonies is limited, consistent with an ecological study of dispersal at one of the sites. Considering both the genetic and ecological data, we suggest that management of yellow-footed rock-wallabies should treat each colony as an independent unit and that conservation of the Queensland and South Australian populations as separate entities is warranted. [ABSTRACT FROM AUTHOR]

Black wattle (Acacia mearnsii) has great economic value as a commercial source of tannins, timber and a source of firewood for local and international markets. It has been suggested that to maximize the genetic gain of A. mearnsii plantations in South Africa, the gene pool that exist within ICFR needs to be broadened via introduction of new genotypes with diverse traits. In this work, 282 A. mearnsii samples sourced from the ICFR breeding program were genotyped using 11 cross-species SSR markers. Our results showed low to moderate genetic differentiation (F ST ) among the six breeding subpopulations, with positive inbreeding (F IS ) values that could be attributed to an historical inbreeding event. Low levels of relatedness could however indicate some mechanism of inbreeding avoidance. The effects from a recent supplementation of genetic material from two native Australian populations were observed through genetic structuring analyses. Analysis of molecular variance (AMOVA) revealed that significant genetic variation was mainly distributed within populations (75%) and among individuals (23%). The results provide significant information on A. mearnsii population genetic diversity and structure, which can be used for conservation of the current subpopulations and future tree improvement programs., (© 2021. The Botanical Society of Japan.)

Differences in the geographic scale and depth of phylogeographic structure across codistributed taxa can reveal how microevolutionary processes such as population isolation and persistence drive diversification. In turn, environmental heterogeneity, species' traits, and historical biogeographic barriers may influence the potential for isolation and persistence. Using extensive SNP data and a combination of population genetic summary statistics and landscape genomic analyses, we explored predictors of the scale and depth of phylogeographic structure in codistributed lizard taxa from the topographically and climatically complex monsoonal tropics (AMT) of Australia. We first resolved intraspecific lineages and then tested whether genetic divergence across space within lineages is related to isolation by distance, resistance and/or environment and whether these factors differ across genera or between rock-related versus habitat generalist taxa. We then tested whether microevolutionary processes within lineages explain differences in the geographic scale and depth of intraspecific phylogeographic lineages. The results indicated that landscape predictors of phylogeographic structure differ between taxa. Within lineages, there was prevalent isolation by distance, but the strength of isolation by distance is independent of the taxonomic family, habitat specialization, and climate. Isolation by environment is the strongest predictor of landscape-scale genetic divergence for all taxa, with both temperature and precipitation acting as limiting factors. The strength of isolation by distance does not predict the geographic scale of the phylogeographic structure. However, more localized lineages had higher mean individual heterozygosity and less negative Tajima's D. This result implies that finer-scale phylogeographic structuring within species is associated with larger and more stable populations and, hence, persistence., (© 2021 John Wiley & Sons Ltd.)

Abstract: Juvenile and adult sporophytes of Ecklonia radiata were counted on in-shore and off-shore reefs at Marmion (Perth, Western Australia), across spatial scales of kilometres, 10s of metres and metres. The position on in-shore reefs vs. off-shore reefs did not influence recruit and adult kelp density. There was considerable site-to-site (kilometres) variation in densities of recruits but not adults. The majority of variation in both recruit and adult densities was found between quadrats separated by a few metres. There was no relationship between abundance of recruits and abundance of adult sporophytes at any of the spatial levels of investigation, suggesting a decoupling of recruitment and canopy processes. The results emphasise the patchy nature of kelp canopy distribution and suggest that relatively small-scale processes, acting on scales of a few metres, are of primary importance in generating heterogeneity in the canopy of these kelps. [Copyright &y& Elsevier]