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Climate change is altering species ranges and reproductive interactions in existing ranges, offering species new scope to mate and hybridize. The outcomes will depend on how environmental factors shape reproductive barriers across life stages, yet this is rarely assessed across the environments that species encounter in nature. We assess prezygotic and postzygotic barriers, and their dependence on temperature and parental sex, in species of a reef-building tubeworm (Galeolaria) from a fast-warming biodiversity hotspot in southern Australia. By replicating pure and reciprocal hybrid crosses across 5 temperatures spanning species' thermal ranges, we estimate thermal tolerance curves (defining niches) for crosses and reproductive isolation at each temperature. By also replicating crosses at 3 life stages, we partition the contributions of prezygotic barriers at fertilization, postzygotic barriers at embryogenesis, and postzygotic barriers at larval development to reproductive isolation. We show that barriers are weaker at fertilization and embryogenesis, but stronger and more temperature sensitive at larval development, as species diverge in thermal niche. Asymmetry of barriers between parental sexes, moreover, suggests a complex interplay between niche differentiation and maternal inheritance. Our findings point to a key role for temperature in reproductive isolation, but also challenges for predicting the fate of isolation in future climates. [ABSTRACT FROM AUTHOR]

Phylogeographic studies of continental clades, especially when combined with palaeoclimate modelling, provide powerful insight into how environment drives speciation across climatic contexts. Australia, a continent characterized by disparate modern biomes and dynamic climate change, provides diverse opportunity to reconstruct the impact of past and present environments on diversification. Here, we use genomic‐scale data (1310 exons and whole mitogenomes from 111 samples) to investigate Pleistocene diversification, cryptic diversity, and secondary contact in the Australian delicate mice (Hydromyini: Pseudomys), a recent radiation spanning almost all Australian environments. Across northern Australia, we find no evidence for introgression between cryptic lineages within Pseudomys delicatulus sensu lato, with palaeoclimate models supporting contraction and expansion of suitable habitat since the last glacial maximum. Despite multiple contact zones, we also find little evidence of introgression at a continental scale, with the exception of a potential hybrid zone in the mesic biome. In the arid zone, combined insights from genetic data and palaeomodels support a recent expansion in the arid specialist P. hermannsburgensis and contraction in the semi‐arid P. bolami. In the face of repeated secondary contact, differences in sperm morphology and chromosomal rearrangements are potential mechanisms that maintain species boundaries in these recently diverged species. Additionally, we describe the western delicate mouse as a new species and recommend taxonomic reinstatement of the eastern delicate mouse. Overall, we show that speciation in an evolutionarily young and widespread clade has been driven by environmental change, and potentially maintained by divergence in reproductive morphology and chromosome rearrangements. [ABSTRACT FROM AUTHOR]

Simple Summary: Arboreal mammals provide important ecological services, but they are threatened by many anthropogenic activities, including habitat isolation and fragmentation. We investigated the population dynamics of the Australian squirrel glider in a small and larger reference population over a 16 year period. Population modelling suggests that a decline occurred in the small population but not the larger one. External factors are implicated in the decline and warrant further investigation. Small populations are at high risk of extinction, and they are likely to need management intervention. Successful management, however, relies on sufficient long-term demographic data in order to determine whether apparent declines are natural fluctuations or the product of threatening processes. In this study, we monitored a small urban population of squirrel gliders (Petaurus norfolcensis) in Queensland, Australia, over a 16 year period. A reference population in a larger forest patch was also studied in order to investigate whether its demographic trends were similar. Using mark-recapture data to generate estimates of apparent survival and population size, we found evidence of a decline within the small population but not in the reference population over the monitoring period. We suggest that the influence of multiple factors may have led to the decline, but, ultimately, that the genetic condition of the small population may be responsible. Understanding demographic trends is an important context for management interventions of small populations, although causes of decline need to be identified for successful management. The squirrel glider provides a useful case study for small urban populations and particularly for arboreal mammals. [ABSTRACT FROM AUTHOR]

The genetic relatedness of yeasts in the Saccharomyces bayanus complex has been studied using the methods of molecular and classical genetics. A divergent population of S. bayanus has been found in New Zealand and Australia. The S. bayanus complex includes four genetic populations: S. bayanus var. bayanus, S. bayanus var. uvarum, S. eubayanus, and the New Zealand population. The strains of the New Zealand population differ significantly in the nucleotide sequences of the nuclear (FSY1, HIS3, MET2) and mitochondrial (FUN14, COX2) genes and form semi-sterile hybrids with other populations: the viability of ascospores is 6.2–23.3%. There is no complete interspecific postzygotic isolation among S. bayanus var. bayanus, S. bayanus var. uvarum, S. eubayanus, and the New Zealand populations: all hybrids showed regular meiotic segregation of the control auxotrophic markers. According to the results obtained, the four genetic populations belong to the same biological species with genomic divergence at the level of taxonomic varieties. [ABSTRACT FROM AUTHOR]

Population isolation and concomitant genetic divergence, resulting in strong phylogeographical structure, is a core aspect of speciation initiation. If and how speciation then proceeds and ultimately completes depends on multiple factors that mediate reproductive isolation, including divergence in genomes, ecology and mating traits. Here we explored these multiple dimensions in two young (Plio‐Pleistocene) species complexes of gekkonid lizards (Heteronotia) from the Kimberley–Victoria River regions of tropical Australia. Using mitochondrial DNA screening and exon capture phylogenomics, we show that the rock‐restricted Heteronotia planiceps exhibits exceptional fine‐scale phylogeographical structure compared to the codistributed habitat generalist Heteronotia binoei. This indicates pervasive population isolation and persistence in the rock‐specialist, and thus a high rate of speciation initiation across this geographically complex region, with levels of genomic divergence spanning the "grey zone" of speciation. Proximal lineages of H. planiceps were often separated by different rock substrates, suggesting a potential role for ecological isolation; however, phylogenetic incongruence and historical introgression were inferred between one such pair. Ecomorphological divergence among lineages within both H. planiceps and H. binoei was limited, except that limestone‐restricted lineages of H. planiceps tended to be larger than rock‐generalists. By contrast, among‐lineage divergence in the chemical composition of epidermal pore secretions (putative mating trait) exceeded ecomorphology in both complexes, but with less trait overlap among lineages in H. planiceps. This system—particularly the rock‐specialist H. planiceps—highlights the role of multidimensional divergence during incipient speciation, with divergence in genomes, ecomorphology and chemical signals all at play at very fine spatial scales. [ABSTRACT FROM AUTHOR]

Premise: Whole‐genome duplication is considered a major mechanism of sympatric speciation due to the creation of strong and instantaneous reproductive barriers. Although postzygotic reproductive isolation between diploids and polyploids is often expected, the extent of reproductive incompatibility must be empirically determined and compared to patterns of genetic isolation to fully characterize the reproductive dynamics between cytotypes. Methods: We investigated reproductive compatibility between diploid and tetraploid Lycium australe in two mixed‐cytotype populations using (1) controlled crossing experiments to evaluate fruit and seed production and (2) germination trials to test seed viability following homoploid and heteroploid crosses. We contrast these experiments with a single‐nucleotide polymorphism (SNP) data set to measure genetic isolation between cytotypes and explore whether cytotype or population origin better explains patterns of genetic variation. Finally, we explore mating patterns using the observed germination rates of naturally produced seeds in each population. Results: Although homoploid and heteroploid crosses resulted in similar fruit and seed production, reproductive isolation between co‐occurring diploids and tetraploids was nearly complete, due to low seed viability following heteroploid crosses. Of 191,182 total SNPs, 21,679 were present in ≥90% of individuals and replicate runs using unlinked SNPs revealed strong clustering by cytotype and differentiation of tetraploids based on population origin. Conclusions: As often reported, diploid and tetraploid L. australe experience strong postzygotic isolation via hybrid seed inviability. Consistent with this result, cytotype explained a greater amount of variation in the SNP data set than population origin, despite some evidence of historical introgression. [ABSTRACT FROM AUTHOR]

In the conventional view, species are separate gene pools delineated by reproductive isolation (RI). In an alternative view, species may also be delineated by a small set of 'speciation genes' without full RI, a view that has gained broad acceptance. A recent survey, however, suggested that the extensive literature on 'speciation with gene flow' is mostly (if not all) about exchanges in the early stages of speciation. There is no definitive evidence that the observed gene flow actually happened after speciation is completed. Here, we wish to know whether 'good species' (defined by the 'secondary sympatry' test) do continue to exchange genes and, importantly, under what conditions such exchanges can be observed. De novo whole-genome assembly and re-sequencing of individuals across the range of two closely related mangrove species (Rhizophora mucronata and R. stylosa) reveal the genomes to be well delineated in allopatry. They became sympatric in northeastern Australia but remain distinct species. Nevertheless, their genomes harbor ∼4000–10   000 introgression blocks averaging only about 3–4 Kb. These fine-grained introgressions indicate continual gene flow long after speciation as non-introgressable 'genomic islets,' ∼1.4 Kb in size, often harbor diverging genes of flower or gamete development. The fine-grained introgression in secondary sympatry may help settle the debate about sympatric vs. micro-allopatric speciation. In conclusion, true 'good species' may often continue to exchange genes but the opportunity for detection is highly constrained. [ABSTRACT FROM AUTHOR]

The Australian dingo is a recent anthropogenic addition to the Australian fauna, which spread rapidly across the continent and has since widely interbred with modern dogs. Genetic studies of dingoes have given rise to speculation about their entry to the continent and subsequent biogeographic effects, but few studies of their contemporary population structure have been conducted. Here we investigated the dingo ancestry and population structure of free-living dogs in western Victoria and contrasted it with a wider southern Australian sample. We wished to determine whether their geographic isolation was mirrored in genetic isolation. To address this question, we analysed 34 microsatellite markers using Bayesian clustering and discriminant analysis of principal components, and summarised genetic diversity at the population and individual level. The broader southern Australia sample (n = 1138) comprised mostly hybrid animals, with 30% considered pure dingoes. All western Victorian individuals (n = 59) appeared to be hybrids with high dingo ancestry. The population showed no evidence of admixture with other populations and low genetic diversity on all measures tested. Based upon our characterisation of this unusual mainland population, we advise against assuming homogeneity of dingoes across the continent. [ABSTRACT FROM AUTHOR]

How new species evolve is one of the most fundamental questions in biology. Population divergence, which may lead to speciation, may be occurring in the Eastern Yellow Robin, a common passerine that lives along the eastern coast of Australia. This species is composed of 2 parapatric lineages that have highly divergent mitochondrial DNA; however, similar levels of divergence have not been observed in the nuclear genome. Here we re-examine the nuclear genomes of these mitolineages to test potential mechanisms underlying the discordance between nuclear and mitochondrial divergence. We find that nuclear admixture occurs in a narrow hybrid zone, although the majority of markers across the genome show evidence of reproductive isolation between populations of opposing mitolineages. There is an 8 MB section of a previously identified putative neo-sex chromosome that is highly diverged between allopatric but not parapatric populations, which may be the result of a chromosomal inversion. The neo-sex chromosomal nature of this region, as well as the geographic patterns in which it exhibits divergence, suggest it is unlikely to be contributing to reproductive isolation through mitonuclear incompatibilities as reported in earlier studies. In addition, there are sex differences in the number of markers that are differentiated between populations of opposite mitolineages, with greater differentiation occurring in females, which are heterozygous, than males. These results suggest that, despite the absence of previously observed assortative mating, mitolineages of Eastern Yellow Robin experience at least some postzygotic isolation from each other, in a pattern consistent with Haldane’s Rule. [ABSTRACT FROM AUTHOR]

Examination of the spawning and maturity traits of coexisting Platycephalus caeruleopunctatus, Platycephalus grandispinis and Platycephalus richardsoni (Pisces: Platycephalidae) in coastal waters of southeastern Australia identified many commonalities. Each species was gonochoristic, reproductively active for a prolonged period each year, displayed asynchronous oocyte development with indeterminate fecundity and thus likely spawned multiple times throughout each spawning season. Males of all three species matured at smaller total lengths and younger ages than females, with skewed sex ratios reflecting divergent growth characteristics between sexes. Reproductive isolation among species is likely maintained through behavioural and morphological factors as well as species‐specific depth‐related separation of reproductively active individuals. General similarities in the reproductive strategies of each species and with other sympatric coastal teleosts suggest similar ecological adaptations to a variable coastal environment. [ABSTRACT FROM AUTHOR]

Species vary extensively in geographic range size and climatic niche breadth. If range limits are primarily determined by climatic factors, species with broad climatic tolerances and those that track geographically widespread climates should have large ranges. However, large ranges might increase the probability of population fragmentation and adaptive divergence, potentially decoupling climatic niche breadth and range size. Conversely, ecological generalism in large-ranged species might lead to higher gene flow across climatic transitions, increasing species' cohesion and thus decreasing genetic isolation by distance (IBD). Focusing on Australia's iconic Ctenotus lizard radiation, we ask whether species range size scales with climatic niche breadth and the degree of population isolation. To this end, we infer independently evolving operational taxonomic units (OTUs), their geographic and climatic ranges, and the strength of IBD within OTUs based on genome-wide loci from 722 individuals spanning 75 taxa. Large-ranged OTUs were common and had broader climatic niches than small-ranged OTUs; thus, large ranges do not appear to simply result from passive tracking of widespread climatic zones. OTUs with larger ranges and broader climatic niches showed relatively weaker IBD, suggesting that large-ranged species might possess intrinsic attributes that facilitate genetic cohesion across large distances and varied climates. By influencing population divergence and persistence, traits that affect species cohesion may play a central role in large-scale patterns of diversification and species richness. [ABSTRACT FROM AUTHOR]

Understanding why and how certain clades emerge as speciation hotspots is a fundamental objective of evolutionary biology. Here we investigate divergences between exotic Onthophagus taurus , a dung beetle introduced into the USA and Australia in the 1970s, as a potential model for the widespread recent speciation events characterizing the genus Onthophagus. To do so, we hybridized O. taurus derived from Eastern US (EUS) and Western Australian (WA) populations, and assessed fitness-relevant trait expression in first- and second-generation hybrids. We found that dams invest more in offspring provisioning when paired with a sire from the same population, and that WA dams crossed with EUS sires produce smaller and lighter F1 hybrids, with an unexpectedly male-biased sex ratio. Furthermore, fewer F2 hybrids with vertically inherited WA cytoplasm and microbiome emerged compared with WA backcrosses with WA cytoplasm/microbiome, suggesting that combinations of nuclear genome, cytoplasm and/or microbiome may contribute to hybrid viability. Lastly, we document a dominance of WA genotypes over body size at the point of inflection between minor and major male morphs, a trait of significance in mate competition, which has diverged remarkably between these populations. We discuss our results in light of the evolutionary ecology of onthophagine beetles and the role of developmental evolution in clade diversification. [ABSTRACT FROM AUTHOR]

• Compatibility of Australian and South African Anaphes nitens populations was tested. • No signs of reproductive isolation were found. • No signs of cytoplasmic incompatibility were found. • Positive or negative effects on fitness were not observed. • No detrimental effect expected on the South African population after release. Introductions of natural enemies in classical biocontrol programs potentially cause genetic bottlenecks which can be detrimental for biocontrol. This can be mitigated by introducing multiple populations of a natural enemy, but thorough pre-release testing is needed to ensure compatibility. In this study compatibility between an established population of Anaphes nitens in South Africa and a newly imported A. nitens population from Australia was tested. Anaphes nitens is an egg parasitoid of Gonipterus sp. n. 2, an important pest in Eucalyptus plantations. South African and Australian A. nitens lineages were compared to two admixed lineages, which were reared from the F0 to the F2 generation. No differences were found in the proportion of replicates producing offspring overall, or female offspring specifically, indicating there was no sexual isolation between the populations. The typical symptoms of cytoplasmic incompatibility in haplodiploids, namely male biased sex ratios, were not observed. The lack of significant differences in fecundity and development time between the lineages suggested that there was no hybrid vigour or outbreeding depression. We conclude that a field release of the imported A. nitens population poses a low risk of disrupting the existing biocontrol program due to reproductive barriers or outbreeding depression. Whether there is a benefit of adding the newly imported Australian A. nitens population to the existing biocontrol system in South Africa needs to be studied further, for example by performing a field release combined with post-release assessments for determining establishment and spread. [ABSTRACT FROM AUTHOR]

Human-mediated dispersal of animals often acts to bring populations that have been separated for substantial periods of evolutionary time (e.g. millions of years) in their native range into contact in their introduced range. Whether these taxa successfully interbreed in the introduced range provides information on the strength of reproductive isolation amongst them. The invasive delicate skink (Lampropholis delicata) has been accidentally introduced to Lord Howe Island from four genetically divergent (>2 million years) regions of the species' native range in eastern Australia. We used mitochondrial DNA and microsatellite data to investigate whether the individuals from four of the native-range source regions are interbreeding on Lord Howe Island. Our analyses indicate that intraspecific hybridisation among individuals from all four native-range source regions is occurring. Although there is little evidence for hybrids in the northern end of Lord Howe Island (proportion of hybrids: 0–0.02; n = 31), there is a high proportion of hybrids in the central (0.33–0.69; n = 59) and southern regions (0.38–0.75; n = 8) of the island. Given the strong evidence for interbreeding among all four native-range source regions examined, and the relatively minor morphological, life-history and phenotypic variation among them, we suggest that the delicate skink should continue to be treated as a single, widespread, but variable species. Human-assisted dispersal can act to bring populations that have been separated for millions of years into secondary contact in their introduced range. We demonstrate that interbreeding is occurring amongst individuals from the four genetically divergent (>2 million years) native-range lineages of the delicate skink (Lampropholis delicata) that are present on Lord Howe Island. Our findings indicate that, despite substantial genetic structure across its native range, the delicate skink is a single, widespread, but variable species. Photograph by Sarah Simmonds. [ABSTRACT FROM AUTHOR]

Shifts in flowering time have the potential to act as strong prezygotic reproductive barriers in plants. We investigate the role of flowering time divergence in two species of mountain rose (Metrosideros) endemic to Lord Howe Island, Australia, a minute and isolated island in the Tasman Sea. Metrosideros nervulosa and M. sclerocarpa are sister species and have divergent ecological niches on the island but grow sympatrically for much of their range, and likely speciated in situ on the island. We used flowering time and population genomic analyses of population structure and selection, to investigate their evolution, with a particular focus on the role of flowering time in their speciation. Population structure analyses showed the species are highly differentiated and appear to be in the very late stages of speciation. We found flowering times of the species to be significantly displaced, with M. sclerocarpa flowering 53 days later than M. nervulosa. Furthermore, the analyses of selection showed that flowering time genes are under selection between the species. Thus, prezygotic reproductive isolation is mediated by flowering time shifts in the species, and likely evolved under selection, to drive the completion of speciation within a small geographical area. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'. [ABSTRACT FROM AUTHOR]

Animals use mating traits to compete for, attract, and choose mates. Because mating traits influence mate choice, the divergence of mating traits between populations can result in reproductive isolation. This can occur without associated morphological divergence, producing reproductively isolated cryptic species that are visually indistinguishable. Thus, identifying the mating traits in morphologically conservative groups is key to resolving diversity and speciation processes. Lizards contain many such groups, with phylogeographic studies often revealing highly divergent but morphologically cryptic lineages within species. Considering that cryptic lizard species can be sympatric but morphologically indistinguishable, we hypothesize that candidate species will exhibit divergent pheromones and that pheromones will have typically diverged more than morphology. To test this, we used gas chromatography to characterize pheromones (epidermal pore secretions) from 10 genetically divergent lineages of the Bynoe's gecko (Heteronotia binoei) species complex in northern Australia. Multivariate analyses of pheromone blends and morphology indicate that pheromones are lineage specific and have diverged relatively more than morphology. Such specificity suggests that pheromones influence behavioral isolation in this morphologically conservative lizard radiation. These results suggest that pheromone data may unlock the tremendous cryptic diversity currently being uncovered in many lizard groups. [ABSTRACT FROM AUTHOR]

Historically fragmented and specialized habitats such as granite outcrops are understudied globally unique hot spots of plant evolution. In contrast to predictions based on mainstream population genetic theory, some granite outcrop plants appear to have persisted as very small populations despite prolonged geographic and genetic isolation. Eucalyptus caesia Benth. is a long‐lived lignotuberous tree endemic with a naturally fragmented distribution on granite outcrops in south‐western Australia. To quantify population to landscape‐level genetic structure, we employed microsatellite genotyping at 14 loci of all plants in 18 stands of E. caesia. Sampled stands were characterized by low levels of genetic diversity, small absolute population sizes, localized clonality and strong fine‐scale genetic subdivision. There was no significant relationship between population size and levels of heterozygosity. At the landscape scale, high levels of population genetic differentiation were most pronounced among representatives of the two subspecies in E. caesia as originally circumscribed. Past genetic interconnection was evident between some geographic neighbours separated by up to 20 km. Paradoxically, other pairs of neighbouring stands as little as 7 km apart were genetically distinct. There was no consistent pattern of isolation by distance across the 280 km range of E. caesia. Low levels of gene flow, together with strong drift within stands, provide some explanation of the patterns of genetic differentiation we observed. Individual genet longevity via the ability to repeatedly resprout and expand from a lignotuber may enhance the persistence of some woody perennial endemic plants despite small population size, minimal genetic interconnection and low heterozygosity. [ABSTRACT FROM AUTHOR]

Specialized mycorrhizal interactions have the potential to limit the geographical range of plant species and contribute to reproductive isolation. We investigated these predictions in Caladenia (Orchidaceae) from south-western Australia, a group known to have specialized mycorrhizal associations with the genus Sebacina s.l. Sequencing of fungal isolates from 47 of the 136 species of Western Australian Caladenia was undertaken to resolve the geographical range and habitat preferences of mycorrhizal fungal operational taxonomic units (OTUs) and their host breadth in Caladenia. Eight different fungal OTUs were used by Caladenia, with the more frequently detected OTUs occurring in a wide range of habitats and geographical regions. Given the comparatively narrow geographical ranges of most Western Australian Caladenia taxa, this suggests that the geographical ranges of fungal OTUs are unlikely to limit the geographical range of Caladenia spp. Extensive sharing of fungal OTUs between closely related orchid species was detected, suggesting that in the main there is little potential for mycorrhizal fungi to contribute to reproductive isolation between Caladenia spp. Our data mostly support previous work suggesting high mycorrhizal specificity in Caladenia, but this may not be the case in all subgenera, highlighting that Caladenia may offer powerful opportunities for investigating the evolution of specialized mycorrhizal associations. [ABSTRACT FROM AUTHOR]

Regular bird surveys at one site in the marine plain grasslands in the Rockhampton district of the Central Queensland coast, between 2005 and 2011, have recorded the presence of Brown Songlarks Cincloramphus cruralis throughout the year, indicating a sedentary population in this region. This sedentary pattern is at variance with the seasonally dispersive pattern typical for eastern Australia in which Brown Songlarks undergo a regular anticlockwise cycle from south-eastern Australia in summer, up the eastern coast and then spreading across central temperate and subtropical Australia in the winter, before returning to the south-eastern corner. The discovery of a nest with eggs in December 2010 confirmed local breeding by this subpopulation. The relative isolation, local breeding and sedentary nature of this subpopulation raises the possibility that it may be genetically separated from southern and inland Songlarks. [ABSTRACT FROM AUTHOR]

Precaudal vertebral counts were used to distinguish between 237 morphologically similar Carcharhinus limbatus and Carcharhinus tilstoni and were congruent with differences in reproductive ecology between the species. In addition to differing lengths at maturity and adult body size, the two species had asynchronous parturition, were born at different sizes and the relative frequencies of neonates differed in two coastal nursery areas. Despite evidence that hybridization can occur, these differences suggest the species are largely reproductively isolated. [ABSTRACT FROM AUTHOR]

Parmelioid lichens form the largest monophyletic group within the Parmeliaceae, a family distributed worldwide. The genus Parmelina was described by Hale (1976a) accommodating species from both hemispheres. We have employed parsimony, Bayesian and maximum likelihood analyses of a combined data set of nu ITS, LSU and mt SSU rDNA sequences to (1) test the monophyly of Parmelina and (2) to elucidate the generic status and phylogenetic position of the Australasian species. Twenty-one new sequences were generated in this study. Our results provide evidence that Parmelina is polyphyletic and the species fall into two major well-supported groups (Groups I and II). The Australasian species of Parmelina and two species of Canoparmelia (C. pruinata and C. macrospora) form Group I, which is nested within the parmotremoid genera of Parmeliaceae, Parmelina species from the northern hemisphere including those from western North America and the Mediterranean basin form a monophyletic group (Group II), which is sister to the East Asian temperate genus Myelochroa. Morphological and chemical features were reevaluated considering this observed phylogeny. Some morphological features like lobe morphology, several traits in the excipulum and geography are useful in characterizing the monophyletic lineage of the Australasian Parmelina/Canoparmelina species. This lineage is described as the new genus Austroparmelina. Thirteen new combinations in the new genus are proposed. [ABSTRACT FROM AUTHOR]

The heath mouse (Pseudomys shortridgei) is a locally rare species; it was considered extinct in Western Australia until its rediscovery 20 years ago. It is not often detected in faunal surveys and is confined to two ecologically distinct habitats on either side of the Australian continent. An important and immediate conservation question has been to determine the genetic diversity within each of its current habitats and to determine the differences between the geographically separate populations. Measures of genetic differentiation amongst P. shortridgeipopulations in their eastern (Victoria) and western (Western Australia) distribution were estimated using nuclear (microsatellite loci) and partial sequence of mitochondrial DNA (427bp Cytochrome bgene and 637bp of the D-loop). Both markers identified differences between the east- and west-coast populations. MtDNA data showed significant divergence between populations with monophyly within them, and nuclear loci investigated also showed two clear genetic clusters based on Bayesian inference. As a result of these findings, we suggest that the heath mouse comprises two highly divergent (but genetically diverse) lineages and the aridity of the Nullarbor Plain has clearly been a barrier for dispersal since the early Pleistocene (~1.43million years ago). The populations either side of the Nullarbor Plain are genetically differentiated and should be defined as separate Evolutionary Significant Units (ESUs). [ABSTRACT FROM AUTHOR]

Although the south-western Australian region is recognised as a global biodiversity hotspot, there are still significant gaps in our understanding of the biodiversity of this region. We present a phylogenetic study of the heath dragons (Rankinia adelaidensisand R. parviceps) from this region, incorporating a 1612-bp section of mtDNA and two nuclear introns, Gapdh (~244bp) and Enol (~330bp). In addition, we present a generic-level analysis of three gene regions (mtDNA, Gapdh, BDNF), which provides clear evidence that Rankinia adelaidensisand R. parvicepsare not closely related to Rankinia diemensisfrom eastern Australia. Instead, the heath dragons are strongly supported as forming a clade with the genus Ctenophorus. In addition, we find that there are significant levels of haplotype divergence between currently recognised subspecies of the heath dragons (R. a. adelaidensis, R. a. chapmani, R. p. parviceps, R. p. butleri). We suggest that the genetic divergences between subspecies result from geographic isolation in allopatry owing to habitat preferences, followed by drift and/or selection. On the basis of these deep divergences and consistent morphological differences between subspecies, we recommend elevating all taxa to full species, and provide a taxonomic revision of the genera Rankiniaand Ctenophorus. [ABSTRACT FROM AUTHOR]

Intermittently open/closed coastal lakes and lagoons are susceptible to contamination and nutrient-enrichment. Although many of them are considered to be degraded, our understanding of their ecology and the effects of anthropogenic activity is limited. This study of coastal lakes in New South Wales compared the density and distribution of macrobenthos in localities that differed in their degree of isolation from the sea, that is, open versus closed lakes and mouths versus inner reaches. Lakes kept open artificially (to improve water quality and reduce flooding), were also compared with naturally open or closed lakes. Densities of macrobenthos were usually greater in the mouths of open than of closed lakes, but the opposite was true in inner reaches. While isolated localities differed more between lakes than did mouths, small-scale variability was greater in the latter. Spatial patterns were less temporally consistent in inner reaches than in mouths. Differences in densities and spatial variability between mouths and inner reaches were influenced primarily by whether a lake was open or closed and secondarily by manipulation of the mouth. While, for example, densities in open manipulated systems were usually greater in the mouths, but smaller in the inner reaches, the effect of manipulation was less obvious in closed lakes. Differences in density between types of lakes were not clearly related to physical factors although, within lakes, benthos generally correlated negatively with salinity and positively with median particle-size, silt and organic content. The effects of factors that modify the degree of isolation of coastal lakes are discussed and it is concluded that current levels of isolation do not appear to affect macrobenthos adversely. Nevertheless, increased isolation, which is likely as a result of climatic change, may well do so, particularly in lakes already stressed by human impacts. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of island isolation on songs of three species of Australian songbirds. The characteristics of songs recorded from mainland locations were compared with those recorded on Rottnest Island off the coast of Western Australia. In all three species, the characteristics of the island song patterns differed from those on the mainland. Each species exhibited a different kind of divergence on the island, including (1) differences in the structure of individual notes and syllables constituting songs; (2) differences in temporal patterns of song delivery; and (3) differences in the order of notes within songs. In two species, the island songs were less complex than mainland songs and this may be the consequence of a founder effect. In the third species, island songs were more elaborate and diverse, and this may be the consequence of sexual selection, although other explanations are plausible. For several of these populations, quantitative comparisons were made between samples collected 6–7 years apart. In two species, new recordings made in 2004 were compared with those made in 1998 and, in one species, recordings made in 1991 were compared with those made in 1998. For the nine comparisons available, similarity scores across years did not change significantly; thus, there was no evidence of systematic divergence with time. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 331–342. [ABSTRACT FROM AUTHOR]

Four geographic strains of B. calyciflorus are investigated regarding their genetic similarity and ability to cross-mate. DNA sequence analysis of the mitochondrial cox1 gene (694 bp) and the nuclear ribosomal ITS region (735 bp) showed that the Florida and Georgia strains were very similar to each other (0.3% sequence divergence for the 1429 bp) and different from the Texas and Australia strains (~7% and 9% sequence divergence for the 1429 bp, respectively). Consistent with this genetic relatedness, cross-copulation occurred only between the Florida and Georgia strains. Thus, B. calyciflorus is a complex of cryptic species. While the Florida, Texas and Australia strains were reproductively isolated from one another, most combinations of cross-strain mating tests showed intense and prolonged male circling behavior following male–female encounters. This suggests that precopulatory male circling and copulation are two separate behaviors that may be controlled by different female chemicals and male coronal receptors. In some cross-strain mating tests, females regularly retracted their corona when circled by a male, indicating that they can recognize ‘foreign’ males and actively interfere with copulation. [ABSTRACT FROM AUTHOR]

1. We tested for effects of habitat fragmentation in a controlled, replicated, field experiment, in south-eastern Australia. Our experimental subjects were eight carabid beetle species, and the carabid assemblage (45 species). Monitoring was by pitfall trapping in forest remnants and in adjacent continuous-forest controls. Remnants were of three sizes (0·25, 0·875, 3·062 ha.). Monitoring commenced 2 years prior to habitat fragmentation. Here we present results for 6 years after habitat fragmentation (4 years for species richness). 2. We tested four hypotheses. Hypothesis one: habitat fragmentation reduces species richness in the remaining remnants. Carabid species richness was not different in habitat remnants compared to continuous forest, neither was carabid richness different for remnants of different sizes, or at monitoring sites close to remnant edges compared to sites in remnant interiors. 3. Hypothesis two: populations decline as a result of habitat fragmentation. Two species of eight were completely isolated on remnants and both declined in abundance on remnants compared to control plots in continuous forest. The other six species responded in various ways, which included relative increases and decreases in abundance and no change, but as they were not completely isolated on remnants, their responses could not be explained by isolation. 4. Hypothesis three: remaining subpopulations decline further on smaller habitat remnants than on larger remnants. Three species responded to remnant size; one was most abundant in small remnants, the second was most abundant in large remnants, and the third was equally abundant in small and large remnants and less abundant in medium-sized remnants. 5. Hypothesis four: populations near to remnant edges decline further than populations in remnant interiors. Two species were more likely to occur in remnant interiors than at edges, whereas three species were equally likely to occur in remnant interiors and at edges. 6. The effects of habitat fragmentation may be the consequence of: (i) isolation; and (ii) habitat modification. In this study, we were able to consider effects of isolation for two carabid species. We tested only one aspect of the habitat modification hypothesis, edge effects. We discuss the possibility that other aspects of habitat modification in remnants may explain some of our results and suggest that this is where future research be directed. [ABSTRACT FROM AUTHOR]