Genetic evidence for the origins of range disjunctions in the Australian dry sclerophyll plant Hardenbergia violacea

Aim The distribution of genetic variation in the Australian dry sclerophyll plant Hardenbergia violacea (Fabaceae) is examined in the context of Pleistocene climate change in order to identify likely refugia. Particular consideration is given to the origin of range disjunctions in South Australia and Tasmania, and to determining whether the Tasmanian population is indigenous or recently introduced from mainland Australia. Location Southeastern Australian mainland and Tasmania. Methods A combination of chloroplast polymerase chain reaction–restriction fragment length polymorphism and genomic amplified fragment length polymorphism (AFLP) marker systems was used to examine the genetic structure of 292 individuals from 13 populations across the range of H. violacea in southeastern Australia. Results Hardenbergia violacea populations in Tasmania and southern Victoria were characterized by low, almost monotypic chloroplast diversity. New South Wales showed higher haplotype diversity and haplotype sharing among widely distributed populations. Principal coordinates analysis (PCoA) of the AFLP data found a strong latitudinal cline in AFLP variation from northern New South Wales south to Tasmania. The Tasmanian population formed an isolated and somewhat disjunct genetic cluster at one end of this cline. However, the South Australian population was an exception to the clinal variation shown by all other populations, forming a highly disjunct cluster in the PCoA. Within‐population genetic diversity was low in both disjunct populations. Main conclusions The genetic evidence indicates that the Tasmanian population is likely to be indigenous and probably the product of vicariance, which was followed by range contraction at the Last Glacial Maximum or an earlier glacial event. The deep phylogenetic disjunction in South Australia is evidence of a much earlier separation on mainland Australia. The chloroplast structure indicates that, during the Pleistocene, H. violacea underwent broad‐scale recolonization in southern Victoria and Tasmania, possibly from a large continental refugium in eastern New South Wales. We conclude that H. violacea, and presumably the sclerophyll communities in which it occurs, have undergone multiple range contractions to large continental refugia during different Pleistocene glaciations in southeastern Australia.     

Gymnodinium catenatum Graham isolated from the Portuguese coast: Toxin content and genetic characterization

The bloom forming marine dinoflagellate Gymnodinium catenatum Graham has been linked to paralytic shellfish poisoning (PSP) outbreaks in humans. Along the Portuguese coast (NE Atlantic), G. catenatum shows a complex bloom pattern, raising questions about the origin and affinities of each bloom population. In this work, the variability within six cultured strains of G. catenatum isolated from Portuguese coastal waters (S coast, W coast and NW coast), between 1999 and 2011, was investigated. The strains were analyzed for toxin profiling and intra-specific genetic diversity. Regarding the toxin profile, differences recorded between strains could not be assigned to the time of isolation or geographical origin. The parameter that most influenced the toxin profile was the life-cycle stage that originated the culture: vegetative cell versus hypnozygote (resting cyst). At the genetic level, all strains showed similar sequences for the D1–D2 region of the large subunit (LSU) of the nuclear ribosomal DNA (rDNA) and shared complete identity with strains from Spain, Algeria, China and Australia. Conversely, we did not find a total identity match for the ITS-5.8S nuclear rDNA fragment. After sequence analysis, two guanine/adenine (R) single nucleotide polymorphisms (SNP 1 and 2) were detected for all strains, in the ITS1 region. This species has been reported to present very conservative LSU and ITS-5.8S rDNA regions, though with few SNP, including SNP1 of this study, already attributed to strains from certain locations. The SNP here described characterize G. catenatum populations from Portuguese waters and may represent valuable genetic markers for studies on the phylogeography of this species.     

Global toxicology,ecophysiology and population relationships of the chainforming PST dinoflagellate Gymnodinium catenatum

Increasing scientific awareness since the 1980s of the chain-forming dinoflagellate Gymnodinium catenatum has led to this species being reported with increased frequency in a globally increasing number of countries (23 at present). G. catenatum exhibits little molecular genetic variation in rDNA over its global range, in contrast to RAPD fingerprinting which points to high genetic variation within regional populations even between estuaries 50 km apart. All Australian and New Zealand strains possess a thymine nucleotide (T-gene) near the start of the 5.8S rRNA whereas all other global populations examined to date possess cytosine-nucleotide (C-gene), except for southern Japan which harbours both C-gene and T-gene strains. Together with cyst and plankton evidence this strongly suggests that both Australian and New Zealand populations have derived from southern Japan. Global dinoflagellate populations and cultures exhibit an extraordinary variation in PST profiles (STX and 21 analogues), but consistent regional patterns are evident with regard to the production of C1,2; C3,4; B1,2; and neoSTX analogues. PST profiles of cyst-derived cultures are deemed unrepresentative. Distinct ecophysiological differences exist between tropical (21–32 °C) and warm-temperate ecotypes (12–18 °C), but these appear unrelated to ITS genotypes and PST toxin phenotypes. On current evidence, cyst germination appears to play a minimal role in the bloom dynamics of this species, while seasonal and inter-annual bloom variations result from the physical constraints (temperature and light) on the growth of the dinoflagellates in the water column. G. catenatum exhibits a capacity to utilize many forms of nitrogen. Its chain formation and strong motility allow it to undergo retrieval migrations to exploit light and nutrient resource gradients in both stratified and mixed environments. Subtle strain-level variations in micronutrient (Se, humics) requirements and interaction with associated bacterial flora may provide a partial explanation for the contrasting inshore (Tasmanian), and offshore (Spain, Mexico) bloom patterns by the same species in different geographic regions.     

High levels of genetic divergence between Tasmanian and Victorian platypuses, Ornithorhynchus anatinus, as revealed by microsatellite loci

The platypus, Ornithorhynchus anatinus is a unique, iconic mammal endemic to Australia. Despite being listed as ‘common’ throughout its range, platypus abundance is poorly understood. Dependence on aquatic habitats in Australia renders this species potentially vulnerable to a variety of processes including drought, climate change and habitat loss. To assist with understanding population processes, 180 individuals from Tasmania and Victoria were characterised across thirteen microsatellite loci. Large genetic differences were evident between Tasmanian and Victorian O. anatinus. Within Tasmania, high levels of allelic diversity were detected with genetic differentiation identified among some populations. Similarly, allelic diversity was high within Victorian platypuses, along with significant genetic differentiation among populations. The large genetic differences found between Tasmanian and mainland platypuses indicate long-term isolation and it is likely that the lack of past/present catchment connectedness contributes to differentiation found between populations within these regions. Understanding patterns of genetic differentiation within and between catchments will help guide future conservation management decisions for platypus.     

Intraspecific variation in the selenium requirement of different geographic strains of the toxic dinoflagellate Gymnodinium catenatum

The requirement for selenium (IV) was assessed in five strainsof the toxic dinoflagellate Gymnodinium catenatum Graham, representingthree populations from Tasmania (Australia), as well as oneeach from Japan and Spain. Strains were grown in nutrient-enrichedsea water medium with 10^–9 M selenium added as selenite(H₂SeO₃), or with no added selenium, and monitored for growthand cell yield. Strains exhibited different selenium (Se) requirements,as evidenced by (i) a decrease in exponential growth rate (10–20%)and cell yield (up to 80%) (Japanese strain); (ii) a decreasein cell yield only (Tasmania Derwent Estuary 1987, TasmaniaHuon Estuary and Spanish strains); and (iii) no decrease ingrowth or cell yield (Tasmania Derwent Estuary 1993 strain).Variation in the response to Se deficiency was greatest betweenthe two strains isolated from the Derwent Estuary, Tasmania,in different years (1987 and 1993) and less between Tasmanianstrains from different localities (Huon and Derwent Estuariesare 50 km apart) or between Tasmanian and Japanese or Spanishstrains. Strain variability in micro-nutrient responses suchas described here may provide a partial explanation for differentbloom patterns exhibited by the same dinoflagellate taxon underapparently similar environmental conditions.     

When is a native species invasive? Incursion of a novel predatory marsupial detected using molecular and historical data

Aim

Range expansions facilitated by humans or in response to local biotic or abiotic stressors provide the opportunity for species to occupy novel environments. Classifying the status of newly expanded populations can be difficult, particularly when the timing and nature of the range expansion are unclear. Should native species in new habitats be considered invasive pests or actively conserved? Here, we present an analytical framework applied to an Australian marsupial, the sugar glider (Petaurus breviceps), a species that preys upon on an endangered parrot in Tasmania, and whose provenance was uncertain.

Location

Tasmania, Australia.

Methods

We conducted an extensive search of historical records for sugar glider occurrences in Tasmania. Source material included museum collection data, early European expedition logs, community observation records, and peer‐reviewed and grey literature. To determine the provenance of the Tasmanian population, we sequenced two mitochondrial genes and one nuclear gene in Tasmanian animals (n = 27) and in individuals across the species' native range. We then estimated divergence times between Tasmania and southern Australian populations using phylogenetic and Bayesian analyses.

Results

We found no historical evidence of sugar gliders occurring in Tasmania prior to 1835. All Tasmanian individuals (n = 27) were genetically identical at the three genes surveyed here with those individuals being 0.125% divergent from individuals from a population in Victoria. Bayesian analysis of divergence between Tasmanian individuals and southern Australian individuals suggested a recent introduction of sugar gliders into Tasmania from southern Australia.

Main conclusions

Molecular and historical data demonstrate that Tasmanian sugar gliders are a recent, post‐European, anthropogenic introduction from mainland Victoria. This result has implications for the management of the species in relation to their impact on an endangered parrot. The analytical framework outlined here can assist environmental managers with the complex task of assessing the status of recently expanded or introduced native species.

     

Hierarchical genetic structure of the introduced wasp Vespula germanica in Australia

The wasp Vespula germanica is a highly successful invasive pest. This study examined the population genetic structure of V. germanica in its introduced range in Australia. We sampled 1320 workers and 376 males from 141 nests obtained from three widely separated geographical areas on the Australian mainland and one on the island of Tasmania. The genotypes of all wasps were assayed at three polymorphic DNA microsatellite markers. Our analyses uncovered significant allelic differentiation among all four V. germanica populations. Pairwise estimates of genetic divergence between populations agreed with the results of a model-based clustering algorithm which indicated that the Tasmanian population was particularly distinct from the other populations. Within-population analyses revealed that genetic similarity declined with spatial distance, indicating that wasps from nests separated by more than approximately 25 km belonged to separate mating pools. We suggest that the observed genetic patterns resulted from frequent bottlenecks experienced by the V. germanica populations during their colonization of Australia.     

A phylogeographic analysis of southern and eastern populations of the Australian magpie: evidence for selection in maintenance of the distribution of two plumage morphs

The Australian magpie ( Gymnorhina tibicen ) is polymorphic for back colour with three distinct morphs recognized: the black-backed form (BB) which occurs in northern and north-eastern Australia; the white-backed form (WB) which occurs in south-eastern Australia and Tasmania and the Western form which occurs in the far south-west corner of the continent. Male and female WBs and BBs are both monomorphic for back colour while Westerns are sexually dimorphic, with males white-backed and females black-backed. In the south-east the WB and BB distributions overlap with individuals of intermediate phenotype interspersed with pure WB and BB phenotypes. This study used mtDNA control-region sequences to test the predictions of two alternative hypotheses to explain the distribution of WB and BB populations in eastern Australia and Tasmania. Our data support the hypothesis that the variation has evolved in situ, as no population genetic structuring was evident in eastern Australia related to back colour and Tasmanian WBs were no more closely related to mainland WBs than to mainland BBs (primary contact hypothesis). Back colour patterns may be maintained by different forms of natural selection favouring BB genes in the north-east and WB genes in the south-east.     

High microsatellite diversity and differential structuring among populations of the introduced common brushtail possum, Trichosurus vulpecula, in New Zealand

An understanding of genetic variation and structure of pest populations has the potential to improve the efficiency of measures to control them. Genetic analysis was undertaken at five microsatellite loci in four native Australian and 14 introduced New Zealand populations of the common brushtail possum Trichosurus vulpecula in order to document these parameters. Genetic variation in New Zealand populations, and phylogenetic relationships among Australian and New Zealand populations, were largely predicted by the recorded introduction history. Populations on the two main islands of New Zealand had only slightly lower genetic diversity than did Australian populations, except that allelic richness on the South Is. was significantly lower. Diversity was higher in North Is. than in South Is. populations (although not significantly so) and mainland New Zealand populations as a group were significantly more diverse than offshore islands that represented secondary population size bottlenecks. In phylogenetic analyses South Is. and offshore island populations grouped with Tasmania, while North Is. populations grouped either with mainland Australia or were intermediate between the two Australian sources. This scheme was supported by admixture coefficients showing that North and South Is./offshore island populations were largely mainland Australian and Tasmanian in origin, respectively. Population structure differed markedly between the North and South Islands: populations were typically more genetically differentiated on the former than the latter, which also showed significant isolation-by-distance. Substantial linkage disequilibrium in most sampled New Zealand but no Australian population between microsatellite loci Tv16 and Tv27 suggests they may be physically linked.     

Differences in egg parasitism of Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae) by Enoggera nassaui Girault (Hymenoptera: Pteromalidae) in relation to host and parasitoid origin

Abstract The first instances of egg parasitism of Chrysophtharta agricola , a pest of eucalypt plantations, are recorded. Enoggera nassaui was found parasitising C. agricola egg batches in Tasmania, the Australian Capital Territory (ACT), New South Wales and Victoria: this is the first record of this parasitoid species from Victoria. One instance of Neopolycystus sp. parasitising C. agricola eggs in Victoria was also recorded. Parasitism of egg batches by E. nassaui ranged from 0 to 55% between five geographical populations collected in mainland Australia ( n  = 45), and from 0 to 2% between two populations collected in Tasmania ( n  = 300). For mainland sites at which parasitism was recorded, parasitism rates within sites differed significantly from either population in Tasmania. Reciprocal exposure experiments using one Tasmanian (Florentine Valley) and one parasitised mainland (Picadilly Circus, ACT) population were conducted in the laboratory to examine whether these different parasitism rates were attributable to egg or parasitoid origin. Parasitoids from the ACT parasitised C. agricola eggs of both origins more successfully than parasitoids from Tasmania, with up to 65% wasp emergence compared with 33% from Tasmania. Parasitoid origin significantly affected the number of wasps that emerged from exposed batches, but not the total loss from parasitism.     

Group-specific component subtypes in the population of Tasmania, Australia

Plasma specimens from 2,010 blood donors resident throughout the island State of Tasmania, Australia, were examined for group-specific component (GC) sub-types using polyacrylamide gel iso-electric focusing. Subdivision of the island into 8 geographic regions revealed no significant heterogeneity. Comparison of GC allele frequencies with those reported in mainland Australian populations indicated that Tasmanian values lie well within the ranges previously reported.     

THE BIRDS OF TASMANIA: ECOLOGY AND EVOLUTION

SUMMARY Tasmania, about the size of Ireland, separated from the Australian mainland by 140 miles of sea, and isolated for about the last 12,000 years, has 104 species of native breeding land-birds, with the addition of ten introduced species. The environment is described; in particular the vegetation is classified into nine natural types and three produced by European man; and the distribution of the bird species among these is defined and discussed. The other vertebrates are briefly considered. No extinction is definitely known to have taken place as a result of European settlement except of the Tasmanian Emu (and of course Tasmanian Man). An attempt is made to reconstruct the Late Pleistocene history of Tasmania and its vegetation, with special reference to the Last Glaciation, when the island would have been joined to the mainland. When the avifauna is divided into categories, water-birds, raptors, etc., it is found to have much the same proportional composition as the Australian mainland avifaunas with which it is compared, though it consists of many fewer species. The vegetation types of the colder and wetter areas of Tasmania house far fewer species of birds than the drier and warmer habitats. The 104 breeding species include 14 endemics, which are considered in detail, and 27 endemic subspecies. As shown by comparison with other islands, the total proportionate endemism is extraordinarily high for a recent continental island (though it is actually lower than that in the remote ecological island formed by the sclerophyll of southwestern Western Australia). A contributory cause may be that Tasmania is not regularly visited by land-birds from the continent (though at least one-fifth of the Tasmanian species are partial or total migrants in winter). The most noteworthy endemics are two monotypic genera, Lathamus and Acanthornis, and the Native Hen Tribonyx mortierii, which has become flightless apparently in the face of a formidable array of local predators. Considerations of climate and habitat suggest that at least half the avifauna, including 19 of the endemic subspecies and six of the members of superspecies, arrived in Tasmania some time after the amelioration of the Last Glaciation began, some 18,000 years ago. Geographical considerations suggest that four of those six members of superspecies existed in their present form when the land-bridge to the mainland was cut, 12,000 years ago. Certain habitats, widespread over southeastern Australia during the glaciation, are now virtually confined to Tasmania where they form the stronghold of certain species, such as the Pink Robin Petroica rodinogaster, which occur only as relicts on the mainland. The endemic Scrub Tit Acanthornis magnus is practically confined to such habitats, where its ecology suggests it would have been well adapted to glacial conditions. Among the local endemics there is a strong tendency for colouration to be more saturated than on the continent of Australia (Gloger's rule) but there is less consistency in tendency to greater size (Bergmann's rule). A noteworthy proportion of the Tasmanian species have duller plumage than their mainland relatives, usually with an assimilation to female or juvenile plumage—unexpected in an island as big as Tasmania with so considerable an avifauna.     

Phylogeography of the world's tallest angiosperm, Eucalyptus regnans: evidence for multiple isolated Quaternary refugia

Aim There is a need for more Southern Hemisphere phylogeography studies, particularly in Australia, where, unlike much of Europe and North America, ice sheet cover was not extensive during the Last Glacial Maximum (LGM). This study examines the phylogeography of the south‐east Australian montane tree species Eucalyptus regnans. The work aimed to identify any major evolutionary divergences or disjunctions across the species’ range and to examine genetic signatures of past range contraction and expansion events. Location South‐eastern mainland Australia and the large island of Tasmania. Methods We determined the chloroplast DNA haplotypes of 410 E. regnans individuals (41 locations) based on five chloroplast microsatellites. Genetic structure was examined using analysis of molecular variance (AMOVA), and a statistical parsimony tree was constructed showing the number of nucleotide differences between haplotypes. Geographic structure in population genetic diversity was examined with the calculation of diversity parameters for the mainland and Tasmania, and for 10 regions. Regional analysis was conducted to test hypotheses that some areas within the species’ current distribution were refugia during the LGM and that other areas have been recolonized by E. regnans since the LGM. Results Among the 410 E. regnans individuals analysed, 31 haplotypes were identified. The statistical parsimony tree shows that haplotypes divided into two distinct groups corresponding to mainland Australia and Tasmania. The distribution of haplotypes across the range of E. regnans shows strong geographic patterns, with many populations and even certain regions in which a particular haplotype is fixed. Many locations had unique haplotypes, particularly those in East Gippsland in south‐eastern mainland Australia, north‐eastern Tasmania and south‐eastern Tasmania. Higher haplotype diversity was found in putative refugia, and lower haplotype diversity in areas likely to have been recolonized since the LGM. Main conclusions The data are consistent with the long‐term persistence of E. regnans in many regions and the recent recolonization of other regions, such as the Central Highlands of south‐eastern mainland Australia. This suggests that, in spite of the narrow ecological tolerances of the species and the harsh environmental conditions during the LGM, E. regnans was able to persist locally or contracted to many near‐coastal refugia, maintaining a diverse genetic structure.     

The invasion biology of the invasive earwig, <Emphasis Type="Italic">Forficula auricularia</Emphasis> in Australasian ecosystems

The European earwig, Forficula auricularia, is a cosmopolitan insect endemic to Europe, West Asia and North Africa, which has invaded many temperate regions of the world including Australia and New Zealand. F. auricularia has been shown to be a complex of morphologically identical, reproductively isolated lineages that possess two distinct clades of mitochondrial DNA. Entomological collection data, historical literature and further field collections were used to develop a greater understanding of Australian F. auricularia’s invasion biology and its current distribution. Genetic analysis of F. auricularia collected from Australia and New Zealand using two mitochondrial genes (COI and a fragment overlapping parts of the COI -COII genes) was also undertaken. To identify the possible source populations of the Australasian invasion these sequences were compared to those from 16 locations within Britain and continental Europe. All Australasian populations were shown to be of the clade B lineage. Tasmanian and New Zealand populations consist of a single subclade comprised of only 4 and 1 haplotypes respectively. The Australian mainland populations also contained a second subclade consisting of up to 11 haplotypes indicating that multiple introductions possibly occurred on the Australian mainland. Comparison of mitochondrial genomes from Australasian and European populations showed the Australian mainland subclade to be most closely related to Portuguese haplotypes, and the Tasmanian and New Zealand clade closely related to those in Brittany, France. No European haplotypes perfectly matched the Australasian sequences. Therefore, the original source populations are still to be identified with harbours on the Iberian Peninsula’s western coast and those on the English Channel likely candidate areas.     

Growth and genotypes of Echinococcus granulosus found in cattle imported from Australia and fattened in Japan

At the abattoir on study in Miyazaki, Japan, 9537 imported cattle from Australia in average were slaughtered annually in the last 5 years (2006 to 2010) and hydatid cysts were constantly detected in about 1.8% of the cattle. In order to assess the risk of Echinococcus granulosus delivered to Japan by imported cattle, 250 cysts found in 103 cattle at the abattoir were examined for their biological characteristics and genotypes. The cattle slaughtered were imported from Australia at an age of 10-12 months old and fattened for 17-18 months in Japan. The cysts showed their size ranging from 4 to 108 mm and were mainly found in the lung. Mature protoscoleces were detected in the three largest cysts, all were of the G1 genotype. Most of the other cysts contained clear cyst fluid and had thin laminated layer with no protoscoleces. The finding implies a potential risk of E. granulosus being established in Japan, thus strict and proper meat inspection and consequent offal condemnation are requisite at abattoirs that deal with imported cattle. Genotyping based on partial fragments of mitochondrial cox1, rrnS and nad1 genes were performed on the 66 cysts, showing that most of the cysts were G1 genotype (common sheep strain). However, two and four cysts were considered as G2 (Tasmanian sheep strain) and G3 (buffalo strain) genotypes, respectively. Since it has been widely recognized that G1 is the only genotype distributing in mainland Australia and that G2 genotype has been eradicated from Tasmania, the finding of those genotypes from Australian cattle indicated that certain genotypes other than G1 genotype are distributing in mainland Australia.     

Taxonomy of Australian freshwater algae. I. The genus Micrasterias in South-Eastern Australia

A preliminary survey has been made of the desmid genus Micrasterias in Tasmania, as the first part of an intended series of detailed investigations of Tasmanian freshwater algae. For comparative purposes, samples from the south-eastern states of mainland Australia are included. Micrasterias hardyi West, apparently an Australian endemic, is discussed in detail and M. tropica var. indivisa (Nordst.) Eichl. et Racib., formerly known only from New Zealand, is figured from Tasmania. Some other Micrasterias forms are readily accommodated within the existing nomenclature. Others, however, have been uncertainly allied with existing taxa in keeping with a policy of not adding to the burden of nomenclature until a biological concept of species has been developed for the desmids. The taxonomy of Australian representatives of the genus Micrasterias is discussed against this background.     

VNTR loci reveal differentiation between and structure within populations of the eastern barred bandicoot Perameles gunnii

The Eastern Barred Bandicoot Perameles gunnii has declined in abundance within mainland south-eastern Australia, to a relict wild population of less than 100 individuals in Hamilton, Victoria. It is more common, but is also declining in Tasmania. Genomic DN A variability was compared within and between surviving populations of P. gunnii using variable number of tandem repeat (VNTR) markers in one of two ways. First, average percentage differences (APDs) were determined between profiles for two VNTR probe—endonuclease combinations. Secondly, because one of these combinations revealed two multiallelic VNTR loci, genotypes were assigned and analysed for homogeneity of allele frequencies among subpopulations, for deviation of heterozygosity from Hardy-Weinberg equilibrium within populations and for genetic structuring among individuals from different subpopulations. The results of both the APD and defined locus approaches showed consistent trends within and between populations. Genetic variability was higher among mainland P. gunnii than in Tasmanian populations (higher APDs, number of alleles, and heterozygosity at one locus), despite the known decline and subdivision of the Hamilton population. Eleven per cent of the variability detected in Hamilton was attributed to genetic differentiation between east and west subdivisions of the population. Departure from random mating indicating local inbreeding within collecting localities was evident for one locus in both north and south Tasmania, particularly at one locality. AH alleles at both loci were unique to either Hamilton or Tasmanian P. gunnii. The initial captive colony contains high heterozygosity for these loci. It is concluded that VNTR markers can be of benefit for use in studies of population differentiation and for conservation management.     

Biochemical characterisation of Australian strains of Echinococcus granulosus by isoelectric focusing of soluble proteins

The existence of three distinct strains of E. granulosus in Australia has been previously demonstrated on the basis of several criteria. In the present study, numerous isolates of E. granulosus from domestic and wild animal populations in different geographical areas of Australia were subjected to detailed biochemical analysis using isoelectric focusing of soluble proteins. Three different populations were recognised which corresponded to the three strains described previously, thus confirming their genetic distinction. One strain is common to all domestic intermediate hosts on the Australian mainland. Evidence is presented that humans and macropod marsupials are also susceptible to infection with this strain and that it is similar to E. granulosus occurring in sheep in New Zealand and the United Kingdom. The other two strains are confined to macropod marsupials on the Australian mainland and sheep in Tasmania respectively.     

Reproductive potential of a marine ecosystem engineer at the edge of a newly expanded range

Global climate change is leading to redistribution of marine species and altering ecosystem dynamics. Given recent poleward range extension of the barrens‐forming sea urchin Centrostephanus rodgersii (Diadematidae) from mainland Australia to Tasmania, there is a need to understand the population dynamics of this ecologically important species in the Tasmanian environment. This paper informs possible population dynamics of C. rodgersii in Tasmania by examining its reproductive ecology in this new environment. Reproductive periodicity (gonad index and propensity to spawn) was assessed bimonthly over 18 months at four sites in eastern Tasmania spanning ～2° in latitude. At all sites, C. rodgersii displayed a strong seasonal cycle in gonad production with major spawning occurring in winter (～August) at minimum annual water temperature. Gametes from Tasmanian C. rodgersii were viable as determined by fertilization and early development trials. However, development to the two‐arm stage at ～3 weeks was strongly dependent on water temperature across the 8–20 °C temperature range, with poor development occurring below 12 °C. The range of temperatures tolerated by Tasmanian C. rodgersii larvae was similar to that of larvae from its native New South Wales range, indicating that this species has not undergone an adaptive shift to the cooler Tasmanian environment. There was also no evidence for an adaptive shift in reproductive phenology. Importantly, coastal water temperatures in eastern Tasmania during the peak spawning in August fluctuate about the 12 °C larval development threshold. Recent warming of the eastern Tasmanian coast and further warming predicted by global climate change will result in an environment increasingly favourable for the reproduction and development of C. rodgersii.