Australian Arid Zone Research Articles

Burrow use by bilbies in temperate South Australia

Remnant natural populations of greater bilbies (Macrotis lagotis) are confined to the Australian arid zone where bilbies construct and shelter in multiple burrows within their home range. We investigated burrow use behaviour of bilbies in a translocated population in temperate southern Australia to determine if behaviour differed in this climatic zone. Over a 12 month period, 43 adult bilbies at Venus Bay Conservation Park were spool-and-line tracked to 118 burrows. Active burrow density was 0.55 per ha, and bilbies at the site used multiple burrows (up to 13 for males and 8 for females) and regularly moved between diurnal burrows. Male bilbies had significantly larger burrow ranges (10.2 ± 5.8 ha, MCP100, mean ± s.d.) than females (2.6 ± 1.8 ha), and were similar in size to those recorded in an arid zone population. Males’ burrow ranges tended to overlap with the burrow range of multiple other males and females. The density of burrows in the current study suggests that bilby burrows were likely to have been a common landscape feature within the southern parts of the species range prior to their local extinction. Further research is needed to determine the impact of the loss of bilby burrows from southern Australia on other burrow commensal species.

Ranking buffel: Comparative risk and mitigation costs of key environmental and socio-cultural threats in central Australia.

Changed fire regimes and the introduction of rabbits, cats, foxes, and large exotic herbivores have driven widespread ecological catastrophe in Australian arid and semi‐arid zones, which encompass over two‐thirds of the continent. These threats have caused the highest global mammal extinction rates in the last 200 years, as well as significantly undermining social, economic, and cultural practices of Aboriginal peoples of this region. However, a new and potentially more serious threat is emerging. Buffel grass (Cenchrus ciliaris L.) is a globally significant invader now widespread across central Australia, but the threat this ecological transformer species poses to biodiversity, ecosystem function, and culture has received relatively little attention. Our analyses suggest threats from buffel grass in arid and semi‐arid areas of Australia are at least equivalent in magnitude to those posed by invasive animals and possibly higher, because unlike these more recognized threats, buffel has yet to occupy its potential distribution. Buffel infestation also increases the intensity and frequency of wildfires that affect biodiversity, cultural pursuits, and productivity. We compare the logistical and financial challenges of creating and maintaining areas free of buffel for the protection of biodiversity and cultural values, with the creation and maintenance of refuges from introduced mammals or from large‐scale fire in natural habitats. The scale and expense of projected buffel management costs highlight the urgent policy, research, and financing initiatives essential to safeguard threatened species, ecosystems, and cultural values of Aboriginal people in central Australia.

Female reproductive suppression in an Australian arid zone rodent, the spinifex hopping mouse

AbstractThe spinifex hopping mouse (Notomys alexis) is an Australian arid zone rodent that undergoes boom and bust population cycles in its natural environment. Most populations studied to date have been sympatric with exotic predators and introduced herbivores, likely affecting their population dynamics. Therefore, it is unclear whether high‐density populations of hopping mice are regulated by purely extrinsic factors or whether intrinsic factors are also at play. We hypothesized that reproductive suppression of female N. alexis may occur in high‐density populations as has been observed in some other rodent species. Reproductive condition of adult female N. alexis was compared between a high‐density population within the Arid Recovery reserve, where exotic predators and introduced herbivores are excluded, and a low‐density population on adjacent pastoral properties (no exclusions). Trap success was 10 times higher inside the reserve than at pastoral sites, and no adult females were observed breeding in the reserve population, despite 26 % of females at pastoral sites recorded breeding. Our results indicate that adult female N. alexis in the high‐density reserve population were reproductively suppressed, but the similar sex ratios in both populations and the high female body mass and body condition in the reserve indicated that this was not due to demographic differences between the two populations or food scarcity. Our study indicates that the ‘busts’ observed in arid zone rodent populations may be amplified due to the presence of exotic predators and/or grazing by introduced herbivores. We contend that prior to the introduction of exotic predators and introduced herbivores in Australia, the arid zone rodent N. alexis would likely have been more abundant and intrinsic population regulation through female reproductive suppression may have played a larger role in population regulation.

Do acoustically detectable species reflect overall diversity? A case study from Australia’s arid zone

AbstractIn recent years, passive acoustic monitoring has emerged as a reliable method for monitoring soniferous fauna, with numerous studies finding estimates of species richness and community composition are comparable with estimates derived from conventional field surveys. Most of these studies compare point counts of forest bird communities with contemporaneous short‐duration acoustic recordings, but several questions remain. How do these two methods compare in more open, arid ecosystems, how does applying methods optimally influence comparisons, and how do patterns in acoustically detectable species compare with overall patterns? Here we demonstrate techniques for improving sampling of acoustic data and conduct acoustic surveys to estimate species richness from ephemeral creek‐lines in the Australian arid zone using a long‐term passively derived acoustic dataset. We examine these results in the context of long‐term observer‐based transect surveys conducted along the same creek‐lines to define species within the avian assemblage that are acoustically detectable or acoustically undetectable/cryptic. Our data suggest that some species were consistently missed by acoustic surveys, but most belonged to groups that are typically excluded from inventories prior to analysis including rare species, raptors, waterbirds, swallows and nocturnal birds. Further, the relative diversities of sites were well estimated by acoustic surveys, with variations between sites reflecting those estimated by observer‐based field surveys. This suggests that in our study system, acoustically detectable species are reliable indicators of overall species richness. Field‐based surveys will remain an important component of sampling in arid ecosystems and we highlight the value of applying acoustic and conventional field‐based surveys in a complementary manner. This approach allows large, publishable datasets to be generated by exploiting the temporal reach of acoustic sensors, while also maximizing detections of acoustically cryptic species via field‐based surveys. We argue that acoustic monitoring has the potential to facilitate greater research effort in largely research‐deficient arid ecosystems.

Direct and indirect effects of carrion subsidies in an arid rangeland: Carrion has positive effects on facultative scavengers and negative effects on a small songbird

In the absence of top-down regulation by predators, herbivore populations irrupt. In irrupting populations of large herbivores deaths are frequent and availability of carrion from carcasses is high, potentially subsidising facultative scavengers such as crows and ravens. Increases in facultative scavengers could amplify perceived and real predation risk for small prey. We provisioned large-herbivore carcasses over 2 weeks at three sites (400 ha/site) in the Australian arid zone and monitored detection rates of facultative scavenger birds and low-nesting small passerines at these sites and at three control sites of the same size. We found that provisioning large herbivore carcasses rapidly increased local abundances of scavenging corvids Corvus coronoides and C. bennetti by 50% and decreased relative detection rates of a predation-sensitive small passerine, white-winged fairywren Malurus leucopterus by 50%. White-winged fairywren detection rates were inversely correlated with corvid abundances. Our study indicates that increases in carrion availability associated with herbivore irruptions subsidise facultative scavengers, and thus may indirectly affect co-occurring prey species.

Humulene Diepoxides from the Australian Arid Zone Herb Dysphania: Assignment of Aged Hops Constituents.

Dysphania is an abundant genus of plants, many of which are endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very few investigations into the phytochemistry of native Dysphania have been undertaken. Described herein, is the isolation and elucidation of two enantiomeric diastereomers of humulene diepoxide C from D. kalpari and D. rhadinostachya, of which unassigned diastereomers of humulene diepoxide C have been previously reported as components in beer brewed from aged hops. In addition, two (+)-humulene diepoxiols (humulene diepoxiol C-I and C-II) were isolated from D. rhadinostachya. Analysis of Chinook hops oil confirmed the presence of both humulene diepoxide C-I and C-II as trace components, and in turn enabled GC-MS peak assignment to the relative stereochemistry. Anticancer assays did not reveal any significant activity for the (+)-humulene diepoxides. Antifungal assays showed good activity against a drug-resistant strain of C. auris, with MIC50 values of 8.53 and 4.91 μm obtained for (+)-humulene diepoxide C-I and C-II, respectively.

Avian mortality risk during heat waves will increase greatly in arid Australia during the 21st century.

Intense heat waves are occurring more frequently, with concomitant increases in the risk of catastrophic avian mortality events via lethal dehydration or hyperthermia. We quantified the risks of lethal hyperthermia and dehydration for 10 Australian arid-zone avifauna species during the 21st century, by synthesizing thermal physiology data on evaporative water losses and heat tolerance limits. We evaluated risks of lethal hyperthermia or exceedance of dehydration tolerance limits in the absence of drinking during the hottest part of the day under recent climatic conditions, compared to those predicted for the end of this century across Australia. Increases in mortality risk via lethal dehydration and hyperthermia vary among the species modelled here but will generally increase greatly, particularly in smaller species (~10–42 g) and those inhabiting the far western parts of the continent. By 2100 CE, zebra finches’ potential exposure to acute lethal dehydration risk will reach ~ 100 d y−1 in the far northwest of Australia and will exceed 20 d y−1 over > 50% of this species’ current range. Risks of dehydration and hyperthermia will remain much lower for large non-passerines such as crested pigeons. Risks of lethal hyperthermia will also increase substantially for smaller species, particularly if they are forced to visit exposed water sources at very high air temperatures to avoid dehydration. An analysis of atlas data for zebra finches suggests that population declines associated with very hot conditions are already occurring in the hottest areas. Our findings suggest that the likelihood of persistence within current species ranges, and the potential for range shifts, will become increasingly constrained by temperature and access to drinking water. Our model adds to an increasing body of literature suggesting that arid environments globally will experience considerable losses of avifauna and biodiversity under unmitigated climate change scenarios.

Reflecting on siliceous rocks in central Australia: Using advanced remote sensing to map ancient “tool‐stone” resources

AbstractHyMap™ airborne hyperspectral imagery was used to discriminate and map hydrated silica mineralization in the Dalhousie Springs area of central Australia. A spectral feature fitting algorithm was used to match laboratory reference spectra with image pixel spectra, producing a scaled goodness‐of‐fit raster map of silicified “tool‐stone” sources in our study area. Subsequent fieldwork indicated that the algorithm mapped silcrete, a rock composed of hydrated silica, and incidentally, the most frequently utilized raw material for stone artifact manufacture in this area of the Australian arid zone. The soundness of our hydrated silica mineralization map is supported with field observations and spectroscopic analysis of collected silcrete samples. Independent siliceous rock mapping produced by the Commonwealth Scientific and Industry Research Organization offers additional corroboration of our results. Based on the success of our approach, we suggest that archaeologists working in Australia and in similar arid environments elsewhere have much to benefit in using advanced remote sensing products to map lithic resources, including time and cost‐saving advantages for field logistics, enriched assessments of land suitability for archaeological site types, and an improved understanding of resource distributions.

Comparison of Hyperspectral Versus Traditional Field Measurements of Fractional Ground Cover in the Australian Arid Zone

The collection of high-quality field measurements of ground cover is critical for calibration and validation of fractional ground cover maps derived from satellite imagery. Field-based hyperspectral ground cover sampling is a potential alternative to traditional in situ techniques. This study aimed to develop an effective sampling design for spectral ground cover surveys in order to estimate fractional ground cover in the Australian arid zone. To meet this aim, we addressed two key objectives: (1) Determining how spectral surveys and traditional step-point sampling compare when conducted at the same spatial scale and (2) comparing these two methods to current Australian satellite-derived fractional cover products. Across seven arid, sparsely vegetated survey sites, six 500-m transects were established. Ground cover reflectance was recorded taking continuous hyperspectral readings along each transect while step-point surveys were conducted along the same transects. Both measures of ground cover were converted into proportions of photosynthetic vegetation, non-photosynthetic vegetation, and bare soil for each site. Comparisons were made of the proportions of photosynthetic vegetation, non-photosynthetic vegetation, and bare soil derived from both in situ methods as well as MODIS and Landsat fractional cover products. We found strong correlations between fractional cover derived from hyperspectral and step-point sampling conducted at the same spatial scale at our survey sites. Comparison of the in situ measurements and image-derived fractional cover products showed that overall, the Landsat product was strongly related to both in situ methods for non-photosynthetic vegetation and bare soil whereas the MODIS product was strongly correlated with both in situ methods for photosynthetic vegetation. This study demonstrates the potential of the spectral transect method, both in its ability to produce results comparable to the traditional transect measures, but also in its improved objectivity and relative logistic ease. Future efforts should be made to include spectral ground cover sampling as part of Australia’s plan to produce calibration and validation datasets for remotely sensed products.

Basimarols A, B, and C, Highly Oxygenated Pimarane Diterpenoids from Basilicum polystachyon

The highly oxygenated pimarane diterpenoids basimarols A, B, and C (3-5) were isolated from the plant species Basilicum polystachyon, which was collected within the Australian arid zone. Structure elucidation was performed using a suite of spectroscopic techniques, including X-ray crystallography. Anticancer and anti-DENV activity of 3-5 was explored, but only limited activity was observed. More extensive antiviral evaluation of stachyonic acid A (1), which was also isolated from B. polystachyon, revealed broad spectrum antiviral activity against West Nile virus (Kunjin strain, WNVKun) and human influenza viruses H1N1 and H3N2.

Contrasting scales of local persistence between monsoonal and arid biomes in closely related, low‐dispersal vertebrates

AbstractAimFocussing on pairs of sister species across three genera of scincid lizards, we use genomic evidence to test for larger‐scale, late‐Pleistocene changes in distributions of lizards in the Australian arid zone (AZ) than in the adjacent monsoonal tropics (MT).LocationNorthern and central Australia.TaxonScincidae: Squamata.MethodsWe sequenced ~2000 nuclear exons and one mitochondrial gene across the distributions of species with primarily MT or AZ distributions from three genera of lizards. Using phylogenetic analysis and population structure analyses we identified major phylogeographic lineages and then compared the spatial scale of structuring and tested for recent demographic expansions.ResultsTwo genera in particular, Proablepharus and Morethia, showed deeper and more geographically localized phylogeographic diversity in the MT than the AZ. In the MT, localized diversity was prevalent in the relatively mesic regions. By contrast, the AZ was characterized by widespread and often genetically uniform lineages and a higher proportion of these had signals of recent population expansion.Main conclusionsConsistent with other recent, but mostly less genetically extensive studies, our results point to deeper and more localized diversity in MT compared to AZ. In turn, this suggests higher local persistence in more mesic and topographically diverse biome through the late Quaternary climate fluctuations. For the AZ, geographically extensive range expansions have likely contributed to the low spatial turnover of this exceptionally rich lizard fauna.

Isolation and Lack of Potential Mates may Threaten an Endangered Arid-Zone Acacia.

Clonality may provide reproductive assurance for many threatened plants while limiting sexual reproductive success either through energetic tradeoffs or because clones are self-incompatible. Most stands of the Australian arid-zone plant Acacia carneorum, flower annually but low seed set and an absence of sexual recruitment now suggest that this species and other, important arid-zone ecosystem engineers may have low genotypic diversity. Indeed, our recent landscape-scale genetic study revealed that stands are typically monoclonal, with genets usually separated by kilometers. An inability to set sexually produced seed or a lack of genetically diverse mates may explain almost system-wide reproductive failure. Here, using microsatellite markers, we genotyped 100 seeds from a rare fruiting stand (Middle-Camp), together with all adult plants within it and its 4 neighboring stands (up to 5 km distant). As expected, all stands surveyed were monoclonal. However, the Middle-Camp seeds were generated sexually. Comparing seed genotypes with the single Middle-Camp genotype and those of genets from neighboring and other regional stands (n = 26), revealed that 73 seeds were sired by the Middle-Camp genet. Within these Middle-Camp seeds we detected 19 genotypes in proportions consistent with self-fertilization of that genet. For the remaining 27 seeds, comprising 8 different genotypes, paternity was assigned to the nearest neighboring stands Mallee and Mallee-West, approximately 1 km distant. Ironically, given this species' vast geographic range, a small number of stands with reproductively compatible near neighbors may provide the only sources of novel genotypes.

Systematics of Haloniscus Chilton, 1920 (Isopoda: Oniscidea: Philosciidae), with description of four new species from threatened Great Artesian Basin springs in South Australia

AbstractRecent surveys of Australian arid-zone groundwater ecosystems have uncovered considerable species diversity and extreme endemism for the oniscidean isopod genus Haloniscus Chilton, 1920. Phylogenetic and species delimitation analyses have recognised several distinct species from the Great Artesian Basin springs in South Australia, inspiring a morphological reassessment of the genus and examination of specimens from the iconic Lake Eyre and Dalhousie Springs. We present a revised diagnosis of Haloniscus, transfer the genus from the family Scyphacidae to Philosciidae and describe four new species, H. fontanus Stringer, King & Taiti n. sp., H. microphthalmus Stringer, King & Taiti n. sp., H. rotundus Stringer, King & Taiti n. sp., and H. yardiyaensis Stringer, King & Taiti n. sp., based on combined morphological and molecular evidence. We compare the results of molecular-based species delimitation analyses with morphological data, provide distribution information, and present a key to the described species of Haloniscus. Two species presently included in Andricophiloscia Vandel, 1973, A. stepheni (Nicholls & Barnes, 1926) and A. pedisetosa Taiti & Humphreys, 2001, from Western Australia are also transferred to Haloniscus.

Too hot to handle: Cenozoic aridification drives multiple independent incursions of Schizomida (Hubbardiidae) into hypogean environments

The formation of the Australian arid zone, Australia’s largest and youngest major biome, has been recognized as a major driver of rapid evolutionary radiations in terrestrial plants and animals. Here, we investigate the phylogenetic diversity and evolutionary history of subterranean short-tailed whip scorpions (Schizomida: Hubbardiidae), which are a significant faunal component of Western Australian hypogean ecosystems. We sequenced two mitochondrial (12S, COI) and three nuclear DNA markers (18S, 28S, ITS2) from ∼600 specimens, largely from the genera Draculoides and Paradraculoides, including 20 previously named species and an additional 56 newly identified operational taxonomic units (OTUs). Phylogenetic analyses revealed a large and rapid species radiation congruent with Cenozoic aridification of the continent, in addition to the identification of a new genus in Western Australia and the first epigean schizomid from the Pilbara. Here, we also synonymise Paradraculoides with Draculoides (new synonymy), due to paraphyly and a lack of reliable characters to define the two genera. Our results are consistent with multiple colonisations of the subterranean realm from epigean ancestors as their forest habitat fragmented and retracted, with ongoing fragmentation and diversification of lineages underground. These findings illustrate the remarkable diversity and high incidence of short-range endemism of Western Australia’s subterranean fauna, which has important implications for identifying and managing short-range endemic subterranean fauna. They also highlight the advantages of including molecular data in subterranean fauna surveys as all specimens can be utilized, regardless of sex and life stage. Additionally, we have provided the first multi-gene phylogenetic framework for Australian schizomids, which will enable researchers and environmental consultants to identify new taxa or align them to existing lineages.

Rare plant species do not occupy water-remote refuges in arid environments subject to livestock grazing.

In many of the world's arid regions there has been a dramatic increase in grazing pressure with herds of livestock sustained by the provision of artificial water points. In these systems it has been suggested that grazing-sensitive plant species will have contracted to refuges distant from water points where grazing impacts are low. This association was tested using a large data set of presence/absence records for rare plant species throughout the northeastern Australian arid zone. The presence records of only one of 45 species were statistically associated with lower grazing activity, as a function of distance-to-water, than the absence records. The field observation that this species is rarely grazed suggests it is not susceptible to grazing pressure. In general, the study supports assertions that populations of short-lived plants in drylands are resilient in the face of exaggerated livestock grazing because herbivores are not in sufficient densities to have an impact during the sporadic periods of high rainfall when plants can complete their life cycles. However, long-lived palatable species may be extinction-prone in grazed landscapes over long time frames if recruitment is curtailed by grazing.

Recent range expansion in Australian hummock grasses (Triodia) inferred using genotyping-by-sequencing.

The Australian arid zone (AAZ) has undergone aridification and the formation of vast sandy deserts since the mid-Miocene. Studies on AAZ organisms, particularly animals, have shown patterns of mesic ancestry, persistence in rocky refugia and range expansions in arid lineages. There has been limited molecular investigation of plants in the AAZ, particularly of taxa that arrived in Australia after the onset of aridification. Here we investigate populations of the widespread AAZ grass Triodia basedowii to determine whether there is evidence for a recent range expansion, and if so, its source and direction. We also undertake a dating analysis for the species complex to which T. basedowii belongs, in order to place its diversification in relation to changes in AAZ climate and landscapes. We analyse a genomic single nucleotide polymorphism data set from 17 populations of T. basedowii in a recently developed approach for detecting the signal and likely origin of a range expansion. We also use alignments from existing and newly sequenced plastomes from across Poaceae for analysis in BEAST to construct fossil-calibrated phylogenies. Across a range of sampling parameters and outgroups, we detected a consistent signal of westward expansion for T. basedowii, originating in central or eastern Australia. Divergence time estimation indicates that Triodia began to diversify in the late Miocene (crown 7.0–8.8 million years (Ma)), and the T. basedowii complex began to radiate during the Pleistocene (crown 1.4–2.0 Ma). This evidence for range expansion in an arid-adapted plant is consistent with similar patterns in AAZ animals and likely reflects a general response to the opening of new habitat during aridification. Radiation of the T. basedowii complex through the Pleistocene has been associated with preferences for different substrates, providing an explanation why only one lineage is widespread across sandy deserts.

Changes in small native animal populations following control of European rabbits (Oryctolagus cuniculus) by warren ripping in the Australian arid zone

Context European rabbits have a great impact on native vegetation and small vertebrates in Australia. Rabbits consume vegetation and promote invasive plants and invasive predators, and compete directly and indirectly with native animals suppressing those populations. Aims We explored the changes in small native vertebrates and invertebrates following the removal of rabbits. Methods Warren ripping was undertaken on a property in south-western Queensland at four sites and the results of pitfall trapping were compared with four nearby paired control sites. Invertebrates and small mammals were counted in pitfall traps, and bird surveys were conducted in all treatment and control sites. Key results Following a rabbit-control program, we observed a four-fold increase in the number of dunnarts trapped in treatment plots, whereas no change was observed in control plots. The spring following the rabbit-control program also saw an increase in some lizards in treatment plots. Conclusions The presence of rabbits in arid-zone Australia can suppress native animal populations. Implications Many species of small native mammals and lizards rely on food sources that fluctuate greatly with environmental conditions. The presence of rabbits altering the landscape, supporting introduced predators, reducing vegetation and, therefore, insects, adds increased pressure for insectivorous species. Rabbit control through warren ripping in arid-zone Australia is an effective method to reduce rabbit numbers, and allowed for an increase in small vertebrates in treated areas.

Phylogenetic relationships and biogeographic history of the Australian trapdoor spider genus Conothele (Araneae: Mygalomorphae: Halonoproctidae): diversification into arid habitats in an otherwise tropical radiation

In Australia, climate change and continental drift have given rise to a complex biota comprising mesic specialists, arid-adapted lineages, and taxa that have arrived on the continent from Asia. We explore the phylogenetic diversity and biogeographic history of the Australian trapdoor spider genus Conothele Thorell, 1878 that is widespread in Australia’s monsoonal tropics and arid zone. We sequenced three mtDNA and five nuDNA markers from 224 specimens. We reconstructed the phylogenetic relationships among specimens and estimated the number of operational taxonomic units (OTUs) using species delimitation methods. The timing of divergences was estimated and ancestral area reconstructions were conducted. We recovered 61 OTUs, grouped into four major clades; a single clade represented by an arboreal ecomorph, and three fossorial clades. The Australian Conothele had a crown age of ~19 million years, and ancestral area reconstructions showed a complex history with multiple transitions among the monsoonal tropics, central arid zone, south-west and Pilbara bioregion. Conothele arrived on the continent during periods of biotic exchange with Asia. Since then, Conothele has colonised much of the Australian arid and monsoonal zones, during a period of climatic instability. The Pilbara bioregion harbours high lineage diversity, emphasising the role of climate refugia.

Persistence of rare species depends on rare events: demography, fire response and phenology of two plant species endemic to a semiarid Banded Iron Formation range

The association of rare plant species and Banded Iron Formation (BIF) ranges in semiarid Western Australia is a noted phenomenon. These ranges are also a focus of iron ore exploration and mining. Decisions and planning required for development, conservation and management resulting from this interest, often consider translocation of these threatened species. Nonetheless, little is known about the ecology of BIF-endemic species to support any such decisions. We assessed population structure, patterns of growth, mortality, recruitment, reproduction and in situ seedbank persistence for two declared rare flora species. The shrub Darwinia masonii, and sedge Lepidosperma gibsonii are endemic to an area <40 km2 on the south-western boundary of the Australian arid zone. Both species were found to be long lived and slow growing, with evidence for reliance on rare events such as fire, and high rainfall years, including, for some processes, consecutive high rainfall years for growth, reproduction and recruitment. Retrieval and germination of seed batches shows that both species’ seedbanks are long-lived, with seasonal dormancy cycling. This, together with the ability of mature plants to survive through years not supporting growth, and, for L. gibsonii, to resprout after fire, are key mechanism for persistence in this unpredictable and low rainfall environment.

Systematics of the Australian spiny trapdoor spiders of the genus Blakistonia Hogg (Araneae: Idiopidae).

A combined molecular and morphological approach was used to revise the Australian spiny trapdoor spiders of the genus Blakistonia Hogg. Where possible, our molecular approach used sequence data from the COI barcoding gene, which were analysed using Bayesian, RAxML and neighbour-joining approaches. These molecular data were combined with morphology to describe and diagnose the genus, to redescribe the type (and only previously valid) species, B. aurea Hogg, 1902, and to diagnose, describe and map 19 new species: B. bassi sp. n., B. bella sp. n., B. birksi sp. n., B. carnarvon sp. n., B. emmottiorum sp. n., B. gemmelli sp. n., B. hortoni sp. n., B. mainae sp. n., B. maryae sp. n., B. newtoni sp. n., B. nullarborensis sp. n., B. olea sp. n., B. parva sp. n., B. pidax sp. n., B. plata sp. n., B. raveni sp. n., B. tariae sp. n., B. tunstilli sp. n., and B. wingellina sp. n. The genus Blakistonia is found to be distributed throughout the Australian arid and semi-arid zones, from the Wheatbelt region of Western Australia to central Queensland and western Victoria.