Australian Arid Zone Research Articles

Phylogenetic systematics of the land snail Basedowena from the Australian arid zone: taxonomic revision with description of new taxa (Stylommatophora : Camaenidae)

The land snail Basedowena Iredale, 1937 currently comprises eight species that inhabit mountain ranges in the central Australian arid zone. By studying the variation in shell and genital anatomy and the differentiation in the mitochondrial markers 16S and COI, we revise the taxonomy of this camaenid and describe new taxa. We demonstrate that the current morphology-based classification has been misled by homoplasy mainly in shell shape. In fact, Basedowena as herein revised contains species with vastly different shells, which have so far been assigned to different genera. By contrast, these species have the same general genital anatomy in common and form a clade in the mitochondrial phylogeny. Based on these findings, we transfer Pleuroxia bethana, P. hinsbyi, P. elfina, P. oligopleura, P. polypleura, P. radiata, Montanomelon angatjana and Minimelon colmani to Basedowena. While Pleuroxia and Montanomelon are maintained as distinct genera, although with fewer species, the monotypic Minimelon becomes a junior synonym of Basedowena. We identify and describe three new Basedowena species (B. bicolor, sp. nov., B. holoserica, sp. nov., B. siparium, sp. nov.). A fourth new species differs substantially from all other arid zone camaenids and is hence placed in a new genus, Xeromelon, gen. nov. The revised delineation of Basedowena renders it now the most widespread camaenid genus in Australia. It is distributed throughout the Australian arid zone from Western Australia, via the Northern Territory and South Australia into New South Wales.

Arid awakening: new opportunities for Australian plant natural product research

The importance of plants and other natural reserves as sources for biologically important compounds, particularly for application in food and medicine, is undeniable. Herein we provide a historical context of the major scientific research programs conducted in Australia that have been aimed at discovering novel bioactive natural products from terrestrial plants. Generally speaking, the main approaches used to guide the discovery of novel bioactive compounds from natural resources have included random, ethnobotanical and chemotaxonomic strategies. Previous Australian plant natural product research campaigns appear to have lacked the use of a fourth strategy with equally high potential, namely the ecologically guided approach. In addition, many large studies have sampled plant material predominantly from tropical regions of Australia, even though arid and semi-arid zones make up 70% of mainland Australia. Therefore, plants growing in arid zone environments, which are exposed to different external stressors (e.g. low rainfall, high ultraviolet exposure) compared with tropical flora, remain an untapped reservoir of potentially novel bioactive compounds. Research of Australian arid zone plants that is ecologically guided creates a new opportunity for the discovery of novel bioactive compounds from plants (and potentially other biota) for application in health care, food and agricultural industries.

Varying levels of clonality and ploidy create barriers to gene flow and challenges for conservation of an Australian arid-zone ecosystem engineer,Acacia loderi

Acacia loderi, the ecosystem engineer of the endangered Acacia loderi Shrublands in arid eastern Australia, spans a persistent (> 15 000 year) but poorly studied landscape feature, the Darling River. We investigated the genetic structure of 19 stands of eight to > 1000 plants separated by < 300 km to test for variation in life histories between semi-arid and arid stands to the east and west of the Darling River, respectively. Eight of nine stands east of the Darling were exclusively sexual, whereas most of those to the west were clonal. Three western stands were monoclonal, two were polyploid, and one was a diverse mix of diploid and triploid phenotypes. Bayesian analysis revealed a complex genetic structure within the western stands, whereas the eastern stands formed only two genetic clusters. Conservation of small stands may require augmentation of genotypic diversity. However, most genotypic diversity resides within the eastern stands. Although arid zone stands of A. loderi are not always clonal, clonality and polyploidy are more common in the arid west. Clear demarcation of life histories either side of the Darling River may reflect ancient or contemporary effects of physical disturbance associated with the river channel, or cryptic environmental differences, with sexual and asexual reproduction, respectively, at a selective premium in the semi-arid east and arid west. The restricted distribution of clones and variation in clonality and polyploidy suggests that smaller stands may be vulnerable and warrant individual management.

Recruitment and abnormality incidence of a desert frog assemblage at an Australian copper mine

SummaryMetamorphlings of five desert frog species were assessed for morphological abnormalities adjacent to and remote from the Nifty Copper Mine in the Great Sandy Desert of Western Australia. Abnormality rates in the most abundant species Main's Frog (Cyclorana maini) at a remote pond were higher than that recorded in three of the four ponds adjacent to the mine. The overall abnormality rate of 2.5% therefore likely reflects the regional background levels at Nifty, which is lower than background levels at other Australian arid zone sites. Although higher rates of abnormalities were not detected in ponds adjacent to the mine, frog recruitment was inhibited in one brackish mine pond.

Determining optimal sampling strategies for monitoring threatened endemic macro-invertebrates in Australia

Conservation concern for imperilled invertebrates grows but action is stalled by data deficiency. Great Artesian Basin springs present a textbook case; they are hotspots for endemic invertebrate diversity, but a persistent struggle to conserve them remains because of a lack of data. Spring research outside Australia suggests that biases created by sampling regimes make compiling and comparing disparate data sources problematic. We compared existing methods and their efficacy for sampling diversity and abundance of spring macro-invertebrates (&gt;1mm) associated with sediment and vegetation within limnocrenic wetlands characteristic of Australian arid-zone artesian springs, with the aim of presenting an optimum sampling strategy. The three methods tested gave similar estimates of richness, but measures of abundance for each taxon were sensitive to method choice. Both richness and abundance were significantly different among springs and areas within each spring. Direct method comparisons such as this ensure consistency and comparability between past and future studies and provide a framework for future monitoring. Species richness can be assessed rapidly and disparate data sources can be combined. However, assessments requiring abundance will need to be sensitive to the biases created by species identity, method and area.

New species of Australian arid zone chelonine wasps from the genera Phanerotoma and Ascogaster (Hymenoptera: Braconidae) informed by the ‘Bush Blitz’ surveys of national reserves

Here we focus on the poorly studied braconid wasp subfamily Cheloninae for the arid zone of the Australian continent, using material, in part, resulting from comprehensive surveys of three arid zone reserves. The Bush Blitz programme is a multi-institutional project with the aim of documenting the diversity of the flora and fauna in Australia’s National Reserve System, with describing new species being a key focus of the programme. In total, 11 species from the genera Ascogaster and Phanerotoma are treated, with species’ delimitation based on both molecular and morphological data. Two species are redescribed (Phanerotoma behriae Zettel, 1988a and P. decticauda Zettel, 1988a) and nine species are described as new (Ascogaster brevivena sp. nov., A. ferruginegaster sp. nov., A. prolixogaster sp. nov., A. rubriscapa sp. nov., Phanerotoma bonbonensis sp. nov., P. bushblitz sp. nov., P. lutea sp. nov., P. nigriscapulata sp. nov. and P. witchelinaensis sp. nov.). Keys to the arid zone species of these two genera are provided, along with a species richness estimation of Australian chelonine wasps.

Experimental Evidence for Phonemic Contrasts in a Nonhuman Vocal System.

The ability to generate new meaning by rearranging combinations of meaningless sounds is a fundamental component of language. Although animal vocalizations often comprise combinations of meaningless acoustic elements, evidence that rearranging such combinations generates functionally distinct meaning is lacking. Here, we provide evidence for this basic ability in calls of the chestnut-crowned babbler (Pomatostomus ruficeps), a highly cooperative bird of the Australian arid zone. Using acoustic analyses, natural observations, and a series of controlled playback experiments, we demonstrate that this species uses the same acoustic elements (A and B) in different arrangements (AB or BAB) to create two functionally distinct vocalizations. Specifically, the addition or omission of a contextually meaningless acoustic element at a single position generates a phoneme-like contrast that is sufficient to distinguish the meaning between the two calls. Our results indicate that the capacity to rearrange meaningless sounds in order to create new signals occurs outside of humans. We suggest that phonemic contrasts represent a rudimentary form of phoneme structure and a potential early step towards the generative phonemic system of human language.

Genetic Divergence among Regions Containing the Vulnerable Great Desert Skink (Liopholis kintorei) in the Australian Arid Zone.

Knowledge of genetic structure and patterns of connectivity is valuable for implementation of effective conservation management. The arid zone of Australia contains a rich biodiversity, however this has come under threat due to activities such as altered fire regimes, grazing and the introduction of feral herbivores and predators. Suitable habitats for many species can be separated by vast distances, and despite an apparent lack of current geographical barriers to dispersal, habitat specialisation, which is exhibited by many desert species, may limit connectivity throughout this expansive region. We characterised the genetic structure and differentiation of the great desert skink (Liopholis kintorei), which has a patchy, but widespread distribution in the western region of the Australian arid zone. As a species of cultural importance to local Aboriginal groups and nationally listed as Vulnerable, it is a conservation priority for numerous land managers in central Australia. Analysis of mitochondrial ND4 sequence data and ten nuclear microsatellite loci across six sampling localities through the distribution of L. kintorei revealed considerable differentiation among sites, with mitochondrial FST and microsatellite F′ST ranging from 0.047-0.938 and 0.257-0.440, respectively. The extent of differentiation suggests three main regions that should be managed separately, in particular the southeastern locality of Uluru. Current genetic delineation of these regions should be maintained if future intervention such as translocation or captive breeding is to be undertaken.

A remote sensing spatio-temporal framework for interpreting sparse indicators in highly variable arid landscapes

The world's extensive and often remote arid landscapes are receiving increasing attention to maintain their ecological and productive values. Monitoring and management of these lands requires indicators and evidence of ecosystem condition and trend, generally derived from widely distributed and infrequently repeated site-based records. However adequate geographic representation and frequent site revisits are difficult to achieve because of the remoteness and vast extent of these landscapes. Interpreting such sparse ecological indicators is difficult, particularly within landscapes that are highly variable in space and time. To interpret ecological indicator data collected in such environments long-term patterns of natural landscape variability need to be understood.This paper presents a framework of landscape spatio-temporal variability within which to interpret ecological indicator data. This framework is based on long-term patterns of vegetation growth across the Australian arid zone, derived from twenty-five years of high temporal resolution National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) satellite imagery. We present a case study of the extensive Alinytjara Wilurara (AW) Natural Resource Management (NRM) region in far western South Australia to illustrate new insights about landscape function gained from this approach, and their implications for collection and interpretation of ecological indicator data. We illustrate how variability in vegetation response is expressed across the region, and how stratification based on active vegetation response differs from more commonly used biogeographic stratifications in this region. Lastly we demonstrate the unique patterns of long-term vegetation response for the major vegetation response classes. Average amount, seasonality, magnitude, timing and variability of vegetation response over time are used to characterise the natural “envelope” of variability of the new landscape classes.The study region showed low vegetation response in summer and higher response in winter. Onset of growth was earlier in the north and in ecosystems dominated by mallee vegetation. Cyclonic influence from the west was evident at the southern margin of the study region. The study demonstrates the landscape functional response of the study region, and presents a method whereby remote sensing reveals the landscape context within which to better interpret ecological indicator data collected in a highly variable landscape.

How to snap your cat: optimum lures and their placement for attracting mammalian predators in arid Australia

Context Automatically activated cameras (camera traps) and automated poison-delivery devices are increasingly being used to monitor and manage predators such as felids and canids. Maximising visitation rates to sentry positions enhances the efficacy of feral-predator management, especially for feral cats, which are typically less attracted to food-based lures than canids. Aims The influence of camera-trap placement and lures were investigated to determine optimal monitoring and control strategies for feral cats and other predators in two regions of semi-arid South Australia. Methods We compared autumn and winter capture rates, activity patterns and behaviours of cats, foxes and dingoes at different landscape elements and with different lures in three independent 6 km × 3 km grids of 18 camera-trap sites. Key results Neither visual, olfactory or audio lures increased recorded visitation rates by any predators, although an audio and a scent-based lure both elicited behavioural responses in predators. Cameras set on roads yielded an eight times greater capture rate for dingoes than did off-road cameras. Roads and resource points also yielded highest captures of cats and foxes. All predators were less nocturnal in winter than in autumn and fox detections at the Immarna site peaked in months when dingo and cat activity were lowest. Conclusions Monitoring and management programs for cats and other predators in arid Australia should focus on roads and resource points where predator activity is highest. Olfactory and auditory lures can elicit behavioural responses that render cats more susceptible to passive monitoring and control techniques. Dingo activity appeared to be inversely related to fox but not cat activity during our monitoring period. Implications Optimised management of feral cats in the Australian arid zone would benefit from site- and season-specific lure trials.

Independent Transitions between Monsoonal and Arid Biomes Revealed by Systematic Revison of a Complex of Australian Geckos (Diplodactylus; Diplodactylidae).

How the widespread expansion and intensification of aridity through the Neogene has shaped the Austral biota is a major question in Antipodean biogeography. Lineages distributed across wide aridity gradients provide opportunities to examine the timing, frequency, and direction of transitions between arid and mesic regions. Here, we use molecular genetics and morphological data to investigate the systematics and biogeography of a nominal Australian gecko species (Diplodactylus conspicillatus sensu lato) with a wide distribution spanning most of the Australian Arid Zone (AAZ) and Monsoonal Tropics (AMT). Our data support a minimum of seven genetically distinct and morphologically diagnosable taxa; we thus redefine the type species, ressurrect three names from synonymy, and describe three new species. Our inferred phylogeny suggests the history and diversification of lineages in the AAZ and AMT are intimately linked, with evidence of multiple independent interchanges since the late Miocene. However, despite this shared history, related lineages in these two regions also show evidence of broadly contrasting intra-regional responses to aridification; vicarance and speciation in older and increasingly attenuated mesic regions, versus a more dynamic history including independent colonisations and recent range expansions in the younger AAZ.

Design Theory and the Australian Tula Adze

The tula adze is a distinctive composite tool that was used in the Australian arid zone during the late Holocene. In this paper we use design theory to investigate why this particular tool form was so pervasive across time and space. Design theory provides a rational means for classifying tool designs and for determining why particular tool design classes were employed over others. We draw upon ethnographic and archaeological evidence to characterize the design of the tula adze and conclude that it is consistently the product of a “reliable” design strategy. We further determine that the high cost of a reliable design was chosen because the tula adze was employed in situations where failure could not be tolerated. Specifically, we argue that an important role of the tula adze was to manufacture wooden goods for not only personal use but more significantly for trade. The quantity and quality of these goods had an extremely strong bearing on the economic sustainability of arid zone Aboriginal groups.

Results from the first intensive dating program for pigment art in the Australian arid zone: insights into recent social complexity

The Canning Stock Route Project (Rock Art and Jukurrpa) has yielded the first radiocarbon dates for rock paintings in the Western Desert of Australia. We report on the results of a large-scale project to directly-date both charcoal and inorganic-pigmented pictographs using plasma oxidation combined with accelerator mass spectrometry. This project has yielded the largest number of art dates from any region in the world: one site alone has produced 12 art dates (from 30 collected samples). Our work advances the testing of the dating method through the systematic use of replicates and explores the methodological implications of dating very small samples (10–40 μg carbon). Thirty-six radiocarbon age determinations range from 3000 years ago to Modern. The results contribute to an understanding of art production in the Australian arid zone during a period of extreme cultural dynamism. We have demonstrated for the first time that significant late Holocene changes in discard rates of artefacts and technological organization of the extractive technologies of implements such seed-grinders is matched by a very high level of stylistic heterogeneity in the art – which has been systematically dated within and between dialect groups.

A new synthesis of the molecular systematics and biogeography of honeyeaters (Passeriformes: Meliphagidae) highlights biogeographical and ecological complexity of a spectacular avian radiation

The passerine family Meliphagidae (the honeyeaters) comprises 175–180 species in 40–50 genera. It is an iconic element of the Australo‐Papuan avifauna and also occurs in Indonesia and on remote Pacific Ocean islands. Building on previous molecular studies that have pioneered a renewed understanding of the family's circumscription and systematics, we present an updated phylogenetic and systematics synthesis of honeyeaters derived from 112 mostly Australian, New Guinean and Wallacean species‐ and subspecies‐rank taxa aligned across 9246 positions spanning four mitochondrial and four nuclear genes. We affirm many of the recent changes advocated to the group's genus‐level systematics and offer some further refinements. The group's radiation appears to coincide broadly with the aridification of Australia in the Miocene, consistent with the time of origin of diversification of extant lineages in several other groups of Australian organisms. Most importantly, the complexity of the biogeography underlying the group's spectacular radiation, especially within Australia, is now apparent. Foremost among such examples is the robust evidence indicating that multiple, independent lineages of honeyeaters, including several monotypic genera, are endemic to the Australian arid zone, presumably having diverged and evolved within it. Also apparent and warranting further study are the phenotypic diversity among close relatives and the remarkably disjunct distributions within some clades, perhaps implying extinction of geographically intermediate lineages. Given such complexity, understanding the evolution of this radiation, which has thus far been intractable, relies on integration of molecular data with morphology, ecology and behaviour.

Rock Art In Arid Landscapes: Pilbara And Western Desert Petroglyphs

This paper develops a testable model for understanding rock art within archaeological phases of the arid northwest Pilbara and Western Desert bioregions. It also presents the first multivariate analysis of foundational recording work undertaken almost 50 years ago, and deploys more recently recorded assemblages from the Burrup Peninsula (Murujuga) and the Western Desert. It establishes a framework for testable hypotheses about how art production in these adjacent bioregions through deep-time reflects information systems, emergent territoriality, group identity and signalling behaviour against a backdrop of climatic oscillations, including the LGM (23–18 ka), Antarctic Cold Reversal (14.5–12.5 ka) and intensification of ENSO (3.8–2 ka). The Pilbara piedmont has clearly defined gorges with major water sources; the Western Desert has uncoordinated drainage punctuated by well-watered but subdued ranges. We argue that rock art has been used to negotiate social identity in both contexts since each was first colonised. The role that art may have played in the formation of social networks in these different landscapes through time is the key focus of this paper. We hypothesise that the episodic use of art as signalling behaviour in the Australian arid zone can be linked to behavioural correlates and major archaeological phases with discrete signatures that can be tested from myriad sites.

Patterns of genotypic diversity suggest a long history of clonality and population isolation in the Australian arid zone shrub Acacia carneorum

For plants capable of both sexual and clonal reproduction, the relative frequency of these reproductive modes is influenced by genetic and ecological factors. Acacia carneorum is a threatened shrub from the Australian arid zone that occurs as a set of small, spatially isolated populations. Sexual reproduction appears to be very rare: despite regular flowering, only two populations set seed. It is not known whether this reflects an ancient pattern, or results from rapid land use changes following arrival of Europeans in the region 150 years ago. We assessed genotypic variation throughout the range of A. carneorum using AFLP markers, to elucidate the relative importance of clonal and sexual reproduction in this species’ history. Clonal diversity (CD) within populations ranged from 0 to 0.820 (mean CD = 0.270, SE = 0.094), but the relative abundances of genets were typically highly skewed. On average, the two fruiting populations had higher CD (mean CD = 0.590, SE = 0.265) than non-fruiting populations (mean CD = 0.179, SE = 0.077) (t = 2.315, p = 0.049), but most populations contained multiple genets. All genets were population-specific, and there was substantial divergence among populations (Φ ST = 0.690), implying a long history of isolation. We conclude that clonality has predominated in A. carneorum populations, with occasional sexual recruitment, and that current failure of most populations to set seed likely reflects both a long history of asexual reproduction and effects of habitat disturbance. Conservation of this species may benefit from translocations to increase genotypic diversity within populations.

Nucleotide sequence diversity in Velvet tobacco mottle virus: a virus with a unique Australian pathosystem

Velvet tobacco mottle virus (VTMoV) is a naturally occurring mirid-transmitted sobemovirus of native velvet tobacco (Nicotiana velutina) plants in the Australian arid zone. We have sequenced the coding region of a typical field isolate of VTMoV (isolate I-17-04, satellite-plus) and show that it differed by nine polymorphisms from the previously sequenced atypical ‘satellite-minus’ variant VTMoV-K1 (represented here as L-K1-04), while retaining the same genomic and amino acid sequence motifs. We also report that although L-K1-04 was confirmed to be free of detectable satellite RNA by gel electrophoretic assay, the satellite sequence was detected in it by RT-PCR assay. Nucleotide sequence variation among the RNA-dependent RNA polymerase open reading frames of 15 field and laboratory isolates identified four phylogenetic groups, but these did not show a pattern related to site or time of sampling. This result would be consistent with nucleotide sequence variants of VTMoV being dispersed widely by migrating adult mirid vectors.

Speciation on the Rocks: Integrated Systematics of the Heteronotia spelea Species Complex (Gekkota; Reptilia) from Western and Central Australia

The isolated uplands of the Australian arid zone are known to provide mesic refuges in an otherwise xeric landscape, and divergent lineages of largely arid zone taxa have persisted in these regions following the onset of Miocene aridification. Geckos of the genus Heteronotia are one such group, and have been the subject of many genetic studies, including H. spelea, a strongly banded form that occurs in the uplands of the Pilbara and Central Ranges regions of the Australian arid zone. Here we assess the systematics of these geckos based on detailed examination of morphological and genetic variation. The H. spelea species complex is a monophyletic lineage to the exclusion of the H. binoei and H. planiceps species complexes. Within the H. spelea complex, our previous studies based on mtDNA and nine nDNA loci found populations from the Central Ranges to be genetically divergent from Pilbara populations. Here we supplement our published molecular data with additional data gathered from central Australian samples. In the spirit of integrative species delimitation, we combine multi-locus, coalescent-based lineage delimitation with extensive morphological analyses to test species boundaries, and we describe the central populations as a new species, H. fasciolatus sp. nov. In addition, within the Pilbara there is strong genetic evidence for three lineages corresponding to northeastern (type), southern, and a large-bodied melanic population isolated in the northwest. Due to its genetic distinctiveness and extreme morphological divergence from all other Heteronotia, we describe the melanic form as a new species, H. atra sp. nov. The northeastern and southern Pilbara populations are morphologically indistinguishable with the exception of a morpho-type in the southeast that has a banding pattern resembling H. planiceps from the northern monsoonal tropics. Pending more extensive analyses, we therefore treat Pilbara H. spelea as a single species with phylogenetic structure and morphological heterogeneity.

Some like it cold: summer torpor by freetail bats in the Australian arid zone

Bats are among the most successful groups of Australian arid-zone mammals and, therefore, must cope with pronounced seasonal fluctuations in ambient temperature (T a), food availability and unpredictable weather patterns. As knowledge about the energy conserving strategies in desert bats is scant, we used temperature-telemetry to quantify the thermal physiology of tree-roosting inland freetail bats (Mormopterus species 3, 8.5g, n=8) at Sturt National Park over two summers (2010-2012), when T a was high and insects were relatively abundant. Torpor use and activity were affected by T a. Bats remained normothermic on the warmest days; they employed one "morning" torpor bout on most days and typically exhibited two torpor bouts on the coolest days. Overall, animals employed torpor on 67.9% of bat-days and torpor bout duration ranged from 0.5 to 39.3h. At any given T a, torpor bouts were longer in Mormopterus than in bats from temperate and subtropical habitats. Furthermore, unlike bats from other climatic regions that used only partial passive rewarming, Mormopterus aroused from torpor using either almost entirely passive (68.9% of all arousals) or active rewarming (31.1%). We provide the first quantitative data on torpor in a free-ranging arid-zone molossid during summer. They demonstrate that this desert bat uses torpor extensively in summer and often rewarms passively from torpor to maximise energy and water conservation.

Redescription of Eremiascincus fasciolatus (Günther, 1867) (Reptilia: Squamata: Scincidae) with clarification of its synonyms and the description of a new species.

We present an assessment of the systematic status of populations currently assigned to Eremiascincusfasciolatus across Australia using morphological data. Our analyses show that these populations actually comprise four species: a large and robust, narrow-banded taxon from eastern Queensland and three slender, desert-dwelling taxa from the western, northern, and south-eastern Australian arid zone respectively. These data necessitate: 1) the redescription of E.fasciolatus, a species endemic to the dry forests of eastern Queensland, 2) the resurrection of E. pallidus for the western taxon, 3) the resurrection of E. intermedius for the northern taxon, and 4) the description of the south-eastern desert-dwelling taxon, which largely occurs in the Lake Eyre Basin, as a new species. The new species, Eremiascincusphantasmus sp. nov., can be distinguished from congeners by its large size, pale color, depressed snout, and small circular ear opening, as well as by several scale characteristics. Body proportions, a depressed snout, small ear opening, and pale color suggest that this species is fossorial and predominantly occurs in habitats with loose substrate, such as dune systems and sandy plains. A synopsis of each species and a key to the narrow-banded species of Eremiascincus are provided.