Petrogale Lateralis Research Articles

Population structure and genetic diversity of the black-footed rock-wallaby (Petrogale lateralis MacDonnell Ranges race)

Genetic diversity is a critical determinant of the persistence of populations because it enables animals to evolve and adapt to environmental change. Black-footed rock-wallabies (Petrogale lateralis MacDonnell Ranges race), or warru, once occupied virtually all suitable habitat within the arid zone of central Australia. However, only two metapopulations now remain in the southern portion of this race’s range (South Australia) and a recovery program has involved both in- and ex-situ conservation initiatives. To establish whether genetic factors such as inbreeding may be inhibiting population recovery, the current study examined the population structure and genetic diversity of animals in the three largest-known extant colonies using six polymorphic microsatellite loci. Bayesian and frequency-based assignment tests revealed substantial population structuring (pairwise FST values 0.122–0.278), congruent with geographically distinct colonies. There was some evidence of dispersal, with two migrants identified across two colonies, but little evidence for extensive interbreeding among colonies. Population substructure was evidenced by high values of FIS in one colony. All populations possessed relatively high levels of genetic diversity (allelic richness: 5.1–7.5, heterozygosity: 0.70–0.72). On the basis of a genetic analysis of parentage, approximately half of all males and females in the known metapopulations produced offspring. This has likely contributed to the retention of genetic diversity across colonies. These findings have implications for the management of both the in- and ex-situ warru populations.

Fine-scale genetic structure and the design of optimal fertility control for an overabundant mammal

Hormonally-induced fertility control is increasingly used to manage overabundant wildlife where political or ethical considerations exclude culling or translocations. By altering reproductive rates, fertility control risks accelerating the loss of genetic variation from isolated wildlife populations if control is biased against particular genotypes. This is most likely in spatially structured populations, but information on patterns of genetic exchange can be difficult to ascertain by observation or trapping. Fertility control was proposed to manage an isolated but overabundant population of the black-flanked rock-wallaby, Petrogale lateralis lateralis, at Mt Caroline Nature Reserve, south-western Australia. This species typically inhabits large granite outcrops, where refuges within outcrops are often patchily distributed, and there is strong potential for population structure. We used fine-scale analysis of microsatellite DNA variation to establish the pre-fertility control extent of population structuring and the relative extent of gene flow in males and females in an isolated population of black-flanked rock-wallabies. Bayesian model-based clustering and fixation statistics revealed that overall gene flow is extensive, but two areas of refuge were genetically distinct from distant neighbours. Spatial autocorrelation analyses indicated that female-mediated gene flow was less extensive than male-mediated gene flow. Our results indicate that it would be desirable to apply fertility control to female rock wallabies within defined genetic isolates, but fertility control could be applied in a spatially random manner to males.

The Mark II Bromilow Kinnear humane soft trap: a major upgrade

The Bromilow soft trap was originally created to counter the propensity of black-flanked rock-wallabies (Petrogale lateralis lateralis, hence black-flanked) to harm themselves in wire traps. It achieved that goal commendably and has proven to be durable and versatile as it is also suitable for trapping other medium-sized mammals. Major improvements have been incorporated without altering the basic design thus enabling existing traps to be readily upgraded. The traps are now 15% lighter, and easier to set with a new more reliable trigger. The shroud has been discarded, and it now folds more compactly for transport and storage. The capture chamber is constructed of new materials designed to enable an animal to be extracted more readily. These modifications are described in detail along with illustrations. For anyone intending on building a new trap, free professional-grade architectural drawings of the framework and components are available via the web (see text).

The success of GPS collar deployments on mammals in Australia

Global Positioning System (GPS) wildlife telemetry collars are being used increasingly to understand the movement patterns of wild mammals. However, there are few published studies on which to gauge their general utility and success. This paper highlights issues faced by some of the first researchers to use GPS technology for terrestrial mammal tracking in Australia. Our collated data cover 24 studies where GPS collars were used in 280 deployments on 13 species, including dingoes or other wild dogs (Canis lupus dingo and hybrids), cats (Felis catus), foxes (Vulpes vulpes), kangaroos (Macropus giganteus), koalas (Phascolarctos cinereus), livestock guardian dogs (C. l. familiaris), pademelons (Thylogale billardierii), possums (Trichosurus cunninghami), quolls (Dasyurus geoffroii and D. maculatus), wallabies (Macropus rufogriseus and Petrogale lateralis), and wombats (Vombatus ursinus). Common problems encountered were associated with collar design, the GPS, VHF and timed-release components, and unforseen costs in retrieving and refurbishing collars. We discuss the implications of collar failures for research programs and animal welfare, and suggest how these could be avoided or improved. Our intention is to provide constructive advice so that researchers and manufacturers can make informed decisions about using this technology, and maximise the many benefits of GPS while reducing the risks.

The identity of the Depuch Island rock-wallaby revealed through ancient DNA

Ancient DNA is becoming increasingly recognised as a tool in conservation biology to audit past biodiversity. The widespread loss of Australian biodiversity, especially endemic mammal populations, is of critical concern. An extreme example occurred on Depuch Island, situated off the north-west coast of Western Australia, where an unidentified species of rock-wallaby (Petrogale sp.) became extinct as a result of predation by red foxes. Two potential candidate species, Petrogale lateralis and P. rothschildi, both have ranges adjacent to Depuch Island, making identification based on geography difficult. A museum bone (one of the only surviving Depuch Island specimens) was subjected to standard ancient DNA analyses and procedures. Mitochondrial DNA cytochrome b and hypervariable control region were targeted for species identification. Ancient DNA was successfully recovered from the bone: 200 base pairs (bp) of control region and 975 bp of the cytochrome b gene. Bayesian phylogenetic analyses were employed to model the Depuch Island rock-wallaby DNA sequences together with sequences of other rock-wallaby taxa from GenBank. Evidence suggests that of the two Petrogale lateralis subspecies proposed to have inhabited Depuch Island, Petrogale lateralis lateralis was identified as the most likely. The identification of the Depuch Island rock-wallaby population may assist in the reintroduction of an insurance population of Petrogale lateralis lateralis, which is becoming increasingly threatened on mainland Australia.

Haematology and biochemistry of warru (Petrogale lateralisMacDonnell Ranges race) in captivity and the wild

Use haematology, biochemistry and protein electrophoresis analyses to establish reference values for, and describe the health status of, wild and captive colonies of critically endangered warru (black-footed rock-wallaby: Petrogale lateralis MacDonnell Ranges race). Blood samples were taken from warru in three wild colonies (Alalka, Kalka, New Well) in the A nangu Pitjantjatjara Yankunytjatjara Lands in north-west South Australia (SA) and from captive animals at Monarto Zoo, SA. General haematology, serum biochemistry and protein electrophoresis analyses were conducted and results used to establish reference ranges. For the parameters that are indicative of a population's health, comparisons among the study sites were completed using analysis of variance. General haematology results suggested that warru were not experiencing chronic anaemia and the protein electrophoresis values indicated that colonies were not suffering from population-wide disease. However, the lower superoxide dismutase, retinol, total carotenoids and ascorbic acid values for New Well warru suggested those animals had a lower plane of nutrition than those at Kalka and Alalka. Higher urea concentrations in New Well and Alalka warru could be a reflection of the absence of reliable free water at these sites. The results have implications for the management of in situ colonies, including potentially using supplementary feeding to improve nutrition, and suggested that these animals were not suffering from disease. The study presents the first blood reference values for P. lateralis and, potentially, a methodology for other threatened species recovery programs to follow to establish the health of their populations.

The warru (Petrogale lateralis MacDonnell Ranges Race) reintroduction project on the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia

SummaryThe Black‐footed Rock‐wallaby (Petrogale lateralis MacDonnell Ranges Race), or warru, as it is known by Anangu, the traditional owners of the region, formerly inhabited the rocky hills of the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in north–west South Australia. However, introduced carnivores and inappropriate fire regimes have decimated the population, and there are now only 150–200 animals remaining in the wild. This prompted the formation of the Warru Recovery Team (WRT), a collaboration between Traditional Owners, Anangu communities and scientists, who are working together to recover warru populations across the APY Lands. The team are working on the Warru Reintroduction Project, which is combining modern science and the traditional ecological knowledge of Anangu to reintroduce warru back into the APY Lands. Between 2007 and 2009, 22 iti‐warru (warru‐joeys) were taken to Monarto Zoo (Monarto, South Australia) to initiate the captive population. These zoo‐warru have successfully bred in captivity, and in 2011, six founder animals and five captive bred warru were returned to the APY Lands. They are being held in a 97‐ha predator‐proof warru enclosure that will allow zoo‐warru to adjust to the local environment and to learn the survival skills of their ancestors, prior to being released into the wild. Lessons learnt from the release of warru into warru pintji will inform future release situations, as well as management of the in situ warru population, which remains the priority of the WRT.

Bringing back warru: initiation and implementation of the South Australian Warru Recovery Plan

The warru, or black-footed rock-wallaby (Petrogale lateralis MacDonnell Ranges race), has continued to declined dramatically in range and abundance in South Australia over the last 80 years, and is now considered to be one of the state’s most endangered species. This paper documents key indicators of this decline and provides context for both the formation of the Warru Recovery Team, and the development of the objectives and actions of the Warru Recovery Plan. Warru decline is considered to be a symptom of ecosystem dysfunction in the central Australian ranges, yet warru recovery provides an opportunity for broadscale ecosystem recovery in this remote region. Full engagement of Anangu, research-based adaptive ecosystem management, and inclusive, strategic and sustainable management of the recovery process, are considered integral to meeting the objectives of the Warru Recovery Plan.

Biology and population dynamics of the black-flanked rock-wallaby (Petrogale lateralis lateralis) in the central wheatbelt of Western Australia

Through a mark–recapture study, we explored aspects of the biology and population dynamics in the largest known population of the black-flanked rock-wallaby (Petrogale lateralis lateralis) at Mt Caroline Nature Reserve, in the Western Australian wheatbelt in 2007–10. The body condition index of males and females varied significantly over time but fluctuated similarly for both sexes. Males and females followed a pattern of best condition in early summer, declining through autumn and reaching their poorest condition in early spring. Body condition was closely related to rainfall in the period ~3–6 months before trapping sessions. Births occurred throughout the year with two reproductive peaks, in autumn and late winter/spring. Reproductive rates averaged over 90% annually, except in 2007 when they averaged 76%. Significantly fewer females bred during 2007, and those females were in poorer body condition. Females with a higher body condition index were more likely to reproduce (P = 0.003) but body condition did not influence the sex of offspring. The sex ratio of offspring did not differ significantly from parity and did not support either the Trivers–Willard or local resource competition hypotheses. This information should help to predict population trends and develop appropriate conservation strategies for this threatened species.

The impact of isolation and bottlenecks on genetic diversity in the Pearson Island population of the black-footed rock-wallaby (Petrogale lateralis pearsoni; Marsupialia:Macropodidae)

A morphologically distinct subspecies of black-footed rock-wallaby (Petrogale lateralis pearsoni), is naturally found only on North Pearson Island (~160 ha) in the Investigator Group, SA, where it was isolated by rising sea levels ~10 500 years ago. Subsequent translocations have seen additional populations established on Middle-South Pearson Island (~53 ha) in 1960 and Wedge Island (96 ha) in 1975. We have used 10 hypervariable microsatellite loci to examine the levels of genetic diversity in the endemic (n = 38) and translocated (n = 45–77) P. l. pearsoni populations compared with mainland P. lateralis populations (n = 19–52). Results show that all sampled P. l. pearsoni populations have very low levels of genetic diversity (A = 1.5–1.9; HE = 0.02–0.13) compared with mainland populations (A = 3.5–12.7; HE = 0.54–0.87). Intriguingly, more diversity was detected in the translocated Middle-South Pearson population than in its source population from North Pearson Island. In contrast, the Wedge Island population was almost monomorphic. Overall, the severe loss of genetic diversity (up to 98%) in P. l. pearsoni populations appears to result from random genetic drift on a small isolated population, exacerbated by some subsequent one-off translocation events. Although additional supplementary translocations are recommended to enhance genetic diversity, populations of P. l. pearsoni are likely to remain inherently vulnerable to extinction and therefore of special conservation concern.

Status of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands of South Australia. 1. Distribution and decline

Surveys for warru (Petrogale lateralis MacDonnell Ranges race) were conducted in targeted areas of the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands in order to clarify the distribution and status of the taxon in South Australia. Presence was determined by animal sightings or fresh scats. The study identified extant warru sites adjacent to known colonies in the Musgrave and Tomkinson Ranges, indicating that, in both locations, warru probably occur as larger metapopulations. The study highlighted that warru has disappeared from 93% of its former range across South Australia, and from 88% of its stronghold in the APY Lands. Accounting for recent information on population dynamics, this study has confirmed that warru are ‘Endangered’ in South Australia, and a more thorough assessment of the race’s current national distribution and status is required.

Status of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands of South Australia. 2. Population dynamics

The population dynamics of warru (Petrogale lateralis MacDonnell Ranges race) were studied in the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia, in order to inform management and better understand the race’s conservation ecology. Mark–recapture between 2005 and 2010 at the three largest known remaining colonies, followed by POPAN modelling, indicated that population sizes were 23 at New Well and 24 at Alalka in the Musgrave Ranges, and 14 at Kalka in the Tomkinson Ranges. Taking into account recent survey results, the study confirmed that warru are ‘Endangered’ in South Australia. However, there is potential for the recovery of the race, with high average reproductive rates (in the Musgrave Ranges >90% of reproductively active females had pouch young), even sex ratios and relatively high adult survivorship (>75%). Juvenile survival (51%), however, was significantly lower than that of adults. Given that red fox (Vulpes vulpes) numbers are low at these sites, this is possibly due to predation by feral cats (Felis catus), although this needs further investigation. Juvenile survival was also positively correlated with winter rainfall, possibly indicating that access to water is important during the drier winter months. In light of these observations, it is proposed that management of remaining warru colonies focus on cat control and consider providing access to free water during winter, as well as addressing landscape-scale threats such as wildfire and the spread of exotic plants.

Preliminary spatial behaviour of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia

This study aimed to determine the home range and movement patterns of Petrogale lateralis in the arid-zone Anangu Pitjantjatjara Yankunytjatjara Lands in the north-west of South Australia. Ten Global Positioning System radio-collars were attached to animals, with collars programmed to function in 2008–09. Catastrophic collar failure resulted in only 28 days of data, from July 2008, being retrieved from one adult female. During this time, the female occupied a 90% kernel range of 57.9 ha and core (50%) range of 9.3 ha. The animal moved a total of 50.8 km and undertook three journeys of over 1 km. The longest of these was 1.2 km, undertaken in 89 min. The high mobility of the study animal has implications for management, particularly predator baiting and fire management strategies. Future research should assess the validity of these results by increasing sample size and conducting similar work for other arid-zone P. lateralis. The lessons learnt from the current GPS collar deployment may also be of interest to other researchers.

Bronchogenic carcinoma in a male rock wallaby (Petrogale lateralis lateralis)

Rock wallabies (Petrogale spp.) often occur on isolated rocky outcrops in low-rainfall areas. One male wallaby, from a population of black-flanked rock wallabies (P. lateralis lateralis) being surveyed as part of an ecology and fertility study, died following capture. Post mortem examination revealed the animal to be in poor condition with signs of chronic stress and an extensive, metastasising bronchogenic carcinoma.

Reduced MHC class II diversity in island compared to mainland populations of the black-footed rock-wallaby (Petrogale lateralis lateralis)

Many animal populations that are endangered in mainland areas exist in stable island populations, which have the potential to act as an “ark” in case of mainland population declines. Previous studies have found neutral genetic variation in such species to be up to an order of magnitude lower in island compared to mainland populations. If low genetic variation is prevalent across fitness-related loci, this would reduce the effectiveness of island populations as a source of individuals to supplement declining mainland populations or re-establish extinct mainland populations. One such species, the black-footed rock-wallaby (Petrogale lateralis lateralis), exists within fragmented mainland populations and small island populations off Western Australia. We examined sequence variation in this species within a fitness-related locus under positive selection, the MHC class II DAB β1 locus. The mainland populations displayed greater levels of allelic diversity (4–7 alleles) than the island population, despite being small and isolated, and contained at least two DAB gene copies. The island population displayed low allelic diversity (2 alleles) and fewer alleles per individual in comparison to mainland populations, and probably possesses only one DAB gene copy. The patterns of DAB diversity suggested that the island population has a markedly lower level of genetic variation than the mainland populations, in concordance with results from microsatellites (genotyped in a previous study), but preserved unique alleles which were not found in mainland populations. Where possible, conservation actions should pool individuals from multiple populations, not only island populations, for translocation programs, and focus on preventing further declines in mainland populations.

The measurement of luteinising hormone in the western grey kangaroo (Macropus fuliginosus ocydromus) and the black-flanked rock wallaby (Petrogale lateralis lateralis)

An enzyme immunoassay with an anti-bovine-LH antibody (518B7) was applied to female western grey kanagaroos (Macropus fuliginosus ocydromus) and black-flanked rock wallabies (Petrogale lateralis lateralis). Validation showed parallelism to the assay standard curve, and significant increases in plasma LH concentrations after challenging animals with intramuscular GnRH.

276. The technical and biological validation of an LH assay for use with the Western Grey Kangaroo (Macropus fuliginosis) and Black-flanked Rock Wallaby (Petrogale lateralis lateralis)

Methods for the measurement of marsupial LH invariably rely upon the similarity of the LH molecule between different species and usually use anti-ovine or anti-bovine LH antibody and an ovine or bovine labelled LH preparation. Initial attempts to measure plasma LH in the Western Grey Kangaroo with assays using antibodies to 4 different isoforms of ovine LH raised in 7 different rabbits were unsuccessful. An enzymeimmunoassay (EIA) developed for the Asian elephant (Zoo Biology 23:45–63) was then applied to the Western Grey Kangaroo and the Black-flanked Rock Wallaby. This EIA has an anti-bovine-LH monoclonal antibody (518B7 provided by Dr Jan Roser, University of California, Davis, USA), biotinylated ovine LH label and bovine LH standard (NIADDK-oLH-26 and NIH-bLH-B10, both provided by Dr Janine Brown and Nicole Abbondanza, Smithsonian Institute, Front Royal, Virginia USA). Technical validation showed that serial dilution down to 1:8 of plasma from 7 individuals of each species showed parallelism to the assay standard curve, and control samples (1.24–5.30 ng/mL) had between-assay coefficients of variation <9%. Biological validation was achieved by challenging animals with intramuscular GnRH (Fertagyl®, 2.5 µg/kg) and measuring LH before and 25 min after the injection. Significant increases in plasma concentrations of LH (mean ± sem; all P > 0.0005) were seen after GnRH for both the Western Grey Kangaroo (from 5.0 ± 0.8 ng/mL to 9.4 ± 1.2 ng/mL; n = 19) and the Black-flanked Rock Wallaby (from 6.0 ± 0.7 ng/mL to 10.6 ± 0.6 ng/mL; n = 28). In conclusion, this assay can be successfully used to measure LH in these two species.

Comparative water metabolism of Barrow Island macropodid marsupials: Hormonal versus behavioural-dependent mechanisms of body water conservation

Seasonal variations in rates of water turnover were measured over a 7-year period in four species of macropodid marsupials ( Lagorchestes conspicillatus, Bettongia lesueur, Petrogale lateralis and Macropus robustus isabellinus), on Barrow Island off the arid Pilbara coast of Western Australia. These ranged from over 100 mL kg −0.82 d −1 in wet seasons to as low as 28.2 mL kg −0.82 d −1 in dry seasons in the Spectacled hare wallaby, L. conspicillatus. Plasma osmolality increased significantly in both Barrow Island euros ( M. robustus isabellinus) and Spectacled hare wallabies in November 1994, in the driest year yet recorded on the island. In contrast, there was no change in plasma osmolality of the other two species (Black-footed rock wallaby, P. lateralis and Lesueur’s burrowing bettong, B. lesueur) that exploit cool and humid thermal refugia such as caves and underground warrens to avoid diurnal temperature extremes. Plasma levels of the marsupial antidiuretic hormone (ADH), lysine vasopressin (LVP), were for the most part below the detectable limit of the assay of 0.41 pg mL −1 in rock wallabies and bettongs, but reached high levels of 16.7 ± 4.6 pg mL −1 and 20.25 ± 5.1 pg mL −1 in euros and hare wallabies, respectively, in dry seasons. LVP levels were positively correlated with plasma osmolality in both euros and hare wallabies, and negatively correlated with total body water content in euros, supporting its rôle as an antidiuretic hormone in these two species. The study highlights the importance of environmental features, such as caves and underground warrens, which are critical for the long-term survival of endangered species such as the Black-footed rock wallaby and the Lesueur’s bettong. These species appear to lack ADH-controlled renal systems for the conservation of body water and are thus dependent on behavioural strategies for the maintenance of fluid homeostasis in arid environments.

New Host Records, Redescriptions and New Species of Labiostrongylinea (Nematoda: Chabertiidae) from Macropodid Marsupials, with a Revised Host-Parasite Checklist

SummaryNew host records: from Macropus rufogriseus for Labiosimplex clelandi, M. robustus for Ls. aridus, Thylogale stigmatica for Ls. thetidis, and M. parma for Ls. bancrofti are reported. On re-examination of all material, Labiosimplex quasibancrofti was found to be morphologically indistinguishable from Ls. australis and is therefore a synonym of Ls. australis. A new species of Labiomultiplex, described from a single female from M. parma, is differentiated by the shape of the lateral lips and Lm. kimberleyensis is redescribed from additional material collected from the type-host, Onychogalea fraenata, from Queensland. Two new species of Labiosimplex are described from macropodid marsupials from central Australia. Labiosimplex centralis sp. nov. from the stomach of Petrogale lateralis differs from the most similar of its congenors, Ls. thomasae (both lacking a gubernaculum), in having shorter spicules, a shorter dorsal lobe of the bursa, and in the form of the dorsal ray. Labiosimplex territoriensis sp. nov. from the stomach of M. antilopinus differs from all its congenors in having large multi-lobed oesophago-intestinal diverticula. A new species, Labiostrongylus arnhemensis sp. nov. from the stomach of M. bernardus from the Northern Territory, differs from its congenors in a suite of characters including the position of the deirids, the shape of the oesophago-intestinal diverticula, the length of the dorsal lobe of the bursa, the morphology of the genital cone and gubernaculum and the length of the female tail. A revised host-parasite checklist, including Labiostrongylinea from the island of New Guinea together with those occurring in Potoroidae, is given.

Late Quaternary vegetation change and the extinction of Black-flanked Rock-wallaby ( Petrogale lateralis) at Tunnel Cave, southwestern Australia

Quaternary vertebrate extinctions attract wide interest because of the role ascribed to humans as agents of extinction, through either over-hunting or altering habitat. This paper examines faunal and floral records from the archaeological site at Tunnel Cave, Leeuwin–Naturaliste Region, southwestern Australia, which are relevant to the Mid-Holocene local extinction of Black-flanked Rock-wallaby ( Petrogale lateralis). Possible factors causing the population decline include inter-species competition, over-hunting by humans or other predators, or vegetation habitat change caused by climate change or changes in human firing practices. Identification of macroscopic charcoal excavated at Tunnel Cave shows that changes in canopy trees began from 10,000 BP, consistent with post-glacial rainfall increases, and probably causing the encroachment of closed habitats and loss of grazing areas. These changes are consistent with other faunal shifts at Tunnel Cave and with faunal and identified charcoal records from the nearby Devil's Lair deposit. There is little evidence for changes in competitor or predator behaviour, although increasing geographic isolation of Petrogale habitats possibly exacerbated predator impacts. The timing of human occupations at Tunnel Cave in relation to vegetation change suggests that human firing was a minor influence on forest composition or structure. Petrogale's Mid-Holocene disappearance from the region is therefore attributable to climatically driven encroachment of closed habitat.