The Mountain Pygmy-possum (
) is a critically endangered marsupial, endemic to alpine regions of southern Australia. We investigated the diet of a recently discovered population of the possum in ...northern Kosciuszko National Park, NSW, Australia. This new population occurs at elevations well below the once-presumed lower elevation limit of 1,600 m.
Faecal material was analysed to determine if dietary composition differed between individuals in the newly discovered northern population and those in the higher elevation southern population, and to examine how diet was influenced by rainfall in the southern population and seasonal changes in resource availability in the northern population.
The diet of
in the northern population comprised of arthropods, fruits and seeds. Results indicate the diet of both populations shares most of the same invertebrate orders and plant species. However, in the absence of preferred food types available to the southern population, individuals of the northern population opportunistically consumed different species that were similar to those preferred by individuals in higher altitude populations. Differing rainfall amounts had a significant effect on diet, with years of below average rainfall having a greater percentage composition and diversity of invertebrates. Seasonal variation was also recorded, with the northern population increasing the diversity of invertebrates in their diet during the Autumn months when Bogong Moths (
) were absent from those sites, raising questions about the possum's dependence on the species.
Measurable effects of rainfall amount and seasonal variation on the dietary composition suggest that predicted climatic variability will have a significant impact on its diet, potentially impacting its future survival. Findings suggest that it is likely that
is not restricted by dietary requirements to its current pattern of distribution. This new understanding needs to be considered when formulating future conservation strategies for this critically endangered species.
The Mountain Pygmy-possum Burramys parvus was first described from a fossil found in Wombeyan Caves, central-eastern New South Wales in 1895, with further fossils located in Buchan Caves in eastern ...Victoria and Jenolan Caves in central-eastern New South Wales (Broom 1896; Wakefield 1960; Hope 1982). In August 1966 a living individual was located in the University Ski Lodge on Mt Higginbotham in the Victorian Alps (Ride 1970; Dixon 1971). The first discovery of the species in New South Wales was an individual trapped in Kosciuszko National Park in early 1970 (Calaby et al. 1971). Over the next three decades Burramys parvus was located in three regional populations that were separated by low elevation river valleys in the subalpine and alpine areas of south-eastern Australia. These regional populations are located in Kosciuszko National Park in New South Wales, the Bogong High Plains area (including sub-populations on Mt Bogong, the Bogong High Plains and Mt Higginbotham) and at Mt Buller in Victoria. Highest densities and breeding females are largely confined to periglacial blockfields and blockstreams (termed boulderfields) at altitudes above 1400 m in Victoria and 1600 m in New South Wales (Caughley 1986; Mansergh and Broome 1994; Heinze and Williams 1998; Osborne et al. 2000; Heinze et al. 2004; Broome et al. 2005). The lower altitudinal limit roughly corresponds with the winter snowline of around 1370 m in altitude (Davis 1998). The New South Wales population was recently estimated at 613 + 92 individuals (Broome et al. 2005) and is restricted to small patches of preferred boulderfield habitat between South Ramshead in the Thredbo area north to Gungartan Pass in southern Kosciuszko National Park in an area measuring 30 km by 8 km (Caughley 1986; NSW National Parks and Wildlife Service 2002; Broome et al. 2005). As a result of the small population size, extremely restricted distribution and threats associated with ski-run development Burramys parvus has been listed as Endangered under both the Federal Environment Protection and Biodiversity Conservation Act 1999 and the New South Wales Threatened Species Conservation Act 1995.
Developing an understanding of the impact of climate on Australia's alpine flora is critical in anticipating the impacts of climate change. The dendroclimatological analysis of the Australian ...mainland's only alpine conifer, Podocarpus lawrencei Hook.f., may have particular significance in this regard. Unfortunately, eccentric tree-ring widths and frequent ring wedging have previously prevented dendroclimatic investigation of the species using core samples. In this study, we overcome this limitation by using full stem cross-sections collected from individuals killed during wildfire in 2003. Despite this advantage, ring wedging and poor circuit uniformity meant that crossdating was successful for portions or complete sections of only 56% of samples. Nevertheless, we constructed a crossdated chronology spanning 114-years (1888–2001) – the first for P. lawrencei. Climatological analysis revealed significant positive correlations with air temperature during spring of the growing season and significant negative correlations with monthly and seasonal snow variables as well as spring precipitation. Further analyses using 50-year moving windows reveal that responses to minimum air temperature and precipitation are unstable and periodically non-significant. Nevertheless, whilst correlation with mean maximum temperature during October and November (spring) of the growing season as well as the seasonal integration of snow cover exhibits variability throughout the analysis period, this variability appears to be independent of trends in both mean temperature and snow cover. We conclude, given the species longevity, its sensitivity to climate as well as the availability of sample material throughout the Australian Alps, that P. lawrencei holds a hitherto unrealised potential for climate reconstruction in south-east Australia. Further dendrochronological investigation of the species is currently underway throughout the Australian Alps to exploit this potential.
Small, local populations of the endangered Mountain Pygmy-possum
Burramys parvus occur on the Koskiuszko Plateau, in south-eastern Australia, including within ski resort lease areas. Between 1986 and ...1998 four populations, two within and two outside ski areas, were studied to assess their dynamics and to determine if ski resort management was likely to impact on the conservation of the species. One of the resorts, at Mount Blue Cow, was constructed as the study commenced. Analysis of the 11–12 year data sets showed strong site differences in sex ratios, annual and winter survival rates, site persistence, recruitment and spring weights. Regional trends, attributed to exogenous climatic factors, were evident but population fluctuations were generally uncorrelated and strong site by year interactions occurred for most demographic parameters. Despite this, strong density dependence on all sites in recruitment and to a lesser extent annual survival suggest
B. parvus is habitat limited and that social factors drive demographics in these populations. There was no evidence that the ski resort at Mount Blue Cow had any significant impacts above natural yearly variation in demographics in the first 11 years of its operation. However, the highest quality sites, in terms of population size and stability, were those within the two ski resort lease areas. Further, the asynchronous population dynamics, a small amount of migration between habitat patches, differences in site quality and heterogeneity in site structure and aspect, which may contribute to population persistence, indicates that a metapopulation approach to conservation of
B. parvus on the Kosciuszko plateau is warranted. This has important implications for long-term conservation of
B. parvus in the ski resort areas. These sites will require careful monitoring and management to ensure the continued viability of the resident and surrounding
B. parvus populations.
The fossil record provides important information about changes in species diversity, distribution, habitat and abundance through time. As we understand more about these changes, it becomes possible ...to envisage a wider range of options for translocations in a world where sustainability of habitats is under increasing threat. The Critically Endangered alpine/subalpine mountain pygmy-possum,
(Marsupialia, Burramyidae), is threatened by global heating. Using conventional strategies, there would be no viable pathway for stopping this iconic marsupial from becoming extinct. The fossil record, however, has inspired an innovative strategy for saving this species. This lineage has been represented over 25 Myr by a series of species always inhabiting lowland, wet forest palaeocommunities. These fossil deposits have been found in what is now the Tirari Desert, South Australia (24 Ma), savannah woodlands of the Riversleigh World Heritage Area, Queensland (approx. 24-15 Ma) and savannah grasslands of Hamilton, Victoria (approx. 4 Ma). This palaeoecological record has led to the proposal overviewed here to construct a lowland breeding facility with the goal of monitoring the outcome of introducing this possum back into the pre-Quaternary core habitat for the lineage. If this project succeeds, similar approaches could be considered for other climate-change-threatened Australian species such as the southern corroboree frog (
) and the western swamp tortoise (
). This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'
•We measured the thermal buffering capacity (TBC) of boulder fields.•We found remarkable seasonal and spatial variations in TBCs of boulder fields.•We investigated the factors driving TBC using ...multilevel regression modeling.•Vegetation cover and elevation affected the TBC at the point level.•Slope aspect and inclination affected the TBC at the cluster level.
Identifying and protecting microhabitats with conservation value is becoming a high priority for conservationists under projected climate change. Information on the buffering effects of microhabitats and its major drivers is a prerequisite to implementing effective conservation. We collected hourly temperature data from 70 alpine–subalpine sites nested within 9 boulder field clusters in an area measuring approximately 60km×30km in New South Wales, Australia, over a period of more than 2years. We studied the thermal buffering effect of the boulder fields and investigated the factors driving the effect using multilevel (i.e., sampling points nested within boulder field clusters) regression modeling. We found remarkable seasonal and spatial variations in the thermal buffering effect of boulder fields. Boulder fields buffered the surface temperature maxima by 2.91°C at a depth of 50cm and 4.39°C at a depth of 100cm, while they buffered the surface temperature minima by 0.54°C at the depth of 50cm and 1.36°C at the depth of 100cm, with temperature range reduced by 3.45°C and 6.48°C in warmer period and by 1.23°C and 2.05°C in colder period at two depths. We defined thermal buffering in temperature ranges as the thermal buffering capacity (TBC) as an exemplar for multilevel modeling. We found that vegetation cover and elevation affected the TBC at the point level, whereas the aspect and inclination of slopes affected the TBC at the cluster level. These findings are instructive for the protection of habitats, as high priority should be given to those habitats that offer effective TBC. Furthermore, the environmental factors identified to be driving TBC provide important input to the management of species habitats.
The Australian alpine region harbours a wide range of species, many of which are endemic and of high conservation value. Among these species, the endangered mountain pygmy‐possum, Burramys parvus, is ...of particular interest because this specialized marsupial is highly sensitive to extreme temperatures. The selection of microhabitats by B. parvus is a critical but poorly understood element of its biological characteristics. To understand the microhabitat preferences of B. parvus, we performed detailed investigations of the thermal properties of alpine boulder fields. The selection of a preferred microclimate was demonstrated by comparing temperatures and environmental conditions in preferred and non‐preferred boulder fields. The variability of the daily temperature depended on the depth at which measurements were made within the boulder fields. Temperatures were more stable as depth increased. The results suggest that B. parvus prefers to occupy deep boulder fields at high elevations with good rock structure (small rock and cavity size with multiple layers) and long snow duration because these boulder fields can provide a favourable microclimate. At 1 m depth, the maximum temperatures in the hottest part of the year were 1.27°C cooler in preferred compared to non‐preferred boulder fields. In the coldest part of the year, immediately following the melting of persistent snow cover, the minimum temperatures at a depth of 1 m were 1.67°C warmer in preferred compared to non‐preferred boulder fields. On average, the snow duration was 27 days greater in the boulder fields preferred by B. parvus than in non‐preferred boulder fields. Our results emphasize the value of boulder field microhabitats as thermal refuges for small mammals in rocky habitats within alpine environments in the light of continuing habitat loss and climate change.
The Burramys Project Archer, Michael; Bates, Hayley; Hand, Suzanne J. ...
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
12/2019, Letnik:
374, Številka:
1788
Journal Article
Recenzirano
The fossil record provides important information about changes in species diversity, distribution, habitat and abundance through time. As we understand more about these changes, it becomes possible ...to envisage a wider range of options for translocations in a world where sustainability of habitats is under increasing threat. The Critically Endangered alpine/subalpine mountain pygmy-possum, Burramys parvus (Marsupialia, Burramyidae), is threatened by global heating. Using conventional strategies, there would be no viable pathway for stopping this iconic marsupial from becoming extinct. The fossil record, however, has inspired an innovative strategy for saving this species. This lineage has been represented over 25 Myr by a series of species always inhabiting lowland, wet forest palaeocommunities. These fossil deposits have been found in what is now the Tirari Desert, South Australia (24 Ma), savannah woodlands of the Riversleigh World Heritage Area, Queensland (approx. 24–15 Ma) and savannah grasslands of Hamilton, Victoria (approx. 4 Ma). This palaeoecological record has led to the proposal overviewed here to construct a lowland breeding facility with the goal of monitoring the outcome of introducing this possum back into the pre-Quaternary core habitat for the lineage. If this project succeeds, similar approaches could be considered for other climate-change-threatened Australian species such as the southern corroboree frog (Pseudophryne corroboree) and the western swamp tortoise (Pseudemydura umbrina).
This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'
1. A method of validating stochastic models of population viability is proposed, based on assessing the mean and variance of the predicted population size. 2. The method is illustrated with a model ...of the population dynamics of the mountain pygmy-possum (Burramys parvus Broom 1895), based on annual census data collected from a single population in the Snowy Mountains of New South Walcs, Australia between 1986 and 1997. The model incorporates density-dependence in survivorship and recruitment, and demographic and environmental stochasticity. 3. The model appeared to make reasonable predictions for the three populations that were used for validation, provided the equilibrium population size was estimated accurately. This may require that differences in habitat quality between populations be taken into account. 4. Following validation, the model was given new parameters using the additional data from the three populations, and the risk of population decline within the next 100 years was assessed. Although populations as small as 15 females are predicted to be relatively safe from extinction caused by stochastic processes, B. parvus appears vulnerable to loss of habitat and reductions in the population growth rate. 5. The approach used in this paper is one of few attempts to validate a model of population viability using field data, and demonstrates that some aspects of stochastic population models can be tested.
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