The mountain pygmy-possum (Burramys parvus) is a rare marsupial (approximately 2300 individuals) with a restricted distribution (10 km*3 confined to isolated patches of heath in the Australian Alps that are vulnerable to clearing and modification for ski-run development. In Mt Kosciusko National Park the diet of Burramys averaged 71% arthropods, 27% seeds and berries, and 2% other material. The diversity of arthropod prey was low and dominated by a single species, Agrotis infusa (the Bogong moth). The diversity of seed and berry intake was high (8 species) and dominated by the seed and fruit of Podocarpus lawrencei (8%) and fruit of Leucopogon montanus. The relative proportion of arthropod to seed and berry in the diet changed significantly with sex, age, reproductive state, body weight, season, elevation and habitat (Podocarpus lawrencei cover, boulder cover and moth abundance). Females had a higher intake of arthropod than males in all seasons and locations. This result is consistent with their higher protein requirement for reproduction and the need to ensure that young grow rapidly enough to gain sufficient weight to survive their first winter in hibernation. Patterns of spatial and seasonal variation in food availability explain the unique patterns of sexual segregation and daily and/or seasonal migration exhibited by Burramys. Nightly or seasonal movement is necessary to optimise exploitation of Bogong moths on high-elevation peaks in summer and seeds and berries in lower-elevation heaths during late summer and early autumn. These results signify the importance of protecting migration corridors along boulder screes, between low- and high-elevation habitats, from destruction or modification during ski-run development.
The smoky mouse, Pseudomys fumeus, is an endangered rodent for which ecological information is lacking across much of its range. This paper provides the first detailed study of the local diet and habitat preference of P. fumeus since 1980, conducted on the recently discovered Nullica population in New South Wales. Diet and trap-revealed movements were examined in conjunction with 18 characteristics of habitat to determine the factors influencing habitat choice. Multiple logistic regression of habitat variables and capture locations revealed a floristically determined preference for heath habitat characterised by Epacris impressa, Monotoca scoparia, Leptospermum trinervium, Xanthorrhoea spp. and a variety of legumes. Hypogeal fungi and seeds were the most common food items in the diet of P. fumeus. Fungi were most abundant in winter diet, while seeds and fruit became dominant in late spring and summer. The spring and summer preference for ridge-top heath habitats observed in this study is probably the result of this dietary preference. Resident females constituted 71% of the population in early spring. However, there was a severe decline in numbers of female mice during early spring, and resident males also disappeared from the population. Causes of the decline were unclear. Five of eleven males captured during this study were transient, while no transient females were caught. The sudden decline in the study population, combined with the patchy distribution of suitable habitat and high level of male transience, suggests that P. fumeus form a metapopulation in the Nullica region.
The endangered Mountain Pygmy-possum Burramys parvus is an alpine-subalpine specialist and the only Australian mammal entirely restricted to areas above the winter snowline. There are three geographically isolated populations of B. parvus: Kosciuszko National Park (South Ramshead - Cabramurra) in New South Wales, and Mt Bogong - Mt Higginbotham and Mt Buller in Victoria. Populations have shown signs of rapid decline over the last 15 years. The duration of snow cover and time of snow melt appear to be linked to the survival rate of the Mountain Pygmy-possum which is under severe threat from climate change. Here we discuss its life history, extinction threats and the potential value of the fossil record in identifying conservation options for the Mountain Pygmy-possum. Also presented is a proposal to establish a breeding facility for the rapidly declining Kosciuszko population in New South Wales. This breeding facility would firstly provide a safety net for unanticipated disasters in the alpine and subalpine zone that might occur in the short term. Secondly, the facility would provide an opportunity to address concerns that climate change will eventually transform the subalpine-alpine zone, making it unsuitable for further survival of B. parvus populations. To address this concern, we propose breeding surplus individuals that could be experimentally acclimatised for release into alternate environments.
Abstract The A ustralian 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, B urramys 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.
Summary The Mountain Pygmy‐possum Burramys parvus has been listed as an endangered species across its range in the alpine and subalpine areas of New South Wales and Victoria. This study reports on the occurrence of the species in an artificial habitat, spoil dumps that were created in the 1950s as a result of the construction of underground tunnels associated with the Snowy Hydro‐electric Scheme. Thirty‐four B. parvus were captured in 1065 trapnights on spoil dumps in Happy Jacks Creek valley, in northern Kosciuszko National Park in October and November 2011. In January 2012, 22 individuals were captured in 360 trapnights on a spoil dump at Guthega Adit Camp in southern Kosciuszko National Park. Seven radio‐collared individuals tracked in Happy Jacks Creek valley resulted in the location of 5 day shelters in spoil dump habitat, including individuals that were originally trapped in nearby natural habitat. This study indicates that there may be opportunity to create further artificial habitat on sites not currently used by this highly restricted species.
We compared characteristics of successful gadwall (Anas strepera) nests and those destroyed by mammalian predators (i.e., striped skunks [Mephitis mephitis]). Lateral cover density, understory cover height, species richness, vegetative penetrability, and patch size were significant determinants of the fate of a nest. Nest success was also influenced by 3 nonvegetative variables: minimum distance to water, dike width, and nest initiation date. Predation rates on nests differed (P 1.0 m), dense biennial and perennial weeds such as thistle (Cirsium arvense), stinging nettle (Urtica dioica), and teasel (Dipsacus spp.), and lacked well-developed understory (ground vegetation). The proportional occurrences of habitats A, B, and C were 33, 42, and 25%, respectively. Beginning in late May, we located nests by flushing females with a slow moving truck and occasional bursts of the truck's horn. This procedure was effective because all nests occurred within 10 m of the dike road. Density of waterfowl nests on the study area was determined by a complete enumeration verified by intensive ground searches in each area. Data recorded for each nest included species, number of eggs, stage of development (Weller 1956), and habitat. Pin flags were placed perpendicular to each nest at the edge of the road. One hundred seventy artificial nests were placed at random distances perpendicular to the dike road at regular intervals along the dike. They consisted of 2 chicken eggs the size of gadwall eggs placed in a shallow, excavated bowl. The same procedures employed for natural nests were used for artificial nests. Because predation rates for natural nests This content downloaded from 157.55.39.186 on Tue, 12 Apr 2016 09:03:55 UTC All use subject to http://about.jstor.org/terms J. Wildl. Manage. 53(1):1989 HABITAT NEST PREDATION * Crabtree et al. 131
Abstract A population of mountain pygmy‐possums Burramys parvus was studied at the Mount Blue Cow ski resort in Kosciuszko National Park between 1986 and 1989. Forty‐eight individuals were radiotracked during the snow‐free months and 21 individuals were tracked during winter over the 3 years of study. Trapping and radiotracking showed that the density, population structure, movements and home range sizes of B. parvus on Mount Blue Cow were strongly correlated with elevation and changed with the season. Female densities were greatest in habitats characterized by deep boulderfields, at high elevations with an abundance of Bogong moths. Males visited the areas where females were located to breed in November–December and then by February, the majority migrated to lower elevations or north and westerly aspects. Females that nested at lower elevations also visited high‐elevation habitats to access the high concentrations of Bogong moths, which were the main food source in summer. A high proportion of the juvenile males and some juvenile females dispersed to lower elevations in March and April. The resulting sexual segregation during autumn and winter may be a result of female aggression or scramble competition, but is also explainable by differences in energy requirements, seed availability and hibernation strategies between the sexes. The extraordinarily large nightly and seasonal movements between habitat patches of up to 2 km for females and 3 km for males, sexual segregation and the use of different hibernation sites have important implications for the management of this species. These include the need for movement and dispersal corridors and the conservation of boulder‐heath habitats outside the main boulderfields.
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