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1
Sale, M. G., F. J. L. Kraaijeveld-Smit, and J. P. Y. Arnould. "Multiple paternity in the swamp antechinus (Antechinus minimus)." Australian Mammalogy 35, no. 2 (2013): 227. http://dx.doi.org/10.1071/am12039.
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Multiple paternity within litters or broods occurs across a variety of taxa. In the present study, paternity patterns in the swamp antechinus (Antechinus minimus), a small carnivorous marsupial, were investigated using genetic analyses. Microsatellite data confirmed that, of 10 litters sampled from two habitats, a minimum of eight litters were sired by more than one male. Mating with multiple males may enable female swamp antechinuses to increase offspring viability and to ensure fertilisation.
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Baker, Andrew, and Steve Van Dyck. "Taxonomy and redescription of the swamp Antechinus, Antechinus minimus (E. Geoffroy) (Marsupialia: Dasyuridae)." Memoirs of the Queensland Museum - Nature 59 (July 31, 2015): 127–70. http://dx.doi.org/10.17082/j.2204-1478.59.2015.2014-11.
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Sale, Michael G., Barbara A. Wilson, and John P. Y. Arnould. "Factors influencing population dynamics in island and mainland populations of the swamp antechinus (Antechinus minimus)." Australian Journal of Zoology 56, no. 3 (2008): 187. http://dx.doi.org/10.1071/zo08076.
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Simultaneously analysing demographic processes of small mammals living in different ecological contexts may help to understand mechanisms that influence the growth and decline of these populations. The size and demography of swamp antechinus (Antechinus minimus) populations located in a coastal mainland habitat and on a small offshore island in south-eastern Australia were investigated. Large demographic differences occurred between the two ecosystems, with the island population density often 100 times greater than that on the mainland. The swamp antechinus in the mainland habitat was influenced by extrinsic climatic forces, with juvenile recruitment, individual body mass and overall population size being affected by rainfall, a factor likely to influence food availability for the species. However, the island population did not appear to be affected by drought to the same degree where allochthonous marine nutrient inputs may have offset any drought-induced reduction in primary production. Significantly greater juvenile recruitment in the island habitats combined with restricted emigration and potentially reduced predation and interspecific competition are likely to be responsible for the high population densities on the island. Although island populations appear robust, future conservation efforts should focus on mainland populations given the genetic deficiencies in the island populations.
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Sale, M. G., S. J. Ward, and J. P. Y. Arnould. "Aspects of the ecology of swamp antechinus (Antechinus minimus maritimus) on a Bass Strait island." Wildlife Research 33, no. 3 (2006): 215. http://dx.doi.org/10.1071/wr05051.
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The swamp antechinus (Antechinus minimus maritimus) is a small insectivorous marsupial inhabiting closed heath and tussock grassland in south-eastern Australia. The species is considered ‘Near Threatened’ on the Australian mainland. Populations persist on coastal islands off Wilsons Promontory, but their current status is unknown. This study investigated the density, diet and reproduction of the swamp antechinus on Kanowna Island. Data were collected by live trapping in different vegetation types during four trips between August 2003 and January 2004. Higher animal densities (47–129 ha–1) were found for Kanowna Island than for previously studied mainland populations (1–18 ha–1). Examination of scats showed that this species eats a wide variety of prey types, with moth larvae a major dietary component, particularly during the breeding season. Births were estimated to have occurred between 28 June and 8 August, which is a longer period than reported for other populations of this species. Factors including reduced predation, restricted dispersal and increased food availability may be responsible for supporting this dense population.
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Wilson, BA. "Reproduction in the Female Dasyurid Antechinus-Minimus-Maritimus (Marsupialia, Dasyuridae)." Australian Journal of Zoology 34, no. 2 (1986): 189. http://dx.doi.org/10.1071/zo9860189.
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Reproduction in female Antechinus minimus maritimus was investigated in the field and laboratory. Field data were obtained from a mark-recapture study. A laboratory colony was maintained to investigate the oestrous pattern, length of gestation and development of pouch young. Breeding occurred in winter with births in July or August. Gestation (mean � SD) was 30.6 � l.5 days for animals mated in the laboratory. Epithelial cells were present in the urine for 34.8 � 8.3 days, a lengthy period compared to A. stuartii (19.3 � 4.4 days). Ovaries from females before the breeding season contained small developing follicles. During the breeding season Graafian follicles (4-8 per ovary) or corpora lutea (4-13 per ovary) were found. Reproduction in A. m. maritimus females is similar to that described previously in other Antechinus.
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Allison, Louise M., Lesley A. Gibson, and John G. Aberton. "Dietary strategy of the swamp antechinus (Antechinus minimus maritimus) (Marsupialia:Dasyuridae) in coastal and inland heathland habitats." Wildlife Research 33, no. 1 (2006): 67. http://dx.doi.org/10.1071/wr05038.
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In the coastal heathlands of southern Victoria, populations of a rare dasyurid, the swamp antechinus (Antechinus minimus maritimus), are restricted to small and disjunct patches of suitable habitat. Although characteristics of their preferred habitat in terms of vegetation structure and composition have been described, little is known of their diet preferences. Diet and food availability of the species was examined at two coastal and two inland sites, during winter and spring by way of faecal analyses and pitfall trapping. Only minor differences in diet were observed between the coastal and inland habitats and this was consistent across season. There was, however, variation in food availability between the two habitat types, with generally higher frequencies of invertebrates occurring within the inland than in the coastal habitat during spring. Even so, when diet was directly compared with food availability, the differences observed within individual categories within each season were similar in magnitude and direction for both habitats, suggesting that inland and coastal populations of the swamp antechinus have similar dietary strategies. Insect larvae, Diplopoda and Coleoptera appeared to be favoured dietary items being almost consistently over-represented in the diet compared to their availability, whereas Collembola, Amphipoda, Dermaptera and Formicidae were avoided as they were never consumed in proportion to their availability. Although dietary preferences were evident, there was no clear selection of any one particular prey item, and so the swamp antechinus was considered a dietary generalist. Also, as the species sampled from most of the range of prey items available to them, it fits the qualitative criterion of opportunism. The generalist strategy of the swamp antechinus is likely to be advantageous in an environment subject to disturbance.
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Wilson, B. A., J. G. Aberton, and T. Reichl. "Effects of fragmented habitat and fire on the distribution and ecology of the swamp antechinus (Antechinus minimus maritimus) in the eastern Otways, Victoria." Wildlife Research 28, no. 5 (2001): 527. http://dx.doi.org/10.1071/wr00016.
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This study investigated the distribution, habitat and population dynamics of the swamp antechinus (Antechinus minimus maritimus) in the eastern Otway Ranges. The species has a restricted, disjunct distribution and has been recorded at 25 sites between 1969 and 1999. All sites were located within 7 km of the coast, occurred at altitudes up to 80 m above sea level and within 10 m of a gully. Analysis of landscape site variables identified sun index as being significant in determination of the probability of occurrence of A. minimus. The presence of A. minimus is negatively associated with sun index, occuring at sites that have a southerly aspect and gentle slope. A. minimus was located in a range of structural vegetation including Open Forest, Low Woodland, Shrubland and Hummock Grassland and a number of floristic groups, some characterised by high frequencies of sclerophyll shrubs, others by high frequencies of Pteridium esculentum, hummock grasses and herbaceous species. A. minimus occurs in fragmented, small populations with maximum population densities of 1.1–18 ha–1. Populations at inland sites became extinct after the 1983 wildfire which burnt 41 000 ha. These sites have not been recolonised since, while on the coast the species did not re-establish until 1993–97. One population that is restricted to a narrow coastal strip of habitat is characterised by high levels of transient animals. The species is subject to extinction in the region due to habitat fragmentation, coastal developments and fire. Management actions to secure the present populations and ensure long-term survival of the species in the area are required and include implementation of appropriate fire regimes, prevention of habitat fragmentation, revegetation of habitat, and establishment of corridor habitat.
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Magnusdottir, Rannveig, Barbara A. Wilson, and Pall Hersteinsson. "Dispersal and the influence of rainfall on a population of the carnivorous marsupial swamp antechinus (Antechinus minimus maritimus)." Wildlife Research 35, no. 5 (2008): 446. http://dx.doi.org/10.1071/wr06156.
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Although there is evidence that recent climatic changes have had significant impacts on a wide range of species in the Northern Hemisphere, the influence of climate change, particularly drought, on Australian native small mammal species is poorly understood. In this study we investigated dispersal patterns and the influence of rainfall on the swamp antechinus (Antechinus minimus maritimus). Peak abundance occurred after the highest total annual rainfall for two decades, in 2001. A year later the population had declined to 10% of the peak. Birth dates appeared to occur three weeks earlier following a year of high rainfall. The dispersal of nine litters of pouch young (n = 62) was assessed following two breeding seasons. Young males remained on the natal site until December–January and dispersed before the breeding season. New males entered the population between January and June. More than 50% of females were residents and remained on the site to breed; the remaining females were trapped only once. After the male die-off the movements of pregnant females increased and they appeared to expand their home ranges. A. minimus exhibits philopatry of females and dispersal of males, as observed in other Antechinus species but dispersal occurs 2–3 months after weaning. This contrasts with juveniles of other Antechinus species that disperse abruptly after weaning. This study provides evidence that precipitation does have a major effect on the abundance of dasyurid species, making them vulnerable to drought and local or regional extinctions, particularly in areas of fragmented habitat and drying climates.
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Sale, M. G., and J. P. Y. Arnould. "Inflated population density of island antechinus: a case of allochthonous marine inputs leading to increased food availability?" Australian Journal of Zoology 60, no. 5 (2012): 343. http://dx.doi.org/10.1071/zo12073.
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Resource availability and other processes that affect maintenance, growth and decline of animal populations are central to ecology and conservation. This study quantified features indicative of population fitness and the availability of food resources for island and mainland populations of an insectivorous marsupial, the swamp antechinus (Antechinus minimus). The aim of the study was to test the hypothesis that colonial seabirds increase productivity of island habitats, ultimately providing greater food resources. The study found that antechinus biomass density was 4–13 times greater on the island site compared with the mainland site and was associated with higher recapture rates, suggesting that more individuals were surviving on the island during spring and summer months. An index of antechinus food availability (abundance and biomass of invertebrates) was also higher on the island site. Island antechinus also accessed marine food subsidies, in the form of seabird carrion, during the energetically demanding post-weaning growth period in spring and summer. Furthermore, based on soil nutrient and stable isotope analyses, there was strong evidence of nutrient enrichment from marine sources in the island ecosystem, commonly linked to increased productivity. Therefore, greater antechinus biomass and abundance on offshore islands are likely to be, in part, due to greater survival caused by higher availability of food resources.
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Sale, M. G., F. J. L. Kraaijeveld-Smit, and J. P. Y. Arnould. "Natal dispersal and social organization of the swamp antechinus (Antechinus minimus) in a high-density island population." Canadian Journal of Zoology 87, no. 3 (March 2009): 262–72. http://dx.doi.org/10.1139/z09-012.
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Radiotelemetry, mark–recapture trapping, and microsatellite analysis of genetic variation among three subpopulations were used to investigate the natal dispersal patterns, genetic structure, and social organization within a high-density island population of an insectivorous marsupial, the swamp antechinus ( Antechinus minimus (É. Geoffroy Saint-Hilaire, 1803)). Both demographic and genetic data indicated a high degree of philopatry for both sexes. Associated with high philopatry is low gene flow, often leading to high population genetic structuring. However, there was only weak evidence to support this; allele frequencies and genotype composition of one population tended to be different from the other two. Interestingly, timing of breeding of this subpopulation was delayed compared with the other two subpopulations. The philopatry of both sexes and the apparent lack of kin avoidance behaviour could lead to inbreeding. However, no apparent inbreeding effects were observed and offspring survival was high compared with mainland populations. The fact that male home-range size increased during the breeding season, overlapping with several females, and single females were found nesting with different males at the time of mating (and vice versa) indicates a promiscuous mating system. Potentially, this may reduce inbreeding to some extent. Alternatively, inbreeding may not be purposefully avoided, potentially leading to purging of detrimental alleles, thereby reducing their damaging effects on inbreeding.
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Gibson, Lesley A., Barbara A. Wilson, David M. Cahill, and John Hill. "Modelling habitat suitability of the swamp antechinus (Antechinus minimus maritimus) in the coastal heathlands of southern Victoria, Australia." Biological Conservation 117, no. 2 (May 2004): 143–50. http://dx.doi.org/10.1016/s0006-3207(03)00288-x.
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Wilson, BA, AR Bourne, and RE Jessop. "Ecology of Small Mammals in Coastal Heathland at Anglesea, Victoria." Wildlife Research 13, no. 3 (1986): 397. http://dx.doi.org/10.1071/wr9860397.
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Aspects of ecology and reproduction of small mammals in a heathland community near Anglesea were investigated in the field by means of mark-recapture trapping. Population size, animal movements and reproductive state were estimated. The floristic and structural habitat preferences were also determined. The most common species were Antechinus stuartii, A. minimus maritimus, Sminthopsis leucopus, Rattus fuscipes assimilis and R. lutreolus. For Antechinus the populations were maximal throughout February-June (A. stuartii) and December-June (A. minimus) inclusive. A marked decline in numbers of Antechinus during late winter and early spring was associated with the total loss of males from the population. The maximal numbers of animals (per hectare) were 21 (A. stuartii), 14 (A. m. maritimus), 14 (R. f. assimilis) 7 (R. lutreolus), and 8 (S. leucopus). Young were born to A. m. maritimus during August, and 1 month later to A. stuartii. R. f. assimilis bred during late winter and spring, and S. leucopus from September to November. None of the species showed an overall preference for any floristic or structural vegetation type. This study confirms male 'die-off' in A. m. maritimus. The data also indicate that the difference in breeding times of A. m. maritimus between Anglesea and Dartmoor, Vic., is due to climatic or habitat differences rather than to sympatry with A. stuartii.
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Moro, D. "The Distribution of small mammal species in relation to heath vegetation near Cape Otway, Victoria." Wildlife Research 18, no. 5 (1991): 605. http://dx.doi.org/10.1071/wr9910605.
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A trapping study of small mammals within heath communities near Cape Otway was conducted during April-August 1989. The purpose was to describe the distribution patterns of several small mammals in relation to a floristic and structural description of the vegetation. Two species of rodent (Rattus lutreolus, R. fuscipes), two species of dasyurid (Antechinus stuartii, A. minimus) and one species of bandicoot (Isoodon obesulus) were trapped frequently enough for statistical analysis. A. stuartii was trapped significantly more often in the Heathy Open-forest than in the Closed Heath community, in contrast to A. minimus and R. lutreolus, which were captured significantly more often in Closed Heath. There was no significant difference in the distributions of R. fuscipes and I. obesulus between communities. Within the Closed Heath community only R. fuscipes displayed significant distribution patterns between sub-communities. In the Heathy Open-forest the distribution of captures among sub-communities varied significantly for both species of Antechinus and for R. lutreolus. Floristic and structural cues, as well as ground cover, were associated with the spatial distribution of dasyurid and rodent species. Bandicoot dispersion was associated only with vertical vegetation diversity. The importance of interspecific avoidance in contributing to the observed distribution patterns of both dasyurid and rat species cannot be dismissed.
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Wilson, Barbara A., Lily Zhuang-Griffin, and Mark J. Garkaklis. "Decline of the dasyurid marsupial Antechinus minimus maritimus in south-east Australia: implications for recovery and management under a drying climate." Australian Journal of Zoology 65, no. 4 (2017): 203. http://dx.doi.org/10.1071/zo17041.
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Our understanding of recent extinctions and declines of Australian mammals is poor, particularly where there is a paucity of data to quantify change. The swamp antechinus (A. m. maritimus) has a fragmented, coastal distribution in south-east Australia. Although long-term studies (1975–2007) of this vulnerable species were conducted in the eastern Otways, its current status was unclear. We assessed the success of live trapping and camera trapping (2013–17) at 42 sites, 19 where the species was trapped previously. Between 2013 and 2015 A. m. maritimus was recorded at only 6 sites (n = 8), but at none in 2016–17. Assessment of long-term changes found that high-density populations occurred after above-average rainfall, and both low- and high-density populations collapsed after wildfire, after low rainfall, and in fragmented habitat. The species may now be restricted to very small populations in refuges such as coastal dunes, and predicted low rainfall and increased burning frequency pose major threats to the species’ survival. Recovery is unlikely without targeted management, including predator control and protection from inappropriate fire regimes and habitat fragmentation. If similar declines have been experienced across the species’ range, prevention of extinction of the species will require similar management strategies.
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Smith, Geoffrey C., Kath Means, and Sue Churchill. "Aspects of the ecology of the Atherton antechinus (Antechinus godmani) living in sympatry with the rusty antechinus (A. adustus) in the Wet Tropics, Queensland – a trapping and radio-tracking study." Australian Mammalogy 40, no. 1 (2018): 16. http://dx.doi.org/10.1071/am16050.
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The ecology of the geographically restricted Atherton antechinus (Antechinus godmani) is poorly known. This trapping and radio-tracking study provides historical baseline information on its ecology. The Atherton antechinus foraged primarily at night in deep leaf litter and rotting logs. The sympatric, smaller rusty antechinus (A. adustus) was arboreal and active both day and night, suggesting resource partitioning between species. The diet of the Atherton antechinus included a significant component of beetles, centipedes, spiders, cockroaches, crickets, and ants; minor items included a frog and a skink. Declines in male condition of both antechinus species occurred in June–July. Free-living young of the rusty and the Atherton antechinus were first trapped in November and January, respectively. Minimum convex polygon home ranges for the Atherton antechinus were 2.5–5.8 ha for males and 3.6 ha for a female. Multiple nest sites were used by individual Atherton antechinuses with simultaneous sharing of nests observed only between sexes. A home range of a single female was overlapped by the home ranges of numerous males. The Atherton antechinus prefers contiguous areas of wet tropical upland rainforest with old-growth characteristics, including large old trees for nest sites, fallen woody debris and deep leaf litter for foraging. The impacts of climate change could be devastating.
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Twyford, K. L. "Habitat Relationships of Small Mammals at Port Campbell National Park, Victoria." Australian Mammalogy 20, no. 1 (1998): 89. http://dx.doi.org/10.1071/am97089.
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Habitat relationships of six species of small mammals was investigated in eight vegetation communities at Port Campbell National Park, Victoria. The dispersion of 317 trap captures over 10 months was used to assess the relationships of small mammals with different vegetation communities. Rattus fuscipes showed a strong affinity for dense, structurally complex vegetation, particularly a disused softwood plantation and to a lesser extent a closed-heath/low open-forest community. Captures of Rattus lutreolus were most frequent in the wetter communities which provided adequate cover, particularly the swamp community. A possible relationship between captures of this species and the abundance of sedge food resources is suggested. Antechinus swainsonii was captured in greatest numbers in tussock-grassland/low open-shrubland where dense ground cover was present. However, areas with dense mid-storey cover which were considered to be favourable habitat supported few individuals. Sminthopsis leucopus, although captured at low rates in only two communities, favoured more open vegetation than both A. swainsonii and A. minimus. The later species was captured rarely, but exclusively in open-heath, although more favourable habitat appeared to be present elsewhere in the Park. The low abundance of Mus musculus was attributed to a lack of habitat available at an early successional stage. A mammal species list for the Park of 15 species has been compiled based on trapping, incidental observations and indirect traces. Key areas for conservation of small mammals within the Park are identified.
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Hume, Taylor, Fritz Geiser, Shannon E. Currie, Gerhard Körtner, and Clare Stawski. "Responding to the weather: energy budgeting by a small mammal in the wild." Current Zoology 66, no. 1 (May 17, 2019): 15–20. http://dx.doi.org/10.1093/cz/zoz023.
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Abstract Energy conservation is paramount for small mammals because of their small size, large surface area to volume ratio, and the resultant high heat loss to the environment. To survive on limited food resources and to fuel their expensive metabolism during activity, many small mammals employ daily torpor to reduce energy expenditure during the rest phase. We hypothesized that a small terrestrial semelparous marsupial, the brown antechinus Antechinus stuartii, would maximize activity when foraging conditions were favorable to gain fat reserves before their intense breeding period, but would increase torpor use when conditions were poor to conserve these fat reserves. Female antechinus were trapped and implanted with small temperature-sensitive radio transmitters to record body temperature and to quantify torpor expression and activity patterns in the wild. Most antechinus used torpor at least once per day over the entire study period. Total daily torpor use increased and mean daily body temperature decreased significantly with a reduction in minimum ambient temperature. Interestingly, antechinus employed less torpor on days with more rain and decreasing barometric pressure. In contrast to torpor expression, activity was directly related to ambient temperature and inversely related to barometric pressure. Our results reveal that antechinus use a flexible combination of physiology and behavior that can be adjusted to manage their energy budget according to weather variables.
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Parrott, Marissa L., Simon J. Ward, and Peter D. Temple-Smith. "Genetic similarity, not male size, influences female mate choice in the agile antechinus (Antechinus agilis)." Australian Journal of Zoology 54, no. 5 (2006): 319. http://dx.doi.org/10.1071/zo06030.
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Our research investigates the effects of genetic relatedness between mates and male size on female mate choice in the agile antechinus (Antechinus agilis). Females were provided with a simultaneous choice between one large and one small male, with a minimum 5 g (~20% of male weight) difference between males, in specially designed mate-choice enclosures. Genetic relatedness between males and females was determined using highly polymorphic, species-specific, microsatellite markers. Male size did not influence mate choice, with approximately equal numbers of large and small males chosen. Females chose males that were more genetically dissimilar to themselves significantly more times and showed significantly more sexual and non-exploratory behaviours near the genetically dissimilar males. The results show that, when free female mate choice is possible, female agile antechinus choose males on the basis of genetic relatedness, rather than male size.
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Sanecki, Glenn M., Ken Green, Helen Wood, David Lindenmayer, and Karen L. Sanecki. "The influence of snow cover on home range and activity of the bush-rat (Rattus fuscipes) and the dusky antechinus (Antechinus swainsonii)." Wildlife Research 33, no. 6 (2006): 489. http://dx.doi.org/10.1071/wr05012.
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Radio-telemetry was used to investigate changes in home-range sizes and activity patterns of Rattus fuscipes and Antechinus swainsonii in a subalpine heathland at Perisher Creek, Kosciuszko National Park, southern New South Wales, in response to the accumulation of snow during the winter. We estimated home-range area for each animal during the autumn and winter using two methods, minimum convex polygon and 95% and 50% utilisation contours using the kernel method. With both methods, the home ranges of R. fuscipes and A. swainsonii were significantly smaller (P < 0.001) during the winter than in the autumn. In winter, both species were restricted to areas of dense wet heath close to the main drainage line. R. fuscipes showed signs of social interaction during both seasons, as indicated by location fixes and gnawing damage to radio-collars, in contrast to A. swainsonii, which appeared to remain solitary. In winter, R. fuscipes apparently nested at a single location, whereas during autumn it appeared to use several nest sites. There was no significant change in daily activity patterns between autumn and winter in either species. R. fuscipes remained primarily nocturnal during both prenival and nival periods whereas A. swainsonii continued to be active throughout the diel cycle, although there was a slight shift in its peak activity time from around sunset in autumn to early morning in winter.
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Withers, KW, and AJ Hulbert. "Cold-Acclimation in the Marsupial Antechinus-Stuartii - Thyroid-Function and Metabolic-Rate." Australian Journal of Zoology 36, no. 4 (1988): 421. http://dx.doi.org/10.1071/zo9880421.
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Metabolic rate and food energy intake of Antechinus stuartii at 5�C and 25�C, and thyroid iodine secretion rate of A. stuartii and Mus musculus were compared after acclimation to 5�C or 25�C for 6-8 weeks. Acclimation to cold increased minimum metabolic rate of A. stuartii at 25�C but not at 5�C and had no significant influence on daily metabolic rate and food energy intake at 5�C or at 25�C. Thyroid secretion rate of A. stuartii was 0.47�0.07 �g I day-' and 0.15�0.02 �g I day-' in animals acclimated to cold and warm conditions. In M. musculus, there was no significant effect of long-term exposure to cold on the rate of thyroid iodine secretion, it being 0.18�0.02 �g I day-' and 0.15�0.01 �g I day-' in the cold and warm conditions respectively. The large increase in thyroid activity in A. stuartii following acclimation to cold could explain the increase in metabolic rate. No periods of torpor in A. stuartii were detected in this study.
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Beckman, Juliey, and Alan Lill. "Space use by female agile antechinus: are teat number and home-range size linked?" Wildlife Research 43, no. 4 (2016): 348. http://dx.doi.org/10.1071/wr16001.
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Context The number of teats that a female agile antechinus (Antechinus agilis) possesses effectively determines her initial litter size. In the Otway Ranges, south-eastern Australia, numerous separate populations in which all females have either six or 10 teats occur fairly close together in similar, contiguous forest at comparable altitudes and latitudes. Six-teat and 10-teat females have a similar mean mass, but the latter have a 1.7 × greater reproductive potential and so should have a greater nutritional requirement while raising young than do six-teat females. Theoretically, they could meet this requirement by occupying larger and/or more exclusive home ranges during breeding than do six-teat females do (provided that their food-resource abundance is comparable), albeit at a greater energetic cost. Aims The aim of the study was to determine whether 10-teat A. agilis females occupied larger and less overlapping home ranges than did six-teat females. To interpret the findings more meaningfully, it was necessary to compare food abundance and habitat characteristics in areas occupied by the two phenotypes. Methods The investigation was conducted in six-teat and 10-teat A. agilis areas in cool temperate forest over 22 months. Population density was determined by mark–recapture methods and arthropod prey biomass and abundance by pitfall trapping. Vegetation structure and plant-taxa abundance and diversity were determined by standard plant-survey methods. Female home-range estimates determined by radio-tracking were based on 95% minimal convex polygons (MCP) and kernel analysis. Home-range overlap was based on 80% MCP range determinations and core areas were calculated from utilisation plots. Key results Female population density was 2.5 × lower in exclusively 10-teat than in exclusively six-teat populations. Radio-tracked 10-teat females’ home ranges less commonly overlapped those of identified female neighbours and, on average, were 1.5 × larger than ranges of six-teat females. Food abundance and composition was similar in six-teat and 10-teat areas, but ground cover was denser and more complex in the latter areas. Conclusions Food-resource availability was similar in the six-teat and 10-teat phenotype areas, so the larger, and probably more exclusive, home ranges of 10-teat females could reflect greater nutritional requirements resulting from having larger litters, and account for their lower population density. Implications The A. agilis teat-number variation pattern in the Otways may be a rare, visible example of ongoing incipient speciation. This makes it of great scientific and conservation value and it is important to document how the phenomenon operates.
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Pavey, Chris R., Nicola Goodship, and Fritz Geiser. "Home range and spatial organisation of rock-dwelling carnivorous marsupial, Pseudantechinus macdonnellensis." Wildlife Research 30, no. 2 (2003): 135. http://dx.doi.org/10.1071/wr03005.
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We studied home-range size, range length and spatial organisation of fat-tailed false antechinus, Pseudantechinus macdonnellensis, at Ormiston Creek, central Australia. Animals were tracked using transmitters implanted into the body cavity. Mean home-range size was 0.76 ha based on the minimum convex polygon (MCP) method and 1.14 ha based on the fixed kernel method (95% contour). Mean size of core areas of the home range was 0.07 ha based on the 50% kernel contour. Mean maximum range length was 148.83 m. Males occupied larger home-range areas than females (MCP: 0.98 v. 0.31 ha, 95% fixed kernel: 1.50 v. 0.43 ha) and also had greater maximum range lengths (180 v. 86 m). Home-range areas showed little overlap within the sexes; however, ranges of males overlapped those of females by an average of 37.95%. By comparison with data from a previous mark–recapture study at the same site, radio-tracking produced home-range estimates (MCP) that were greater by a factor of 24.5 for males and 15.5 for females, whereas maximum range lengths were lower for females, but similar for males. The results of this study support the proposition that the rock-dwelling P. macdonnellensis has a more stable home range and undergoes fewer long-range movements than similar-sized arid-zone dasyurids that occupy open environments. These differences likely result from the stability in resources provided by rocky habitats, specifically year-round availability of insects, availability of plentiful shelter sites that are very effective thermal buffers in both summer and winter, and a diversity of accessible microclimates.
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Bladon, R. V., C. R. Dickman, and I. D. Hume. "Effects of habitat fragmentation on the demography, movements and social organisation of the eastern pygmy-possum (Cercartetus nanus) in northern New South Wales." Wildlife Research 29, no. 1 (2002): 105. http://dx.doi.org/10.1071/wr01024.
Full textAbstract:
A population of eastern pygmy-possums (Cercartetus nanus) was studied in northern New South Wales for almost 3 years. A total of 98 pygmy-possums was captured, of which 52 were captured only once. The sex ratio of the population did not differ significantly from parity. Mid-way through the study, 1.4 ha of the 4.0-ha study site was cleared. Pre-clearing capture rates in nest boxes averaged 33.5 ± 5.8 captures per 100 box checks per month, and the population was estimated by three methods to be at least 15–20 animals. There was no significant difference in body mass between adult males (23.7 ± 6.3 g) and adult females (27.1 ± 7.7 g). Males had significantly larger short-term home ranges (0.35 ± 0.14 ha) than females (0.14 ± 0.06 ha) and tended to move over greater distances each night. Breeding occurred from summer to early winter, and juveniles and sub-adults entered the population in autumn and winter. The mean number of pouch young was 3.9. The most likely minimum size at which juveniles left their mother was 9–11 g. Adult body mass and condition were highly variable over time, and did not appear to be related to either the breeding season or Banksia flowering. Fourteen pygmy-possums were found torpid during the study. Population troughs occurred in late winter and spring and were associated with low survival and/or seasonal migration, possibly linked to the cessation of Banksia flowering in July and the lack of alternative food sources at this time and/or increased use of nest boxes by Antechinus stuartii during late winter. Post-clearing, capture rates fell to 7.8 ± 1.6 captures per 100 box checks per month, the estimated population size fell to 5–8 animals, and there was an almost total lack of juvenile/sub-adult recruitment into the population. The results support concerns that the long-term survival of the eastern pygmy-possum in New South Wales is threatened by continued land clearing throughout much of its present range.