Spatial and dietary requirements of the chuditch (Dasyurus geoffroii) in a semiarid climatic zone

2012 ◽  
Vol 34 (1) ◽  
pp. 59 ◽  
Author(s):  
Kelly Rayner ◽  
Brian Chambers ◽  
Brent Johnson ◽  
Keith D. Morris ◽  
Harriet R. Mills

Knowledge of the ecology of the chuditch (Dasyurus geoffroii) is largely restricted to its distribution in mesic jarrah forests. There is a need for information regarding its ecology in semiarid zones where rainfall and consequently productivity are lower than mesic forests. Given that spatial requirements are strongly influenced by resource availability, it was expected that the chuditch in the semiarid zone would be present at lower densities and would have larger core home ranges (defined by daytime refuges) than those in the jarrah forests. The diet was also investigated by examining the contents of scats. Chuditch at Forrestania were trapped and six individuals were radio-tracked. The population density was one-third that of the lowest estimate reported from the jarrah forest and core home-range estimates were substantially larger, particularly for males. The diet included mammals, birds, reptiles, invertebrates, plants and rubbish, which was consistent with it being a generalist predator. Chuditch did have greater spatial requirements than in the jarrah forest, therefore different management regimes may be needed for populations occurring in the semiarid zone.


2016 ◽  
Vol 43 (4) ◽  
pp. 348 ◽  
Author(s):  
Juliey Beckman ◽  
Alan Lill

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.



1996 ◽  
Vol 23 (4) ◽  
pp. 401 ◽  
Author(s):  
SS Comport ◽  
SJ Ward ◽  
WJ Foley

The socio-ecology of Petauroides volans has been studied for subtropical and temperate populations, but not for the northern tropical subspecies, Petauroides volans minor. Data on the effects of a high population density on home ranges, time budgets and food-tree use were obtained by means of radio-telemetry. Three techniques were used to estimate home-range area (kernel, MCP and harmonic mean) and the kernel method was preferred. Estimates of home-range area (defined by the 95% kernel) gave mean values of 2.5 and 1.3 ha for males and females, respectively. Broad overlap of home ranges of males was observed, which has not been reported previously for populations of P. volans. Behaviour patterns for males and females were similar to those in previous studies, although the mating system may differ, possibly because of the high population density. Dietary patterns were similar to those previously reported for this species, the most important food items being young leaves and flower buds of particular eucalypt species, notably Eucalyptus acmenoides.



2012 ◽  
Vol 60 (3) ◽  
pp. 141 ◽  
Author(s):  
Jennyffer Cruz ◽  
Duncan R. Sutherland ◽  
Luke K.-P. Leung

The koomal (Trichosurus vulpecula hypoleucus) is a declining subspecies (‘near-threatened’), residing largely within the Western Australian jarrah forest, a forest managed for both conservation and for forestry (roughly half is available for logging). Information on the spatial dynamics of koomal is essential to evaluating whether logging prescriptions provide adequate protection for this threatened species. Here we describe the home range and territoriality of koomal, as well as the characteristics and use of their den trees, at multiple sites within the jarrah forest. We also compare the characteristics of den trees used by koomal against logging prescriptions and previous models that estimate availability of den trees. Results suggested that koomal home ranges varied between sites and sexes, with males having the larger home ranges. Koomal also maintained exclusive core territories, probably to protect their den trees from same-sex individuals. Den trees used by koomal had similar characteristics to those outlined in logging prescriptions, but also included two additional characteristics that may improve the retention of trees suitable for koomal: den trees were preferentially of marri (Corymbia calophylla) and wandoo (Eucalyptus wandoo) species, and had some level of canopy connectivity. Overall, findings from this study should help future evaluations of the effectiveness of logging prescriptions in providing adequate den availability for koomal.



2015 ◽  
Vol 42 (3) ◽  
pp. 223 ◽  
Author(s):  
Hugh W. McGregor ◽  
Sarah Legge ◽  
Joanne Potts ◽  
Menna E. Jones ◽  
Christopher N. Johnson

Context Feral cats (Felis catus) pose a significant threat to biodiversity in Australia, and are implicated in current declines of small mammals in the savannas of northern Australia. Basic information on population density and ranging behaviour is essential to understand and manage threats from feral cats. Aims In this study, we provide robust estimates of density and home range of feral cats in the central Kimberley region of north-western Australia, and we test whether population density is affected by livestock grazing, small mammal abundance and other environmental factors. Methods Densities were measured at six transects sampled between 2011 and 2013 using arrays of infrared cameras. Cats were individually identified, and densities estimated using spatially explicit capture–recapture analysis. Home range was measured from GPS tracking of 32 cats. Key results Densities were similar across all transects and deployments, with a mean of 0.18 cats km–2 (range = 0.09–0.34 km–2). We found no evidence that population density was related to livestock grazing or abundance of small mammals. Home ranges of males were, on average, 855 ha (±156 ha (95% CI), n = 25), and those of females were half the size at 397 ha (±275 ha (95% CI), n = 7). There was little overlap in ranges of cats of the same sex. Conclusions Compared with elsewhere in Australia outside of semiarid regions, feral cats occur at low density and have large home ranges in the central Kimberley. However, other evidence shows that despite this low density, cats are contributing to declines of small mammal populations across northern Australia. Implications It will be very difficult to reduce these already-sparse populations by direct control. Instead, land-management practices that reduce the impacts of cats on prey should be investigated.



1991 ◽  
Vol 18 (1) ◽  
pp. 49 ◽  
Author(s):  
G Saunders ◽  
B Kay

This study describes the movements of feral pigs at Sunny Corner in eastern New South Wales. Population density at this site was 2 pigs km-2. Twenty-two pigs (12 males and 10 females) were captured and fitted with telemetry transmitters. Aggregate home range for males (10.7 � 6.9 km2) was significantly greater than for females (4.9 � 1.4 km2) as was 24 h home range (1.4� 1.1 km2, males and 0.8 � 0.4 km2, females). Seasonal home ranges were greatest in the winter and smallest in the autumn. These differences were attributed to variations in food availability. During all seasons there was a preference for creeklines that had vegetative cover. This was the result of thermoregulatory needs, refuge availability and food supply. Peak activity throughout the study occurred between 1900 and 2400 hours with little movement during the middle of the day. The implications of these results to management programs are discussed.



2017 ◽  
Vol 44 (4) ◽  
pp. 316 ◽  
Author(s):  
K. S. Richardson ◽  
C. Rouco ◽  
C. Jewell ◽  
N. P. French ◽  
B. M. Buddle ◽  
...  

Context The Australian brushtail possums (Trichosurus vulpecula) introduction to New Zealand has exacted a heavy toll on native biodiversity and presented the country with its greatest wildlife reservoir host for bovine tuberculosis (TB). Management efforts to control both possums and TB have been ongoing for decades, and the biology of possums has been studied extensively in Australia and New Zealand over the past 50 years; however, we still do not have a clear understanding of its home-range dynamics. Aims To investigate determinants of home range size by using a uniquely large dataset in the Orongorongo Valley, a highly monitored research area in New Zealand and compare our findings with those of other studies. Methods Possum density was estimated, for subpopulations on four 13-ha cage-trap grids, by the spatially explicit capture–mark–recapture analysis of trapping data from 10 consecutive months. Home ranges were estimated from trap locations using a 100% minimum convex polygon (MCP) method for 348 individuals and analysed with respect to grid, age and sex. Key results Mean (standard error) possum density, estimated as 4.87 (0.19), 6.92 (0.29), 4.08 (0.21) and 4.20 (0.19) ha–1 for the four grids, was significantly negatively correlated with mean MCP home-range size. Grid, age, and the interaction of age and sex were significantly related to home-range size. Older possums had larger home ranges than did younger possums. When ‘juvenile cohort’ and ‘adult cohort’ data were analysed separately, to investigate the significant interaction, males in the ‘adult cohort’ had significantly larger home ranges than did females, with the grid effect still being apparent, whereas neither sex nor grid effects were significant for the ‘juvenile cohort’. Conclusions Our findings indicate that, in addition to density, age and sex are likely to be consistent determinants of possum home-range size, but their influences may be masked in some studies by the complexity of wild-population dynamics. Implications Our findings have strong implications regarding both disease transmission among possums and possum management. The fact that adult males occupy larger home ranges and the understanding that possum home range increases as population density decreases are an indication that males may be the primary drivers of disease transmission in possum populations. The understanding that possum home range increases as population density decreases could be a direct reflection of the ability of TB to persist in the wild that counteracts current management procedures. If individuals, and particularly males, infected with TB can withstand control measures, their ensuing home-range expansion will result in possible bacteria spread in both the expanded area of habitation and new individuals becoming subjected to infection (both immigrant possums and other control survivors). Therefore, managers should consider potential approaches for luring possum males in control operations.



2004 ◽  
Vol 31 (6) ◽  
pp. 559 ◽  
Author(s):  
M. L. Pope ◽  
D. B. Lindenmayer ◽  
R. B. Cunningham

This paper examines home-range attributes of 40 greater gliders (Petauroides volans) in five patches of remnant eucalypt forest surrounded by stands of radiata pine (Pinus radiata) near Tumut in south-eastern Australia. Fixed-kernel smoothing methods were used to estimate home-range size for P. volans. For males, home-range size varied from 1.38–4.10 ha (mean = 2.6 ± 0.8 ha, n = 12) and was significantly larger (P < 0.05) than for females (1.26–2.97 ha, mean = 2.0 ± 0.6 ha, n = 11). Home-range size increased significantly with increasing patch size and reduced patch population density. Thus, small patches had more animals per unit area with smaller home ranges and greater home-range overlap. Our findings illustrate flexibility in the use of space by P. volans. Such results have not previously been reported for P. volans or any other species of arboreal marsupial. Considerable home-range overlap (at 95th percentile isopleth level) was observed between male and female P. volans. Pairs of females also exhibited home-range overlap. Males tended to maintain home ranges exclusive of other males, although some shared common areas. Contrary to the large variations observed in home-range area, core areas (50th isopleth) remained relatively constant, regardless of patch size, population density or sex. This may indicate that core areas are an essential requirement for individuals and resources they contain cannot be shared with congeners.



1994 ◽  
Vol 72 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Christine R. Maher

Pronghorn (Antilocapra americana) vary in spatial organization. A literature review revealed that males occupied undefended home ranges in 12 populations and maintained territories in 11 populations. Low-productivity habitats and high or low population density could preclude territoriality. Using activity budgets, interaction rates, and home-range overlap, male social organization was described for a translocated pronghorn population in central California and compared with that of another population studied at Sheldon National Wildlife Refuge, Nevada, to determine if males were organized differently. Interaction rates were highest during spring, decreased in summer, then increased in late summer coincident with the rut. Home-range overlap ranged from 0 to 85% and averaged 30.6%; small amounts of overlap resulted from geographical features rather than from behavioral interactions. Males joined groups of females and fawns during summer; few behavior patterns associated with territoriality were observed. Males occupied undefended home ranges and this spacing system may have been influenced by food abundance and distribution, population density, or a combination of these factors. Comparisons between Sheldon and Carrizo males indicated that, while neither population was territorial, the behavior of Sheldon males was closer to the territoriality end of a continuum between territoriality and undefended home range than was that of Carrizo males. Behavior patterns were very similar between the populations but some occurred more frequently among Sheldon males. Both populations lived in semi-arid habitats, where low primary productivity would make the costs of maintaining territories greater than the benefits. Differences between the populations could be based on differences in population density. The Carrizo population was small and widely dispersed and male–male competition appeared low; therefore, the opportunity to interact with other males was lower than in areas of higher population density. Comparisons with other populations were difficult to make because of a lack of quantified data on behavioral and ecological variables. Such data are required if more is to be learned about the effects of ecology and demography on social organization.



1987 ◽  
Vol 8 (2) ◽  
pp. 153-163 ◽  
Author(s):  
Michael Stanner ◽  
Heinrich Mendelssohn

AbstractDuring a two-year study of the desert monitor (Varanus griseus) in a sand dune area south of the greater Tel Aviv area 21 adult monitors (8 males and 13 females) were captured and marked. Nine of the above monitors were equipped with radio transmitters, and were followed telemetrically for one year. The telemetered monitors maintained definite home ranges: 0.984 ± 0.165 km2, n = 4 for males and 0.319 ± 0.18 km2, n = 5 for females. The home range areas increased with the number of locations, reaching maxima after 30-70 locations. A considerable overlap of home ranges, between and within sexes, indicated that the species is not territorial. Varanus griseus forages over distances of 2 km or more. These forays often take the lizard through several habitats: unstabilized dunes, dense vegetation, construction areas, ruderal areas and a municipal garbage dump. A sex ratio of 1:1.6 (males:females) differs from that found in many previous Varanus studies.



2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bryan Andrew Lazarus ◽  
Azlan Che-Amat ◽  
Muhammad Muzammil Abdul Halim Shah ◽  
Azwan Hamdan ◽  
Hasliza Abu Hassim ◽  
...  

AbstractNatural salt lick (sira) is a strategic localisation for ecological wildlife assemblage to exhibit geophagy which may act as a population dynamic buffer of prey and predators. Undoubtedly, many agree that geophagy at natural licks is linked to nutritional ecology, health and assembly places facilitating social interaction of its users. Overall, natural salt licks not only save energy of obtaining nutrient leading to health maintenance but also forms the basis of population persistence. The Royal Belum Rainforest, Malaysia (Royal Belum) is a typical tropical rainforest in Malaysia rich in wildlife which are mainly concentrated around the natural salt lick. Since this is one of the most stable fauna ecology forest in Malaysia, it is timely to assess its impact on the Malayan tiger (Panthera tigris) home range dynamics. The three-potential home ranges of the Malayan tiger in this rainforest were selected based on animal trails or foot prints surrounding the salt lick viz (e.g. Sira Kuak and Sira Batu; Sira Rambai and Sira Buluh and Sira Papan) as well as previous sightings of a Malayan tiger in the area, whose movement is dependent on the density and distribution of prey. Camera traps were placed at potential animal trails surrounding the salt lick to capture any encountered wildlife species within the area of the camera placements. Results showed that all home ranges of Malayan tiger were of no significance for large bodied prey availability such as sambar deer (Rusa unicolor), and smaller prey such as muntjacs (Muntiacus muntjac) and wild boar (Sus scrofa). Interestingly, all home range harbour the Malayan tiger as the only sole predator. The non-significance of prey availability at each home range is attributed to the decline of the Malayan tiger in the rainforest since tigers are dependant on the movement of its preferred prey surrounding natural salt licks. Thus, the information from this study offers fundamental knowledge on the importance of prey-predator interaction at salt lick which will help in designing strategy in rewilding or rehabilitation programs of the Malayan tiger at the Royal Belum Rainforest.



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