Space use by female agile antechinus: are teat number and home-range size linked?

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.


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.



2021 ◽  
Author(s):  
Christen Herbert Fleming ◽  
Iman Deznabi ◽  
Shauhin Alavi ◽  
Margaret C. Crofoot ◽  
Ben T. Hirsch ◽  
...  

· Home-range estimates are a common product of animal tracking data, as each range informs on the area needed by a given individual. Population-level inference on home-range areas—where multiple individual home-ranges are considered to be sampled from a population—is also important to evaluate changes over time, space, or covariates, such as habitat quality or fragmentation, and for comparative analyses of species averages. Population-level home-range parameters have traditionally been estimated by first assuming that the input tracking data were sampled independently when calculating home ranges via conventional kernel density estimation (KDE) or minimal convex polygon (MCP) methods, and then assuming that those individual home ranges were measured exactly when calculating the population-level estimates. This conventional approach does not account for the temporal autocorrelation that is inherent in modern tracking data, nor for the uncertainties of each individual home-range estimate, which are often large and heterogeneous. · Here, we introduce a statistically and computationally efficient framework for the population-level analysis of home-range areas, based on autocorrelated kernel density estimation (AKDE), that can account for variable temporal autocorrelation and estimation uncertainty. · We apply our method to empirical examples on lowland tapir (Tapirus terrestris), kinkajou (Potos flavus), white‐nosed coati (Nasua narica), white-faced capuchin monkey (Cebus capucinus), and spider monkey (Ateles geoffroyi), and quantify differences between species, environments, and sexes. · Our approach allows researchers to more accurately compare different populations with different movement behaviors or sampling schedules, while retaining statistical precision and power when individual home-range uncertainties vary. Finally, we emphasize the estimation of effect sizes when comparing populations, rather than mere significance tests.



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.



1991 ◽  
Vol 18 (6) ◽  
pp. 677 ◽  
Author(s):  
M Phillips ◽  
PC Catling

Three adult red foxes (Vulpes vulpes) in a 20-km2 wilderness area of coastal south-eastern Australia were studied during pre-denning and denning. Home ranges were defined by geographic featues, but not by roads. The foxes occupied exclusive home ranges, and observations suggest that they were territorial and existed alone or, at most, in mated pairs. Home-range sizes were small (1.2-5.2 km2) compared with those in North America and Europe, but similar to those in England and Wales. During denning the female's activity became almost entirely diurnal. When not active, the vixen was with the cubs. Male activity during denning was nocturnal, but, as found for the female, inactive periods were spent near the suspected den-site in his home range. Habitats that were frequented most by all foxes were those with the highest abundance of either small or medium-sized mammals. Dry sclerophyll forest was used consistently by all foxes but heathland and the beaches were rarely frequented. Small and medium-sized mammals, which were abundant in all habitats except the beach and heathland, made up 52.6% of items in the scats.



2010 ◽  
Vol 32 (1) ◽  
pp. 23 ◽  
Author(s):  
Alan Robley ◽  
Andrew Gormley ◽  
David M. Forsyth ◽  
Alan N. Wilton ◽  
Danielle Stephens

To investigate movements and habitat selection by wild dogs we attached satellite-linked global positioning system (GPS) units to nine wild dogs (Canis lupus dingo and Canis lupus familiaris) captured in eastern Victoria in summer 2007. Units estimated locations at 30-min intervals for the first six months and then at 480-min intervals for six more months. DNA testing revealed all these wild dogs to be related. Home ranges of males were almost three times larger than those of females (males: 124.3 km2 ± 56.3, n = 4; females: 45.2 km2 ± 17.3, n = 5) and both sexes preferred subalpine grassland, shrub or woodland at the landscape and home-range scales. Wild dogs were recorded more often than expected within 25 m of roads and less often than expected within 25 m of watercourses. Wild dogs displayed higher-velocity movements with shallow turning angles (generally forwards) that connected spatial and temporal clusters comprising slower-velocity, shorter, and sharper turning movements. One wild dog travelled 230 km in 9 days before returning to its home range and another travelled 105 km in 87 days. The home-range sizes reported in this study are much larger than previously reported in south-eastern Australia. This finding, together with previous studies, suggests that the spatial scale at which wild dog management occurs needs to be reconsidered.



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.



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.



2018 ◽  
Vol 45 (2) ◽  
pp. 132 ◽  
Author(s):  
N. M. Robinson ◽  
C. I. MacGregor ◽  
B. A. Hradsky ◽  
N. Dexter ◽  
D. B. Lindenmayer

Context Reintroductions can be an effective means of re-establishing locally extinct or declining faunal populations. However, incomplete knowledge of variables influencing survival and establishment can limit successful outcomes. Aim We aimed to examine the factors (e.g. sex, body mass, release order) influencing the survival, dispersal, home range and habitat selection of reintroduced southern brown bandicoots (eastern subspecies; Isoodon obesulus obesulus) into an unfenced, predator-managed environment in south-eastern Australia (Booderee National Park). Methods Over 2 weeks in May 2016, six female and five male bandicoots were wild-caught in state forest and hard released into the park. Release locations were approximately evenly distributed between three primary vegetation types assessed as suitable habitat: heath, woodland and forest. Bandicoots were radio-tracked day and night for 4 weeks from the initial release date. Key results No mortality was detected. Males dispersed more than twice as far as females (male 704 m, female 332 m), but there was no significant sex bias in home range size. At the landscape scale, bandicoots preferentially selected home ranges that contained heath and avoided forest. Within home ranges, heath and woodland were both favoured over forest. Conclusions Post-release dispersal is sex-biased, but more data are required to determine the influence of other predictors such as body mass and release order. Within the release area, bandicoots favoured non-forest vegetation types. Implications Our study outlines factors influencing the establishment of reintroduced bandicoots. We recommend that future bandicoot reintroductions to Booderee National Park occur within areas of heath and woodland, and that subsequent releases consider the potentially larger spatial requirements and conspecific avoidance among male bandicoots. Our findings contribute new knowledge for improving translocation methods of a nationally endangered medium-sized mammal.



1991 ◽  
Vol 69 (6) ◽  
pp. 1516-1521 ◽  
Author(s):  
L. Scott Mills ◽  
Frederick F. Knowlton

Food abundance is an important factor determining space use in many species, but its effect on carnivore home range and territory size has rarely been investigated. We explored the relationship between food abundance for the coyote (Canis latrans) and space use in two study areas in the northern Great Basin, where the primary prey, the black-tailed jackrabbit (Lepus californicus), fluctuates dramatically in abundance. At one site, home ranges and territories were significantly larger during a time of prey-scarcity than when prey was abundant. Coyotes on the second site had similar-size home ranges and territories at low and high prey abundance, but a higher proportion and probably a higher number of individuals were transients during the prey-scarcity period. We propose mortality rates of coyotes as an important factor mediating adjustments in space use to food abundance, and suggest two mechanisms by which mortality might interact with food abundance. Higher mortality rates may simply permit more rapid adjustment of home range size to changing food conditions. Alternatively, higher mortality may selectively eliminate transients, thus reducing the impact of intruders in limiting the size of the remaining territories.



1993 ◽  
Vol 20 (3) ◽  
pp. 303 ◽  
Author(s):  
BW Weavers

Travelling paths and overnight roosts of the lace monitor, Varanus varius, were recorded by radiotracking during periods of up to 19 months in lowland open forest of south-eastern Australia. Home ranges were calculated by four methods: convex polygon (without correction for small sample size), convex polygon (with correction for small sample size), and two 95% probability ellipses. From field observations, I conclude that the convex polygon method without correction for sample size provides the most realistic description of the space used by V. varius. By this method, I calculated a mean (+/- s.d.) home range of 65 +/- 34 ha for 13 male V. varius (mean mass 5.1kg) that were radio-tracked for 2-19 months.



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