Migration of feral pigs (Sus scrofa) in rainforests of north Queensland: fact or fiction?

2009 ◽  
Vol 36 (2) ◽  
pp. 110 ◽  
Author(s):  
J. Mitchell ◽  
W. Dorney ◽  
R. Mayer ◽  
J. McIlroy

The Wet Tropics bioregion of north Queensland has been identified as an area of global significance. The world-heritage-listed rainforests have been invaded by feral pigs (Sus scrofa) that are perceived to cause substantial environmental damage. A community perception exists of an annual altitudinal migration of the feral-pig population. The present study describes the movements of 29 feral pigs in relation to altitudinal migration (highland, transitional and lowland areas). Feral pigs were sedentary and stayed within their home range throughout a 4-year study period. No altitudinal migration was detected; pigs moved no more than a mean distance of 1.0 km from the centre of their calculated home ranges. There was no significant difference between the mean (±95% confidence interval) aggregate home ranges for males (8.7 ± 4.3 km2, n = 15) and females (7.2 ± 1.8 km2, n = 14). No difference in home range was detected among the three altitudinal areas: 7.2 ± 2.4 km2 for highland, 6.2 ± 3.9 km2 for transitional and 9.9 ± 5.3 km2 for lowland areas. The aggregate mean home range for all pigs in the present study was 8.0 ± 2.4 km2. The study also assessed the influence seasons had on the home range of eight feral pigs on the rainforest boundary; home ranges did not significantly vary in size between the tropical wet and dry seasons, although the mean home range in the dry season (7.7 ± 6.9 km2) was more than twice the home range in the wet season (2.9 ± 0.8 km2). Heavier pigs tended to have larger home ranges. The results of the present study suggest that feral pigs are sedentary throughout the year so broad-scale control techniques need to be applied over sufficient areas to encompass individual home ranges. Control strategies need a coordinated approach if a long-term reduction in the pig population is to be achieved.

2004 ◽  
Vol 31 (3) ◽  
pp. 327 ◽  
Author(s):  
Helen Puckey ◽  
Milton Lewis ◽  
David Hooper ◽  
Carrie Michell

Radio-telemetry was used to examine the home range, movement and habitat utilisation of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch in the Gulf of Carpentaria hinterland over a 13-month period. Two home-range estimators were used in the study, (i) minimum convex polygon (MCP) and (ii) fixed Kernel (KL), the latter also being used to estimate core areas of activity. Based on a total sample size of 21 individuals, the mean MCP home range was 11 165 m2, similar to the mean KL home range of 10 687 m2. Core areas were, on average, 11.9% of the KL home-range estimate. There was no significant difference in the size of home range or core area of males and females. Juveniles had a significantly smaller home range than adults. Home ranges and, to a lesser degree, core areas were non-exclusive, with multiple areas of overlap (averaging 41% and 38% respectively) within and between all age and gender categories, but especially between males and between juveniles. Movement frequencies showed that animals made many short forays in a central area close to the arithmetic home-range mean and far fewer long forays of distances greater than 100 m from the central area. The spatial and temporal activity of Z. palatalis was concentrated in, but not confined to, the 'valley' and 'slope' habitats, with fewer movements of rats onto the surrounding 'plateau'. Resource selection analyses showed that Z. palatalis tended to prefer valley and slope habitats over the plateau and that the proportion of point locations was significantly higher for adults in the slope habitat and for juveniles in the valley habitat. Most home ranges were centred on the ecotone between these two habitat types. Although isolated and spatially limited, these habitat patches provide high-quality resources for dense populations of Z. palatalis. This study exemplifies a species' attempt to make efficient use of a limited resource in an otherwise hostile environment. Even small declines in habitat area or quality due to their vulnerability to fire would impact upon many animals.


2000 ◽  
Vol 27 (1) ◽  
pp. 49 ◽  
Author(s):  
Stephen M. Jackson

The home-range of the mahogany glider was estimated, and its social behaviour examined, by following radio-collared animals over a two-year period within an area of continuous habitat and an adjacent area of fragmented habitat. The average home range within the continuous habitat was 19.25 ha for males and 20.34 ha for females, with male and female pairs occupying a combined area of 23.15 ha. In contrast, the average home range in the fragmented habitat was 11.05 ha for males and 6.80 ha for females, with a combined home-range of male and female pairs being 11.60 ha. The average overlap of the home ranges of paired males and females was 85.9%, compared with approximately 11% for non-paired individuals, which suggests that mahogany gliders are socially monogamous. For a total of 46 nights on which gliders were considered to behave normally for the entire night, the average foraging distance was 1506 m (range 590–3420 m) with no significant difference between males and females in either the continuous or fragmented habitat. There was, however, a significant difference in the distance individuals travelled during different times of the year, with longer distances being travelled during late dry season/wet season and shorter distances during the early to mid dry season. Mahogany gliders also travelled further when there was a high availability of nectar and pollen than when there was lower availability. A total of 83 dens (tree hollows) were recorded for the mahogany glider, with the poplar gum, Eucalyptus platyphylla, forest red gum, Eucalyptus tereticornis, and Clarkson's bloodwood, Corymbia clarksoniana, being most used.


1996 ◽  
Vol 23 (4) ◽  
pp. 435 ◽  
Author(s):  
N Dexter

The hypothesis that disturbance from a shooting exercise using a helicopter will influence the behaviour of surviving feral pigs, Sus scrofa, was tested on a population of radio-collared feral pigs in north-western New South Wales. No significant differences existed in hourly distance moved by pigs, diel variation in distance moved by pigs, or home-range size of pigs, between a radio-tracking session conducted immediately before a shooting exercise from a helicopter and a radio-tracking session conducted during and after the exercise. The position of the home ranges of feral pigs did not appear to be affected by the shooting exercise, although several radio-collared feral pigs moved into and out of the study area between tracking sessions. Overall, the results suggest that the disturbance caused by shooting has little effect on the behaviour of surviving feral pigs.


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.


Abstract.—Adult burbot <em>Lota lota </em>from Koocanusa Reservoir, Montana, USA were surgically implanted with acoustic (<em>n </em>= 28) and combined radio/acoustic tags (<em>n </em>= 12) to quantify movements and home range. Fish were tagged from November 2003 to April 2004, and tracking efforts were conducted approximately weekly during daylight hours on Koocanusa Reservoir using a motor boat during the period of mid-December 2003 to July 2005, which spanned two burbot spawning seasons. Six (15%) tagged burbot were never relocated after release, and an additional seven (17.5%) of the tagged burbot either died or shed their tag within 60 d after release. We relocated 34 marked burbot (85%) on at least three occasions (mean = 10.0). Burbot frequently used the deepest portions of the reservoir, especially during the summer months. We estimated that the mean 50%, 75%, and 90% kernel home ranges were 14.6, 22.6 and 32.3 km<sup>2</sup>, respectively. We found no evidence that burbot home range differed within the 2 years of this study. Although we did observe burbot moving a maximum distance of up to 64.3 km, we were unable to discern any general movement patterns by month or capture location. Individual burbot tagged in this study had relatively high fidelity to the original capture side of the reservoir, and almost half of our marked burbot were never relocated on the opposite side of the remnant Kootenai River thalweg, and those that did cross the thalweg do so infrequently. One burbot was entrained through Libby Dam approximately 134–276 d after capture and tagging.


Koedoe ◽  
1975 ◽  
Vol 18 (1) ◽  
Author(s):  
G.L. Smuts

Annual home range sizes were determined for 49 marked zebra family groups in the Kruger National Park. Sizes varied from 49 to 566 sq. km, the mean for the Park being 164 square kilometre. Mean home range sizes for different zebra sub-populations and biotic areas were found to differ considerably. Present herbivore densities have not influenced intra- and inter-specific tolerance levels to the extent that home range sizes have increased. Local habitat conditions, and particularly seasonal vegetational changes, were found to have the most profound influence on the shape and mean size of home ranges. The large home range sizes obtained in the Kruger Park, when compared to an area such as the Ngorongoro Crater, can be ascribed to a lower carrying capacity with respect to zebra, large portions of the habitat being sub-optimal, either seasonally or annually.


1994 ◽  
Vol 21 (1) ◽  
pp. 65 ◽  
Author(s):  
A Horsup

The home range and movements of the allied rock wallaby, Petrogale assimilis, a small macropod of the seasonally wet-dry tropics of Queensland, were studied over a 22-month period. There was no significant difference in the size of home ranges (95% isopleth) or core areas (65% isopleth) of males and females. Home ranges were generally elliptical with a mean size of 11.9 ha. Season had a major effect on home ranges. The following measures were all significantly greater in the dry seasons than in the wet seasons: home-range size (larger), home-range shape (more elongate), distance moved by females when feeding (longer), distance between shelter site and home-range centre of activity (longer). Feeding movements of males did not vary seasonally and were as long as dry-season movements of females, suggesting that movements of males are primarily determined by behavioural rather than physiological considerations. The overlap of rock-wallaby home ranges varied little between the sexes or seasons and averaged 38%. Core areas overlapped by an average of 22%; however, feeding adult rock-wallabies rarely met other conspecifics, except their partners. A comparison of the fixes of unpaired wallabies that had overlapping home ranges showed that temporal separation was occurring. In contrast, the home ranges of consort pairs showed extremely high temporal and spatial overlap. Rock-wallabies exhibited strong fidelity to their home ranges. The overlap of the seasonal home ranges and core areas of each individual rock wallaby averaged 68% and 52%, respectively. However, the seasonal home range of a socially immature adult male altered in location and size as he matured socially until it stabilised when he obtained a permanent consort.


2012 ◽  
Vol 33 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Margaretha Hofmeyr ◽  
Ulric van Bloemestein ◽  
Brian Henen ◽  
Craig Weatherby

Psammobates geometricus has a limited distribution in the southwestern Cape, South Africa, where it occurs in small habitat fragments separated by agricultural and urban developments. Space use and its determining factors thus represent critical information for the effective conservation of this species. We used radiotelemetry and thread-trailing to study the movement patterns and space use of geometric tortoises over an annual cycle, and estimated home ranges with minimum convex polygons and fixed-kernel methods. Home range size of geometric tortoises showed large inter-individual variation, and for females, a positive relationship to body size. Females, the larger sex, had larger home ranges and mean daily displacements than males had. Female space use was high through most of the year, except in the wet season, when food was abundant, temperatures relatively low, and soft soils allowed easy nesting. Males used more space and displaced further in the non-nesting than nesting season, perhaps to optimise mating opportunities in the non-nesting season before females ovulate. Home ranges were more elongate and overlapped more in fallow fields than in natural vegetation, suggesting that habitat degradation alters home range structure. The space geometric tortoises used for their annual activities ranged from 1.02 to 44.85 ha. The large home ranges and effects of habitat degradation should influence the size of reserves, and the destiny of geometric tortoises in small habitat fragments.


1996 ◽  
Vol 23 (6) ◽  
pp. 711 ◽  
Author(s):  
G Saunders ◽  
B Kay

The movements of a subalpine population of feral pigs were examined at Kosciusko National Park in southeastern New South Wales. Sufficient data were collected to estimate the home-range area of 20 pigs on the basis of 782 telemetry and trap locations. Mean (+/- s.d.) home-range size (minimum convex polygon method) for males (35.0 t 22.2 km*2) was significantly greater than that for females (1 1.1 +/- 5.2 km*2). Use of capture-recapture distances to estimate home-range size was considered inappropriate. A test for nomadism suggests that, although home ranges of pigs in this environment were larger than those reported for other pigs in Australia, the pigs were essentially sedentary. Management implications for this population are discussed.


1999 ◽  
Vol 26 (6) ◽  
pp. 847 ◽  
Author(s):  
Paul D. Meek

In this study 10 free-roaming domestic dogs from an Aboriginal community were radio-collared to determine the sizes of their home ranges and to observe their wandering behaviour. Half of the radio-tagged dogs went on wandering forays, while the other five roamed only within the vicinity of the community. Home-range size was highly variable within the study group: the mean for the wandering dogs was 927 ha whereas that of the sedentary dogs was 2.6 ha. Dogs travelled 8–30 km on forays. All forays were initiated at night and those that were recorded had an average duration of 26 h. Foray destinations were usually riparian habitats where macropod quarry were abundant.


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