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  • CSIRO Publishing  (3)
  • 1
    Online Resource
    Online Resource
    The dynamics of feral pig (Sus scrofa) populations in response to food supply
    CSIRO Publishing ; 2019
    In:  Wildlife Research Vol. 46, No. 3 ( 2019), p. 191-
    Details
    In: Wildlife Research, CSIRO Publishing, Vol. 46, No. 3 ( 2019), p. 191-
    Abstract: Context Feral pigs (Sus scrofa) are highly fecund, and populations can increase rapidly under favourable conditions. Population size can also fluctuate widely, driven largely by changes in juvenile mortality in response to food availability, but these relationships have only been explored on a limited number of sites and over short periods. Aims The present study aimed to investigate and quantify the numerical response of feral pig populations to changes in their food supply in north-eastern Australia. Methods Pig population densities were det ermined from aerial surveys conducted over a 21-year period on 10 regional blocks (~2000–6000 km2) throughout the Queensland rangelands. Densities were used to calculate annual exponential rates of increase (r), which were then corrected for anthropogenic mortality (baiting and commercial harvesting). Six proxy measures of annual food supply, including rainfall, pasture biomass and pasture growth (using the AussieGRASS model), were calculated for each survey block, and assessed as predictors of corrected r. The rates of increase predicted from the first half of the data series were then applied to initial population densities to estimate successive pig densities during the second period in each bioregion. Key results The most parsimonious model of the numerical response had parameters common to three bioregions, with rainfall in the 12 months between surveys being the best predictor variable. Modelled densities for each bioregion were a good fit to actual, observed densities. Relationships between r and each measure of food supply at the individual block level were inconsistent. Conclusions Using rainfall as a measure of food supply, the numerical response relationship provides a method for predicting the dynamics of feral pig populations at the bioregional scale. Predicting population dynamics at any one site using this relationship is less precise, suggesting that differences in landscape composition affect utilisation of resources supporting population growth. Implications The results from the present study could be used to predict feral pig population changes at the bioregional level, supplementing or reducing the need for more frequent, expensive population surveys. This improved ability to predict fluctuations in regional feral pig populations can help guide future management actions.
    Type of Medium: Online Resource
    ISSN: 1035-3712
    URL: Article
    DOI: 10.1071/WR17176
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2019
    SSG: 12
    SSG: 23
    Location Call Number Limitation Availability
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Bringing back the endangered bridled nail-tailed wallaby at Taunton National Park (Scientific) through effective predator control
    CSIRO Publishing ; 2022
    In:  Wildlife Research Vol. 49, No. 4 ( 2022-1-31), p. 382-398
    Details
    In: Wildlife Research, CSIRO Publishing, Vol. 49, No. 4 ( 2022-1-31), p. 382-398
    Abstract: Abstract Context Feral cats (Felis catus), wild dogs/dingoes (Canis familiaris) and foxes (Vulpes vulpes) are predators of the endangered bridled nail-tailed wallaby (BNTW; Onychogalea frenata). Predator-proof fencing is advocated as a solution to ensure their conservation in the wild. Aims The aims of this study were to determine whether predator control translated into a reduction in their activity, find evidence of cats preying on BNTWs and understand factors that influence changes in the BNTW population size living in an unfenced reserve, particularly focusing on the influence of cat and dog control and rainfall. Methods An activity index, calculated using spoor on sand pads and images on remote cameras, was undertaken to monitor predator activity. The stomach contents of cats caught were examined to determine how commonly BNTWs feature as a prey item. The size of the BNTW population and annual survival of individuals was assessed through annual capture–mark–recapture (CMR) surveys and vehicle spotlight counts. Rainfall was measured at the study site and using data from the Bureau of Meteorology. Key results The core BNTW population estimated by CMR data increased by 214% over 4 years (2013–2017), to 400 individuals in 2017, whereas spotlight data indicated that the population had increased by 262% over 8 years (2012–2020), to 1265 individuals in 2020. The percentage of small (≤3.5 kg) BNTWs caught increased substantially over the study period. There was no detectable difference in cat or dog activity following control and no correlation was found among predator activity, rainfall and BNTW survival. The remains of BNTWs were found in 20% of cats removed from the core BNTW area. Conclusions The study confirmed that cats frequently ate BNTWs, and a combination of control methods is required to manage the threat, but there was no statistical support for a relationship between predator activity and BNTW survival. Implications The study found that native species conservation in fox-free environments is possible without the need for predator-proof fences and the ongoing maintenance costs.
    Type of Medium: Online Resource
    ISSN: 1035-3712 , 1448-5494
    URL: Article
    DOI: 10.1071/WR21067
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2022
    SSG: 12
    SSG: 23
    Location Call Number Limitation Availability
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Evaluating the use of thermal imaging cameras to monitor the endangered greater bilby at Astrebla Downs National Park
    CSIRO Publishing ; 2020
    In:  Australian Mammalogy Vol. 42, No. 3 ( 2020), p. 329-
    Details
    In: Australian Mammalogy, CSIRO Publishing, Vol. 42, No. 3 ( 2020), p. 329-
    Abstract: Spotlight surveys are widely used to monitor arid-zone-dwelling species such as the greater bilby (Macrotis lagotis). These surveys require a sufficient sample size to adequately model detection probability. Adequate sample sizes can be difficult to obtain for low-density populations and for species that avoid light and or have poor eyeshine like the bilby. Abundance estimates based on burrow counts can be problematic because of the variable relationship between the number of burrows used and bilby abundance. In 2013, feral predators devastated a Queensland bilby population and a method was required that could locate and monitor the remaining bilbies. We report on a study that compared density estimates derived from spotlighting and thermal cameras. Bilbies were surveyed annually over three years, using spotlights and thermal cameras on different nights but using the same transects to compare the methods. On average, thermal cameras detected twice the number of bilbies per kilometre surveyed than spotlighting. Despite this difference in the number of bilbies detected, density estimates (bilbies km−2) were similar (thermal camera versus spotlight: 0.6 versus 0.2 (2014), 3.4 versus 3.4 (2015) and 4.8 versus 3.3 (2016)). Nevertheless, the larger sample size obtained using thermal cameras gave greater confidence in modelling detection probability.
    Type of Medium: Online Resource
    ISSN: 0310-0049
    URL: Article
    DOI: 10.1071/AM19040
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2020
    SSG: 12
    Location Call Number Limitation Availability
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    Online Resource
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