ORCID Profile
0000-0003-4432-3779
Current Organisations
Murdoch University
,
Department of Primary Industries and Regional Development
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Publisher: CSIRO Publishing
Date: 14-07-2021
DOI: 10.1071/WR20194
Abstract: Context Invasive species are a major cause of bio ersity loss across much of the world, and a key threat to Australia’s erse reptile fauna. There has been no previous comprehensive analysis of the potential impact of the introduced European red fox, Vulpes vulpes, on Australian reptiles. Aims We seek to provide an inventory of all Australian reptile species known to be consumed by the fox, and identify characteristics of squamate species associated with such predation. We also compare these tallies and characteristics with reptile species known to be consumed by the domestic cat, Felis catus, to examine whether predation by these two introduced species is compounded (i.e. affecting much the same set of species) or complementary (affecting different groups of species). Methods We collated records of Australian reptiles consumed by foxes in Australia, with most records deriving from fox dietary studies (tallying 000 s les). We modelled presence or absence of fox predation records against a set of biological and other traits, and population trends, for squamate species. Key results In total, 108 reptile species (~11% of Australia’s terrestrial reptile fauna) have been recorded as consumed by foxes, fewer than that reported for cats (263 species). Eighty-six species have been reported to be eaten by both predators. More Australian turtle species have been reported as consumed by foxes than by cats, including many that suffer high levels of predation on egg clutches. Twenty threatened reptile species have been reported as consumed by foxes, and 15 by cats. Squamate species consumed by foxes are more likely to be undergoing population decline than those not known to be consumed by foxes. The likelihood of predation by foxes increased with squamate species’ adult body mass, in contrast to the relationship for predation by cats, which peaked at ~217 g. Foxes, but not cats, were also less likely to consume venomous snakes. Conclusions The two introduced, and now widespread, predators have both compounding and complementary impacts on the Australian reptile fauna. Implications Enhanced and integrated management of the two introduced predators is likely to provide substantial conservation benefits to much of the Australian reptile fauna.
Publisher: Wiley
Date: 21-10-2018
DOI: 10.1111/AEC.12553
Publisher: Wiley
Date: 27-05-2021
DOI: 10.1111/MAM.12251
Abstract: The red fox Vulpes vulpes is one of the world’s most widespread carnivores. A key to its success has been its broad, opportunistic diet. The fox was introduced to Australia about 150 years ago, and within 30 years of its introduction was already recognised as a threat to livestock and native wildlife. We reviewed 85 fox diet studies (totalling 31693 s les) from throughout the species’ geographic range within Australia. Mammals were a major component of fox diet, being present in 70 ± 19% of s les across n = 160 locations. Invertebrates (38 ± 26% n = 130) and plant material (26 ± 25% n = 123) were also both staple foods and often the dominant food category recorded. Birds (13 ± 11% n = 137) and reptiles (10 ± 15% n = 132) were also commonly reported, while frogs were scarcely represented (1.6 ± 3.6% n = 111) in fox diet studies. Biogeographical differences reveal factors that likely determine prey availability. Diet composition varied with ecosystem, level of vegetation clearing and condition, and climate zone. S le type (i.e. stomach versus scat s les) also significantly influenced reporting of diet composition. Livestock and frogs were underrepresented in records based on analysis of scats, whereas small mammals (native rodents, dasyurid marsupials, and bats) were more likely to be recorded in studies of scats than in studies of stomach contents. Diet varied seasonally, reflecting activity patterns of prey species and food availability. This synthesis also captures temporal shifts in fox diet over 70 years (1951–2020), as foxes have switched to consuming more native species in the wake of successful broadscale biological control of the invasive European rabbit Oryctolagus cuniculus . Diet analyses, such as those summarised in this review, capture the evidence required to motivate for greater control of foxes in Australia. This synthesis also highlights the importance of integrated pest species management to meet bio ersity conservation outcomes.
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/WR16066
Abstract: Context Predation is one of the key contributors to mortality in freshwater turtles. Confirming the identity of predators is an important step towards conservation management action. Throughout Australia, the red fox (Vulpes vulpes) is suspected to apply significant and unsustainable predation pressure to turtle populations, killing adults and depredating nests however methods for confirming this are limited. Aims The present study used a range of methods to confirm predation of oblong turtle (Chelodina colliei) nests and adults by the introduced red fox. Methods First, depredated adult carapaces, and turtle egg-shell fragments from excavated nests were swabbed and analysed for trace DNA. Second, we used artificial turtle nests, monitored by camera traps, to analyse seasonal changes in the behaviour of foxes around sites where turtle nests are present, including over the nesting season. Last, we used scat analysis to identify the prevalence of turtle remains in fox diet. Key results Predominantly fox DNA was recovered from both adult carapaces and depredated eggs. In addition, camera traps recorded only foxes depredating artificial nests. Despite this evidence that foxes kill adults and excavated nests, we found that turtle remains were only a small part of the diet of foxes at this study site (hatchling or turtle egg shell were present in only 4% of 230 scats s led). The diet of these foxes was largely anthropogenic-sourced foods, such as fruit (e.g. figs, grapes, melons 81% of scats), sheep carrion (41%) and rodents (36%). Conclusions We conclude that DNA analysis, camera trapping and scat analysis are effective methods of identifying foxes as predators of adult turtle, and their nests. Furthermore, we found that anthropogenic foods (orchard crops, livestock or synanthropic species) may subsidise greater fox population size than might occur in their absence, thereby increasing potential pressure on these freshwater turtles. Implications Our findings give credence to the argument that foxes are effective predators of turtle adults and nests. In addition, the high proportion of anthropogenic food sources in the diet of foxes, and potential subsidisation, is an important consideration for land managers.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/RJ19051
Abstract: Exploration for oil and gas resources requiring the clearing of seismic lines has been occurring in central and northern Australia for many years. For ex le, seismic surveys have been conducted in the West Kimberley region of Western Australia since the 1960s. Despite this being a widespread practice, the recovery of vegetation on seismic lines has not been well studied. To better understand vegetation recovery in the West Kimberley, we conducted vegetation surveys on recovering seismic lines cleared using a raised-blade technique, from ∼two months to 4.9 years post-clearing, and compared them to paired control plots. Generally, the vegetation structure and community composition on seismic lines recovered quickly, with no discernible difference between control and seismic plots that were cleared more than 6 months prior. Some in idual vegetation characteristics (e.g. understorey density and overstorey cover) recovered slowly, whereas other characteristics such as the number of in idual grasses, recovered quickly. Vegetation recovery was confounded by the time since fire, which accounted for differences in vegetation structure at 1–2 years and 3–4 years since clearing. The fast recovery rate observed suggests that raised-blade clearing may not present a lasting impact on Pindan vegetation in the West Kimberley.
Publisher: Wiley
Date: 22-03-2019
DOI: 10.1111/JZO.12663
Publisher: Wiley
Date: 15-03-2022
DOI: 10.1111/DDI.13497
Abstract: Introduced predators negatively impact bio ersity globally, with insular fauna often most severely affected. Here, we assess spatial variation in the number of terrestrial vertebrates (excluding hibians) killed by two mammalian mesopredators introduced to Australia, the red fox ( Vulpes vulpes ) and feral cat ( Felis catus ). We aim to identify prey groups that suffer especially high rates of predation, and regions where losses to foxes and/or cats are most substantial. Australia. We draw information on the spatial variation in tallies of reptiles, birds and mammals killed by cats in Australia from published studies. We derive tallies for fox predation by (i) modelling continental‐scale spatial variation in fox density, (ii) modelling spatial variation in the frequency of occurrence of prey groups in fox diet, (iii) analysing the number of prey in iduals within dietary s les and (iv) discounting animals taken as carrion. We derive point estimates of the numbers of in iduals killed annually by foxes and by cats and map spatial variation in these tallies. Foxes kill more reptiles, birds and mammals (peaking at 1071 km −2 year −1 ) than cats (55 km −2 year −1 ) across most of the unmodified temperate and forested areas of mainland Australia, reflecting the generally higher density of foxes than cats in these environments. However, across most of the continent – mainly the arid central and tropical northern regions (and on most Australian islands) – cats kill more animals than foxes. We estimate that foxes and cats together kill 697 million reptiles annually in Australia, 510 million birds and 1435 million mammals. This continental‐scale analysis demonstrates that predation by two introduced species takes a substantial and ongoing toll on Australian reptiles, birds and mammals. Continuing population declines and potential extinctions of some of these species threatens to further compound Australia's poor contemporary conservation record.
Publisher: The Royal Society
Date: 10-2022
DOI: 10.1098/RSOS.220792
Abstract: Introduction of the domestic cat and red fox has devastated Australian native fauna. We synthesized Australian diet analyses to identify traits of prey species in cat, fox and dingo diets, which prey were more frequent or distinctive to the diet of each predator, and quantified dietary overlap. Nearly half (45%) of all Australian terrestrial mammal, bird and reptile species occurred in the diets of one or more predators. Cat and dingo diets overlapped least (0.64 ± 0.27, n = 24 location/time points) and cat diet changed little over 55 years of study. Cats were more likely to have eaten birds, reptiles and small mammals than foxes or dingoes. Dingo diet remained constant over 53 years and constituted the largest mammal, bird and reptile prey species, including more macropods otoroids, wombats, monotremes and bandicoots/bilbies than cats or foxes. Fox diet had greater overlap with both cats (0.79 ± 0.20, n = 37) and dingoes (0.73 ± 0.21, n = 42), fewer distinctive items (plant material, possums/gliders) and significant spatial and temporal heterogeneity over 69 years, suggesting the opportunity for prey switching (especially of mammal prey) to mitigate competition. Our study reinforced concerns about mesopredator impacts upon scarce/threatened species and the need to control foxes and cats for fauna conservation. However, extensive dietary overlap and opportunism, as well as low incidence of mesopredators in dingo diets, precluded resolution of the debate about possible dingo suppression of foxes and cats.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/WR19079
Publisher: Cambridge University Press (CUP)
Date: 02-12-2021
DOI: 10.1017/S0959270921000460
Abstract: Two introduced carnivores, the European red fox Vulpes vulpes and domestic cat Felis catus , have had extensive impacts on Australian bio ersity. In this study, we collate information on consumption of Australian birds by the fox, paralleling a recent study reporting on birds consumed by cats. We found records of consumption by foxes on 128 native bird species (18% of the non-vagrant bird fauna and 25% of those species within the fox’s range), a smaller tally than for cats (343 species, including 297 within the fox’s Australian range, a subset of that of the cat). Most (81%) bird species eaten by foxes are also eaten by cats, suggesting that predation impacts are compounded. As with consumption by cats, birds that nest or forage on the ground are most likely to be consumed by foxes. However, there is also some partitioning, with records of consumption by foxes but not cats for 25 bird species, indicating that impacts of the two predators may also be complementary. Bird species ≥3.4 kg were more likely to be eaten by foxes, and those .4 kg by cats. Our compilation provides an inventory and describes characteristics of Australian bird species known to be consumed by foxes, but we acknowledge that records of predation do not imply population-level impacts. Nonetheless, there is sufficient information from other studies to demonstrate that fox predation has significant impacts on the population viability of some Australian birds, especially larger birds, and those that nest or forage on the ground.
Publisher: Wiley
Date: 19-06-2014
DOI: 10.1111/JZO.12158
Publisher: CSIRO Publishing
Date: 31-01-2022
DOI: 10.1071/AM21016
Abstract: Generalist predators, such as the dingo (Canis familiaris), frequently use linear clearings as movement corridors, increasing their mobility, landscape access, and sometimes modifying predator–prey relationships. We quantified the diet of the dingo in the West Kimberley region of Western Australia and tested the hypothesis that clearing of seismic lines would result in a change to the diet of dingoes. A total of 199 scats were collected from inside and outside the footprint of a seismic survey at three collection time points (before and twice after the disturbance). Overall, the diet of dingoes varied over seasons (P = 0.003), and between control and treatment sites (P = 0.013) however, there was no evidence of a shift in diet caused by seismic clearing (time × treatment interaction term, P = 0.848). Cattle were the most frequently occurring item (frequency of occurrence = 65% of 199 s les the greatest value recorded in Australia), with greater consumption of cattle in control and treatment sites at the end of the dry season compared to the early dry season, likely driven by an increase in cattle mortality and susceptibility to predation. Despite dingoes using seismic lines as movement corridors, there is little evidence that this results in a change in their diet.
Location: Australia
No related grants have been discovered for Stuart Dawson.