The effectiveness of short‐term fox control in protecting a seasonally vulnerable species, the Eastern Long‐necked Turtle (<i>Chelodina longicollis</i>)

Robley, Alan; Howard, K.; Lindeman, Michael; Cameron, R. V.; Jardine, Andrew; Hiscock, David

doi:10.1111/emr.12199

Cited by 7 publications

(7 citation statements)

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“…Foxes destroyed such large numbers of turtle nests (>93% per year) that juvenile recruitment was reduced to nearly zero, and only adult turtles remained abundant within the population 9 . Management of invasive predators has thus been one of the primary mechanisms for preventing turtle declines in Australia 15,22,44,46 . However, its effectiveness has not been comprehensively assessed.…”

Section: Introductionmentioning

confidence: 99%

Conservation implications of turtle declines in Australia’s Murray River system

Dyke

Spencer

Thompson

et al. 2019

Sci Rep

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Conservation requires rapid action to be effective, which is often difficult because of funding limitations, political constraints, and limited data. Turtles are among the world’s most endangered vertebrate taxa, with almost half of 356 species threatened with extinction. In Australia’s Murray River, nest predation by invasive foxes (Vulpes vulpes) was predicted to drive turtle declines in the 1980s. We assessed populations of the broad-shelled turtle (Chelodina expansa), eastern long-necked turtle (C. longicollis), and Murray River turtle (Emydura macquarii) in the Murray River and some of its associated waterways. Our results suggest that the predicted decline is occurring. All three species are rare in the lower Murray River region, and were undetected in many locations in South Australia. Moreover, E. macquarii had considerable population aging almost everywhere, possibly due to comprehensive nest destruction by foxes. Chelodina longicollis also had population aging at some sites. Sustained low recruitment has potential to lead to collapses as turtles age, which is particularly worrying because it was predicted over 30 years ago and may have already occurred in South Australia. Our results show that turtle declines were not mitigated since that prediction. If the crash continues, a vertebrate guild responsible for considerable nutrient cycling in the aquatic ecosystem will disappear. Our results highlight a worst-case outcome when species declines are predicted, but insufficiently mitigated.

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Section: Introductionmentioning

confidence: 99%

Conservation implications of turtle declines in Australia’s Murray River system

Dyke

Spencer

Thompson

et al. 2019

Sci Rep

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“…However, the deployment of meat baits poisoned with sodium fluoroacetate (1080) is most popular because of its cost effectiveness (Saunders et al 2010). Controlling fox numbers with poison baits has been found to lower predation on nests of both freshwater and marine turtles in Australia (Spencer 2002;Madden Hof et al 2020), but a major fox-baiting programme at the Hattah Lakes in Victoria did not significantly reduce predation on artificial turtle nests (Robley et al 2016). Spencer et al (2017) suggested that poison baiting may be ineffective unless it results in the near elimination of the fox population because predation on artificial nests was independent of fox abundance unless the latter was extremely low.…”

Section: Discussionmentioning

confidence: 99%

“…Fox predation on eggs of Australian freshwater turtles was reported more than a century ago (Adelaide Advertiser, 3 January 1910, p. 8), and foxes also kill turtles emerging on land to nest or migrate between water bodies (Spencer 2002;Dawson et al 2016). Fox control, principally by poison baiting, is widely practised across Australia but its effectiveness in reducing destruction of freshwater turtle nests is questionable (Robley et al 2016). It is important that assertions that foxes are driving Australian freshwater turtle species to extinction are critically evaluated, because over-statement of the risk posed by foxes could result in resources for turtle conservation being devoted to efforts to reduce fox numbers when they would be more effectively directed elsewhere.…”

Section: Introductionmentioning

confidence: 99%

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Introduced red foxes (

Chessman

2021

Pacific Conserv. Biol.

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It has been asserted that introduced red foxes (Vulpes vulpes) destroy ~95% of nests of freshwater turtles in south-eastern Australia, are more efficient predators of freshwater turtle nests than Australian native predators, and are driving Australian freshwater turtle species to extinction. Available information was reviewed and analysed to test these assertions. Nest predation rates for all predators including foxes averaged 70% across Australia and 76% for south-eastern Australia compared to 72% for North America where freshwater turtles co-exist with many native predators, including foxes. Predation rates on Australian freshwater turtle nests did not differ significantly where foxes were included in the identified nest predators and where they were not, but sample sizes were very small. Evidence was lacking of foxes being the primary driver of population declines of Australian freshwater turtles, and some turtle populations are stable or increasing despite exposure to fox predation. Australian native species can be effective nest predators, and their role has probably been usurped by foxes to some degree. Where research shows that increased recruitment is necessary to conserve Australian freshwater turtle populations, strategies such as electric fencing of nesting beaches, nest protection cages and ex situ incubation of turtle eggs will probably be more cost-effective than efforts to reduce fox numbers. Further research is also needed to better understand the biological and environmental factors that regulate nest predation rates.

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“…Flags remained only briefly to take photos from each corner of the plot, to reference when checking the nests' survival weeks later. We spaced each nest at least 500 mm apart and dug each nest as a 150-200 mm deep hole, using an electric drill and soil auger (Robley et al, 2016). We buried three large unfertilized chicken eggs (sourced from a commercial farm) in each artificial nest to replicate the mass of an average clutch of turtle eggs (Spencer et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

Ineffectiveness of plastic mesh for protecting artificial freshwater turtle nests from red fox (Vulpes vulpes) predation

et al. 2023

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Invasive mammalian predators are efficient at driving native animal declines. The red fox (Vulpes vulpes) kills millions of endemic reptiles in Australia each year. In areas of south‐eastern Australia, the eastern long‐necked turtle (Chelodina longicollis) and Murray River turtle (Emydura macquarii) have declined by more than 50%. High rates of nest predation by foxes limit the recruitment of young turtles in these populations, but previous methods of fox control have been ineffective at protecting turtle nests. Here, we tested the effectiveness of plastic mesh for protecting artificial turtle nests from predation by foxes, in the mid‐Murray catchment, Victoria. We also tested whether protecting a large number of artificial nests in a given area encourages foxes to give up foraging following predictions from giving‐up density theory. We made a series of plots, each containing 32 artificial turtle nests. In each plot, we covered a percentage (0%, 25%, 50%, 81% or 100%) of the nests with either 1 or 2 sheets of plastic mesh. We used remote cameras to photograph and identify any predator that attacked nests in the plots. The cameras also allowed us to estimate the amount of time a fox was visible on each plot, as a metric of how much effort foxes expended on protected nests. Nest survival rate was not increased by either 1 or 2 sheets of mesh, and increasing the number of protected nests on a plot did not reveal a giving‐up density (GUD) value for fox foraging behaviour. Our study demonstrates that plastic mesh is not effective for protecting artificial turtle nests from foxes in this region.

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The effectiveness of short‐term fox control in protecting a seasonally vulnerable species, the Eastern Long‐necked Turtle (Chelodina longicollis)

Cited by 7 publications

References 47 publications

Conservation implications of turtle declines in Australia’s Murray River system

Conservation implications of turtle declines in Australia’s Murray River system

Introduced red foxes (

Ineffectiveness of plastic mesh for protecting artificial freshwater turtle nests from red fox (Vulpes vulpes) predation

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