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A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
A Photo Essay   trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings
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A Photo Essay trophic cascades following the disease-induced decline of the apex predator, the tasmanian devil - hollings

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As apex predators decline worldwide, there is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit. A transmissible cancer has led to the …

As apex predators decline worldwide, there is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit. A transmissible cancer has led to the apparent decline of populations of Tasmanian devils, the apex predator in the Tasmanian ecosystem. A new study in the February issue of Conservation Biology examines the substantial effects of the decline of the Tasmanian devil on terrestrial mammal fauna in Tasmania and sheds light on the critical role apex predators play in maintaining the integrity of ecosystems.

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  • 1. © Tracey Hollings Conservation Biology Volume 28, Number 1, February 2014 Featured Paper…
  • 2. Trophic Cascades Following the Disease-Induced Decline of an Apex Predator, the Tasmanian Devil Contributed Paper by: a photo essay… Conservation Biology February 2014 Mark Burgman, Editor-in-Chief www.conbio.org Published by Wiley Tracey Hollings Menna Jones Nick Mooney Hamish McCallum
  • 3. ©Rodrigo Hamede The Tasmanian Devil is threatened with extinction from a The Tasmanian Devil is threatened with extinction from a transmissible cancer, devil facial tumor disease. transmissible cancer, devil facial tumor disease.
  • 4. Trophic cascades following the disease-induced decline of an apex predator, the Tasmanian Devil Devil facial tumor disease (DFTD) has led to apparent population declines of Tasmanian Devils in excess of 95% in some areas and has spread to more than 80% of their range. (Hollings, 2013) Conservation Biology - Vol 28, Issue 1, February 2014
  • 5. ©Georgina Anderson The Tasmanian devil is the apex mammalian predator in the The Tasmanian devil is the apex mammalian predator in the Tasmanian ecosystem. As apex predators disappear worldwide, there Tasmanian ecosystem. As apex predators disappear worldwide, there is escalating evidence of their importance in maintaining the integrity is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit... and diversity of the ecosystems they inhabit... Wild Tasmanian devils at home in a den. Wild Tasmanian devils at home in a den.
  • 6. DFTD was first detected in the north-east of Tasmania in 1996. Prior to its arrival, devils were widespread and have been recorded in all Tasmanian vegetation types. ©Ryan Burrows
  • 7. Rapid Ecosystem Change and Polar Bear Conservation Conservation Letters Map of Tasmania showing individual spotlight survey transects within each of 4 regions representing different year ranges of arrival of DFTD (late, mid, disease-free, early). Years are range of arrival of DFTD in each region. A sub-adult female polar bear on a frozen lake along the shore of Hudson Bay. Small bears like this are usually wary of adult males which can be predatory. Hollings, 2013
  • 8. ©Hugh Maguire ©Ryan Burrows ©Ryan Burrows Unlike mainland Australia, Tasmania retains a nearly Unlike mainland Australia, Tasmania retains a nearly intact mammalian fauna community. intact mammalian fauna community.
  • 9. Trophic cascades following the disease-induced decline of an apex predator, the Tasmanian Devil Our results suggest that the decline of the Tasmanian devil, the apex mammalian predator in the Tasmanian ecosystem, has had a substantial effect on terrestrial mammal fauna, a result consistent with evidence from apex predator loss in other ecosystems (Hollings, 2013) Conservation Biology - Vol 28, Issue 1, February 2014
  • 10. Trophic cascades following the disease-induced decline of an apex predator, the Tasmanian Devil Maintaining populations of the devil in the Tasmanian ecosystem, at densities sufficient to exert top–down control, may protect populations of smaller mesopredators… Conservation Biology - Vol 28, Issue 1, February 2014
  • 11. © Tracey Hollings There is strong compelling evidence to support the There is strong compelling evidence to support the assertion that devils can exert top-down control on feral assertion that devils can exert top-down control on feral cat populations. cat populations.
  • 12. ©Tracey Hollings Feral cats like this one increase in areas where DFTD has been present the longest & feral cat occurrence is significantly and negatively associated with devils.
  • 13. As devil populations declined and cats increased, the smaller native mesopredator, the eastern quoll (pictured), declined, and there was no sign of population recovery, which lead to concerns for its conservation. ©Menna Jones
  • 14. The best-fitting generalized linear model (GLM) for the mean number of animals per transect for devils & eastern quolls. The best model, the linear model for feral cats, was not significantly different from models containing a DFTD arrival variable, so the secondbest model was used to illustrate devil facial tumor disease arrival effects (vertical lines, period of disease arrival; shaded areas, 95% CIs for GLMs; points, actual values).
  • 15. Trophic cascades following the disease-induced decline of an apex predator, the Tasmanian Devil Our results are consistent with assertions that DFTD causes rapid and severe population decline in devils that results in substantially reduced apex predator populations within a few years. There was no indication of population recovery, and with no effective management options at present that could aid recovery of wild populations, the trophic cascades in the Tasmanian ecosystem resulting from loss of devils are likely to continue. Conservation Biology - Vol 28, Issue 1, February 2014
  • 16. © Tracey Hollings SCB Members log in to your member home page at www.conbio.org to read: Trophic Cascades Following the Disease-induced Decline of an Apex Predator, the Tasmanian Devil Note: The February issue is freely available at: http://onlinelibrary.wiley.com/journal/10.1111/ (ISSN)1523-1739

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