scholarly journals Lessons from the Looming Extinction of the Tasmanian Devil

2008 ◽  
Vol 14 (3) ◽  
pp. 151 ◽  
Author(s):  
D. Lunney ◽  
M. Jones ◽  
H. McCullum
Keyword(s):  
Cancer Cells ◽  
Captive Breeding ◽  
Active Management ◽  
Tasmanian Devil ◽  
Population Bottlenecks ◽  
Low Genetic Diversity ◽  
Devil Facial Tumour Disease ◽  
In The Wild ◽  
Breeding Programmes ◽  
Infectious Cancer

Extinction in the wild is now regarded as likely for the Tasmanian Devil Sarcophilus harrissi. In 1996, a disease, Devil Facial Tumour Disease (DFTD), was seen in a Devil in the wild. By mid-2008, the population had declined by about 70%, and the disease was spreading rapidly from east to west across Tasmania. DFTD is an infectious cancer, passed from one Devil to another principally, or entirely, by biting. The bite implants the cancer cells; the low genetic diversity in the Tasmanian Devil population from previous population bottlenecks or selective sweeps means that those cancer cells are not recognized by the immune system and the cancer grows in the infected Devil. Estimates of the time to extinction in the wild range from about 20 to 35 years. If, however, there are resistant genotypes within the Devil population then extinction in the wild may be averted, with numbers augmented through captive breeding programmes and active management to spread these genotypes in the wild.

scholarly journals Low major histocompatibility complex diversity in the Tasmanian devil predates European settlement and may explain susceptibility to disease epidemics

2013 ◽  
Vol 9 (1) ◽  
pp. 20120900 ◽  
Author(s):  
Katrina Morris ◽  
Jeremy J. Austin ◽  
Katherine Belov
Keyword(s):  
Major Histocompatibility Complex ◽  
Tasmanian Devil ◽  
Major Histocompatibility ◽  
European Settlement ◽  
Low Genetic Diversity ◽  
Histocompatibility Complex ◽  
Devil Facial Tumour Disease ◽  
History Of ◽  
Mhc Diversity ◽  
Disease Epidemics

The Tasmanian devil ( Sarcophilus harrisii ) is at risk of extinction owing to the emergence of a contagious cancer known as devil facial tumour disease (DFTD). The emergence and spread of DFTD has been linked to low genetic diversity in the major histocompatibility complex (MHC). We examined MHC diversity in historical and ancient devils to determine whether loss of diversity is recent or predates European settlement in Australia. Our results reveal no additional diversity in historical Tasmanian samples. Mainland devils had common modern variants plus six new variants that are highly similar to existing alleles. We conclude that low MHC diversity has been a feature of devil populations since at least the Mid-Holocene and could explain their tumultuous history of population crashes.

An Agent-Based Model of the Spread of Devil Facial Tumor Disease in an Isolated Population of Tasmanian Devils

2012 ◽  
Vol 4 (4) ◽  
pp. 1-16
Author(s):  
Charles E. Knadler
Keyword(s):  
Life History ◽  
Cancer Cells ◽  
Tasmanian Devil ◽  
Isolated Population ◽  
Agent Based Model ◽  
Disease Mechanism ◽  
Agent Based ◽  
In The Wild ◽  
Devil Facial Tumor Disease

The Tasmanian devil population is being reduced in the wild at an alarming rate due to an epidemic, which is the result of an unusual disease mechanism. Infected animals “inject” cancer cells into other devils, which then clone the cells, developing tumors. These tumors are invariably fatal. Field observers have developed hypotheses that include a life- history change for the species. It is hypothesized that this change has the potential to improve the population’s survivability. An agent-based model of Tasmanian devils is used to evaluate these hypotheses. The model results suggest that the devils’ intra-gender aggression as well as their aggressive mating practices render the life-history change hypotheses’ correctness improbable.

Are any populations 'safe'? Unexpected reproductive decline in a population of Tasmanian devils free of devil facial tumour disease

2018 ◽  
Vol 45 (1) ◽  
pp. 31 ◽  
Author(s):  
K. A. Farquharson ◽  
R. M. Gooley ◽  
S. Fox ◽  
S. J. Huxtable ◽  
K. Belov ◽  
...  
Keyword(s):  
Conservation Management ◽  
Southern Oscillation ◽  
Demographic Data ◽  
Management Strategies ◽  
Natural Populations ◽  
Significant Decline ◽  
Tasmanian Devil ◽  
Devil Facial Tumour Disease ◽  
In The Wild ◽  
Reproductive Rates

Context Conservation management relies on baseline demographic data of natural populations. For Tasmanian devils (Sarcophilus harrisii), threatened in the wild by two fatal and transmissible cancers (devil facial tumour disease DFTD: DFT1 and DFT2), understanding the characteristics of healthy populations is crucial for developing adaptive management strategies to bolster populations in the wild. Aims Our analysis aims to evaluate contemporary reproductive rates for wild, DFTD-free Tasmanian devil populations, and to provide a baseline with which to compare the outcome of current translocation activities. Methods We analysed 8 years of field-trapping data, including demographics and reproductive rates, across 2004–16, from the largest known DFTD-free remnant population at Woolnorth, Tasmania. Key results Surprisingly, we found a dramatic and statistically significant decline in female breeding rate when comparing data collected from 2004–2009 with data from 2014–2016. Unfortunately we do not have any data from the intermediate years. This decline in breeding rate was accompanied by a subtle but statistically significant decline in litter sizes. These changes were not associated with a change in body condition over the same period. Furthermore, we could not attribute the decline in breeding to a change in population size or sex ratio. Preliminary analysis suggested a possible association between annual breeding rate and coarse measures of environmental variation (Southern Oscillation Index), but any mechanistic associations are yet to be determined. Conclusions The decline in breeding rates was unexpected, so further monitoring and investigation into potential environmental and/or biological reasons for the decline in breeding rate are recommended before the arrival of DFTD at Woolnorth. Implications Our results provide valuable data to support the conservation management of Tasmanian devils in their native range. They also highlight the importance of continued monitoring of ‘safe’ populations, in the face of significant threats elsewhere.

scholarly journals Hunting pressure is a key contributor to the impending extinction of Bornean wild cattle

2021 ◽  
Vol 45 ◽  
pp. 225-235
Author(s):  
PC Gardner ◽  
B Goossens ◽  
SBA Bakar ◽  
MW Bruford
Keyword(s):  
Population Growth ◽  
Captive Breeding ◽  
Population Decline ◽  
Active Management ◽  
Population Recovery ◽  
Central Unit ◽  
Population Parameters ◽  
Population Declines ◽  
Bos Javanicus ◽  
In The Wild

Widespread and unregulated hunting of ungulates in Southeast Asia is resulting in population declines and localised extinctions. Increased access to previously remote tropical forest following logging and changes in land-use facilitates hunting of elusive wild cattle in Borneo, which preferentially select secluded habitat. We collated the first population parameters for the Endangered Bornean banteng Bos javanicus lowi and developed population models to simulate the effect of different hunting offtake rates on survival and the recovery of the population using reintroduced captive-bred individuals. Our findings suggest that the banteng population in Sabah is geographically divided into 4 management units based on connectivity: the Northeast, Sipitang (West), Central and Southeast, which all require active management to prevent further population decline and local extinction. With only 1% offtake, population growth ceased in the Northeast and Sipitang. In the Southeast and Central units, growth ceased at 2 and 4% offtake, respectively. Extinction was estimated at 21-39 yr when offtake was 5%, occurring first in Sipitang and last in the Central unit. Supplementing the population with captive-bred individuals suggested that inbreeding was likely to limit population growth if using ≤20 founder individuals. Translocating 2 individuals for a 10 yr period, starting after 20 yr of captive breeding resulted in a faster population recovery over 100 yr and a lower extinction probability. Our results suggest that shielding the population against further losses from hunting will be key to their survival in the wild, provided that active management in the form of captive breeding is developed in the interim.

scholarly journals A Tasmanian devil breeding program to support wild recovery

2019 ◽  
Vol 31 (7) ◽  
pp. 1296 ◽  
Author(s):  
C. E. Grueber ◽  
E. Peel ◽  
B. Wright ◽  
C. J. Hogg ◽  
K. Belov
Keyword(s):  
Genetic Diversity ◽  
Reproductive Success ◽  
Genetic Research ◽  
Breeding Program ◽  
Natural Environments ◽  
Tasmanian Devil ◽  
Strategic Approach ◽  
Devil Facial Tumour Disease ◽  
Transmissible Cancer ◽  
In The Wild

Tasmanian devils are threatened in the wild by devil facial tumour disease: a transmissible cancer with a high fatality rate. In response, the Save the Tasmanian Devil Program (STDP) established an ‘insurance population’ to enable the preservation of genetic diversity and natural behaviours of devils. This breeding program includes a range of institutions and facilities, from zoo-based intensive enclosures to larger, more natural environments, and a strategic approach has been required to capture and maintain genetic diversity, natural behaviours and to ensure reproductive success. Laboratory-based research, particularly genetics, in tandem with adaptive management has helped the STDP reach its goals, and has directly contributed to the conservation of the species in the wild. Here we review this work and show that the Tasmanian devil breeding program is a powerful example of how genetic research can be used to understand and improve reproductive success in a threatened species.

scholarly journals Ethyl-Iophenoxic acid as a serum marker for oral baiting of carnivorous marsupials

2021 ◽  
Author(s):  
Ruth Pye ◽  
David S Nichols ◽  
Amy T. Gilbert ◽  
Andrew S Flies
Keyword(s):  
Field Trials ◽  
Serum Marker ◽  
Negative Control ◽  
Vaccine Uptake ◽  
Tasmanian Devil ◽  
Serum Samples ◽  
Baseline Serum ◽  
Wildlife Species ◽  
Devil Facial Tumour Disease ◽  
In The Wild

Context: Ethyl-Iophenoxic acid (Et-IPA) has been widely used as a bait biomarker to determine oral bait consumption by vertebrate wildlife species. Oral bait vaccines have been delivered to numerous wildlife species to protect them from disease. The Tasmanian devil (Sarcophilis harrisii), the largest extant carnivorous marsupial species, is threatened by the transmissible cancers known as devil facial tumour disease (DFTD). Development of a protective DFTD vaccine is underway, and an oral bait has been proposed to deliver the vaccine in the wild. The bait delivery system requires a biomarker that can be detected for several months post-consumption in Tasmanian devils. Aim: To determine the suitability of Et-IPA as a bait biomarker in the Tasmanian devil. Method: Two Tasmanian devils were fed 50 mg Et-IPA (4.5 to 7.1 mg Et-IPA/kg bodyweight). Liquid chromatography with tandem mass spectrometry (LC-MS/-MS) was used to directly measure Et-IPA in baseline serum samples and samples collected on days 1, 14, 26 and 56 post-baiting. Key results: Both devils retained serum Et-IPA concentrations at two orders of magnitude above negative control sera when this study concluded. Conclusions: Et-IPA is a useful bait biomarker for Tasmanian devils and can be included in future DFTD bait vaccine field trials to determine bait vaccine uptake.

scholarly journals Conservation by Captive Breeding: a General Survey

Oryx ◽  
1967 ◽  
Vol 9 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Richard Fitter
Keyword(s):  
Captive Breeding ◽  
European Bison ◽  
General Survey ◽  
Second Best ◽  
Wild Horse ◽  
In Captivity ◽  
In The Wild ◽  
Breeding Programmes ◽  
Père David’S Deer ◽  
Arabian Oryx

Breeding rare animals in captivity is only a second best but essential if they cannot be preserved in the wild, and in this zoos have an important part to play. Richard Fitter, hon. secretary of the Fauna Preservation Society, describes some of the most successful captive breeding programmes so far—Pére David's deer, European bison, Przewalski wild horse and Arabian oryx—and urges zoos to give serious attention now to the more difficult tasks of breeding primates and carnivores, of which several species, notably orang utans and the larger apes are endangered. He also suggests that zoos should anticipate the day when species now common become rare by establishing captive breeding programmes that would make them self-supporting in these animals.

scholarly journals Extensive population decline in the Tasmanian devil predates European settlement and devil facial tumour disease

2014 ◽  
Vol 10 (11) ◽  
pp. 20140619 ◽  
Author(s):  
Anna Brüniche-Olsen ◽  
Menna E. Jones ◽  
Jeremy J. Austin ◽  
Christopher P. Burridge ◽  
Barbara R. Holland
Keyword(s):  
Genetic Diversity ◽  
Environmental Changes ◽  
Southern Oscillation ◽  
Demographic History ◽  
Population Decline ◽  
Tasmanian Devil ◽  
Term Survival ◽  
Temporal Sampling ◽  
Low Genetic Diversity ◽  
Devil Facial Tumour Disease

The Tasmanian devil ( Sarcophilus harrisii ) was widespread in Australia during the Late Pleistocene but is now endemic to the island of Tasmania. Low genetic diversity combined with the spread of devil facial tumour disease have raised concerns for the species’ long-term survival. Here, we investigate the origin of low genetic diversity by inferring the species' demographic history using temporal sampling with summary statistics, full-likelihood and approximate Bayesian computation methods. Our results show extensive population declines across Tasmania correlating with environmental changes around the last glacial maximum and following unstable climate related to increased ‘El Niño–Southern Oscillation’ activity.

Major histocompatibility I gene diversity in the critically endangered Laysan duck (Anas laysanensis).

2014 ◽  
Vol 20 (1) ◽  
pp. 86 ◽  
Author(s):  
Philip Lavretsky ◽  
Andrew Engilis Jr ◽  
Jefferey L Peters
Keyword(s):  
Captive Breeding ◽  
Gene Diversity ◽  
Cost Effective ◽  
Major Histocompatibility ◽  
Mhc I ◽  
Island Endemic ◽  
Low Genetic Diversity ◽  
Cost Effective Method ◽  
Founder Populations ◽  
Breeding Programmes

Quantifying the genetic composition of founder populations is important to the success of reintroduction programmes, especially for bottlenecked and/or specialized species, such as island endemics. By implementing admixture schemes based on genetic variability, captive breeding programmes can minimize the detrimental effects of bottlenecking, inbreeding depression, outbreeding depression, etc. Particular attention has been given to genes within the major histocompatibility complex (MHC) due to their direct correlation to an individual’s immunity. However, isolating and amplifying MHC haplotypes remains difficult owing to the high diversity and paralogous nature. We describe a method of MHC I haplotype isolation based on an iterative process of primer design for the endangered island endemic, the Laysan duck (Anas laysanensis). Ultimately, haplotype-specific primers allow for direct genotyping after gel electrophoresis based on the presence/absence of their respective amplicons. Using the developed techniques, a total of eight unique haplotypes were isolated and assayed across 21 Laysan duck individuals from Laysan Island (N = 10) and Midway Atoll (N = 11). The presence/absence of seven haplotypes were variable across individuals with three haplotypes present in 95% of individuals, three in 38% of individuals, and one in 90% of individuals. The protocols described herein provide a simple, cost-effective method for isolating haplotypes and monitoring existing MHC variation in Laysan ducks, and the general approach can be applied to other molecular markers and species with low genetic diversity.

scholarly journals Effect of captivity on morphology: negligible changes in external morphology mask significant changes in internal morphology

2018 ◽  
Vol 5 (5) ◽  
pp. 172470 ◽  
Author(s):  
Stephanie K. Courtney Jones ◽  
Adam J. Munn ◽  
Phillip G. Byrne
Keyword(s):  
Sexual Dimorphism ◽  
Captive Breeding ◽  
Morphological Changes ◽  
External Morphology ◽  
Wild Animals ◽  
Internal Morphology ◽  
In Captivity ◽  
Two Generations ◽  
Breeding Programmes ◽  
Source Populations

Captive breeding programmes are increasingly relied upon for threatened species management. Changes in morphology can occur in captivity, often with unknown consequences for reintroductions. Few studies have examined the morphological changes that occur in captive animals compared with wild animals. Further, the effect of multiple generations being maintained in captivity, and the potential effects of captivity on sexual dimorphism remain poorly understood. We compared external and internal morphology of captive and wild animals using house mouse ( Mus musculus ) as a model species. In addition, we looked at morphology across two captive generations, and compared morphology between sexes. We found no statistically significant differences in external morphology, but after one generation in captivity there was evidence for a shift in the internal morphology of captive-reared mice; captive-reared mice (two generations bred) had lighter combined kidney and spleen masses compared with wild-caught mice. Sexual dimorphism was maintained in captivity. Our findings demonstrate that captive breeding can alter internal morphology. Given that these morphological changes may impact organismal functioning and viability following release, further investigation is warranted. If the morphological change is shown to be maladaptive, these changes would have significant implications for captive-source populations that are used for reintroduction, including reduced survivorship.

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