Delineating genetic management units of sambar deer (Rusa unicolor) in south-eastern Australia, using opportunistic tissue sampling and targeted scat collection
- Authors: Davies, Christopher , Wright, Wendy , Wedrowicz, Faye , Pacioni, Carlo , Hogan, Fiona
- Date: 2022
- Type: Text , Journal article
- Relation: Wildlife Research Vol. 49, no. 2 (2022), p. 147-157
- Full Text:
- Reviewed:
- Description: Context: Invasive species are major drivers of biodiversity loss, requiring management to reduce their ecological impacts. Population genetics can be applied to delineate management units, providing information that can help plan and improve control strategies. Aim: The present study aims to use a genetic approach to test the existence of three previously proposed sambar deer populations in south-eastern Australia. In doing so, the study aims to delineate management units of sambar deer in south-eastern Australia. Methods: Sambar deer DNA was sourced opportunistically from tissue samples and targeted scat collection. Samples were collected from three areas in Victoria, south-eastern Australia: Mt Cole (MC), French Island (FI) and eastern Victoria (EV). Contemporary population structure was assessed using a suite of 11 polymorphic microsatellite markers. The number of maternal sambar deer lineages in south-eastern Australia was investigated through sequencing of the mitochondrial (mt)DNA control region. Key results: Three distinct genetic clusters were identified. Differentiation among inferred clusters was found to be high, with FST ranging from 0.24 between EV and FI clusters and 0.48 between MC and FI clusters. Two mtDNA haplotypes were identified; R.u1 was found throughout EV and FI, and R.u2 was unique to MC. DNA isolated from scats provided reliable data and proved critical for sampling areas where hunting and culling of deer are not generally undertaken. Conclusions: Three genetically distinct sambar deer management units in south-eastern Australia are defined-MC, FI and EV. Sambar deer control strategies should be applied to each management unit independently. This may be difficult or infeasible for the EV management unit, which is large and geographically complex. Further research may help identify additional fine-scale genetic structure in EV, allowing smaller, more practicable management units to be identified. Implications: Genetic data can be used to identify management units for invasive species, which will be critical for the development of future management strategies and improving control operations. The approach outlined here could also be applied to improve the management of other introduced deer species in south-eastern Australia. © 2022 CSIRO Open Access.
A DNA toolbox for non-invasive genetic studies of sambar deer (Rusa unicolor)
- Authors: Davies, Chris , Wright, Wendy , Wedrowicz, Faye , Hogan, Fiona
- Date: 2020
- Type: Text , Journal article
- Relation: Australian Mammalogy Vol. 42, no. 1 (2020), p. 58-66
- Full Text:
- Reviewed:
- Description: Invasive sambar deer (Rusa unicolor) are having significant detrimental impacts on natural environments in south-eastern Australia. Little, however, is known about their ecology, limiting evidence-based management strategies directed at reducing deer impacts. Genetic data, generated from DNA isolated from deer scats, can be used to fill ecological knowledge gaps. This study outlines a non-invasive genetic sampling strategy by which good-quality DNA from a single deer scat can be used to determine (1) species of origin, (2) sex and (3) a unique DNA profile. DNA from deer tissue and sambar deer scat samples were used to develop and optimise molecular methods to collect reliable genetic information. A DNA toolbox is presented that describes how to find, collect and store scat samples, isolate DNA and use molecular markers to generate informative genetic data. Generating genetic data using this approach will support studies aimed at acquiring ecological knowledge about sambar deer. Such knowledge will be critical for developing evidence-based recommendations to improve on-ground management decisions for sambar deer.
Detectability and activity patterns of sambar deer (Rusa unicolor) in Baw Baw National Park, Victoria
- Authors: Davies, Christopher , Wright, Wendy , Hogan, Fiona , Davies, Hugh
- Date: 2020
- Type: Text , Journal article
- Relation: Australian Mammalogy Vol. 42, no. 3 (2020), p. 312-320
- Full Text: false
- Reviewed:
- Description: Introduced sambar deer (Rusa unicolor) are increasing in abundance and distribution across much of south-eastern Australia and causing damage to native ecosystems. However, the current paucity of knowledge surrounding many aspects of sambar deer ecology is limiting our capacity to make informed management decisions, and properly gauge the extent of deer impacts. Here we investigate correlates of sambar deer detectability and describe activity patterns of sambar deer in Baw Baw National Park (BBNP) to inform control operations. Camera traps were deployed in BBNP between October and December 2016. We used an occupancy modelling framework to investigate sambar deer detectability and camera trap record time stamps to determine sambar deer activity patterns. Sambar deer were found to be significantly more detectable near roads and in areas of sparse tree density and displayed strong crepuscular activity patterns. Control operations carried out along roads at dawn and dusk could be effective, at least in the short term. Likewise, aerial culling could be an effective control option for sambar deer populations in BBNP. This study highlights the utility of camera trap data to inform the application of control operations for cryptic invasive species. © 2020 Australian Mammal Society.
Predicting deer-vehicle collision risk across Victoria, Australia
- Authors: Davies, Christopher , Wright, Wendy , Hogan, Fiona , Visintin, Casey
- Date: 2020
- Type: Text , Journal article
- Relation: Australian Mammalogy Vol. 42, no. 3 (2020), p. 293-301
- Full Text: false
- Reviewed:
- Description: The risk of deer-vehicle collisions (DVCs) is increasing in south-east Australia as populations of introduced deer expand rapidly. There are no investigations of the spatial and temporal patterns of DVC or predictions of where such collisions are most likely to occur. Here, we use an analytical framework to model deer distribution and vehicle movements in order to predict DVC risk across the State of Victoria. We modelled the occurrence of deer using existing occurrence records and geographic climatic variables. We estimated patterns of vehicular movements from records of average annual daily traffic and speeds. Given the low number of DVCs reported in Victoria, we used a generalised linear regression model fitted to DVCs in California, USA. The fitted model coefficients suggested high collision risk on road segments with high predicted deer occurrence, moderate traffic volume and high traffic speed. We used the California deer model to predict collision risk on Victorian roads and validated the predictions with two independent datasets of DVC records from Victoria. The California deer model performed well when comparing predictions of collision risk to the independent DVC datasets and generated plausible DVC risk predictions across the State of Victoria. © 2020 Australian Mammal Society.
- Description: This research was supported by an Australian Government Research Training Program (RTP) scholarship and Federation University Australia’s School of Health and Life Science.
Genetic structure and diversity of the koala population in South Gippsland, Victoria : A remnant population of high conservation significance
- Authors: Wedrowicz, Faye , Mosse, Jennifer , Wright, Wendy , Hogan, Fiona
- Date: 2018
- Type: Text , Journal article
- Relation: Conservation Genetics Vol. 19, no. 3 (2018), p. 713-728
- Full Text: false
- Reviewed:
- Description: In the Australian state of Victoria, the history of koalas and their management has resulted in the homogenisation and reduction of genetic diversity in many contemporary populations. Decreased genetic diversity may reduce a species’ ability to adapt to future environmental pressures such as climate change or disease. The South Gippsland koala population is considered to be unique in Victoria, as it is believed to be a remnant population, not originating from managed populations that have low genetic variation. This study investigated genetic structure and diversity of koalas in South Gippsland, with comparison to other populations in Victoria (French Island/Cape Otway, FI and Raymond Island, RI), New South Wales and south east Queensland. Population analyses were undertaken using both microsatellite genotype and mitochondrial DNA sequence data. Non-invasive sampling of koala scats was used to source koala DNA, allowing 222 South Gippsland koalas to be genotyped. Using nuclear data the South Gippsland koala population was found to be significantly differentiated (Djost 95% CI SG–RI = 0.03–0.06 and SG–FI = 0.08–012) and more diverse (AR 95% CI SG = 4.7–5.6, RI = 3.1–3.3, FI = 3.0–3.3; p = 0.001) than other Victorian koala populations, supporting the premise that koalas in the South Gippsland region are part of a remnant population, not derived from translocated island stock. These results were also supported by mitochondrial data where eight haplotypes (Pc4, Pc17, Pc26, Pc27, and Pc56–Pc59) were identified in South Gippsland while a single haplotype (Pc27) was found in all island koalas tested. Compared to other Victorian koala populations, greater genetic diversity found in South Gippsland koalas, may provide this population with a greater chance of survival in the face of future environmental pressures. The South Gippsland koala population is, therefore, of high conservation significance, warranting the implementation of strategies to conserve this population and its diversity into the future.
Isolating DNA sourced non-invasively from koala scats: a comparison of four commercial DNA stool kits
- Authors: Wedrowicz, Faye , Mosse, Jennifer , Wright, Wendy , Hogan, Fiona
- Date: 2018
- Type: Text , Journal article
- Relation: Conservation Genetics Resources Vol. , no. (2018), p.
- Full Text: false
- Reviewed:
- Description: Genetic sampling from faeces is a useful method for obtaining DNA samples non-invasively. The quantity and quality of DNA isolated from faecal samples is, however, an important factor affecting the success of downstream analyses. Commercial DNA isolation kits offer an efficient and convenient means for recovering DNA, but the kit methodology can influence the quantity and quality of DNA obtained. Comparisons of kit performance for the isolation of DNA from non-invasive sources for ecological studies based on genetic analysis are uncommon in the literature. This study compared the quantity and quality of DNA isolated from surface washings of fresh koala (Phascolarctos cinereus) faecal pellets (scats) using four commercial DNA isolation kits: Axygen® AxyPrep™ MAG Soil, Stool, and Water DNA Kit (AX), Bioline ISOLATE Fecal DNA Kit (BL), Qiagen QIAamp® Fast DNA Stool Mini Kit (QFS), and Qiagen QIAamp® DNA Stool Mini Kit (QS). DNA quantitation, standard PCR and electrophoresis, real time PCR and replicate genotyping using capillary electrophoresis were used to compare the performance of resultant DNA isolates. The performance of DNA isolated from koala scats varied substantially with the DNA kit utilised. All kits provided accurate genotypes but with differing amounts of missing data. Overall, kit AX performed best, providing DNA isolates of higher quantity and quality compared to kit QS, which has previously been thoroughly assessed for genotyping reliability using DNA from koala scats. Given the high variability noted, assessing kit performance is an important way to maximise data quality from non-invasively sourced DNA.
Using non-invasive sampling methods to determine the prevalence and distribution of Chlamydia pecorum and koala retrovirus in a remnant koala population with conservation importance
- Authors: Wedrowicz, Faye , Mosse, Jennifer , Wright, Wendy , Hogan, Fiona
- Date: 2018
- Type: Text , Journal article
- Relation: Wildlife Research Vol. 45, no. 4 (2018), p. 366-380
- Full Text:
- Reviewed:
- Description: Context Pathogenic infections are an important consideration for the conservation of native species, but obtaining such data from wild populations can be expensive and difficult. Two pathogens have been implicated in the decline of some koala (Phascolarctos cinereus) populations: Urogenital infection with Chlamydia pecorum and koala retrovirus subgroup A (KoRV-A). Pathogen data for a wild koala population of conservation importance in South Gippsland, Victoria are essentially absent. Aims This study uses non-invasive sampling of koala scats to provide prevalence and genotype data for C. pecorum and KoRV-A in the South Gippsland koala population, and compares pathogen prevalence between wild koalas and koalas in rescue shelters. Methods C. pecorum and KoRV-A provirus were detected by PCR of DNA isolated from scats collected in the field. Pathogen genetic variation was investigated using DNA sequencing of the C. pecorum ompA and KoRV-A env genes. Key results C. pecorum and KoRV-A were detected in 61% and 27% of wild South Gippsland individuals tested, respectively. KoRV-A infection tended to be higher in shelter koalas compared with wild koalas. In contrast with other Victorian koala populations sampled, greater pathogen diversity was present in South Gippsland. Conclusions In the South Gippsland koala population, C. pecorum is widespread and common whereas KoRV appears less prevalent than previously thought. Further work exploring the dynamics of these pathogens in South Gippsland koalas is warranted and may help inform future conservation strategies for this important population. Implications Non-invasive genetic sampling from scats is a powerful method for obtaining data regarding pathogen prevalence and diversity in wildlife. The use of non-invasive methods for the study of pathogens may help fill research gaps in a way that would be difficult or expensive to achieve using traditional methods.
Validating the use of non-invasively sourced DNA for population genetic studies using pedigree data
- Authors: Wedrowicz, Faye , Mosse, Jennifer , Wright, Wendy , Hogan, Fiona
- Date: 2017
- Type: Text , Journal article
- Relation: Web Ecology Vol. 17, no. 1 (2017), p. 9-18
- Full Text:
- Reviewed:
- Description: Non-invasive genetic sampling has provided valuable ecological data for many species - data which may have been unobtainable using invasive sampling methods. However, DNA obtained non-invasively may be prone to increased levels of amplification failure and genotyping error. Utilizing genotype data from 32 pedigreed koalas, this study aimed to validate the reliability of final consensus genotypes obtained using DNA isolated from koala scats. Pedigree analysis, duplicate genotyping, analysis of mismatched loci and tests for null alleles were used to look for evidence of errors. All genetically confirmed parent-offspring relationships were found to follow Mendelian rules of inheritance. Duplicate genotypes matched in all cases and there was no evidence of null alleles. Related individuals always had different 12-marker genotypes having a minimum of three unique loci (in one full sibling pair), a mode of seven unique loci and a maximum of 11 unique loci. This study demonstrates the capacity of DNA recovered from koala scats to provide reliable genotypes that can unequivocally discriminate individuals and infer parentage, provided data are missing from no more than two loci. Validating data obtained using non-invasive sampling is an important step, allowing potential problems to be identified at an early stage. © Author(s) 2017. CC Attribution 3.0 License.
- Description:
Non-invasive genetic sampling has provided valuable ecological data for many species - data which may have been unobtainable using invasive sampling methods. However, DNA obtained non-invasively may be prone to increased levels of amplification failure and genotyping error.
Utilizing genotype data from 32 pedigreed koalas, this study aimed to validate the reliability of final consensus genotypes obtained using DNA isolated from koala scats. Pedigree analysis, duplicate genotyping, analysis of mismatched loci and tests for null alleles were used to look for evidence of errors.
All genetically confirmed parent-offspring relationships were found to follow Mendelian rules of inheritance. Duplicate genotypes matched in all cases and there was no evidence of null alleles. Related individuals always had different 12-marker genotypes having a minimum of three unique loci (in one full sibling pair), a mode of seven unique loci and a maximum of 11 unique loci.
This study demonstrates the capacity of DNA recovered from koala scats to provide reliable genotypes that can unequivocally discriminate individuals and infer parentage, provided data are missing from no more than two loci. Validating data obtained using non-invasive sampling is an important step, allowing potential problems to be identified at an early stage. © Author(s) 2017. CC Attribution 3.0 License.
A non-invasive tool for assessing pathogen prevalence in koala (Phascolarctos cinereus) populations: detection of Chlamydia pecorum and koala retrovirus (KoRV) DNA in genetic material sourced from scats
- Authors: Wedrowicz, Faye , Saxton, Tom , Mosse, Jennifer , Wright, Wendy , Hogan, Fiona
- Date: 2016
- Type: Text , Journal article
- Relation: Conservation Genetics Resources Vol. 8, no. 4 (2016), p. 511-521
- Full Text: false
- Reviewed:
- Description: Pathogenic diseases may threaten the viability of wild animal populations, especially when already vulnerable. The mitigation of risks associated with pathogenic infections in populations is an important factor in conservation strategies. Koalas are of conservation concern across the north of their range and are affected by two main pathogens; Chlamydia pecorum and the koala retrovirus (KoRV). This study tested whether DNA from C. pecorum and KoRV could be detected in genetic material isolated from koala scats. Detection of C. pecorum in scat isolated DNA samples was compared with results obtained from urogenital swabs collected from the same individuals as part of an independent study. The ability to detect KoRV in scats from both northern and southern regions of the koala’s range was also assessed. There was a high level of concordance (5/6) between the detection of C. pecorum in DNA isolated from scats and urogenital swabs from the same individual. In positive samples, C. pecorumompA genotypes were identical between DNA from scats and urogenital swabs in two out of three cases. In samples from the south of the koala’s range, KoRV copy number was higher in DNA isolated from scats compared to DNA isolated from ear tissue, potentially indicating the detection of horizontally acquired infections. Our results demonstrate the ability to detect C. pecorum and KoRV in DNA isolated from koala scats. This method will be useful for studying the prevalence, transmission and impact of these pathogens in wild populations which may subsequently inform conservation management strategies. © 2016, Springer Science+Business Media Dordrecht.