Reverse ascertainment bias in microsatellite allelic diversity in owls (Aves, Strigiformes)
- Authors: Hogan, Fiona , Cooke, Raylene , Norman, Janette
- Date: 2009
- Type: Text , Journal article
- Relation: Conservation Genetics Vol. 10, no. 3 (2009), p. 635-638
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- Description: A rich source of markers may be overlooked by screening for polymorphism in the source species only. We screened 129 microsatellite loci isolated from the powerful owl (Ninox strenua) against two closely related species; Ninox connivens and Ninox novaeseelandiae. From the screening effort 20 polymorphic markers were isolated, including six loci which were originally discarded as they were monomorphic in the source species. Further cross-species amplification of all 20 loci across species from two families, Strigidae and Tytonidae, revealed unusually high levels of polymorphism within closely related species, and limited success within phylogenetically distant species. Routine screening of multiple species during the marker development phase can yield a wider range of polymorphic markers which can subsequently enhance cross-species amplification attempts
Predictive mapping of powerful owl (Ninox strenua) breeding sites using Geographical Information Systems (GIS) in urban Melbourne, Australia
- Authors: Isaac, Bronwyn , Cooke, Raylene , Simmons, Dianne , Hogan, Fiona
- Date: 2008
- Type: Text , Journal article
- Relation: Landscape and Urban Planning Vol. 84, no. (2008), p. 212-218
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- Description: Urban expansion is a principal process threatening biodiversity globally. It is predicted that over half of the world's population will reside in urban centres by 2010. If we are to conserve biodiversity, a shift in perspective from traditional ecological studies based in natural environments, to studies based in less natural environments is paramount. To effectively conserve species which occur in urban environments, comprehensive analysis is necessary to determine the processes that are driving this urban usage. Geographical Information Systems (GIS) technology provides a valuable tool for efficient spatial analysis and predictive mapping of species distributions. This study used GIS to analyze current breeding sites for the powerful owl, a vulnerable top order predator in urban Melbourne, Australia. GIS analysis suggests that a number of ecological attributes were influencing powerful owl usage of urban environments. Using these ecological attributes, predictive mapping was undertaken, which identified a number of potential breeding sites for powerful owls within urbanized Melbourne. Urban environments are traditionally perceived as “the wastelands” of natural environments, however, this study demonstrates that they have the potential to support apex predators, an important finding for the management of rare and threatened species.
Conservation biology : a 'crisis discipline'
- Authors: Hogan, Fiona , Cooke, Raylene
- Date: 2009
- Type: Text , Journal article
- Relation: The Victorian Naturalist Vol. 126, no. 3 (2009), p. 92-98
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- Description: Conserving biodiversity is of utmost importance on a global scale. Species conservation, however, is a challenging task, which is often compounded by a lack of knowledge of target species. New advances in information technology and molecular techniques, however, are enabling conservation biologists to obtain large amounts of data quickly, which will certainly aid in assigning conservation priorities. This article reviews the use of genetics in conservation biology and highlights, using the Powerful Owl Ninox strenua as an example, how DNA can be a valuable source of data
Molecular data contradicts historical records and cautions translocation of the Lord Howe Island masked owl
- Authors: Hogan, Fiona , Campbell, Catriona , Harrison, Katharine , Milledge, David , Cooke, Raylene
- Date: 2013
- Type: Text , Journal article
- Relation: Biological Conservation Vol. 159, no. (2013), p. 313-320
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- Description: Masked owls, reputedly all of the Tasmanian race (Tyto novaehollandiae castanops) were introduced onto Lord Howe Island (LHI) in the 1920s in an attempt to control the black rat (Rattus rattus). This attempt, however, has been unsuccessful and a co-eradication of the rats and masked owls has been planned to reduce the threat to endemic species and breeding seabirds on the island. As the Tasmanian masked owl is considered endangered, translocation of LHI masked owls to Tasmania has been suggested. Before translocation is considered the ancestry of the LHI masked owl needs to be confirmed, as LHI masked owls are typically smaller and paler than individuals occurring in Tasmania. Here we sequenced three sections of mitochondrial gene regions: cytochrome b, ATP6 and ND3 to assess the provenance of the LHI masked owl and screened a suite of microsatellite loci isolated from the barn owl (Tyto alba) to assess contemporary divergence. Phylogenetic analysis revealed two clades, one exhibited by individuals from LHI and south-eastern mainland Australia and the second by those from Tasmania. Cross species amplification of microsatellite loci was successful, with 18 loci polymorphic. Genotypic data revealed significant sub-structuring between LHI, south-eastern mainland Australia and Tasmania. Data presented here indicate that the south-eastern mainland masked owl was introduced to LHI and subsequently reproduced. The genetic integrity of the LHI masked owl population is therefore questionable and as such LHI individuals may not be suitable for translocation to Tasmania.
Optimizing the use of shed feathers for genetic analysis
- Authors: Hogan, Fiona , Cooke, Raylene , Burridge, Christopher , Norman, Janette
- Date: 2008
- Type: Text , Journal article
- Relation: Molecular Ecology Resources Vol. 8, no. 3 (2008), p. 561-567
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- Description: Shed feathers obtained by noninvasive genetic sampling (NGS) are a valuable source of DNA for genetic studies of birds. They can be collected across a large geographical range and facilitate research on species that would otherwise be extremely difficult to study. A limitation of this approach is uncertainty concerning the quality of the extracted DNA. Here we investigate the relationship between feather type, feather condition and DNA quality (amplification success) in order to provide a simple, cost-effective method for screening samples prior to genetic analysis. We obtained 637 shed feathers of the powerful owl (Ninox strenua) from across its range in southeastern Australia. The extracted DNA was amplified using polymerase chain reaction for a range of markers including mitochondrial DNA, ND3 and nuclear DNA, a simple sequence repeat (Nst02) and a portion of the CHD-1 gene (P2/P8). We found that feather condition significantly influenced the amplification success of all three loci, with feathers characterized as ‘good’ having greater success. Feather type was found to be of lower importance, with good quality feathers of all types consistently producing high success for all three loci. We also found that the successful amplification of multilocus genotypes was dependant on the condition of the starting material and was highly correlated with successful amplification of the sex-linked CHD-1 locus. Samples with low DNA quality have a higher probability of amplification failure and are more likely to produce incorrect genotypes; therefore, identifying samples with high DNA quality can save substantial time and cost associated with the genetic analysis of NGS. As a result, we propose a method for screening shed feathers in order to provide a subset of samples which will have a greater probability of containing high quality DNA suitable for the amplification of multilocus genotypes.
Insights into the breeding behaviour and dispersal of the Powerful Owl (Ninox Strenua) through the collection of shed feathers
- Authors: Hogan, Fiona , Cooke, Raylene
- Date: 2010
- Type: Text , Journal article
- Relation: Emu: Austral Ornithology Vol. 110, no. 2 (2010), p. 178-184
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- Description: The Powerful Owl is an elusive species inhabiting the forests of mainland eastern Australia. Obtaining crucial information on aspects of their breeding behaviour and dispersal has proven extremely difficult, even though other aspects of their ecology are well studied. Here we use molecular methods to investigate the breeding behaviour and dispersal of the Powerful Owl in two different habitats: highly fragmented forest along the urban fringe and continuous forest. DNA profiles of Powerful Owls were obtained predominately from shed feathers collected opportunistically between 1995 and 2006. Seven breeding pairs of Powerful Owls were identified, from which shed feathers were collected during 2003, 2004 and 2005. By comparing DNA profiles, one pair of Owls was found to have occupied the same breeding site for 10 years (1995–2005). The dispersal or movements of five offspring from this pair was also determined to be either of two scenarios: (1) the juvenile moves from the natal territory; however, isn’t breeding; and (2) the juvenile is recovered as part of a breeding pair. Two pairs of Owls breeding in the urban fringe habitat were closely related, but no incidences of extra-pair fertilisation were detected among pairs in either habitat. This study provides new information about the breeding behaviour and dispersal of the Powerful Owl, and shows the potential of using genetic data sourced from shed feathers for studying cryptic, rare or elusive species.
Reduced gene flow in a vulnerable species reflects two centuries of habitat loss and fragmentation
- Authors: Stevens, Kate , Harrisson, Katherine , Hogan, Fiona , Cooke, Raylene , Clarke, Rohan
- Date: 2018
- Type: Text , Journal article
- Relation: Ecosphere Vol. 9, no. 2 (2018), p. 1-15
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- Description: Understanding the effects of landscape modification on gene flow of fauna is central to informing conservation strategies that promote functional landscape connectivity and population persistence. We explored the effects of large-scale habitat loss and fragmentation on spatial and temporal patterns of gene flow in a threatened Australian woodland bird: the Grey-crowned Babbler Pomatostomus temporalis. Using microsatellite data, we (1) investigated historical (i.e., pre-fragmentation) and contemporary (i.e., post-fragmentation) levels of gene flow among subpopulations and/or regions, (2) identified first-generation migrants and likely dispersal events, (3) tested for signatures of genetic bottlenecks, (4) estimated contemporary and historical effective population sizes, and (5) explored the relative influences of drift and migration in shaping contemporary population structure. Results indicated that the functional connectivity of landscapes used by the Grey-crowned Babbler is severely compromised in the study area. The proportion of individuals that were recent immigrants among all subpopulations were low. Habitat fragmentation has led to a clear division between subpopulations in the east and west, and the patterns of gene flow exchange between these two regions have changed over time. The effective population size estimates for these two regions are now well below that required for long-term population viability (Ne < 100). Demographic history models indicate that genetic drift was a greater influence on subpopulations than gene flow, and most subpopulations show signatures of bottlenecks. Translocations to promote gene flow and boost genetic diversity in the short term and targeted habitat restoration to improve landscape functional connectivity in the long term represent promising conservation management strategies that will likely have benefits for many other woodland bird species. © 2018 Stevens et al.
Urbanization and raptors : trends and research approaches
- Authors: Cooke, Raylene , Hogan, Fiona , Isaac, Bronwyn , Weaving, Marian , White, John
- Date: 2018
- Type: Text , Book chapter
- Relation: Urban raptors: ecology and conservation of birds of prey in cities p. 64-75
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- Description: Urbanization presents a major global issue for the conservation and survival of many different species. With the increasing footprint of cities and intensification of our use of urban areas, wildlife faces extremely difficult challenges to live there. Understanding how species respond to urban processes and how to design urban landscapes that facilitate species’ presences are major emerging research and management priorities. Despite general negative responses to increasing urbanization, some animal taxa, both native and introduced, appear to benefit from urban environments by capitalizing on novel environments and abundant resources.1 Those that are common in urban systems display particular physical characteristics and ecological traits.2,3,4 They also frequently display a level of behavioral plasticity or tolerance, adjusting their behavior to interact with, and survive in, urban environments.5,6 Termed urban-adaptors,7 these species may exhibit altered spatial,8,9,10 foraging,11,12 and breeding behaviors,13 as detailed in chapter 2.
Powerful owls : possum assassins move into town
- Authors: Cooke, Raylene , Hogan, Fiona , Isaac, Bronwyn , Weaving, Marian , White, John
- Date: 2018
- Type: Text , Book chapter
- Relation: Urban Raptors: Ecology and Conservation of Birds of Prey in Cities Chapter 11 p. 152-165
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- Description: Once thought to live only in large forested areas, the powerful owl (Ninox strenua), Australia’s largest and most iconic of owls (figure 11.1), surprisingly is now turning up frequently in the cities of eastern Australia. Powerful owls require ample prey and large tree cavities for nest sites how this top-order predator is able to survive in human-dominated landscapes is an important question for conservation and the focus of ongoing research. The powerful owl is endemic to Australia, resident in the three eastern mainland states and the Australian Capital Territory, and classified nationally as “rare.”2,3 First described by Gould in 1838, powerful owls are an unusual raptor in that they do not exhibit reversed sexual size dimorphism, the prevalent trait among raptors in which females are larger than males. For reasons still not understood, male powerful owls grow to a height of 65 cm and weigh up to 1,700 g, compared to females, which grow to a height of 54 cm and weigh up to 1,308 g.1