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1
Dique, David S., Harriet J. Preece, Jim Thompson e Deidré L. de Villiers. "Determining the distribution and abundance of a regional koala population in south-east Queensland for conservation management". Wildlife Research 31, n. 2 (2004): 109. http://dx.doi.org/10.1071/wr02031.
Testo completoAbstract (sommario):
Koala surveys were used to determine the distribution and abundance of a threatened regional koala population in south-east Queensland to assist with the development of effective conservation management programs. Daytime systematic searches of strip transects were conducted twice yearly from 1996 to 1999 to determine koala density at a number of sites in urban, remnant bushland and bushland strata. Mean density estimates for 27 survey sites ranged from 0.02 to 1.26 koalas ha–1. Koala densities were generally higher in large tracts and remnant patches of eucalypt bushland towards the centre of the region with lower but significant densities in urban areas. Two estimates of population size were obtained: 7230 (±1668, 95% confidence limit) and 6246 (±1444, 95% confidence limit). The estimate of 6246 was considered to provide a better indication of actual population size as it reduced the variation within strata and took into account the distribution of koalas across the region. It is likely that determining habitat areas for conservation based on where koalas actually occur rather than identifying distributions of 'preferred' tree species or community reports, as has been promoted in other studies, is a better indicator of the conservation significance of remnant habitat areas. Future koala-management programs should ensure that the significance of eucalypt bushland areas towards the centre of the study area is not compromised by future urban development and associated threats to koalas.
2
Sullivan, B. J., W. M. Norris e G. S. Baxter. "Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. II. Distribution and diet". Wildlife Research 30, n. 4 (2003): 331. http://dx.doi.org/10.1071/wr00032.
Testo completoAbstract (sommario):
This study used faecal pellets to investigate the broadscale distribution and diet of koalas in the mulgalands biogeographic region of south-west Queensland. Koala distribution was determined by conducting faecal pellet searches within a 30-cm radius of the base of eucalypts on 149 belt transects, located using a multi-scaled stratified sampling design. Cuticular analysis of pellets collected from 22 of these sites was conducted to identify the dietary composition of koalas within the region. Our data suggest that koala distribution is concentrated in the northern and more easterly regions of the study area, and appears to be strongly linked with annual rainfall. Over 50% of our koala records were obtained from non-riverine communities, indicating that koalas in the study area are not primarily restricted to riverine communities, as has frequently been suggested. Cuticular analysis indicates that more than 90% of koala diet within the region consists of five eucalypt species. Our data highlights the importance of residual Tertiary landforms to koala conservation in the region.
3
Ellis, W. A. H., B. J. Sullivan, A. T. Lisle e F. N. Carrick. "The spatial and temporal distribution of koala faecal pellets". Wildlife Research 25, n. 6 (1998): 663. http://dx.doi.org/10.1071/wr97028.
Testo completoAbstract (sommario):
Faecal pellets were collected under trees used by free-ranging koalas in south-western, central and south-eastern Queensland to determine the spatial and temporal distribution of pellets with respect to the activity of koalas. Deposition of faecal pellets by koalas was analysed according to the time of day at which the tree was occupied. For free-ranging koalas, 47% of daily faecal pellet output was recovered using a collection mat of 8 × 8 m placed under a day-roost tree. The best predictor of pellet production was the presence of a koala in a tree between 1800 hours and midnight. For other periods, there was no relationship between period of tree occupancy and faecal pellet recovery. There was a significant relationship between the average length of tree occupancy and the time of day that a koala entered a tree.
4
Wedrowicz, Faye, Jennifer Mosse, Wendy Wright e Fiona E. Hogan. "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". Wildlife Research 45, n. 4 (2018): 366. http://dx.doi.org/10.1071/wr17184.
Testo completoAbstract (sommario):
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.
5
Masters, Pip, Toni Duka, Steve Berris e Graeme Moss. "Koalas on Kangaroo Island: from introduction to pest status in less than a century". Wildlife Research 31, n. 3 (2004): 267. http://dx.doi.org/10.1071/wr03007.
Testo completoAbstract (sommario):
In less than a century the ecological profile of koalas on Kangaroo Island has shifted from that of a species introduced for conservation purposes to one of pest status. Between 1923 and 1925, 18 koalas were released on Kangaroo Island. Their numbers increased rapidly and in 1997 a population-control program was implemented based on a population estimate of 5000 koalas. During the course of this program, it became clear that the koala population on Kangaroo Island was much greater and more widely distributed than previously thought, hence a more comprehensive population survey was carried out.In 2000–01 the koala population size was calculated using a stratified sampling approach based on five 'catchment units' and three habitat classifications that were known to support koalas. The koala population was estimated to be ~27 000 koalas in 2001. There were substantial differences in koala density in the low-, medium- and high-quality habitat within each catchment unit, and therefore large differences in the spatial distribution of koalas across Kangaroo Island. This revised population estimate has substantial ramifications for the Kangaroo Island Koala Management Program that was set in place in 1997.
6
Clifton, I. D., W. A. H. Ellis, A. Melzer e G. Tucker. "Water turnover and the northern range of the koala (Phascolarctos cinereus)." Australian Mammalogy 29, n. 1 (2007): 85. http://dx.doi.org/10.1071/am07010.
Testo completoAbstract (sommario):
Water turnover for koalas is positively correlated with the moisture content of selected trees suggesting that browse choice was driven by water requirements in summer but energy demands in winter. We compared the distribution of the koala to relative humidity and found that the bioregional delineation of the koala?s range corresponds closely to regions experiencing an average 9am relative humidity of less than 80% in February. This indicates that the northern coastal distribution of the koala may be limited by respiratory evaporative water loss as a cooling mechanism.
7
Predavec, Martin, Daniel Lunney, Ian Shannon, Dave Scotts, John Turbill e Bill Faulkner. "Mapping the likelihood of koalas across New South Wales for use in Private Native Forestry: developing a simple, species distribution model that deals with opportunistic data". Australian Mammalogy 37, n. 2 (2015): 182. http://dx.doi.org/10.1071/am15001.
Testo completoAbstract (sommario):
In Private Native Forestry in New South Wales, species-specific provisions in the code of practice are triggered by the presence of koalas (Phascolarctos cinereus), based on existing database records in the Atlas of NSW Wildlife. Whereas Species Distribution Modelling allows questions to be posed regarding the distribution of a species, and how it relates to environmental variables and threats, the key question, in many management situations, is whether or not a species is, or has been, present at a particular location, rather than the overall predicted distribution of the species. This is particularly the case for such a high-profile species as the koala. In this project, we developed a simple distribution model for the koala in New South Wales based on the proportion of koala records from within a suite of mammal records in 10 km × 10 km cells. This provides a measure of the likelihood of koalas being present. At the same time it allows deficiencies in the data to be highlighted, and recommendations made for further survey. This model and map will allow the potential for more robust and transparent decisions to be made regarding koala protection in areas proposed for private native forestry.
8
Dique, David S., Deidré L. de Villiers e Harriet J. Preece. "Evaluation of line-transect sampling for estimating koala abundance in the Pine Rivers Shire, south-east Queensland". Wildlife Research 30, n. 2 (2003): 127. http://dx.doi.org/10.1071/wr02042.
Testo completoAbstract (sommario):
Distance sampling using line transects has not been previously used or tested for estimating koala abundance. In July 2001, a pilot survey was conducted to compare the use of line transects with strip transects for estimating koala abundance. Both methods provided a similar estimate of density. On the basis of the results of the pilot survey, the distribution and abundance of koalas in the Pine Rivers Shire, south-east Queensland, was determined using line-transect sampling. In total, 134 lines (length 64 km) were used to sample bushland areas. Eighty-two independent koalas were sighted. Analysis of the frequency distribution of sighting distances using the software program DISTANCE enabled a global detection function to be estimated for survey sites in bushland areas across the Shire. Abundance in urban parts of the Shire was estimated from densities obtained from total counts at eight urban sites that ranged from 26 to 51 ha in size. Koala abundance in the Pine Rivers Shire was estimated at 4584 (95% confidence interval, 4040–5247). Line-transect sampling is a useful method for estimating koala abundance provided experienced koala observers are used when conducting surveys.
9
Lunney, Daniel, Stephen Phillips, John Callaghan e Dionne Coburn. "Determining the distribution of Koala habitat across a shire as a basis for conservation: a case study from Port Stephens, New South Wales". Pacific Conservation Biology 4, n. 3 (1998): 186. http://dx.doi.org/10.1071/pc980186.
Testo completoAbstract (sommario):
The Australian National Koala Conservation Strategy recognizes the importance of conserving Koalas in their existing habitat, particularly through the integration of Koala conservation into local government planning (ANZECC 1998). The aim of this study was to define, rank and map the distribution of Koala habitat in Port Stephens Shire, New South Wales. The procedure was to merge the results of two independent survey techniques, each of which was interpreted using a vegetation map specifically prepared for this study. A field survey used a plot-based sampling protocol to determine tree species preferences based on the presence/absence of Koala faecal pellets. Data were obtained on 8 764 trees comprising 19 eucalypt and 12 non-eucalypt species. A high-profile community survey obtained 2 756 Koala records. Koala habitat maps from both survey methods were examined as overlapping GIS layers. Combined Koala habitat categories were then devised, ranked and mapped across the Shire. This study provides a practical and repeatable means of identifying and conserving Koala habitat in existing remnant vegetation over which local government has planning jurisdiction.
10
Ellis, Murray V., Susan G. Rhind, Martin Smith e Daniel Lunney. "Changes in the distribution of reports of the koala (Phascolarctos cinereus) after 16 years of local conservation initiatives at Gunnedah, north-west New South Wales, Australia". Pacific Conservation Biology 23, n. 1 (2017): 63. http://dx.doi.org/10.1071/pc16004.
Testo completoAbstract (sommario):
In the early 1990s the koala became the mascot for a revegetation program to control salinity on agricultural land around Gunnedah in New South Wales, and a snapshot of the koala’s distribution in the shire was collected at that time, mainly via a mail survey. After the success of tree plantings in the 1990s, the koala population of the Liverpool Plains became a focus of increasing local conservation efforts, as well as research to explain koala population dynamics. This included a repeat mail survey conducted in 2006, which enabled the comparison of the reported distributions to be undertaken. These two citizen science surveys had different response rates but both produced extensive datasets. By 2006, koalas were reported from a wider extent than in 1990, particularly to the north and east of the town, and in more developed agricultural areas, but with highest densities in areas with more than 25% wooded vegetation. In 1990, koalas were reported mostly from locations that were surrounded by more than 40% wooded vegetation with the core of the distribution being on the basalt hills south of the town of Gunnedah. Koalas were also reported with increased relative frequency in the town, and this formed the core of the reported sightings at that time. There were still no reports from many of the vegetated hilly margins of the shire. The observed changes in the pattern of reporting reflects the actual distribution of koalas intersected with the likelihood of observation and the willingness of people to report koalas, and also identify the areas that may be under-sampled to determine the true habitat breath of koalas in the area.
11
Seabrook, Leonie, Clive McAlpine, Greg Baxter, Jonathan Rhodes, Adrian Bradley e Daniel Lunney. "Drought-driven change in wildlife distribution and numbers: a case study of koalas in south west Queensland". Wildlife Research 38, n. 6 (2011): 509. http://dx.doi.org/10.1071/wr11064.
Testo completoAbstract (sommario):
Context Global climate change will lead to increased climate variability, including more frequent drought and heatwaves, in many areas of the world. This will affect the distribution and numbers of wildlife populations. In south-west Queensland, anecdotal reports indicated that a low density but significant koala population had been impacted by drought from 2001–2009, in accord with the predicted effects of climate change. Aims The study aimed to compare koala distribution and numbers in south-west Queensland in 2009 with pre-drought estimates from 1995–1997. Methods Community surveys and faecal pellet surveys were used to assess koala distribution. Population densities were estimated using the Faecal Standing Crop Method. From these densities, koala abundance in 10 habitat units was interpolated across the study region. Bootstrapping was used to estimate standard error. Climate data and land clearing were examined as possible explanations for changes in koala distribution and numbers between the two time periods. Key results Although there was only a minor change in distribution, there was an 80% decline in koala numbers across the study region, from a mean population of 59 000 in 1995 to 11 600 in 2009. Most summers between 2002 and 2007 were hotter and drier than average. Vegetation clearance was greatest in the eastern third of the study region, with the majority of clearing being in mixed eucalypt/acacia ecosystems and vegetation on elevated residuals. Conclusions Changes in the area of occupancy and numbers of koalas allowed us to conclude that drought significantly reduced koala populations and that they contracted to critical riparian habitats. Land clearing in the eastern part of the region may reduce the ability of koalas to move between habitats. Implications The increase in hotter and drier conditions expected with climate change will adversely affect koala populations in south-west Queensland and may be similar in other wildlife species in arid and semiarid regions. The effect of climate change on trailing edge populations may interact with habitat loss and fragmentation to increase extinction risks. Monitoring wildlife population dynamics at the margins of their geographic ranges will help to manage the impacts of climate change.
12
Quigley, Bonnie L., e Peter Timms. "The Koala Immune Response to Chlamydial Infection and Vaccine Development—Advancing Our Immunological Understanding". Animals 11, n. 2 (3 febbraio 2021): 380. http://dx.doi.org/10.3390/ani11020380.
Testo completoAbstract (sommario):
Chlamydia is a significant pathogen for many species, including the much-loved Australian marsupial, the koala (Phascolarctos cinereus). To combat this situation, focused research has gone into the development and refinement of a chlamydial vaccine for koalas. The foundation of this process has involved characterising the immune response of koalas to both natural chlamydial infection as well as vaccination. From parallels in human and mouse research, it is well-established that an effective anti-chlamydial response will involve a balance of cell-mediated Th1 responses involving interferon-gamma (IFN-γ), humoral Th2 responses involving systemic IgG and mucosal IgA, and inflammatory Th17 responses involving interleukin 17 (IL-17) and neutrophils. Characterisation of koalas with chlamydial disease has shown increased expression within all three of these major immunological pathways and monitoring of koalas’ post-vaccination has detected further enhancements to these key pathways. These findings offer optimism that a chlamydial vaccine for wider distribution to koalas is not far off. Recent advances in marsupial genetic knowledge and general nucleic acid assay technology have moved koala immunological research a step closer to other mammalian research systems. However, koala-specific reagents to directly assay cytokine levels and cell-surface markers are still needed to progress our understanding of koala immunology.
13
Callaghan, John, Clive McAlpine, David Mitchell, Jane Thompson, Michiala Bowen, Jonathan Rhodes, Carol de Jong, Renee Domalewski e Alison Scott. "Ranking and mapping koala habitat quality for conservation planning on the basis of indirect evidence of tree-species use: a case study of Noosa Shire, south-eastern Queensland". Wildlife Research 38, n. 2 (2011): 89. http://dx.doi.org/10.1071/wr07177.
Testo completoAbstract (sommario):
Context Mapping the habitat and distribution of a species is critical for developing effective conservation plans. Koala (Phascolarctos cinereus, Phascolarctidae) distribution is constrained by the nutritional and shelter requirements provided by a relatively small number of key tree species in any given area. Identifying these key species provides a practical foundation for mapping koala habitat and prioritising areas for conservation. Aims To determine key tree species for koalas in Noosa Shire (south-eastern Queensland, Australia) as a basis for mapping koala habitat quality. Methods We applied a faecal-pellet survey methodology in 1996/97 to assess evidence of use by koalas of 4031 trees from 96 randomly stratified survey sites across different eucalypt-forest and woodland communities. Results were compared with those from a later survey undertaken in 2001/02 involving 5535 trees from 195 sites that were distributed across broadly similar areas with the aim to investigate aspects of koala landscape ecology. Key results A total of 66.7% of the 1996/97 survey sites contained koala faecal pellets, recorded under 953 eucalypt trees (14 species) and 1670 non-eucalypt trees (27 species). The proportion of trees at a given survey site that had koala faecal pellets at the base ranged from 2.2% to 94.7% (mean = 31.13 ± 2.59% s.e.). For the 2001/02 dataset, koala pellets were found at 55.4% of sites, from 794 eucalypt and 2240 non-eucalypt trees. The proportion of trees with pellets ranged from 3% to 80% (mean = 21.07 ± 1.77% s.e.). Both the 1996/97 and 2001/02 surveys identified the same three tree species (forest red gum, Eucalyptus tereticornis, swamp mahogany, E. robusta, and tallowwood, E. microcorys) as the highest-ranked for koala use in the study area. Three additional species (red mahogany, E. resinifera, small-fruited grey gum, E. propinqua, and grey ironbark, E. siderophloia) were identified in the 1996/97 surveys as key eucalypt species. Of the non-eucalypts in the 1996/97 dataset, coast cypress pine (Callitris columellaris) and broad-leaved paperbark (Melaleuca quinquenervia) ranked highest for use by koalas, followed by pink bloodwood (Corymbia intermedia) and brush box (Lophostemon confertus). White bottlebrush (Callistemon salignus), hard corkwood (Endiandra sieberi), M. quinquenervia and C. intermedia ranked highest in the 2001/02 dataset. The findings showed significantly greater use of larger eucalypts (i.e. 300-mm to >600-mm diameter at breast height). Conclusions The identified key eucalypt species, being the critical limiting resource for koalas, were used to assign koala habitat-quality classes to mapped regional ecosystem types to create a Koala Habitat Atlas (KHA) for Noosa Shire. The combined two highest quality classes based on abundance of the key eucalypt species comprised only 15.7% of the total land area of the Shire. Implications The KHA approach provides a practical and repeatable method for developing koala habitat-suitability mapping for national-, regional- and local-scale conservation and recovery planning purposes.
14
Lunney, Daniel, Carol Esson, Chris Moon, Murray Ellis e Alison Matthews. "A Community-based Survey of the Koala, Phascolarctos cinereus, in the Eden Region of South-eastern New South Wales". Wildlife Research 24, n. 1 (1997): 111. http://dx.doi.org/10.1071/wr94034.
Testo completoAbstract (sommario):
A community-based postal survey (questionnaire and map) was undertaken in the Eden region of south-eastern New South Wales in 1991–92 to help determine the local distribution of koalas and to obtain information on which to base a regional plan of management for koalas. The 1198 replies from the II 600 households in the region represented all parts of the area surveyed. The survey responses suggest that koalas are rare in the Eden region, and that the number of koalas has been constantly low for the last four decades. The records are scattered both chronologically and geographically. National Parks and Nature Reserves have never been the stronghold of local koala populations, and freehold land, particularly farmland, is not a major reservoir of koalas. Most koalas reported were in, or adjacent to, State Forests, particularly Murrah–Berrnagui and Tantawangalo–Glenbog–Yurammie. These areas appear to contain the core of the surviving koala population of the region. An assessment of the vegetation where koalas were sighted indicated that dry forest is the preferred habitat. The once abundant and widespread local koala population of late last century has been reduced by habitat loss and fragmentation to a few small, isolated populations. This regional survey, which was undertaken by use of a carefully constructed questionnaire, revealed an invaluable source of records and contributed 70% of the records in the database used for this study. This study also laid a basis for assessing koala management options in south-eastern New South Wales.
15
Lunney, Daniel, Mathew S. Crowther, Ian Shannon e Jessica V. Bryant. "Combining a map-based public survey with an estimation of site occupancy to determine the recent and changing distribution of the koala in New South Wales". Wildlife Research 36, n. 3 (2009): 262. http://dx.doi.org/10.1071/wr08079.
Testo completoAbstract (sommario):
The present study demonstrates one solution to a problem faced by managers of species of conservation concern – how to develop broad-scale maps of populations, within known general distribution limits, for the purpose of targeted management action. We aimed to map the current populations of the koala, Phascolarctos cinereus, in New South Wales, Australia. This cryptic animal is widespread, although patchily distributed. It principally occurs on private property, and it can be hard to detect. We combined a map-based mail survey of rural and outer-urban New South Wales with recent developments in estimating site occupancy and species-detection parameters to determine the current (2006) distribution of the koala throughout New South Wales. We were able to define the distribution of koalas in New South Wales at a level commensurate with previous community and field surveys. Comparison with a 1986 survey provided an indication of changes in relative koala density across the state. The 2006 distribution map allows for local and state plans, including the 2008 New South Wales Koala Recovery Plan, to be more effectively implemented. The application of this combined technique can now be extended to a suite of other iconic species or species that are easily recognised by the public.
16
Adams-Hosking, Christine, Hedley S. Grantham, Jonathan R. Rhodes, Clive McAlpine e Patrick T. Moss. "Modelling climate-change-induced shifts in the distribution of the koala". Wildlife Research 38, n. 2 (2011): 122. http://dx.doi.org/10.1071/wr10156.
Testo completoAbstract (sommario):
Context The impacts of climate change on the climate envelopes, and hence, distributions of species, are of ongoing concern for biodiversity worldwide. Knowing where climate refuge habitats will occur in the future is essential to conservation planning. The koala (Phascolarctos cinereus) is recognised by the International Union for Conservation of Nature (IUCN) as a species highly vulnerable to climate change. However, the impact of climate change on its distribution is poorly understood. Aims We aimed to predict the likely shifts in the climate envelope of the koala throughout its natural distribution under various climate change scenarios and identify potential future climate refugia. Methods To predict possible future koala climate envelopes we developed bioclimatic models using Maxent, based on a substantial database of locality records and several climate change scenarios. Key results The predicted current koala climate envelope was concentrated in south-east Queensland, eastern New South Wales and eastern Victoria, which generally showed congruency with their current known distribution. Under realistic projected future climate change, with the climate becoming increasingly drier and warmer, the models showed a significant progressive eastward and southward contraction in the koala’s climate envelope limit in Queensland, New South Wales and Victoria. The models also indicated novel potentially suitable climate habitat in Tasmania and south-western Australia. Conclusions Under a future hotter and drier climate, current koala distributions, based on their climate envelope, will likely contract eastwards and southwards to many regions where koala populations are declining due to additional threats of high human population densities and ongoing pressures from habitat loss, dog attacks and vehicle collisions. In arid and semi-arid regions such as the Mulgalands of south-western Queensland, climate change is likely to compound the impacts of habitat loss, resulting in significant contractions in the distribution of this species. Implications Climate change pressures will likely change priorities for allocating conservation efforts for many species. Conservation planning needs to identify areas that will provide climatically suitable habitat for a species in a changing climate. In the case of the koala, inland habitats are likely to become climatically unsuitable, increasing the need to protect and restore the more mesic habitats, which are under threat from urbanisation. National and regional koala conservation policies need to anticipate these changes and synergistic threats. Therefore, a proactive approach to conservation planning is necessary to protect the koala and other species that depend on eucalypt forests.
17
Reckless, Hailee J., Michael Murray e Mathew S. Crowther. "A review of climatic change as a determinant of the viability of koala populations". Wildlife Research 44, n. 7 (2017): 458. http://dx.doi.org/10.1071/wr16163.
Testo completoAbstract (sommario):
The koala (Phascolarctos cinereus) occupies a broad range of eastern and southern Australia, extending over tropical coastal, semiarid inland and temperate regions. In many areas koala populations are under threat, in particular from the direct and indirect effects of ongoing habitat destruction due to increased urbanisation and other anthropogenic processes. Climate change presents additional threats to the integrity of koala habitats because many species of food and non-food trees have narrow climate envelopes and are unable to adapt to altered temperatures and rainfall. Climate extremes also produce physiological stresses in koalas that may increase the likelihood of outbreaks of chlamydiosis and other diseases. Climate change–related increases in the relative content of toxic chemicals in leaves are further stresses to the koala after ingestion. In addition, populations that originated from a small number of founder individuals are at potential risk due to their relatively low genetic diversity. Strategies that maintain residual habitat fragments and promote the construction of new refugia are now being formulated. Modelling of the impact of habitat metrics on koala distribution is providing important information that can be used in the rehabilitation of koala refugia. In future these models could be augmented with metrics that describe koala homeostasis to inform local conservation strategies. These considerations are also relevant for the maintenance of other taxa in the wider ecosystem that are also at risk from habitat destruction and climate change.
18
Lunney, Daniel, Eleanor Stalenberg, Truly Santika e Jonathan R. Rhodes. "Extinction in Eden: identifying the role of climate change in the decline of the koala in south-eastern NSW". Wildlife Research 41, n. 1 (2014): 22. http://dx.doi.org/10.1071/wr13054.
Testo completoAbstract (sommario):
Context Reviews of climate change in Australia have identified that it is imposing additional stresses on biodiversity, which is already under threat from multiple human impacts. Aims The present study aimed to determine the contributions of several factors to the demise of the koala in the Eden region in south-eastern New South Wales and, in particular, to establish to what extent climate change may have exacerbated the decline. Methods The study built on several community-based koala surveys in the Eden region since 1986, verified through interviews with survey respondents. Historical records as far back as the late 19th century, wildlife databases and field-based surveys were used to independently validate the community survey data and form a reliable picture of changes in the Eden koala population. Analysis of the community survey data used a logistic model to assess the contribution of known threats to koalas, including habitat loss measured as changes in foliage projective cover, fire, increases in the human population and climate change in the form of changes in temperature and rainfall, to the regional decline of this species. Key results We found a marked, long-term shrinkage in the distribution of the koala across the Eden region. Our modelling demonstrated that a succession of multiple threats to koalas from land use (human population growth and habitat loss) and environmental change (temperature increase and drought) were significant contributors to this decline. Conclusions Climate change, particularly drought and rising temperatures, has been a hitherto hidden factor that has been a major driver of the decline of the koala in the Eden region. Implications Development of strategies to help fauna adapt to the changing climate is of paramount importance, particularly at a local scale.
19
Dennison, S., G. J. Frankham, L. E. Neaves, C. Flanagan, S. FitzGibbon, M. D. B. Eldridge e R. N. Johnson. "Population genetics of the koala (Phascolarctos cinereus) in north-eastern New South Wales and south-eastern Queensland". Australian Journal of Zoology 64, n. 6 (2016): 402. http://dx.doi.org/10.1071/zo16081.
Testo completoAbstract (sommario):
Habitat loss and fragmentation are key threats to local koala (Phascolarctos cinereus) populations. Broad-scale management is suboptimal for koalas because distribution models are not easily generalised across regions. Therefore, it is imperative that data relevant to local management bodies are available. Genetic data provides important information on gene flow and potential habitat barriers, including anthropogenic disturbances. Little genetic data are available for nationally significant koala populations in north-eastern New South Wales, despite reported declines due to urbanisation and habitat loss. In this study, we develop 14 novel microsatellite loci to investigate koala populations in north-eastern New South Wales (Port Macquarie, Coffs Harbour, Tyagarah, Ballina) and south-eastern Queensland (Coomera). All locations were significantly differentiated (FST = 0.096–0.213; FʹST = 0.282–0.582), and this pattern was not consistent with isolation by distance (R2 = 0.228, P = 0.058). Population assignment clustered the more northern populations (Ballina, Tyagarah and Coomera), suggesting contemporary gene flow among these sites. For all locations, low molecular variation among (16%) rather than within (84%) sites suggests historical connectivity. These results suggest that koala populations in north-eastern New South Wales and south-eastern Queensland are experiencing contemporary impediments to gene flow, and highlight the importance of maintaining habitat connectivity across this region.
20
Jiang, Alex, Andrew Tribe e Peter Murray. "The development of an improved scat survey method for koalas (Phascolarctos cinereus)". Australian Journal of Zoology 67, n. 3 (2019): 125. http://dx.doi.org/10.1071/zo20006.
Testo completoAbstract (sommario):
Koala scat surveys are important tools for determining koala presence and distribution in large forested areas where it is impractical to conduct direct observation surveys. However, current scat survey methods are problematic due to lack of either accuracy or feasibility, i.e. they are either biased or very time-consuming in the field. This study aimed to establish a new koala scat survey method with improved accuracy compared with existing methods, and practical in the field. We developed a new Balanced Koala Scat Survey method (BKSS), and evaluated it in the field by analysing scat detectability variations and comparing it with a current survey method, the Spot Assessment Technique (SAT), to determine scat searching accuracy. The results revealed that current methods were biased by assigning consistent searching effort for all trees, because effective searching time to detect the first scat was significantly affected by Koala Activity Level (KAL – the proportion of trees found with scats among all 30 trees in a survey site). Compared with BKSS, SAT tended to yield more false negative outcomes; SAT may miss up to 46% of trees with scats when KAL was low. The application of BKSS is expected to greatly enhance the reliability of koala scat surveys in determining koala distribution and thus improve their conservation management.
21
Phillips, Stephen, e John Callaghan. "Tree species preferences of koalas (Phascolarctos cinereus) in the Campbelltown area south-west of Sydney, New South Wales". Wildlife Research 27, n. 5 (2000): 509. http://dx.doi.org/10.1071/wr98087.
Testo completoAbstract (sommario):
Tree species preferences of a koala population inhabiting a small area of forest and woodland in the Campbelltown area, south-west of Sydney, were investigated over a two-year period. In total, 2499 trees from 45 independent field sites were assessed, with tree species preferences determined on the basis of a comparative analysis of proportional data relating to the presence/absence of koala faecal pellets. The results established that grey gum (Eucalyptus punctata) and blue-leaved stringybark (E. agglomerata) were most preferred by koalas in the study area, but only when growing on shale-based substrates. The preferential utilisation of E. punctata and E. agglomerata on substrates derived from shales, compared with that recorded for the same species on sandstones, suggests that their use by koalas was influenced by differences in nutrient status between substrates. Regression analyses further identified a trend for use of at least one of the preferred species (E. punctata) to be more commonly associated with larger trees. Results are discussed in terms of their relevance to issues of resource availability and the need to reconsider, by way of a hierarchical approach, the use of food trees by koalas generally. The presence of E. punctata and E. agglomerata and their occurrence in conjunction with shale-based substrates are considered to be important limiting factors affecting the present-day distribution and abundance of koalas in the Campbelltown area.
22
Osawa, R., PS Bird, DJ Harbrow, K. Ogimoto e GJ Seymour. "Microbiological Studies of the Intestinal Microflora of the Koala, Phascolarctos-Cinereus .1. Colonization of the Cecal Wall by Tannin-Protein-Complex-Degrading Enterobacteria". Australian Journal of Zoology 41, n. 6 (1993): 599. http://dx.doi.org/10.1071/zo9930599.
Testo completoAbstract (sommario):
The tannin-protein-complex-degrading enterobacterium (T-PCDE), which specifically colonises the caecal wall of the koala, was investigated immunohistologically. Polyclonal antisera were raised against three strains of T-PCDE. Tissue from six koalas was subjected to immunogold staining using a pooled, absorbed antiserum. Numerous T-PCDE cells were observed in the bacterial layer attached to the caecal wall of five of the animals. The distribution pattern of T-PCDE varied: cells were either scattered throughout the bacterial layer or congregated in areas that apparently contained debris of digesta. The sixth animal, which had been treated with oxytetracycline and showed severe loss of body weight, did not have any bacterial layer attached to the caecal wall and did not stain positive for T-PCDE. The evidence suggests a symbiotic association between T-PCDE and the koala; the caecal wall and the wall of the proximal colon were 'strategically' colonised by the bacterium, which may facilitate access, although it is likely to be indirect, for the host animal to the nitrogen moiety liberated from breakdown of tannin-protein complexes.
23
Common, IFB, e M. Horak. "Four new species of Telanepsia Turner (Lepidoptera : Oecophoridae) with larvae feeding on koala and possum scats". Invertebrate Systematics 8, n. 4 (1994): 809. http://dx.doi.org/10.1071/it9940809.
Testo completoAbstract (sommario):
Four species of Telanepsia Turner (Lepidoptera : Oecophoridae : Oecophorinae), T. stockeri, T: scatophila, T. tidbinbilla and T. coprobora, are described as new. The first three have been reared from larvae feeding and pupating within the scats of koalas (Phascolarctos cinereus Goldfuss). Two of these (T. stockeri and T. scatophila) were discovered during a study of koala distribution in the Tantawangalo State Forest, south-eastern New South Wales, and larvae of T. tidbinbilla were collected in koala scats in the Tidbinbilla Nature Reserve, Australian Capital Territory. Larvae of the fourth species (T. coprobora) were found in western Victoria entering from the soil and feeding in the scats of possums (probably the brush-tailed possum, Trichosurus vulpecula Kerr), finally pupating in the soil. Adults of this species have also been collected in southern Queensland, New South Wales and the Australian Capital Territory. Goniobela Turner is established as a new synonym of Telanepsia, and tornospila (Turner) as a new synonym of eucentra (Turner). Six lectotypes are designated and 12 new combinations established.
24
Lollback, Gregory W., J. Guy Castley, Alexa C. Mossaz e Jean-Marc Hero. "Fine-scale changes in spatial habitat use by a low-density koala population in an isolated periurban forest remnant". Australian Mammalogy 40, n. 1 (2018): 84. http://dx.doi.org/10.1071/am16036.
Testo completoAbstract (sommario):
Koala (Phascolarctos cinereus) populations in south-east Queensland are in decline. Although various studies have looked at broad-scale tree preference and habitat quality, there has been little attempt to quantify fine-scale activity shifts from one year to the next or examination of activity at the mesoscale. This study quantified koala activity levels in a 909-ha forest patch at Karawatha Forest Park, in south Brisbane. The Spot Assessment Technique was used to quantify activity and tree selection on 33 long-term monitoring plots in 2009 and 2010. In total, 843 trees were searched and koala pellets were found underneath 34 and 47 trees in 2009 and 2010, respectively. A higher proportion of pellets was found underneath Eucalyptus tindaliae and E. fibrosa and there was weak selection for larger trees. A low occurrence of revisits and a minor shift in activity distribution from 2009 to 2010 indicate that the koala population exists at a low density. Rapid declines in koala populations are occurring in primary habitats. Hence, stable low-density koala populations are important for maintaining genetic diversity and connectivity in fragmented urban landscapes.
25
Zee, Yeng Peng, William V. Holt, Camryn D. Allen, Vere Nicolson, Michelle Burridge, Allan Lisle, Frank N. Carrick e Steve D. Johnston. "Effects of cryopreservation on mitochondrial function and heterogeneity, lipid raft stability and phosphatidylserine translocation in koala (Phascolarctos cinereus) spermatozoa". Reproduction, Fertility and Development 19, n. 7 (2007): 850. http://dx.doi.org/10.1071/rd07084.
Testo completoAbstract (sommario):
Koala sperm mitochondria were examined by cryomicroscopy using the fluorescent probe JC-1, which distinguishes high (red) and low (green) mitochondrial membrane potential (MMP). At normal body temperature, ~70% of live and untreated spermatozoa exhibited high MMP whereas <3% of live untreated spermatozoa exhibited low potential. A third class, in which single midpieces contained mixed mitochondrial populations, was also detected. Heterogeneity was noted in the level of MMP between individual koalas, individual spermatozoa and even between mitochondrial gyres within single midpieces. MMP of the live sperm population was not significantly affected by glycerol but was suppressed by freezing and thawing treatments. After thawing, MMP declined significantly during rewarming, especially as the temperature increased from 5 to 35°C. The distribution of the ganglioside GM1 was examined using fluorescent-labelled cholera toxin B. In fresh, untreated koala spermatozoa GM1 was detected on the head and midpiece, but not on the principal piece. No significant redistribution of GM1 was observed after chilling and cryotreatment. Phosphatidylserine translocation across the plasma membrane was examined using fluorescent-labelled annexin V. Few fresh spermatozoa exhibited phosphatidylserine translocation (~1%); this was not increased by chilling or cryopreservation, thus implying that cryotreatment had little effect on plasma membrane lipid asymmetry.
26
Alfano, Niccolò, Johan Michaux, Serge Morand, Ken Aplin, Kyriakos Tsangaras, Ulrike Löber, Pierre-Henri Fabre et al. "Endogenous Gibbon Ape Leukemia Virus Identified in a Rodent (Melomys burtoni subsp.) from Wallacea (Indonesia)". Journal of Virology 90, n. 18 (6 luglio 2016): 8169–80. http://dx.doi.org/10.1128/jvi.00723-16.
Testo completoAbstract (sommario):
ABSTRACTGibbon ape leukemia virus (GALV) and koala retrovirus (KoRV) most likely originated from a cross-species transmission of an ancestral retrovirus into koalas and gibbons via one or more intermediate as-yet-unknown hosts. A virus highly similar to GALV has been identified in an Australian native rodent (Melomys burtoni) after extensive screening of Australian wildlife. GALV-like viruses have also been discovered in several Southeast Asian species, although screening has not been extensive and viruses discovered to date are only distantly related to GALV. We therefore screened 26 Southeast Asian rodent species for KoRV- and GALV-like sequences, using hybridization capture and high-throughput sequencing, in the attempt to identify potential GALV and KoRV hosts. Only the individuals belonging to a newly discovered subspecies ofMelomysburtonifrom Indonesia were positive, yielding an endogenous provirus very closely related to a strain of GALV. The sequence of the critical receptor domain for GALV infection in the IndonesianM. burtonisubsp. was consistent with the susceptibility of the species to GALV infection. The second record of a GALV inM. burtoniprovides further evidence thatM. burtoni, and potentially other lineages within the widespread subfamilyMurinae, may play a role in the spread of GALV-like viruses. The discovery of a GALV in the most western part of the Australo-Papuan distribution ofM. burtoni, specifically in a transitional zone between Asia and Australia (Wallacea), may be relevant to the cross-species transmission to gibbons in Southeast Asia and broadens the known distribution of GALVs in wild rodents.IMPORTANCEGibbon ape leukemia virus (GALV) and the koala retrovirus (KoRV) are very closely related, yet their hosts neither are closely related nor overlap geographically. Direct cross-species infection between koalas and gibbons is unlikely. Therefore, GALV and KoRV may have arisen via a cross-species transfer from an intermediate host whose range overlaps those of both gibbons and koalas. Using hybridization capture and high-throughput sequencing, we have screened a wide range of rodent candidate hosts from Southeast Asia for KoRV- and GALV-like sequences. Only aMelomysburtonisubspecies from Wallacea (Indonesia) was positive for GALV. We report the genome sequence of this newly identified GALV, the critical domain for infection of its potential cellular receptor, and its phylogenetic relationships with the other previously characterized GALVs. We hypothesize thatMelomysburtoni, and potentially related lineages with an Australo-Papuan distribution, may have played a key role in cross-species transmission to other taxa.
27
Melzer, Alistair, Frank Carrick, Peter Menkhorst, Daniel Lunney e Barbara ST John. "Overview, Critical Assessment, and Conservation Implications of Koala Distribution and Abundance". Conservation Biology 14, n. 3 (giugno 2000): 619–28. http://dx.doi.org/10.1046/j.1523-1739.2000.99383.x.
Testo completo
28
Knott, Tiffany, Daniel Lunney, Dionne Coburn e John Callaghan. "An ecological history of Koala habitat in Port Stephens Shire and the Lower Hunter on the Central Coast of New South Wales, 1801-1998". Pacific Conservation Biology 4, n. 4 (1998): 354. http://dx.doi.org/10.1071/pc980354.
Testo completoAbstract (sommario):
This paper describes the vegetation of Port Stephens Shire and environs at the time of European settlement, defines the sequence of vegetation clearance since that time, and estimates the extent to which the pre-European vegetation represented Koala habitat. A study of historical records, newspapers, documents and reports was undertaken in conjunction with interviews with long-standing Port Stephens residents. The historical records show that Koalas were widespread and common during early settlement. Reconstruction of the original vegetation was based on descriptions by early explorers and settlers from the early 1800s, when settlement commenced. Most of the land on either side of the Hunter River was vegetated by Shrubby Tall Open Forest intermingling with either Open Swamp Forest, or VineFern Closed Forest, or cedar brush. The first area to be settled was the alluvial land on the banks of the rivers where the soil was fertile and well watered. Settlement proceeded rapidly in the western part of the Shire from the early 1800s, concentrating on the Lower Hunter and Williams Rivers, but not progressing to the east until much later (mid to late 1800s). The historical record was sufficiently detailed to allow reconstruction of Koala habitat distribution at the time of settlement. Ecological history is now emerging as a discipline that has far more than curiosity value. It can provide the essential framework for conserving and restoring those landscapes exploited in the first century of European settlement.
29
Munks, SA, R. Corkrey e WJ Foley. "Characteristics of Arboreal Marsupial Habitat in the Semi-Arid Woodlands of Northern Queensland." Wildlife Research 23, n. 2 (1996): 185. http://dx.doi.org/10.1071/wr9960185.
Testo completoAbstract (sommario):
The distribution of the koala (Phascolarctos cinereus) and the common brushtail possum (Trichosurus vulpecula) within the Prairie-Torrens Creek Alluvials province of the Desert Upland region of north-western Queensland was examined. The optimum habitat for each species as indicated by the occurrence of faecal pellet groups was found to be that associated with creek-lines. However, other land types were also used by each species to varying degrees. The relationship between various habitat variables and pellet group counts was investigated using Multiple regression and a Generalised linear model. Proximity to creek-bed, total basal area of trees, species richness and Acacia basal area (negative) best explained the occurrence of koalas. Proximity to creek-bed, Acacia basal area (negative), total basal area of trees, and available water (negative) best explained the occurrence of brushtail possums. In contrast to studies of arboreal species in the moist-south-eastern forests of Australia no relationship was found between foliar nutrient concentrations and the occurrence of koalas or brushtail possums. However, a significant relationship was found between leaf water concentration and the occurrence of koalas. It is suggested that water availability is the paramount factor defining preferred arboreal habitat in arid and semi-arid woodlands.
30
Davies, Nicole Ashley, Galina Gramotnev, Clive McAlpine, Leonie Seabrook, Greg Baxter, Daniel Lunney, Jonathan R. Rhodes e Adrian Bradley. "Physiological Stress in Koala Populations near the Arid Edge of Their Distribution". PLoS ONE 8, n. 11 (12 novembre 2013): e79136. http://dx.doi.org/10.1371/journal.pone.0079136.
Testo completo
31
Burach, F., A. Pospischil, J. Hanger, J. Loader, T. Pillonel, G. Greub e N. Borel. "Chlamydiales in the Koala (Phascolarctos cinereus): Organ Distribution and Related Histopathological Findings". Journal of Comparative Pathology 152, n. 1 (gennaio 2015): 54. http://dx.doi.org/10.1016/j.jcpa.2014.10.056.
Testo completo
32
Zabaras, R., B. J. Richardson e S. G. Wyllie. "Evolution in the suite of semiochemicals secreted by the sternal gland of Australian marsupials". Australian Journal of Zoology 53, n. 4 (2005): 257. http://dx.doi.org/10.1071/zo04070.
Testo completoAbstract (sommario):
The nature and distribution of the components, and evolution of the suite of compounds, secreted by the sternal gland of marsupials were studied. Individuals from nine families (18 species) of marsupials and from the echidna were sampled over an 18-month period. The assay system used gas chromatography/mass spectrometry and utilised thermal desorption with cryofocusing. Parsimony analysis, constrained by an assumed phylogeny, was used to examine the evolution of the suite of compounds detected. Large interspecies variation in secretion composition was observed with acetic acid, short-chain (C6–C10) aldehydes, long-chain (>C15) hydrocarbons and 1,1-bis-(p-tolyl)-ethane being constituents of the secretion of most species. The suite of compounds, however, varied from three compounds in the yellow-bellied and feathertail gliders to 41 in the koala. The most complex suites of compounds were found in the brown antechinus, red kangaroo, tammar wallaby and koala. Radical differences were observed between the secretions of related species (for example, brown antechinus and mulgara, tammar and parma wallabies, wombat and koala). Compounds appeared and disappeared repeatedly across the phylogeny. No compound constituted a synapomorphy for the Australian marsupials and only one compound was considered a synapomorphy for the Diprotodontia.
33
Dissanayake, Ravi Bandara, Mark Stevenson, Rachel Allavena e Joerg Henning. "Predicting koala (Phascolarctos cinereus) distribution from incidental sighting data in South-East Queensland, Australia". Global Ecology and Conservation 28 (agosto 2021): e01662. http://dx.doi.org/10.1016/j.gecco.2021.e01662.
Testo completo
34
Burach, Fabienne, Andreas Pospischil, Jon Hanger, Jo Loader, Trestan Pillonel, Gilbert Greub e Nicole Borel. "Chlamydiaceae and Chlamydia-like organisms in the koala (Phascolarctos cinereus)—Organ distribution and histopathological findings". Veterinary Microbiology 172, n. 1-2 (agosto 2014): 230–40. http://dx.doi.org/10.1016/j.vetmic.2014.04.022.
Testo completo
35
Timmermans, S. H., M. Mommers, J. S. Gubbels, S. P. J. Kremers, A. Stafleu, C. D. A. Stehouwer, M. H. Prins, J. Penders e C. Thijs. "Maternal smoking during pregnancy and childhood overweight and fat distribution: the KOALA Birth Cohort Study". Pediatric Obesity 9, n. 1 (30 gennaio 2013): e14-e25. http://dx.doi.org/10.1111/j.2047-6310.2012.00141.x.
Testo completo
36
Myers, G. S. A., S. A. Mathews, M. Eppinger, C. Mitchell, K. K. O'Brien, O. R. White, F. Benahmed et al. "Evidence that Human Chlamydia pneumoniae Was Zoonotically Acquired". Journal of Bacteriology 191, n. 23 (11 settembre 2009): 7225–33. http://dx.doi.org/10.1128/jb.00746-09.
Testo completoAbstract (sommario):
ABSTRACT Zoonotic infections are a growing threat to global health. Chlamydia pneumoniae is a major human pathogen that is widespread in human populations, causing acute respiratory disease, and has been associated with chronic disease. C. pneumoniae was first identified solely in human populations; however, its host range now includes other mammals, marsupials, amphibians, and reptiles. Australian koalas (Phascolarctos cinereus) are widely infected with two species of Chlamydia, C. pecorum and C. pneumoniae. Transmission of C. pneumoniae between animals and humans has not been reported; however, two other chlamydial species, C. psittaci and C. abortus, are known zoonotic pathogens. We have sequenced the 1,241,024-bp chromosome and a 7.5-kb cryptic chlamydial plasmid of the koala strain of C. pneumoniae (LPCoLN) using the whole-genome shotgun method. Comparative genomic analysis, including pseudogene and single-nucleotide polymorphism (SNP) distribution, and phylogenetic analysis of conserved genes and SNPs against the human isolates of C. pneumoniae show that the LPCoLN isolate is basal to human isolates. Thus, we propose based on compelling genomic and phylogenetic evidence that humans were originally infected zoonotically by an animal isolate(s) of C. pneumoniae which adapted to humans primarily through the processes of gene decay and plasmid loss, to the point where the animal reservoir is no longer required for transmission.
37
Sullivan, B. J., G. S. Baxter e A. T. Lisle. "Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. III. Broad-scale patterns of habitat use". Wildlife Research 30, n. 6 (2003): 583. http://dx.doi.org/10.1071/wr02036.
Testo completoAbstract (sommario):
To date there have been few quantitative studies of the distribution of, and relative habitat utilisation by, koalas in the mulgalands of Queensland. To examine these parameters we applied habitat-accessibility and relative habitat-utilisation indices to estimates of faecal pellet density sampled at 149 sites across the region. Modelling the presence of pellets using logistic regression showed that the potential range of accessible habitats and relative habitat use varied greatly across the region, with rainfall being probably the most important determinant of distribution. Within that distribution, landform and rainfall were both important factors affecting habitat preference. Modelling revealed vastly different probabilities of finding a pellet under trees depending on the tree species, canopy size, and location within the region.
38
Shabani, Farzin, Mohsen Ahmadi, Katharina J. Peters, Simon Haberle, Antoine Champreux, Frédérik Saltré e Corey J. A. Bradshaw. "Climate‐driven shifts in the distribution of koala‐browse species from the Last Interglacial to the near future". Ecography 42, n. 9 (27 giugno 2019): 1587–99. http://dx.doi.org/10.1111/ecog.04530.
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39
McAlpine, C. A., J. R. Rhodes, M. E. Bowen, D. Lunney, J. G. Callaghan, D. L. Mitchell e H. P. Possingham. "Can multiscale models of species’ distribution be generalized from region to region? A case study of the koala". Journal of Applied Ecology 45, n. 2 (aprile 2008): 558–67. http://dx.doi.org/10.1111/j.1365-2664.2007.01431.x.
Testo completo
40
Cristescu, Romane H., Klara Goethals, Peter B. Banks, Frank N. Carrick e Céline Frère. "Experimental Evaluation of Koala Scat Persistence and Detectability with Implications for Pellet-Based Fauna Census". International Journal of Zoology 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/631856.
Testo completoAbstract (sommario):
Establishing species distribution and population trends are basic requirements in conservation biology, yet acquiring this fundamental information is often difficult. Indirect survey methods that rely on fecal pellets (scats) can overcome some difficulties but present their own challenges. In particular, variation in scat detectability and decay rate can introduce biases. We studied how vegetation communities affect the detectability and decay rate of scats as exemplified by koalasPhascolarctos cinereus: scat detectability was highly and consistently dependent on ground layer complexity (introducing up to 16% non-detection bias); scat decay rates were highly heterogeneous within vegetation communities; exposure of scats to surface water and rain strongly accelerated scat decay rate and finally, invertebrates were found to accelerate scat decay rate markedly, but unpredictably. This last phenomenon may explain the high variability of scat decay rate within a single vegetation community. Methods to decrease biases should be evaluated when planning scat surveys, as the most appropriate method(s) will vary depending on species, scale of survey and landscape characteristics. Detectability and decay biases are both stronger in certain vegetation communities, thus their combined effect is likely to introduce substantial errors in scat surveys and this could result in inappropriate and counterproductive management decisions.
41
Piltz, Ross O. "Accurate data processing for neutron Laue diffractometers". Journal of Applied Crystallography 51, n. 3 (25 maggio 2018): 635–45. http://dx.doi.org/10.1107/s1600576718005058.
Testo completoAbstract (sommario):
The factors affecting the accuracy of structural refinements from image-plate neutron Laue diffractometers are analysed. From this analysis, an improved data-processing method is developed which optimizes the intensity corrections for exposure scaling, wavelength distribution, absorption and extinction corrections, and the wavelength/spatial/time dependence of the image-plate detector efficiencies. Of equal importance is an analysis of the sources of uncertainty in the final corrected intensities, without which bias of the merged intensities occurs, due to the dominance of measurements with small statistical errors though potentially large systematic errors. A new aspect of the impact of detector crosstalk on the counting statistics of area detectors is reported and shown to be significant for the case of neutron Laue diffraction. These methods have been implemented in software which processes data from the KOALA instrument at ANSTO and the now decommissioned VIVALDI instrument at ILL (Grenoble, France). A comparison with earlier data-analysis methods shows a significant improvement in accuracy of the refined structures.
42
Jurskis, Vic, Alan Douch, Ken McCray e Jim Shields. "A playback survey of the koala,Phascolarctos cinereus, and a review of its distribution in the Eden Region of south-eastern New South Wales". Australian Forestry 64, n. 4 (gennaio 2001): 226–31. http://dx.doi.org/10.1080/00049158.2001.10676193.
Testo completo
43
Löber, Ulrike, Matthew Hobbs, Anisha Dayaram, Kyriakos Tsangaras, Kiersten Jones, David E. Alquezar-Planas, Yasuko Ishida et al. "Degradation and remobilization of endogenous retroviruses by recombination during the earliest stages of a germ-line invasion". Proceedings of the National Academy of Sciences 115, n. 34 (6 agosto 2018): 8609–14. http://dx.doi.org/10.1073/pnas.1807598115.
Testo completoAbstract (sommario):
Endogenous retroviruses (ERVs) are proviral sequences that result from colonization of the host germ line by exogenous retroviruses. The majority of ERVs represent defective retroviral copies. However, for most ERVs, endogenization occurred millions of years ago, obscuring the stages by which ERVs become defective and the changes in both virus and host important to the process. The koala retrovirus, KoRV, only recently began invading the germ line of the koala (Phascolarctos cinereus), permitting analysis of retroviral endogenization on a prospective basis. Here, we report that recombination with host genomic elements disrupts retroviruses during the earliest stages of germ-line invasion. One type of recombinant, designated recKoRV1, was formed by recombination of KoRV with an older degraded retroelement. Many genomic copies of recKoRV1 were detected across koalas. The prevalence of recKoRV1 was higher in northern than in southern Australian koalas, as is the case for KoRV, with differences in recKoRV1 prevalence, but not KoRV prevalence, between inland and coastal New South Wales. At least 15 additional different recombination events between KoRV and the older endogenous retroelement generated distinct recKoRVs with different geographic distributions. All of the identified recombinant viruses appear to have arisen independently and have highly disrupted ORFs, which suggests that recombination with existing degraded endogenous retroelements may be a means by which replication-competent ERVs that enter the germ line are degraded.
44
Forbes, Duncan A. "Reverse engineering the Milky Way". Monthly Notices of the Royal Astronomical Society 493, n. 1 (29 gennaio 2020): 847–54. http://dx.doi.org/10.1093/mnras/staa245.
Testo completoAbstract (sommario):
ABSTRACT The ages, metallicities, alpha-elements, and integrals of motion of globular clusters (GCs) accreted by the Milky Way from disrupted satellites remain largely unchanged over time. Here we have used these conserved properties in combination to assign 76 GCs to five progenitor satellite galaxies – one of which we dub the Koala dwarf galaxy. We fit a leaky-box chemical enrichment model to the age–metallicity distribution of GCs, deriving the effective yield and the formation epoch of each satellite. Based on scaling relations of GC counts we estimate the original halo mass, stellar mass, and mean metallicity of each satellite. The total stellar mass of the five accreted satellites contributed around 109 M⊙ in stars to the growth of the Milky Way but over 50 per cent of the Milky Way’s GC system. The five satellites formed at very early times and were likely accreted 8–11 Gyr ago, indicating rapid growth for the Milky Way in its early evolution. We suggest that at least three satellites were originally nucleated, with the remnant nucleus now a GC of the Milky Way. 11 GCs are also identified as having formed ex situ but could not be assigned to a single progenitor satellite.
45
Calin, V. L., G. E. D. Petrescu, M. Mihailescu, F. M. Brehar, M. Lisievici, B. Comanescu, N. Tarba, M. R. Gorgan, T. Savopol e M. G. Moisescu. "P04.17 Differential diagnosis of gliomas using Digital Holographic Microscopy". Neuro-Oncology 21, Supplement_3 (agosto 2019): iii32—iii33. http://dx.doi.org/10.1093/neuonc/noz126.112.
Testo completoAbstract (sommario):
Abstract BACKGROUND The clinical course and prognostic of gliomas depend on the tumor histological and molecular features. The histopathological diagnosis requests well-trained specialists and multi-step operational procedures for sample preparation. Faster and more objective protocols should be implemented in support of pathologists. The Quantitative Phase Imaging based methods are biologically proved to be efficient in revealing, without any labeling, important characteristics of the living specimens having different structural complexity. We used Digital Holographic Microscopy (DHM) to acquire QPIs and to analyze glioma samples in order to discriminate glioma tissues of various malignancy grades. MATERIAL AND METHODS Grade II glioma (GM) and grade IV glioblastoma (GBM) tissues were collected from patients who underwent surgery. For each sample, two consecutive slices were fixed with formalin, embedded in paraffin and cut at 4 µm thickness. One slice was stained using hematoxylin and eosin (H&E) and the other slice was left unstained. The pathologist diagnosed H&E slides as GM or GBM and the corresponding unstained slides were accordingly labeled. Holograms of unstained sections were acquired using a LyncéeTec DHM®-R1000 digital holographic microscope (at 664.5 nm). QPIs were reconstructed using the Koala dedicated software, and then the distribution of the phase shift values in the image was characterized by various statistical parameters (mean, variance, kurtosis, skewness, energy, entropy). RESULTS A total of 78 images were analyzed, 33 for grade II gliomas and 45 for grade IV glioblastomas, the areas being randomly selected, as the tissue is highly homogeneous. Lower values of Mean, Variance and Energy and higher values of Kurtosis and Entropy were found for GM compared to GBM (Mann-Whitney test was performed for proofing the statistically significance). No statistical difference was observed for Skewness. As the thickness of the samples was constant, variations of these parameters may be attributed to different distributions of the refractive index within the samples, which in turn is directly related to the protein content and structural features of the tissue. CONCLUSION The analyze of unstained biopsies of glioma tumors based on DHM could be used for faster and more accurate diagnosis, offering efficient optical markers to distinguish between levels of malignancy with high statistical confidence. Our findings can be further exploited for automatic evaluation and classification of malignant tissues, parameters provided by QPIs being used as classifiers for a supervised machine algorithm. This method can be adapted for fresh samples, being thus a promising method for intraoperative diagnostic.
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Wilmott, Lachlan, Dympna Cullen, George Madani, Martin Krogh e Kylie Madden. "Are koalas detected more effectively by systematic spotlighting or diurnal searches?" Australian Mammalogy 41, n. 1 (2019): 157. http://dx.doi.org/10.1071/am18006.
Testo completoAbstract (sommario):
Koalas (Phascolarctos cinereus) are difficult to detect due to their cryptic nature, occurrence at low densities and broad distribution. We compare the relative effectiveness of two common, direct survey techniques used to detect koalas: spotlighting and diurnal searches. Seventy-six 2-ha sites were surveyed using both spotlighting and diurnal searching. Each site was surveyed for 0.5 person-hours, such that search area and effort were equal. In this study, spotlighting was found to be 3.25 times more effective at detecting koalas than day searches. Therefore, where access and terrain allows, spotlighting surveys offer a significant advantage over diurnal searches in the detection of koalas.
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Codjia, Sylvie, Augustin Aoudji, Kourouma Koura e Jean Cossi Ganglo. "Systèmes Agroforestiers A Garcinia Kola Heckel Au Sud-Est Du Bénin : Distribution Géographique, Connaissances Endogènes Et Retombées Financières". European Scientific Journal, ESJ 14, n. 12 (30 aprile 2018): 188. http://dx.doi.org/10.19044/esj.2018.v14n12p188.
Testo completoAbstract (sommario):
This study was carried out in three districts (Avrankou, Adjarra, and Ifangni) of south-eastern Benin, and aimed to analyze the socio-economic and ethnobotanical importance of Garcinia kola Heckel, in order to contribute to their sustainable management. Focus groups were conducted with three groups, composed of 10 owners of G. kola per district each and the result showed that Garcinia kola Heckel became extinct in their naturally occurring state in Benin. Besides, a survey was conducted among 140 owners of G. kola randomly selected in the study area. The results showed that the average number of G. kola feet per owner varies between 3 and 4, and the annual income generated from seeds marketing by an owner is XOF 1036000 in Adjarra district, XOF 356250 in Avrankou district, and XOF 290892 in Ifangni district. Furthermore, the ethnobotanical study showed that G. kola organs are well known and used by local people for medicine, food (for both humans and animals), commercial, spiritual purpose, and for timber and shading. The medicinal use was the most widespread with a diversity of uses (UD = 0.64 in Adjarra, UD = 0.61 in Avrankou and UD = 0.68 in Ifangni). The old men held more knowledge about the use of various organs of the species (ID = 0.91, IE = 0.91), while young women hold less knowledge (ID = 0.20, IE = 0.20). The seeds are the most common part used regardless of the district considered.
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Logan, M., e G. D. Sanson. "The effects of lactation on the feeding behaviour and activity patterns of free-ranging female koalas (Phascolarctos cinereus Goldfuss)". Australian Journal of Zoology 51, n. 4 (2003): 415. http://dx.doi.org/10.1071/zo03017.
Testo completoAbstract (sommario):
The free-ranging feeding behaviour and activity patterns of three lactating and two non-lactating female koalas (Phascolarctos cinereus) were investigated using acoustically sensitive radio-telemetry. Lactating females were found to consume more leaf material, masticate more per leaf and at a greater rate, and perform more ingestive and mercyism mastications per 24 h than non-lactating females. Results suggest than female koalas are 'income breeders' that compensate for the higher energetic demands of lactation by increasing intake and, to a lesser degree, investing more in each mouthful so as to produce a shift in digesta particle size distribution in favour of more finer particles. Compared with non-lactating females, lactating female koalas were also found to spend more time moving within trees, feeding per 24 h and per bout, and less time resting and sleeping per 24 h, although the proportion of active time spent feeding was similar (~80%). This implies that female koalas adopt a 'time minimizing strategy whereby activity budgets respond to current requirements. Lactation-compensation mechanisms are compared with those reported for koalas with high tooth wear, and the capacity of aging female koalas to compensate for lactation are discussed.
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Nartshuk, Emilia. "A revision of grassflies of the tribe Chloropini (Diptera, Chloropidae) of Finland, Estonia and North-West Russia". Entomologica Fennica 9, n. 3 (1 settembre 1998): 153–83. http://dx.doi.org/10.33338/ef.83979.
Testo completoAbstract (sommario):
Collections of Chloropini: genera Chlorops Meigen, Epichlorops Becker and Melanum Becker from Finland, Estonia, Karelia and the Kola Peninsula are revised. 24 species are recorded from Finland, 21 for Karelia and 8 for the Kola Peninsula. Three species of Chlorops for Finland, 3 for Estonia, 21 for Karelia and 8 for Murmansk oblast are recorded for the first time. The northern limits of distribution of Chlorops species are compared with the isopleths of effective temperature sums. A correlation between the distribution of Chlorops species northward and eastward in the Palaearctic is discussed. New synonymy: Chlorops laevicollis Becker, 1910 = Oscinis scutellaris Zetterstedt, 1848 is established. The lectotype of Chlorops freyi Duda, 1933 is designated. A key to the known species from Finland, Estonia, Karelia, the Kola Peninsula and St. Petersburg region, maps of records in Finland, Karelia and the Kola Peninsula for all species, and an illustration of male genitalia for some species are provided.
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Rovenchak, Andrij. "Telling apartFelidaeandUrsidaefrom the distribution of nucleotides in mitochondrial DNA". Modern Physics Letters B 32, n. 05 (20 febbraio 2018): 1850057. http://dx.doi.org/10.1142/s0217984918500574.
Testo completoAbstract (sommario):
Rank–frequency distributions of nucleotide sequences in mitochondrial DNA are defined in a way analogous to the linguistic approach, with the highest-frequent nucleobase serving as a whitespace. For such sequences, entropy and mean length are calculated. These parameters are shown to discriminate the species of the Felidae (cats) and Ursidae (bears) families. From purely numerical values we are able to see in particular that giant pandas are bears while koalas are not. The observed linear relation between the parameters is explained using a simple probabilistic model. The approach based on the non-additive generalization of the Bose distribution is used to analyze the frequency spectra of the nucleotide sequences. In this case, the separation of families is not very sharp. Nevertheless, the distributions for Felidae have on average longer tails comparing to Ursidae.