Predation by feral cats key to the failure of a long-term reintroduction of the western barred bandicoot (Perameles bougainville)

2016 ◽  
Vol 43 (1) ◽  
pp. 38 ◽  
Author(s):  
Jeff Short
Keyword(s):  
Prey Species ◽  
Local Extinction ◽  
Contributing Factors ◽  
Feral Cats ◽  
European Rabbits ◽  
Threatening Processes ◽  
The Impact ◽  
Methods Of Control

Context Reintroduction of endangered species potentially places them back in contact with putative factors of historical decline, inadvertently providing the opportunity to evaluate their impact. Aims To monitor the long-term progress of a population of western barred bandicoot reintroduced to mainland Australia and to assess factors involved in its eventual local extinction. Methods Bandicoots were reintroduced from offshore Dorre Island to the nearby mainland peninsula of Heirisson Prong in 1995. The narrow neck of the peninsula was fenced to exclude foxes and feral cats from a 1200 ha area, but the area was subject to periodic incursions. There was parallel management of a confined but unsupported population in an in situ 17-ha predator refuge. Bandicoots were assessed for abundance, body condition and reproduction two to four times annually between 1995 and 2010. In addition, perceived threatening processes (drought, disease and the abundance of cats, foxes and rabbits) were monitored. Key results Bandicoots became well established at the site, spreading to all available habitat. Numbers fluctuated strongly, peaking at ~250 in 1999 and then declining to apparent local extinction (with subsequent re-establishment from the refuge), and at ~470 animals in 2006, followed again by extinction. Conclusions Predation by feral cats was implicated as the primary cause of both free-range extinctions and the eventual elimination of all bandicoots from the predator refuge. Other contributing factors in one or more of the declines were a reduction in reproduction and recruitment in bandicoots during a one-in-100-year drought, the impact of overabundant European rabbits on vegetation used by bandicoots for nesting shelter and brief fox incursions at key times. Implications Existing methods of control of feral cats are rendered ineffective in the presence of abundant and diverse native fauna and abundant exotic species (particularly European rabbits). In addition, episodic drought in arid Australia intensifies the impact of predation by restricting reproduction of prey species. These factors hamper the attempts of conservation managers to re-establish vulnerable species at sites other than those with the infrastructure and/or management intensity to largely exclude exotic predators (and preferably European rabbits) over the long-term.

The Use of Laboratory-Measured and Strain-Gauge Backcalculated Asphalt Stiffness for Rutting Performance Prediction

2019 ◽  
Vol 2673 (3) ◽  
pp. 323-333
Author(s):  
Erdem Coleri ◽  
John T. Harvey
Keyword(s):  
Performance Prediction ◽  
Strain Gauge ◽  
Asphalt Concrete ◽  
Laboratory Tests ◽  
Concrete Materials ◽  
Long Term Performance ◽  
Term Performance ◽  
The Impact

Laboratory tests are conducted with asphalt concrete materials to determine the expected in-situ performance. In addition, laboratory test results are commonly used in mechanistic-empirical design methods for material characterization to improve the predictive accuracy of the models. However, the effectiveness of laboratory tests in characterizing the long-term performance of asphalt concrete materials needs to be validated to be able to use the results for pavement design and long-term performance prediction. Inaccurate performance characterization and prediction can directly affect the decision-making process for pavement maintenance, rehabilitation, and reconstruction and result in unexpected early failures in the field. The major objective of this study is to determine the impact of using laboratory-measured asphalt stiffness on the prediction accuracy of mechanistic-empirical models. In addition, the effect of using linear-elastic modeling assumptions (layered elastic theory) and neglecting the nonlinearity of pavement response at high load levels (and/or at high strain levels for weaker structures) on the predicted rutting performance was determined. In this study, the effectiveness of the use of laboratory asphalt stiffness tests for in-situ asphalt stiffness characterization was determined by comparing the rutting performance predicted using laboratory-measured stiffness to rutting predicted using strain-gauge backcalculated stiffness. It was determined that laboratory tests are able to characterize the in-situ stiffness characteristics of the asphalt mix used in this study and the stiffness characterization process suggested in this study can provide reliable rutting performance predictions. Results of this study are only applicable to tested rubberized asphalt concrete mixtures.

Belastung von Patienten und Gesundheitssystem durch Pleuraverweildrainage zur Versorgung chronischer Pleuraergüsse

2019 ◽  
Vol 7 (2) ◽  
pp. 84-85
Author(s):  
Axel Tobias Kempa
Keyword(s):  
Length Of Hospital Stay ◽  
Chest Drain ◽  
Long Term Outcomes ◽  
Talc Pleurodesis ◽  
In Situ Methods ◽  
Hospital Visits ◽  
The Impact

Background: Indwelling pleural catheters (IPC) offer an alternative to talc pleurodesis in recurrent effusion, especially in patients wishing to avoid hospitalization. Two randomized trials have demonstrated reduced time in hospital using IPCs versus talc pleurodesis in malignant pleural effusion (MPE). However, the impact of IPCs on hospital services and patients has not been well studied. Objectives: To analyze long-term outcomes of IPCs and understand the hospital burden in terms of requirement for hospital visits and contacts with healthcare, while the IPC was in situ. Methods: IPC insertions in a tertiary pleural center were analyzed retrospectively. Reviews of patients with IPCs in situ considered «additional» to routine clinical follow-up were defined pre-hoc. Results: A total of 202 cases were analyzed: 89.6% MPE group (n = 181) and 10.4% non-MPE group (n = 21). There were a median 3.0 (interquartile range [IQR] 3) and 2.0 (IQR 2) ipsilateral pleural procedures prior to each IPC insertion in non-MPE and MPE groups, respectively (p = 0.26), and a mean 1.3 (SD 1.7) planned IPC-related outpatient follow-up visits per patient. There were 2 (9.5%) and 14 (7.7%) IPC-related infections in non-MPE and MPE groups, respectively. Four (19.0%) and 44 (24.3%) patients required additional IPC-related reviews in non-MPE and MPE groups, respectively (p = 0.6), and these occurred within 250 days post IPC insertion. Conclusions: Although IPCs decrease initial length of hospital stay compared to talc pleurodesis via chest drain, IPCs are associated with significant hospital-visit burden, in addition to planned visits and regular home IPC drainages. IPC-using services need to be prepared for this additional work to run an IPC service effectively.

scholarly journals Homologous chromosomes in asexual rotifer Adineta vaga suggest automixis

2020 ◽  
Author(s):  
Paul Simion ◽  
Jitendra Narayan ◽  
Antoine Houtain ◽  
Alessandro Derzelle ◽  
Lyam Baudry ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Genome Structure ◽  
Meiotic Pairing ◽  
Chromosome Conformation ◽  
Homologous Chromosomes ◽  
Ancient Asexual ◽  
High Doses ◽  
The Impact

ABSTRACTThe several hundreds of species of bdelloid rotifers are notorious because they represent an ancient clade comprising only asexual lineages1. Moreover, most bdelloid species have the ability to withstand complete desiccation and high doses of ionizing radiation, being able to repair their DNA after massive genome breakage2. To better understand the impact of long-term asexuality and DNA breakage on genome evolution, a telomere-to-tolemere reference genome assembly of a bdelloid species is critical3, 4. Here we present the first, high quality chromosome-scale genome assembly for the bdelloid A. vaga validated using three complementary assembly procedures combined with chromosome conformation capture (Hi-C) data. The different assemblies reveal the same genome architecture and using fluorescent in situ hybridization (FISH), we demonstrate that the A. vaga genome is composed of six pairs of homologous chromosomes, compatible with meiosis. Moreover, the synteny between homoeologous (or ohnologous) chromosomes is also preserved, confirming their paleotetraploidy. The diploid genome structure of A. vaga and the presence of very long homozygous tracts show that recombination between homologous chromosomes occurs in this ancient asexual scandal, either during DSB repair or during meiotic pairing. These homozygosity tracts are mainly observed towards the chromosome ends in the clonal A. vaga suggesting signatures of a parthenogenetic mode of reproduction equivalent to central fusion automixis, in which homologous chromosomes are not segregated during the meiotic division.

scholarly journals Damage mechanisms and embrittlement kinetics in a β-rich Ti 17 alloy after long term aging

2020 ◽  
Vol 321 ◽  
pp. 06008
Author(s):  
Layla SASAKI ◽  
Gilbert HENAFF ◽  
Mandana ARZAGHI ◽  
Patrick VILLECHAISE ◽  
Samuel HEMERY ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Detrimental Effect ◽  
Damage Tolerance ◽  
Tensile Tests ◽  
Mechanical Resistance ◽  
Damage Mechanisms ◽  
Structural Parts ◽  
The Impact

The Ti 17 (Ti-5Al-2Sn-2Zr-4Mo-4Cr) alloy is used in the first stages of engine compressors, at temperatures up to 450°C. However, its use in structural parts such as engine pylons is more prospective and raises the question of damage tolerance. As the engine pylon environment involves prolonged exposures to high temperatures, the impact of aging on mechanical properties has also to be taken in account. In this work, the consequences of a long-term aging (up to 10 000 h at 450°C) on the mechanical resistance of a Ti 17 alloy are examined at different scales, from macroscopic fatigue crack growth tests to in-situ tensile tests performed on micro samples in a SEM. The detrimental effect of aging on the mechanical properties of the Ti 17 alloy was then discussed in the light of damage mechanisms analysis and embrittlement kinetics.

scholarly journals Assessing the efficiency of a “buried wall” barrier in the establishment of near-surface long-term storage and disposal facilities for RW

2021 ◽  
Vol 14 (1) ◽  
pp. 96-105
Author(s):  
V. V. Suskin ◽  
◽  
I. V. Kapyrin ◽  
F. V. Grigorev ◽  
◽  
...  
Keyword(s):  
Near Surface ◽  
Transfer Processes ◽  
Long Term Storage ◽  
Mass Transfer Processes ◽  
High Degree ◽  
The Impact ◽  
Term Storage

The article evaluates the impact of a “buried wall” barrier on the long-term safety during the long-term storage1 or in-situ disposal of nuclear legacy facilities, in particular, industrial reservoirs, as well as during the development of near-surface disposal facilities for radioactive waste (RWDF). For assessment purposes, filtration and mass transfer processes have been numerically modelled in the GeRa code based on a case study of a reference near-surface facility. The study explores in which way the available covering screen affects the dynamics of contaminant spread. It evaluates the sensitivity of the results to the dispersion parameter commonly characterized by a high degree of uncertainty.

scholarly journals The impact of free convection on late morning ozone decreases on an Alpine foreland mountain summit

2008 ◽  
Vol 8 (2) ◽  
pp. 5437-5476
Author(s):  
J.-C. Mayer ◽  
K. Staudt ◽  
S. Gilge ◽  
F. X. Meixner ◽  
T. Foken
Keyword(s):  
Boundary Layer ◽  
Free Convection ◽  
Mixing Ratio ◽  
Tethered Balloon ◽  
Diurnal Course ◽  
Alpine Foreland ◽  
Mountain Summit ◽  
The Impact

Abstract. Exceptional patterns in the diurnal course of ozone mixing ratio at a mountain top site (998 m a.s.l.) were observed during a field experiment (September 2005). They manifested themselves as strong and sudden decreases of ozone mixing ratio levels with a subsequent return to previous levels. Considering corresponding long-term time series (2000–2005) it was found, that such events occur mainly during summer, and affect the mountain top site in about 18% of the summer days. Combining (a) surface layer measurements at mountain summit and at the foot of the mountain, (b) in-situ (tethered balloon) and remote sensing (SODAR-RASS) measurements within the atmospheric boundary layer, the origin of these events of sudden ozone decrease could be attributed to free convection, triggered by a rather frequently occurring wind speed minimum around the location of the mountain.

Substantial numerical decline in South Australian rabbit populations following the detection of rabbit haemorrhagic disease virus 2

2018 ◽  
Vol 182 (20) ◽  
pp. 574-574 ◽  
Author(s):  
Greg Mutze ◽  
Nicki De Preu ◽  
Trish Mooney ◽  
Dylan Koerner ◽  
Darren McKenzie ◽  
...  
Keyword(s):  
Disease Virus ◽  
South Australia ◽  
Rabbit Haemorrhagic Disease Virus ◽  
Environmental Benefit ◽  
Rabbit Haemorrhagic Disease ◽  
European Rabbits ◽  
Haemorrhagic Disease ◽  
The Impact ◽  
Term Monitoring

Lagovirus europaeus GI.2, also commonly known as rabbit haemorrhagic disease virus 2, was first detected at two long-term monitoring sites for European rabbits, Oryctolagus cuniculus, in South Australia, in mid-2016. Numbers of rabbits in the following 12–18 months were reduced to approximately 20 per cent of average numbers in the preceding 10 years. The impact recorded at the two South Australian sites, if widespread in Australia and persistent for several years, is likely to be of enormous economic and environmental benefit.

Lessons from long-term predator control: a case study with the red fox

2014 ◽  
Vol 41 (3) ◽  
pp. 222 ◽  
Author(s):  
Roger Kirkwood ◽  
Duncan R. Sutherland ◽  
Stuart Murphy ◽  
Peter Dann
Keyword(s):  
Population Size ◽  
Prey Species ◽  
Public Awareness ◽  
Control Period ◽  
Control Technique ◽  
Effective Control ◽  
Predator Control ◽  
Red Foxes ◽  
The Impact

Context Predator-control aims to reduce an impact on prey species, but efficacy of long-term control is rarely assessed and the reductions achieved are rarely quantified. Aims We evaluated the changing efficacy of a 58-year-long campaign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian mainland via a bridge. The campaign aimed to eliminate the impact of foxes on ground-nesting birds, particularly little penguins (Eudyptula minor). Methods We monitored the success rate of each fox-control technique employed, the level of effort invested if available, demographics of killed foxes, the numbers of penguins killed by foxes and penguin population size. Key results The campaign began as a bounty system that ran for 30 years and was ineffective. It transitioned into a coordinated, although localised, control program from 1980 to 2005 that invested considerable effort, but relied on subjective assessments of success. Early during the control period, baiting was abandoned for less effective methods that were thought to pose fewer risks, were more enjoyable and produced carcasses, a tangible result. Control was aided by a high level of public awareness, by restricted fox immigration, and by a clear, achievable and measurable target, namely, to prevent little penguin predation by foxes. Carcasses did prove valuable for research, revealing the genetic structure and shifts in fox demographics. The failure of the program was evident after scientific evaluation of fox population size and ongoing fox impacts. In 2006, the campaign evolved into an eradication attempt, adopting regular island-wide baiting, and since then, has achieved effective knock-down of foxes and negligible predation on penguins. Conclusions Effective predator control was achieved only after employing a dedicated team and implementing broad-scale baiting. Abandoning widespread baiting potentially delayed effective control for 25 years. Furthermore, both predator and prey populations should be monitored concurrently because the relationship between predator abundance and impact on prey species is not necessarily density dependent. Implications Critical to adopting the best management strategy is evaluating the efficacy of different methods independently of personal and public biases and having personnel dedicated solely to the task.

scholarly journals Night-sky imaging as a potential tool for characterization of total lumen output from small and medium-sized cities

2020 ◽  
Vol 494 (4) ◽  
pp. 5008-5017
Author(s):  
S Wallner ◽  
M Kocifaj ◽  
L Komar ◽  
H A Solano-Lamphar
Keyword(s):  
Satellite Data ◽  
Light Emitting ◽  
Large Cities ◽  
Major Interest ◽  
Night Sky ◽  
Lighting Systems ◽  
The Impact

ABSTRACT In this article, the asymptotic formula developed in past work and applied to predict skyglow due to distant sources was evolved, with the objective of characterizing small and medium-sized cities in the observer's surroundings. To enable this, a combination of theoretical computations and in situ measurements is needed, aiming to distinguish between dominant and smaller light-emitting sources, with the latter usually being camouflaged when measuring the night sky. Furthermore, for numerical modelling of skyglow, few of the most important parameters, specifically the amount of total lumens installed and radiated to the upward hemisphere, can be derived. Astronomical observatories, in particular, can profit from this concept, since they are usually situated far away from large cities but can still be surrounded by smaller villages and towns. We present a detailed description of how theoretical computations are combined with all-sky photometry in order to obtain the properties mentioned. Results are compared with satellite data, showing that, regarding approximations undertaken for processing, they are comparable, underlining the functionality of our approach. The idea of including in situ observations enables us to quantify the impact of small and medium-sized cities globally and independent of location, as long as measurements were conducted outside light domes. In addition, the presented work may be of major interest to the light-pollution community if conducting long-term observations of cities, since the quality of commonly used satellite data is going to decrease in the future, due to blindness in short wavelengths and upcoming conversions of public lighting systems to blue-enlightened LEDs.

The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. I. Exploring potential impact using diet analysis

1999 ◽  
Vol 26 (5) ◽  
pp. 621 ◽  
Author(s):  
Jeff Short ◽  
Michael C. Calver ◽  
Danielle A. Risbey
Keyword(s):  
Western Australia ◽  
Prey Species ◽  
Food Type ◽  
Gut Contents ◽  
Frequency Of Occurrence ◽  
Feral Cats ◽  
Important Prey ◽  
Introduced Predators ◽  
Small Vertebrate ◽  
The Impact

The diets of cats (Felis catus) and foxes (Vulpes vulpes) killed during predator control at a semi-arid site in Western Australia were studied to see which prey species may be affected by predation from these introduced predators. The number of items, biomass and frequency of occurrence of each food type in the gut contents from 109 feral cats, 62 semi-feral cats and 47 foxes were used to calculate an Index of Relative Importance for each food category for each predator. Mammals were the most important prey group for all three predators, with rabbit being the most highly ranked prey species. The diets of feral and semi-feral cats were similar in dietary diversity but differed in the frequency of occurrence of some food categories. Native rodents, birds and reptiles occurred more frequently and were ranked higher in the diet of feral cats, and food scraps occurred more frequently in the diet of semi-feral cats. The diet of foxes was less diverse than that of either group of cats. Invertebrates and sheep carrion were more important prey categories for foxes than for cats. In the summer–autumn period, foxes ate more sheep carrion and invertebrates than they did in winter–spring. The diet of feral cats was more diverse in summer–autumn, including a greater range of invertebrates and more rodents, birds and reptiles than in the winter–spring period. We predict that cats are more likely to have an impact on small vertebrates at this site and that the control of cats could lead to recoveries in the populations of native rodents, birds and reptiles. By contrast, the control of foxes alone may lead to a rise in cat numbers and a consequent detrimental impact on small vertebrate populations.

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