scholarly journals Interactions between a Top Order Predator and Exotic Mesopredators in the Australian Rangelands

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Katherine E. Moseby ◽  
Heather Neilly ◽  
John L. Read ◽  
Helen A. Crisp
Keyword(s):  
Intraguild Predation ◽  
Prey Species ◽  
Red Fox ◽  
Interference Competition ◽  
South Australia ◽  
Mortality Rates ◽  
Net Benefit ◽  
Male And Female ◽  
Dominant Mechanism ◽  
Feral Cats

An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.

Evidence of significantly higher island feral cat abundance compared with the adjacent mainland

2019 ◽  
Vol 46 (5) ◽  
pp. 378 ◽  
Author(s):  
Patrick L. Taggart ◽  
Bronwyn A. Fancourt ◽  
Andrew J. Bengsen ◽  
David E. Peacock ◽  
Patrick Hodgens ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Spatial Model ◽  
Native Species ◽  
Prey Species ◽  
South Australia ◽  
Camera Trap ◽  
Feral Cat ◽  
Feral Cats ◽  
Continental Scale ◽  
Scale Models

Context Feral cats (Felis catus) impact the health and welfare of wildlife, livestock and humans worldwide. They are particularly damaging where they have been introduced into island countries such as Australia and New Zealand, where native prey species evolved without feline predators. Kangaroo Island, in South Australia, is Australia’s third largest island and supports several threatened and endemic species. Cat densities on Kangaroo Island are thought to be greater than those on the adjacent South Australian mainland, based on one cat density estimate on the island that is higher than most estimates from the mainland. The prevalence of cat-borne disease in cats and sheep is also higher on Kangaroo Island than the mainland, suggesting higher cat densities. A recent continental-scale spatial model of cat density predicted that cat density on Kangaroo Island should be about double that of the adjacent mainland. However, although cats are believed to have severe impacts on some native species on the island, other species that are generally considered vulnerable to cat predation have relatively secure populations on the island compared with the mainland. Aims The present study aimed to compare feral cat abundance between Kangaroo Island and the adjacent South Australian mainland using simultaneous standardised methods. Based on previous findings, we predicted that the relative abundance of feral cats on Kangaroo Island would be approximately double that on the South Australian mainland. Methods Standardised camera trap surveys were used to simultaneously estimate the relative abundance of feral cats on Kangaroo Island and the adjacent South Australian mainland. Survey data were analysed using the Royle–Nichols abundance-induced heterogeneity model to estimate feral cat relative abundance at each site. Key results Cat abundance on the island was estimated to be over 10 times greater than that on the adjacent mainland. Conclusions Consistent with predictions, cat abundance on the island was greater than on the adjacent mainland. However, the magnitude of this difference was much greater than expected. Implications The findings show that the actual densities of cats at local sites can vary substantially from predictions generated by continental-scale models. The study also demonstrates the value of estimating abundance or density simultaneously across sites using standardised methods.

The diet of the feral cat (Felis catus), red fox (Vulpes vulpes) and dog (Canis familiaris) over a three-year period at Witchelina Reserve, in arid South Australia

2018 ◽  
Vol 40 (2) ◽  
pp. 204 ◽  
Author(s):  
John C. Z. Woinarski ◽  
Sally L. South ◽  
Paul Drummond ◽  
Gregory R. Johnston ◽  
Alex Nankivell
Keyword(s):  
Vulpes Vulpes ◽  
Red Fox ◽  
Canis Familiaris ◽  
South Australia ◽  
Felis Catus ◽  
Feral Cats ◽  
Significant Seasonal Variation ◽  
Introduced Predators ◽  
Pogona Vitticeps ◽  
First Time

Introduced predators have had, and continue to have, severe impacts on Australian biodiversity. At a recently established conservation reserve, Witchelina, in arid South Australia, we assessed the diet of feral cats (Felis catus) (404 samples), red fox (Vulpes vulpes) (51 samples) and dog (Canis familiaris) (11 samples) over a 3-year period. There was marked overlap (98.5%) in dietary composition between cats and foxes. Rabbits (Oryctolagus cuniculus) comprised a major dietary item for all three predators. Invertebrates contributed the largest number of prey items for foxes and cats, but mammals comprised the bulk, by weight, for all three predators. Birds and reptiles had a higher frequency of occurrence in the diet of cats than of foxes or dogs. The size of mammal prey taken was least for cats and greatest for dogs. The diets of cats and foxes showed significant seasonal variation, with reptiles and invertebrates being least common in the diet in winter. The threatened thick-billed grasswren (Amytornis modestus) was found for the first time in the diet of feral cats. Bearded dragons (Pogona vitticeps) occurred in about one-third of cat and fox samples. This study contributes further to the evidence of biodiversity impacts of introduced predators, and the need for their strategic management.

Management of invasive mesopredators in the Flinders Ranges, South Australia: effectiveness and implications

2020 ◽  
Vol 47 (8) ◽  
pp. 720
Author(s):  
Alyson M. Stobo-Wilson ◽  
Robert Brandle ◽  
Christopher N. Johnson ◽  
Menna E. Jones
Keyword(s):  
Prey Species ◽  
South Australia ◽  
Short Time Period ◽  
Short Term ◽  
Feral Cat ◽  
Feral Cats ◽  
Flinders Ranges ◽  
Time Period ◽  
Short Time ◽  
The Impact

Abstract ContextSignificant resources have been devoted to the control of introduced mesopredators in Australia. However, the control or removal of one pest species, such as, for example, the red fox (Vulpes vulpes), may inadvertently benefit other invasive species, namely feral cats (Felis catus) and rabbits (Oryctolagus cuniculus), potentially jeopardising native-species recovery. AimsTo (1) investigate the impact of a large-scale, long-term fox-baiting program on the abundance of foxes, feral cats and introduced and native prey species in the Flinders Ranges, South Australia, and (2) determine the effectiveness of a short time period of cat removal in immediately reducing feral cat abundance where foxes are absent. MethodsWe conducted an initial camera-trap survey in fox-baited and unbaited sites in the Flinders Ranges, to quantify the impact of fox baiting on the relative abundance of foxes, feral cats and their prey. We then conducted a secondary survey in sites where foxes were absent, following an intensive, but short, time period of cat removal, in which 40 cats were shot and killed. Key resultsNo foxes were detected within baited sites, but were frequently detected in unbaited sites. We found a corresponding and significant increase in several native prey species in fox-baited sites where foxes were absent. Feral cats and rabbits were also more frequently detected within baited sites, but fox baiting did not singularly predict the abundance of either species. Rather, feral cats were less abundant in open habitat where foxes were present (unbaited), and rabbits were more abundant within one predominantly open-habitat site, where foxes were absent (fox-baited). We found no effect of short-term cat removal in reducing the local abundance of feral cats. In both camera-trap surveys, feral cat detections were positively associated with rabbits. ConclusionsLong-term fox baiting was effective in fox removal and was associated with a greater abundance of native and introduced prey species in the Flinders Ranges. To continue to recover and conserve regional biodiversity, effective cat control is required. ImplicationsOur study showed fox removal has likely resulted in the local release of rabbits and an associated increase in cats. Because feral cat abundance seemingly fluctuated with rabbits, we suggest rabbit control may provide an alternative and more effective means to reduce local feral cat populations than short-term removal programs.

Population dynamics, diet and aspects of the biology of feral cats and foxes in arid South Australia

2001 ◽  
Vol 28 (2) ◽  
pp. 195 ◽  
Author(s):  
John Read ◽  
Zoë Bowen
Keyword(s):  
Population Dynamics ◽  
South Australia ◽  
House Mice ◽  
Male And Female ◽  
Feral Cats ◽  
Wide Range ◽  
Bird Breeding

Average cat and fox densities at Roxby Downs, in northern South Australia, of 0.8 and 0.6 km–2 respectively, determined through spotlight counts over a 10-year period, probably considerably underestimate true densities. Peak rabbit populations coincided with high fox numbers, which probably suppressed cat densities. Cat abundance peaked when fox numbers were low but rabbit numbers were relatively high. When abundant, rabbits were the principal prey of both cats and foxes. Declines in rabbits numbers coincided with dramatic declines in fox numbers. By contrast, declines in cat populations were less marked, presumably because they could more effectively switch to hunting a wide range of native vertebrates. Sand-dwelling lizards, house mice and common small passerines were the most abundant non-rabbit, vertebrate prey taken by cats. We estimate that annual cat predation accounted for approximately 700 reptiles, 150 birds and 50 native mammals per square kilometre, whereas foxes consumed on average 290 reptiles per square kilometre and few native mammals and birds in the Roxby Downs region each year. Male cats and foxes were heavier than females. Feral cats typically weighed less than 4.0 kg, and cats weighing less than 2.5 kg typically preyed on more native vertebrates than did larger cats. Male and female cats were both typically tabby coloured, but a higher proportion of males were ginger in colour. Peak cat breeding coincided with rabbit and bird breeding and increased reptile activity during spring.

scholarly journals Influence of competition and intraguild predation between two candidate biocontrol parasitoids on their potential impact against Harrisia cactus mealybug, Hypogeococcus sp. (Hemiptera: Pseudococcidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María B. Aguirre ◽  
Octavio A. Bruzzone ◽  
Serguei V. Triapitsyn ◽  
Hilda Diaz-Soltero ◽  
Stephen D. Hight ◽  
...  
Keyword(s):  
Intraguild Predation ◽  
Interference Competition ◽  
Biocontrol Agents ◽  
Parasitoid Species ◽  
Temporal Window ◽  
Response Models ◽  
Potential Impact ◽  
Functional Response Models ◽  
Fully Bayesian ◽  
Release Strategy

AbstractWhen two or more parasitoid species, particularly candidates for biocontrol, share the same target in the same temporal window, a complex of behaviors can occur among them. We studied the type of interactions (competition and intraguild predation) that existed between the nymphal parasitoids Anagyrus cachamai and A. lapachosus (Hymenoptera: Encyrtidae), two candidate neoclassical biocontrol agents against the Puerto Rican cactus pest mealybug, Hypogeococcus sp. (Hemiptera: Pseudococcidae). The surrogate native congener host in Argentina, the cactus mealybug Hypogeococcus sp., was studied to predict which species should be released; in the case that both should be released, in which order, and their potential impact on host suppression. In the laboratory we conducted experiments where different densities of the host mealybug were exposed to naive females of A. cachamai and A. lapachosus sequentially in both directions. Experiments were analyzed by combining a series of competitive behavioral and functional response models. A fully Bayesian approach was used to select the best explaining models and calculate their parameters. Intraguild predation existed between A. cachamai, the species that had the greatest ability to exploit the resource, and A. lapachosus, the strongest species in the interference competition. The role that intraguild predation played in suppression of Hypogeococcus sp. indicated that a multiple release strategy for the two biocontrol agents would produce better control than a single release; as for the release order, A. lapachosus should be released first.

Sharing meals: Predation on Australian mammals by the introduced European red fox compounds and complements predation by feral cats

2021 ◽  
Vol 261 ◽  
pp. 109284
Author(s):  
Alyson M. Stobo-Wilson ◽  
Brett P. Murphy ◽  
Heather M. Crawford ◽  
Stuart J. Dawson ◽  
Chris R. Dickman ◽  
...  
Keyword(s):  
Red Fox ◽  
Feral Cats

Effect of selenium supplementation on survival, liveweight and wool weight of young sheep on Kangaroo Island, South Australia

1979 ◽  
Vol 19 (101) ◽  
pp. 689 ◽  
Author(s):  
SK Walker ◽  
GP Hall ◽  
DH Smith ◽  
RW Ponzoni ◽  
GJ Judson
Keyword(s):  
Total Dose ◽  
Whole Blood ◽  
Sodium Selenite ◽  
South Australia ◽  
Selenium Concentration ◽  
Mortality Rates ◽  
Selenium Supplementation ◽  
First Year ◽  
Weaning Weight ◽  
Fleece Weight

The responses in liveweight, wool weight and survival, to selenium supplementation, were studied in young sheep from weaning to yearling age. The experiment was conducted over three years. In the first year, one sodium selenite supplementation rate was used (total dose 46.5 mg). During the following two years two supplementation rates were administered (total doses 46.5 mg and 93 mg). Mean concentrations of selenium in whole blood in unsupplemented sheep varied from 0.19-0.56 pmol l-l and from 0.20-0.44 pmol l-1 in the two years in which concentrations were measured. Supplementation, which commenced at lamb marking, increased the selenium concentration in sheep at weaning and thereafter. Selenium supplementation improved the break-of-season weight (P < 0.01) and yearling weight (P < 0.01 ) but not weaning weight (0.05 < P < 0.1 ). Hogget fleece weight was improved (P < 0.01 ) and mortality reduced (P < 0.01) by selenium supplementation. There was a treatment x year interaction in mortality rates (P < 0.01 ). There were no significant differences between the two supplementation rates

scholarly journals Making inference from wildlife collision data: inferring predator absence from prey strikes

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3014 ◽  
Author(s):  
Peter Caley ◽  
Geoffrey R. Hosack ◽  
Simon C. Barry
Keyword(s):  
Prey Species ◽  
Red Fox ◽  
Prey Availability ◽  
Numerical Response ◽  
Practical Application ◽  
Ecological Inference ◽  
Predator Species ◽  
New Approach ◽  
Predictive Probability ◽  
Irreducible Uncertainty

Wildlife collision data are ubiquitous, though challenging for making ecological inference due to typically irreducible uncertainty relating to the sampling process. We illustrate a new approach that is useful for generating inference from predator data arising from wildlife collisions. By simply conditioning on a second prey species sampled via the same collision process, and by using a biologically realistic numerical response functions, we can produce a coherent numerical response relationship between predator and prey. This relationship can then be used to make inference on the population size of the predator species, including the probability of extinction. The statistical conditioning enables us to account for unmeasured variation in factors influencing the runway strike incidence for individual airports and to enable valid comparisons. A practical application of the approach for testing hypotheses about the distribution and abundance of a predator species is illustrated using the hypothesized red fox incursion into Tasmania, Australia. We estimate that conditional on the numerical response between fox and lagomorph runway strikes on mainland Australia, the predictive probability of observing no runway strikes of foxes in Tasmania after observing 15 lagomorph strikes is 0.001. We conclude there is enough evidence to safely reject the null hypothesis that there is a widespread red fox population in Tasmania at a population density consistent with prey availability. The method is novel and has potential wider application.

scholarly journals On Dynamics of Gender-Specific Mortality Among the Population of the Republic of Belarus in the Second Half of the XX – the Beginning of the XXI Centuries

2017 ◽  
Vol 24 (3) ◽  
Author(s):  
A Romanova ◽  
O Krasko
Keyword(s):  
Mortality Rate ◽  
Environmental Changes ◽  
Research Work ◽  
Mortality Rates ◽  
Female Mortality ◽  
Female Population ◽  
Male And Female ◽  
Crude Mortality ◽  
The Republic ◽  
Population Mortality

Aim of the study: to evaluate the dynamics and to make a comparative analysis of male and female mortality among the population of Belarus Republic during 1959 – 2015.Materials and methods. The data on natural population movement in the Republic of Belarus during 1959 – 2015 have been analyzed in the research work. Crude and standardized mortality rates have been calculated using the direct standardization according to the world standard (Standard “World”), approved by WHO. JoinPoint software was used to investigate time trends as well as office suite MSEXCEL 2010.Results of the study. The minimum values of male and female crude and standardized mortality rates were established in 1964. Throughout the study period, the male population mortality rate grew 1.8-fold (based on crude rates – 2.4-fold), the female population mortality rate – 1.6-fold (based on crude rates – 2.2-fold). During 1985 – 2005, the differences in crude mortality rates among men and women grew 1.2-fold, and during 1962 – 2011, the differences in standardized rates increased 1.8-fold. Since 2003, the mortality rate among men and since 1999, the death rate among women has declined with an annual decrease rate to be more than twice as high as compared to an annual mortality increase registered during its growth.Conclusion. Since the 1960s, the changes in population age structure of the male and female population affected the crude mortality rates. The male and female mortality growth is due to an increased unfavorable impact of combined environmental factors. The adaptive capacity of women to sustain environmental changes contributed to their later entry into the period of mortality growth, as compared to men. The mortality rate reduction in men since 2003 and the excess of a decrease over an increase rate is associated with a set of state measures aimed at protecting and strengthening the public health in the republic.

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