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Save Australia’s Ecological Research
Last week, in collaboration with 68 scientists, I was co-author on a letter in Science titled “Save Australia’s Ecological Research”
The letter calls on the Federal Government to reverse its decision to cease funding Australia’s Long Term Ecological Research Network (LTERN). The network comprises more than 1100 long-term field plots across Australia, including those in the Simpson Desert (pictured above) where I have conducted research in collaboration with the Desert Ecology Research Group at The University of Sydney.
The letter has been featured in a news piece by John Pickrell in Science titled “Australia to ax support for long-term ecology sites“, as well as in a news piece by Nicky Phillips in Nature titled “Ecologists protest Australia’s plans to cut funding for environment-monitoring network”
The existing program receives $900,000 of support from the Federal Government’s Terrestrial Ecosystem Research Network (TERN). This support is being slashed at a time when even the USA is increasing funding for its own network by US$5.6M annually.
Hopefully a last ditch bid to the Federal Government by those who administer and lead LTERN will result in a reversal of this decision, and even better, an expansion of the program.
Fifth Book Review
Richard (Dick) MacMillen (Professor Emeritus of Ecology and Evolutionary Biology, University of California, Irvine) recently reviewed our book “The Red Kangaroo in Central Australia; an early account by A.E. Newsome”.
The review was published in the May issue of Journal of Mammalogy.
A copy of the review is provided below:
“This gem of a book about Australia’s iconic symbol, the red kangaroo (Osphranter rufus; formerly Megaleia rufus, Macropus rufus; Jackson and Groves 2015), will serve as an inspiration to younger field-oriented mammalian ecologists and equally admired by more seasoned ones. It is a newly polished chronicle of an unfinished manuscript of pioneering field research conducted by Alan Newsome in Central Australia between 1957 and 1962, a region that then was still in a frontier state. The research took place when Alan was fresh out of the University of Queensland with just an undergraduate science degree. Alan had contracted with the Animal Industry Branch of the Northern Territory Government to learn all he could about the life history of the red kangaroo and its interactions with cattle in the arid interior of the Northern Territory, while other ecologists were conducting comparable studies in Western Australia, South Australia, and New South Wales.
It is unclear when Alan began drafting this manuscript, but the last dated correspondence with a potential publisher, Collins Publishing, was 1975. For reasons unknown, the manuscript was placed in storage at his home in Canberra, and was not refound until 2010, following Alan’s untimely death from Alzheimer’s disease in 2007. The manuscript and various notes and colored slides were discovered amongst his belongings by his wife Jane Thompson, and his son Thomas Newsome; Thomas is a promising young ecologist in his own right, with extensive field experience in the Northern Territory’s arid heart, and therefore all the more suited to see the manuscript through to publication. In so doing, Thomas sought faithfully to retain his father’s writing style, and transcribed the 6 manuscript chapters pretty much verbatim, even though they varied in their completeness from near final drafts to hand-scrawled notations.
From this has emerged a narrative description of a monumental 6-year ecological study in Central Australia, under the harshest of conditions of drought – summer daytime temperatures sometimes reaching 50 C – undertaken by a young man who, at its inception, was age 22. Provided with a four-wheel drive vehicle, access to a light airplane and pilot, a skilled rifle marksman, and indigenous aboriginal aids and informants, it still required a leader with exceptional organizational skills to design and execute the scale of study the goals demanded; that leader was the young Alan Newsome, who more than met those goals. In so doing, Alan established a study area in a vast region on the Burt Plain to the north of the MacDonnell Ranges that lie to the north and west of Alice Springs, N.T. The study area comprised 4 recognizable land-systems with discernible but overlapping plant components that lent themselves both to aerial surveys for kangaroo distribution and abundance, and ground-based collections for necropsy analysis of reproductive and physical condition; these studies spanned climatic events of prolonged drought finally broken by abundant rainfall over a region where, concomitantly, cattle grazed.
Repeated flights over fixed aerial transects during the study period revealed that these grass-dependent marsupials prefer to remain in the vicinity of mulga (Acacia aneura) woodlands, where their primary food, green grass, abounds in periods of normal rain; but, as drought ensues and these grasses dry up, there is a mass movement toward and into the open plains, where there are widely scattered seeps and springs which also attract cattle. There the cattle graze on the drying grass, which stimulates vegetative regrowth providing the kangaroos with a continuing supply of green food until the next rain cycle; then they will move back into the woodlands. Thus kangaroos, if anything, benefit from the presence of cattle during drought.
Between 1958 and 1963 a system of random ground sampling of red kangaroos was established at night along fixed transects in woodlands and open plains during and following drought, by spotlighting randomly selected animals from a vehicle; these were then shot to assess reproductive condition and physical state. About 2000 kangaroos were collected from which stomach samples and reproductive tracts were preserved for analysis. Stomach analyses confirmed that green grasses comprised the kangaroos’ diets, even during drought. Reproductively, female red kangaroos nearly always had a suckling joey either in the pouch or at foot, as well as an embryonic blastocyst in an arrested state of development (i.e. diapause) in the uterus; this latter condition was described earlier in detail in a small wallaby (the quakka) by Sharman (1954), and likely is characteristic of macropods in general. Continued development of the blastocyst occurs only following cessation of nursing of the preceding joey, either through weaning or death. Upon birth of a near-embryonic fetus, the mother kangaroo undergoes ovulation and postparturient mating, assuming a fertile male is present. Thus, even during severe drought resulting in a joey’s death, another replacement young is soon present to increase the probability of population survival. In a sense then, this macropod capacity of arrested development is a preadaptation for surviving drought, even though other circumstances may have stimulated its original evolution. In the males spermatogenesis resulting in fertility seemed to be unaffected by drought, except during the hottest, prolonged summer periods when some kangaroos in the open plains were without shelter, and unable to regulate testicular temperature compatible with sperm production; but even during these summer droughts at least some fertile males were always present, ensuring successful reproduction.
Alan also draws attention to the advantages during drought of the female kangaroo’s gestational characteristics compared to those of a cow, when both are competing for the same diminishing supply of grass. The kangaroo has a gestation period of only 5 weeks, yielding a tiny newborn weighing less than 1 g, and with minimal maternal investment other than that spent in milk production. In contrast, a pregnant cow has a gestation period of 9 months that yields a very large calf whose development has drawn heavily upon maternal bodily resources. If during drought, this may leave the cow in a severely depleted state, resulting in her death and then that of the milk-deprived calf. Thus this marsupial reproductive characteristic serendipitously favors success of the red kangaroo during drought.
Thomas Newsome has masterfully polished his father’s incomplete manuscript by adding appropriate photographs from Alan’s slide collection, maps scaled to geographic descriptions, and quantitative tables that document results and conclusions; these latter were derived largely from a series of articles Alan published between 1964 and 1973 (e.g., Newsome, 1971). Together, the authors provide an informative and provocative read about a truly remarkable mammal.
The final chapter (Ch. 7) is a reproduction of an article Alan published in the anthropological journal Mankind in 1980 that demonstrates the congruence of Aboriginal oral history (“mythology”) with Alan’s own intuitive and observational ecological conclusions concerning movement during drought of red kangaroos. During the course of his studies Alan was frequently in contact with Aboriginal people from the Aranda totemic group, whose mythological ancestor is Ara, the red kangaroo. Not only did Alan receive physical aid from some of these people, but they must also have shared bits of their ancestral mythology. In addition, Alan was greatly influenced by the writings of Ted Strehlow, a Central Australian anthropologist born and raised on an Aboriginal mission near Alan’s study area, and who spoke the Aranda dialect fluently. In particular, he was impacted by Strehlow’s book, Songs of Central Australia (1971), that included Aranda mythology about travels of the red kangaroo during drought between watering and feeding sites. According to Aboriginal legend, during non-drought conditions feeding and watering points were fairly readily available at sites along the northern base of the MacDonnell Ranges, and further out amongst the mulga woodlands; the kangaroos could readily travel overland between them. As drought ensued these watering points gradually dried up, forcing the kangaroos to travel progressively further out onto the open plains to find food and water at sites far distant from each other. This led to the mythological belief that the travel between such distant sites must have been through underground passages, enabling the kangaroos to avoid perhaps lethal surface conditions. Alan concluded that the mythological descriptions of many of these watering points matched where he had observed kangaroos feeding and drinking during and after drought, and that at least this part of Aboriginal mythology must be based upon a keen sense of ecological perception, enhancing Aboriginal access to their preferred protein source during demanding environmental circumstances.
In 1989, while on a research leave in Australia, my wife, son, and I had the great pleasure and privilege of accompanying Alan from Alice Springs around to the north slopes of the MacDonnell Ranges to see one of these totemic sites he had identified, and as described in Strehlow (1971); Alan felt comfortable in taking us there as all of the Aboriginal elders who had held the tribal secrets had passed on. It was a humbling experience to witness this congruity between Aboriginal mythology and ecological reality, particularly when, upon departing the site, a large red kangaroo crossed the track ahead of us. And, as Thomas Newsome so aptly states in his Preface to the book: “It remains a groundbreaking piece of work, a pioneering example of why ecologists and land managers alike should listen to, and learn from, Indigenous knowledge”.
I first met Alan at Adelaide University in 1966 during my initial sabbatical leave in Australia, while I was on a seminar junket from my host institution, Monash University near Melbourne. Alan, who was my junior by 3 years, immediately struck me as a warm, congenial and knowledgeable ecologist with whom I could readily become a close friend and colleague. Since then our paths had crossed many times, both during my numerous research leaves in Australia, and when he was our guest as Regents Professor of Ecology and Evolutionary Biology in my department at U.C. Irvine. During the latter period we interacted intensively both at professional and family levels. Although we never had the opportunity to collaborate directly in research, my work in Central Australia certainly was influenced by his many outstanding contributions. I have felt from the beginning, as I do today, that, in addition to a keen intellect, it was Alan’s ability to communicate with virtually anyone at his or her own level, whether it be a cattle station manager, an Aboriginal informant, a research colleague, a student, or a friend, that made him such a successful individual. These communication skills together with his high capacity for organization enabled him to complete successfully, even as a novice field ecologist, an enormous amount of important work. This book, then, should be read and appreciated as such and as a tribute to Alan Newsome, and it is appropriately dedicated to him by his son, Thomas. Alan, we miss you, Mate! DICK MACMILLEN, Professor Emeritus of Ecology and Evolutionary Biology, University of California, Irvine; 705 Foss Road, Talent, OR 97540, USA;
JACKSON, S, and C. GROVES. 2015. Taxonomy of Australian mammals. CSIRO Publishing, Collingwood, Australia.
NEWSOME, A.E. 1971. The ecology of red kangaroos. Australian Zoologist 16: 32-50.
NEWSOME, A.E. 1980. The eco-mythology of the Red Kangaroo in Central Australia. Mankind 12: 327-333.
SHARMAN, G.B. 1954. Reproduction in marsupials. Nature 173: 302-303;
STREHLOW, T.G.H. 1971. Songs of Central Australia. Angus & Robertson. Sydney, Australia.”
Thanks Dick for the kind review!
New paper: top predators constrain mesopredator distributions
In a paper published last week in Nature Communications we explored relationships between top predators and lower order predators (mesopredators) across three separate continents. We found that top predators can suppress the abundances of mesopredators, but only when top predators occur at high densities over large areas. The results have important implications for understanding the ecological role of top predators, like dingoes and wolves, and for the conservation of ecosystems more broadly.
The results have been summarised in The Conversation.
See below for links to some of the media generated and for a copy of the abstract.
Reintroducing dingoes can help manage feral foxes and cats, study suggests (SMH)
Dingoes could be used to control fox numbers and prevent ecological decline (ABC)
Dingoes need more space to fight off pests, study finds (Australian Geographic)
Dingoes to the rescue? (Deakin University)
Wolves need space to roam to control expanding coyote population (University of Washington)
Study: to mitigate problem predators, give wolves more space, tolerance (KUOW)
Top predators can suppress mesopredators by killing them, competing for resources and instilling fear, but it is unclear how suppression of mesopredators varies with the distribution and abundance of top predators at large spatial scales and among different ecological contexts. We suggest that suppression of mesopredators will be strongest where top predators occur at high densities over large areas. These conditions are more likely to occur in the core than on the margins of top predator ranges. We propose the Enemy Constraint Hypothesis, which predicts weakened top-down effects on mesopredators towards the edge of top predators’ ranges. Using bounty data from North America, Europe and Australia we show that the effects of top predators on mesopredators increase from the margin towards the core of their ranges, as predicted. Continuing global contraction of top predator ranges could promote further release of mesopredator populations, altering ecosystem structure and contributing to biodiversity loss.
Global Impacts of Domestic Dogs
In a recent paper we explored the global impacts of domestic dogs on wildlife.
For a summary see our opinion piece published in The Conversation.
Below is a copy of the abstract and you can view the paper HERE.
Domestic dogs (Canis familiaris) have a near-global distribution. They range from being feral and free-ranging to owned and completely dependent on humans. All types of domestic dogs can interact with wildlife and have severe negative impacts on biodiversity. Here, we use IUCN Red List data to quantify the number of threatened species negatively impacted by dogs, assess the prevalence of different types of dog impact, and identify regional hotspots containing high numbers of impacted species. Using this information, we highlight key research and management gaps and priorities. Domestic dogs have contributed to 11 vertebrate extinctions and are a known or potential threat to at least 188 threatened species worldwide. These estimates are greater than those reported by previous assessments, but are probably conservative due to biases in the species, regions and types of impacts studied and/or reported. Predation is the most frequently reported impact, followed by disturbance, disease transmission, competition, and hybridisation. Regions with the most species impacted are: South-east Asia, Central America and the Caribbean, South America, Asia (excluding SE), Micro/Mela/Polynesia, and Australia. We propose that the impacts of domestic dogs can be better understood and managed through: taxonomic and spatial prioritisation of research and management; examining potential synergisms between dogs and other threatening processes; strategic engagement with animal welfare and human health campaigns; community engagement and education; and mitigating anthropogenic effects such as resource subsidies. Such actions are essential for threatened species persistence, especially given that human and dog populations are expected to increase both numerically and geographically in the coming decades.
The Redomestication of Wolves
Our paper “Making a new dog?” was published today in the journal BioScience, it is free to view and has been selected as Editor’s choice for the forthcoming April issue.
Below is a copy of the press release prepared by BioScience.
It has generated some news stories already, including a feature piece in Science titled “Are some wolves being ‘redomesticated’ into dogs?”
Press Release by BioScience:
On landscapes around the world, environmental change is bringing people and large carnivores together—but the union is not without its problems. Human–wildlife conflict is on the rise as development continues unabated and apex predators begin to reoccupy their former ranges. Further complicating matters, many of these species are now reliant on anthropogenic, or human foods, including livestock, livestock and other ungulate carcasses, and garbage.
Writing in BioScience, Thomas Newsome, of Deakin University and the University of Sydney, and his colleagues use gray wolves and other large predators as case studies to explore the effects of anthropogenic foods. They find numerous instances of species’ changing their social structures, movements, and behavior to acquire human-provisioned resources. For instance, in central Iran, gray wolves’ diets consist almost entirely of farmed chickens, domestic goats, and garbage.
Other instances of these phenomena abound. In a similar case in Australia, dingoes gained access to anthropogenic foods from a waste facility. The result, according to the authors, was “decreased home-range areas and movements, larger group sizes, and altered dietary preferences to the extent that they filled a similar dietary niche to domestic dogs.” Moreover, wrote the authors, “the population of subsidized dingoes was a genetically distinct cluster,” which may portend future speciation events. Hybridization among similar predator species may also contribute to evolutionary divergence: “Anthropogenic resources in human-modified environments could increase the probability of non-aggressive contact” between species. According to the authors, “If extant wolves continue to increase their reliance on anthropogenic foods, we should expect to observe evidence of dietary niche differentiation and, over time, the development of genetic structure that could signal incipient speciation.”
Wolves’ use of anthropogenic food could have serious implications for wider conservation efforts, as well. In particular, Newsome and his colleagues raise concerns about whether wolf reintroduction and recolonisation programs will meet ecosystem-restoration goals in human-modified systems. Managers will need to consider “how broadly insights into the role played by wolves gleaned from protected areas such as Yellowstone can be applied in areas that have been greatly modified by humans,” say the authors.
Newsome and his colleagues call for further research—in particular, “studies showing the niche characteristics and population structure of wolves in areas where human influence is pervasive and heavy reliance on human foods has been documented.” Through such studies, they argue that “we might be able to ask whether heavy reliance of anthropogenic subsidies can act as a driver of evolutionary divergence and, potentially, provide the makings of a new dog.”
Fourth Book Review
Rob Wallis from the Office of the Deputy Vice-Chancellor (Research & Innovation), the Federation University Australia, recently reviewed our book “The Red Kangaroo in Central Australia; an early account by A.E. Newsome”.
The review was published in the February 2017 issue of The Victorian Naturalist.
A copy of the review is provided below:
“Alan Newsome was one of Australia’s great naturalists and also a leading scientist whose early work focused on the biology of the Red Kangaroo Osphranter rufus. His work on the species began in 1957 and, unbeknown to his family, he had been preparing a book on his research which the publisher (Collins) was expecting to be completed in 1975. However, like so many things in people’s busy lives, it got put aside; why it was never completed remains a mystery. In 2010 his son Thomas discovered the manuscript in a box of materials his father had left behind in his son’s Canberra garage and, after a thorough read of it, Thomas decided to edit it for publication. I suspect Alan intended this book to be primarily an account of the biology of the Red Kangaroo, elucidated by his field work. If readers treat it as such, they will be somewhat disappointed as there have been many more accounts of kangaroo biology published recently that are much more up-to-date and complete. Indeed, this journal has published reviews of such books.
What makes this book a fascinating read, however, is the description of how this pioneer of ecological research went about his work. As the preface notes:
It is rare for an ecologist to write reflectively and personally about the experience of discovery, especially during the early stages of a career … I suspect it is also because few early career scientists have a journey that results in the kind of pioneering discoveries that Alan’s did (p. xx).
Alan Newsome’s research dispelled many myths and incorrect claims about Red Kangaroos. His blend of acute observational skills of a naturalist combined with rigorous scientific examination helped answer these questions:
…why were red kangaroos so abundant on open plains and creeks during droughts, and more so on some than others? Where did they disappear to after rain? Why did they sometimes congregate to form large mobs? What did they eat and did they compete severely or at all with cattle and sheep? How did kangaroos foul pastures as claimed? How could 5 to 10 shooters work one 500 km2 plain 50 km north of Alice Springs night after night in the 1950s without making an impression on numbers? Their breeding would seem to be prodigious for such to happen. So what were the reproductive processes, and what ensured reproductive success?…..Why did kangaroos appear to be more numerous on cattle country than land never stocked? Was it due to stock waters man has made? If so, why were kangaroos so rarely seen at water? Had kangaroos always been so numerous? (pp. 9–10).
For so many questions to be answered in such a slim book is remarkable, especially when they are explained so clearly and logically!
Explorers’ accounts of Central Australia suggest the Red Kangaroo was quite rare before European exploitation of the environment. Yet Newsome observed huge mobs—one of about 1500 animals south of Alice Springs. These massive changes in numbers reflect significant environmental change—change that Newsome also noted had deleterious effects on small to medium sized fauna, which was facing extirpation. His observations and suggested explanations make interesting reading.
Thomas Newsome notes his father rated his paper ‘The Eco-Mythology of the Red Kangaroo in Central Australia’ published in 1980 as his favourite, yet the manuscript proved very difficult to get accepted and remains infrequently cited. Fortunately it is reproduced in full in the book. I found it fascinating in demonstrating Indigenous myths that turned out to be based on sound ecological knowledge. Newsome’s work was prescient—today we should recognise the value of Indigenous knowledge as a sound basis for ecological research and that proper management of our natural assets are best achieved by a blend of Indigenous wisdom with scientific work.
During Newsome’s 16 field trips to the centre between 1959 and 1962 he shot 2000 Red Kangaroos! That was the way in those days—even small mammals were usually caught using break-back traps! I wonder how such research propositions would have fared in today’s environment where work must be approved by independent animal ethic committees?
This is an important book which needs to be read in the context of when it was written and when the research was carried out. In his foreword, Hugh Tyndale-Biscoe believes this book rates with other natural history classics such as Ratcliffe’s Flying Fox and Drifting Sand, Frith’s The Mallee Fowl: the bird that makes an incubator and Rolls’ They All Ran Wild. This may be an exaggeration (it is a slim volume) but certainly field naturalists will enjoy reading about the early journey Newsome took in his field work career.
Frith HJ (1962) The Mallee Fowl: the bird that makes an incubator. (Angus and Robertson: Sydney)
Ratcliffe F (1938) Flying Fox and drifting sand. (Chatto and Windus: London)
Rolls EC (1969) They all ran wild: the story of pests on the land in Australia. (Angus and Robertson: Sydney)”
Thanks Rob for the review.
Golden jackal expansion in Europe
In a recent paper we explored whether the expansion of golden jackal populations in Europe is linked to the widespread extirpation of the grey wolf.
Below is a copy of the abstract and you can view the open access paper HERE
Top-down suppression by apex predators can limit the abundance and spatial distribution of mesopredators. However, this phenomenon has not been studied over long time periods in human-dominated landscapes, where the strength of this process might be limited. Here, we used a multi-scale approach to analyse interactions between two canids in the human-dominated landscapes of Europe. We tested the hypothesis that the range expansion of golden jackals (Canis aureus) was triggered by intensive persecution and resulting decline of the apex predator, the grey wolf (Canis lupus). To do so, we (1) reviewed literature to reconstruct the historic changes in the distribution and abundance of the two canid species on the continental scale, (2) analysed hunting data patterns for both species in Bulgaria and Serbia, and (3) surveyed jackal persistence in eight study areas that became re-colonized by territorial wolves. The observed trends were generally consistent with the predictions of the mesopredator release hypothesis and supported the existence of top-down suppression by wolves on jackals. We observed inverse patterns of relative abundance and distribution for both canid species at various spatial scales. In most (seven out of eight) cases of wolf re-colonization of jackal territories, jackals disappeared or were displaced out or to the periphery of the newly established wolf home-ranges. We suggest that wolf extermination could be the key driver that enabled the expansion of jackals throughout Europe. Our results also indicate that top-down suppression may be weakened where wolves are intensively persecuted by humans or occur at reduced densities in human-dominated landscapes, which has important management implications and warrants further research.
Research Update – Dingo Reintroduction
In a recent paper and opinion piece in The Conversation it was argued that the case for dingo reintroduction (e.g. see HERE) in Australia is weak.
The arguments focused on two key points:
- That dingo reintroduction proposals have been inspired largely by the reintroduction of wolves into Yellowstone National Park.
- That unstable climates in Australia will make if difficult for dingoes to exert strong effects on ecosystems via trophic cascades.
(see here for a definition of a trophic cascade, and below for an example of a dingo-induced trophic cascade).
In a paper published in the journal Food Webs, we responded to these criticisms and argued that (1) the case for dingo reintroduction has never been solely based on the reintroduction of wolves into Yellowstone National Park, and (2) that the climatic circumstances under which dingoes can provide net positive effects on ecosystems via trophic cascades are those that typically prevail in Australia.
We concluded that the case for dingo reintroduction in Australia remains strong, and urge managers and decision makers to consider the mounting evidence that dingoes can have positive effects on ecosystems before deciding whether or not to reintroduce dingoes into ecosystems where they have been extirpated by humans.
A dingo-induced trophic cascade (solid arrows).
If dingoes suppress large herbivores (e.g. kangaroos and emus), then grass and herb biomass is expected to increase. If dingoes suppress lower order predators (e.g. foxes and cats), then numbers of small mammals (e.g. mice), reptiles (e.g. goannas), and birds (e.g. parrots) are expected to increase. Invertebrates also may respond to improved vegetation conditions and contribute to soil quality. However, the strength of all interactions may be influenced by the extent of rainfall and fires (hashed arrows). Numbers represent the predicted sequence of events based on trophic cascade theory.
Research Update – Feral Cats
Since my last post I have been a co-author on two research papers on feral cats.
1. Legge S, et al (including Newsome TM) (2017) Enumerating a continental-scale threat: how many feral cats are in Australia? (Biological Conservation)
In this paper we found that feral cats cover over 99.8% of Australia’s land area, including almost 80% of the area of our islands.
“Australia’s total feral cat population fluctuates between 2.1 million when times are lean, up to 6.3 million when widespread rain results in plenty of available prey,” explains the lead author Dr Sarah Legge from The University of Queensland.
Furthermore, cat densities were found to be the same both inside and outside conservation reserves, such as National Parks, showing that declaring protected areas alone is not enough to safeguard our native wildlife.
This paper has now become the most heavily ‘e-cited’ paper in the journal Biological Conservation.
A full summary of the media generated can be found HERE
2. Molsher R, Newsome AE, Newsome TM, Dickman CR (2017) Mesopredator management: effects of red fox control on the abundance, diet and use of space by feral cats (PLOS ONE)
In this paper we investigated interactions between red foxes and feral cats in south-eastern Australia.
We used a fox-removal experiment to assess whether foxes affect cat abundance, diet, home-range and habitat use.
The results provide little indication that cats responded numerically to the fox removal, but suggest that the fox affects some aspects of cat resource use. In particular, where foxes were removed cats increased their consumption of invertebrates and carrion, decreased their home range size and foraged more in open habitats.
The results suggest that fox control programs could lead to changes in the way that cats interact with co-occurring prey, and that some prey may become more vulnerable to cat predation in open habitats after foxes have been removed.
The paper was featured in the NRM Research and Innovation Network weekly updates.