1
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Ehlers L, Palm E, Herriges J, Bentzen T, Suitor M, Joly K, Millspaugh J, Donnelly P, Gross J, Wells J, Larue B, Hebblewhite M. A taste of space: Remote animal observations and discrete-choice models provide new insights into foraging and density dynamics for a large subarctic herbivore. J Anim Ecol 2024. [PMID: 38773852 DOI: 10.1111/1365-2656.14109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 04/11/2024] [Indexed: 05/24/2024]
Abstract
Competition for resources and space can drive forage selection of large herbivores from the bite through the landscape scale. Animal behaviour and foraging patterns are also influenced by abiotic and biotic factors. Fine-scale mechanisms of density-dependent foraging at the bite scale are likely consistent with density-dependent behavioural patterns observed at broader scales, but few studies have directly tested this assertion. Here, we tested if space use intensity, a proxy of spatiotemporal density, affects foraging mechanisms at fine spatial scales similarly to density-dependent effects observed at broader scales in caribou. We specifically assessed how behavioural choices are affected by space use intensity and environmental processes using behavioural state and forage selection data from caribou (Rangifer tarandus granti) observed from GPS video-camera collars using a multivariate discrete-choice modelling framework. We found that the probability of eating shrubs increased with increasing caribou space use intensity and cover of Salix spp. shrubs, whereas the probability of eating lichen decreased. Insects also affected fine-scale foraging behaviour by reducing the overall probability of eating. Strong eastward winds mitigated negative effects of insects and resulted in higher probabilities of eating lichen. At last, caribou exhibited foraging functional responses wherein their probability of selecting each food type increased as the availability (% cover) of that food increased. Space use intensity signals of fine-scale foraging were consistent with density-dependent responses observed at larger scales and with recent evidence suggesting declining reproductive rates in the same caribou population. Our results highlight potential risks of overgrazing on sensitive forage species such as lichen. Remote investigation of the functional responses of foraging behaviours provides exciting future applications where spatial models can identify high-quality habitats for conservation.
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Affiliation(s)
- L Ehlers
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
| | - E Palm
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
| | - J Herriges
- Bureau of Land Management, Fairbanks, Alaska, USA
| | - T Bentzen
- Alaska Department of Fish and Game, Fairbanks, Alaska, USA
| | - M Suitor
- Yukon Government, Yukon, Yukon Territory, Canada
| | - K Joly
- National Park Service, Yukon-Charley Rivers National Preserve, Fairbanks, Alaska, USA
| | - J Millspaugh
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
| | - P Donnelly
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
| | - J Gross
- Alaska Department of Fish and Game, Tok, Alaska, USA
| | - J Wells
- Alaska Department of Fish and Game, Tok, Alaska, USA
| | - B Larue
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
| | - M Hebblewhite
- Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana, USA
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2
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Parsons IL, Karisch BB, Stone AE, Webb SL, Norman DA, Street GM. Machine Learning Methods and Visual Observations to Categorize Behavior of Grazing Cattle Using Accelerometer Signals. SENSORS (BASEL, SWITZERLAND) 2024; 24:3171. [PMID: 38794023 PMCID: PMC11124846 DOI: 10.3390/s24103171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/18/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024]
Abstract
Accelerometers worn by animals produce distinct behavioral signatures, which can be classified accurately using machine learning methods such as random forest decision trees. The objective of this study was to identify accelerometer signal separation among parsimonious behaviors. We achieved this objective by (1) describing functional differences in accelerometer signals among discrete behaviors, (2) identifying the optimal window size for signal pre-processing, and (3) demonstrating the number of observations required to achieve the desired level of model accuracy,. Crossbred steers (Bos taurus indicus; n = 10) were fitted with GPS collars containing a video camera and tri-axial accelerometers (read-rate = 40 Hz). Distinct behaviors from accelerometer signals, particularly for grazing, were apparent because of the head-down posture. Increasing the smoothing window size to 10 s improved classification accuracy (p < 0.05), but reducing the number of observations below 50% resulted in a decrease in accuracy for all behaviors (p < 0.05). In-pasture observation increased accuracy and precision (0.05 and 0.08 percent, respectively) compared with animal-borne collar video observations.
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Affiliation(s)
- Ira Lloyd Parsons
- Quantitative Ecology and Spatial Technologies Laboratory, Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS 39762, USA; (D.A.N.); (G.M.S.)
- West River Research and Extension Center, Department of Animal Science, South Dakota State University, Rapid City, SD 57703, USA
| | - Brandi B. Karisch
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA; (B.B.K.); (A.E.S.)
| | - Amanda E. Stone
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA; (B.B.K.); (A.E.S.)
| | - Stephen L. Webb
- Texas A&M Natural Resources Institute and Department of Rangeland, Wildlife, and Fisheries Management, Texas A&M University, College Station, TX 77843, USA;
| | - Durham A. Norman
- Quantitative Ecology and Spatial Technologies Laboratory, Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS 39762, USA; (D.A.N.); (G.M.S.)
| | - Garrett M. Street
- Quantitative Ecology and Spatial Technologies Laboratory, Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Starkville, MS 39762, USA; (D.A.N.); (G.M.S.)
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3
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Newsome T, Cairncross R, Cunningham CX, Spencer EE, Barton PS, Ripple WJ, Wirsing AJ. Scavenging with invasive species. Biol Rev Camb Philos Soc 2024; 99:562-581. [PMID: 38148253 DOI: 10.1111/brv.13035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/19/2023] [Accepted: 11/22/2023] [Indexed: 12/28/2023]
Abstract
Carrion acts as a hotspot of animal activity within many ecosystems globally, attracting scavengers that rely on this food source. However, many scavengers are invasive species whose impacts on scavenging food webs and ecosystem processes linked to decomposition are poorly understood. Here, we use Australia as a case study to review the extent of scavenging by invasive species that have colonised the continent since European settlement, identify the factors that influence their use of carcasses, and highlight the lesser-known ecological effects of invasive scavengers. From 44 published studies we identified six invasive species from 48 vertebrates and four main groups of arthropods (beetles, flies, ants and wasps) that scavenge. Invasive red foxes (Vulpes vulpes), domestic dogs (Canis familiaris), feral pigs (Sus scrofa), black rats (Rattus rattus) and feral cats (Felis catus) were ranked as highly common vertebrate scavengers. Invasive European wasps (Vespula germanica) are also common scavengers where they occur. We found that the diversity of native vertebrate scavengers is lower when the proportion of invasive scavengers is higher. We highlight that the presence of large (apex) native vertebrate scavengers can decrease rates of scavenging by invasive species, but that invasive scavengers can monopolise carcass resources, outcompete native scavengers, predate other species around carcass resources and even facilitate invasion meltdowns that affect other species and ecological processes including altered decomposition rates and nutrient cycling. Such effects are likely to be widespread where invasive scavengers occur and suggest a need to determine whether excessive or readily available carcass loads are facilitating or exacerbating the impacts of invasive species on ecosystems globally.
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Affiliation(s)
- Thomas Newsome
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Rhys Cairncross
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Calum X Cunningham
- School of Environmental and Forest Sciences, University of Washington, College of the Environment, Box 352100, Seattle, WA, 98195-2100, USA
| | - Emma E Spencer
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Philip S Barton
- School of Life and Environmental Science, Deakin University, Geelong, Victoria, 3216, Australia
| | - William J Ripple
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, College of the Environment, Box 352100, Seattle, WA, 98195-2100, USA
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4
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English HM, Börger L, Kane A, Ciuti S. Advances in biologging can identify nuanced energetic costs and gains in predators. MOVEMENT ECOLOGY 2024; 12:7. [PMID: 38254232 PMCID: PMC10802026 DOI: 10.1186/s40462-024-00448-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024]
Abstract
Foraging is a key driver of animal movement patterns, with specific challenges for predators which must search for mobile prey. These patterns are increasingly impacted by global changes, principally in land use and climate. Understanding the degree of flexibility in predator foraging and social strategies is pertinent to wildlife conservation under global change, including potential top-down effects on wider ecosystems. Here we propose key future research directions to better understand foraging strategies and social flexibility in predators. In particular, rapid continued advances in biologging technology are helping to record and understand dynamic behavioural and movement responses of animals to environmental changes, and their energetic consequences. Data collection can be optimised by calibrating behavioural interpretation methods in captive settings and strategic tagging decisions within and between social groups. Importantly, many species' social systems are increasingly being found to be more flexible than originally described in the literature, which may be more readily detectable through biologging approaches than behavioural observation. Integrating the effects of the physical landscape and biotic interactions will be key to explaining and predicting animal movements and energetic balance in a changing world.
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Affiliation(s)
- Holly M English
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland.
| | - Luca Börger
- Department of Biosciences, Swansea University, Swansea, UK
| | - Adam Kane
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
| | - Simone Ciuti
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
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5
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Lewis AC, Hughes C, Rogers TL. Living in human-modified landscapes narrows the dietary niche of a specialised mammalian scavenger. Sci Rep 2023; 13:3582. [PMID: 36869089 PMCID: PMC9984462 DOI: 10.1038/s41598-023-30490-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Anthropogenic impacts on carnivores can be complex, posing numerous threats to many species, yet also benefits to those able to exploit certain resources. This balancing act is particularly precarious for those adapters that exploit dietary resources provided by humans, but still require other resources only available in native habitat. Here we measure the dietary niche of one such species, the Tasmanian devil (Sarcophilus harrisii), a specialised mammalian scavenger, across an anthropogenic habitat gradient stretching from cleared pasture to undisturbed rainforest. Populations inhabiting areas of greater disturbance showed restricted dietary niches, suggesting that all individuals fed on similar food items, even within regenerated native forest. Populations in undisturbed rainforest habitats had comparatively broad diets and showed evidence of niche partitioning by body size, which may reduce intraspecific competition. Despite the potential benefits of reliable access to high-quality food items in anthropogenically-modified habitats, the constrained niches we observed may be harmful, indicating altered behaviours and potentially increasing the rate of fights between individuals over food. This is of particular concern for a species at risk of extinction due to a deadly cancer primarily transmitted through aggressive interactions. The lack of diversity in devil diets within regenerated native forest compared to those in old-growth rainforest also indicates the conservation value of the latter for both the devil and the species which they consume.
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Affiliation(s)
- Anna C Lewis
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
- The Carnivore Conservancy, Ulverstone, TAS, Australia.
| | - Channing Hughes
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
- The Carnivore Conservancy, Ulverstone, TAS, Australia
| | - Tracey L Rogers
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
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6
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McGrane SJ, Gibbs M, Hernangomez de Alvaro C, Dunlop N, Winnig M, Klebansky B, Waller D. Umami taste perception and preferences of the domestic cat (Felis catus), an obligate carnivore. Chem Senses 2023; 48:bjad026. [PMID: 37551788 PMCID: PMC10468298 DOI: 10.1093/chemse/bjad026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 08/09/2023] Open
Abstract
The domestic cat (Felis catus) is an obligate carnivore, and as such has a meat-based diet. Several studies on the taste perception of cats have been reported, indicating that their sense of taste has evolved based on their carnivorous diet. Here, we propose that umami (mediated by Tas1r1-Tas1r3) is the main appetitive taste modality for the domestic cat by characterizing the umami taste of a range of nucleotides, amino acids, and their mixtures for cats obtained using complementary methods. We show for the first time that cats express Tas1r1 in taste papillae. The cat umami receptor responds to a range of nucleotides as agonists, with the purine nucleotides having the highest activity. Their umami receptor does not respond to any amino acids alone; however, 11 l-amino acids with a range of chemical characteristics act as enhancers in combination with a nucleotide. l-Glutamic acid and l-Aspartic acid are not active as either agonists or enhancers of the cat umami receptor due to changes in key binding residues at positions 170 and 302. Overall, cats have an appetitive behavioral response for nucleotides, l-amino acids, and their mixtures. We postulate that the renowned palatability of tuna for cats may be due, at least in part, to its specific combination of high levels of inosine monophosphate and free l-Histidine that produces a strong synergistic umami taste enhancement. These results demonstrate the critical role that the umami receptor plays in enabling cats to detect key taste compounds present in meat.
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Affiliation(s)
- Scott J McGrane
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, United Kingdom
| | - Matthew Gibbs
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, United Kingdom
| | - Carlos Hernangomez de Alvaro
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, United Kingdom
| | - Nicola Dunlop
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, United Kingdom
| | - Marcel Winnig
- AXXAM GmbH, Byk-Gulden Str.2, 78467 Constance, Germany
| | - Boris Klebansky
- BioPredict, Inc., 4 Adele Avenue, Demarest, NJ 07627, United States
| | - Daniel Waller
- Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wolds, Melton Mowbray, Leicestershire LE14 4RT, United Kingdom
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7
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Lewis AC, Hughes C, Rogers TL. Effects of intraspecific competition and body mass on diet specialization in a mammalian scavenger. Ecol Evol 2022; 12:e8338. [PMID: 35126999 PMCID: PMC8794717 DOI: 10.1002/ece3.8338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/26/2021] [Accepted: 10/18/2021] [Indexed: 11/08/2022] Open
Abstract
Animals that rely extensively on scavenging rather than hunting must exploit resources that are inherently patchy, dangerous, or subject to competition. Though it may be expected that scavengers should therefore form opportunistic feeding habits in order to survive, a broad species diet may mask specialization occurring at an individual level. To test this, we used stable isotope analysis to analyze the degree of specialization in the diet of the Tasmanian devil, one of few mammalian species to develop adaptations for scavenging. We found that the majority of individuals were dietary specialists, indicating that they fed within a narrow trophic niche despite their varied diet as a species. Even in competitive populations, only small individuals could be classified as true trophic generalists; larger animals in those populations were trophic specialists. In populations with reduced levels of competition, all individuals were capable of being trophic specialists. Heavier individuals showed a greater degree of trophic specialization, suggesting either that mass is an important driver of diet choice or that trophic specialization is an efficient foraging strategy allowing greater mass gain. Devils may be unique among scavenging mammals in the extent to which they can specialize their diets, having been released from the competitive pressure of larger carnivores.
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Affiliation(s)
- Anna C. Lewis
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental SciencesUniversity of New South WalesSydneyAustralia
- The Carnivore ConservancyUlverstoneTasmaniaAustralia
| | - Channing Hughes
- The Carnivore ConservancyUlverstoneTasmaniaAustralia
- School of Life and Environmental SciencesThe University of SydneySydneyNew South WalesAustralia
| | - Tracey L. Rogers
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental SciencesUniversity of New South WalesSydneyAustralia
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental SciencesUniversity of New South WalesSydneyAustralia
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8
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Lahoz-Monfort JJ, Magrath MJL. A Comprehensive Overview of Technologies for Species and Habitat Monitoring and Conservation. Bioscience 2021; 71:1038-1062. [PMID: 34616236 PMCID: PMC8490933 DOI: 10.1093/biosci/biab073] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The range of technologies currently used in biodiversity conservation is staggering, with innovative uses often adopted from other disciplines and being trialed in the field. We provide the first comprehensive overview of the current (2020) landscape of conservation technology, encompassing technologies for monitoring wildlife and habitats, as well as for on-the-ground conservation management (e.g., fighting illegal activities). We cover both established technologies (routinely deployed in conservation, backed by substantial field experience and scientific literature) and novel technologies or technology applications (typically at trial stage, only recently used in conservation), providing examples of conservation applications for both types. We describe technologies that deploy sensors that are fixed or portable, attached to vehicles (terrestrial, aquatic, or airborne) or to animals (biologging), complemented with a section on wildlife tracking. The last two sections cover actuators and computing (including web platforms, algorithms, and artificial intelligence).
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Affiliation(s)
- José J Lahoz-Monfort
- School of Ecosystem and Forest Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael J L Magrath
- Wildlife Conservation and Science, Zoos Victoria and with the School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
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9
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Lazenby BT, Mooney NJ, Dickman CR. Raiders of the last ark: the impacts of feral cats on small mammals in Tasmanian forest ecosystems. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02362. [PMID: 33899303 DOI: 10.1002/eap.2362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/01/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Feral individuals of the cat Felis catus are recognized internationally as a threat to biodiversity. Open, non-insular systems support a large proportion of the world's biodiversity, but the population-level impacts of feral cats in these systems are rarely elucidated. This limits prioritization and assessment of the effectiveness of management interventions. We quantified the predatory impact of feral cats on small mammals in open, non-insular forest systems in Tasmania, Australia in the context of other factors hypothesized to affect small mammal densities and survival, namely the density of a native carnivore, co-occurring small mammals, and rainfall. Change in feral cat density was the most important determinant of small mammal density and survival. We calculated that, on average, a 50% reduction in feral cat density could result in 25% and 10% increases in the density of the swamp rat Rattus lutreolus and long-tailed mouse Pseudomys higginsi, respectively. Low-level culling of feral cats that we conducted on two of our four study sites to experimentally alter feral cat densities revealed that swamp rat survival was highest when feral cat densities were stable. We conclude that feral cats exert downward pressure on populations of indigenous small mammals in temperate forest systems. However, alleviating this downward pressure on prey by culling a large proportion of the feral cat population is difficult as current methods for reducing feral cat populations in cool temperate forest systems are ineffective, and potentially even counterproductive. We suggest using an adaptive approach that regularly and robustly monitors how feral cats and small mammals respond to management interventions that are intended to conserve vulnerable prey species.
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Affiliation(s)
- B T Lazenby
- Department of Primary Industries, Parks, Water and Environment, 134 Macquarie Street, Hobart, Tasmania, Australia
| | - N J Mooney
- Tasmanian Museum and Art Gallery, Dunn Place, Hobart, Tasmania, Australia
| | - C R Dickman
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, 2006, Australia
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10
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Landy S, Peralta S, Vogelnest L, Fiani N. The Macroscopic and Radiographic Skull and Dental Pathology of the Tasmanian Devil ( Sarcophilus harrisii). Front Vet Sci 2021; 8:693578. [PMID: 34179178 PMCID: PMC8222698 DOI: 10.3389/fvets.2021.693578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
While the gross skull and dental morphology, masticatory biomechanics, dental eruption patterns, and radiographic dental anatomy has been described in the Tasmanian devil (Sarcophilus harrisii), to date no studies have comprehensively examined the prevalence and appearance of pathologic processes affecting their skulls and dentition. As such, the aim of this study was to describe macroscopic and radiographic anatomy and identify the prevalence of anatomic variations and pathological processes in Tasmanian devil dentition and skulls. To do so, anatomical and pathological findings were documented in Tasmanian devil skulls using photography and dental radiography. Assessment of skull trauma, anatomical and developmental abnormalities, periodontitis, endodontic disease, and tooth resorption was performed. A total of 28 Tasmanian devil skulls containing 1,028 teeth were examined. Evidence of postmortem trauma was common. The most common positional abnormality was palatal or buccal rotation of the premolar teeth. While the alveolar bone margin was commonly positioned apically to the cementoenamel junction (98.2%), only 14.2% demonstrated evidence of periodontitis. Tooth fractures were common, affecting 27 skulls, however radiographic signs of endodontic disease were only noted in 4.5% of affected teeth, as was non-inflammatory root resorption (2.0%). A wider root canal width, which was used as a criterion for age determination, was associated with smaller skull dimensions, incompletely erupted teeth, and subjectively less fusion of the mandibular symphysis. Through an improved understanding of what constitutes normal anatomy and the appearance and frequency of pathologic processes that affect the skulls and teeth, this knowledge can help develop a foundation for understanding the oral health and management of live animals for this endangered species.
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Affiliation(s)
- Shanna Landy
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Santiago Peralta
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Larry Vogelnest
- Taronga Conservation Society Australia, Mosman, NSW, Australia
| | - Nadine Fiani
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
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11
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Bell O, Jones ME, Cunningham CX, Ruiz‐Aravena M, Hamilton DG, Comte S, Hamede RK, Bearhop S, McDonald RA. Isotopic niche variation in Tasmanian devils Sarcophilus harrisii with progression of devil facial tumor disease. Ecol Evol 2021; 11:8038-8053. [PMID: 34188870 PMCID: PMC8216929 DOI: 10.1002/ece3.7636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022] Open
Abstract
Devil facial tumor disease (DFTD) is a transmissible cancer affecting Tasmanian devils Sarcophilus harrisii. The disease has caused severe population declines and is associated with demographic and behavioral changes, including earlier breeding, younger age structures, and reduced dispersal and social interactions. Devils are generally solitary, but social encounters are commonplace when feeding upon large carcasses. DFTD tumors can disfigure the jaw and mouth and so diseased individuals might alter their diets to enable ingestion of alternative foods, to avoid conspecific interactions, or to reduce competition. Using stable isotope analysis (δ13C and δ15N) of whiskers, we tested whether DFTD progression, measured as tumor volume, affected the isotope ratios and isotopic niches of 94 infected Tasmanian devils from six sites in Tasmania, comprising four eucalypt plantations, an area of smallholdings and a national park. Then, using tissue from 10 devils sampled before and after detection of tumors and 8 devils where no tumors were detected, we examined whether mean and standard deviation of δ13C and δ15N of the same individuals changed between healthy and diseased states. δ13C and δ15N values were generally not related to tumor volume in infected devils, though at one site, Freycinet National Park, δ15N values increased significantly as tumor volume increased. Infection with DFTD was not associated with significant changes in the mean or standard deviation of δ13C and δ15N values in individual devils sampled before and after detection of tumors. Our analysis suggests that devils tend to maintain their isotopic niche in the face of DFTD infection and progression, except where ecological conditions facilitate a shift in diets and feeding behaviors, demonstrating that ecological context, alongside disease severity, can modulate the behavioral responses of Tasmanian devils to DFTD.
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Affiliation(s)
- Olivia Bell
- Environment and Sustainability InstituteUniversity of ExeterPenrynUK
| | - Menna E. Jones
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
| | | | - Manuel Ruiz‐Aravena
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
- Department of Microbiology and ImmunologyMontana State UniversityBozemanMTUSA
| | - David G. Hamilton
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Sebastien Comte
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
- Vertebrate Pest Research UnitNSW Department of Primary IndustriesOrangeNSWAustralia
| | - Rodrigo K. Hamede
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Stuart Bearhop
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
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12
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Nazir S, Kaleem M. Advances in image acquisition and processing technologies transforming animal ecological studies. ECOL INFORM 2021. [DOI: 10.1016/j.ecoinf.2021.101212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Andersen GE, Johnson CN, Jones ME. Space use and temporal partitioning of sympatric Tasmanian devils and spotted‐tailed quolls. AUSTRAL ECOL 2020. [DOI: 10.1111/aec.12865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Georgina E. Andersen
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania7001Australia
| | - Christopher N. Johnson
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania7001Australia
- School of Biological Sciences and Australian research Council Centre for Australian Biodiversity and Heritage University of Tasmania Hobart Tasmania Australia
| | - Menna E. Jones
- School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tasmania7001Australia
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