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Shannon G, Valle S, Shuttleworth CM. Capturing red squirrels ( Sciurus vulgaris) on camera: A cost-effective approach for monitoring relative abundance and habitat preference. Ecol Evol 2023; 13:e10536. [PMID: 37794876 PMCID: PMC10546084 DOI: 10.1002/ece3.10536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/04/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023] Open
Abstract
Effective methods for monitoring animal populations are crucial for species conservation and habitat management. Motion-activated cameras provide an affordable method for passively surveying animal presence across the landscape but have mainly been used for studying large-bodied mammals. This paper explores the relative abundance and habitat preferences of red squirrels (Sciurus vulgaris) in coniferous forests using cameras and live trapping. The study was conducted in two forests (Newborough and Pentraeth) on Anglesey, North Wales, with a total of 50 sampling locations across four habitat categories. Detailed woodland structure and composition data were gathered around each sampling location. We found a strong positive correlation between the number of individual red squirrels live trapped over 10 days with the number of camera images of squirrels recorded during a previous 5-day period. The time interval between camera deployment and the first recorded image of a red squirrel showed a significant negative correlation with the number of individuals live trapped. Red squirrel relative abundance was negatively related to forest canopy openness, while the presence of Scots pine and increased tree species diversity were positively associated with the relative abundance of squirrels. There was also a strong site difference with lower relative abundance at Newborough compared with Pentraeth, which likely reflects the heavy thinning of mature forest at Newborough reducing tree crown connectivity. The results show that remotely activated cameras are an effective method for monitoring red squirrel populations across varying animal densities. The cameras also provided crucial information on red squirrel habitat preferences that can aid in woodland management and conservation efforts. Cameras have great potential to collect data on the population status of other small mammals, but it is essential that these methods are validated on a species-by-species basis.
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Affiliation(s)
| | - Simon Valle
- School of Natural SciencesBangor UniversityBangorUK
- IUCN Species Survival Commission Conservation Planning Specialist GroupSt. PaulMinnesotaUSA
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2
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Everest DJ, Green C, Dastjerdi A, Davies H, Cripps R, McKinney C, Podgornik G, Stinson M, O'Hare S, Sapsford B, Mill A, Van der Waal Z, Robinson N, Trotter S, Shuttleworth CM. Opportunistic viral surveillance confirms the ongoing disease threat grey squirrels pose to sympatric red squirrel populations in the UK. Vet Rec 2023; 192:e2834. [PMID: 37024300 DOI: 10.1002/vetr.2834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/29/2022] [Accepted: 03/01/2023] [Indexed: 04/08/2023]
Abstract
BACKGROUND Red Squirrels United was a UK landscape-scale grey squirrel management programme undertaken between 2016 and 2020. METHODS A total of 11034 grey squirrels were removed by culling, with 1506 necropsied and 1405 suitable for adenovirus (AdV) or squirrelpox virus (SQPV) quantitative PCR (qPCR) analysis. Spleen, lip or hair were extracted, and DNA was isolated, with samples tested in duplicate by qPCR. RESULTS Of 1378 tissue samples, 43% were positive for AdV and 10% for SQPV. Of 1031 hair samples, 11% were positive for AdV and 10% for SQPV. Overall, 762 of 1405 (54%) animals were positive for one or both viruses. LIMITATIONS Ad hoc sampling was undertaken from limited geographical areas but provided the only dataset from that period, instead of extrapolating from historical data. CONCLUSIONS The grey squirrel is an asymptomatic reservoir host for AdV and SQPV. Interspecific infection transmission potential is demonstrated. Grey squirrel management by culling is essential for mainland red squirrel viability until other suitable management tools are available.
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Affiliation(s)
| | - Chalin Green
- Animal and Plant Health Agency-Weybridge, Addlestone, UK
| | | | - Hannah Davies
- Animal and Plant Health Agency-Weybridge, Addlestone, UK
| | - Rachel Cripps
- Lancashire Wildlife Trust, Seaforth Nature Reserve, Liverpool, UK
| | | | | | | | - Simon O'Hare
- Northumberland Wildlife Trust, Newcastle Upon Tyne, UK
| | | | - Aileen Mill
- Centre for Wildlife Management, School of Biology, Newcastle University, Newcastle Upon Tyne, UK
| | - Zelda Van der Waal
- Centre for Wildlife Management, School of Biology, Newcastle University, Newcastle Upon Tyne, UK
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3
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Wauters LA, Lurz PWW, Santicchia F, Romeo C, Ferrari N, Martinoli A, Gurnell J. Interactions between native and invasive species: A systematic review of the red squirrel-gray squirrel paradigm. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1083008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
The eastern gray squirrel (Sciurus carolinensis) has been labeled as one of the 100 worst invasive alien species by the IUCN. In Europe, the species has been introduced to Britain, Ireland and Italy, and its subsequent spread has resulted in wide-scale extinction of native Eurasian red squirrels (Sciurus vulgaris) from the areas colonized by the gray squirrel. This replacement of a native by an alien competitor is one of the best documented cases of the devastating effects of biological invasions on native fauna. To understand how this replacement occurs, we present a systematic review of the literature on competition and interactions between red and gray squirrels. We describe the patterns of red and gray squirrel distribution in those parts of Europe where gray squirrels occur and summarize the evidence on the different processes and mechanisms determining the outcome of competition between the native and alien species including the influence of predators and pathogens. Some of the drivers behind the demise of the red squirrel have been intensively studied and documented in the past 30 years, but recent field studies and mathematical models revealed that the mechanisms underlying the red-gray paradigm are more complex than previously thought and affected by landscape-level processes. Therefore, we consider habitat type and multi-species interactions, including host-parasite and predator-prey relationships, to determine the outcome of the interaction between the two species and to better address gray squirrel control efforts.
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4
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A genetic analysis of grey squirrel (Sciurus carolinensis) populations in Ireland. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02782-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
AbstractThe grey squirrel (Sciurus carolinensis) is an invasive rodent in Ireland that has had detrimental impacts on the native Irish red squirrel (S. vulgaris) as well as on silviculture. This invasive species spread rapidly throughout Ireland, but in recent years appears to be declining in certain areas of the country. This study analysed the genetic profile of grey squirrel populations in Ireland to gain insight into their introduction, evolutionary history in Ireland, and vulnerability to management strategies. The genetic diversity and population structure of eight grey squirrel populations in Ireland was assessed using 11 species-specific microsatellite loci, and was compared to a small population from Tennessee, U.S.A., part of the native range of the grey squirrel. This is the first time these microsatellite markers developed specifically for grey squirrels have been used to study the species in Ireland. We found low to moderate genetic diversity overall across Irish populations as well as the presence of inbreeding. One population in particular, (in Co. Kildare), was differentiated from all other populations, which could indicate genetic isolation between Irish populations or a secondary introduction of S. carolinensis to Ireland.
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5
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Shuttleworth CM, Everest D, Holmes P, Bell S, Cripps R. An Opportunistic Assessment of the Impact of Squirrelpox Disease Outbreaks upon a Red Squirrel Population Sympatric with Grey Squirrels in Wales. Animals (Basel) 2022; 12:ani12010099. [PMID: 35011205 PMCID: PMC8749610 DOI: 10.3390/ani12010099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/27/2021] [Accepted: 12/29/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary In Europe, squirrelpox virus is carried by non-native grey squirrels and spread into native red squirrel populations. The virus causes a large proportion of infected red squirrels to die and contributes to local declines and the replacement by grey squirrels. There are relatively few published studies quantifying the impact of disease amongst red squirrels. We present findings from a short-term study in north Wales, United Kingdom. Abstract Native red squirrels (Sciurus vulgaris) persisted in the coastal mainland woodlands of northern Gwynedd whilst sympatric with an invasive grey squirrel (Sciurus carolinensis) population suppressed by culling. Squirrelpox disease in the red squirrel population was recorded in 2017 and 2020/21. An autumn 2020 outbreak was associated with only 17.4% of animals caught and marked in the preceding June known to be present in March 2021. Despite an opportunistic data collection lacking the rigour of empirical experimental design, we observed low local survival rates similar to previously published accounts reported during major squirrelpox outbreaks. The use of a conservation dog to detect red squirrel carcasses resulted in positive detection and confirmation of a temporal and spatial expansion of one disease outbreak. The study is the first in Wales to use conservation dogs and the findings reinforce the vital strategic importance of geographical isolation reducing sympatry of red with grey squirrels in European regions where the introduced congener is a source of the squirrelpox infection.
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Affiliation(s)
| | | | - Paul Holmes
- APHA Shrewsbury, Veterinary Investigation Centre, Shrewsbury SY1 4HD, UK; (P.H.); (S.B.)
| | - Suzi Bell
- APHA Shrewsbury, Veterinary Investigation Centre, Shrewsbury SY1 4HD, UK; (P.H.); (S.B.)
| | - Rachel Cripps
- Lancashire Wildlife Trust, Bamber Bridge PR5 6BY, UK;
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6
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The Patterns and Causes of Dermatitis in Terrestrial and Semi-Aquatic Mammalian Wildlife. Animals (Basel) 2021; 11:ani11061691. [PMID: 34204062 PMCID: PMC8228222 DOI: 10.3390/ani11061691] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/03/2021] [Indexed: 12/26/2022] Open
Abstract
Causative disease and stress agents which manifest as dermatitis in mammals have varying effects on individual animals, from benign irritation and inflammation, to causing morbidity and even mortality. Bacteria, viruses and ectoparasites are all potential causes of dermatitis, and it can be exacerbated by various environmental, genetic and social factors. Furthermore, it is uncertain whether dermatitis is more likely to manifest in already-vulnerable wildlife species. Here, we systematically review the literature for reports of dermatitis in terrestrial and semi-aquatic wild mammalian species, with the goal of determining the biogeographical scale of dermatitis reports, the causes of dermatitis, and whether manifestation of dermatitis is reported more commonly in certain wildlife species or their captivity status (i.e., free-living, in captivity or in a laboratory). We reveal biases in the reporting of dermatitis by a biogeographic realm, with 55% of cases reported in the Nearctic, and towards particular orders of mammals, namely Artiodactyla and Carnivora. Overall, free-living wildlife is almost twice as likely to be reported as having dermatitis than individuals in captivity and six times more likely than individuals in laboratories, which we interpret as owing to exposure to a broader spectrum of parasites in free-ranging individuals, and potential reporting bias in captive individuals. Notably, dermatitis was reported in 23 threatened species, with some species more likely than others to be reported exhibiting clinical signs of dermatitis resulting from underlying health problems. We also find that threatened species are more likely to be reported as having dermatitis in captivity, particularly outside of their endemic home range. This review highlights diverse patterns of dermatological disease causes in captive and free-ranging wildlife, conditions under which they are more likely to be documented, and the need for cross-disciplinary research to ascertain (and so better manage) the varied causes.
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7
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Shuttleworth CM, Brady D, Cross P, Gardner L, Greenwood A, Jackson N, McKinney C, Robinson N, Trotter S, Valle S, Wood K, Hayward MW. Recalibrating risk: Implications of squirrelpox virus for successful red squirrel translocations within mainland
UK. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
| | | | - Paul Cross
- School of Natural Sciences, College Road, Bangor University Gwynedd Wales UK
| | | | - Andrew Greenwood
- Wildlife Vets International, Station House Keighley West Yorkshire UK
| | - Nick Jackson
- National Zoological Society of Wales Colwyn Bay, Conwy UK
| | | | - Nikki Robinson
- The Wildlife Trusts, The Kiln, Waterside Newark, Nottinghamshire UK
| | | | - Simon Valle
- School of Natural Sciences, College Road, Bangor University Gwynedd Wales UK
| | - Kim Wood
- National Zoological Society of Wales Colwyn Bay, Conwy UK
| | - Matt W. Hayward
- School of Environmental and Life Sciences, University of Newcastle Callaghan New South Wales Australia
- Centre for African Conservation Ecology, Nelson Mandela University Port Elizabeth South Africa
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8
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Twining JP, Montgomery WI, Tosh DG. Declining invasive grey squirrel populations may persist in refugia as native predator recovery reverses squirrel species replacement. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13660] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Joshua P. Twining
- School of Biological Sciences Queen's University of Belfast Belfast UK
| | - W. Ian Montgomery
- School of Biological Sciences Queen's University of Belfast Belfast UK
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9
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Mori E, Sala JP, Fattorini N, Menchetti M, Montalvo T, Senar JC. Ectoparasite sharing among native and invasive birds in a metropolitan area. Parasitol Res 2018; 118:399-409. [DOI: 10.1007/s00436-018-6174-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 12/03/2018] [Indexed: 01/25/2023]
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10
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McInnes C. Why do red squirrels die? Vet Rec 2018; 183:500-501. [PMID: 30361223 DOI: 10.1136/vr.k4414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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11
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Romeo C, McInnes CJ, Dale TD, Shuttleworth C, Bertolino S, Wauters LA, Ferrari N. Disease, invasions and conservation: no evidence of squirrelpox virus in grey squirrels introduced to Italy. Anim Conserv 2018. [DOI: 10.1111/acv.12433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Romeo
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
| | | | - T. D. Dale
- Institute of Integrative Biology University of Liverpool Liverpool UK
| | - C. Shuttleworth
- School of Environment, Natural Resources and Geography Bangor University Bangor Gwynedd UK
| | - S. Bertolino
- Department of Life Sciences and Systems Biology Università degli Studi di Torino Torino Italy
| | - L. A. Wauters
- Department of Theoretical and Applied Sciences Università degli Studi dell'Insubria Varese Italy
| | - N. Ferrari
- Department of Veterinary Medicine Università degli Studi di Milano Milan Italy
- Centro di Ricerca Coordinata Epidemiologia e Sorveglianza Molecolare delle Infezioni Università degli Studi di Milano Milan Italy
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12
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Santicchia F, Dantzer B, van Kesteren F, Palme R, Martinoli A, Ferrari N, Wauters LA. Stress in biological invasions: Introduced invasive grey squirrels increase physiological stress in native Eurasian red squirrels. J Anim Ecol 2018; 87:1342-1352. [DOI: 10.1111/1365-2656.12853] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/11/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Francesca Santicchia
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
| | - Ben Dantzer
- Department of Psychology; University of Michigan; Ann Arbor Michigan
- Department of Ecology and Evolutionary Biology; University of Michigan; Ann Arbor Michigan
| | | | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology; Department of Biomedical Sciences; University of Veterinary Medicine Vienna; Vienna Austria
| | - Adriano Martinoli
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
| | - Nicola Ferrari
- Department of Veterinary Sciences and Public Health; Università degli Studi di Milano; Milan Italy
| | - Lucas Armand Wauters
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
- Department of Biology; Evolutionary Ecology Group; University of Antwerp; Wilrijk Belgium
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13
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McGowan N, Scantlebury D, McInnes C, Reid N. Squirrelpox virus antibodies detected in red squirrels. Vet Rec 2018; 182:355. [PMID: 29572422 DOI: 10.1136/vr.k1296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Natasha McGowan
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL
| | - David Scantlebury
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL.,Institute for Global Food Security (IGFS), 13 Stranmillis Road, Belfast BT9 5AF
| | - Colin McInnes
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ
| | - Neil Reid
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL.,Institute for Global Food Security (IGFS), 13 Stranmillis Road, Belfast BT9 5AF
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14
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Dale TD, Watts PC, Jones D, Pounder K, Everest DJ, Begon ME, Chantrey J. Enhancement of wildlife disease surveillance using multiplex quantitative PCR: development of qPCR assays for major pathogens in UK squirrel populations. EUR J WILDLIFE RES 2016; 62:589-599. [PMID: 32214943 PMCID: PMC7088385 DOI: 10.1007/s10344-016-1031-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/22/2016] [Accepted: 07/03/2016] [Indexed: 11/22/2022]
Abstract
Rapid development in polymerase chain reaction (PCR) technology has revolutionised the speed and accuracy of many diagnostic assays. However, comparatively few wildlife epidemiological studies use quantitative PCR (qPCR) for pathogen detection, even fewer employ an internal control, to ensure confidence in negative results, and PCR's ability to multiplex and therefore detect several targets in a single reaction is underutilised. Here, we describe the development of two multiplex qPCR assays for the red and grey squirrel that detect the pathogens squirrelpox virus (SQPV) and adenovirus in squirrels (SADV), both of which cause mortality in the red squirrel. Both assays use a section of the squirrel phosphoglycerate kinase gene as an endogenous internal control that identifies and compensates for both, inadequate sampling or PCR inhibition. Tests on infected squirrel tissue demonstrate that simple swab samples (particularly from distal antebrachial skin) are sufficient to detect and identify the relative quantity of SQPV DNA in both squirrel species, while rectal swabs and blood cell pellets can be used to reliably indicate SADV infection. These assays are sensitive and specific with an endogenous internal control providing confidence in negative results and allowing comparison across laboratories. Using such assays should prove advantageous in wildlife studies with limited resources while allowing the maximum data yield.
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Affiliation(s)
- Timothy D. Dale
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | | | - David Jones
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Kieran Pounder
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | - David J. Everest
- Animal and Plant Health Agency, Weybridge, New Haw, Addlestone, Surrey, KT15 3NB UK
| | - Michael E. Begon
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
| | - Julian Chantrey
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7ZB UK
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15
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Goldstein EA, Butler F, Lawton C. Modeling future range expansion and management strategies for an invasive squirrel species. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1092-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Fiegna C, Dagleish M, Coulter L, Milne E, Meredith A, Finlayson J, Di Nardo A, McInnes C. Host-pathogen dynamics of squirrelpox virus infection in red squirrels (Sciurus vulgaris). Vet Microbiol 2016; 182:18-27. [DOI: 10.1016/j.vetmic.2015.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 11/15/2022]
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17
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Macroparasites of introduced parakeets in Italy: a possible role for parasite-mediated competition. Parasitol Res 2015; 114:3277-81. [PMID: 26025315 DOI: 10.1007/s00436-015-4548-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/19/2015] [Indexed: 10/23/2022]
Abstract
Alien species are considered a cause of biodiversity loss throughout the world. An important but often overlooked form of competition with native species is the parasite-mediated one. Introduced species may bring their own parasites from their native ranges (spillover) or get native parasites from native species, thus increasing the parasites' spread and transmission risk (spillback). Thus, a complete knowledge of parasites hosted by introduced species is important to assess and to possibly prevent impacts. Ring-necked and monk parakeets have been introduced in many European countries, where they established a number of alien reproductive populations. We sampled 21 ring-necked parakeets and 7 monk parakeets from Italy and identified 35 arthropod ectoparasites belonging to five species. Amongst those, one species was native to India (Neopsittaconirmus lybartota), where alien populations of ring-necked parakeet may have been originated, and one species from South America (Paragoniocotes fulvofasciatus), which is typically found of the monk parakeet in its native range. The other three species of arthropod parasites were native to Italy and commonly found on native species, suggesting the possibility of spillback processes.
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18
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Stritch C, Naulty F, Zintl A, Callanan JJ, McCullough M, Deane D, Marnell F, McMahon BJ. Squirrelpox virus reservoir expansion on the east coast of Ireland. EUR J WILDLIFE RES 2015. [DOI: 10.1007/s10344-015-0909-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Tompkins DM, Carver S, Jones ME, Krkošek M, Skerratt LF. Emerging infectious diseases of wildlife: a critical perspective. Trends Parasitol 2015; 31:149-59. [PMID: 25709109 DOI: 10.1016/j.pt.2015.01.007] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 01/07/2015] [Accepted: 01/22/2015] [Indexed: 12/20/2022]
Abstract
We review the literature to distinguish reports of vertebrate wildlife disease emergence with sufficient evidence, enabling a robust assessment of emergence drivers. For potentially emerging agents that cannot be confirmed, sufficient data on prior absence (or a prior difference in disease dynamics) are frequently lacking. Improved surveillance, particularly for neglected host taxa, geographical regions and infectious agents, would enable more effective management should emergence occur. Exposure to domestic sources of infection and human-assisted exposure to wild sources were identified as the two main drivers of emergence across host taxa; the domestic source was primary for fish while the wild source was primary for other taxa. There was generally insufficient evidence for major roles of other hypothesized drivers of emergence.
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Affiliation(s)
| | - Scott Carver
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Menna E Jones
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St, Toronto, ON, M5S 3G5, Canada
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
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20
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Frontier population dynamics of an invasive squirrel species: Do introduced populations function differently than those in the native range? Biol Invasions 2014. [DOI: 10.1007/s10530-014-0787-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Chantrey J, Dale TD, Read JM, White S, Whitfield F, Jones D, McInnes CJ, Begon M. European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface. Ecol Evol 2014; 4:3788-99. [PMID: 25614793 PMCID: PMC4301051 DOI: 10.1002/ece3.1216] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/03/2014] [Accepted: 07/13/2014] [Indexed: 11/17/2022] Open
Abstract
Infectious disease introduced by non-native species is increasingly cited as a facilitator of
native population declines, but direct evidence may be lacking due to inadequate population and
disease prevalence data surrounding an outbreak. Previous indirect evidence and theoretical models
support squirrelpox virus (SQPV) as being potentially involved in the decline of red squirrels
(Sciurus vulgaris) following the introduction of the non-native gray squirrel
(Sciurus carolinensis) to the United Kingdom. The red squirrel is a major UK
conservation concern and understanding its continuing decline is important for any attempt to
mitigate the decline. The red squirrel–gray squirrel system is also exemplary of the
interplay between infectious disease (apparent competition) and direct competition in driving the
replacement of a native by an invasive species. Time series data from Merseyside are presented on
squirrel abundance and squirrelpox disease (SQPx) incidence, to determine the effect of the pathogen
and the non-native species on the native red squirrel populations. Analysis indicates that SQPx in
red squirrels has a significant negative impact on squirrel densities and their population growth
rate (PGR). There is little evidence for a direct gray squirrel impact; only gray squirrel presence
(but not density) proved to influence red squirrel density, but not red squirrel PGR. The dynamics
of red SQPx cases are largely determined by previous red SQPx cases, although previous infection of
local gray squirrels also feature, and thus, SQPV-infected gray squirrels are identified as
potentially initiating outbreaks of SQPx in red squirrels. Retrospective serology indicates that
approximately 8% of red squirrels exposed to SQPV may survive infection during an epidemic.
This study further highlights the UK red squirrel – gray squirrel system as a classic example
of a native species population decline strongly facilitated by infectious disease introduced by a
non-native species. It is therefore paramount that disease prevention and control measures are
integral in attempts to conserve red squirrels in the United Kingdom.
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Affiliation(s)
- Julian Chantrey
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
| | - Timothy D Dale
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
| | - Jonathan M Read
- Institute of Infection and Global Health, University of Liverpool Leahurst Campus, Neston, CH64 7TE, U.K
| | - Steve White
- Lancashire Wildlife Trust, Seaforth Nature Reserve Liverpool, L21 1JD, U.K
| | - Fiona Whitfield
- Lancashire Wildlife Trust, Seaforth Nature Reserve Liverpool, L21 1JD, U.K
| | - David Jones
- Institute of Infection and Global Health, University of Liverpool Leahurst Campus, Neston, CH64 7TE, U.K
| | - Colin J McInnes
- Moredun Institute, Pentlands Science Park Bush Loan, Penicuik, Midlothian, EH26 0PZ, U.K
| | - Michael Begon
- Institute of Integrative Biology, University of Liverpool Biosciences Building, Crown Street, Liverpool, L69 7ZB, U.K
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22
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Collins LM, Warnock ND, Tosh DG, McInnes C, Everest D, Montgomery WI, Scantlebury M, Marks N, Dick JTA, Reid N. Squirrelpox virus: assessing prevalence, transmission and environmental degradation. PLoS One 2014; 9:e89521. [PMID: 24586845 PMCID: PMC3931809 DOI: 10.1371/journal.pone.0089521] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/21/2014] [Indexed: 11/19/2022] Open
Abstract
Red squirrels (Sciurus vulgaris) declined in Great Britain and Ireland during the last century, due to habitat loss and the introduction of grey squirrels (Sciurus carolinensis), which competitively exclude the red squirrel and act as a reservoir for squirrelpox virus (SQPV). The disease is generally fatal to red squirrels and their ecological replacement by grey squirrels is up to 25 times faster where the virus is present. We aimed to determine: (1) the seropositivity and prevalence of SQPV DNA in the invasive and native species at a regional scale; (2) possible SQPV transmission routes; and, (3) virus degradation rates under differing environmental conditions. Grey (n = 208) and red (n = 40) squirrel blood and tissues were sampled. Enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qPCR) techniques established seropositivity and viral DNA presence, respectively. Overall 8% of squirrels sampled (both species combined) had evidence of SQPV DNA in their tissues and 22% were in possession of antibodies. SQPV prevalence in sampled red squirrels was 2.5%. Viral loads were typically low in grey squirrels by comparison to red squirrels. There was a trend for a greater number of positive samples in spring and summer than in winter. Possible transmission routes were identified through the presence of viral DNA in faeces (red squirrels only), urine and ectoparasites (both species). Virus degradation analyses suggested that, after 30 days of exposure to six combinations of environments, there were more intact virus particles in scabs kept in warm (25°C) and dry conditions than in cooler (5 and 15°C) or wet conditions. We conclude that SQPV is present at low prevalence in invasive grey squirrel populations with a lower prevalence in native red squirrels. Virus transmission could occur through urine especially during warm dry summer conditions but, more notably, via ectoparasites, which are shared by both species.
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Affiliation(s)
- Lisa M. Collins
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- Institute for Global Food Security (IGFS), Queen’s University Belfast, Belfast, Northern Ireland
- School of Life Sciences, University of Lincoln, Lincolnshire, England
| | - Neil D. Warnock
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - David G. Tosh
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Colin McInnes
- Moredun Research Institute, Penicuik, Midlothian, Scotland
| | - David Everest
- Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone, Surrey, England
| | - W. Ian Montgomery
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Mike Scantlebury
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Nikki Marks
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | - Jaimie T. A. Dick
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- Institute for Global Food Security (IGFS), Queen’s University Belfast, Belfast, Northern Ireland
| | - Neil Reid
- Quercus, School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
- * E-mail:
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23
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Romeo C, Wauters LA, Ferrari N, Lanfranchi P, Martinoli A, Pisanu B, Preatoni DG, Saino N. Macroparasite fauna of alien grey squirrels (Sciurus carolinensis): composition, variability and implications for native species. PLoS One 2014; 9:e88002. [PMID: 24505348 PMCID: PMC3914897 DOI: 10.1371/journal.pone.0088002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 01/04/2014] [Indexed: 11/18/2022] Open
Abstract
Introduced hosts populations may benefit of an "enemy release" through impoverishment of parasite communities made of both few imported species and few acquired local ones. Moreover, closely related competing native hosts can be affected by acquiring introduced taxa (spillover) and by increased transmission risk of native parasites (spillback). We determined the macroparasite fauna of invasive grey squirrels (Sciurus carolinensis) in Italy to detect any diversity loss, introduction of novel parasites or acquisition of local ones, and analysed variation in parasite burdens to identify factors that may increase transmission risk for native red squirrels (S. vulgaris). Based on 277 grey squirrels sampled from 7 populations characterised by different time scales in introduction events, we identified 7 gastro-intestinal helminths and 4 parasite arthropods. Parasite richness is lower than in grey squirrel's native range and independent from introduction time lags. The most common parasites are Nearctic nematodes Strongyloides robustus (prevalence: 56.6%) and Trichostrongylus calcaratus (6.5%), red squirrel flea Ceratophyllus sciurorum (26.0%) and Holarctic sucking louse Neohaematopinus sciuri (17.7%). All other parasites are European or cosmopolitan species with prevalence below 5%. S. robustus abundance is positively affected by host density and body mass, C. sciurorum abundance increases with host density and varies with seasons. Overall, we show that grey squirrels in Italy may benefit of an enemy release, and both spillback and spillover processes towards native red squirrels may occur.
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Affiliation(s)
- Claudia Romeo
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
- * E-mail:
| | - Lucas A. Wauters
- Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Nicola Ferrari
- Department of Veterinary Sciences and Public Health, Università degli Studi di Milano, Milan, Italy
| | - Paolo Lanfranchi
- Department of Veterinary Sciences and Public Health, Università degli Studi di Milano, Milan, Italy
| | - Adriano Martinoli
- Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Benoît Pisanu
- Department of Ecology and Biodiversity Management, Muséum National d’Histoire Naturelle, Paris, France
| | - Damiano G. Preatoni
- Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, Varese, Italy
| | - Nicola Saino
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
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24
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McGowan NE, Marks NJ, McInnes CJ, Deane D, Maule AG, Scantlebury M. Effects of parasitism and morphology on squirrelpox virus seroprevalence in grey squirrels (Sciurus carolinensis). PLoS One 2014; 9:e83106. [PMID: 24416155 PMCID: PMC3885396 DOI: 10.1371/journal.pone.0083106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/31/2013] [Indexed: 01/08/2023] Open
Abstract
Invasive species have been cited as major causes of population extinctions in several animal and plant classes worldwide. The North American grey squirrel (Sciurus carolinensis) has a major detrimental effect on native red squirrel (Sciurus vulgaris) populations across Britain and Ireland, in part because it can be a reservoir host for the deadly squirrelpox virus (SQPV). Whilst various researchers have investigated the epizootiology of SQPV disease in grey squirrels and have modelled the consequent effects on red squirrel populations, less work has examined morphological and physiological characteristics that might make individual grey squirrels more susceptible to contracting SQPV. The current study investigated the putative relationships between morphology, parasitism, and SQPV exposure in grey squirrels. We found geographical, sex, and morphological differences in SQPV seroprevalence. In particular, larger animals, those with wide zygomatic arch widths (ZAW), males with large testes, and individuals with concurrent nematode and/or coccidial infections had an increased seroprevalence of SQPV. In addition, males with larger spleens, particularly those with narrow ZAW, were more likely to be exposed to SQPV. Overall these results show that there is variation in SQPV seroprevalence in grey squirrels and that, consequently, certain individual, or populations of, grey squirrels might be more responsible for transmitting SQPV to native red squirrel populations.
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Affiliation(s)
- Natasha E. McGowan
- School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Nikki J. Marks
- School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Colin J. McInnes
- Vaccines and Diagnostics, Moredun Research Institute, Edinburgh, United Kingdom
| | - David Deane
- Vaccines and Diagnostics, Moredun Research Institute, Edinburgh, United Kingdom
| | - Aaron G. Maule
- School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom
| | - Michael Scantlebury
- School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom
- * E-mail:
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25
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Squirrelpox Virus in Red Squirrels (Sciurus vulgaris) in the Republic of Ireland. J Wildl Dis 2013; 49:1070-3. [DOI: 10.7589/2013-04-086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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