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John Gurnell - One of the best experts on this subject based on the ideXlab platform.
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poxviral disease in red Squirrels sciurus vulgaris in the uk spatial and temporal trends of an emerging threat
Ecohealth, 2008Co-Authors: A W Sainsbury, John Gurnell, Colin Mcinnes, Robert Deaville, Becki Lawson, W A Cooley, Stephan S J Farelly, Michael J Stack, Paul Duff, P H RussellAbstract:The Squirrel poxvirus (SQPV) is the probable mediator of apparent competition between the introduced invading gray Squirrel (Sciurus carolinensis) and the red Squirrel (Sciurus vulgaris) in the UK, and modeling studies have shown that this viral disease has had a significant impact on the decline of the red Squirrel in the UK. However, given our limited understanding of the epidemiology of the disease, and more generally the effects of invasive species on parasite ecology, there is a need to investigate the transmission dynamics and the relative pathogenicity of the virus between species. We aimed to increase our knowledge of these processes through an empirical study in which we: (i) used pathological signs and transmission electron microscopy (TEM) to diagnose SQPV disease in red Squirrels found dead during scanning surveillance between 1993 and 2005; (ii) detected antibody to SQPV using an enzyme-linked immunosorbent assay (ELISA) in the same animals; and (iii) mapped cases of the disease, and the gray Squirrel distribution, using a geographical information system. We analyzed the distribution of cases of SQPV disease according to woodland type, a measure of Squirrel density. SQPV disease occurred only in areas of England also inhabited by seropositive gray Squirrels, and as the geographical range of gray Squirrels expanded, SQPV disease occurred in these new gray Squirrel habitats, supporting a role for the gray Squirrel as a reservoir host of the virus. There was a delay between the establishment of invading gray Squirrels and cases of the disease in red Squirrels which implies gray Squirrels must reach a threshold number or density before the virus is transmitted to red Squirrels. The spatial and temporal trend in SQPV disease outbreaks suggested that SQPV disease will have a significant effect on Scottish populations of red Squirrels within 25 years. The even spread of cases of disease across months suggested a direct rather than vector-borne transmission route is more likely. Eight juvenile and sub-adult free-living red Squirrels apparently survived exposure to SQPV by mounting an immune response, the first evidence of immunity to SQPV in free-living red Squirrels, which possibly suggests a changing host-parasite relationship and that the use of a vaccine may be an effective management tool to protect remnant red Squirrel populations.
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disease threats posed by alien species the role of a poxvirus in the decline of the native red Squirrel in britain
Epidemiology and Infection, 2006Co-Authors: S P Rushton, Peter W. W. Lurz, John Gurnell, P. F. Nettleton, Mark D. F. Shirley, C. Bruemmer, A W SainsburyAbstract:Red Squirrels are declining in the United Kingdom. Competition from, and Squirrel poxvirus (SQPV) disease carried by, grey Squirrels are assumed to be determining the decline. We analyse the incidence of disease and changes in distribution of the two species in Cumbria, from 1993 to 2003 and compare these to the predictions of an individual-based (IB) spatially explicit disease model simulating the dynamics of both Squirrel species and SQPV in the landscape. Grey Squirrels increased whilst red Squirrels declined over 10 years. The incidence of disease in red Squirrels was related to the time since grey Squirrels arrived in the landscape. Analysis of rates of decline in red Squirrel populations in other areas showed that declines are 17–25 times higher in regions where SQPV is present in grey Squirrel populations than in those where it is not. The IB model predicted spatial overlap of 3–4 years between the species that was also observed in the field. The model predictions matched the observed data best when contact rates and rates of infection between the two species were low. The model predicted that a grey Squirrel population control of >60% effective kill was needed to stop the decline in red Squirrel populations in Cumbria.
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Squirrel poxvirus: Landscape scale strategies for managing disease threat
Biological Conservation, 2006Co-Authors: John Gurnell, Peter W. W. Lurz, Stephen P. Rushton, Anthony W. Sainsbury, P. F. Nettleton, Mark D. F. Shirley, C. Bruemmer, N. GeddesAbstract:Abstract Squirrel poxvirus (SQPV) is a well-documented example of pathogen-mediated competition between an invasive species, the grey Squirrel ( Sciurus carolinensis ), and a native species, the Eurasian red Squirrel ( Sciurus vulgaris ). SQPV causes disease with high mortality in red Squirrels but appears non-pathogenic in grey Squirrels. Not all populations of introduced grey Squirrels carry the virus, notably those in Scotland and Italy, and the rate of red Squirrel replacement by grey Squirrels is some twenty times faster in those areas where grey Squirrels carry the virus. Here we develop strategies to manage the SQPV disease threat to red Squirrels by reference to the largest, designated red Squirrel refuge site in England, Kielder Forest (50 000 ha). Using modelling techniques, we identify four main corridors within the buffer zone by which grey Squirrels will reach Kielder, initially within two years and in large numbers within 10 years. Assuming that greys will not settle within Kielder because of the unfavourable nature of the spruce habitat, we predict that SQPV disease will burn out at the edges of the forest, although many red Squirrels will die. This burn-out is unlikely to be the scenario in other refuge areas where the habitat is more favourable to greys. We conclude that the conservation of red Squirrels will depend on minimising contact between red and grey Squirrel populations, and we advocate monitoring grey Squirrels in corridors within buffer zones around refuge areas, and removing them when detected.
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Alien species and interspecific competition: effects of introduced eastern grey Squirrels on red Squirrel population dynamics
Journal of Animal Ecology, 2004Co-Authors: John Gurnell, Luc A Wauters, Peter W. W. Lurz, Guido TosiAbstract:Summary 1. Throughout much of Britain, Ireland and north Italy, red Squirrels ( Sciurus vulgaris L.) have been replaced by alien grey Squirrels ( S. carolinensis Gmelin) introduced from North America. We have studied Squirrels in two mixed woodlands in north Italy and two conifer forests in north England. In each country, one site was occupied by red Squirrels and one site by both species. 2. We have previously considered interference competition and exploitation competition for food and space between red and grey Squirrels and have showed that grey Squirrels caused reduced body growth in juvenile and subadult red Squirrels, and compete for tree seeds cached by adult red Squirrels in spring. Here we report on the effects of grey Squirrels on three fitness components in red Squirrels that have consequence at the population level: fecundity, residency and recruitment. 3. Litter production peaked in the spring and summer, but fewer females bred in the summer with grey Squirrels present. In addition, fewer individual red Squirrel females produced two litters per year in the sites with grey Squirrels. Moreover, red Squirrel recruitment rate and, in the mixed broadleaf sites, red Squirrel juvenile residency, decreased with increasing grey Squirrel density. 4. Fecundity of individual female red Squirrels was lower in red‐grey than in red-only sites because they had a lower body mass in sites with grey Squirrels. 5. Overall, there was no significant effect of grey Squirrels on residency of adult red Squirrels or on population turnover rate. However, the presence of grey Squirrels resulted in a reduction in red Squirrel fitness which was evident by lower population summer breeding and a lower recruitment. Over time, this will result in a decline in population size and eventually population extinction.
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conserving red Squirrels sciurus vulgaris mapping and forecasting habitat suitability using a geographic information systems approach
Biological Conservation, 2002Co-Authors: John Gurnell, Peter W. W. Lurz, Mark D. F. Shirley, Michael J Clark, S P RushtonAbstract:A model of habitat suitability linked to a Geographic Information System was developed for the red Squirrel (Sciurus vulgaris) in 2800 ha of Thetford Forest, East England, to assess red Squirrel population numbers in relation to forest management. We defined each forest sub-compartment or parcel of land in terms of its tree species and age between 1995 and 2015, and categorised each parcel of land as low, moderate or high red Squirrel suitability. Resident Squirrels may live in more than one habitat patch providing the distance between patches is within the foraging range of the animals and the land between the patches does not act as a barrier to foraging movements. Moreover, Squirrels require a minimum area (home range area) of suitable habitat that will provide them with sufficient food resources. To examine these two factors, we explored 120 different model scenarios using three different distances to link patches together and four different sized minimum areas, termed minimum linked areas (MLA), that would hold resident red Squirrels, at five year intervals between 1995 and 2015. As an overall measure of suitability, we summed all the MLAs in the reserve for high plus moderate suitability, which we have called the total linked area (TLA), and forecast how this may change in the future. We show that TLA will increase from 39% in 1995 to 67% of the study area by 2015, demonstrating that the reserve will get better for red Squirrels over this time. We also demonstrate how changes in forest management would further increase TLA to 82% by 2015. Our results demonstrate how a habitat suitability model operating at the scale of an individual forest, coupled with a GIS and based on an understanding of the species' ecology, provides an objective way of assessing the impact of forest management prescriptions on red Squirrel populations.
Peter W. W. Lurz - One of the best experts on this subject based on the ideXlab platform.
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integrating red Squirrel sciurus vulgaris habitat requirements with the management of pathogenic tree disease in commercial forests in the uk
Forest Ecology and Management, 2012Co-Authors: Craig M. Shuttleworth, Peter W. W. Lurz, Neville Geddes, John BrowneAbstract:Abstract The native red Squirrel is being replaced by the introduced North American eastern grey Squirrel in the UK. Here, Sitka spruce dominated plantations containing a larch and pine element offer the best long-term opportunity to conserve the red Squirrel because they can sustain populations in a forest environment where the competitive advantage of the grey Squirrel is reduced. Forest habitat management in designated stronghold areas in England and Scotland is therefore a key strategy for red Squirrel conservation. However, the threat of pathogenic tree disease is already leading to changes in forest composition through modified thinning and planting regimes. This has the potential of not only altering habitat suitability for red Squirrels but also the competitive ability of grey Squirrels. For example, Phytophthora ramorum can severely affect Japanese larch, whilst other common crop species such as Corsican pine, Scots pine and lodgepole pine are all vulnerable to Red Band Needle Blight (Dothistroma septosporum); factors driving significant changes in future forest composition. In this paper we wish to highlight the serious impact of these diseases on established red Squirrel management options. We examine proactive and reactive management in three case studies which are attempting to integrate red Squirrel habitat requirements into evolving tree disease management protocols. We recommend specific tree species that are both less susceptible to infections and offer potential alternative seed sources for red Squirrels, whilst stressing the need for research into grey Squirrel exploitation of such crops. We also highlight how the presence of grey Squirrels is limiting the use of hazel and other broadleaved species in this context. Finally, a flexible red Squirrel management protocol is presented to assist forest managers to integrate red Squirrel conservation with the threat posed by Red Band Needle Blight and P. ramorum.
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disease threats posed by alien species the role of a poxvirus in the decline of the native red Squirrel in britain
Epidemiology and Infection, 2006Co-Authors: S P Rushton, Peter W. W. Lurz, John Gurnell, P. F. Nettleton, Mark D. F. Shirley, C. Bruemmer, A W SainsburyAbstract:Red Squirrels are declining in the United Kingdom. Competition from, and Squirrel poxvirus (SQPV) disease carried by, grey Squirrels are assumed to be determining the decline. We analyse the incidence of disease and changes in distribution of the two species in Cumbria, from 1993 to 2003 and compare these to the predictions of an individual-based (IB) spatially explicit disease model simulating the dynamics of both Squirrel species and SQPV in the landscape. Grey Squirrels increased whilst red Squirrels declined over 10 years. The incidence of disease in red Squirrels was related to the time since grey Squirrels arrived in the landscape. Analysis of rates of decline in red Squirrel populations in other areas showed that declines are 17–25 times higher in regions where SQPV is present in grey Squirrel populations than in those where it is not. The IB model predicted spatial overlap of 3–4 years between the species that was also observed in the field. The model predictions matched the observed data best when contact rates and rates of infection between the two species were low. The model predicted that a grey Squirrel population control of >60% effective kill was needed to stop the decline in red Squirrel populations in Cumbria.
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Squirrel poxvirus: Landscape scale strategies for managing disease threat
Biological Conservation, 2006Co-Authors: John Gurnell, Peter W. W. Lurz, Stephen P. Rushton, Anthony W. Sainsbury, P. F. Nettleton, Mark D. F. Shirley, C. Bruemmer, N. GeddesAbstract:Abstract Squirrel poxvirus (SQPV) is a well-documented example of pathogen-mediated competition between an invasive species, the grey Squirrel ( Sciurus carolinensis ), and a native species, the Eurasian red Squirrel ( Sciurus vulgaris ). SQPV causes disease with high mortality in red Squirrels but appears non-pathogenic in grey Squirrels. Not all populations of introduced grey Squirrels carry the virus, notably those in Scotland and Italy, and the rate of red Squirrel replacement by grey Squirrels is some twenty times faster in those areas where grey Squirrels carry the virus. Here we develop strategies to manage the SQPV disease threat to red Squirrels by reference to the largest, designated red Squirrel refuge site in England, Kielder Forest (50 000 ha). Using modelling techniques, we identify four main corridors within the buffer zone by which grey Squirrels will reach Kielder, initially within two years and in large numbers within 10 years. Assuming that greys will not settle within Kielder because of the unfavourable nature of the spruce habitat, we predict that SQPV disease will burn out at the edges of the forest, although many red Squirrels will die. This burn-out is unlikely to be the scenario in other refuge areas where the habitat is more favourable to greys. We conclude that the conservation of red Squirrels will depend on minimising contact between red and grey Squirrel populations, and we advocate monitoring grey Squirrels in corridors within buffer zones around refuge areas, and removing them when detected.
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Alien species and interspecific competition: effects of introduced eastern grey Squirrels on red Squirrel population dynamics
Journal of Animal Ecology, 2004Co-Authors: John Gurnell, Luc A Wauters, Peter W. W. Lurz, Guido TosiAbstract:Summary 1. Throughout much of Britain, Ireland and north Italy, red Squirrels ( Sciurus vulgaris L.) have been replaced by alien grey Squirrels ( S. carolinensis Gmelin) introduced from North America. We have studied Squirrels in two mixed woodlands in north Italy and two conifer forests in north England. In each country, one site was occupied by red Squirrels and one site by both species. 2. We have previously considered interference competition and exploitation competition for food and space between red and grey Squirrels and have showed that grey Squirrels caused reduced body growth in juvenile and subadult red Squirrels, and compete for tree seeds cached by adult red Squirrels in spring. Here we report on the effects of grey Squirrels on three fitness components in red Squirrels that have consequence at the population level: fecundity, residency and recruitment. 3. Litter production peaked in the spring and summer, but fewer females bred in the summer with grey Squirrels present. In addition, fewer individual red Squirrel females produced two litters per year in the sites with grey Squirrels. Moreover, red Squirrel recruitment rate and, in the mixed broadleaf sites, red Squirrel juvenile residency, decreased with increasing grey Squirrel density. 4. Fecundity of individual female red Squirrels was lower in red‐grey than in red-only sites because they had a lower body mass in sites with grey Squirrels. 5. Overall, there was no significant effect of grey Squirrels on residency of adult red Squirrels or on population turnover rate. However, the presence of grey Squirrels resulted in a reduction in red Squirrel fitness which was evident by lower population summer breeding and a lower recruitment. Over time, this will result in a decline in population size and eventually population extinction.
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conserving red Squirrels sciurus vulgaris mapping and forecasting habitat suitability using a geographic information systems approach
Biological Conservation, 2002Co-Authors: John Gurnell, Peter W. W. Lurz, Mark D. F. Shirley, Michael J Clark, S P RushtonAbstract:A model of habitat suitability linked to a Geographic Information System was developed for the red Squirrel (Sciurus vulgaris) in 2800 ha of Thetford Forest, East England, to assess red Squirrel population numbers in relation to forest management. We defined each forest sub-compartment or parcel of land in terms of its tree species and age between 1995 and 2015, and categorised each parcel of land as low, moderate or high red Squirrel suitability. Resident Squirrels may live in more than one habitat patch providing the distance between patches is within the foraging range of the animals and the land between the patches does not act as a barrier to foraging movements. Moreover, Squirrels require a minimum area (home range area) of suitable habitat that will provide them with sufficient food resources. To examine these two factors, we explored 120 different model scenarios using three different distances to link patches together and four different sized minimum areas, termed minimum linked areas (MLA), that would hold resident red Squirrels, at five year intervals between 1995 and 2015. As an overall measure of suitability, we summed all the MLAs in the reserve for high plus moderate suitability, which we have called the total linked area (TLA), and forecast how this may change in the future. We show that TLA will increase from 39% in 1995 to 67% of the study area by 2015, demonstrating that the reserve will get better for red Squirrels over this time. We also demonstrate how changes in forest management would further increase TLA to 82% by 2015. Our results demonstrate how a habitat suitability model operating at the scale of an individual forest, coupled with a GIS and based on an understanding of the species' ecology, provides an objective way of assessing the impact of forest management prescriptions on red Squirrel populations.
Craig M. Shuttleworth - One of the best experts on this subject based on the ideXlab platform.
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british red Squirrels remain the only known wild rodent host for leprosy bacilli
Frontiers in Veterinary Science, 2019Co-Authors: Annakatarina Schilling, Claudia Romeo, Nicola Ferrari, Benoit Pisanu, Maria Vittoria Mazzamuto, Rainer G. Ulrich, Charlotte Avanzi, Philippe Busso, Joyce Mcluckie, Craig M. ShuttleworthAbstract:Eurasian red Squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different Squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild Squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground Squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 Squirrel samples covering four species (96 Eurasian red Squirrels, 67 Eastern grey Squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas’s Squirrels (Callosciurus erythraeus)) from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red Squirrels.
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Table_1_British Red Squirrels Remain the Only Known Wild Rodent Host for Leprosy Bacilli.XLSX
2019Co-Authors: Annakatarina Schilling, Claudia Romeo, Nicola Ferrari, Benoit Pisanu, Maria Vittoria Mazzamuto, Rainer G. Ulrich, Charlotte Avanzi, Philippe Busso, Joyce Mcluckie, Craig M. ShuttleworthAbstract:Eurasian red Squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different Squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild Squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground Squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 Squirrel samples covering four species [96 Eurasian red Squirrels, 67 Eastern gray Squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas's Squirrels (Callosciurus erythraeus)] from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red Squirrels.
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Landscape scale impacts of culling upon a European grey Squirrel population: can trapping reduce population size and decrease the threat of Squirrelpox virus infection for the native red Squirrel?
Biological Invasions, 2014Co-Authors: Pia Schuchert, David J. Everest, Craig M. Shuttleworth, Colin J. Mcinnes, Steven P. RushtonAbstract:The control of grey Squirrels ( Sciurus carolinensis ) is widely undertaken as a conservation measure to protect red Squirrel ( Sciurus vulgaris ) populations in the UK. However, inconsistencies and omissions in data collection, as well as fluctuating financial resourcing of control efforts, have meant that it has to date proved difficult to quantify the impact of any regional control initiative upon populations. Here we have scrutinized a 13 years period (1998–2010) within an ongoing grey Squirrel control project that reflects the resource challenges typically faced by red Squirrel conservation programmes. We present evidence that despite variation in grey Squirrel control intensity, the abundance of grey Squirrels ultimately decreased significantly. Trapping success was significantly higher in spring and summer months and a greater abundance of grey Squirrels was found in deciduous woodland and hazel dominated scrub relative to other habitats; two findings that reinforce existing guidance within national control best practice. Grey Squirrels carry an infection that causes epidemic pathogenic disease if spread to the native red Squirrel. We observed that the proportion of seropositive grey Squirrels decreased constantly from 2003 to 2010 when only 4 % of sampled animals were seropositive. This discovery indicates that culling can in parallel remove both the competitive and disease threat posed to red by grey Squirrels. The historical paucity of scientific data on the effectiveness of grey Squirrel control as a tactic in UK red Squirrel conservation means that the findings of this study will significantly advance conservation best practice and inform the development of future national strategy.
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integrating red Squirrel sciurus vulgaris habitat requirements with the management of pathogenic tree disease in commercial forests in the uk
Forest Ecology and Management, 2012Co-Authors: Craig M. Shuttleworth, Peter W. W. Lurz, Neville Geddes, John BrowneAbstract:Abstract The native red Squirrel is being replaced by the introduced North American eastern grey Squirrel in the UK. Here, Sitka spruce dominated plantations containing a larch and pine element offer the best long-term opportunity to conserve the red Squirrel because they can sustain populations in a forest environment where the competitive advantage of the grey Squirrel is reduced. Forest habitat management in designated stronghold areas in England and Scotland is therefore a key strategy for red Squirrel conservation. However, the threat of pathogenic tree disease is already leading to changes in forest composition through modified thinning and planting regimes. This has the potential of not only altering habitat suitability for red Squirrels but also the competitive ability of grey Squirrels. For example, Phytophthora ramorum can severely affect Japanese larch, whilst other common crop species such as Corsican pine, Scots pine and lodgepole pine are all vulnerable to Red Band Needle Blight (Dothistroma septosporum); factors driving significant changes in future forest composition. In this paper we wish to highlight the serious impact of these diseases on established red Squirrel management options. We examine proactive and reactive management in three case studies which are attempting to integrate red Squirrel habitat requirements into evolving tree disease management protocols. We recommend specific tree species that are both less susceptible to infections and offer potential alternative seed sources for red Squirrels, whilst stressing the need for research into grey Squirrel exploitation of such crops. We also highlight how the presence of grey Squirrels is limiting the use of hazel and other broadleaved species in this context. Finally, a flexible red Squirrel management protocol is presented to assist forest managers to integrate red Squirrel conservation with the threat posed by Red Band Needle Blight and P. ramorum.
Lucas A. Wauters - One of the best experts on this subject based on the ideXlab platform.
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biodiversity threats from outside to inside effects of alien grey Squirrel sciurus carolinensis on helminth community of native red Squirrel sciurus vulgaris
Parasitology Research, 2015Co-Authors: Claudia Romeo, Adriano Martinoli, Nicola Ferrari, Francesca Santicchia, P Lanfranchi, Nicola Saino, Lucas A. WautersAbstract:Biological invasions are among the major causes of biodiversity loss worldwide, and parasites carried or acquired by invaders may represent an added threat to native species. We compared gastrointestinal helminth communities of native Eurasian red Squirrels (Sciurus vulgaris) in the presence and absence of introduced Eastern grey Squirrels (Sciurus carolinensis) to detect alterations induced by the alien species. In particular, we investigated whether spillover of a North American nematode Strongyloides robustus occurs and whether prevalence of a local parasite Trypanoxyuris sciuri in red Squirrels is affected by grey Squirrel presence. The probability of being infected by both parasites was significantly higher in areas co-inhabited by the alien species, where 61 % of examined red Squirrels (n = 49) were infected by S. robustus and 90 % by T. sciuri. Conversely, in red-only areas, the two parasites infected only 5 and 70 % of individuals (n = 60). Overall, our findings support the hypothesis that red Squirrels acquire S. robustus via spillover from the alien congener and suggest that invaders’ presence may also indirectly affect infection by local parasites through mechanisms diverse than spill-back and linked to the increased competitive pressure to which red Squirrels are subjected. These results indicate that the impact of grey Squirrel on red Squirrels may have been underestimated and highlight the importance of investigating variation in macroparasite communities of native species threatened by alien competitors.
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a grey future for europe sciurus carolinensis is replacing native red Squirrels in italy
Biological Invasions, 2014Co-Authors: Sandro Bertolino, Damiano Preatoni, Lucas A. Wauters, Nicola Cordero Di Montezemolo, Adriano MartinoliAbstract:Introduced mammals can cause extinction of native species due to replacement competition, disease, predation or hybridization. We studied the colonization of Piedmont (NW-Italy) by American grey Squirrel (Sciurus carolinensis) and its effect on the native red Squirrel (Sciurus vulgaris). Presence/absence data (2 × 2 km2), of both species were (re)constructed using questionnaires, literature, existing databases, unpublished information, and direct monitoring with hair-tubes. In 1970 red Squirrels were still widespread and greys were restricted to forests near the introduction site. By 1990, grey Squirrels had increased their range to 220 km2, which coincided with the disappearance of native Squirrels from 33 squares inside this range. The invasive species continued its spread occupying an area of 2,016 km2 in 2010; within this area red Squirrels went extinct in 88 squares. Overall, from 1970 to 2010 red Squirrel went extinct in 62 % of 2 × 2 km2 (ca. 1,689 km2), and were replaced by grey Squirrels. The spread of the alien species was slow in the first 20 years, but doubled in the successive two decades. Nevertheless spread was slower than in Ireland and England. Grey Squirrel adapt to climate and habitats in both North and South Europe, causing extinction of the native red Squirrel. A EU LIFE co-funded project with the aim to control the grey Squirrel in North Italy and recent trade-restrictions and trade-ban are a first step in reducing the risk of grey Squirrels invading other countries, but their effectiveness will have to be evaluated.
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scale dependent environmental variables affecting red Squirrel sciurus vulgaris meridionalis distribution
Italian Journal of Zoology, 2010Co-Authors: P.c. Rima, M. Cagnin, Gaetano Aloise, Damiano Preatoni, Lucas A. WautersAbstract:We investigated the effects of habitat fragmentation on the endemic subspecies of red Squirrel Sciurus vulgaris meridionalis in the Pollino National Park, Calabria, Southern Italy. Presence/absence of Squirrels was monitored using drey (nest) counts in 51 1‐ha census plots. Squirrel dreys were found in 16 plots (31%). Patch size was not correlated to Squirrel presence. Squirrels were found in patches ranging from 3.19 to 6051 ha. Small‐scale forest structure significantly affected the probability of occurrence. The proportion of conifers and average tree height positively predict Squirrel presence; furthermore, nest density was positively correlated with high tree species diversity and the proportion of deciduous oaks (Quercus cerris, Q. ilex). Also at the home‐range scale the proportion of conifer forest and oak‐dominated deciduous forests positively predicted Squirrel presence (200–300 m radius). At the even larger scale, corresponding with potential dispersal distances (3000 m radius), landscape parame...
Claudia Romeo - One of the best experts on this subject based on the ideXlab platform.
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british red Squirrels remain the only known wild rodent host for leprosy bacilli
Frontiers in Veterinary Science, 2019Co-Authors: Annakatarina Schilling, Claudia Romeo, Nicola Ferrari, Benoit Pisanu, Maria Vittoria Mazzamuto, Rainer G. Ulrich, Charlotte Avanzi, Philippe Busso, Joyce Mcluckie, Craig M. ShuttleworthAbstract:Eurasian red Squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different Squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild Squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground Squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 Squirrel samples covering four species (96 Eurasian red Squirrels, 67 Eastern grey Squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas’s Squirrels (Callosciurus erythraeus)) from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red Squirrels.
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Table_1_British Red Squirrels Remain the Only Known Wild Rodent Host for Leprosy Bacilli.XLSX
2019Co-Authors: Annakatarina Schilling, Claudia Romeo, Nicola Ferrari, Benoit Pisanu, Maria Vittoria Mazzamuto, Rainer G. Ulrich, Charlotte Avanzi, Philippe Busso, Joyce Mcluckie, Craig M. ShuttleworthAbstract:Eurasian red Squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different Squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild Squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground Squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 Squirrel samples covering four species [96 Eurasian red Squirrels, 67 Eastern gray Squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas's Squirrels (Callosciurus erythraeus)] from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red Squirrels.
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biodiversity threats from outside to inside effects of alien grey Squirrel sciurus carolinensis on helminth community of native red Squirrel sciurus vulgaris
Parasitology Research, 2015Co-Authors: Claudia Romeo, Adriano Martinoli, Nicola Ferrari, Francesca Santicchia, P Lanfranchi, Nicola Saino, Lucas A. WautersAbstract:Biological invasions are among the major causes of biodiversity loss worldwide, and parasites carried or acquired by invaders may represent an added threat to native species. We compared gastrointestinal helminth communities of native Eurasian red Squirrels (Sciurus vulgaris) in the presence and absence of introduced Eastern grey Squirrels (Sciurus carolinensis) to detect alterations induced by the alien species. In particular, we investigated whether spillover of a North American nematode Strongyloides robustus occurs and whether prevalence of a local parasite Trypanoxyuris sciuri in red Squirrels is affected by grey Squirrel presence. The probability of being infected by both parasites was significantly higher in areas co-inhabited by the alien species, where 61 % of examined red Squirrels (n = 49) were infected by S. robustus and 90 % by T. sciuri. Conversely, in red-only areas, the two parasites infected only 5 and 70 % of individuals (n = 60). Overall, our findings support the hypothesis that red Squirrels acquire S. robustus via spillover from the alien congener and suggest that invaders’ presence may also indirectly affect infection by local parasites through mechanisms diverse than spill-back and linked to the increased competitive pressure to which red Squirrels are subjected. These results indicate that the impact of grey Squirrel on red Squirrels may have been underestimated and highlight the importance of investigating variation in macroparasite communities of native species threatened by alien competitors.
