A golden cage for the European red squirrel in Italy? Proposal for a targeted control of the grey squirrel

The Eurasian Red Squirrel (Sciurus vulgaris) is under threat from the invasive North American eastern Grey Squirrel (Sciurus carolinensis) with 80% of the remaining red squirrel populations in the British Isles found in Scotland. In this study we develop a spatially explicit mathematical model of the red and grey squirrel system and use it to assess the population viability of red squirrels across Scotland. In particular, we aim to identify existing forests – natural strongholds for red squirrels – that can successfully support red squirrels under UK Forestry Standard management and protect them from potential disease-mediated competition from grey squirrels. Our model results indicate that if current levels of grey squirrel control, which restrict or reduce the distribution of grey squirrels, are continued then there will be large expanses of forests in northern Scotland that support viable red squirrel populations. Model results that represent (hypothetical) scenarios where grey squirrel control no longer occurred indicated that grey squirrel range expansion and the process of red squirrel replacement would be slow. Model results for an assumed worst-case scenario where grey squirrels have expanded to all regions in Scotland identified forest regions – denoted natural strongholds – that could currently support red squirrels under UK Forestry Standard management practice. The results will be used to inform forest management policy and support a strategic review of red squirrel management by land management agencies and other stakeholders.

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Habitat mediates coevolved but not novel species interactions

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.2338 ◽

2022 ◽

Vol 289 (1966) ◽

Author(s):

Joshua P. Twining ◽

Chris Sutherland ◽

Neil Reid ◽

David G. Tosh

Keyword(s):

Species Interactions ◽

Prey Species ◽

Positive Influence ◽

Habitat Modification ◽

Red Squirrel ◽

Pine Marten ◽

Grey Squirrel ◽

Landscape Modification ◽

Anthropogenic Habitat ◽

Invasive Prey

Ongoing recovery of native predators has the potential to alter species interactions, with community and ecosystem wide implications. We estimated the co-occurrence of three species of conservation and management interest from a multi-species citizen science camera trap survey. We demonstrate fundamental differences in novel and coevolved predator–prey interactions that are mediated by habitat. Specifically, we demonstrate that anthropogenic habitat modification had no influence on the expansion of the recovering native pine marten in Ireland, nor does it affect the predator's suppressive influence on an invasive prey species, the grey squirrel. By contrast, the direction of the interaction between the pine marten and a native prey species, the red squirrel, is dependent on habitat. Pine martens had a positive influence on red squirrel occurrence at a landscape scale, especially in native broadleaf woodlands. However, in areas dominated by non-native conifer plantations, the pine marten reduced red squirrel occurrence. These findings suggest that following the recovery of a native predator, the benefits of competitive release are spatially structured and habitat-specific. The potential for past and future landscape modification to alter established interactions between predators and prey has global implications in the context of the ongoing recovery of predator populations in human-modified landscapes.

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Native and invasive squirrels show different behavioural responses to scent of a shared native predator

Royal Society Open Science ◽

10.1098/rsos.191841 ◽

2020 ◽

Vol 7 (2) ◽

pp. 191841 ◽

Cited By ~ 3

Author(s):

Joshua P. Twining ◽

W. Ian Montgomery ◽

Lily Price ◽

Hansjoerg P. Kunc ◽

David G. Tosh

Keyword(s):

Species Interactions ◽

Native Species ◽

Prey Species ◽

Red Squirrel ◽

Pine Marten ◽

Grey Squirrel ◽

Red Squirrels ◽

Behavioural Responses ◽

Grey Squirrels ◽

Native Predator

Invasive species pose a serious threat to native species. In Europe, invasive grey squirrels ( Sciurus carolinensis ) have replaced native red squirrels ( Sciurus vulgaris ) in locations across Britain, Ireland and Italy. The European pine marten ( Martes martes ) can reverse the replacement of red squirrels by grey squirrels, but the underlying mechanism of how pine martens suppress grey squirrels is little understood. Research suggests the reversal process is driven by direct predation, but why the native red squirrel may be less susceptible than the invasive grey squirrel to predation by a commonly shared native predator, is unknown. A behavioural difference may exist with the native sciurid being more effective at avoiding predation by the pine marten with which they have a shared evolutionary history. In mammals, olfactory cues are used by prey species to avoid predators. To test whether anti-predator responses differ between the native red squirrel and the invasive grey squirrel, we exposed both species to scent cues of a shared native predator and quantified the responses of the two squirrel species. Red squirrels responded to pine marten scent by avoiding the feeder, increasing their vigilance and decreasing their feeding activity. By contrast, grey squirrels did not show any anti-predator behaviours in response to the scent of pine marten. Thus, differences in behavioural responses to a shared native predator may assist in explaining differing outcomes of species interactions between native and invasive prey species depending on the presence, abundance and exposure to native predators.

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Imagining Rabbits and Squirrels in the English Countryside

Society and Animals ◽

10.1163/156853001753639260 ◽

2001 ◽

Vol 9 (2) ◽

pp. 163-175 ◽

Cited By ~ 1

Author(s):

Hilda Kean

Keyword(s):

Red Squirrel ◽

Way Of Life ◽

Grey Squirrel ◽

Red Squirrels ◽

The Past ◽

Country Life ◽

Post War

AbstractDrawing on contemporary coverage, particularly in The Field and Country Life, this article considers the construction of rabbits and squirrels as images of the past in England. By the 1930s, the red squirrel had become increasingly rare in the English countryside. Particularly in towns and suburbs, the population of the grey squirrel was growing rapidly. Those who saw themselves as the custodians of the countryside depicted the grey squirrel as a foreign force inimical to a mythical English way of life as epitomized by the red squirrel. In the post war period, the debate resurfaced about the nature of the countryside and who had a right to defend it. The focus then was upon the spread of myxomatosis from France, which was depicted as a foreign disease. Wild rabbits, who died in the thousands from this infection, became appropriated, as red squirrels before them, as symbols of a lyrical and ordered past in the countryside.

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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 ◽

10.1007/s00436-015-4466-3 ◽

2015 ◽

Vol 114 (7) ◽

pp. 2621-2628 ◽

Cited By ~ 17

Author(s):

Claudia Romeo ◽

Nicola Ferrari ◽

Paolo Lanfranchi ◽

Nicola Saino ◽

Francesca Santicchia ◽

...

Keyword(s):

Sciurus Carolinensis ◽

Red Squirrel ◽

Helminth Community ◽

Sciurus Vulgaris ◽

Grey Squirrel

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Epidemiology of squirrelpox virus in grey squirrels in the UK

Epidemiology and Infection ◽

10.1017/s0950268810000816 ◽

2010 ◽

Vol 138 (7) ◽

pp. 941-950 ◽

Cited By ~ 26

Author(s):

C. M. BRUEMMER ◽

S. P. RUSHTON ◽

J. GURNELL ◽

P. W. W. LURZ ◽

P. NETTLETON ◽

...

Keyword(s):

Disease Transmission ◽

Structural Equation ◽

Reservoir Host ◽

Red Squirrel ◽

Grey Squirrel ◽

Management Options ◽

Contact Points ◽

Squirrelpox Virus ◽

The Uk ◽

Grey Squirrels

SUMMARYThe dramatic decline of the native red squirrel in the UK has been attributed to both direct and disease-mediated competition with the grey squirrel where the competitor acts as a reservoir host of squirrelpox virus (SQPV). SQPV is threatening red squirrel conservation efforts, yet little is known about its epidemiology. We analysed seroprevalence of antibody against SQPV in grey squirrels from northern England and the Scottish Borders in relation to season, weather, sex, and body weight using Generalized Linear Models in conjunction with Structural Equation Modelling. Results indicated a heterogeneous prevalence pattern which is male-biased, increases with weight and varies seasonally. Seroprevalence rose during the autumn and peaked in spring. Weather parameters had an indirect effect on SQPV antibody status. Our findings point towards a direct disease transmission route, which includes environmental contamination. Red squirrel conservation management options should therefore seek to minimize squirrel contact points.

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