An experimental release of red squirrels into conifer woodland occupied by grey squirrels in southern Britain: implications for conservation of red squirrels. A critical look at conserving the British red squirrel Sciurus vulgaris. The effects of food availability and winter weather on the dynamics of a grey squirrel population in southern England. Blackwell Scientific Publications, Oxford, UK. In Handbook of British Mammals, 3rd edition, pp. Squirrel numbers and the abundance of tree seeds. A review of methods for the assessment of prediction errors in conservation presence/absence models. Special Publication Virginia Museum of Natural History 6, Martinsville, VA, USA.įielding, A.H. In Ecology and Evolutionary Biology of Tree Squirrels. Bark removal damage by grey squirrels in Britain – a review. Annali della Facolta di Scienze Agrarie della Universita di Torino 14: 307–331.ĭagnall, J., Pepper, H. Note sulla presenza dello scoiattolo grigio ( Sciurus carolinensis Gmelin) in Piemonte. Special Publication Virginia Museum of Natural History 6, Martinsville, VA, USA.Ĭurrado, I., Scaramozzino, P.L. In Ecology and Evolutionary Biology of Three Squirrels. The gray squirrel ( Sciurus carolinensis Gmelin) in Italy: a potential problem for the entire European continent. Do lemmings commit suicide? Oxford University Press, Oxford, UK.Ĭurrado, I. Occupancy of isolated woodlots by the red squirrel Sciurus vulgaris L. Vertebrate fauna introduced in Piedmont (Osteichthyes, Amphibia, Reptilia, Aves, Mammalia). Acceptance criteria for using individual-based models to make management decisions. The role of habitat and mink predation in determining the status and distribution of water voles in England. Habitat selection in the Eurasian red squirrel, Sciurus vulgaris, in relation to forest fragmentation. Effects of habitat framentation on birds and mammals in landscapes with different proportions of suitable habitat: a review. If allowed to spread, grey squirrels have the potential of becoming a European forest pest species and are likely to replace the native red squirrel in large parts of its range.Īdrén, H. The case of the grey squirrel highlights the problems of implementing conservation conventions and the resulting conflicts between wildlife management, public perception and local political support and the narrow time frame that is available to control alien species effectively before it is too late. In both cases they could disperse along existing continuous woodland corridors into France between 2039–2048. We also present a ‘worst case’ scenario in which grey squirrels experience improved reproductive success due to the availability of high quality habitats beyond the Po plain. The structure and composition of woodland habitats around the introduction site suggested that initial grey squirrel expansion would have been slow and subject to emigration rates from the available habitat blocks.Ī comparison of the 1996 survey results with model predictions indicated that a mean litter size of three young gave the best fit with the observed distribution and we use this to predict future grey squirrel spread. The analysis indicated that reproductive output was the most important factor determining total population size present in Piedmont. We extended a previous approach employing a sensitivity analysis where life history and other demographic inputs are generated using Latin Hypercube Sampling from the known ranges of each input parameter, and applied it to Italy using field data collected in Piedmont. Spatially explicit population dynamics models have been successfully used to predict the spread of grey squirrels in East Anglia, England. In parallel to what has been observed in Britain and Ireland, grey squirrels replace the native red squirrel (S. vulgaris) and damage poplar ( Populus) plantations through bark-stripping. They have since spread across the Po-plain covering an area of approximately 450 km 2 and continue to expand their range. There is growing concern about the spread of the North American grey squirrel ( Sciurus carolinensis) in northern Italy which were introduced into Piedmont in 1948.
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