title: Invading and expanding: range dynamics and ecological consequences of the greater white-toothed shrew (Crocidura russula) invasion in Ireland.
abstract: Establishing how invasive species impact upon pre-existing species is a fundamental question in ecology and conservation biology. The greater white-toothed shrew (Crocidura russula) is an invasive species in Ireland that was first recorded in 2007 and which, according to initial data, may be limiting the abundance/distribution of the pygmy shrew (Sorex minutus), previously Ireland's only shrew species. Because of these concerns, we undertook an intensive live-trapping survey (and used other data from live-trapping, sightings and bird of prey pellets/nest inspections collected between 2006 and 2013) to model the distribution and expansion of C. russula in Ireland and its impacts on Ireland's small mammal community. The main distribution range of C. russula was found to be approximately 7,600 km2 in 2013, with established outlier populations suggesting that the species is dispersing with human assistance within the island. The species is expanding rapidly for a small mammal, with a radial expansion rate of 5.5 km/yr overall (2008-2013), and independent estimates from live-trapping in 2012-2013 showing rates of 2.4-14.1 km/yr, 0.5-7.1 km/yr and 0-5.6 km/yr depending on the landscape features present. S. minutus is negatively associated with C. russula. S. minutus is completely absent at sites where C. russula is established and is only present at sites at the edge of and beyond the invasion range of C. russula. The speed of this invasion and the homogenous nature of the Irish landscape may mean that S. minutus has not had sufficient time to adapt to the sudden appearance of C. russula. This may mean the continued decline/disappearance of S. minutus as C. russula spreads throughout the island.
authors: School of Biology and Environmental Science, University College Dublin, Dublin, Ireland.
authors: Allan D
authors: AD
authors: McDevitt
authors: School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland; Quercus, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland.
authors: W Ian
authors: WI
authors: Montgomery
authors: Quercus, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland.
authors: David G
authors: DG
authors: Tosh
authors: Birdwatch Ireland, Kilcoole, Co. Wicklow, Ireland.
authors: John
authors: J
authors: Lusby
authors: Quercus, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland.
authors: Neil
authors: N
authors: Reid
authors: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, United States of America; Department of Biology, University of Oulu, Oulu, Finland.
authors: Thomas A
authors: TA
authors: White
authors: Deele College, Raphoe, Co. Donegal, Ireland.
authors: C Damien
authors: CD
authors: McDevitt
authors: School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
authors: John
authors: J
authors: O'Halloran
authors: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, United States of America.
authors: Jeremy B
authors: JB
authors: Searle
authors: School of Biology and Environmental Science, University College Dublin, Dublin, Ireland.
authors: Jon M
authors: JM
authors: Yearsley
mesh_terms: D000818:Animals; D004463:Ecology; D017753:Ecosystem; D006801:Humans; D058865:Introduced Species / Q000706:statistics & numerical data*; D007494:Ireland; D012788:Shrews / Q000145:classification* / Q000254:growth & development*; D013045:Species Specificity