Range expansion of the greater white-toothed shrewCrocidura russula in Switzerland results in local extinction of the bicoloured white-toothed shrewC. leucodon

Abstract

2002. Range expansion of the greater white-toothed shrew Crocidura russula in Switzerland results in local extinction of the bicoloured white-toothed shrew C. leucodon. Acta Theriologica 47: 15-24.The distribution limits of Crocidura russula (Hermann, 1780) and C. leucodon (Hermann, 1780) were investigated during an interval of 25 years in the bottom of the Rhone valley above Lake Geneva, Switzerland (total data set: 105 spatio-temporal occurrences, 1137 shrews). In 1975, the contact zone between the two species was situated in the region of Martigny. In 1999/2000, new sampling revealed three results:(1) The contact zone showed an upward shift of about 25 km. (2) In the expanded range of C. russula, the resident species has totally disappeared (confirmed by owl pellets analysis). (3) This demonstrates a dominance of C. russula over C. leucodon. Three hypotheses which may explain the range expansion of C. russula were evaluated:(1) habitat modification favouring linear dispersal due to the construction of a highway;(2) temporal event favoured by climate fluctuations, or (3) ongoing postglacial colonisation of Europe. Hypothesis 1 was rejected, because the progression of the shrews anticipated the construction. Hypothesis 3 received only weak support because range limits of C. russula in the region of Nice have been stable for thousands of years. Therefore hypothesis 2, admitting that ongoing climate change has facilitated range expansion, is the most probable.

Evolutionary responses of natives to introduced species: what do introductions tell us about natural communities?

“…Short‐term evolutionary responses can augment the ability of natives to exploit novel resources, or reduce fitness costs of new antagonistic interactions. Adaptations that reduce the immediate impact of invaders may include specialization on a subset of the original niche (Boyd & Barbour 1993; Vogel et al. 2002), and the evolution of evasion or resistance.…”

Does bite force provide a competitive advantage in shrews? The case of the greater white-toothed shrew

“…suaveolens was captured in the sixties and where C. russula is the only species present today, as shown by extensive trapping performed in the 1990s (Pascal et al ., ). Two others examples are provided by the displacement of C. leucodon by C. russula in Switzerland over the past 20 years (Vogel et al ., ) and by the decrease in abundance of the local shrew, S. minutus , in Ireland in favour of the expanding C. russula (McDevitt et al ., ). The current distributional ranges of the white‐toothed shrew in the Maghreb highlight a geographical segregation of C. russula and other shrew species, supporting the idea that C. russula may be competitively superior and capable of excluding or limiting others shrew species as competitors (Fig.…”

Shrews of the genus Crocidura from El Harhoura 2 (Témara, Morocco): The contribution of broken specimens to the understanding of Late Pleistocene–Holocene palaeoenvironments in North Africa

“…Indeed, C. russula has completely eliminated the native C. suaveolens from numerous Atlantic islands suggesting its competitive superiority (Cosson et al, 1996). A second example of its competitive superiority is found in Switzerland where it outcompetes C. leucodon (Vogel et al, 2002). Moreover, C. russula seems to be the only species currently present in the area of El Harhoura 2 as the other species C. whitakeri has neither been captured in the Témara region, nor in the rest of Morocco despite numerous trapping sessions.…”