Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: A pleasing consequence of Norway rat eradication: two shrew species recover

Published source details

Pascal M., Siorat F., Lorvelec O., Yésou P. & Simberloff D. (2005) A pleasing consequence of Norway rat eradication: two shrew species recover. Diversity and Distributions, 11, 193-198


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Remove/control non-native mammals Terrestrial Mammal Conservation

A replicated, before-and-after study in 1994–2004 on five temperate oceanic islands in northern France (Pascal et al. 2005) found that after the eradication of Norway rats Rattus norvegicus, the abundance of lesser white-toothed shrews Crocidura suaveolens increased on four islands and greater white-toothed shrews Crocidura russula increased on one island. No statistical analyses were performed. Ten years after rat eradication, the abundance of lesser white-toothed shrews on four islands was greater than that before rat eradication (after: 0.09–0.14 shrews/trap night; before: 0.00–0.01). One and two years after rat eradication on a further island, the abundance of greater white-toothed shrews was greater than that before rat eradication (after: 0.31 shrews/trap night; before: 0.02). In total, Norway rats were eradicated from seven islands (0.2–21 ha) in 1994-2002 by trapping and baiting with anticoagulant rodenticide (Bromadiolone©) or using strychnine poisoning (one island in 1951). Monitoring results from five islands are reported here. Small mammal sampling was conducted with 7–269 trap stations at 6-30 m intervals in 1994-2004. Each station had two live traps and was checked daily for 3–7 days.

(Summarised by Ricardo Rocha)