The water shrew Neomys fodiens is one of Britain’s least known mammals and its habitat requirements are poorly understood. The purpose of this study was to determine occurrence and associated habitat preferences of water shrews, a species of conservation concern, by comparing populations in central England freshwater habitats. Bait tube surveys were undertaken at 32 freshwater sites to establish water shrew presence, half of which were found to contain water shrews. Habitat surveys were undertaken and, in addition to water shrew presence/absence data, were used to develop habitat suitability index models by means of artificial neural networks. Management intensity (occasional or frequent bankside management) was identified as the most important predictor of water shrew presence and, when combined with dissolved oxygen (0-2.99mg l-1) and water depth (<25cm), created the highest performing model. These models will allow sites to be rapidly assessed for water shrew presence without labour intensive and costly live-trapping techniques. Prey availability was investigated by undertaking invertebrate surveys at four water shrew-positive sites, as well as at an additional four sites with unknown water shrew presence with which to compare. Overall, there was no significant difference between the total numbers of terrestrial and aquatic invertebrates at sites with known/unknown water shrew presence although there were differences in composition of potential prey. POPAN abundance of water shrews was estimated, and its relationship with other small mammal species investigated, using live trapping at the four water shrew positive sites. Negative relationships were found between water shrews and the terrestrial shrew species although these were not significant. Individually identifying captured water shrews using traditional fur-clipping marking methods is difficult. Therefore, buccal swab samples were taken to identify individuals via genetic profiling. Determining numbers of water shrews via genetic profiling was found to be more accurate than through fur-clipping which overestimated populations. Furthermore, buccal swab sampling is a new, minimally invasive method of identifying individuals which can be used to give accurate information about water shrew population densities and dynamics across seasons. This is the first in-depth study of factors affecting the occurrence and habitat selection of water shrews in central England and has made some important contributions to the understanding of habitat analysis and species identification.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:629276 |
| Date | January 2012 |
| Creators | Champneys, A. |
| Publisher | Nottingham Trent University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://irep.ntu.ac.uk/id/eprint/100/ |
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