The water shrew is one of the UK's most remarkable small mammals, requiring high-quality wetland habitat for welfare and survival that is increasingly under pressure from drainage and pollution.
Water shrew welfare is intimately tied to the quality of their aquatic habitat in ways that make them valuable indicators of stream ecosystem health. Their extreme metabolic rate means food shortage from prey-poor streams creates acute welfare stress quickly - a water shrew that cannot find sufficient invertebrate prey can starve within hours. Polluted streams with reduced invertebrate communities deny water shrews the continuous food supply their metabolism demands. The channelization and concrete lining of UK streams has eliminated the bankside structure and complexity that water shrews depend on for burrow sites and hunting cover. As specialists dependent on high-quality conditions in a highly modified landscape, water shrews experience welfare consequences from every agricultural and infrastructural decision affecting their stream habitats.