Sarracenia purpurea subsp. purpurea (Sarraceniaceae) naturalised in Britain and Ireland: distribution, ecology, impacts and control

Abstract

Abstract Sarracenia purpurea subsp. purpurea is a North American carnivorous plant that has been deliberately planted on lowland bogs and mires throughout Britain and Ireland since the late nineteenth century. Since then, established populations have been reported from 38 sites where it has often been conserved for ‘scientific’ reasons. Although there are now several large, long-established colonies, any impacts on native species have been localised due to limited waterborne dispersal of seed. Where plants occur at high density, these impacts have included the displacement of Sphagnum and associated flora, most notably epiphytic liverworts. Many small populations have been successfully removed by hand but on larger sites significant regeneration has occurred from juveniles and the seed-bank. The relative effectiveness of other control measures (e.g. chemical treatment, turf-stripping) is currently under investigation. In conclusion, S. purpurea subsp. purpurea is unlikely to pose a significant threat to native species if control is carried out soon after introduction and regeneration is carefully monitored. The removal of large, established populations, however, will be much more challenging as the control measures required (e.g. chemical treatment, turf-stripping) are unlikely to be acceptable on sensitive sites supporting assemblages of rare and threatened plants and insects.