The future of the Teesdale rarities in a changing climate: How will environmental alterations interact to dictate the persistence of species at their range margins?

The Upper Teesdale in Northern England is home to a number of nationally rare arctic and alpine plant species thought to be relics of the UK's glacial flora. In the face of increasing global surface air temperatures and rapidly changing farming practises, the future of these rare species is uncertain. A range of techniques, including species distribution modelling, exploratory regression analyses and experimental warming and grazing were used to asses the potential impacts on three relic species, Primula farinosa, Gentiana verna and Viola rupestris, found on Widdybank Fell, in the Upper Teesdale. Results indicate that neither increased temperatures or grazing pose a major threat to the study species. It is suggested that persistence of the species may be due to local adaptation of ecotypes, low levels of interspecific competition and temperature moderation by the nearby Cow Green reservoir.