Conserving Britain's biodiversity. I: Thlaspi perfoliatum L. (Brassicaceae), Cotswold Pennycress.

摘要

This paper describes the decline and conservation work carried out on the rare, statutorily-protected species T. perfoliatum in England (UK). T. perfoliatum has been recorded historically in a total of about 45 native and 37 introduced sites. Surveys between 1986 and 1997 found populations in 9 native sites and 3 introduced sites, suggesting an 80% loss of native and 92% loss of introduced colonies. The main reasons for decline are probably agricultural improvements, quarrying and neglect of management. T. perfoliatum is a winter annual of open grassland and screes on Oolite limestone, which requires maintenance of open conditions for long-term survival. The life history and ecology of T. perfoliatum are reviewed. Current and recommended forms ofsite management are outlined. Only 2 sites have appropriate statutory protection.