MONITORING CHANGE IN ISOETES HISTRIX BORY (ISOETACEAE) AT ITS NORTHERN DISTRIBUTIONAL LIMIT

摘要

A re-survey of the threatened Land Quillwort (Isoetes histrix Bory) at its northernmost range extent on the Lizard peninsula, Cornwall, indicates a massive decline (>90%) in total population size since 1982 with the loss of several major sub-populations. The factors responsible for this are considered and climatic changes, particularly in the pattern of rainfall, and management practices, such as the reduction in grazing, are implicated in its decline.