AbstractIn the face of changing environments, conservation is tending towards an adaptive framework which accounts for the movement of species in the landscape. This makes it necessary to quantify population dynamics of species of concern. We studied the nationally scarceCladonia botrytes, a priority Biodiversity Action Plan species in Britain, examining population dynamics at two scales: first, we studied the demography for two populations over a period of 13 years. The monitored populations declined to complete absence, starting from 77 mats on 19 stumps. Individual mats persisted maximally for up to 7 years, but over 78% of more than 290 individual cases persisted only 1 year, and more than 93% of mats disappeared within 3 years. Secondly, we performed a targeted regional survey of more than 800 stumps across an additional 27 sites in the centre of the lichen's distribution in Britain in 2006. The largest populations known from 1998 were revisited and found to no longer support the species; only 9 stumps in 5 sites supportedC. botrytesin 2006. We show thatC. botrytesin Britain is characterized by short individual and population persistence times, probably locally dependent upon vegetative succession including overgrowth and shading, and the degree of stump decay. The species' transient nature poses a particular challenge to conservation, though we identify comparable systems from which lessons may be learned.
A life‐history perspective on the demographic drivers of structured population dynamics in changing environments