The effect of prescribed burning on Pulsatilla vernalis at Marma military training area in Sweden.
Abstract
Changes in habitat have led to a decline in many species which are now threatened. One of them is the spring pasque flower Pulsatilla vernalis, which grows on well-drained soils and is sensitive to competition. The species has in the past benefited from disturbances such as grazing, mowing and forest fires. Now that these do not occur as frequently, it has been suggested that prescribed burning could be used as a conservation intervention to benefit P. vernalis. In this study, we tested whether prescribed burning in 2018 benefited a population of P. vernalis at Marma military training area, outside Älvkarleby in eastern Sweden. Due to unexpected windy conditions on the day of the prescribed burning, not all the planned area was burned. This created a natural experiment that enabled us to compare burned areas with unburned areas (control) in both heathland and forested heathland habitats. The study includes data gathered before and after the experimental treatment. We found that compared to the control areas, the burned areas had a significantly higher number of P. vernalis tufts (clusters of leaf rosettes), as well as a greater number of flower stalks per tuft. Although limited due to lack of replication, this study supports the suggestion that prescribed burning benefits P. vernalis, both in open areas as well as in forests.