An example of how to build conservation evidence from case studies: Fire and raking to enhance Pulsatilla vernalis populations

Can data collected by practitioners during practical conservation work be used as decision support? To find out, we used unpublished data from attempts to enhance populations of the vascular plant Pulsatilla vernalis in Sweden. About half of the 50 located cases had generated data useful for meta-analysis. We could show that burning had a positive effect while mechanical disturbance had negligible effects on number of plants in short-term follow-ups. Furthermore, we suggest that follow-up variables related to flowering are inferior for monitoring intervention success as flowering varies greatly between years. In the broader context, our example shows that simple records from practical conservation work can be a rich source of information. It was also obvious that there is great potential for more useful evidence by making just small improvements in field protocols, documentation, and archiving. Finally, we suggest that biologists and researchers need to develop an appreciation of “different levels of evidence”, and that in circumstances where we lack relevant experiments or observational studies, case studies might be useful for improving interventions.