Effects of prescribed burning and wildfires on Orthoptera in Central European peat bogs

Abstract

Fire has become a frequent tool in nature conservation and hazard reduction, but there is still dispute about the responses of many taxa, especially concerning invertebrate populations. While the effects of fire on plants and animals have been examined intensively in prairies, savannahs and coniferous forests, wetlands have rarely been considered in this context, yet wetland ecosystems do experience periodic fires. This study examines the effects of prescribed burning and wildfires on Orthoptera in four Central European peat bogs. All species persisted on the burned plots and none experienced a massive decline in abundance compared to unburned treatments. Generally, differences in species composition and abundance were more distinct between the bogs than between the fire treatments or fire season. One threatened species, Omocestus rufipes, occurred more often in burned than in unburned samples. The abundances of Orthoptera species in the transition zone between burned and unburned plots were either uniform or step-like rather than gradual in nature, conflicting with a hypothesis of post-fire recolonization from unburned plots. This pattern supported by non-metric multidimensional scaling suggests that the vegetation structure plays a substantial role in habitat choice of these insects. Small-scale fires between February and May do not seem to represent a threat to Orthoptera species. However, in the longer term, peat bog restoration may be affected by negative vegetation responses.