Forgotten role of fires in Central European forests: critical importance of early post-fire successional stages for bees and wasps (Hymenoptera: Aculeata)
Abstrakt
Forest fire remains among the most controversial topics in nature conservation. Here, we address changes in abundance and species composition of the bee and wasp community following a temperate forest crown fire that led to nearly complete defoliation and dieback of trees within 2 years.
We found a highly dynamic community of 252 bee and wasp species (representing 18.8 % of total bee and wasp species known from the Czech Republic) that utilized 1-7-year-old burned forest stands. Species richness in the burned forest stands was significantly higher than that recorded in nearby forest that had been unaffected by any recent fire.
The unburned forest hosted only 88 species. We found 42 red-listed species, of which 40 were present in the burned forest, while only 12 were present in the control forest.
Numerous early- and late-responding species were detected, but maximum species diversity was reached 3 years after the fire. Only 7 of the total of 261 species were limited to the forest that was unaffected by any recent fire.
A management regime that supported the presence of bare sand and heather patches, and removal of all but solitary pine trees, was found to be insufficient to support the full spectrum of forest fire-dependent species. This was mainly due to the absence of charred or decaying dead wood, which is otherwise utilized by numerous red-listed cavity adopters that are absent in the surrounding cultural landscape.
Retaining part of the charred trunks is suggested as a novel post-fire conservation measure.