Abstract:
Heavy natural disturbance in large protected areas of former commercial forests increasingly evokes
European parliaments to call for management intervention because a loss of habitats and species is
feared. In contrast, natural early successional habitats have recently been recognised as important for
conservation. Current knowledge in this field mostly results from studies dealing only with selected
taxa. Here we analyse the success of species across 24 lineages of three kingdoms in the Bavarian Forest
National Park (Germany) after 15 years of a European spruce bark beetle (Ips typographus L.) outbreak
that led to rapid canopy opening. Using indicator species analysis, we found 257 species with a significant
preference for open forests and 149 species with a preference for closed forests, but only 82 species with
a preference for the stand conditions transitional between open and closed forests. The large number
of species with a preference for open forests across lineages supports the role of this bark beetle as
a keystone species for a broad array of species. The slowdown of the outbreak after 15 years in the
core zone of the national park resulted in less than half of the area being affected, due to variability in
stand ages and tree species mixtures. Our case study is representative of the tree species composition
and size of many large protected montane areas in Central European countries and illustrates that (1)
natural disturbances increase biodiversity in formerly managed forests and (2) a montane protected area
spanning 10,000 ha of low range mountains is likely sufficient to allow natural disturbances without a
biased loss of closed-forest species.
