The debate about whether proactive (focused on irreplaceable species) or reactive (focused on vulnerable
species) conservation is more effective usually focuses on the global or multinational scale and knowledge
of how these principles interact on-the-ground is lacking. Here we use the first long-term dataset
on an entire oak-living beetle community in hollow oaks (Querulous spp.) to ask whether policy-driven conservation
actions aimed at vulnerable species can also be proactive for unthreatened, but irreplaceable
species. Hollow oaks are vital keystone structures that are rich in both vulnerable and irreplaceable
wood-living beetles. We sampled in excess of 23,000 individuals from 307 species over four seasons,
across the oak range in Norway. We assessed the importance of key environmental variables for vulnerable,
irreplaceable and generalist species. We show that simple management actions taken to benefit vulnerable
species in hollow trees could also contribute to preventing the decline of important, irreplaceable
species. Clearing regrowth is predicted to increase vulnerable species richness by 75–100%, specialist
richness by 65%, and to benefit two generalist species. Regrowth clearance is likely to be similarly beneficial
in all oak-based habitats with hollow trees across Europe and North America. Increased oak circumference
and local habitat quantity were also beneficial for species richness and influenced species
composition. Based on this we provide advice for targeting conservation action. We suggest economic,
carbon and recreational benefits of clearance that could increase the attractiveness of conservation for
policy-makers. We show the importance of examining large-scale conservation planning principles at a
local scale to elicit how they work on the ground where conservation actually happens.
2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-SA license