High occurrence of red-listed bryophytes and lichens in mature managed forests in boreal Sweden

Successful biodiversity conservation needs to be based on reliable data regarding the distribution and abundance of species. Red Lists summarize the status of rare and declining species. Here we present the first detailed survey (10 in x 10 in resolution) of nationally red-listed bryophytes and lichens at stand level in boreal forests. 30 managed forest production stands in boreal Sweden, soon to be harvested, were surveyed in detail regarding red-listed bryophytes and lichens. On the 180 ha totally investigated, 33 red-listed species were found, representing 35% of all forest red-listed bryophytes and lichens so far recorded from this part of Sweden. The mean number of red-listed species per stand was 10 and varied between 5 and 16. Excluding three species which were so common that, given the time-limit, it was not possible to record all of their occurrences, there were on average 6 number of observations ha(-1). The presence and density exceed those earlier found in 'key habitats', defined as hot-spots for red-listed species. Almost all observations were made on trees, with 48% on living trees and 52% on dead. Altitude, area and stem volume explained 67% of the red-list species density. The results highlight the importance of unprotected areas for rare and declining species and point to a hitherto unacknowledged high biodiversity value of mature managed boreal forest stands, shaped by a less intense forestry than today's. It also raises questions regarding the use of red-listed species to identify areas of importance to biodiversity. Objective and systematic surveys of red-listed species in the forest landscape, including younger stands, are urgent.