Ecology and conservation of red-listed wood-decay fungi of oak

Old coarse oaks (Quercus spp.) provide richly diverse habitats for many organisms, including nearly 600 red-listed species in Sweden. Since the 1800s, changing land use and severe exploitation of oaks have caused old coarse oaks to become extremely rare; limited to small scattered populations or individual trees and even absent from large areas.

Coarse old oaks are uniquely high in biodiversity and have strongly declined during the last two centuries in Europe, endangering many insects, lichens and fungi. A large portion of these old oaks exist in Sweden and provide habitats for roughly 600 red-listed species, of which 170 are fungi. Thus, how these habitats can be managed in order to preserve biodiversity remains a pressing issue in Sweden and other countries. A major challenge exists in bridging the generation gap between common young oaks with low conservation values and sparse coarse old oaks with high conservation values. However, it may be possible to alter younger oaks by mimicking natural damages found on very old trees; consequently accelerating valuable habitat production. This approach was initiated in the UK circa 1990s and soon made its way to Sweden, where it is presently being tested on beetle ecology in a Swedish LIFE study (Bridging the Gap 2016-2022). This project explores this concept for fungi and aims to provide management guidelines for these species of conservation interest by combining population genetics analysis and 40-years of ecological observation data. DNA-analyses of fungal communities in young oaks veteranised in 2012 and live oaks inoculated in 1999–2000 using five species of red-listed oak fungi will develop this idea further. Two species will be in focus: the rare and critically threatened orange polypore (CR) Hapalopilus croceus compared to the widespread but declining near-threatened beefsteak fungus Fistulina hepatica (NT). This proposed work would be cost-efficient as it takes advantage of an ongoing genetics study of H. croceus, cooperates with continuing oak-veteranisation/inoculation investigations, and utilises 40 years of unique Swedish oak ecology data. The project will provide deeper insight on the ecology of threatened oak fungi and aim to provide guidelines for landowners and others working with conservation.