Endophytes dominate fungal communities in six-year-old veteranisation wounds in living oak trunks

Audrius Menkis,Björn Nordén,Jonas Hedin,Anders Dahlberg,Mats Niklasson,Vikki Bengtsson,Deanne Redr

doi:10.1016/j.funeco.2020.101020

Abstract

Old trees are rare in the landscape, as are many of their associated species. Veteranisation is a method by which attempts are made to create microhabitats, otherwise found only in old trees, in younger trees at an earlier stage than would occur naturally. Here, we analysed the early fungal succession in 6 y-old veteranisation wounds in ca. 100 y old living oak trunks by DNA-barcoding of the wood at eight sites in Sweden and Norway. We hypothesised basidiomycetes would be most abundant, and exposed sapwood and heartwood would select for different communities. We identified 686 fungal taxa, mainly ascomycetes, with a large overlap in species composition and surprisingly similar species richness, i.e. 325 vs. 308–360, between intact and different types of damaged wood, respectively. Endophytes continued to be present and common in damaged wood. The results demonstrate that damage to sapwood and heartwood partly select for different fungi and that 6 y is too early to evaluate if veteranisation can positively favour fungi of conservation interest.

Highlights

In central and northern Europe, oaks (Quercus robur and Q. petraea), especially old ones, provide unique habitats and support an exceptionally high biodiversity, and are often considered as biodiversity hotspots (Molder et al, 2019)
At a subset of these veteranisation sites, we investigated the richness and species composition of wood-inhabiting fungi in veteranisation wounds of living oaks i.e. to what extent, at least initially, they may contribute to the fungal communities developing after wood damage and whether different types of damage may select for varying fungal communities
The results demonstrated that intact oak wood (C) was inhabited by a surprisingly species-rich (325) community of fungi, largely composed of unidentified taxa that occurred at low abundances (Fig. 3, Tables 1 and 2)

Summary

Introduction

In central and northern Europe, oaks (Quercus robur and Q. petraea), especially old ones, provide unique habitats and support an exceptionally high biodiversity, and are often considered as biodiversity hotspots (Molder et al, 2019). Living in closed forests for 300 y, 400e600 y in open woodlands, and more than 1000 y under optimal conditions (Niklasson and Nilsson 2005; Drobyshev and Niklasson 2010), oaks have a higher species richness and associated organism diversity per tree than any other tree in Fennoscandia. This in the context of the species only constituting 0.3e1.3% of the tree biomass (Tingstad et al, 2018). About 770 oak-associated species are nationally red-listed in the Nordic countries; about 400 of these species are wood-inhabiting, of which about 300 are beetles and 50 are fungi (Tingstad et al, 2018)

Methods

Results

Conclusion