Tage der Biodiversität 2027

The presence and composition of deadwood are key determinants of biodiversity and biogeochemical processes in forests. Deadwood decomposition is influenced by wood properties, micro- and macroclimate, and the activity and diversity of decomposer communities. However, the relationships among deadwood decay stage, habitat value for saproxylic invertebrates, microbial community diversity, and their interactions remain poorly understood. The ongoing project, DD FOR, funded over the Austrian Science Fund investigates how deadwood habitat characteristics, saproxylic insects, and wood-inhabiting fungal and bacterial communities relate to early decomposition dynamics in Central European forests. Experimental plots were established at eight sites across Austria along a broad climatic gradient (mean annual temperature: ~2-10 °C; annual precipitation sum: ~600-1.600 mm). Emergence traps deployed on 42 experimental deadwood logs of different tree species in total capture insect fauna directly associated with the substrate, while window traps characterise local saproxylic insect communities at each site. In addition, site-specific forest-management histories are assessed to investigate how past and current management may shape deadwood availability, habitat conditions, and colonisation processes. Decomposition progress (using mass loss as primary indicator) is monitored through annual measurements of wood density, volume and decay stage. Wood-inhabiting fungal and bacterial communities are characterised using short-read DNA metabarcoding, combined with morphological identification of visible fungal fruiting bodies. The combined analysis aims to identify relationships among habitat characteristics, deadwood continuity, management history, colonisation patterns, and changes in wood density. Here, we present first-year results on deadwood-associated biodiversity and early decomposition dynamics across eight different forest sites in Austria. This study will contribute to our understanding of the biotic and management-related controls of deadwood decomposition in Austrian forests, thereby providing an evidence base for deadwood management and the conservation of wood-inhabiting fungi and saproxylic insects.