Wood decay is an important process that releases carbon to the atmosphere and is largely mediated by fungi and bacteria. Variability in decay is shaped by endogenous (e.g. construction and chemistry) and exogenous (e.g., climate and topographic position) factors. However, the relative role of these factors on wood-dwelling microbes, the gatekeepers of decay, is less well understood. To understand how wood species identity and microclimate structure microbial communities, we used high-throughput amplicon sequencing to evaluate fungal and bacterial community composition after 1, 3 and 5 years of decay on 21 woody plant species from “rot plots” distributed across ridgetop and valley bottom habitats located in 4 watersheds in a temperate deciduous forest in MO, USA. In addition, we measured initial wood traits to characterize species differences in wood construction and chemistry.
Results/Conclusions
We found that wood species identity is a stronger determinant of wood-dwelling microbial communities than microclimate conditions relating to the position of the plot in the watershed and the position of the sample in the log. Moreover, species’ wood traits relating to wood construction and chemistry captured the majority of the variation in microbial community composition explained by wood species. We observed that the similarity of microbial communities increased among wood species over time. Moreover, fungal communities sampled from the top and bottom of logs became more dissimilar over time; whereas, bacterial communities were consistently dissimilar in those microhabitats. Lastly, fungal and bacterial communities co-varied; however, fungal composition was better explained by wood identity and microclimate variables than bacterial composition and vice versa. These results suggest that the signature of wood species identity has a long lasting impact on microbial composition that may have important implications for decay trajectories.