Data from: Belowground community turnover accelerates the decomposition of standing dead wood

Standing dead trees (snags) decompose more slowly than downed dead wood
and provide critical habitat for many species. The rate at which snags
fall therefore influences forest carbon dynamics and biodiversity. Fall
rates correlate strongly with mean annual temperature, presumably because
warmer climates facilitate faster wood decomposition and hence degradation
of the structural stability of standing wood. These faster decomposition
rates coincide with turnover from fungal-dominated wood decomposer
communities in cooler forests to co-domination by fungi and termites in
warmer regions. A key question for projecting forest dynamics is therefore
whether temperature effects on wood decomposition arise primarily because
warmer conditions facilitate faster decomposer metabolism, or are also
influenced indirectly by belowground community turnover (e.g. termites
exert additional influence beyond fungal-plus-bacterial mediated
decomposition). To test between these possibilities, we simulate standing
dead trees with untreated, wooden posts and follow them in the
field across five years at 12 sites, before measuring buried, soil-air
interface and aerial post sections to quantify wood decomposition and
organism activities. High termite activities at the warmer sites are
associated with rates of post fall that are 3-times higher than at the
cooler sites. Termites primarily consume buried wood, with decomposition
rates greatest where termite activities are highest. However, where higher
microbial and termite activities co-occur, they appear to first compensate
for one another and then slow decomposition rates at their highest
activities, suggestive of interference competition. If the range
of microbial- and termite co-domination of wood decomposer communities
expands under climate warming, our data suggest that expansion will
accelerate snag fall with consequent effects on forest carbon cycling and
biodiversity in forests previously dominated by microbial decomposers.