Data for: Drivers of wood decay in tropical ecosystems: Termites vs. microbes along spatial, temporal and experimental precipitation gradients

Models estimating decomposition rates of dead wood across space and time
are mainly based on studies carried out in temperate zones where microbes
are dominant drivers of decomposition. However, most dead wood biomass is
found in tropical ecosystems, where termites are also important wood
consumers. Given the dependence of microbial decomposition on moisture
with termite decomposition thought to be more resilient to dry conditions,
the relative importance of these decomposition agents is expected to shift
along gradients in precipitation that affect wood moisture. Here, we
investigated the relative roles of microbes and termites in wood
decomposition across precipitation gradients in space, time and with a
simulated drought experiment in tropical Australia. We deployed mesh bags
with non-native pine wood blocks, allowing termite access to half the
bags. Bags were collected every six months (end of wet and dry seasons)
over a four-year period across 5 sites along a rainfall gradient (ranging
from savanna to wet sclerophyll to rainforest) and within a simulated
drought experiment at the wettest site. We expected microbial
decomposition to proceed faster in wet conditions with greater relative
influence of termites in dry conditions. Consistent with expectations,
microbial-mediated wood decomposition was slowest in dry savanna sites,
dry seasons, and simulated drought conditions. Wood blocks discovered by
termites decomposed 16% to 36% faster than blocks undiscovered by termites
regardless of precipitation levels. Concurrently, termites were 10 times
more likely to discover wood in dry savanna compared with wet rainforest
sites, compensating for slow microbial decomposition in savannas. For wood
discovered by termites, seasonality and drought did not significantly
affect decomposition rates. Taken together, we found that spatial and
seasonal variation in precipitation are important in shaping wood
decomposition rates as driven by termites and microbes, although these
different gradients do not equally impact decomposition agents. As we
better understand how climate change will affect precipitation regimes
across the tropics, our results can improve predictions of how wood
decomposition agents will shift with potential for altering carbon fluxes.