Plant litter decomposition is a major source of CO2 emissions, and its prediction is crucial for global climate models. Unfortunately, these models consistently underestimate decomposition rates in drylands (which cover 40% of global terrestrial biome) suggesting that some mechanisms have not been fully explored. In arid ecosystems aboveground litter constitutes over half of plant biomass but its decomposition is overlooked in climate models. Since plant litter decomposition is driven by fungi, understanding the strategies that fungi use in decomposition is needed to better model these systems. In the hyper-arid Namib Desert (grassland dominated by Stipagrostis sabulicola) another study found that 66% of endophytes, microbes found in living plants, are able to decompose plant litter after the plant died, suggesting endophytes could have an advantage in decomposition by colonizing plants first. However, the energy cost of role switching may make them less competitive at later stages of decomposition compared to other decomposers only found in dead litter. To test this, we incubated early and late stage litter of S. sabulicola with saprophytic endophytes and decomposers isolated from dead litter for 28 days to see whether they specialize in decomposing early versus late stage litter.
Results/Conclusions
Fungi isolated from living tissue, dead litter, air, and fog all decomposed grass litter at an equal rate. Our results show that microbes from this system are generalists in decomposing early and late stage litter. Exploring the function these microbes play in their environment allowed us to understand what they are doing. This can lead to conclusions about the importance of studying the actual microbes and potentially improve global climate models.