Data from: Direct and indirect impacts of climate change on microbial and biocrust communities alter the resistance of the N cycle in a semiarid grassland

1. Climate change will raise temperatures and modify precipitation
patterns in drylands worldwide, affecting their structure and functioning.
Despite the recognized importance of soil communities dominated by mosses,
lichens and cyanobacteria (biocrusts) as a driver of nutrient cycling in
drylands, little is known on how biocrusts will modulate the resistance
(i.e., the amount of change caused by a disturbance) of the N cycle in
response to climate change. 2. Here, we evaluate how warming (ambient vs.
~2.5ºC increase), rainfall exclusion (ambient vs. ~30% reduction of total
annual rainfall) and biocrust cover (incipient vs. well-developed
biocrusts) affect multiple variables linked to soil N availability
(inorganic and organic N and potential net N mineralization rate) and its
resistance to climate change during four years in a field experiment. We
also evaluate how climate change-induced modifications in biocrust and
microbial communities indirectly affect such resistance. 3. Biocrusts
promoted the resistance of soil N availability regardless of the climatic
conditions considered. However, the dynamics of N availability diverged
progressively from their original conditions with warming and/or rainfall
exclusion, as both treatments enhanced N availability and promoted the
dominance of inorganic over organic N. In addition, the increase of
fungal: bacterial ratio and the decrease of biocrust cover observed under
warming had a negative indirect effect on the resistance of N cycle
variables. 4. Synthesis. Our results indicate that climate change will
have negative direct and indirect (i.e. through changes in biocrust and
microbial communities) impacts on the resistance of the N cycle in dryland
soils. While biocrusts can play an important role slowing down the impacts
of climate change on the N cycle due to their positive and continued
effects on the resistance of multiple variables from the N cycle, such
change will progressively alter N cycling in biocrust-dominated
ecosystems, enhancing both N availability and inorganic N dominance.