DOI: 10.5061/dryad.r2280gbbn
title: Drought legacy affects microbial community trait distributions related to moisture along a savannah grassland precipitation gradient

description: Ecosystem models commonly use stable-state assumptions to predict
 responses of soil microbial functions to environmental change. However,
 past climatic conditions can shape microbial functional responses
 resulting in a “legacy effect”. For instance, exposure to drier conditions
 in the field may shape how soil microbial communities respond to
 subsequent drought and drying and rewetting events.  We
 investigated microbial tolerance to low moisture levels (“resistance”) and
 ability to recover after a drying and rewetting (DRW) perturbation
 (“resilience”) across a steep precipitation gradient in Texas, USA.
 Although differences in precipitation regime did not result in differences
 in resistance and resilience of soil microbes, microbial communities
 appeared to be generally resilient and resistant across the gradient,
 suggesting that frequent exposure to drought had characterized the trait
 distributions of microbial communities. Moreover, microbial communities
 from historically drier sites used carbon more efficiently during a DRW
 perturbation suggesting that long-term drought history leaves a legacy
 effect on microbial functions. This may have been due to an indirect
 effect of drought caused via precipitation-induced differences in primary
 productivity, influencing the availability of soil organic matter to
 microbes. Alternatively, different exposures to drought might have shaped
 the microbial “readiness” to cope with the DRW disturbance. Microbial
 community composition was also linked to drought history, but was
 unrelated to variation in function.  Synthesis: exposure
 to drought can have both direct and indirect effects on soil microbial
 communities, which can result in lasting legacy effects on the functions
 they control. 
description: There are 3 types of data that can be found in this
 file:  Soil characterization data such as:
 C/N ratios, soil organic matter (SOM), soil inorganic carbon (SIC), water
 holding capacity (WHC), pH, EC, soil texture (% Sand, Clay and Silt), PLFA
 concentrations and NDVI.  Primary growth and
 respiration rate data, for the drying and rewetting (DRW) and the moisture
 dependence (MD) experiments. The data that is shown is normalized. For the
 DRW data in the first column the time after rewetting (in hours) is shown,
 and in the following columns the process rates after rewetting in each one
 of the soils from the gradiend (indicated by the MAP of the site in the
 heading of the column). In the MD data sheets in the first columns the
 moisture level (shown as % of WHC) is shown, and in the following columns
 the process rates at each one of this soil moistures in each one of the
 soils from the gradiend (indicated by the MAP of the site in the heading
 of the column). In the MD data, for each one of the measured processes
 there are 2 data sheets (rep1 and rep2) since the experiment was repeated
 twice and the data was then combined.  Calculations
 done based in the primary data. For the DRW experiment calculations of
 cumulative processes and recovery times can be found, as well as the
 cumulative processes for the continuously moist control soils. For the MD
 data, the IC 10 and IC 50 (moisture levels at whcih the processes are
 inhibited by 10% and 50% respectively) values for each one of the
 processes can be found.