DOI: 10.5061/dryad.3s57p
title: Data from: Land use in mountain grasslands alters drought response and recovery of carbon allocation and plant-microbial interactions

description: 1. Mountain grasslands have recently been exposed to substantial changes
 in land-use and climate and in the near future will likely face an
 increased frequency of extreme droughts. To date is not known how the
 drought responses of carbon (C) allocation, a key process in the C cycle,
 are affected by land-use changes in mountain grassland. 2. We performed an
 experimental summer drought on an abandoned grassland and a traditionally
 managed hay meadow and traced the fate of recent assimilates through the
 plant-soil continuum. We applied two 13CO2 pulses, at peak drought and in
 the recovery phase shortly after rewetting. 3. Drought decreased total C
 uptake in both grassland types and led to a loss of aboveground
 carbohydrate storage pools. The belowground C allocation to root sucrose
 was enhanced by drought, especially in the meadow, which also held larger
 root carbohydrate storage pools. 4. The microbial community of the
 abandoned grassland comprised more saprotrophic fungal and Gram (+)
 bacterial markers compared to the meadow. Drought increased the newly
 introduced AM and saprotrophic fungi:bacteria ratio in both grassland
 types. At peak drought the 13C transfer into AM fungi, saprotrophic fungi
 and Gram (-) bacteria was more strongly reduced in the meadow than in the
 abandoned grassland, which contrasted the patterns of the root
 carbohydrate pools. 5. In both grassland types the C allocation largely
 recovered after rewetting. Slowest recovery was found for AM fungi and
 their 13C uptake. In contrast, all bacterial markers quickly recovered C
 uptake. In the meadow, where plant nitrate uptake was enhanced after
 drought, C uptake was even higher than in control plots. 6. Synthesis. Our
 results suggest that resistance and resilience (i.e. recovery) of plant C
 dynamics and plant-microbial interactions are negatively related, i.e.
 high resistance is followed by slow recovery and vice versa. The abandoned
 grassland was more resistant to drought than the meadow and possibly had a
 stronger link to AM fungi that could have provided better access to water
 through the hyphal network. In contrast, meadow communities strongly
 reduced C allocation to storage and C transfer to the microbial community
 in the drought phase, but in the recovery phase invested C resources in
 the bacterial communities to gain more nutrients for regrowth. We conclude
 that management of mountain grasslands increases their resilience to
 drought.
description: Land use and drought
 effects on grassland C dynamicsData were collected from
 a common garden drought experiment in the Austrian Central Alps using
 intact vegetation-soil monoliths from an extensively managed meadow and a
 nearby abandoned grassland. The monoliths were installed in summer 2013 on
 the meadow site and pre-incubated until drought simulation was started in
 early summer 2014. The effects of land use on the response of plant C
 allocation and plant-microbial C transfer to drought and rewetting were
 studied by conducting two 13C pulse-chase labelling campaigns. A
 description of all data and abbreviations used in the excel file can be
 found in tab "0-README".Land_use-drought-alldata_V3.xlsx