DOI: 10.5281/zenodo.4322924
title: Variation in biomass allocation and root functional parameters in response to fire history in Brazilian savannas

description: Dataset associated with the manuscript "<strong>Variation in biomass allocation and root functional parameters in response to fire history in Brazilian savannas" </strong> (Le Stradic et al.). It includes 5 different datasets and for each one we provided metadata. above_below_b_SBI: it includes data related to aboveground and belowground biomass. Aboveground data were collected in circular plots of 0.5m2 and belowground biomass was collected using an auger of 5cm of diameter, every 10cm up to 40cm and every 20cm up to 1m depth. See the method section in the manuscript for full details. below_b_wet_all_SBII: it includes data related to belowground biomass (collected in the first 1m of soil, during the wet season, January-February 2018), including values for each soil depth. root_trait_SBI: it includes all root functional parameters for samples collected in the first 10 cm of soil. Sampling_data: it includes information associated with sampling areas (localization, GPS point, fire history). soil.expand.SBI: it includes all soil data. <strong>Abstract</strong> Fire is a fundamental ecological factor in savannas because it affects vegetation dynamics and ecosystem functioning. However, the effects of fire on belowground compartments, including biomass and root traits, and their regeneration remain poorly understood. In this study, we assess the variation of above- and belowground plant components along fire-history gradients in Brazilian open savannas and investigate whether vegetation and soil composition changes are associated with the responses of belowground biomass and root traits. The study was conducted in eight sampling areas of open savanna (<em>campo sujo</em>) the Cerrado (Brazilian savannas), located along a gradient of time since the last fire (1–34 years); the number of fires that occurred within the past 34 years (0–9 fires) varied by sampling area. In each sampling area, we measured above- and belowground biomass, root depth distribution, root functional parameters, and nutrient levels in the upper soil layers (0–10 cm). Rapid recovery of aboveground live biomass after a fire was primarily due to resprouting of graminoids. This recovery was associated with an increase in absorptive root biomass in the upper soil layer in the most recently burnt sites, whereas root biomass was unaffected in deeper layers. Root parameters remained constant regardless of fire history but responded to variations in vegetation structure and soil resources. Specific root length (SRL) decreased with K, Mg<sup>2+</sup>, Al<sup>3+</sup>, N, and C and increased with P concentration. In contrast, root tissue density (RTD) and absorptive root proportion were negatively correlated with soil P. RTD was strongly associated with the aboveground biomass of graminoids. Soil texture impacted the root system: the proportion of absorptive root increased with fine sand content in the soil, inversely to transport root biomass. The relationship between fire and soil composition was insignificant. <em>Synthesis</em>. In savannas, fire stimulates absorptive root biomass in response to the higher demand for belowground resources. This response is correlated with shoot regrowth after a fire. Variations in morphological root parameters are not directly associated with fire history; instead, they reflect differences in soil chemistry, especially soil P and graminoid biomass changes.
description: Funding from FAPESP (#2016/13232-5 and #2018/03755-6, #2015/06743-0), CNRS PICS 2018-2020 [RESIGRASS] grant and National Geographic Grant (NGS-51903C-18).