DOI: 10.5061/dryad.rn8pk0pp6
title: Warming and reduced rainfall alter fungal necromass decomposition rates and associated microbial community composition and functioning at a temperate-boreal forest ecotone

description: Changes in temperature and rainfall associated with altered climatic
 conditions are likely to significantly alter rates of soil organic matter
 decomposition. To determine how the combined effects of warming and
 drought impact the decomposition of fungal necromass, a large and
 fast-cycling portion of the global soil organic carbon (C) pool, we
 incubated Hyaloscypha bicolor necromass under both ambient and altered
 conditions (air and soil warming +3.3°C and ~40% reduced rainfall) at the
 B4Warmed experiment in Minnesota, USA. We conducted two multi-week
 incubations, one assessing mass loss and microbial community composition
 on decaying necromass after 1, 2, 7, and 14 weeks and the second
 characterizing the substrate utilization capacities of
 necromass-associated microbial communities after weeks 1 and 7. Warming
 and reduced rainfall accelerated the initial rate of necromass decay by
 ~20%, yet slowed overall mass loss by ~6% at the end of the 14 week
 incubation. These different rates of decay over time paralleled shifting
 abiotic conditions, with altered plots experiencing warmer and relatively
 moist conditions early, but hotter and drier conditions later. The
 microbial community composition also varied by treatment and time, with
 warming and reduced rainfall stimulating fast-growing fungi as well as
 fungal relative to bacterial growth overall. Additionally, the functional
 capacity of the microbial community also changed over time, having a
 higher metabolic capability to utilize C and N substrates in the altered
 plots early in decomposition but a lower capability later in decay.
 Collectively, our findings highlight a dynamic, stage-dependent response
 of fungal necromass decomposition to altered climate regimes. By linking
 these decay dynamics to shifts in environmental conditions as well as
 microbial community composition and function, our study highlights the
 critical roles of both abiotic and biotic changes in mediating
 decomposition responses to climate change.
description: # Warming and reduced rainfall alter fungal necromass decomposition rates
 and associated microbial community composition and functioning at a
 temperate-boreal forest ecotone Dataset DOI:
 [10.5061/dryad.rn8pk0pp6](10.5061/dryad.rn8pk0pp6) ## Description of the
 data and file structure This data was collected to determine the impact
 that experimental warming and reduced rainfall has on decomposing fungal
 necromass in a temperate-boreal ecotone. We incubated fungal necromass and
 determined mass loss across time (1, 2, 7, and 14 weeks), sequenced the
 associated bacterial and fungal communities, and assessed microbial
 substrate utilization using biolog eco plates. ### Files and variables
 #### File: B4W_Necro_MassLoss.csv **Description:** Mass loss measurements
 for the 14-week incubation. Missing values are labeled as NA. #####
 Variables * Plot : Plot ID based on 3 different blocks. * Plot_ID: The ID
 of the bag tags. * set: Respective set associated with each group of bags.
 * Treatment: Treatment type. * Harvest_date: Date of harvest *
 Harvest_time: Time frame of harvest * Day: Time necromass was incubated in
 days * Year: Time necromass was incubated in years * Mass_intial: Initial
 necromass mass deployed (in grams) * Mass_initial_per: Initial necromass
 deployed as a percentage * Mass_tube: The mass (in grams) of a clean and
 sterile microcentrifuge tube  * Mass_tube_wet: The mass of the micro
 centrifuge tube with necromass harvested (before freeze drying) *
 Mass_harvest_wet: The mass of the necromass only (before freeze drying) *
 Mass_tube_dry: The mass of the micro centrifuge tube with necromass after
 freeze drying * Mass_harvest_dry: The mass of the necromass only after
 freeze drying * Ratio: The wet to dry ratio
 (mass_harvest_wet/mass_harvest_dry) * Mass_prop_rem: Mass proportion
 remaining after incubation * Mass_prop_rem_per: Mass proportion remaning
 percentage * Mass_lost : Total mass lost * Mass_prop_lost: Mass proportion
 lost * Mass_prop_lost_per: Mass proportion lost percentage *
 B4W_coordinates: coordinate of where each bag was deployed  #### ####
 File: 16S_combined_sequences_taxa_silva.txt **Description:** Bacterial
 (16S rRNA) sequences from necromass bags and adjacent soil.  #### ####
 File: ITS_combined_sequences_taxa.txt **Description:** Fungal (ITS)
 sequences from necromass bags and adjacent soil.  
 
 #### File: B4W_Bio_Loss.csv **Description:** Mass loss measurements for
 the 7-week incubation. Missing values are blank. ##### Variables *
 Plot_ID: Plot location  * Tag_ID: Tag of bag * Treatment: Treatment type *
 B4W_coordinates: coordinate of where each bag was deployed  *
 Harvest_date: Date of harvest * Day: Time necromass was incubated in days
 * Year: Time necromass was incubated in yearsMass_intial: Initial
 necromass mass deployed (in grams) * Mass_initial_per: Initial necromass
 deployed as a percentage * Mass_tube: The mass (in grams) of a clean and
 sterile microcentrifuge tube  * Mass_tube_wet: The mass of the micro
 centrifuge tube with necromass harvested (before freeze drying) *
 Mass_harvest_wet: The mass of the necromass only (before freeze drying) *
 Mass_tube_dry: The mass of the micro centrifuge tube with necromass after
 freeze drying * Mass_harvest_dry: The mass of the necromass only after
 freeze drying * Ratio: The wet to dry ratio
 (mass_harvest_wet/mass_harvest_dry) * Mass_prop_rem: Mass proportion
 remaining after incubation * Mass_prop_rem_per: Mass proportion remaning
 percentage * Mass_lost : Total mass lost * Mass_prop_lost: Mass proportion
 lost * Mass_prop_lost_per: Mass proportion lost percentage 
 
 #### File: B4W_Climate_2023.csv **Description:** Temperature and
 precipitation measurement summaries for the dates this experiment was
 deployed.  ##### Variables * date: date of measurement * time: time of
 measurement * AM_PM: morning or afternoon of measurement * site: location
 site * canopy: canopy type (open or closed) * plot: plot id * year: year
 of measurement * month: month of the year * week: week of the year * hour:
 hour measurement number of the day * block: block number -
 warming_treatment: warming treatment - water_treatment: water treatment  -
 power: power (on =1, off =0) - AbovegroundTempC: Temperature aboveground
 (lamps) - BelowgroundTempC: Temperature below ground (wires) -
 relativeHumidity:  relative humidity % - VWC: Volumetric Water Content of
 the soil 
 
 #### File: FungiLogCopies.csv **Description:** qPCR data from fungi (ITS)
 for 7-week incubation ##### Variables * Number: Number of sample *
 SampleID: Sample ID (Plot, Day, Replicate) * Treatment: Treatment type *
 Day: incubation days * Replicate: Replicate or Biolog number * AverageCt:
 average cycle threshold * Copies: Fungal copies * Copies_uLDNA: Fungal
 copies per uL used * Copies_uLDNA_Diluted: Fungal copies per uL used
 diluted * Copies_per_gram: uL of Fungal copies per gram of necromass used
 for DNA extraction * LogCopies_per_gram: fungal copies (log transformed)
 per gram of necromass used for DNA extraction #### File:
 BacteriaLogCopies.csv **Description:** qPCR data from bacteria (16S rRNA)
 for 7-week incubation ##### Variables * Number: Number of sample *
 SampleID: Sample ID (Plot, Day, Replicate) * Treatment: Treatment type *
 Day: incubation days * Replicate: Replicate or Biolog number * AverageCt:
 average cycle threshold * Copies: Bacterial rRNA copies * Copies_uLDNA:
 Bacterial copies per uL of DNA added per reaction * Copies_uLDNA_Diluted:
 Bacterial copies per uL of diluted DNA * Copies_per_gram: bacterial copies
 per gram of necromass used for DNA extraction * LogCopies_per_gram:
 bacterial copies (log transformed) per gram of necromass used for DNA
 extraction #### File: Bacteria_RA.csv **Description:** Processed Relative
 abundance data for bacterial ASVs that have been clustered by genus. The
 first column is the genus, and subsequent columns are the different
 samples. Refer to B4W_Times for sample ID details.  * Genus: Bacteria
 genera #### File: Fungi_RA.csv **Description:** Processed Relative
 abundance data for fungal ASVs that have been clustered by genus. The
 first column is the genus, and subsequent columns are the different
 samples. Refer to B4W_Times for sample ID details.  * Genus: Fungi genera
 #### File: B4W_Times.csv **Description:** Processed Relative abundance
 data for fungal ASVs that have been clustered by genus. The first column
 is the genus, and subsequent columns are the different samples. Refer to
 B4W_Times for sample ID details.  * SampleID: Sample names. Samples
 beginning with a capital S are soil samples.  * Day: how long necromass
 bags were incubated for. Initial soil samples are labeled as
 "0".  * TimeFrame: The associated time frames based on decay
 fractions; initial, k (days 7 and 14) and A (days 49 and 98). * Treatment:
 The associated treatment types; altered (3.3C_redR) and ambient
 (ambC_ambR). Soil samples are labeled with "soil" at the
 beginning. * Deployment: When samples were deployed. June is the longest
 incubation used to assess mass loss and community composition while the
 August deployment is the short incubation used to assess microbial
 activity. Initial refers to initial soil samples (no necromass or
 incubation) * Harvest: Exaact dates for each harvest as month/day/year *
 Block: The associated block name for each condition/treatment.  * Set: The
 associated "set" that was determined by each plot quadrant.
 Please refer to experimental layout for details  
 
 ## Code/software All analyses and data visualization were conducted in R
 and R studio. Primary packages used were tidyverse, vegan, cowplot, bbmle,
 nortest, and other. Exact scripts used for this study can be found at
 GitHub: [https://github.com/AnahiCantoran/B4Warmed_Necromass](https://github.com/AnahiCantoran/B4Warmed_Necromass)