Add-On Studies

 

Background. In addition to being a distributed experiment designed to address core questions, NutNet also can serve as globally distributed infrastructure for additional studies that generate new response variable data from many sites. Designed well, such new ‘add-on’ data campaigns can leverage the NutNet experimental infrastructure via collaboration by each site-PI to advance knowledge across the discipline. Add-on data collection is not required for any site; each add-on provides an optional opportunity
to contribute (data and intellectually) to additional questions and analyses. This add-on approach has been incredibly productive – investigators have led add on studies of long-term decomposition, soil and foliar microbiomes, herbivory and infection, arthropod diversity/biomass/functional groups, root biomass, and many more (see table below).


Philosophy and practice of add-ons. One of the central principles of NutNet is that although NutNet scientists are participating in maintaining the experimental treatments and generating the core data, everyone is busy, and everyone is low on funds.


Add-ons are done on the premise that any work you ask others to do:

  • will turn into new knowledge and at least one publication;
  • will provide opportunities for intellectual engagement by those generating the new dataset (manuscripts will follow the opt-in process for those contributing add-on data – in a sense, intellectual engagement opportunities are traded for time and effort to help generate the dataset);
  • will not have a long-term impact on the experimental plots;
  • will not have a heavy burden of time or effort for collaborators/data contributors – the proposing lab will fund the work (other than field collection) – including materials, permits, shipping, sample processing, etc.
  • will be shared and stored as data within the central NutNet database;

The most successful add-ons are hypothesis-driven, involve minimal work for site investigators, and generate exciting and unique data that will be broadly used for analyses beyond the initial publications. Add-ons generally are inclusive and open to the
whole network, because the strength of NutNet is in the replication across globally relevant gradients. That said, some add-ons may only be appropriate to specific regions or a subset of sites (e.g., study using a specific focal species).

Proposing an add-on study. All add-ons must be proposed and approved prior to communicating with the network. We have a lot of experience in helping to make these successful in an international network – please talk to us at HQ before proposing
an add-on study.

To propose an add-on, create a short document with the following components:

  • Hypotheses/abstract. Write a clear background, hypotheses, questions, and/or a mock abstract (or more than one) so potential contributors can assess the cost-benefit tradeoffs for their scientific interests and site constraints as they decide whether their site will contribute.
  • Proposed research plan. Describe the new data type and how it will be measured; include potential short- and long-term impacts to the experimental plots. Protocols should be pilot tested prior to submitting add-on proposal.
  • Individual site costs. Describe site costs and required effort as well as costs that will be paid by the proposing investigator.
  • Products. Briefly describe projected end products (datasets and manuscripts).

In the review and approval process, we will consider:

  • feasibility (time, costs – don’t forget shipping both directions, if necessary)
  • clarity of protocols and expertise level required for contributing sites
  • potential short- and long-term impacts to the experimental plots
  • likelihood to generate exciting, usable data
  • results of your pilot test of the protocols, including honest time estimates
  • plans for ensuring consistency among sites
  • opportunities to join forces with others in the network proposing related work (e.g., soil microbial biomass, root biomass, microbial metagenomics, and soil chemistry could all come from the same soil cores, but be led and funded by different labs)

 

List of NutNet Add-on Studies

ThemeNew data typePIPublications
Abiotic

Wet N Deposition

 Laurie Biderman

Stan Harpole

 

Belowground

[belowground set 1, NutNet all soils]

NutNet soil CN, micronutrient, and texture

Anita Krause

Eric Seabloom

Elizabeth Borer

Many

Belowground

[NutNet all soils]

C:N in SOM, MAOM, & POM, and proportion C & N in MAOM

Katie Rocci

Francesca Cotrufo

Rocci et al. 2022
Belowground

Oak litter bag decomposition

Sarah Hobbie

Gill et al 2022

BelowgroundSoil nutrients from resin bagsStan Harpole 

Belowground, traits

[belowground set 1]

Root biomassElsa Cleland

Cleland et al 2019

Belowground, microbes

[belowground set 1]

Endophyte colonization of rootsJeremiah Henning

Lekberg et al 2020

Belowground, microbes

[belowground set 1]

Soil microbial communityNoah Fierer

Prober et al 2015; Leff et al 2015

Belowgroundsoil organic matter, microbial carbon use efficiency, microbial oxidative enzyme activity, microbial biomass

Charlotte Riggs

Riggs and Hobbie 2016; Riggs et al 2015

Belowground

[mineralization]

N mineralization

Anita Risch

Risch et al 2020

Belowground

[mineralization]

soil microbes and animalsNico Eisenhauer 

Belowground

[mineralization]

Root C, N

Ciska Veen

Judith Sitters

 
BelowgroundTea bag litter decompositionRaul Ochoa-Hueso

Ochoa-Hueso et al 2020

Belowground

soil organic matter, extracellular enzyme, root mass, root turnover

 Sarah Hobbie

Kirsten Hofmockel

Melanie Mayes

Keller et al 2022;

Belowground

volumetric soil water content, root water uptake

 Sven Westermann

Stan Harpole

Anke Hildebrandt

 

Belowground

[belowground set 2]

Soil organic matter priming and microbial substrate use

Anita Risch

 

Belowground

[belowground set 2]

CN and micronutrient measurements, soil, AG mass & root chemistry

Anita Krause

Eric Seabloom

Elizabeth Borer

 

Belowground, microbes

[belowground set 2]

PFLA, geochip, BioLog, root biomass

 Joe Zhou

Jailiang Kuang

 

Belowground, microbes

[belowground set 2]

roots endophyte colonization

Jeremiah Henning

 
Belowground, trophic

soil disturbance using ground penetrating radar, nutrient availability, water infiltration capacity; seed predation cafeteria survey

Mia Jessen

Anne Ebeling

Stan Harpole

Christiane Roscher

 
Microbes, traits

Andropogon leaf fungal and bacterial microbiome

Anita Krause

Eric Seabloom

Elizabeth Borer

Seabloom et al 2019; Lumibao et al 2019; Henning et al 2020

Microbes, traits

Site-level dominant grass: leaf fungal and bacterial microbiome

Anita Krause

Eric Seabloom

Elizabeth Borer

Seabloom et al in revision

Microbes, traits

Andropogon & Bromus leaf fungal and bacterial microbiome

Anita Krause

Eric Seabloom

Elizabeth Borer

 

Microbes

[belowground set 3]

Soil, plant, & microbial chemistry, water content and water holding capacity, enzyme activity, microbial traits, microbial 16S & ITS

 Richard Bardgett

Chris Taylor

Ainara Leizeaga

 

Microbes

[belowground set 3]

AMF community composition

Ylva Lekberg

 
Plant community

Woody biomass and density

Eric Seabloom

Elizabeth Borer

 
Plant community

Seedbank germination

Lauren Sullivan

Anu Eskelinen

 
Plant communitySpecies area curve, richness at multiple scale in plot

Eric Seabloom

Jon Chase

Seabloom et al 2021

Plant community, trophicMovable exclosures, ANPPAnu Eskelinen 
Plant communityRepeated cover samplingAdam Clark 
Pollinators, trophicflower abundance & richness, flower visitation rat, insect abundance & richness, fruit set

Luisa Carvalhiero

Juan Cancella

 
Pollinators, trophic

Plant communities for pollinators

Rebecca Nelson 
Traits

Leaf traits, chemistry

Jennifer Firn

Firn et al 2019

TraitsSeed traitsLauren Sullivan 
Traitsaboveground plant C, N, P, KMichael Anderson

Anderson et al 2018

Traitssymbiotic N-fixation, d15N

Per Schleuss

Marie Spohn

 Vazquez et al 2022

Vazquez et al 2023

TraitsMaximum height of all plants

Riley Gridzak

Brandon Schamp

 

Traits

[plant pairs]

leaf area, gas exchange, leaf CN & isotope

Nick Smith

Monika Kelly

 

Traits

[plant pairs]

plant genome sizeErika Hersch-Green 
Trophicseed removal by granivoresJohn Orrock

Orrock et al 2014

Trophicinsect abundance and biomass sorted to order

Lizzie Wolkowitz

Adam Kay

Elizabeth Borer

Lind et al 2017

Trophicinsect abundances sorted to family; leaf damageKim Komatsu

La Pierre and Smith 2016

Trophic

leaf herbivore and fungal damage

 Anne Ebeling

Dana Blumenthal

Ebeling et al 2021