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