DOI: 10.5061/dryad.g79cnp5tr
title: Data from: Synthesizing the relationships between food web structure and robustness

description: Species are being lost from ecosystems, and for more than 20 years,
 ecologists have sought to understand the extent to which these species
 losses trigger secondary extinctions—i.e., the additional loss of species
 following lost resources or key interactions—measured as robustness. In
 particular, ecologists aim to identify generalizable rules that explain
 which types of food webs are more or less robust to secondary extinctions.
 Food web structure, or the patterns formed by species and their
 interactions, has been extensively studied as a potential factor that
 influences robustness. However, there has not yet been a review of our
 understanding of the relationships between food web structure and
 robustness. We systematically reviewed 28 studies to identify the
 relationships between food web structures and robustness, and how the
 conclusions depend on methodological differences. More than 20 food web
 structures were reported to determine robustness, but the shape and
 direction of these relationships varied based on methodology. While there
 are not yet generalizable patterns in structure-robustness relationships,
 we find that methodological differences across studies underscored
 conflicting results, impeding the potential for generality. Based on our
 findings, we propose recommendations to improve these methods and identify
 future research questions.
description: We conducted a systematic literature review following the
 Reporting standards for Systematic Evidence Synthesis (ROSES) protocol
 from Haddaway <em>et al.</em> (2017), we described our process
 in full in Supporting Fig.1. This review involved two stages: 1. abstract
 screening, and 2. full paper review. We queried the Web of Science Core
 Collection on April 22, 2021, using the search string: TS= (((“food web”
 OR food-web) AND (robustness OR persistence OR fragility OR “cascad*
 extinction*” OR “second* extinction*”))), which yielded 1,107 papers. Our
 choice of search terms is likely biased towards English language studies,
 which we acknowledge as an important caveat. Our search terms
 intentionally do not include network structure or properties given the
 diverse vocabulary used to describe these ideas (e.g., complexity,
 structure, properties, attributes). Instead, we queried for all papers
 that considered the interactions we were interested in (i.e., trophic
 interactions in food webs) and the simulation of species losses that
 result in secondary, or cascading species losses (“robustness”). While
 there is interest in the relationship between structure and secondary
 extinctions associated with invasive species, we narrowed our review to
 consider secondary extinctions that result from species removals/losses
 (i.e., actively performed extinctions, Dominguez-Garcia <em>et
 al.</em> 2019), as opposed to from the addition of species (e.g., of
 invasive species as in Romanuk <em>et al.</em> (2017)).
 Finally, we acknowledge that robustness is only one of many ways to
 examine the stability of a community (Donohue <em>et al.</em>
 2016; Kefi <em>et al.</em> 2019; Landi <em>et
 al.</em> 2018); food webs are one of many possible types of
 ecological networks (e.g., mutualistic networks, competition networks);
 and many factors could influence the stability of a network other than
 network structure (e.g., regional species pool, invasive species,
 anthropogenic disturbance, environmental constraints; Doré <em>et
 al.</em> 2021). However, our search terms still provided a large
 pool of papers that we then screened to determine if the papers connected
 consequences of species losses (i.e., secondary extinctions) to aspects of
 network structure, properties, and characteristics. Further, even within
 this narrower search, we find substantial methodological
 differences. <strong>1.1 Abstract
 Screening</strong> Keyes screened abstracts from
 the initial 1,107 papers to exclude papers that did not meet the following
 criteria: 1. authors studied food webs, 2. authors simulated species
 losses and tracked secondary losses (i.e., calculated robustness), and 3.
 authors studied at least one food web property or structure in relation to
 robustness. We did not constrain the properties or structures to a
 pre-defined list and considered a broad definition of food web structure,
 including any food web property or network attributes that result from
 patterns in species that are present (i.e., nodes) and their interactions
 (i.e., links). Note that we excluded studies that may have simulated
 species removal if they did not explicitly quantify food web
 robustness. <strong>1.2 Full-paper review
 </strong> Of the original 1,107 papers, 28 papers
 met all three criteria (inclusion rate=2.5%). We reviewed all papers using
 a combination of free and fixed response questions on Google Forms. If one
 author was uncertain about a question, another author also reviewed the
 paper and the question was discussed. For each paper, we collected data on
 food web properties or structures studied, structure-robustness
 relationships, and methodology.
description: # Data from: Synthesizing the relationships between food web structure and
 robustness
 [https://doi.org/10.5061/dryad.g79cnp5tr](https://doi.org/10.5061/dryad.g79cnp5tr) This dataset includes data from each step of our literature review that aimed to identify whether there are relationships between food web structure and robustness. There are 5 files included. ## Description of the data and file structure There are 5 files included in this repository: Supplementary File 1: This file includes all of the papers and references considered at each stage of our review including 1. the 1,107 papers that we queried from the Web of Science Database, the first round filter of papers based on whether the abstracts met our inclusion requirements: 1. the authors studied food webs, 2.  authors simulated species losses (either computationally or by experimental removal of species), and 3. authors studied at least one food web property or structure in relation to robustness, the second round filter of papers after completing a full-text skim of any papers with 'Unclear' responses in our initial abstract review, and the final 28 papers that were included in our review [12 columns, 2366 rows excluding header]. Supplementary File 2: This file includes the Google Form responses for all articles that were double-reviewed by AK and LD [45 columns, 5 rows excluding header]. When reviewing the full papers, if one author was uncertain about the methods used in a paper, another author also reviewed the paper. We noted the reason for the double review of the data, discussed any discrepancies between the reviewers, and stored the final data in Supplementary File 3. Supplementary File 3: This file includes the final Google Form responses for all articles in the final review. Most columns correspond to a question on the Google Form and each row corresponds to a paper [44 columns, 29 rows excluding header]. The columns that include ".coded" include categories that we used to classify longer-form responses.  Supplementary File 4: This file includes all the food webs considered in all of the papers that we reviewed [12 columns, 102 rows excluding header]. We compiled metadata for each empirical food web that was used in papers included in our review. We specify the name of the food web, as well as the associated publication, location information, and the type of ecosystem, for example. Supplementary File 5: Metadata for Supplementary Data Files 1-4. This file describes, in detail all of the columns in each of Supplementary Files 1-4 [Table includes 3 columns, 69 rows excluding header]. Across all files, empty cells represent no data, and NA indicates that the column is not applicable to the row (i.e., to the paper). ## Sharing/Access information This is a section for linking to other ways to access the data, and for linking to sources the data is derived from, if any. Links to other publicly accessible locations of the data: * This data supports a manuscript in review at Ecology Letters. Keyes, A., Barner, A., and Dee, L. (in review). Synthesizing the relationships between food web structure and robustness. Ecology Letters. Data was derived from the following sources: * Web of Science query