DOI: 10.5061/dryad.dfn2z34zp
title: Data from: Incorporating alternative interaction modes, forbidden links and trait-based mechanisms increases the minimum trait dimensionality of ecological networks

description: Individual-level traits mediate interaction outcomes and community
 structure. It is important, therefore, to identify the minimum number of
 traits that characterise ecological networks, i.e. their 'minimum
 dimensionality'. Existing methods for estimating minimum
 dimensionality often lack three features associated with increased trait
 numbers: alternative interaction modes (e.g. feeding strategies such as
 active vs. sit-and-wait feeding), trait-mediated 'forbidden
 links' and a mechanistic description of interactions. Omitting these
 features can underestimate the trait numbers involved, and therefore,
 minimum dimensionality. We develop a 'minimum mechanistic
 dimensionality' measure, accounting for these three features. The
 only input our method requires is the network of interaction outcomes. We
 assume how traits are mechanistically involved in alternative interaction
 modes. These unidentified traits are contrasted using pairwise performance
 inequalities between interacting species. For example, if a predator feeds
 upon a prey species via a typical predation mode, in each step of the
 predation sequence the predator's performance must be greater than
 the prey's. We construct a system of inequalities from all observed
 outcomes, which we attempt to solve with mixed integer linear programming.
 The number of traits required for a feasible system of inequalities
 provides our minimum dimensionality estimate. We applied our method to 658
 published empirical ecological networks including primary consumption,
 predator–prey, parasitism, pollination, seed dispersal and animal
 dominance networks, to compare with minimum dimensionality estimates when
 the three focal features are missing. Minimum dimensionality was typically
 higher when including alternative interaction modes (54% of empirical
 networks), 'forbidden interactions' as trait-mediated
 interaction outcomes (92%), or a mechanistic perspective (81%), compared
 to estimates missing these features. Additionally, we tested minimum
 dimensionality estimates on simulated networks with known dimensionality.
 Our method typically estimated a higher minimum dimensionality, closer to
 the actual dimensionality, while avoiding the overestimation associated
 with a previous method. Our method can reduce the risk of omitting traits
 involved in different interaction modes, in failure outcomes, or
 mechanistically. More accurate estimates will allow us to parameterise
 models of theoretical networks with more realistic structure at the
 interaction outcome level. Thus, we hope our method can improve
 predictions of community structure and structure-dependent dynamics.
description: Information about the methodology can be found in the
 'README.pdf' file herein, and in the associated article
 published in Methods in Ecology and Evolution.
description: This dataset includes data and code for reproducing the results
 of the associated article on the minimum dimensionality of ecological
 networks. Notes for the usage of the dataset can be found in the
 'README.pdf' file herein.