DOI: 10.5061/dryad.73520
title: Data from: Removing interactions, rather than species, casts doubt on the high robustness of pollination networks

description: In the last 15 years, a complex networks perspective has been increasingly
 used in the robustness assessment of ecological systems. It is therefore
 crucial to assess the reliability of such tools. Based on the traditional
 simulation of node (species) removal, mutualistic pollination networks are
 considered to be relatively robust because of their 1) truncated power-law
 degree distribution, 2) redundancy in the number of pollinators per plant
 and 3) nested interaction pattern. However, species removal is only one of
 several possible approaches to network robustness assessment. Empirical
 evidence suggests a decline in abundance prior to the extinction of
 interacting species, arguing in favour of an interaction removal-based
 approach (i.e. interaction disruption), as opposed to traditional species
 removal. For simulated networks, these two approaches yield radically
 different conclusions, but no tests are currently available for empirical
 mutualistic networks. This study compared this new robustness evaluation
 approach based on interaction extinction versus the traditional species
 removal approach for 12 alpine and subalpine pollination networks. In
 comparison with species removal, interaction removal produced higher
 robustness in the worst-case extinction scenario but lower robustness in
 the best-case extinction scenario. Our results indicate that: 1) these two
 approaches yield very different conclusions and 2) existing assessments of
 ecological network robustness could be overly optimistic, at least those
 based on a disturbance affecting species at random or beginning with the
 least connected species. Therefore, further empirical study of
 plant–pollinator interactions in disturbed ecosystems is imperative to
 understand how pollination networks are disassembled.
description: Robustness to link
 removal: data and computer codesWe implemented three
 interaction extinction sequences which intended to produce best-, worst-
 and intermediate case scenarios, as has been done in node extinction based
 scenarios. The first sequence always removed the interaction between the
 most connected species (hereafter, most connected first) and its most
 connected mutualistic partner. When more than one species had the same
 degree of connectivity, we randomly chose one of them. This process was
 repeated as many times as the number of interactions in the network until
 the last interaction (the least connected species and its least connected
 mutualistic partner) was removed. . Note that, contrary to NBRA,
 interaction removal did not follow a predefined sequence because the
 degree of species was updated after each interaction extinction. The
 second sequence always removed the interaction between the least connected
 species (hereafter, least connected first) and its least connected
 mutualistic partner, and then continued by removing the remaining
 interactions belonging to the least connected species and its least
 connected mutualistic partner at each iteration step. The third sequence,
 named random, removed interactions at random, to simulate an intermediate
 extinction scenario.Robustness_to_link_removal.rar