A Probabilistic View of Forbidden Links: Their Prevalence and Their Consequences for the Robustness of Plant–Hummingbird Communities

• Published in: Ecology letters Vol. 28; no. 1; pp. e70073 - n/a
• Main Authors: Duchenne, François, Barreto, Elisa, Guevara, Esteban A., Beck, Holger, Bello, Carolina, Bobato, Rafaela, Bôlla, Daniela, Brenes, Emanuel, Büttner, Nicole, Caron, Ana P., Chaves‐Elizondo, Nelson, Gavilanes, María J., Restrepo‐González, Alejandro, Castro, Jose Alejandro, Kaehler, Miriam, Machado‐de‐Souza, Tiago, Machnicki‐Reis, Miguel, Marcayata, Andrés Sebastián F., Menezes, Cauã G., Nieto, Andrea, Oliveira, Rafael, Oliveira, Ricardo A. C., Richter, Friederike, Rojas, Bryan G., Romanowski, Luciele L., Souza, Wellinton L., Veluza, Danila S., Weinstein, Ben, Wüest, Rafael O., Zanata, Thais B., Zuniga, Krystal, Maglianesi, María A., Santander, Tatiana, Varassin, Isabela G., Graham, Catherine H.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.01.2025
• Subjects: Animals; Bayes Theorem; Bayesian analysis; Bayesian theory; Birds - physiology; data collection; ecology; Ecosystem; Exploitation; exploitation barrier; extinction; Flowers - physiology; forbidden link; linkage rule; Links; Models, Biological; mutualism; Plants; Rare species; Robustness; sparsity; species; Species extinction; stability; trait matching; trait matching; forbidden link; linkage rule; sparsity; exploitation barrier; stability; mutualism
• ISSN: 1461-023X; 1461-0248; 1461-0248
• DOI: 10.1111/ele.70073

ABSTRACT The presence in ecological communities of unfeasible species interactions, termed forbidden links, due to physiological or morphological exploitation barriers has been long debated, but little direct evidence has been found. Forbidden links are likely to make ecological communities less robust to species extinctions, stressing the need to assess their prevalence. Here, we used a dataset of plant–hummingbird interactions, coupled with a Bayesian hierarchical model, to assess the importance of exploitation barriers in determining species interactions. We found evidence for exploitation barriers between flowers and hummingbirds across the 32 studied communities; however, the proportion of forbidden links changed drastically among communities because of changes in trait distributions. The higher the proportion of forbidden links, the more they decreased network robustness because of constraints on interaction rewiring. Our results suggest that exploitation barriers are not rare in plant–hummingbird communities and have the potential to limit the rescue of species experiencing partner extinction. Analysing 32 plant–hummingbird communities, we found evidence for forbidden links in all of them, with a proportion varying from 3% to 29% of the possible interactions. Where they were in high proportion (> 15%), forbidden links decreased substantially the robustness to extinctions because of constraints on interaction rewiring. Our results suggest that forbidden links are not rare in plant–hummingbird communities and have the potential to limit the rescue of species experiencing partner extinction.