Ecological Archives E095-298-A3

Mariana M. Vidal, Erica Hasui, Marco A. Pizo, Jorge Y. Tamashiro, Wesley R. Silva, Paulo R. Guimarães Jr.. 2014. Frugivores at higher risk of extinction are the key elements of a mutualistic network. Ecology 95:3440–3447. http://dx.doi.org/10.1890/13-1584.1

Appendix C. Results obtained from other classifications of bird sensitivity to human disturbances, based on Stotz et al. 1996.

Along with the IUCN assessment of extinction risk, we classified all bird species by their sensitivity to human disturbances according to Stotz et al. (1996). The authors assigned each tropical bird species a qualitative assessment of sensitivity to human disturbances (high, medium or low) based on their field experience and knowledge on the natural history of birds. We explored the relationship between bird sensitivity to human disturbances and species contribution to network organization by performing two-sample randomization tests (Manly 1997), comparing the three categories of bird sensitivity pairwise (high × medium; high × low; and medium × low). For each pair of categories, we randomized the values of species contribution to network organization among the levels of sensitivity to human disturbances (1000 replicates).

Bird species' sensitivity to anthropogenic disturbances affects their contributions to network organization. In general, species that contribute more to network organization are significantly more vulnerable to human disturbances (Fig. C1; high × medium: P = 0.008; high × low: P = 0.024). For instance, three of the four species that contribute most to network organization – Carpornis cucullata, Lipaugus lanioides and Pteroglossus bailloni – are highly sensitive to anthropogenic disturbances (Stotz et al. 1996, Fig. C2).

 

FigC1

Fig. C1. Variation in species contribution to network organization (mean ± SE) across levels of sensitivity to human disturbances.


 

FigC2

Fig. C2. Bird species' contributions to the organization of the network of interactions between plants and frugivorous birds at an Atlantic-forest site. The species are arranged in decreasing order by their contribution to network organization. The asterisk highlights a species identified only to the genus level for which we were not able to classify its degree of sensitivity to human disturbances.


 

Literature Cited

Manly, B. F. J. 1997. Randomization, Bootstrap and Monte Carlo Methods in Biology. Second edition. Chapman & Hall/CRC, London, UK.

Stotz, D. F., J. W. Fitzpatrick, T. A. Parker III, and D. K. Moskovits. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago, Illinois, USA.


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