Functional grouping is an extremely useful technique for simplifying and understanding ecosystem processes of a wide range of organisms within a certain trophic role. The methodology from a previous study on large African herbivores for functional grouping on a continental scale served as the basis of this study in South American terrestrial herbivore functional grouping. The characteristics chosen for functional grouping were: body weight, diet, sociality, water dependence and gut type. These were compiled from an extensive literature search for 42 South American terrestrial herbivorous mammals. The correlation between species and functional characteristics were analyzed using principle component analysis (PCA) and the functional groups were clustered using hierarchical clustering principle components (HCPC). Both statistical analyses were conducted with the FactoMineR package in R program.
Results/Conclusions
Six functional groups resulted from the species-level analyses: water dependent browser/frugivores (Cuniculus, Pudu), small ruminant browsers (Mazama, Odocoileus), large ruminant grazers (Blastocerus, Ozotocerus, Vicugna, Lama, Hippocamelus), social non-ruminant grazers (Hydrochoerus, Dolichotis), large non-ruminant browser/frugivores (Tapirus, Pecari, Tayassu, Catagonus), and small solitary frugivores (Dasyprocta). Two highly speciated genera (Dasyprocta and Mazama) were so prominent that they skewed the clustering in favor of groups composed almost entirely of species within their genus. Therefore, the analyses were run at genus level. The five resulting functional groups included social omnivores (Pecari, Tayassu, Catagonus), non-ruminant grazers (Dolichotis, Hydrochoerus), ruminant grazers (Vicugna, Blastocerus, Lama, Hippocamelus), small solitary browser/frugivores (Pudu, Cuniculus, Dasyprocta, Mazama) and large solitary water dependents. (Blastocerus, Tapirus). At genus level, Mazama and Dasyprocta were not so domineering and were grouped together in the “small solitary browser/frugivores”. Another significant change in the genus analysis was the emergence of a group made up exclusively of the peccary genera. Results showed that a significant portion of functional groups of South American herbivores are characterized by a frugivore/browser diet, which might be a result of the more forested nature of the South American continent, as well as indicate the crucial role that seed dispersers play in these ecosystems. In addition, the study revealed the shared roles of ungulates and rodents in many functional groups, and gives a clear example of how South America’s evolutionary history has led to diversity in its fauna composition, yet a convergence of ecological functions.