RT Journal Article
T1 Influence of continental history on the ecological specialization andmacroevolutionary processes in the mammalian assemblage ofSouth America: Differences between small and large mammals
A1 Moreno Bofarull, Ana
A1 Arias Royo, Antón
A1 Hernández Fernández, Manuel
A1 Ortiz Jaureguizar, Edgardo
A1 Morales Romero, Jorge
AB Background: This paper tests Vrba's resource-use hypothesis, which predicts that generalistspecies have lower specialization and extinction rates than specialists, using the 879 species ofSouth American mammals. We tested several predictions about this hypothesis using the biomicspecialization index (BSI) for each species, which is based on its geographical range within differentclimate-zones. The four predictions tested are: (1) there is a high frequency of species restrictedto a single biome, which henceforth are referred to as stenobiomic species, (2) certain clades aremore stenobiomic than others, (3) there is a higher proportion of biomic specialists in biomes thatunderwent through major expansion-contraction alternation due to the glacial-interglacial cycles,(4) certain combinations of inhabited biomes occur more frequently among species than do others.Results: Our results are consistent with these predictions. (1) We found that 42 % of the speciesinhabit only one biome. (2) There are more generalists among species of Carnivora than in cladesof herbivores. However, Artiodactyla, shows a distribution along the specialization gradientdifferent from the one expected. (3) Biomic specialists are predominant in tropical rainforest anddesert biomes. Nevertheless, we found some differences between small and large mammals inrelation to these results. Stenobiomic species of micromammalian clades are more abundant inmost biomes than expected by chance, while in the case of macromammalian clades stenobiomicspecies are more frequent than expected in tropical rainforest, tropical deciduous woodland anddesert biomes only. (4) The most frequent combinations of inhabited biomes among the SouthAmerican mammals are those with few biomes, i.e., the ones that suffered a higher rate ofvicariance due to climatic cycles.Conclusion: Our results agree with the resource-use hypothesis and, therefore, with a major roleof the past climatic changes as drivers of mammalian evolution. Nevertheless, deviations from theexpectations indicate the importance of differences in reproductive traits and paleobiogeographichistory for the macroevolutionary processes involved. In the case of South American mammals, thePliocene Great American Biotic Interchange strongly influences the ecological characteristics of thisassemblage. Furthermore, the Andes have acted as a fertile ground for speciation in environmentsprone to vicariance. Finally, the micromammals appear as more prone to biomic specialization thanlarger species. These factors are responsible for some of the differences found between SouthAmerica and Africa in the studied pattern. For example, the extensive South American mountainranges favour a higher number of combinations of inhabited biomes in comparison with Africa.
PB BioMed Central
SN 1471-2148
YR 2008
FD 2008-03-26
LK https://hdl.handle.net/20.500.14352/49566
UL https://hdl.handle.net/20.500.14352/49566
LA eng
DS Docta Complutense
RD 10 abr 2025