Central Argentina vegetation characteristics linked to extinct megafauna and some implications on human populations

RINDEL, DIEGO D; MOSCARDI, BRUNO F; COBOS, VIRGINIA A; GORDÓN, FLORENCIA

HOLOCENE (SEVENOAKS)

SAGE PUBLICATIONS LTD

Año: 2024

0959-6836

In this paper we study the relationships between plants and extinct megafauna by examining the characteristics of the vegetation in the central regionof Argentina (i.e. Espinal, Monte, and Chaco phytogeographic regions). First, we study the size, shape, quantity, and characteristics of fruits and seeds.We also evaluate the presence of mechanical (spinescence and wood density) and chemical (secondary metabolic compounds) defenses against highrates of herbivory. Complementarily, we assess the importance these plants had for human populations, using archeological, ethnographic, and currentdata. A high percentage of the analyzed plants met the criteria proposed for fruits and seeds dispersed by megafauna, together with a high frequencyof spinescence, high density woods, and secondary metabolites. We propose that these traits cannot be explained by the herbivory pressure of extantfauna in the area, but rather developed in interaction with currently extinct fauna. We suggest that Pleistocene megafaunal extinction had importantconsequences in the region due to their role as ecosystem engineers and to vegetation’s characteristics, which were probably strongly shaped bymegafauna activities. Among these consequences, we discuss the loss of certain interactions between these animals and vegetation, such as loss of seeddispersal mechanisms, shrub invasion, and increased susceptibility of vegetation to fire. Other effects for hunter-gatherer groups were the generation ofhighly regulated mobility patterns and the formation of barriers for the dispersal of prey. Finally, we also discuss the importance of these plants for humanpopulations as food, construction material, medicines and firewood. Likewise, the role of humans as “heirs” of the megafauna in the propagation of treeand shrub species is highlighted.