Megaherbivores as pacemakers of carnivore diversity and biomass: distributing or sinking trophic energy?

Abstract

Question: What is the trophic role of megaherbivores? Hypothesis: Depending on their life histories, megaherbivores can either act as sinks or distributors of trophic energy. Methods: Comparative review of mammal and dinosaur faunas, and aspects of their reproductive biology. Conclusion: Extant (mammalian) megaherbivore populations represent trophic sinks that potentially limit carnivore diversity and productivity, because they are immune to predation and follow a reproductive strategy of very few, well-protected offspring. In contrast, in dinosaur faunas, particularities of reproductive biology such as a larger number of offspring and limited parental care made a major part of megaherbivore biomass available to carnivores. This increase in available trophic energy in consequence allowed for larger body masses and higher species diversity of dinosaur carnivores.