Elise Sivault, Kim R. McConkey, François Bretagnolle, Asmita Sengupta, Joanna Lambert, Eckhard W. Heymann, Anthony Herrel, Pierre-Michel Forget
This is a plain language summary of a Functional Ecology research article which can be found here.
Many trees depend on mammals for seed dispersal, especially in the tropics. Indeed, mammals can consume many fruits and ingest many seeds that can be found, sometimes, perfectly intact in their scat. As the deposition of seeds away from the parent tree promotes seedling survival, mammals have an essential role in the regeneration of many tree species—especially the species that have large seeds because of their limited passive dispersal abilities. However, most large mammals are threatened in the tropics. Thus, it is essential to understand the relationships between the morphology of a mammal such as its skull dimensions or body mass, and the size of the ingested fruits and seeds. This would then allow us to make estimations on the dispersal limitations that the tree species would undergo if those mammals disappeared.
We measured skulls and compiled body mass, seed, and fruit size data from the literature for bats, carnivores (e.g., kinkajou), and primates from Africa, South America, Asia, and Madagascar, all recognized as important dispersers and having a high consumption of fruit in their diet.
Our results demonstrated a link between seed size, skull dimensions, and body mass in frugivorous mammals. Nevertheless, body mass generated stronger relationships with both the average and maximum seed sizes than skull dimensions. Based on these results we estimated the ingestion abilities of five extinct monkeys (i.e., three lemurs, one titi monkey and one howler monkey) based on their body mass and skull dimensions. These monkeys likely played significant roles in the seed dispersal of large-seeded plant species (seeds up to 3 cm long) in tropical forests in the past. Our study provides, therefore, a strong basis for predicting the consequences of frugivore extinction within tropical forests.