Megafauna fruits have much larger seeds that non-megafauna fruit of the same size. What is the value of large fruits? They have larger seedlings, can establish in less favourable habitats, can survive being partially eating.
How did these trees survive 10,000 years without megafauna?
He describes his research site in the Brazilian pantanal, include exotic megafauna like livestock and feral pigs. Collected lots of dung and scats and looked for fruiting, and also did camera trapping to same who came to feed on these fruits. They show that agoutis can also disperse a lot of megafaunal fruits.
At least 25% of megafaunal fruit can resprout and reproduce vegetatively
Many megafaunal fruits are dispersed by humans (e.g cacao). The dominant dispersers were first megafauna, then pre-Colombian humans, then fire and exotic megafauna. A succession of dispersers
Megafauna gut retention time is a function of body mass. They are using this to model seed dispersal kernels to simulate seed dispersal. He compares the Pleistocene dispersal kernel with that of the Holocene (where it is dominated by tapirs). The dispersal kernel did drop but not hugely (by a factor of about 1.6)
What are the consequences of reducing dispersal distance. The extinction of megafauna dispersers means that gene flow is occurring mainly by pollen movement (Collevatti et al. 2003 Molecular Ecology). They are compiling genetic differentiation of megafauna fruits with other zoochoric fruits. We can detect the “megafauna footprint” in the genetic structure of plants.
Yadvinder: there is some debate as to whether megafauna were abundant within the Amazon forest biome, as opposed to in the savanna. He has not studied this specifically but he things that megafaunal fruit will be abundant in the rainforest.
Adam Wolf: are there any long-term consequences because of the genetic shifts?
No evidence of any megafaunal dispersed seeds having gone extinct. Humans played a major role in their dispersal..