In the 1970s, scientists reported that no new generation of Calvaria trees had sprouted in Mauritius in the last couple of centuries. They speculated that without the dodo, the tree seeds no longer germinate. More recent work, however, has located some postdodo saplings. Madagascar appears to be the perfect place to look for a new example of disperser dependence because the island has few fruit-eating mammals and birds, Ganzhorn notes. He has watched animals and collected droppings year-round.
Lemurs seem to be major dispersers, especially the brown lemur.
With the possible exception of the bush pig, it was the only animal that eats and disperses seeds greater than 11 millimeters long. Madagascar's booming human population is wiping out wild habitat. The researchers compared sapling numbers at plots in extended forests with plots in forest fragments where much of the largest wildlife had disappeared. In the fragments without the brown lemur, many fewer saplings of the 20 tree species dependent on lemurs were sprouting than in the larger areas. Saplings from trees dispersed by other animals thrived in both locations.