Because of their large size, the Baird’s tapir (Tapirus bairdii) is one of the few species capable of dispersing large seeded trees, such as the ecologically important Manilkara zapota (zapote). We hypothesized that tapir modify their movements in response to acute water shortage brought about by long-term declines in precipitation. We conducted a large scale field experiment in the forest of the Southern Yucatan Peninsula to evaluate: 1) does the tapir facilitate zapote seed germination, survival and growth, 2) does seed germination depend upon site deposition as mediated by the tapir. In a fully factorial design, 1920 zapote seeds collected from tapir dung and ripe fruits were planted in either tapir dung or soil. Replicate, caged, germination stations were placed in monodominant zapote stands and seasonal waterholes (habitat commonly frequented by tapir).
Initial results show contrary to previous expectations, that tapirs act as seed dispersers of zapote. Zapote germination was low (<30%), especially around water holes. We observed no significant effects of seed source or substrate upon seed germination probability. Current analyses are assessing the effects of tapir on seedling survival and growth. We will use movement data to create a model of zapote recruitment and regeneration under future scenarios of climate change and forest fragmentation.
