Differences in survivorship between species reflected the interaction between

likelihood of damage and the ability to tolerate damage-induced stress. Contrary to my

expectation shade-tolerant species with stronger material properties (i.e., tougher stems

and higher stem tissue density), did not differ from species with weaker material

properties in the probability of suffering mechanical damage, but once damaged they

were less likely to die than species with weaker stems (Table 2-2). Contrary to this

pattern, A.cruenta, a shade-tolerant species with weak stems (Chapter 1), was the least

likely to die after suffering mechanical damage, suggesting that other factors, such as

carbohydrate storage reserves in stems and roots play an important role in the ability of

seedlings to tolerate mechanical damage (Myers 2005). Additionally, the probability of

survival after being damaged (measured as damage fatality) was different depending on

the type of damage received. For example, seedlings that were uprooted or had broken

stems usually died, while seedlings that suffered leaf damage or bent stems were more

likely to survive. My results (and previous studies, Marquis & Braker 1994) suggest that

leaf damage (caused by leaf herbivory) constitutes a less severe stress than stem bending

and breakage.

 Numerous studies have emphasized the benefits of having a large seed, resulting in

a large seedling and increased survival (Paz & Martinez- Ramos 2003, Green & Juniper

2004, Moles & Westoby 2004b). In contrast, in my study there was no correlation

between seed size and seedling survival, susceptibility to damage agents, or incidence of

different types of damage (Table 1-4). One possible reason is that on BCI large seeded

species face strong pressures from vertebrate cotyledon predators. Barro Colorado Island,

due to the absence of top predators, supports high densities of medium sized mammals