Examining Natural Seed Dispersal Interactions in the Caribbean Archipelagos and Their Status in the Anthropocene

Plant-animal mutualisms, particularly frugivory, influence ecosystems by playing key roles in plant and animal life histories. These interactions are threatened by disturbances like defaunation and the proliferation of invasive species. Given these risks, it is important to assess their status to define conservation priorities and the abilities of species to adapt when facing threats. Here, I researched plant-frugivore interactions in the Caribbean archipelagos, an understudied biological hotspot. My goal is to expand our understanding of frugivory, and how anthropogenic effects shape this important process. To do so, I 1) investigated spatial associations between frugivore and plant distributions, 2) evaluated the loss of frugivory function due to declining large animal populations and determined its effects on germination, 3) assessed how frugivory dynamics react to non-native mammals, and 4) explored an alternative, abiotic dispersal method that plants may use in the absence of frugivore partners. I used multiple methods including spatial analysis, germination trials, field assessments, and movement modeling in this pursuit. I found that plant-frugivore relationships are threatened in the region, with common frugivores having many times smaller ability to interact with fruits than threatened reptiles. Meanwhile higher non-native mammal activity was associated with significant declines in native frugivory interactions. Given that I found links between frugivorous animal and fruiting plant distributions, the erosion of plant-frugivore interactions bodes poorly for plants and the animals that depend on them. Fortunately, my results indicate that successful restoration and conservation of Caribbean megafauna populations could re-establish eroded interactions. Furthermore, I find evidence that some fruiting species benefit from dispersing across the region through ocean-currents. Overall, I demonstrate the importance of maintaining healthy mutualistic interactions and lay the foundation for future conservation and research efforts.