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Fragoso
José M. V. Fragoso, Ph.D.
Senior Scientist
Biology Department

Stanford University, USA


 


Personal Research Statement

I began my research career in the Neotropics as an undergraduate student, when I spent eight months in Belize independently studying the biology and ecology of the Central America tapir for my honors thesis. An extensive literature search had revealed that little was known about this animal in the wild, despite its large size, potential as an ecological driver and importance as a game animal. Realizing that this was true for most large vertebrate species of the Neotropics, and reasoning that synthetic and theoretical ecology in the tropics would require basic ecological information on these potential keystone species, I focused my graduate and post-doctoral studies on the ecology of large Neotropical vertebrates.

My early studies of the Central American tapir suggested that large vertebrates played a major role in structuring tropical ecosystems. For my PhD thesis I therefore decided to examine how tapirs, white-lipped peccaries, collared peccaries and other animal species interacted to influence the diversity, organization and structure of an Amazonian forest through seed dispersal and seed and seedling predation, with a particular focus on the home range and scale of movement of these animals relative to the distribution of clustered tree species and patchy habitats. I eventually integrated the influence of seed-eating insects in the system and began to consider how organisms acting at different trophic levels could influence ecological and evolutionary outcomes.

My PhD thesis and a series of subsequent studies noted how interactions between tapirs, peccaries, rodents, primates, ants, bruchid beetles and palms generated distribution and abundance patterns for all species, and influenced ecological and evolutionary patterns. Two unplanned events helped to guide this landscape scale focus. First, while radio-tracking white-lipped peccaries, my funding was insufficient to allow me to rent occasional airplane time, because an ongoing gold-rush in northern Brazil put airplane and fuel prices out of the reach of my graduate student budget. I therefore purchased an experimental two-seater ultralight airplane, and learned how to pilot it. During the four years that I flew on a regular basis over undisturbed tropical forest, I was able to closely observe and map at a meso-scale level (the spatial scale at which the animals moved) the distribution pattern of several tree species.

At the end of these field studies, I was fortunate to spend two years as a post-doctoral associate in the lab of C. S. Holling at the University of Florida, where the lab’s focus on hierarchies of spatio-temporal process and clustered distributions of organisms and processes in space and time resonated with my empirical observations of the distributions and population cycles of tropical plant and animal populations. In consequence, my collaborators, graduate students and I identified long-distance (more than 1 km from the parent tree) seed dispersal as a key factor influencing seed escape from insect predators. When summed to the documentation of long-distance seed and seedling predation processes by white-lipped peccaries, this contributed to a shift in focus from small-scale Janzen-Connell dynamics to the landscape scale distribution of safe sites for seedling establishment. Empirical, experimental demonstrations of the importance of long-distance seed dispersal resulted in the elaboration of a model that posits the gradual, element-by-element shift of plant-vertebrate-invertebrate associations across the landscape. My students and I continue to add new animal species and interactions to this system, and are currently asking how population reduction, species removal (extinction) or species addition (introduction) through anthropogenic effects influence forest regeneration and community structure.

I am also interested in how these interactions influence the evolution of animal and plant traits, including herding behavior in peccaries and fruit structure in palms. My collaborators and I have described the way in which fruits parts and seed number may have evolved in Attalea palms in response to opposing predation pressures from vertebrate dispersers and vertebrate and invertebrate predators.

In the tropics, hunting, habitat degradation, and habitat fragmentation by humans are major drivers of changes in animal and plant distribution and abundance patterns. The synergy between habitat modification and climate change is also an increasing concern in the region. I am deeply interested the development of effective wildlife management strategies and policies for the tropics. This line of applied research includes working with indigenous and non-indigenous rural peoples throughout the Neotropics to understand culturally influenced approaches to resource management, and the valuation of and attitudes towards wildlife resources. Although disciplinary work in ecology is often necessary to understand the dynamics of the wildlife populations of concern, these studies serve as subsidies to a broader coupled natural human system perspective that focuses on the ways in which human and non-human nature shape each other in these hunting based systems.
   

 

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