For my doctoral program at Old Dominion University, I am pursuing advanced study in the field of ecology. My independent research project focuses on a number of research questions pertaining to seed dispersal by frugivorous animals. I conduct my field research in the Dominican Republic, where the interactions between tropical wet forest plants and avian frugivores comprise my study system. My project work takes place primarily on various private cattle farms, and we also cooperate with local Dominican partners in an effort to apply the findings of our research to actual forest and wildlife conservation efforts.
It all started back in 2014, not long after graduating from Saint Olaf College, when I was invited to work as a volunteer with Cornell University’s Josh LaPergola. Josh’s continuing dissertation focuses on the behavioral ecology of the Hispaniolan Woodpecker, whose gregarious nesting behaviors have led him to turn his life upside-down to figure out just what it is about these birds and their environment that has led them to evolve this bizarre reproductive strategy. As chance would have it, these woodpeckers are also prominent dispersers of various native forest plants at our research site. Observing these woodpeckers and another Hispaniolan endemic species, the Palmchat, consume fruits and deliver massive quantities of seeds into cattle pastures eventually led me to develop my graduate research on this system.
For my dissertation, I am broadly interested in three questions regarding avian seed dispersal:
(1) How does variation in reproductive frequency and intensity in fleshy fruit bearing plants affect seed dispersal by frugivorous animals. Does subannual/episodic reproduction in tree species that are capable of fruiting multiple times per year confer adaptive value with regard to interactions with seed dispersers? Do plants receive redundant or complementary seed dispersal by fruiting in multiple seasons?
(2) How do plant and bird diversity and abundance vary across sites characterized by differing intensities of human disturbance, and what might this information tell us about importance of mutualistic interactions in how communities are assembled.
(3)To what extent are frugivorous birds responsible for effective seed dispersal and natural regeneration of forests in pasture landscapes? What actions or creative approaches can be utilized to attract avian seed dispersers to target areas where forest restoration has been initiated or is underway?
The project’s first season in the field began in March 2016. With the aid of small research grants from the Rufford Foundation and the Animal Behavior Society, I recruited the services of two young biologists educated locally at the Instituto Superior de Agricultura (ISA) in Santiago, DR. This year’s efforts focused on the establishment and monitoring of abandoned pasture plots around natural perching structures, monitoring the reproductive phenology of populations of subannual tree species at the site, and radio telemetry to explore whether frugivorous birds may change movement behavior and habitat use between seasons.
Example of a cattle exclosure fence for the pasture abandonment study. This particular plot is below an active Palmchat (Dulus dominicus) colony nest. Seed traps are used to sample the seeds dropped by the birds, and permanent seedling plots are used to monitor the recruitment of bird-dispersed plants.
Guarea guidonia (Meliaceae) is one of the subannually-fruiting plants that I study at my research site. The female plants of this dioecious species flower and fruit multiple times per year in discrete episodes. I am interested in how reproductive investment by these plants and variable fruit production among episodes influences dispersal effectiveness by the frugivore community.
The Hispaniolan Woodpecker (Melanerpes striatus) is the species most frequently observed to consume and disperse Guarea guidonia seeds. Many people unfamiliar with Neotropical avifauna are suprised to learn that woodpeckers tend to be highly frugivorous in these environments. We are currently conducting a pilot study using radio telemetry equipment to triangulate the positions and movements of woodpeckers tagged with VHF transmitters. The goal is to determine to what extent, movement behaviors of this disperser differ between the different seasons when G. guidonia trees are fruiting.
In the 2016 field season, the latest development is my project’s collaboration with Plan Yaque from Jarabacoa. This local NGO, is responsible for the stewardship of the Rio Yaque del Norte watershed. One of their many activities involves work in rural communities to manage degraded streams on which farmers depend for their daily use. On a number of properties, Plan Yaque is attempting to restore riparian forest cover to combat erosion and the drying of streams during periods of draught that have become increasingly more frequent in recent years. I aim to test artificial perch installation as a means of augmenting natural seed dispersal by birds, which may ultimately lead to more speedy recovery of biodiverse successional forests. We will also be capitalizing on this increased availability of study sites to expand observational sampling of plant-bird interactions.
[photos coming soon]