Friday, August 7, 2009

PS 88-133: Seed rain and phenology in an invasive species removal experiment in Mona Island Reserve, Puerto Rico

Xavier A. Jaime-Davila1, Denny S. Fernandez1, Julissa Rojas2, and Elvia Meléndez-Ackerman3. (1) University of Puerto Rico at Humacao, (2) University of Puerto Rico at Rio Piedras, (3) University of Puerto Rico, Rio Piedras

Background/Question/Methods

As part of an experiment to test the effects of removal of an invasive grass species (Megathyrsus maximus) in cacti and other native plants populations in the Eastern coastal area of Mona Island, we collected seeds and plant parts in tray traps, located in the experimental plots (control, clipping, and total removal of the grass).  Monthly samples were separated and classified in the laboratory; with the exception of seeds that were counted and weighted, other plant parts were oven-dried (60 ºC) for biomass measurement.
Results/Conclusions

First year results show a reduction in seed rain in control plots, independently of the time of the year; treatments affect leaf biomass collection in a more complex way. Removal treatments and time of the year have an effect on reproductive biomass collection, following partially the pattern of monthly precipitation.