Document: EMI-3-37-1

Forest fragmentation and the population dynamics of an Amazonian herb.

BRUNA, E.M.*

University of California-Davis ¹

Abstract:
Heliconia acuminata is an understory herb found in both the rainforest fragments and the continuous forest reserves of Brazil's Biological Dynamics of Forest Fragments Project. I marked and measured over 4000 individuals of H. acuminata in both fragments and forest and recorded their fecundity, growth, and survivorship over the course of two years. I then combined these demographic data with experimental results on seed germination and seedling survivorship into a six-stage matrix demographic model. This model was used to calculate population growth rate (lambda) in fragments and forests and predict short-term population dynamics. Flowering and seed germination success were significantly lower in forest fragments than continuous forest, while adult survivorship was high in all sites. In addition, growth rate lambda was less than one in all forest fragments and greater than one in five of six continuous forest sites. Although there is almost certainly year to year variation in lambda, these results suggest that long term reduction in reproduction and growth rates could lead to local extinction of H. acuminata from forest fragments.

Keywords: fragmentation, plant demography, Heliconia

This abstract is being presented at: 2:45 PM in session:
Oral Session #33: Plant Demography.