Amazonian fragmentation

Habitat fragmentation is a pervasive and ongoing global phenomenon. Habitat fragmentation can cause a cascade of abiotic and biotic changes in the habitat that remains. Implications for populations that survive the initial disturbance are numerous and complex.

It has been shown that habitat fragmentation negatively affects plants growing in remnant forests, but the specific underlying demographic mechanisms are less known. I have most recently begun searching for these mechanisms using a decade-long dataset of an understory plant (Heliconia acuminata Rich.) from fragmented Amazonian forests. It is well established that fragmentation reduces survivorship and reproduction in plants living in forest remnants. My efforts have demonstrated that forest fragmentation also changes long-term growth rates in the focal plants; these smaller, slower growing plants in fragments in turn have lower rates of survival and reproduction (Gagnon et al. 2011).

I am now exploring a series of additional demography-related questions for plants in forest understories using stochastic matrix models. Examples include: to what extent does species demography vary among sites in tropical forest habitat; how does habitat fragmentation alter the influence of different vital rates on population growth rates; and how does habitat fragmentation alter projected growth of populations in stochastic environments?