Modeling the Population Demographics & Viability of Imperiled Guzmania monostachia Populations

Abstract

Guzmania monostachia is a large, long-lived bromeliad whose leaves grow in a rosette pattern and is native to the Americas, but endangered in Florida due to damage caused by the invasive weevil Metamasius callizona. Each G. monostachia rosette can reproduce sexually via flowers or asexually by producing clonal offshoot rosettes. We model the population dynamics and demographic structure of a G. monostachia population using a Lefkovitch matrix model where each state represents a demographic class of rosettes. Model analysis over a range of uncertain parameters show the conditions under which a G. monostachia population is viable in the absence and presence of M. callizona, and the expected demographic structure under those conditions. In particular, our analysis illustrates that proportional reductions in survival have a qualitatively stronger impact on population viability than proportion reductions in clonal fecundity.