A flash in the pan? The population dynamics of a dominant pioneer
species in tropical dry forest succession
Abstract
Globally, around half of all tropical forests are secondary communities
which are recovering from previous disturbances. In these communities,
dominant pioneers play a critical role in the successional dynamics due
their ability to modify the environment, and thus to facilitate or
hinder the performance of other species. In this study, we examined the
population dynamics of the dominant pioneer species, Mimosa
acantholoba var. eurycarpa, in a tropical dry forest during the
process of secondary succession. We collected data from permanent plots
over a period of 13 years and used integral projection models to analyze
the vital rates and changes in population size. Most vital rates were
negatively related to successional age, with resprouting, survival and
recruitment of individuals responding more strongly, and individual
growth rate more weakly. These vital-rate trends translated into
significant variation of population size over succession, with a maximum
size at year four and a rapid decline thereafter. Overall, our findings
suggest that this species benefits from its ability to display a large
number of resprouts in very early stages of succession, contributing to
the rapid increase in population density. However, as succession
unfolds, a lack of resprouting and a decline in survival reduce its
population size, to the point of local extinction. These results
highlight the importance of resprouting in the early dynamics of
tropical dry forest communities recovering from disturbance.