PS 103-223
Effects of habitat size and “primatization” on the populations dynamic of a palm tree that is vulnerable of extinction
The hypothesis that reducing the habitat and increasing the abundance of a predator could lead to a negative growth rate of populations of a palm were tested in this study. The objective of this research is to compare long-term dynamics of populations of Euterpe edulis in a fragmented landscape of Atlantic Forest in the state of Rio de Janeiro, Brazil. Populations were marked in 2005, re-sampled in 2006, 2007, 2010, 2011, 2012 and 2013 in four forest fragments (19, 21, 57 and 2,600 ha). The predator (Capuchin monkey, Sapajus nigritus) occurs only in the largest fragment and its population is superabundant. All palm individuals within the plots were marked and measured and re-measured and the new ones were marked and measured. Lefkovitch matrixs were built for each transition year and for each fragment. ʎ and elasticity were calculated.
Results/Conclusions
As a result of these nine years of study, we found variation in population size in small fragments and a linear decrease in the largest fragment. This decrease is mainly due to mortality caused by the predator, which ranged from 10 to 49 adult individuals per year. According to the ʎ 2012-2013, it is estimated that the palm population will decrease 31% in the next year. According to these data, the effect of the overabundance of a predator is most striking in the population dynamics of a species than the reduction of habitat.