Population ecology of Euterpe edulis Mart. (Palmae).
1- The ecology of a population of the tropical palm tree Euterpe edulis Mart. was studied at
the Municipal Reserve of Santa Genebra, Campinas (Sao Paulo, Brazil). This palm has
been intensively exploited due to the quality of its heart of palm (palmito). The heart of
palm corresponds to the apical meristem of the plant together with the developing new
2- The indiscriminate exploitation that this palm has been subject to over recent years in
southern Sao Paulo may result in it becoming extinct in many forest fragments. The
biodiversity of large animals in these forests has declined as a consequence of hunting,
and the overexploitation of E. edulis has also led to a decline in the number of large
frugiverous birds. The financial benefits generated by the sustainable exploitation of
palmito can exceed those from a single extraction or those from forest conversion to
3- The seed and seedling ecology of the population of E. edulis was examined. On average
each plant produced approximately 1500 fruits and, there was a tendency for plants of
intennediate size to be slightly more fecund. Most seeds were found in close proximity to
adult plants; the distance of dispersal could be described by a negative power curve. Five
species of birds belonging to the Family Turdidae were observed to feed on the fruits of E.
edulis while on the tree, while subsequent dispersal along the gro':lnd was found to occur
by water. The probability of surviving and growing to the next Sl~ class was inversely
related to the number of seedlings. The maximum survival of seedlIngs and growth to the
next size class occurred approximately 4 m from adult plants, indicating that the survival
and growth of seedlings was suppressed in the immediate vicinity of conspecific adults.
4- The spatial pattern of the population of E. edulis, in the Municipal Reserve of Santa
Genebra, was significantly clumped. The data indicate that the spatial distribution of
individuals becomes less clumped with time as individuals develop.
5- The transition matrix analysis of the population revealed that the population is
increasing at a rate of 14% year-I. The highest sensitivity was observed in the transition
from size-class 1 (0-10 mm diameter) to class 2 (10.1 - 20 mm). According to the
elasticity analysis, most of the value of the finite rate of population increase is accounted
for by the probability of surviving and remaining in the same size class. The results from
the haryesting simulations, indicate that it is possible to harvest E. edulis sustainably when
harvesting is restricted to size class 6 plants (Le. reproductive adults).
6- The density-dependence observed for survival and growth of plants in the smallest size
class was s~ong enough to affect the population dynamics of E. edulis. Elasticity analysis
of the transItion matrix shows that the position of populations of E. edulis in G-L-F space
moves towards the L apex of the demographic triangle as the density of plants increases.