Revista Chilena de Historia Natural 76 (4): 639-650, 2003
RESEARCH ARTICLE
Influence of overstorey species identity on resource availability and variation in composition of
advanced regeneration in a temperate rainforest in southern Chile
Understory habitat heterogeneity is believed to be a factor promoting maintenance of
species diversity in forest communities. The influence of over storey species identity on resource availability and variation in
composition of advanced regeneration was studied in a temperate rain forest in southern Chile. The forest overstorey was dominated
by the broadleaved evergreens Laureliopsis philippiana, Aextoxicon punctatum, Eucryphia
cordifolia and Nothofagus dombeyi. Availabilities of diffuse light, nitrogen, phosphorous and calcium were measured
under these four over storey species, as was nutrient content of leaf litter. Advanced regeneration was sampled in plots beneath each
over storey species, and results analyzed by ordination. There were significant differences in light transmission, nutritional content of
leaf litter and availability of N-NO<sub>3</sub> and P beneath the four species. Nevertheless, all nutrients showed low
availability due to low mineralization and high immobilization. Ordination results indicate that the composition of advanced regeneration
under N. dombeyi and L. philippiana differed from the composition of regeneration under A. punctatum
or E. cordifolia. The ordination suggested that light level explained a large proportion of compositional variation. We
propose that species regenerating in the understory differed more in shade tolerance than in nutritional requirements, light being the
most limiting resource in the understorey.
Key words:
evergreen forest,
advanced growth composition, mineralization, light gradient
