Differences in allometry and population structure between native and invasive populations of a tropical tree

Abstract

Introduced species can establish self-replacing populations in introduction sites despite climatic differences between these sites and the native range. Schizolobium parahyba (Fabaceae) is a fast-growing tree from the Atlantic Forest in Brazil and is invasive in semideciduous forests. We studied the allometry and population structure of S. parahyba within its native and invaded ranges. We expected to find differences in allometric relationships and ontogenetic stage sizes between forest types. We measured individuals within native and invaded ranges and analysed height : diameter allometry using standardised major axis regression. We used the chi-squared test and permutational multivariate analysis of variance to compare the frequencies of individuals of each ontogenetic stage between native and invasive populations. We found that allometry differed between forest types for seedlings, but only marginally for adults. The population structure differed between ranges and suggests active recruitment of juvenile and subadult plants in invaded sites, where the species is naturalising.