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Differences in growth trajectory and strategy of two sympatric congeneric species in an Indonesian floodplain forest
Author(s) -
Yamada Toshihiro,
Ngakan Oka Putu,
Suzuki Eizi
Publication year - 2005
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.92.1.45
Subject(s) - biology , sympatric speciation , context (archaeology) , understory , biomass (ecology) , floodplain , shade tolerance , botany , ecology , canopy , paleontology
Whole‐plant development trajectories and sapling leaf displays were compared for two sympatric congeneric species, Pterospermum diversifolium and P. javanicum , in a tropical floodplain forest in East Kalimantan, Indonesia. We assessed their growth strategies and developed hypotheses for their coexistence within the community. Pterospermum diversifolium retains a monoaxial growth habit that promotes quick stem elongation; thus, it is taller when branches are initiated than is P. javanicum . The species differed significantly in height growth and total crown expansion per unit increment of biomass: monoaxial P. diversifolium saplings devote more effort to stem elongation, whereas branched P. javanicum saplings devote more effort to branch expansion. Monoaxial P. diversifolium sustained more severe self‐shading than P. javanicum . The sapling growth strategy of P. diversifolium appears to be dynamic, emphasizing the opportunistic use of light following a disturbance, whereas that of P. javanicum appears to be static, optimizing leaf display for current light conditions. The advantages of these strategies depend on context, and the two species may coexist within a community by adopting different regeneration niches based on differing understory light conditions: P. diversifolium is favored over P. javanicum at high light levels, but the opposite is true at low light levels.