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Effects of population density, sex morph, and tree size on reproduction in a heterodichogamous maple, Acer mono , in a temperate forest of Japan
Author(s) -
Shibata Mitsue,
Kikuchi Satoshi,
Tanaka Hiroshi,
Sueyoshi Masahiro,
Yoshimaru Hiroshi,
Niiyama Kaoru
Publication year - 2009
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-008-0474-4
Subject(s) - biology , pollination , temperate forest , population , pollen , population density , seed predation , reproduction , temperate climate , sex ratio , reproductive success , ecology , population size , maple , botany , demography , seed dispersal , biological dispersal , sociology
The effects of local population density, sex morph [protogynous (PG) or protandrous (PA)], and individual tree size on the demographic processes of seed production were investigated in a heterodichogamous maple, Acer mono Maxim. var. Marmoratum (Nichols.) Hara f. dissectum , in a temperate forest of Japan. As the distance from conspecific reproductive adults increased, the percentage of immature seed fall and empty seeds increased significantly, indicating higher pollination success along with local population density. Although the difference was not distinct, pollination success was affected by the local population density of the reciprocal sex morph rather than that of both sex morphs. The trees at higher local population density sites suffered higher seed mortality due to predation and decay, and tended to produce smaller seeds. Thus, the impacts of local population density operated both positively and negatively on reproduction. As a factor of individual traits, tree size scarcely affected any demographic processes. On the other hand, sex morph did affect pollination success. Trees of PG type had lower immature seed fall than those of PA type, suggesting that the former has higher efficiency of pollen acceptance than the latter. The results on seed demography presented here partly support previous suggestions that heterodichogamous plants exhibit reciprocal cross‐pollination and gender specialization as reproductive traits.