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CONSEQUENCES OF VARIABLE REPRODUCTION FOR SEEDLING RECRUITMENT IN THREE NEOTROPICAL TREE SPECIES
Author(s) -
De Steven Diane,
Wright S. Joseph
Publication year - 2002
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2002)083[2315:covrfs]2.0.co;2
Subject(s) - ecology , reproduction , seedling , biology , tree (set theory) , botany , mathematics , mathematical analysis
Variable seed production may have important consequences for recruitment but is poorly documented for frugivore‐dispersed tropical trees. Recruitment limitation may also be a critical spatial process affecting forest dynamics, but it is rarely assessed at the scale of individual trees. Over an 11‐yr period, we studied the consequences of variable seed production for initial seedling recruitment in three shade‐tolerant tree species ( Quararibea asterolepis , Tetragastris panamensis , and Trichilia tuberculata ) on Barro Colorado Island, Panama. We measured annual seed production for a permanent sample of focal trees and censused annual new seedling establishment within a restricted dispersal neighborhood of each tree. We analyzed temporal and spatial variability in recruitment and compared recruitment limitations among species. Annual seed production in Quararibea and Tetragastris fluctuated widely, whereas Trichilia had more consistent seed production across years. Within species, trees were synchronized in seed production, and synchrony appeared partly influenced by El Niño climatic events. Seedling recruitment varied temporally and spatially. At the population scale, all species had greater recruitment in productive seed years, and individual trees had differing contributions to this temporal pattern. At the focal‐tree scale, recruitment patterns differed among species. Quararibea and Tetragastris trees with higher average seed production recruited more seedlings in their local neighborhoods than did less fecund trees. In contrast, Trichilia seedling recruitment did not increase with seed crop size, suggesting negative density dependence. At the tree neighborhood scale, no species showed evidence of density dependence in first‐year survival. Comparatively, recruitment was more seed‐limited in Quararibea and Tetragastris and more establishment‐limited in Trichilia . Overall, our results indicated that: (1) variable seed production influenced seedling recruitment both temporally and spatially, and (2) species differed in limitations to recruitment.