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DISPERSAL OF SEEDS BY THE TROPICAL SEA BREEZE
Author(s) -
Greene D. F.,
Quesada M.,
Calogeropoulos C.
Publication year - 2008
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/06-0781.1
Subject(s) - biological dispersal , sea breeze , wind speed , seed dispersal , abscission , global wind patterns , prevailing winds , wind direction , ecology , relative humidity , nocturnal , environmental science , sunrise , oceanography , atmospheric sciences , biology , geography , geology , meteorology , botany , population , demography , sociology
Given the dependence of most wind‐pollinated and wind‐dispersed species on low relative humidity (RH) for abscission, and the minimization of RH in the early afternoon, there ought to be a marked directional bias in seed dispersal at sites with a strong local diurnal circulation. We filmed the abscission of seeds of five wind‐dispersed tropical species near the coast of Mexico (Jalisco). We found that (1) most abscission occurred during the period from 10:00 to 17:00 hours; (2) there was a strong bias for landward dispersal due to the midday sea breeze; (3) the little nocturnal dispersal that occurred was toward the sea (due to the night land breeze); (4) there was no abscission in the absence of wind (i.e., indoors) except for one species; and (5) holding relative humidity constant, the proportion of seeds diurnally abscising is strongly correlated with horizontal wind speed. We predict that a similar bias (this time for upslope dispersal) for xerochastic dispersal will occur in complex terrain. We conclude that in coastal and mountainous terrain, dispersal models (and inverse modeling efforts) must include a directionality term.