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Dispersion, Dispersal, and Persistence of the Annual Intertidal Alga, Postelsia Palmaeformis Ruprecht
Author(s) -
Dayton Paul K.
Publication year - 1973
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934353
Subject(s) - biological dispersal , biology , intertidal zone , ecology , sporophyte , propagule , mytilus , algae , spore , colonization , limpet , botany , population , demography , sociology
Postelsia palmaeformis is an annual brown alga that occurs on the Washington coast at upper intertidal sites subjected to extreme wave exposure. The alga occurs in patches within beds of Mytilus californianus, the competitive dominant in this region. Postelsia sporophytes are shown to colonize experimentally cleared spaces in beds of Mytilus with no concurrent colonization of adjacent uncleared controls. However, unlike many annual algae which have high spore dispersal abilities, Postelsia seems to have an effective distance of sporophyte colonization of only about 3 m from the edge of existing Postelsia patch. This limited spore dispersal is the mechanism postulated to explain the observed within—patch aggregated distribution also. Postelsia patches are maintained through time by settlement of Postelsia on other algal and animal species. By increasing the probability of both being ripped from the substraturm, and by overgrowing and smothering barnacles, Postelsia sporophytes clear primary substratum for the eventual use of sporophytes of their own species.