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EFFICACY OF EXPLOSIVE VS. HYGROSCOPIC SEED DISPERSAL BY AN ANNUAL GRASSLAND SPECIES
Author(s) -
Stamp Nancy E.
Publication year - 1989
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 - 10.1002/j.1537-2197.1989.tb11347.x
Subject(s) - biology , germination , seedling , litter , biological dispersal , grassland , seed dispersal , agronomy , burrow , ecology , botany , population , demography , sociology
Seeds of Erodium moschatum (Geraniaceae) were moved on average 56 cm by primary, explosive dispersal and then traveled another 7 cm across the soil surface through activity of the hygroscopic awn, although not necessarily away from the source. In a 10‐day field experiment, 68% of the diaspores buried themselves through activity of the awn. The percentage of seeds becoming buried per day was not correlated with rainfall. More seeds became buried on plant‐littered ground, with litter cover from 8 to 61%, than on bare soil. As soil compaction increased, burial on littered surfaces declined. In laboratory experiments using straw to simulate sparse densities of plant litter, the percent of burial was enhanced, but sticks simulating plant stems did not facilitate burial. In a greenhouse experiment, more buried seeds germinated than unburied seeds. Buried seeds produced seedlings that developed more quickly, had higher survivorship and had greater shoot biomass than those from unburied seeds. Self‐burial also ensured that the radicle was positioned downward, which probably contributed to the observed higher survivorship. Overall, in semiarid grasslands, plant‐littered microhabitats are probably more favorable sites for the placement of seeds than bare areas (e.g., compacted gopher mounds). Littered sites promote self‐burial and burial promotes seedling establishment, survival and growth.