Abundance, species composition, and distribution of buried seeds in a San Francisco Bay salt marsh were studied by collecting soil samples in October and February and observing seedling emergence in the greenhouse. Results were compared with existing vegetation patterns and field germination. Average numbers of buried viable seed down to a 5‐cm depth were 380/ m2 in October and 700/m2 in February, with field germination averaging 118/m2. Salicornia virginica dominated the seed bank in the greenhouse and in field germination. Most other marsh species were present in the seed bank but numbers of seeds were low. A significant correlation was found between highest species diversity and proximity to channels. The nature of this low‐diversity, low‐density seed bank reflects dominance of long‐lived perennial species, seed dispersal patterns and selective environmental pressures.
Benthic core samples were collected monthly from January 1983 through January 1985 at four intertidal sites in San Francisco Bay, California, two in the northern part of the bay (North Bay) and two in the southern part of the bay (South Bay). Considerable variation was observed in numbers of species and individuals at the four sites, and abundances within species varied widely. Temporal changes in species abundances appeared to be related to freshwater inflow patterns and resultant salinity variations in the estuary. The 1982-83 winter season was extremely wet, with heavy freshwater inflow to the bay from January through March, whereas the 1983-84 winter was closer to a normal pattern, with most rainfall occurring from November through January. Species were grouped into four categories depending on their patterns of abundance during the two-year period. Species that showed an abundance peak in the North Bay in 1983 only were Corophiwn sp.B and a Chironomidae larva, apparently responding to the extended period of lowered salinity throughout spring and early summer. Species with an abundance peak only in 1984 included Corophiwn acherusicum, Eteone californica, Nereis sucdnea, and Grandidierella japonica, typical estuarine species that might have been suppressed during the extended freshwater inflows in 1983. Species with peaks in both years were Gemma gemma and Ampelisca abdita in the South Bay; both showed strong seasonal variations. A number of species in both North and South Bays, including dominant members of the intertidal community such as Macoma bahhica and Streblospio benedicti, did not show any consistent seasonal or year-to-year trends. Results of this study suggest that the intensity and timing of freshwater inflow to San Francisco Bay, particularly higher-than-normal inflow during late spring and early summer, may be an important factor in determining the composition of the intertidal benthic communities.
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