. The ecology of Tijuana Estuary, California : a national estuarine research reserve. Estuarine ecology -- California Tijuana River Estuary. C\J E O) c E CD o 100 90 80 - 70 - 60 - 50 40 H 30 19 Spartina foliosa TSL —1 Salicornia virginica Mean Cover. 78 —i— 1980 1 1982 1984 1 1986 1 1988 i-80 -70 ^5 -60 CD > o O -50 c CD CD -40 -30 Figure Reciprocal shifts in the abundance of cordgrass (Spartina foliosa) and pickleweed (Salicornia virginica) over the 10-year monitoring program. Flooding occurred in 1980 and 1983; nontidal drought occurred in 1984. Data are from the original 102 lower-
. The ecology of Tijuana Estuary, California : a national estuarine research reserve. Estuarine ecology -- California Tijuana River Estuary. C\J E O) c E CD o 100 90 80 - 70 - 60 - 50 40 H 30 19 Spartina foliosa TSL —1 Salicornia virginica Mean Cover. 78 —i— 1980 1 1982 1984 1 1986 1 1988 i-80 -70 ^5 -60 CD > o O -50 c CD CD -40 -30 Figure Reciprocal shifts in the abundance of cordgrass (Spartina foliosa) and pickleweed (Salicornia virginica) over the 10-year monitoring program. Flooding occurred in 1980 and 1983; nontidal drought occurred in 1984. Data are from the original 102 lower-marsh sampling stations, with means only for quadrats where the respective species occurred (n < 102). TSL = total stem length. Pickleweed may thus have slowed the recovery of cordgrass occurrences (Figure ), even though it appears not to have slowed its biomass recovery in stations where it managed to re-invade (Figure ). The return of tidal conditions in 1985 was followed by a gradual recovery in cordgrass total stem length and pickleweed cover. Interestingly, cordgrass continued to increase in TSL to a new high in 1988 (note that means are for stations of occurrence only). Thus, even though the distribution of cordgrass was far more restricted than in 1979-83, the growing conditions were better where it occurred. Likewise, although pickleweed expanded its distribution after 1984, its average cover declined annually thereafter. It is likely that dredging in 1987 (Entrix et al. 1991) increased overall tidal flows, which should have favored cordgrass. It is unlikely that cordgrass outcompeted pickleweed to force its decline. Nor is it likely that these 1986-88 trends will continue. This will be tested with the 5-year recensus in 1993 (see plan in Section ). Responses of the Mid-Elevation Marsh to Nontidal Drought There were several changes in the mid- elevation marsh plain, which is dominated by pickleweed. The 1984 expansion of the monitoring program to
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