Estero de Punta Banda (Ibarra-Obando 

 1991). A large corner of the estuary was 

 diked to exclude tidal flushing. Ibarra-Obando 

 compared the composition of salt marshes 

 inside and outside the dike and documented the 

 same changes during the same year of very 

 low rainfall (1984). Soil salinities 

 skyrocketed while soil moisture dropped. 

 Perennial pickleweed flourished, and annual 

 pickleweed and sea-blite declined sharply in 

 both their frequency of occurrence and 

 percent cover. Her results strongly support 

 the above interpretation that the coincidence 

 of nontidal drought and the decline of short- 

 lived species is a cause-effect relationship. 



Whether or not either short-lived species 

 will recover at Tijuana Estuary depends in 

 part on management of the estuary. Dredging 

 reopened the estuary mouth in December 

 1984 and increased tidal flushing beyond what 

 it was in 1983 (Entrix et al. 1991). Yet 

 perennial pickleweed remains abundant and 

 there is little open space for seedling 

 establishment. The seed bank no doubt 

 remains depleted. A rapid recovery of either 

 species would require a reduction in the 

 perennial pickleweed canopy and seeding to 

 replenish the seed bank. Neither is 

 recommended at this stage. Rather, studies of 

 the importance of these species to the salt 

 marsh biota and long-term evaluation of their 

 (potential) expansion are suggested. 



5.3.3 Mid-Elevation Dynamics After 1984 



Extreme events have not significantly 

 altered the monitored areas of salt marsh 

 since tidal flushing was restored in December 

 1984. The 1988 sea storm altered the inlet 

 (Webb et al. 1989) and had catastrophic 

 impacts on the dunes (Fink 1989), but 

 Oneonta Slough did not close and there was no 

 interruption in tidal flushing. Data from the 

 expanded monitoring program thus provide a 

 new baseline record of the post-closure salt 

 marsh. 



At the whole-marsh scale, species 

 composition appeared to be very stable from 

 1985 through 1988 (Figure 5.5). In 216 

 quadrats, the only notable shift was an 



100 -\ 



Salicornia virginica 



o 



=3 



o 

 o 



O 



o 



c 

 <x> 



=5 



cr 

 a> 



T T 1 1 1 



)83 1984 1985 1986 1987 1988 



Figure 5.5. Dynamics of salt marsh vegeta- 

 tion (cordgrass excluded) following the 8- 

 month closure (April-mid Dec, 1984) of the 

 ocean inlet. Data are from Griswold and 

 Zedler (1990; n = 216 quadrats). M.I. = 

 Monanthochloe littoralis; T.c. = Triglochin 

 concinnum; S.s. = Salicornia subterminalis; 

 D.s. = Distichlis spicata. 



increase in salt wort (Batis maritima) i n 

 1986. At the individual quadrat scale, 

 however, the marsh proved to be much more 

 dynamic. Several species appeared and 

 disappeared from quadrats even when their 

 overall occurrence was nearly constant 

 (Griswold and Zedler 1990). Perennial 

 pickleweed (Salicornia virginica) was the 

 most dynamic of the species, appearing and 



107 



