become closed and brackish for very long. 

 If Tijuana Estuary were to close off from 

 tidal inundation for long periods of time, 

 it would probably be marine or hypersaline 

 in response to drought conditions. If 

 runoff were sufficient to create brackish 

 water, the stream flow collected from over 

 700 ha (1,730 ac) would probably be 

 sufficient to breach the sand bar and 

 return tidal conditions. 



Changes in the Foraminifera of Goleta 

 Slough following recent sedimentation have 

 been documented by Lohmar et al. (1980). 

 Stenohaline species, present in earlier 

 sediments, have been replaced by species 

 which can tolerate the fluctuating 

 conditions that accompany the more 

 frequent closure of lagoons with small 

 tidal prisms. Trochammina inflata was the 

 living dominant of salt marsh and tidal 

 creek habitats, while Ammonia becarri was 

 abundant in the deeper lagoon channels. 

 Species with less tolerance for varying 

 salinities (e.g. Elphidium clavatum 

 variants) were restricted to seaward 

 portions of the Slough. 



Foraminifera are helpful in 

 understanding the history of wetlands, and 

 additional detailed studies are needed to 

 determine how regional wetland resources 

 (i.e. areas of channels and low and high 

 marsh habitat) have changed in recent 

 times. 



Molluscs 



The molluscan faunas of Pacific Coast 

 marshes and tidal creeks have been 

 thoroughly sampled and analyzed by 

 Macdonald (1967, 1969). As with other 

 marine animals, there was a distinctive 

 species assemblage south of Point 

 Conception. Examination of large-scale 

 distributional data indicated that biomass 

 increased southward and that most species 

 were more abundant toward the centers of 

 their distributional ranges (Macdonald 

 1967). Otherwise, few patterns of 

 occurrence, were identified, nor were 

 their causes explained. However, 

 since molluscs are only a part of the 



2.5 mm 



2.5 mm 



2.5 mm 



Figure 38. Three common molluscs in 

 southern California salt marshes. 

 Illustrations by J. DeWald. 

 A = Assiminea calif ornica 

 B = Melampus olivaceus 

 C = Cerithidea californica 



59 



