Table 17. Mammals noted at two southern California marshes by Coulombe (1965) 



•Western harvest mouse ( Reithrodontomys megalotis limicola ) 

 •Ca. meadow mouse = Ca . vole (Microtus californicus Stephens!) 



•Ornate shrew ( Sorex ornatus salicornicus ) 



Deer mouse ( Peromyscus maniculatus ) 



House mouse (Mus musculus ) 



California ground squirrel ( Citellus beecheyii beecheyii ) 



Botta pocket gopher ( Thomomys bottae bottae) 



Black-tailed jack rabbit ( Lepus californicus ) 



Desert cottontail ( Sylvilagus audubonii sactidiegi ) 



Longtail weasel (Mustela frenata latirostra ) 



Striped skunk ( Mephitis mephitis holzneri ) 



Gray fox ( Urocyon cinereoargenteus californicus ) 



Domestic cat (Felis domesticus) 



What aspects of the salt marsh provide 

 survival advantages for marsh-dependent 

 species? Once a species can tolerate its 

 alternating inundation and submergence 

 pattern and can deal with a saline diet, 

 does the salt marsh provide a refuge from 

 competition or predation? Does the small 

 number of species which live there result 

 in fewer negative interactions? Does the 

 vegetation canopy provide protection from 

 carnivores? Or, alternatively, is the 

 salt marsh habitat optimal from a 

 physiological standpoint? Would this 

 fauna do poorly outside the intertidal 

 zone if competitors and predators were not 

 a problem? 



Some insights into these questions 

 are provided by some of the examples in 

 this chapter. McCloy (1979) found that 



hornsnails were more heavily preyed upon 

 on mudflats than in tidal creeks. Boland 

 (1981) found that most shorebirds utilized 

 sand and mudflats, rather than marsh and 

 creek habitats. Willason (1980) suggested 

 that shelter was an important variable in 

 determining the survival of Hemigrapsus 

 oregonensis . The pressure of predation, 

 then, may be lessened underneath the 

 vegetation cover, or within steeply banked 

 creeks where birds are less inclined to 

 feed. 



But reduced feeding by carnivores 

 should lead to higher herbivore densities 

 and greater survival stress for vascular 

 plants and algae. How then does this 

 trophic level maintain such high 

 productivity? How do the algal mats keep 

 up with the grazers? Again, the animals 



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