CHAPTER 5 

 SALT MARSH ANIMALS 



The salt marsh contains an 

 interesting mixture of animals and plants 

 that come from two extremely different 

 environments: the land and the sea. The 

 vascular plants, insects, amphibians, 

 reptiles, birds and mammals are familiar 

 terrestrial forms. In contrast, algae, 

 molluscs, crustaceans, and fish are all 

 expected to occur in aquatic habitats. 

 Intertidal marshes, which are 

 alternatingly wet and dry, harbor all of 

 these forms. We might expect the 

 "terrestrial" organisms to be stressed 

 during high tides when the aquatic biota 

 are not, and vice versa at low tide. It 

 is intriguing to consider whether the 

 species which manage to live here do so 

 out of preference or default. As 

 considered earlier, the vascular plants 

 generally find southern California 

 wetlands stressful; they appear to owe 

 their success to tolerance of rather than 

 preference for the marsh environment. 

 Insects and mammals somehow cope with 

 occasional inundation and salty foods, but 

 we are ignorant of how stressful these 

 conditions are. The highly mobile birds 

 can easily avoid inundation, but they must 

 expend considerable energy to excrete 

 excess salts. For the marine organisms, 

 desiccation and variable temperatures 

 surely pose a threat to survival. 

 Although algal productivity seems to 

 increase as tide waters subside, (R. 

 Holmes, University of California, Santa 

 Barbara) molluscs close up when they're 

 exposed; crustaceans seek shelter; and 

 fish move back to channels. These animal 

 behavior patterns all suggest tolerance, 

 rather than preference for marsh 

 environments. Yet there must be some 

 advantage to life in the salt marsh; 

 otherwise we would find salt marsh animals 

 more numerous elsewhere instead of 

 dependent on this unique community. 



This chapter summarizes what is known 

 about southern California salt marsh 

 animals. How the various groups tolerate 

 their fluctuating environments is not well 



understood, and there is much to learn 

 about their interactions with one another. 

 These topics and questions concerning 

 ecosystem energy flow should provide 

 future wetland ecologists with substantial 

 material for study. 



5.1 INVERTEBRATES 



Investigations of the invertebrates 

 of bay, lagoon and intertidal flat 

 habitats have been conducted in recent 

 years (Peterson 1975, 1977, Seapy 1981, 

 Quammen 1980), but information on the salt 

 marsh invertebrates is quite restricted. 

 Macdonald (1967) and McCloy (1979) have 

 studied molluscs in selected Pacific Coast 

 marshes; Phleger (1977) and others have 

 investigated the Foraminifera ; Willason 



(1980) has studied crabs; and Nagano 



(1981) is investigating insects in a 

 variety of coastal habitats. Our 

 knowledge of marsh nematodes, harpacticoid 

 copepods, annelids, amphipods, isopods, 

 and arachnids is extremely limited. Since 

 these small animals are likely to be major 

 consumers in the salt marsh food chain, as 

 well as important food sources for birds 

 and fish, further research is needed to 

 quantify their habitat requirements and 

 roles in the marsh ecosystem. 



Foraminifera 



Marsh Foraminifera are useful in 

 unraveling the history of sediments. 

 These small protozoa live in the upper 1 

 cm of marsh soils; their shells are 

 readily identifiable and well preserved. 

 However, because of their calcareous 

 composition, they do not persist in acidic 

 substrates. Some forms (called 

 arenaceous) build their shells by 

 cementing sand grains. 



Phleger (1977), Phleger and Bradshaw 

 (1966), and Scott (1976) discussed the 

 Foraminifera of salt marsh soils and 



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