«**** 



Figure 12. Canada geese ( Branta canadensis ) landing on a marsh. This species eats 

 leaves of Spartina al ternif lora , especially those in the more productive parts of the 

 marsh. In New England, Canada geese may nest on salt marshes and, therefore, 

 concentrate their feeding on marshes during the nesting season. Photo by Rex Schmidt; 

 courtesy U.S. Fish and Wildlife Service. 



Carolina (Sikora et al. 1977) and Great 

 Sippewissett (K. Foreman, Boston 

 University Marine Program, Woods Hole, 

 Mass., pers. comm.). The numbers of soil 

 foraminiferans are comparable to those of 

 nematodes, but the other groups are 

 generally less abundant. 



Water flooding the marsh at high tide 

 contains many planktonic forms. Many of 

 these come from the coastal waters and/or 

 estuaries associated with the marshes. In 

 addition, some of the planktonic animals 

 come from the marsh itself. These are 

 primarily eggs and larvae of marsh inhab- 

 itants. Adult benthic meiofauna may also 

 be dislodged and suspended in the flooding 

 water. All forms of plankton are food for 

 filter feeders on the marsh or for 

 plankton-feeding fish which advance into 

 the marsh on the flooding tide. Plankton 

 leaving on the ebb tide are a food source 

 for filter feeders in channels, on mud- 

 flats, and in the estuary proper. 



Macrofauna . The typical marsh 

 invertebrates--the best studied and 

 probably the most important to the 

 functioning of the intertidal marsh--are 

 the macrofauna. Their definition is 

 complementary to that of the meiofauna: 

 they are retained on a 0.5-mm sieve. The 

 epibenthic fauna (those living above the 

 bottom) are the most familiar even though 

 the infauna (those living within the mud) 

 are usually more abundant. 



Two species of fiddler crabs, Uca 

 pugilator and U. pugnax (Figure 13) , 

 are abundant south of Cape Cod, where 

 there can be 120 indi viduals/m 2 along 

 the creek banks (Krebs and Valiela 1977). 

 Mud crabs ( Panopeus sp.), marsh crabs 

 ( Sesarma reticulatum ) , and green crabs 

 ( Carcinus maenas ) make very conspicuous 

 holes at the edges of marsh creeks. 

 Blue crabs ( Cal 1 inectes sapidus ) , 

 where abundant, are important predators 

 on other marsh animals. They occur as 



21 



