terrestrial animals in the cr: .er or were washed in 



during tidal submergence. Diptera oi: the tvvo creeks were quite differ- 

 ent, being quite diverse in the ?edge creek and limited to a few taxa in 

 the mature high creek. This i ct the comparatively large amounts 

 of filamentous algae occurrin: sedge creek at the time of 

 sampling. The algae appeared to huvc high densities of dipterous lar- 

 vae and other taxa captured by the nquatic sweep net and the corer. 

 The grapsid crab, Hemigipapsus sis, was also common in the algae, 



although it was not quantitatl >pled. 



The infauna of the sedge r in many respects 



to the infauna of the sedge ci^. „„.,.. ,^. -u,^,. ^2). The tidal flat 



is located near the bayward outlet of the creek, and both the creek 

 and the tidal flat have muddy substrates. The tidal flat infauna was 

 relatively poor in Diptera, however, having only low densities of 

 dolichopodid larvae. Other differences included a lower density of a 

 burrowing cnidarian, and the addition of a sacoglossan gastrod, Alderia. 



The infauna of the sandy tidal flat located below the low sand 

 marsh (Netarts Bay) differed from the infauna of the sedge tidal flat 

 in having a relatively greater abundance of polychaetes (principally 

 Haplosaoloplos) and an Eohaustroius-Paraphoxus amphipod fauna, in con- 

 trast to the Corophium -dominsLted fauna at the sedge mudflat. The 

 decapod shrimp, Callianassa, and tfie bivalve, Cryptomya calif omica, 

 an inhabitant of Callianassa burrows, were also present in the sandy 

 tidal flat. 



— 









= 



TIDAL FLAT SOIL 











58 



24 June 1978 





— 







r- 





n.7I,404/n.^ 





_ 



*■ 



' * 







*n *n n 



* 



2 E 



C=3 



* * * I — I* * * * 



* j — * * I *l — I 



I 5 S 



_ 





71 



TID/.L FL.M SOIL 



=3 



93 





e — 



n=16, 545/0^ 









n=4,333/m^ 



n_ 



^. 





„ n 





^ * 



r-Ti 



n 



I g g 3||| H 



^ S 0; tj ^ < ^ 



3 a 



& 



i S^ a 3 



Figure 12. Taxonomic structure of pan water invertebrate community, 

 n = average for replicate, samples on dates shown. * = <1 

 percent. Life stage is adult unless otherwise indicated. 



