The order Hymenoptera was relatively low in abundance in the low 

 marshes and of moderate abundance in the high marshes (Fig. 3). Few 

 ants (Formicidae) were captured, even in the high marshes, possibly 

 because of the small sampling areas. The majority of the hymenopterans 

 collected were wasps and similar flying forms, which were not further 

 identified. Davis and Gray (1966) stated that all the common Hymenop- 

 tera in the North Carolina marsh were ants; Lane (1969) reported that 

 although an ant species was the most prevalent soil insect in his 

 study, several wasp species were also collected. 



Thysanoptera were common only in the high marshes (high vegetation) 

 of the present study (Fig. 5). Few were identified in Paviour-Smith 

 (1956), Davis and Gray (1966), Lane (1969) and Cameron (1972). 



Other terrestrial insect orders collected in the Oregon marshes 

 were Lipidoptera, Diplura, and Orthoptera (Table 6). These were all 

 of low occurrence in the San Francisco marshes (Lane, 1969; Cameron, 

 1972). However, Teal (1962), Davis and Gray (1966), and Marples (1966) 

 indicated that grasshoppers [Orchelimim) may be common and trophically 

 important in Atlantic coast marshes. The scarcity of orthopterans in 

 Pacific coast collections may be both a matter of chance and the 

 animal's ability to escape collection. However, large populations 

 were not observed in the Oregon marshes. 



The high Acarina populations found in the Oregon low marshes 

 (Fig. 7) have received little attention elsewhere. In contrast, 

 however, Paviour-Smith' s (1956) kite diagrams showed a strong zonation 

 of mites by family, and indicated that highest population density 

 occurred in higher marshes. 



Araneae populations were relatively low in abundance in the low 

 vegetation and, except in the low sand marsh, moderate in abundance 

 in the high vegetation (Figs. 4 and 5). Barnes (1953) provides a 

 thorough description of maritime spider communities in North Carolina. 



A striking feature of the Oregon marsh collections is the scarcity 

 of gastropods, especially in light of MacDonald's (1977) observation 

 that Assimerea transtuoens is ubiquitous across Pacific coast marshes, 

 and that gastropod densities often reach several thousand per square 

 meter. Gastropods are common members of level marsh fauna on the 

 Atlantic coast (Teal, 1962; Nixon and Oviatt, 1973), although Paviour- 

 Smith (1956) apparently found few or no gastropods in New Zealand 

 marshes. It seems unlikely that gastropods were common in the Oregon 

 marsh study areas, since several sites were investigated with varying 

 techniques. More likely, these differences illustrate high variability 

 in faunal composition. 



The fauna of the debris line (Table 2) on the low sand marsh is 

 an interesting blend of taxa found in other habitats. Like other 

 level marsh habitats, the debris line contained large numbers of 

 Acarina and low numbers of Araneae. The collembolan family Isotomidae 



46 



