APPENDIX A 



CRITIQUE OF METHODS 



An adequate study of faunal seasonality requires site-intensive 

 study with summer sampling at 1- or 2-week intervals, a schedule beyond 

 the resources o£ this study. Travel among the study areas was time- 

 consuming and the number of habitats under study was large. These 

 factors combined with weather and tidal patterns to prevent an 

 adequate study of seasonality. In retrospect, effort should have 

 been concentrated in fewer visits so that the survey aspects could 

 have been emphasized and thus provide a more evenly distributed data 

 base covering the various habitats. 



Of the sampling methods used, only the corer samples provided 

 quantitative estimates of animal abundance. The enclosure and clip- 

 quadrat samples were semiquantitative; terrestrial sweep net, drift 

 net, seine, and aquatic sweep net samples provided estimates of 

 relative abundance. Because of these varying characteristics, com- 

 parisons among habitats and samplers have necessarily emphasized 

 relative rather than absolute abundance. The large enclosure method 

 could be made more quantitative by using a device which severs the 

 enclosed vegetation, which could then be rinsed in a dilute formalin 

 solution to remove attached animal life. This method, as with the 

 one used here, does not account for organisms such as oligochaetes 

 and insects which live within living and dead plant tissues and are 

 likely important factors in detrital and grazing food chains. The 

 enclosure apparently could be smaller than the 1-meter diameter used, 

 since sample counts in some cases exceeded several thousand for 

 dominant species. However, this decision should consider the fact 

 that sample counts varied greatly according to season and site. 



Based on the low sample counts obtained for level marsh infauna, 

 a larger sampler than the 918-centimeter-diameter corer used would be 

 desirable, although core depths apparently can be limited to about 5 

 centimeters. This assumes first that the study of this fauna is 

 warranted, and second that an efficient method for separating animals 

 from the soil is available. The silty soils of Siletz Bay were 

 compacted and root-bound and thus resistant to simple methods of 

 animal extraction such as provided by the Berlese funnel. The mostly 

 sandy and peaty nature of soils at Netarts study sites likely would 

 have allowed use of the Berlese funnel, although such use would have 

 created differences of methodology between the two bays. Other methods 

 tend to be time-consuming, arduous, or selective for certain taxa, and 

 also may require special washing racks (Edwards, Dukes, and Axtell, 

 1974; Kline, Dukes, and Axtell, 1975). 



Measurements of invertebrate drift in tidal channels were non- 

 quantitative principally because water speeds were too low to operate 

 the net flow meter (General Oceanics Model 2030). Use of a more 

 sensitive meter or direct measurement of waterflow rate appears 

 necessary if drift is to be quantified. Quantification of fish 

 populations in tidal creeks apparently can be approached through use 

 of nets described by Shenker and Dean (1979) . 



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