tolerances. Based on the 1999, 2001 and 2002 EMAP surveys (Nelson et al. 
2004, 2005, 2007), as well as an EPA survey of the benthos in small estuaries 
(Lee et al. 2003, unpublished data), a species list of 137 species has been 
developed for the small estuaries of the Oregon, Washington, Vancouver Coast 
and Shelf ecoregion. Of the 33 abundant shelf species found in estuaries, eight 
(Spiophanes bombyx, Owenia fusiform is, Paraprionospio pinnata, Rochefortia 
tumida, Prionospio lighti, Leptochelia dubia, and Leitoscoloplos pugettensis) 
were found in these small estuaries. 
These biogeographic patterns suggest that the abundant shelf species 
can be broken into three broad salinity-tolerance groups. The 14 species not 
found within estuaries or only within Southern California estuaries can be 
classified as putative stenohaline species. The eight species found within the 
small estuaries would have the largest relative salinity tolerances, while the 
remaining 11 species found in moderate and large estuaries outside of Southern 
California presumably would have intermediate salinity tolerances. While factors 
other than salinity limit species’ distributions, biogeographical patterns offer an 
approach to generating preliminary relative salinity tolerances for a large number 
of species. 
The present analysis draws information from both the quantitative 
EMAP/NCA survey and from qualitative reports of species’ distributions, with 
each approach providing a different insight into a species’ habitat requirements. 
Biogeographic distributions (Appendix Table 5) can be considered an indicator of 
species’ broad tolerances while the distributional shifts in abundance (Figs. 
3.5.11 - 3.5.14) can be considered an indicator of species’ habitat preferences. 
Thus, the wide latitudinal and estuarine distributions of most species are 
suggestive of wide habitat tolerances among these abundant shelf species. 
However, the pattern of high abundance occurring in only one or two ecoregions 
as observed for several species (e.g., P. californica, M. longicornis, C. pinnata 
and P. occidentalis) suggests a substantially reduced preferred habitat range for 
this set of abundant species. Presumably, species with a more limited preferred 
habitat range would be relatively more susceptible to climate change than those 
with wide ranges. However, species’ responses to sea-surface temperature 
increases are complex and may vary among cold-water and warm-water species 
(e.g., Lima et al. 2007). Nonetheless, future work on comparing species’ 
biogeographic and preferred habitat ranges with sea-surface temperature 
patterns (e.g., MODIS) by ecoregion is one potential avenue to evaluating 
relative risk to climate change for coastal species. It is worth noting that such 
analyses are greatly facilitated by the continuing evolution of biological 
information systems at global (e.g., GBIF) and regional (e.g., PCEIS) scales. 
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