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Chapter 7
CONCLUSION
Changes related to resource intensification in the Lower Sacramento Valley are exhibited by the
faunal assemblages presented in this study. These changes are manifest as diachronic differences in
subsistence economies developed in response to divergent resource distributions and technological
efficiency.
By 4,000 years ago, sedentary populations inhabited most of the eastern Delta. Ethnographic
reconstructions (Baumhoff 1963; Johnson 1976), estimate that roughly 5,160 to 5,222 people inhabited the
nearly 1,259 square kilometer (311,000 acre) study area. Populations were concentrated on natural river
levees and areas above the floodplain (Pierce 1988:16, 37). As a result, constricted catchment areas, similar
to those of agricultural populations, were likely. The differing combinations of freshwater marsh, grassland,
and riparian woodland habitats found within each of these catchments would have provided certain
opportunities and constraints for foraging efficiency over time and space for study area populations.
Diachronic disparities exhibited between the zooarchaeological assemblages left by these
populations have led some investigators to conclude that climatic fluctuations and economic intensification
caused encounters with larger taxa, such as artiodactyls and anadromous fish, to decrease over time
throughout California. Two investigations in particular, Broughton (1994b) and Craw (2002), proposed a
decrease in foraging efficiency occurred within the study area over the last 4,000 years. Their
methodologies and results provided the foundation for this thesis.
For this study, three assemblages dating to the Middle Period (SAC-67, SAC-133, and SAC-42)
were compared to three assemblages from the Late Period (SAC-329, SAC-267, and SAC-29). Sites were
divided by habitat based on paleoenvironmental reconstructions, catchment areas were generated, and
assemblage NISPs were subjected to quantitative analyses. In general, the results found that study area
populations during both time periods practiced a subsistence pattern focused on procuring fish, such as
Sacramento perch and Sacramento sucker, and terrestrial resources, such as waterfowl, artiodactyls, and
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fur-bearing mammals from the freshwater marsh. The results also indicated that in Late Period
assemblages, the number of taxa represented increased by 31 percent. At the same time though, numbers of
large bodied taxa, such as artiodactyls, medium mammals, geese, and anadromous fish also increased
significantly.
Several causal factors were examined in order to explain the contradiction between resource
intensification and increased foraging efficiency over time. Population increase was considered inherent
and is reflected in human osteological studies, more occupational sites, and disparate language density
(Bennyhoff 1977:Map 2; Rosenthal et al. 2007:149; Schwitalla 2010:60). Larger numbers of people would
have also restricted catchment areas and possibly led to resource depression, however, results did not
indicate resource patches underutilized before received more exploitation later. The freshwater marsh
remained the habitat most targeted during both the Middle and Late periods, while the grasslands remained
the least targeted area overall. The riparian woodland did show a 340 percent increase in use during the
Late Period, but its status as the second most utilized habitat for the study area did not change. In the end,
the most reasonable explanation for the incongruity between optimal foraging principles was the
introduction of new more efficient hunting technologies, i.e., bows and arrows, and toggle and bilateral
harpoons.
Despite such conclusions, data utilized in this thesis possessed certain limitations. Although
collection methods and general age for assemblages was held constant, inconsistencies in analyst
experience and methodologies could not be controlled. Re-analysis of all the assemblages presented here
was not possible, so certain attributes such as thermal alteration and modification patterns could not be
explored. The lack of consistency in identification to the level of species and age for some taxa, such as
salmonids, waterfowl, and artiodactyls, precluded a discussion on season of capture and harvest pressure.
Lastly, consistent data on the amount and species of freshwater mussel remains would have augmented
patch choice and catchment data.
Hopefully, future research can re-examine the data presented in this thesis in order to minimize
some of the limitations discussed above. Further, research including paleobotanical data would provide a
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more robust picture of the subsistence systems practiced by Lower Sacramento Valley populations.
Comparisons with other indigenous patterns throughout California and beyond would also help to identify
regional trends, and the role climate, population pressure, and technology played for prehistoric subsistence
strategies. Studies relating to paleodemography, settlement patterns, and landscape use may also be able to
build on the paleoenvironmental reconstructions presented here. Above all, I hope that the data presented in
thesis demonstrates the utility of expending time and energy on the study of legacy collections. These
collections often represent the foundations behind the archaeological research and theory in practice today.
And although they can be fraught with deficiencies and challenges, these collections have considerable
potential to add to our understanding of the interplay between humans and the environment they live in.