The objective of this research was to improve our understanding of how
changes in the environment affect ecological processes. Change detection is often
confounded by the large variation found in ecological data due to the difficulty of
finding replicates in nature. Intertidal communities were chosen for studies of biophysical
interactions because the physical gradients are very strong, thus creating
complex systems within spatial scales that are easily sampled. The selection of
replicate beach habitats was the first step in designing a sampling protocol for
comparative analyses of nearshore community structure. A high resolution shoreline
partitioning model was developed to quantify the physical attributes of homogeneous
shoreline segments and to statistically cluster replicate segments. This model was
applied at 3 locations in Washington State. A portion of the south shore of San Juan
Island was partitioned and the physical attributes quantified. Three groups of rocky
segments differing only in slope angle were selected for biological sampling. The
objective was to test the fidelity of macroalgal and invertebrate populations to replicate
bedrock shore segments. The results showed that community structure and population
abundances were more similar within groups of replicate segments (similar slopes)
than among groups (different slopes). In South Puget Sound, community structure was
compared to test for a deterministic organization of communities among replicate soft
sediment beaches in an estuary. The results showed that replicate beach segments
support similar communities, that communities become less similar as the distance
between replicates increases, and that replicates within or among nearshore cells with
similar temperature and salinity support communities that are more similar than
replicates among cells with different water properties regardless of distance. On the
outer Olympic coast, community comparisons were made among 9 sand beaches over
a shoreline distance of 250 km. The results show that these communities are similar
within segments and within nearshore cells, but because of population abundance
fluctuations, the communities were different among cells and among years. This study
shows that processes determining patterns in nearshore habitats can be quantified,
which is a significant contribution to studies of habitat distribution and the siting of
marine preserves. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28087 |
| Date | 12 May 1999 |
| Creators | Schoch, G. Carl |
| Contributors | Abbott, Mark R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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