Record Details
Field | Value |
---|---|
Title | Untangling the complexity of nearshore ecosystems : examining issues of scaling and variability in benthic communities |
Names |
Schoch, G. Carl
(creator) Abbott, Mark R. (advisor) |
Date Issued | 1999-05-12 (iso8601) |
Note | Graduation date: 2000 |
Abstract | 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. |
Genre | Thesis/Dissertation |
Topic | Benthos -- Washington (State) |
Identifier | http://hdl.handle.net/1957/28087 |