Defense Date


Document Type


Degree Name

Master of Science


Environmental Studies

First Advisor

Daniel McGarvey


Many aquatic communities demonstrate an inverse scaling relationship between average body mass and density. Using quantitative samples of macroinvertebrates and fishes, we modeled this relationship in three Piedmont streams where little empirical research has been conducted. The size spectra (SS) method, in which individuals are identified by size, not taxonomic identity, was used with linear regression to model density as a function of mass. Fish and benthic invertebrate samples were collected on simultaneous days during September, then used to develop community-level SS models (combined fish and invertebrate data) for each stream. Invertebrate samples were also collected from each stream in July and August, then used to assess whether fish abundance is most strongly associated with prey availability at a prior point in time. Specifically, cross-correlation (xcorr) analysis was used to determine whether the fish SS is most closely associated with the invertebrate SS when invertebrate and fish samples are collected simultaneously, or when invertebrate samples are collected one or two months prior to the fish samples. Differences in SS slopes and intercepts were rarely significant when compared among sites. This was true for SS models that were exclusive to fish or invertebrate samples, as well as community-level models. Collectively, the SS results indicate that fish and invertebrate size structure and density are similar in each of the three study streams. Xcorr results were variable among sites and months, and did not support the hypothesis of a time-staggered link between invertebrate SS and fish SS.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission