Patterns in Fish Community Structure in a Regulated River

I examined the abundance, composition, and distribution of fish communities in the lower Roanoke River, a hydropeaking system in North Carolina. Fishes were sampled at before and after peaking events over three years; 2007 to 2009. I evaluated trends in species richness, diversity, and assemblage composition. There were no significant differences in either richness or diversity suggesting consistent trends in richness and diversity throughout the study. I used non-metric multidimensional scaling (NMDS) to create a community composition model. Fish composition was noticeably greater post-peaking and changed minimally across time and event. There were no statistically significant differences in species composition among pre or post peaking samples, sites, or years (ANOSIM p < 0.05). I concluded that the small amount of fish community variation observed supports the possibility that the present assemblage has adapted to a regulated flow regime, however a direct relationship between peaking and community composition cannot be established. Additionally, fishes were sampled at three longitudinal sites during summer months of 2007 to 2009. I examined fish community composition to assess longitudinal gradients away from the source of peaking. Differences among fish species within each longitudinal site were examined by use of trophic and habitat/reproductive guilds. Statistically significant differences were detected between both trophic and reproductive guilds among sites and therefore aided in creating a pattern of longitudinal separation in community structure. The fish community of the Roanoke River between Roanoke Rapids and Hamilton does not appear to show signs of variation that may be attributed exclusively to hydropeaking. Changes in hydrology, river morphometry and topography, and habitat structure may account for the longitudinal variation observed in the community structure analyses. The Roanoke River has been regulated for over 50 years. It is possible that the existing fish community has adapted to fluctuating flows created by seasonal hydropeaking. I concluded that in order to develop an appropriate community model and evaluate the full extent of changes in fish community characteristics over time long-term monitoring is needed in the Roanoke River.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environmental Sciences

Year dc:date.available

2010

Author dc:creator

• Davis, Richard

Contributors dc:contributor

• Stephen McIninch

• Roanoke River
• Fish Community
• Fish Diversity
• Regulated Rivers
• Environmental Sciences
• Physical Sciences and Mathematics

Statement dc:rights

• © The Author

Identifier

https://scholarscompass.vcu.edu/etd/73

OAI identifier oai:identifier

oai:scholarscompass.vcu.edu:etd-1072