Hydro-geomorphological influences on plant patch density and distribution in bedrock shoal habitats of the Cahaba River, AL

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dc.contributor Edmonds, Jennifer
dc.contributor Hart, Justin
dc.contributor.advisor Davis, Lisa
dc.contributor.author Vaughn, Ryan Scott
dc.date.accessioned 2017-03-01T17:37:00Z
dc.date.available 2017-03-01T17:37:00Z
dc.date.issued 2014
dc.identifier.other u0015_0000001_0002090
dc.identifier.other Vaughn_alatus_0004M_11894
dc.identifier.uri https://ir.ua.edu/handle/123456789/2476
dc.description Electronic Thesis or Dissertation
dc.description.abstract Abstract There is a growing body of research that examines bedrock channels. Despite this, biotic-abiotic interactions remain a topic mostly addressed in alluvial systems. This research seeks to identify patch-scale hydro-geomorphic factors operating at the patch-scale in bedrock shoals of the Cahaba River (AL) that help determine the distribution of the emergent aquatic macrophyte, Justicia americana. Macrophyte patch density (number of stems/m2) and percent bedrock void surface area (rock surface area/m2 occupied by joints, fractures, and potholes) were measured (n = 24) using stem counts and underwater photography, respectively. One-dimensional hydrologic modeling (HEC-RAS 4.1.0) was completed for one cross-section within a shoal to examine whether velocity and channel depth are controlling variables for macrophyte patch density. A Pearson's Correlation test between bedrock surface void area and stem density demonstrated a statistically significant positive correlation (r=.665, p=0.01). Results of an independent t-test between the velocity and depth model outputs for within and outside plant patches showed a significant difference in average velocity (p =0.011) and depth (p = 0.001) between the two types of locations across discharges, ranging from 7 m3/sec to 226 m3/sec. These results suggest that the amount of void space present in bedrock surfaces and localized depth and velocity help control the macrophyte patch density, and by extension, the distribution of macrophytes in bedrock shoal complexes. The utility of geomorphology in explaining patch-scale habitat heterogeneity in this study demonstrates potential to use geomorphology to explain macrophyte habitat heterogeneity at reach and system-scales and highlights the need for more research that helps understand biotic-abiotic interactions in bedrock fluvial systems.
dc.format.extent 63 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Geomorphology
dc.subject.other Ecology
dc.title Hydro-geomorphological influences on plant patch density and distribution in bedrock shoal habitats of the Cahaba River, AL
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Geography
etdms.degree.discipline Geography
etdms.degree.grantor The University of Alabama
etdms.degree.level master's
etdms.degree.name M.S.

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