Effects of urbanization on the ecological condition of small streams in the inner coastal plain of North Carolina / by Emma C. Hardison.
| Author/creator | Hardison, Emma C. author. |
| Other author | Brinson, Mark M., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 2008. |
| Description | ix, 114 leaves : illustrations (some color), color maps ; 29 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Urbanization is a complex process that degrades the hydrologic, biogeochemical, and habitat functions of stream and riparian ecosystems. This study evaluated the effects of urban landuse on headwater streams in the Inner Coastal Plain of North Carolina, a region experiencing rapid population growth and increasing intensities of human landuses. Nine study sites (0.10 - 3.46 km^) on small streams were chosen to represent a range of urban landuse as quantified by catchment Total Impervious Area (TIA; 3.8 - 56.3%). Sites were studied to examine the effects of urban landuse on stream hydrology and channel morphology. Six of the 9 sites were monitored for riparian groundwater levels and stream-water nutrient and sediment concentrations. Channel incision and increased dominance of stormwater (vs. groundwater) inputs increased in proportion to TIA, while riparian groundwater levels decreased. This phenomenon has resulted in a shift to drier conditions in urban riparian zones, particularly during the summer months. The frequency of overbank flow was not directly related to TIA. Thus, indicators of overbank flow may not signify channel-floodplain connection in urban settings where floodplain saturation is rare. Water quality showed few trends related to TIA, suggesting that other types of land-use within catchments, such as agriculture, may have a greater influence on certain water quality parameters. Only ammonium and total suspended sediment concentrations, which are greatly influenced by storm runoff, were directly related to TIA. In contrast, nitrate and phosphorus concentrations did not correlate with TIA, suggesting that agricultural landuses exert a major influence over these nutrients in the region. Vegetation analyses were conducted at urban sites and compared to vegetation cover classes from a study of rural headwater streams in the region. Biomass estimates were not significantly different between the two settings. Urban classes, however, exhibited higher species richness than did rural cover classes in part due to the prevalence of non-native species in urban areas, particularly in the understory. Biomass and species composition were also measured within 'Urban Wooded Landscapes,' a new category consisting of a canopy of mature trees without a natural understory and ground cover. Landuse classes such as commercial or low-density residential do not differentiate between land management decisions at the parcel scale that can greatly affect biomass. However, landuse practices that leave a large proportion (at least 75%) of tree-canopy vegetation intact can result in residential biomass comparable to similar forested cover types in rural riparian zones, especially for stands with trees >50 years old. Reach-scale estimates of riparian vegetation may be less useful as an ecological indicator in urban systems because of the high level of alterations, such as channel incision, that are relatively independent of management practices that determine urban forest biomass. |
| General note | Presented to the faculty of the Department of Biology. |
| General note | Advisor: Mark M. Brinson |
| Dissertation note | M.S. East Carolina University 2008 |
| Bibliography note | Includes bibliographical references (leaves 94-101). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
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|---|---|---|---|---|
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| Electronic Resources | ✔ Available |