Down by the Riverside: Urban Riparian Ecology

Groffman, Peter M.; Bain, Daniel J.; Band, Lawrence E.; Belt, Kenneth T.; Brush, Grace S.; Grove, J. Morgan; Pouyat, Richard V.; Yesilonis, Ian C.; Zipperer, Wayne C.

doi:10.2307/3868092

Cited by 134 publications

(213 citation statements)

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“…The findings of this study begin to address questions regarding how urbanization affects the function of riparian zones, an understudied area in the urban ecology literature (Groffman et al 2003). This study demonstrates the importance of preserving near-stream remnant riparian areas in cities to maintain patterns of carbon and nutrient fluxes in urban streams.…”

Section: Discussionmentioning

confidence: 89%

Stormflow Dynamics of Dissolved Organic Carbon and Total Dissolved Nitrogen in a Small Urban Watershed

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Yeakley

2005

Biogeochemistry

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We examined patterns of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) loading to a small urban stream during baseflow and stormflow. We hypothesized that lower DOC and TDN contributions from impervious surfaces would dilute natural hydrologic flowpath (i.e., riparian) contributions during storm events in an urban watershed, resulting in lower concentrations of DOC and TDN during storms. We tested these hypotheses in a small urban watershed in Portland, Oregon, over a 3-month period during the spring of 2003. We compared baseflow and stormflow chemistry using Mann-Whitney tests (significant at p<0.05). We also applied a mass balance to the stream to compare the relative significance of impervious surface contributions versus riparian contributions of DOC and TDN. Results showed a significant increase in stream DOC concentrations during stormflows (median baseflow DOC = 2.00 mg l À1 vs. median stormflow DOC = 3.46 mg l À1 ). TDN streamwater concentrations, however, significantly decreased with stormflow (median baseflow TDN = 0.75 mg l À1 vs. median stormflow TDN = 0.56 mg l À1 ). During storms, remnant riparian areas contributed 70-74% of DOC export and 38-35% of TDN export to the stream. The observed pattern of increased DOC concentrations during stormflows in this urban watershed was similar to patterns found in previous studies of forested watersheds. Results for TDN indicated that there were relatively high baseflow nitrogen concentrations in the lower watershed that may have partially masked the remnant riparian signal during stormflows. Remnant riparian areas were a major source of DOC and TDN to the stream during storms. These results suggest the importance of preserving near-stream riparian areas in cities to maintain ambient carbon and nitrogen source contributions to urban streams.

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Section: Discussionmentioning

confidence: 89%

Stormflow Dynamics of Dissolved Organic Carbon and Total Dissolved Nitrogen in a Small Urban Watershed

Hook

Yeakley

2005

Biogeochemistry

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“…Despite reduced spatial variation of nutrient concentrations in this urban watershed (i.e., Fig. 7), high spatial variation in drivers of nutrient limitation such as riparian vegetation (Groffman et al 2003) may directly alter biofilm nutrient limitation status at nearby NDS sites.…”

Section: Hydrological Modificationmentioning

confidence: 99%

Spatial variability in nutrient concentration and biofilm nutrient limitation in an urban watershed

2011

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Nutrient enrichment threatens river ecosystem health in urban watersheds, but the influence of urbanization on spatial variation in nutrient concentrations and nutrient limitation of biofilm activity are infrequently measured simultaneously. In summer 2009, we used synoptic sampling to measure spatial patterns of nitrate (NO 3 -), ammonium (NH 4 ? ), and soluble reactive phosphorus (SRP) concentration, flux, and instantaneous yield throughout the Bronx River watershed within New York City and adjacent suburbs. We also quantified biofilm response to addition of NO 3 -, phosphate (PO 4 3-), and NO 3 -? PO 4 3-on organic and inorganic surfaces in the river mainstem and tributaries. Longitudinal variation in NO 3 -was low and related to impervious surface cover across sub-watersheds, but spatial variation in NH 4 ? and SRP was higher and unrelated to sub-watershed land-use. Biofilm respiration on organic surfaces was frequently limited by PO 4 3-or NO 3 -? PO 4 3-, while primary production on organic and inorganic surfaces was nutrientlimited at just one site. Infrequent NO 3 -limitation and low spatial variability of NO 3 -throughout the watershed suggested saturation of biological N demand. For P, both higher biological demand and point-sources contributed to greater spatial variability. Finally, a comparison of our data to synoptic studies of forested, temperate watersheds showed lower spatial variation of N and P in urban watersheds. Reduced spatial variation in nutrients as a result of biological saturation may represent an overlooked effect of urbanization on watershed ecology, and may influence urban stream biota and downstream environments.

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“…Such ''hydrological droughts'' and lowering of the water Table 1. Impacts of urbanization on stream hydrology and geomorphology (modified from Baer & Pringle, 2000) Changes to stream hydrology Increase in frequency and magnitude of severe floods (Groffman et al, 2003). Williams (1999) observed that many urban streams in semi-arid areas such as Adelaide, South Australia were temporary and their flow regimes had been altered through use as conduits for waste-water, being fed by runoff from domestic use (e.g., watering gardens), or carrying flashy flows from the rapid runoff from impervious catchments.…”

Section: Impacts Of Urbanization On Hydrology and Geomorphologymentioning

confidence: 99%

Managing and Rehabilitating Ecosystem Processes in Regional Urban Streams in Australia

Miller

Boulton

2005

Hydrobiologia

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Urbanization is acknowledged as one of the most severe threats to stream health, spawning recent research efforts into methods to ameliorate these negative impacts. Attention has focused on streams in denselypopulated cities but less populous regional urban centres can be equally prone to some of the same threats yet might not meet the conventional definitions of urban. Several recent reviews have identified the changes to streams that occur during urbanization but they note that few ecological studies have explored ecosystem-level responses, typically focusing instead on state variables such as invertebrate abundance. In many regional urban streams, changes to the extent of impervious drainage have implications for their hydrology and channel morphology but the influence of these changes on fundamental ecosystem processes of leaf litter breakdown and transport compared with those in nearby rural streams are poorly known. The widespread practice of planting exotic trees along riparian zones and street margins draining into urban streams further exacerbates the disruption of natural organic matter dynamics. The combination of seasonal leaf fall by exotic species and the altered drainage patterns through urbanization in Armidale, a regional town in New South Wales, Australia, resulted in contrasting patterns of benthic organic matter storage over 18 months compared to nearby reference and rural streams. Macroinvertebrate detritivore densities were low in the urban stream, implying disruption of the usual biological pathways of leaf breakdown. Understanding the interactions of hydrology, drainage pattern, leaf input and biological attributes of a stream is crucial for managers trying to restore stream ecosystem services without incurring public concern about the appearance of regional urban streams.

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Down by the Riverside: Urban Riparian Ecology

Cited by 134 publications

References 0 publications

Stormflow Dynamics of Dissolved Organic Carbon and Total Dissolved Nitrogen in a Small Urban Watershed

Stormflow Dynamics of Dissolved Organic Carbon and Total Dissolved Nitrogen in a Small Urban Watershed

Spatial variability in nutrient concentration and biofilm nutrient limitation in an urban watershed

Managing and Rehabilitating Ecosystem Processes in Regional Urban Streams in Australia

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