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Sample records for adjacent riparian zone

  1. PLANT INVASIONS IN RHODE ISLAND RIPARIAN ZONES

    EPA Science Inventory

    The vegetation in riparian zones provides valuable wildlife habitat while enhancing instream habitat and water quality. Forest fragmentation, sunlit edges, and nutrient additions from adjacent development may be sources of stress on riparian zones. Landscape plants may include no...

  2. Non-native earthworms in riparian soils increase nitrogen flux into adjacent aquatic ecosystems.

    PubMed

    Costello, David M; Lamberti, Gary A

    2008-12-01

    -buffering capacity of riparian zones and altering stoichiometric relationships in adjacent aquatic ecosystems. PMID:18825416

  3. Changes In Tree Species In Riparian Zones Of Urban Streams May Have Effects On Restoration And Storm Water Control Efforts

    EPA Science Inventory

    A riparian zone is the land and vegetation within and directly adjacent to surface water ecosystems, such as lakes and streams. The vegetation in riparian zones provides ecosystem services (such as reducing flooding and bank erosion and reducing levels of pollutants in streams) ...

  4. Groundwater-surface water interaction in the riparian zone of an incised channel, Walnut Creek, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Li, Z.; Zhang, Y.-K.

    2006-01-01

    Riparian zones of many incised channels in agricultural regions are cropped to the channel edge leaving them unvegetated for large portions of the year. In this study we evaluated surface and groundwater interaction in the riparian zone of an incised stream during a spring high flow period using detailed stream stage and hydraulic head data from six wells, and water quality sampling to determine whether the riparian zone can be a source of nitrate pollution to streams. Study results indicated that bank storage of stream water from Walnut Creek during a large storm water runoff event was limited to a narrow 1.6 m zone immediately adjacent to the channel. Nitrate concentrations in riparian groundwater were highest near the incised stream where the unsaturated zone was thickest. Nitrate and dissolved oxygen concentrations and nitrate-chloride ratios increased during a spring recharge period then decreased in the latter portion of the study. We used MODFLOW and MT3DMS to evaluate dilution and denitrification processes that would contribute to decreasing nitrate concentrations in riparian groundwater over time. MT3DMS model simulations were improved with a denitrification rate of 0.02 1/d assigned to the floodplain sediments implying that denitrification plays an important role in reducing nitrate concentrations in groundwater. We conclude that riparian zones of incised channels can potentially be a source of nitrate to streams during spring recharge periods when the near-stream riparian zone is largely unvegetated. ?? 2005 Elsevier B.V. All rights reserved.

  5. Denitrification and patterns of electron donors and acceptors in 8 riparian zones with contrasting hydrogeology

    NASA Astrophysics Data System (ADS)

    Vidon, P.; Hill, A.

    2004-12-01

    A better understanding of nitrate removal mechanisms is important for managing the water quality function of stream riparian zones. We examined the linkages between hydrologic flow paths, patterns of electron donors and acceptors and the importance of denitrification as a nitrate removal mechanism in 8 riparian zones on glacial till and outwash landscapes in southern Ontario, Canada. Nitrate-N concentrations in shallow groundwater from adjacent cropland declined from levels that were often 10-30 mg L-1 near the field-riparian edge to <1 mg L-1 in the riparian zones throughout the year. Chloride data suggest that dilution cannot account for most of this nitrate decline. Despite contrasting hydrogeologic settings, these riparian zones displayed a well-organized pattern of electron donors and acceptors that resulted from the transport of oxic nitrate-rich groundwater to portions of the riparian zones where low DO concentrations and an increase in DOC concentrations were encountered. The natural abundances of d15N and in situ acetylene injection to piezometers indicate that denitrification is the primary mechanism of nitrate removal in all of the riparian zones. Our data indicate that effective nitrate removal by denitrification occurs in riparian zones with hydric soils as well as in non-hydric riparian zones and that a shallow water table is not always necessary for efficient nitrate removal by denitrification. The location of "hot spots" of denitrification within riparian areas can be explained by the influence of key landscape variables such as slope, sediment texture and depth of confining layers on hydrologic pathways that link supplies of electron donors and acceptors.

  6. Groundwater-Stream Interactions in a Seasonal Flooded Riparian Zone

    NASA Astrophysics Data System (ADS)

    Jensen, J. K.; Engesgaard, P. K.; Nilsson, B.

    2011-12-01

    At Odense River in Denmark several wetlands/riparian zones have recently been reconstructed with one objective to rehabilitate the wetland/riparian zone as a buffer strip enhancing depletion of agricultural inputs of diffuse pollutants like nutrients and pesticides to the receiving Odense River. The approach is initiated to either force the polluted groundwater through a reactive buffer strip and/or allowing polluted river water to flood and infiltrate the reactive riparian zone. However, often the hydraulics of these systems is poorly understood and therefore it is difficult to evaluate the efficiency of the systems and several questions often remain unanswered; Is residence time in the riparian zone long enough to sufficiently deplete the pollutants? What are the effects of flooding and infiltration of polluted river water on the hydraulics of the buffer strip? Can differences in groundwater flow paths in periods with flooding reduce the effect of the buffer strip by shortening flow paths to the surface water and hence alter residence time; that is, does groundwater-stream interaction change during and after flooding? And finally; is it possible to upscale the overall effect for a whole river system? Monitoring is ongoing in a reconstructed riparian zone heavily polluted with nitrate as a part of the EU project AQUAREHAB. The setup is a grid of 50 piezometers installed in selected transects following groundwater flow paths from an adjacent agricultural site to the river. The piezometer setup permits us to follow the changes in hydraulic heads and to perform water sampling for chemical characterization. The site has been characterized by geophysical Multi-Electrode-Profiling and correlated to two geotechnical drillings to depths of 20 m, by slug-test, and hydro periods have been determined from continuous recording of river stage. Temperature is used as a tracer for monitoring discharge of groundwater to the stream (non-continuous converted to an estimate of flux

  7. Riparian Zone Evapotranspiration Estimates using Streamflow Diel Signals

    NASA Astrophysics Data System (ADS)

    Geisler, E.; McNamara, J. P.; Benner, S. G.; Flores, A. N.

    2015-12-01

    Diel climate variations impact vegetation and hydrologic systems in semi-arid mountainous watersheds primarily through transpiration. The impact diel variations have are particularly evident in streamflow during low flows. Understanding the controls on streamflow diel signals and the interaction they have within the riparian zone has been a focus of multiple studies to better understand the riparian zones as a system. The focus of the study was to monitor streamflow diel signals at five gauging stations within the same watershed to calculate riparian zone evapotranspiration (ET) and to understand diel signal variability throughout the watershed. Amplitude and timing of diel signals were analyzed at each site and used in determining controls on the diel signal. Meteorological and sap flux measurements were also monitored on both hillslope and riparian areas for comparison of fluxes. A spatially distributed hypsometric method was used to calculate ET for each gauging station sub-watershed for comparison with riparian ET estimates. The study found that, with the use of diel signals and a fixed riparian area, the estimated riparian zone ET ranged from a fraction to several times the calculated meteorological ET depending on the season. Although the riparian zone ET calculation was highly variable, it was constrained using diel signal timing and amplitude. Observations of differences in hillslope and riparian zone meteorological and sap flux variables also supported diel signal calculations. The study concludes that riparian zone ET is a substantial contributor to watershed scale ET during the summer months and that streamflow diel signal plays a large role in understanding watershed scale interactions and the riparian zone's influence on a semi-arid watershed.

  8. Influence of Gully Erosion Control on Amphibian and Reptile Communities within Riparian Zones of Channelized Streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian zones of streams in northwestern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Riparian gully formation has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used conservation practice for...

  9. Shallow groundwater denitrification in riparian zones of a headwater agricultural landscape.

    PubMed

    Anderson, Todd R; Groffman, Peter M; Kaushal, Sujay S; Walter, M Todd

    2014-03-01

    Riparian zones adjacent to cropped lands are effective at reducing nitrate (NO) loads to receiving water bodies primarily through plant assimilation and denitrification. Denitrification represents a permanent removal pathway and a greenhouse gas source, converting NO to inert N gas or nitrous oxide (NO), and has been the subject of many studies in agricultural landscapes. Despite the prevailing notion that riparian zones can be areas of enhanced denitrification, there is a lack of in situ denitrification measurements from these areas that buffer streams and rivers from NO originating in upland cropped soils, especially over time scales that capture seasonal dynamics. We measured in situ groundwater denitrification rates in two riparian zones of an intensive dairy farm located in the headwaters of the Susquehanna River. Denitrification rates determined monthly over a 1-yr period with the N-NO push-pull method ranged from 0 to 4177 μg N kg soil d (mean, 830 ± 193 μg N kg soil d). Denitrification showed a distinct seasonal pattern, with highest rates observed in the spring and summer, concomitant with warmer temperatures and decreasing dissolved oxygen. We estimate an annual N loss of 470 ± 116 kg yr ha of riparian zone via denitrification in the shallow saturated zone, with the potential for >20% of this amount occurring as NO. Total denitrification from shallow groundwater in the riparian zone was equivalent to 32% of manure N spread on the adjacent upland field, confirming the importance of riparian zones in agricultural landscapes at controlling N loads entering downstream waters. PMID:25602674

  10. The Role of Legacy Effects and Reactive Amendments on Phosphorus Retention Within Riparian Zones

    NASA Astrophysics Data System (ADS)

    Surridge, B.; Habibiandehkordi, R.; Quinton, J.

    2014-12-01

    Undisturbed riparian zones, including river floodplains and field buffer strips, can significantly reduce phosphorus (P) export associated with agricultural production. However, riparian zones are frequently disturbed, including through conversion to agricultural land. Restoring disturbed riparian zones is promoted widely within agri-environment schemes. However, restoration presents significant challenges, two of which are considered in this paper: understanding the impacts of restoration on legacy P within riparian zone soils; and maximising the efficacy of riparian zones for removal of all P fractions, including the more immediately bioavailable soluble P fractions. Firstly, we examine changes in porewater soluble P concentration following re-wetting of a river floodplain in Norfolk, UK, using laboratory mesocosms and in-situ field monitoring. Substantial release of P from sediment to porewater was observed following re-wetting (porewater soluble P concentration exceeded 6.5 mg P L-1), probably associated with reductive-dissolution of iron-bound P within floodplain sediments. Export of soluble P from porewater into adjacent receiving waters was observed following both natural hydrological events and management of the hydrological regime within the floodplain. Secondly, we examine how retention of soluble P with grass buffer strips can be enhanced through application of reactive industrial by-products, focussing on ochre and aluminium-based water treatment residuals. Application of these by-products to buffer strips increased removal of soluble P from surface runoff by over 50% compared to non-amended buffer strips. The long-term effectiveness of reactive amendments is also considered, using repeated runoff events under field conditions. Taken together, the research offers new insights into riparian zone P biogeochemistry within agricultural landscapes.

  11. Breeding bird response to partially harvested riparian management zones

    USGS Publications Warehouse

    Chizinski, Christopher J.; Peterson, Anna; Hanowski, JoAnn; Blinn, Charles R.; Vondracek, Bruce C.; Niemi, Gerald

    2011-01-01

    We compared avian communities among three timber harvesting treatments in 45-m wide even-age riparian management zones (RMZs) placed between upland clearcuts and along one side of first- or second-order streams in northern Minnesota, USA. The RMZs had three treatments: (1) unharvested, (2) intermediate residual basal area (RBA) (targeted goal 11.5 m2/ha, realized 16.0 m2/ha), and (3) low RBA (targeted goal 5.7 m2/ha, realized 8.7 m2/ha). Surveys were conducted one year pre-harvest and three consecutive years post-harvest. There was no change in species richness, diversity, or total abundance associated with harvest but there were shifts in the types of birds within the community. In particular, White-throated Sparrows (Zonotrichia albicollis) and Chestnut-sided Warblers (Dendroica pensylvanica) increased while Ovenbirds (Seiurus aurocapilla) and Red-eyed Vireos (Vireo olivaceus) decreased. The decline of avian species associated with mature forest in the partially harvested treatments relative to controls indicates that maintaining an unharvested RMZ adjacent to an upland harvest may aid in maintaining avian species associated mature forest in Minnesota for at least three years post-harvest. However, our observations do not reflect reproductive success, which is an area for future research.

  12. Nitrate removal in a restored riparian groundwater system: functioning and importance of individual riparian zones

    NASA Astrophysics Data System (ADS)

    Peter, S.; Rechsteiner, R.; Lehmann, M. F.; Brankatschk, R.; Vogt, T.; Diem, S.; Wehrli, B.; Tockner, K.; Durisch-Kaiser, E.

    2012-11-01

    For the design and the assessment of river restoration projects, it is important to know to what extent the elimination of reactive nitrogen (N) can be improved in the riparian groundwater. We investigated the effectiveness of different riparian zones, characterized by a riparian vegetation succession, for nitrate (NO3-) removal from infiltrating river water in a restored and a still channelized section of the river Thur, Switzerland. Functional genes of denitrification (nirS and nosZ) were relatively abundant in groundwater from willow bush and mixed forest dominated zones, where oxygen concentrations remained low compared to the main channel and other riparian zones. After flood events, a substantial decline in NO3- concentration (> 50%) was observed in the willow bush zone but not in the other riparian zones closer to the river. In addition, the characteristic enrichment of 15N and 18O in the residual NO3- pool (by up to 22‰ for δ15N and up to 12‰ for δ18O) provides qualitative evidence that the willow bush and forest zones were sites of active denitrification and, to a lesser extent, NO3- removal by plant uptake. Particularly in the willow bush zone during a period of water table elevation after a flooding event, substantial input of organic carbon into the groundwater occurred, thereby fostering post-flood denitrification activity that reduced NO3- concentration with a rate of ~21 μmol N l-1 d-1. Nitrogen removal in the forest zone was not sensitive to flood pulses, and overall NO3- removal rates were lower (~6 μmol l-1 d-1). Hence, discharge-modulated vegetation-soil-groundwater coupling was found to be a key driver for riparian NO3- removal. We estimated that, despite higher rates in the fairly constrained willow bush hot spot, total NO3- removal from the groundwater is lower than in the extended forest area. Overall, the aquifer in the restored section was more effective and removed ~20% more NO3- than the channelized section.

  13. Nitrate removal in a restored riparian groundwater system: functioning and importance of individual riparian zones

    NASA Astrophysics Data System (ADS)

    Peter, S.; Rechsteiner, R.; Lehmann, M. F.; Brankatschk, R.; Vogt, T.; Diem, S.; Wehrli, B.; Tockner, K.; Durisch-Kaiser, E.

    2012-06-01

    For the design and the assessment of river restoration projects, it is important to know to what extent the elimination of reactive nitrogen (N) can be improved in the riparian groundwater. We investigated the effectiveness of different riparian zones, characterized by a riparian vegetation succession, on nitrate (NO3-) removal from infiltrating river water in a restored and a still channelized section of the River Thur, Switzerland. Functional genes of denitrification (nirS and nosZ) were relatively abundant in groundwater from willow bush and mixed forest dominated zones, where oxygen concentrations remained low compared to the main channel and other riparian zones. After flood events, a substantial decline in NO3- concentration (>50 %) was observed in the willow bush zone, but not in the other riparian zones closer to the river. In addition, the characteristic enrichment of 15N and 18O in the residual NO3- pool (by up to 22 ‰ for δ15N and up to 12 ‰ for δ18O) provides qualitative evidence that the willow bush and forest zones were sites of active denitrification and, to a lesser extent, NO3- removal by plant uptake. Particularly in the willow bush zone, during a period of water table elevation after a flooding event, substantial input of organic carbon into the groundwater occurred, thereby fostering post-flood denitrification activity that reduced NO3- concentration with a rate of ~21 μmol N l-1 d-1. Nitrogen removal in the forest zone was not sensitive to flood pluses, and overall NO3- removal rates were lower (~6 μmol l-1 d-1). Hence, discharge-modulated vegetation-soil-groundwater coupling was found to be a~key driver for riparian NO3- removal. We estimated that, despite higher rates in the fairly constrained willow bush hot spot, total NO3- removal from the groundwater is lower than in the extended forest area. Overall, the aquifer in the restored section was more effective and removed ~20 % more NO3- than the channelized section.

  14. Ecological functions of riparian zones in Oregon hydrological landscapes

    EPA Science Inventory

    The ecological functions of streams and associated riparian zones are strongly influenced by the hydrological attributes of watersheds and landscapes in which they occur. Oregon hydrologic landscape regions (HLRs) have been defined based on four types of GIS data: 1) climate, 2) ...

  15. Nitrous oxide emission from cropland and adjacent riparian buffers in contrasting hydrogeomorphic settings.

    PubMed

    Fisher, K; Jacinthe, P A; Vidon, P; Liu, X; Baker, M E

    2014-01-01

    Riparian buffers are important nitrate (NO) sinks in agricultural watersheds, but limited information is available regarding the intensity and control of nitrous oxide (NO) emission from these buffers. This study monitored (December 2009-May 2011) NO fluxes at two agricultural riparian buffers in the White River watershed in Indiana to assess the impact of land use and hydrogeomorphologic (HGM) attributes on emission. The study sites included a riparian forest in a glacial outwash/alluvium setting (White River [WR]) and a grassed riparian buffer in tile-drained till plains (Leary Weber Ditch [LWD]). Adjacent corn ( L.) fields were monitored for land use assessment. Analysis of variance identified season, land use (riparian buffer vs. crop field), and site geomorphology as major drivers of NO fluxes. Strong relationships between N mineralization and NO fluxes were found at both sites, but relationships with other nutrient cycling indicators (C/N ratio, dissolved organic C, microbial biomass C) were detected only at LWD. Nitrous oxide emission showed strong seasonal variability; the largest NO peaks occurred in late spring/early summer as a result of flooding at the WR riparian buffer (up to 27.8 mg NO-N m d) and N fertilizer application to crop fields. Annual NO emission (kg NO-N ha) was higher in the crop fields (WR: 7.82; LWD: 6.37) than in the riparian areas. A significant difference ( < 0.02) in annual NO emission between the riparian buffers was detected (4.32 vs. 1.03 kg NO-N ha at WR and LWD, respectively), and this difference was attributed to site geomorphology and flooding (WR is flood prone; no flooding occurred at tile-drained LWD). The study results demonstrate the significance of landscape geomorphology and land-stream connection (i.e., flood potential) as drivers of NO emission in riparian buffers and therefore argue that an HGM-based approach should be especially suitable for determination of regional NO budget in riparian ecosystems.

  16. Nitrous oxide emission from cropland and adjacent riparian buffers in contrasting hydrogeomorphic settings.

    PubMed

    Fisher, K; Jacinthe, P A; Vidon, P; Liu, X; Baker, M E

    2014-01-01

    Riparian buffers are important nitrate (NO) sinks in agricultural watersheds, but limited information is available regarding the intensity and control of nitrous oxide (NO) emission from these buffers. This study monitored (December 2009-May 2011) NO fluxes at two agricultural riparian buffers in the White River watershed in Indiana to assess the impact of land use and hydrogeomorphologic (HGM) attributes on emission. The study sites included a riparian forest in a glacial outwash/alluvium setting (White River [WR]) and a grassed riparian buffer in tile-drained till plains (Leary Weber Ditch [LWD]). Adjacent corn ( L.) fields were monitored for land use assessment. Analysis of variance identified season, land use (riparian buffer vs. crop field), and site geomorphology as major drivers of NO fluxes. Strong relationships between N mineralization and NO fluxes were found at both sites, but relationships with other nutrient cycling indicators (C/N ratio, dissolved organic C, microbial biomass C) were detected only at LWD. Nitrous oxide emission showed strong seasonal variability; the largest NO peaks occurred in late spring/early summer as a result of flooding at the WR riparian buffer (up to 27.8 mg NO-N m d) and N fertilizer application to crop fields. Annual NO emission (kg NO-N ha) was higher in the crop fields (WR: 7.82; LWD: 6.37) than in the riparian areas. A significant difference ( < 0.02) in annual NO emission between the riparian buffers was detected (4.32 vs. 1.03 kg NO-N ha at WR and LWD, respectively), and this difference was attributed to site geomorphology and flooding (WR is flood prone; no flooding occurred at tile-drained LWD). The study results demonstrate the significance of landscape geomorphology and land-stream connection (i.e., flood potential) as drivers of NO emission in riparian buffers and therefore argue that an HGM-based approach should be especially suitable for determination of regional NO budget in riparian ecosystems. PMID:25602568

  17. Nitrate Removal in Stream Riparian Zones: The Last Fifteen Years

    NASA Astrophysics Data System (ADS)

    Duval, T. P.

    2009-05-01

    Anthropogenic loadings of nitrate from agricultural fertilizer use and deforestation can result in levels deleterious to stream ecosystems and downstream receiving water bodies. Riparian zones represent perhaps our most effective management tool in mitigating these elevated stream nitrate levels. In many settings these interfaces between the terrestrial and the aquatic have been shown to efficiently remove elevated nitrate loadings through denitrification and/or plant uptake. However, it was realized early that some riparian zones are not effective nitrate removers, and the relative importance of plant uptake versus denitrification was unclear. The uncertainty that existed 15 years ago fueled a plethora of studies on nitrate removal in stream riparian zones. This talk will highlight the most important findings of this research over the last decade and a half. Notably, the detailed description of hydrological flowpaths into and through riparian zones to the downstream environment has gone a long way to explaining the ineffectiveness of some riparian zones. Furthermore, the use of 15-N isotope tracers and field and lab incubation studies have aided in quantifying the importance of the denitrification pathway of removal. Patterns of terminal electron donors and acceptors and the importance of the intersection of the nitrate-elevated water with a source of bioavailable organic carbon, including deeply buried carbon, were a series of key achievements. Somewhat surprisingly, it has been shown that hydrogeology/landscape setting has a greater control on nitrate removal that climate/geography, as indicated by studies in different hydrogeologic settings in southern Ontario and uniform settings across a climatic gradient in Europe. Finally, the integration and generalization of these findings to the watershed-regional scale has aided in the transfer of knowledge from the scientist to the manager.

  18. Cost of riparian buffer zones: A comparison of hydrologically adapted site-specific riparian buffers with traditional fixed widths

    NASA Astrophysics Data System (ADS)

    Tiwari, T.; Lundström, J.; Kuglerová, L.; Laudon, H.; Öhman, K.; Ågren, A. M.

    2016-02-01

    Traditional approaches aiming at protecting surface waters from the negative impacts of forestry often focus on retaining fixed width buffer zones around waterways. While this method is relatively simple to design and implement, it has been criticized for ignoring the spatial heterogeneity of biogeochemical processes and biodiversity in the riparian zone. Alternatively, a variable width buffer zone adapted to site-specific hydrological conditions has been suggested to improve the protection of biogeochemical and ecological functions of the riparian zone. However, little is known about the monetary value of maintaining hydrologically adapted buffer zones compared to the traditionally used fixed width ones. In this study, we created a hydrologically adapted buffer zone by identifying wet areas and groundwater discharge hotspots in the riparian zone. The opportunity cost of the hydrologically adapted riparian buffer zones was then compared to that of the fixed width zones in a meso-scale boreal catchment to determine the most economical option of designing riparian buffers. The results show that hydrologically adapted buffer zones were cheaper per hectare than the fixed width ones when comparing the total cost. This was because the hydrologically adapted buffers included more wetlands and low productive forest areas than the fixed widths. As such, the hydrologically adapted buffer zones allows more effective protection of the parts of the riparian zones that are ecologically and biogeochemically important and more sensitive to disturbances without forest landowners incurring any additional cost than fixed width buffers.

  19. IDENTIFICATION EFFICIENCY IN GROUNDWATER ADJACENT TO DITCHES WITHIN CONSTRUCTED RIPARIAN WETLANDS: KANKAKEE WATERSHED, ILLINOIS-INDIANA, U.S.A.

    EPA Science Inventory

    Dual isotope evaluations of NO3 in groundwater adjacent to ditches within constructed riparian wetlands across the Kankakee water-shed may assist the determination of denitrification efficiency. Groundwater sampling indicates the NO3 -N exceeded 10 mg 1-1 in constructed riparian ...

  20. Quantifying the performance of automated GIS-based geomorphological approaches for riparian zone delineation using digital elevation models

    NASA Astrophysics Data System (ADS)

    Fernández, D.; Barquín, J.; Álvarez-Cabria, M.; Peñas, F. J.

    2012-10-01

    Riparian zone delineation is a central issue for managing rivers and adjacent areas; however, criteria used to delineate them are still under debate. The area inundated by a 50-yr flood has been indicated as an optimal hydrological descriptor for riparian areas. This detailed hydrological information is usually only available for populated areas at risk of flooding. In this work we created several floodplain surfaces by means of two different GIS-based geomorphological approaches using digital elevation models (DEMs), in an attempt to find hydrologically meaningful potential riparian zones for river networks at the river basin scale. Objective quantification of the performance of the two geomorphologic models is provided by analysing coinciding and exceeding areas with respect to the 50-yr flood surface in different river geomorphological types.

  1. Water quality dynamics and hydrology in nitrate loaded riparian zones in the Netherlands.

    PubMed

    Hefting, Mariet; Beltman, Boudewijn; Karssenberg, Derek; Rebel, Karin; van Riessen, Mirjam; Spijker, Maarten

    2006-01-01

    Riparian zones are known to function as buffers, reducing non-point source pollution from agricultural land to streams. In the Netherlands, riparian zones are subject to high nitrogen inputs. We combined hydrological, chemical and soil profile data with groundwater modelling to evaluate whether chronically N loaded riparian zones were still mitigating diffuse nitrate fluxes. Hydraulic parameters and water quality were monitored over 2 years in 50 piezometres in a forested and grassland riparian zone. Average nitrate loadings were high in the forested zone with 87 g NO(3)(-)-N m(-2) y(-1) and significantly lower in the grassland zone with 15 g NO(3)(-)-N m(-2) y(-1). Groundwater from a second aquifer diluted the nitrate loaded agricultural runoff. Biological N removal however occurred in both riparian zones, the grassland zone removed about 63% of the incoming nitrate load, whereas in the forested zone clear symptoms of saturation were visible and only 38% of the nitrate load was removed.

  2. Delineating riparian zones for entire river networks using geomorphological criteria

    NASA Astrophysics Data System (ADS)

    Fernández, D.; Barquín, J.; Álvarez-Cabria, M.; Peñas, F. J.

    2012-03-01

    Riparian zone delineation is a central issue for riparian and river ecosystem management, however, criteria used to delineate them are still under debate. The area inundated by a 50-yr flood has been indicated as an optimal hydrological descriptor for riparian areas. This detailed hydrological information is, however, not usually available for entire river corridors, and is only available for populated areas at risk of flooding. One of the requirements for catchment planning is to establish the most appropriate location of zones to conserve or restore riparian buffer strips for whole river networks. This issue could be solved by using geomorphological criteria extracted from Digital Elevation Models. In this work we have explored the adjustment of surfaces developed under two different geomorphological criteria with respect to the flooded area covered by the 50-yr flood, in an attempt to rapidly delineate hydrologically-meaningful riparian zones for entire river networks. The first geomorphological criterion is based on the surface that intersects valley walls at a given number of bankfull depths above the channel (BFDAC), while the second is based on the surface defined by a~threshold value indicating the relative cost of moving from the stream up to the valley, accounting for slope and elevation change (path distance). As the relationship between local geomorphology and 50-yr flood has been suggested to be river-type dependant, we have performed our analyses distinguishing between three river types corresponding with three valley morphologies: open, shallow vee and deep vee valleys (in increasing degree of valley constrainment). Adjustment between the surfaces derived from geomorphological and hydrological criteria has been evaluated using two different methods: one based on exceeding areas (minimum exceeding score) and the other on the similarity among total area values. Both methods have pointed out the same surfaces when looking for those that best match with

  3. Holding onto the Green Zone: A Youth Program for the Study and Stewardship of Community Riparian Areas. Action Guide

    ERIC Educational Resources Information Center

    US Department of the Interior, 2008

    2008-01-01

    Scientists call the land along the edges of a river, stream, or lake a riparian zone. In this guide, riparian zone will be called the Green Zone. Riparian zones make up only a small part of land in the United States. But they are very important. They protect water quality and quantity, supply food and shelter for fish and wildlife, and provide…

  4. META-ANALYSIS OF NITROGEN REMOVAL IN RIPARIAN BUFFERS

    EPA Science Inventory

    Riparian buffer zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Riparian buffer width may be positively related to nitrogen removal effectiveness by influencing nitrog...

  5. Influence of gully erosion control on amphibian and reptile communities within riparian zones of channelized streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian zones of streams in northern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Gully erosion is the most severe form of erosion and has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used c...

  6. The hydrology of riparian buffer zones; two case studies in an ephemeral and a perennial stream

    NASA Astrophysics Data System (ADS)

    Rassam, David W.; Fellows, Christine S.; De Hayr, Robert; Hunter, Heather; Bloesch, Philip

    2006-06-01

    Riparian zones can provide a protective buffer between streams and adjacent land-based activities by removing nitrate from shallow groundwater flowing through them. Hydrological factors are an important influence on the effectiveness of riparian buffer zones in reducing pollutant loads delivered to streams. In this paper, we present results from a study of the hydrology of two riparian buffers belonging to an ephemeral and a perennial stream, which are part of a research project to study nitrogen transport and transformation processes in shallow groundwater in South-East Queensland, Australia. The investigation at the ephemeral site has shown that a shallow perched water table forms shortly after stream flow commences as a result of lateral flow from the stream to floodplain; it resides within the carbon-rich root zone and drains off after stream flow ceases. The low head gradient of 1% results in a low flow rate of about 6 cm/day along the floodplain, slow enough to allow effective removal of nitrate via denitrification to occur. The investigation at the perennial site has shown that water table dynamics within the floodplain are dissociated from the up-slope area except during over-bank flood events. During non-event conditions, there is low streamward gradient that results in a base flow component to the stream; the water table depth is about 3.5 m, hence missing most of the carbon-rich soils located close to the soil surface. During flood events, a reverse gradient towards the floodplain is formed; the streamward gradient is re-established after the flood wave passes. The water table fluctuates between 1.8 and 3.5 m under these conditions thus having a higher chance of interacting with more active floodplain sediments. Water stored in the floodplain has a residence time of 2-10 days, providing an opportunity for denitrification to reduce nitrate concentrations prior to water draining back to the stream.

  7. Relationship of wooded riparian zones and runoff potential to fish community composition in agricultural streams

    USGS Publications Warehouse

    Stauffer, J.C.; Goldstein, R.M.; Newman, R.M.

    2000-01-01

    The relationship of fish community composition to riparian cover and runoff potential was investigated in 20 streams in the agricultural Minnesota River Basin during the summer of 1997. Analysis of variance indicated significant differences in fish community composition due to both riparian cover (wooded versus open) and runoff potential (high or low). Streams with wooded riparian zones had higher index of biological integrity (IBI) scores, species richness, diversity, and percentages of benthic insectivores and herbivores than streams with open riparian zones. Streams with low runoff potential had higher IBI scores and species richness than streams with high runoff potential. The riparian cover and runoff potential interaction was marginally significant with respect to IBI scores and species richness, suggesting a weak interaction between the two factors. Although both factors were important, riparian cover influenced fish community composition more than runoff potential in these streams, indicating that local factors (close to the stream) dominated landscape- or basin-level factors.

  8. Denitrification Potential, Root Biomass and Organic Matter in Degraded and Restored Urban Riparian Zones

    EPA Science Inventory

    Hydrologic changes associated with urbanization often lead to lower water tables and drier, more aerobic soils in riparian zones. These changes reduce the potential for denitrification, an anaerobic microbial process that converts nitrate, a common water pollutant, into nitroge...

  9. Denitrification Potential, Root Biomass, and Organic Matter in Degraded and Restored Urban Riparian Zones

    EPA Science Inventory

    Hydrologic changes associated with urbanization often lead to lower water tables and drier, more aerobic soils in riparian zones. These changes reduce the potential for denitrification, an anaerobic microbial process that converts nitrate, a common water pollutant, into nitrogen...

  10. Hillslope versus riparian zone runoff contributions in headwater catchments: A multi-watershed comparison

    NASA Astrophysics Data System (ADS)

    McGlynn, B. L.; McGlynn, B. L.; McDonnell, J. J.; Hooper, R. P.; Shanley, J. B.; Hjerdt, K. N.; Hjerdt, K. N.

    2001-12-01

    It is often assumed that hillslope and riparian areas constitute the two most important and identifiable landscape units contributing to catchment runoff in upland humid catchments. Nevertheless, the relative amount and timing of hillslope versus riparian contributions to stormflow are poorly understood across different watersheds. We quantified the contributions of hillslopes and riparian zones to stormflow using physical, chemical, and isotopic techniques across 3 diverse ({ ~}15 ha) headwater catchments: a highly responsive steep wet watershed (Maimai, New Zealand), a moderately steep snowmelt dominated watershed (Sleepers, River, VT), and at a highly seasonal relatively low relief watershed (Panola Mt., Georgia). We monitored catchment runoff, internal hydrological response, and isotopic and solute dynamics for discrete riparian and hillslope zones within each catchment. Monitored catchment positions, including hillslope trenches at Maimai and Panola, were used to characterize directly, the hydrologic response and source water signatures for hillslope zones and riparian zones. We also examined the spatial and temporal source components of catchment stormflow using 3-component mass balance hydrograph separation techniques. At Maimai, NZ we found that hillslope runoff comprised 47-55% of total runoff during a 70 mm event. Despite the large amount of subsurface hillslope runoff in total catchment stormflow, riparian and channel zones accounted for 28% out of 29% of the total new water measured catchment runoff. Riparian water dominated the storm hydrograph composition early in the event, although hillslope water reached the catchment outlet soon after hillslope water tables were developed. Preliminary results for Sleepers River, VT and Panola Mountain, GA indicate that the timing and relative proportion of hillslope water in catchment runoff is later and smaller than at Maimai. Our multi-catchment comparison suggests that the ratio of the riparian reservoir to the

  11. SOIL NITROUS OXIDE, NITRIC OXIDE, AND AMMONIA EMISSIONS FROM A RECOVERING RIPARIAN ECOSYSTEM IN SOUTHERN APPALACHIA

    EPA Science Inventory

    The paper presents two years of seasonal nitric oxide, ammonia, and nitrous oxide trace gas fluxes measured in a recovering riparian zone with cattle excluded and in an adjacent riparian zone grazed by cattle. In the recovering riparian zone, average nitric oxide, ammonia, and ni...

  12. The on-ranch economics of riparian zone cattle grazing management.

    PubMed

    Unterschultz, James R; Miller, Jamie; Boxall, Peter C

    2004-05-01

    A simulation model of a cattle ranch based in southern Alberta, Canada was developed to evaluate the on-ranch economics of adopting different grazing management strategies to improve riparian grazing capacity in natural grass rangeland. Under low-cost scenarios, there are positive economic incentives to adopt strategies to maintain riparian zones that already have high grazing capacity. However, riparian zones that have declined to moderate or low grazing capacity may require additional economic incentives to encourage ranches to adopt more costly management strategies to improve the grazing capacity. The economic incentives to adopt costly management strategies are highly sensitive to the size and shape of the riparian zone and rates of grazing capacity decline or improvement.

  13. [Distribution pattern of rare plants along riparian zone and its implication for conservation in Shennongjia area].

    PubMed

    Jiang, Mingxi; Deng, Hongbing; Cai, Qinghua

    2002-11-01

    Due to the importance of riparian zone in maintaining and protecting regional biodiversity, more and more ecologists paid their attentions to riparian zone, and had been aware of the important effects of riparian zone in basic study and practical management. In this study, forty sampling belts (10 m x 100 m) parallel to the bank of Xiangxi River at different elevations in Shennongjia area were selected to investigate the riparian vegetation and rare plants. Fourteen species of rare plants were found in riparian zone, accounting for 42.4% of total rare plant species in Shennongjia area. The main distribution range of the fourteen rare plant species was the mixed evergreen and deciduous broadleaved forest at elevation of 1200-1800 m, where species diversity of plant community was the maximum at the moderate elevation. Fourteen rare plant species could be divided into three groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation group. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out the important function of riparian zone on rare plant species protection.

  14. Sedimentation and associated trace metal enrichment in the riparian zone of the Three Gorges Reservoir, China.

    PubMed

    Tang, Qiang; Bao, Yuhai; He, Xiubin; Zhou, Huaidong; Cao, Zhijing; Gao, Peng; Zhong, Ronghua; Hu, Yunhua; Zhang, Xinbao

    2014-05-01

    Impoundment of the Three Gorges Reservoir has created an artificial riparian zone with a vertical height of 30 m and a total area of 349 km(2), which has been subjected to seasonal inundation and exposure due to regular reservoir impoundment and the occurrence of natural floods. The significant alteration of hydrologic regime has caused numerous environmental changes. The present study investigated the magnitude and spatial pattern of sedimentation and metal enrichment in a typical section of the riparian zone, composed of bench terraces with previous agricultural land uses, and explored their links to the changed hydrologic regime. In particular, we measured the total sediment depths and collected surface riparian sediments and down-profile sectioned riparian soils (at 5 cm intervals) for trace metal determination. Our analysis showed that the annual average sedimentation rates varied from 0.5 to 10 cm·yr(-1) and they decreased significantly with increasing elevation. This lateral distribution was principally attributed to seasonal variations in water levels and suspended sediment concentrations. Enriched concentrations of trace metals were found both in the riparian sediments and soils, but they were generally higher in the riparian sediments than in riparian soils and followed a similar lateral decreasing trend. Metal contamination assessment showed that the riparian sediments were slightly contaminated by Ni, Zn, and Pb, moderately contaminated by Cu, and moderately to strongly contaminated by Cd; while riparian soils were slightly contaminated by As, and moderately contaminated by Cd. Trace metal enrichment in the riparian sediments may be attributed to external input of contaminated sediments produced from upstream anthropogenic sources and chemical adsorption from dissolved fractions during pure sediment mobilization and after sink for a prolonged flooding period due to reservoir impoundment.

  15. Sedimentation and associated trace metal enrichment in the riparian zone of the Three Gorges Reservoir, China.

    PubMed

    Tang, Qiang; Bao, Yuhai; He, Xiubin; Zhou, Huaidong; Cao, Zhijing; Gao, Peng; Zhong, Ronghua; Hu, Yunhua; Zhang, Xinbao

    2014-05-01

    Impoundment of the Three Gorges Reservoir has created an artificial riparian zone with a vertical height of 30 m and a total area of 349 km(2), which has been subjected to seasonal inundation and exposure due to regular reservoir impoundment and the occurrence of natural floods. The significant alteration of hydrologic regime has caused numerous environmental changes. The present study investigated the magnitude and spatial pattern of sedimentation and metal enrichment in a typical section of the riparian zone, composed of bench terraces with previous agricultural land uses, and explored their links to the changed hydrologic regime. In particular, we measured the total sediment depths and collected surface riparian sediments and down-profile sectioned riparian soils (at 5 cm intervals) for trace metal determination. Our analysis showed that the annual average sedimentation rates varied from 0.5 to 10 cm·yr(-1) and they decreased significantly with increasing elevation. This lateral distribution was principally attributed to seasonal variations in water levels and suspended sediment concentrations. Enriched concentrations of trace metals were found both in the riparian sediments and soils, but they were generally higher in the riparian sediments than in riparian soils and followed a similar lateral decreasing trend. Metal contamination assessment showed that the riparian sediments were slightly contaminated by Ni, Zn, and Pb, moderately contaminated by Cu, and moderately to strongly contaminated by Cd; while riparian soils were slightly contaminated by As, and moderately contaminated by Cd. Trace metal enrichment in the riparian sediments may be attributed to external input of contaminated sediments produced from upstream anthropogenic sources and chemical adsorption from dissolved fractions during pure sediment mobilization and after sink for a prolonged flooding period due to reservoir impoundment. PMID:24561931

  16. Riparian zone flowpath dynamics during snowmelt in a small headwater catchment

    USGS Publications Warehouse

    McGlynn, B.L.; McDonnell, Jeffery J.; Shanley, J.B.; Kendall, C.

    1999-01-01

    The hydrology of the near-stream riparian zone in upland humid catchments is poorly understood. We examined the spatial and temporal aspects of riparian flowpaths during snowmelt in a headwater catchment within the Sleepers River catchment in northern Vermont. A transect of 15 piezometers was sampled for Ca, Si, DOC, other major cations, and ??18O. Daily piezometric head values reflected variations in the stream hydrograph induced by melt and rainfall. The riparian zone exhibited strong upward discharge gradients. An impeding layer was identified between the till and surficial organic soil. Water solute concentrations increased toward the stream throughout the melt. Ca concentrations increased with depth and DOC concentrations decreased with depth. The concentrations of Ca in all piezometers were lower during active snowmelt than during post-melt low flow. Ca data suggest snowmelt infiltration to depth; however, only upslope piezometers exhibited snowmelt infiltration and consequent low ??18O values, while ??18O values varied less than 0.5% in the deep riparian piezometers throughout the study period. Ca and ??18O values in upslope piezometers during low streamflow were comparable to Ca and ??18O in riparian piezometers during high streamflow. The upland water Ca and ??18O may explain the deep riparian Ca dilution and consistent ??18O composition. The temporal pattern in Ca and ??18O indicate that upland water moves to the stream via a lateral displacement mechanism that is enhanced by the presence of distinct soil/textural layers. Snowmelt thus initiates the flux of pre-melt, low Ca upland water to depth in the riparian zone, but itself does not appear at depth in the riparian zone during spring melt. This is despite the coincident response of upland groundwater and stream discharge.The hydrology of the near-stream riparian zone in upland humid catchments is poorly understood. We examined the spatial and temporal aspects of riparian flowpaths during snowmelt in a

  17. Subtropical reservoir shorelines have reduced plant species and functional richness compared with adjacent riparian wetlands

    NASA Astrophysics Data System (ADS)

    Liu, Wenzhi; Liu, Guihua; Liu, Hui; Song, Yu; Zhang, Quanfa

    2013-12-01

    Dam construction has large negative effects on biodiversity in river and riparian ecosystems worldwide. This study aimed to determine whether reservoir shorelines had lower plant species diversity and functional diversity than unregulated or lightly regulated riparian wetlands and to examine the responses of plant diversity and functional traits to reservoir shoreline environmental gradients. We surveyed 146, 44, and 67 plots on reservoir shorelines and in mainstem and tributary riparian wetlands, respectively, in a subtropical river-reservoir system. Species richness, functional richness, evenness, and divergence were calculated to reflect the species and functional diversity of plant communities. Environmental factors including elevation above water level, slope, landform type, substrate, disturbance, and cover were measured. The results showed that both species and functional richness were significantly lower on reservoir shorelines than in riparian wetlands. The relative species number of clonal plants and relative cover of annual plants were both negatively related to slope and elevation. Structural equation modeling and other statistical analyses indicated that most environmental factors had significant effects on species and functional richness on reservoir shorelines but had no significant effect on functional evenness and divergence. Our findings suggest that reservoir shoreline wetlands formed by damming rivers and inundating pre-existing riparian wetlands can be a biodiversity coldspot in regulated rivers at the plot level. Topographic factors are important in determining the plant diversity and vegetation establishment on reservoir shorelines in the Yangtze River basin.

  18. Behavior and distribution of cattle grazing riparian zones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to study cattle site use and behavior in riparian pastures so that the nature of use by livestock can be determined and potential ecosystem impacts can be scientifically evaluated. Through the course of this study, we will employ high resolution GPS trackers to exam...

  19. Riparian buffer zones as pesticide filters of no-till crops.

    PubMed

    Aguiar, Terencio R; Bortolozo, F R; Hansel, F A; Rasera, K; Ferreira, M T

    2015-07-01

    Several studies have pointed to the potential benefits of riparian vegetation as buffer zones for agricultural and industrial pollutants harmful to aquatic ecosystems. However, other studies have called into question its use as an ecological filter, questioning the widths and conditions for which they are effective as a filter. In this work, we have investigated the buffering capacity of the riparian one to retain pesticides in the water-saturated zone, on 27 sites composed by riparian buffer zones with different vegetation structure (woody, shrubs, or grass vegetation) and width (12, 36, and 60 m). Five pesticides were analyzed. The effectiveness of the filtering was largely influenced by the width and vegetation type of the buffer zone. In general, decreasing pesticide removal followed in this order wood > shrubs > grass. The 60 m woody buffer zone was the most effective in the removal of all the pesticides. Only atrazine was detected in this case (0.3 μg L(-1)). Furthermore, a linear correlation (R (2) > 0.97) was observed in their removal for all compounds and buffer zones studied. Thus, preserving the woody vegetation in the riparian zone is important for watershed management and groundwater quality in the no-tillage system in temperate climate.

  20. Riparian buffer zones as pesticide filters of no-till crops.

    PubMed

    Aguiar, Terencio R; Bortolozo, F R; Hansel, F A; Rasera, K; Ferreira, M T

    2015-07-01

    Several studies have pointed to the potential benefits of riparian vegetation as buffer zones for agricultural and industrial pollutants harmful to aquatic ecosystems. However, other studies have called into question its use as an ecological filter, questioning the widths and conditions for which they are effective as a filter. In this work, we have investigated the buffering capacity of the riparian one to retain pesticides in the water-saturated zone, on 27 sites composed by riparian buffer zones with different vegetation structure (woody, shrubs, or grass vegetation) and width (12, 36, and 60 m). Five pesticides were analyzed. The effectiveness of the filtering was largely influenced by the width and vegetation type of the buffer zone. In general, decreasing pesticide removal followed in this order wood > shrubs > grass. The 60 m woody buffer zone was the most effective in the removal of all the pesticides. Only atrazine was detected in this case (0.3 μg L(-1)). Furthermore, a linear correlation (R (2) > 0.97) was observed in their removal for all compounds and buffer zones studied. Thus, preserving the woody vegetation in the riparian zone is important for watershed management and groundwater quality in the no-tillage system in temperate climate. PMID:25744820

  1. Stream-upland connectivity through the riparian zone: lessons learned and future research needs (Invited)

    NASA Astrophysics Data System (ADS)

    Vidon, P.

    2013-12-01

    Riparian zones act both as a conduit and a buffer for water and solutes as they transit from the upland environment to the stream. However, the traditional view of riparian hydrological functioning whereby the flow of water and solutes is generally from upland to stream has recently been challenged in some settings. For instance, in large outwash floodplains of the US Midwest, streams and rivers can have a dominant influence on riparian water table dynamics and associated biogeochemistry (nitrogen, phosphorus, carbon, mercury). In glacial till settings of the US Northeast, stream meander curvature has been shown to have a large impact on near stream zone hydrology and biogeochemistry. In the US southeast, stream restoration practices have far reaching impacts in the near stream zone. This talk will provide a framework to conceptualize riparian function as a function of stream channel morphology and landscape hydrogeomorphic characteristics. The implications of this work on riparian zone hydrology and biogeochemistry within the context of stream restoration and watershed management will be discussed along with key research needs for years to come.

  2. Microbial Community Structure Across a Wastewater-Impacted Riparian Buffer Zone in the Southeastern Coastal Plain

    PubMed Central

    Ducey, T.F.; Johnson, P.R.; Shriner, A.D.; Matheny, T.A.; Hunt, P.G.

    2013-01-01

    Riparian buffer zones are important for both natural and developed ecosystems throughout the world because of their ability to retain nutrients, prevent soil erosion, protect aquatic environments from excessive sedimentation, and filter pollutants. Despite their importance, the microbial community structures of riparian buffer zones remains poorly defined. Our objectives for this study were twofold: first, to characterize the microbial populations found in riparian buffer zone soils; and second, to determine if microbial community structure could be linked to denitrification enzyme activity (DEA). To achieve these objectives, we investigated the microbial populations of a riparian buffer zone located downslope of a pasture irrigated with swine lagoon effluent, utilizing DNA sequencing of the 16S rDNA, DEA, and quantitative PCR (qPCR) of the denitrification genes nirK, nirS, and nosZ. Clone libraries of the 16S rDNA gene were generated from each of twelve sites across the riparian buffer with a total of 986 partial sequences grouped into 654 operational taxonomic units (OTUs). The Proteobacteria were the dominant group (49.8% of all OTUs), with the Acidobacteria also well represented (19.57% of all OTUs). Analysis of qPCR results identified spatial relationships between soil series, site location, and gene abundance, which could be used to infer both incomplete and total DEA rates. PMID:23894260

  3. Mercury dynamics in groundwater across three distinct riparian zone types of the US Midwest.

    PubMed

    Vidon, Philippe G; Mitchell, Carl P J; Jacinthe, Pierre-André; Baker, Matthew E; Liu, Xiaoqiang; Fisher, Katelin R

    2013-10-01

    Although the intense biogeochemical gradients present in riparian zones have the potential to affect mercury (Hg) cycling, Hg dynamics in riparian zones has received relatively little attention in the literature. Our study investigated groundwater filtered total mercury (THg) and methylmercury (MeHg) dynamics in three riparian zones with contrasting hydrogeomorphic (HGM) characteristics (till, alluvium, outwash) in the US Midwest. Despite high Hg deposition rates (>16 μg m(-2)) in the region, median THg (<1.05 ng L(-1)) and MeHg (<0.05 ng L(-1)) concentrations were low at the study sites. Methylmercury concentrations were significantly (p < 0.05) correlated to THg (R = 0.82), temperature (R = 0.55), and dissolved organic carbon (DOC) (R = 0.62). THg also correlated with groundwater DOC (R = 0.59). The proportion of MeHg in THg (%MeHg) was significantly correlated to temperature (R = 0.58) and MeHg (R = 0.50). Results suggest that HGM characteristics, the presence of tile drains, and the propensity for overbank flooding at a riparian site determined the extent to which stream water Hg concentrations influenced riparian groundwater Hg levels or vice versa. Differences in hydrogeomorphic characteristics between sites did not translate however in significant differences in groundwater MeHg or %MeHg. Overall, widespread Hg contamination in the most common riparian hydrogeomorphic types of the US Midwest is unlikely to be a major concern. However, for frequently flooded riparian zones located downstream from a potentially large source of Hg (e.g., concentrated urban development), Hg concentrations are likely to be higher than at other sites.

  4. Ground Water Redox Zonation near La Pine, Oregon: Relation to River Position within the Aquifer-Riparian Zone Continuum

    USGS Publications Warehouse

    Hinkle, Stephen R.; Morgan, David S.; Orzol, Leonard L.; Polette, Danial J.

    2007-01-01

    peripheral zones, whereas older, typically more reduced ground water tends to discharge closer to the center of the river corridor. Such distributions of redox state reflect ground-water movement and geochemical evolution at the aquifer-scale. Redox state of ground water undergoes additional modification as ground water nears discharge points in or adjacent to rivers, where riparian zone processes can be important. Lateral erosion of river systems away from the center of the flood plain can decrease or even eliminate interactions between ground water and reducing riparian zone sediments. Thus, ground water redox patterns in near-river sediments appear to reflect the position of a river within the riparian zone/aquifer continuum. Spatial heterogeneity of redox conditions near the river/aquifer boundary (that is, near the riverbed) makes it difficult to extrapolate transect-scale findings to a precise delineation of the oxic-suboxic boundary in the near-river environment of the entire study area. However, the understanding of relations between near-river redox state and proximity to riparian zone edges provides a basis for applying these results to the study-area scale, and could help guide management efforts such as nitrogen-reduction actions or establishment of Total Maximum Daily Load criteria. Coupling the ground-water redox-based understanding of river vulnerability with ground-water particle-tracking-based characterization of connections between upgradient recharge areas and receiving rivers demonstrates one means of linking effects of potential nitrate loads at the beginning of ground-water flow paths with river vulnerability.

  5. Groundwater flow path dynamics and nitrogen transport potential in the riparian zone of an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Williams, Mark R.; Buda, Anthony R.; Elliott, Herschel A.; Hamlett, James; Boyer, Elizabeth W.; Schmidt, John P.

    2014-04-01

    Shallow groundwater dynamics play a critical role in determining the chemistry and movement of nitrogen (N) in the riparian zone. In this study, we characterized N concentration variability and hydrologic transport pathways in shallow groundwater draining areas of a riparian area with and without emergent groundwater seeps. The study was conducted in FD36, an agricultural headwater catchment in the Ridge and Valley physiographic region of central Pennsylvania, USA. Three seep and adjacent non-seep areas were each instrumented with a field of 40 piezometers installed in a grid pattern (1.5-m spacing) at both 20- and 60-cm depths. Piezometers were monitored seasonally for approximately two years (October 2010-May 2012). Results showed that hydraulic head within seep areas was variable and some regions exhibited upward vertical hydraulic gradients of 0.18-0.27. Non-seep areas were characterized by uniform hydraulic head levels and were relatively hydrostatic. Nitrate-N (NO3-N) concentrations in seep areas were significantly greater than those in the non-seep areas at two of the three study sites. A two-component mixing model using chloride as a conservative tracer indicated that shallow groundwater in seep areas was primarily (53-75%) comprised of water from a shallow fractured aquifer, which had elevated NO3-N concentrations (5.7 mg L-1). Shallow groundwater in non-seep areas, however, was comprised (58-82%) of perched water on top of the fragipan that was likely recharged locally in the riparian zone and had low NO3-N concentrations (0.6 mg L-1). Higher NO3-N concentrations, variable hydraulic head, and groundwater emergence onto the land surface in seep areas provided evidence for preferential flow paths as an important conduit for water and N movement in these areas of the riparian zone. We conclude that the potential for N delivery to the stream in FD36 was much greater from seep areas compared to non-seep areas. Targeted management of seeps should be a priority

  6. Impact of water troughs on cattle use of riparian zones in the Georgia Piedmont in the United States.

    PubMed

    Franklin, D H; Cabrera, M L; Byers, H L; Matthews, M K; Andrae, J G; Radcliffe, D E; McCann, M A; Kuykendall, H A; Hoveland, C S; Calvert, V H

    2009-06-01

    Cattle use of riparian areas may lead to stream water contamination with nutrients, pathogens, and sediments. Providing alternative water away from the stream may reduce the amount of time cattle spend near streams and therefore reduce contamination. We conducted this study to 1) evaluate the effect of providing water troughs outside of the riparian zones on the amount of time cattle spend in riparian zones, and 2) evaluate if environmental factors such as temperature and humidity affect the impact of water trough availability on the amount of time cattle spend within riparian and nonriparian locations. Global positioning system (GPS) collars were used to document cow locations every 5 min in 2 mixed tall fescue/common bermuda-grass pastures of the Georgia Piedmont in the United States. We found that when the temperature and humidity index (THI) ranged between 62 and 72, providing cattle with water troughs outside of riparian zones tended to decrease time cattle spent in riparian zones by 63% (52 min x d(-1); P = 0.11). When THI ranged between 72 and 84, nonriparian water availability did not have a significant impact on the amount of time cattle spent in the riparian zone or in riparian shade. These results suggest that water troughs placed away from unfenced streams may improve water quality by reducing the amount of time cattle spend in riparian zones when environmental conditions as evaluated by THI are not stressful.

  7. EVALUATION OF THE EFFECTIVENESS OF RIPARIAN ZONE RESTORATION IN THE SOUTHERN APPALACHIANS BY ASSESSING SOIL MICROBIAL POPULATIONS

    EPA Science Inventory

    Microbial biomass, nitrifiers and denitrifiers in surface soil (0?10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: (1) a degraded (+N) riparian zone with continued compaction, vegetation rem...

  8. [Characteristics of soil denitrifying enzyme activity in riparian zones with different land use types in Chongming Island, Shanghai of China].

    PubMed

    Chen, Gang-Liang; Li, Jian-Hua; Yang, Chang-Ming

    2013-10-01

    By using acetylene inhibition method, this paper studied the soil denitrifying enzyme activity (DEA) and its affecting factors in the riparian zone with different land use types (cropland riparian, forested riparian, and grassy riparian zones) in Chongming Island, Shanghai of China. The riparian soil DEA was (0.69 +/- 0.11)--(134.93 +/- 33.72) microg N x kg(-1) x h(-1), which differed obviously among different land types, with a decreasing trend of forested riparian zone > cropland riparian zone > grassy riparian zone. The soil DEA was significantly (P < 0.05) higher in 0-10 cm in 10-30, 30-50, and 50-70 cm layers. There were significant positive relationships between soil DEA and soil TOC, TN, and NO(3-)-N (P < 0.01). Land use change mainly altered the soil natural structure and soil physical and chemical properties, decreased the accumulation of soil organic carbon, and affected the soil nitrogen transformation, and thus, inhibited the occurrence of riparian soil denitrification.

  9. Influence of riparian seepage zones on nitrate variability in two agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian seepage zones are one of the primary pathways of groundwater transport to headwater streams. While seeps have been recognized for their contributions to streamflow, there is little information on how seeps affect stream water quality. The objective of this study was to examine the influence...

  10. [Pilot-scale study on riparian mixed plant zones treating polluted river water].

    PubMed

    Li, Rui-hua; Guan, Yun-tao; He, Miao; Hu, Hong-yin; Jiang, Zhan-peng

    2006-04-01

    The polluted river water is treated with pilot-scale riparian zones of no aquatic plant, Vetiveria zizanioides + submerged plants, and weed+ Typha angustifolia L. + Phragmites communis. It is shown that the vegetation water zones are better than the no vegetation water zone and Vetiveria zizanioides + submerged plants zone is the best in improving water quality. The average removals of the Vetiveria zizanioides + submerged plant zone is 43.5% COD, 71.1% ammonia and 69.3% total phosphorus respectively. The dissolved oxygen (DO) and temperature of effluents from the three water zones are also investigated. It shows that DO of effluent from the vegetation zones are more stable than that of effluent from the no vegetation zone, and the temperature of the effluent from the vegetation zones are lower than that from the no vegetation zones. The submerged plants have special role in water quality improvement, and should be studied further. PMID:16767981

  11. Implications of hydrologic connectivity between hillslopes and riparian zones on streamflow composition.

    PubMed

    von Freyberg, Jana; Radny, Dirk; Gall, Heather E; Schirmer, Mario

    2014-11-15

    Hydrological responses in mountainous headwater catchments are often highly non-linear with a distinct threshold-related behavior, which is associated to steep hillslopes, shallow soils and strong climatic variability. A holistic understanding of the dominant physical processes that control streamflow generation and non-linearity is required in order to assess potential negative effects of agricultural land use and water management in those areas. Therefore, streamflow generation in a small pre-Alpine headwater catchment (Upper Rietholzbach (URHB), ~1km(2)) was analyzed over a 2-year period by means of rainfall-response analysis and water quality data under explicit consideration of the joint behaviors of climate forcing and shallow groundwater dynamics. The runoff coefficients indicate that only a small fraction of the total catchment area (1-26%) generates streamflow during rainfall events. Hereby, the valley bottom areas (riparian zones) were the most important event-water source whereas only the lower parts of the hillslopes became hydrologically connected to the river network with higher antecedent moisture conditions. However, a distinct threshold-like behavior could not be observed, suggesting a more continuous shift from a riparian-zone to a more hillslope-dominated streamflow hydrograph. Regular manure application on the hillslopes in combinations with lateral hillslope groundwater flux and long groundwater residence times in the riparian zones resulted in a higher mineralization (e.g., total phosphorous) and significant denitrification in the valley bottom area. Despite the important role of the riparian zones for event-flow generation in the URHB, their nutrient buffer capacity is expected to be small due to the low permeability of the local subsurface material. The findings of this integrated analysis are summarized in a conceptual framework describing the hydrological functioning of hillslopes and riparian zones in the URHB. PMID:25106837

  12. Implications of hydrologic connectivity between hillslopes and riparian zones on streamflow composition

    NASA Astrophysics Data System (ADS)

    von Freyberg, Jana; Radny, Dirk; Gall, Heather E.; Schirmer, Mario

    2014-11-01

    Hydrological responses in mountainous headwater catchments are often highly non-linear with a distinct threshold-related behavior, which is associated to steep hillslopes, shallow soils and strong climatic variability. A holistic understanding of the dominant physical processes that control streamflow generation and non-linearity is required in order to assess potential negative effects of agricultural land use and water management in those areas. Therefore, streamflow generation in a small pre-Alpine headwater catchment (Upper Rietholzbach (URHB), ~ 1 km2) was analyzed over a 2-year period by means of rainfall-response analysis and water quality data under explicit consideration of the joint behaviors of climate forcing and shallow groundwater dynamics. The runoff coefficients indicate that only a small fraction of the total catchment area (1-26%) generates streamflow during rainfall events. Hereby, the valley bottom areas (riparian zones) were the most important event-water source whereas only the lower parts of the hillslopes became hydrologically connected to the river network with higher antecedent moisture conditions. However, a distinct threshold-like behavior could not be observed, suggesting a more continuous shift from a riparian-zone to a more hillslope-dominated streamflow hydrograph. Regular manure application on the hillslopes in combinations with lateral hillslope groundwater flux and long groundwater residence times in the riparian zones resulted in a higher mineralization (e.g., total phosphorous) and significant denitrification in the valley bottom area. Despite the important role of the riparian zones for event-flow generation in the URHB, their nutrient buffer capacity is expected to be small due to the low permeability of the local subsurface material. The findings of this integrated analysis are summarized in a conceptual framework describing the hydrological functioning of hillslopes and riparian zones in the URHB.

  13. The role of near-stream riparian zones in the hydrology of steep upland catchments

    USGS Publications Warehouse

    McDonnell, Jeffery J.; McGlynn, B.L.; Kendall, K.; Shanley, J.; Kendall, C.

    1998-01-01

    Surface and subsurface waters were monitored and sampled at various topographic positions in a 40.5-ha headwater catchment to test several hypotheses of runoff generation and stream chemical and isotopic evolution during snowmelt. Transmissivity feedback was observed on the hillslopes during the melt period. Groundwater levels and stream DOC were highly correlated with stream discharge. Hysteresis in the groundwater-streamflow relation suggests that localized water flux from the riparian areas controlled the rising limb and main peak response of the melt hydrograph, whilst hillslope drainage controlled the timing and volume of the falling limb. Lateral flow from upslope positions was detected in the riparian zone.

  14. Nitrous oxide emission and denitrification in chronically nitrate-loaded riparian buffer zones.

    PubMed

    Hefting, Mariet M; Bobbink, Roland; de Caluwe, Hannie

    2003-01-01

    Riparian buffer zones are known to reduce diffuse N pollution of streams by removing and modifying N from agricultural runoff. Denitrification, often identified as the key N removal process, is also considered as a major source of the greenhouse gas nitrous oxide (N2O). The risks of high N2O emissions during nitrate mitigation and the environmental controls of emissions have been examined in relatively few riparian zones and the interactions between controls and emissions are still poorly understood. Our objectives were to assess the rates of N2O emission from riparian buffer zones that receive large loads of nitrate, and to evaluate various factors that are purported to control N emissions. Denitrification, nitrification, and N2O emissions were measured seasonally in grassland and forested buffer zones along first-order streams in The Netherlands. Lateral nitrate loading rates were high, up to 470 g N m(-2) yr(-1). Nitrogen process rates were determined using flux chamber measurements and incubation experiments. Nitrous oxide emissions were found to be significantly higher in the forested (20 kg N ha(-1) yr(-1)) compared with the grassland buffer zone (2-4 kg N ha(-1) yr(-1)), whereas denitrification rates were not significantly different. Higher rates of N2O emissions in the forested buffer zone were associated with higher nitrate concentrations in the ground water. We conclude that N transformation by nitrate-loaded buffer zones results in a significant increase of greenhouse gas emission. Considerable N2O fluxes measured in this study indicate that Intergovernmental Panel on Climate Change methodologies for quantifying indirect N2O emissions have to distinguish between agricultural uplands and riparian buffer zones in landscapes receiving large N inputs. PMID:12931872

  15. Riparian zones as havens for exotic plant species in the central grasslands

    USGS Publications Warehouse

    Stohlgren, T.J.; Bull, K.A.; Otsuki, Y.; Villa, C.A.; Lee, M.

    1998-01-01

    In the Central Grasslands of the United States, we hypothesized that riparian zones high in soil fertility would contain more exotic plant species than upland areas of low soil fertility. Our alternate hypothesis was that riparian zones high in native plant species richness and cover would monopolize available resources and resist invasion by exotic species. We gathered nested-scale vegetation data from 40 1 m2subplots (nested in four 1000 m2 plots) in both riparian and upland sites at four study areas in Colorado, Wyoming, and South Dakota (a total of 320 1 m2subplots and 32 1000 m2 plots). At the 1 m2 scale, mean foliar cover of native species was significantly greater (P < 0.001) in riparian zones (36.6% ?? 1.7%) compared to upland sites (28.7% ?? 1.5%), but at this small scale there were no consistent patterns of native and exotic species richness among the four management areas. Mean exotic species cover was slightly higher in upland sites compared to riparian sites (9.0% ?? 3.8% versus 8.2% ?? 3.0% cover). However, mean exotic species richness and cover were greater in the riparian zones than upland sites in three of four management areas. At the 1000 m2 scale, mean exotic species richness was also significantly greater (P < 0.05) in riparian zones (7.8 ?? 1.0 species) compared to upland sites (4.8 ?? 1.0 species) despite the heavy invasion of one upland site. For all 32 plots combined, 21% of the variance in exotic species richness was explained by positive relationships with soil % silt (t = 1.7, P = 0.09) and total foliar cover (t = 2.4, P = 0.02). Likewise, 26% of the variance in exotic species cover (log10 cover) was explained by positive relationships with soil % silt (t = 2.3, P = 0.03) and total plant species richness (t = 2.4, P = 0.02). At landscape scales (four 1000 m2 plots per type combined), total foliar cover was significantly and positively correlated with exotic species richness (r = 0.73, P < 0.05) and cover (r = 0.74, P < 0.05). Exotic

  16. Holding onto the Green Zone: A Youth Program for the Study and Stewardship of Community Riparian Areas. Leader Guide

    ERIC Educational Resources Information Center

    Reilly, Kate; Wooster, Betsy

    2008-01-01

    Riparian ecosystems are an exciting and dynamic subject for study. These areas are valuable lands and important wildlife habitats, and they contribute greatly to the environmental health of an area. Definitions for the term "riparian" vary, but in this curriculum, the land called the "Green Zone" lies between flowing water and upland ecosystems.…

  17. Groundwater Dynamics and Evapotranspiration Processes from Gobi Desert to Riparian Zone in Water-Limited Environment

    NASA Astrophysics Data System (ADS)

    Wang, P.; Pozdniakov, S. P.; Grinevsky, S. O.; Niu, G. Y.; Yu, J.; Du, C.

    2014-12-01

    Evapotranspiration (ET) including evaporation from soil surfaces and transpiration through plants' stomata exerts dominant controls on shallow groundwater dynamics under hyper-arid climates. Our analyses of diurnal and seasonal groundwater dynamics at desert sites in northwestern China for the period 2010-2014 showed that different patterns of groundwater dynamics in a Gobi-desert and riparian zones are highly related to ET processes. To quantify ET in the hyper-arid climates, we developed diagnostic indicators of the groundwater-ET relationship and a methodology based on seasonal groundwater level fluctuation approach. Under similar climates and depth to the water table (2-2.5 m), ET in the riparian zones as a result of direct root water uptake (RWU) through riparian shrubs (0.63-0.73 mm/d at the Tamarix ramosissima site and 1.89-2.33 mm/d at the Populus euphratica site) is much greater than that in a Gobi-desert site (0.12-0.27 mm/d). Numerical simulations using a one-dimensional land surface model with a RWU model that explicitly describes root-groundwater interactions indicate that direct RWU at the riparian sites is primarily dependent on the root dynamics that interacts with groundwater dynamics.

  18. Implications of the results of colonization experiments for designing riparian restoration projects adjacent to agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many headwater streams and their riparian habitats in the Midwestern United States have been modified for agricultural drainage. Agricultural drainage often results in reductions of physical habitat diversity, shifts from woody to herbaceous riparian vegetation, and the loss of riparian habitat. T...

  19. Groundwater flow path dynamics and nitrogen transport potential in the riparian zone of an agricultural headwater catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream riparian zones are often thought of as areas that provide natural remediation for groundwater contaminants, especially agricultural nitrogen (N). While denitrification and vegetative uptake tend to be efficient N removal processes in slow moving shallow groundwater, these mechanisms decrease ...

  20. Validating modelled variable surface saturation in the riparian zone with thermal infrared images

    NASA Astrophysics Data System (ADS)

    Glaser, Barbara; Klaus, Julian; Frei, Sven; Frentress, Jay; Pfister, Laurent; Hopp, Luisa

    2015-04-01

    Variable contributing areas and hydrological connectivity have become prominent new concepts for hydrologic process understanding in recent years. The dynamic connectivity within the hillslope-riparian-stream (HRS) system is known to have a first order control on discharge generation and especially the riparian zone functions as runoff buffering or producing zone. However, despite their importance, the highly dynamic processes of contraction and extension of saturation within the riparian zone and its impact on runoff generation still remain not fully understood. In this study, we analysed the potential of a distributed, fully coupled and physically based model (HydroGeoSphere) to represent the spatial and temporal water flux dynamics of a forested headwater HRS system (6 ha) in western Luxembourg. The model was set up and parameterised under consideration of experimentally-derived knowledge of catchment structure and was run for a period of four years (October 2010 to August 2014). For model evaluation, we especially focused on the temporally varying spatial patterns of surface saturation. We used ground-based thermal infrared (TIR) imagery to map surface saturation with a high spatial and temporal resolution and collected 20 panoramic snapshots of the riparian zone (ca. 10 by 20 m) under different hydrologic conditions. These TIR panoramas were used in addition to several classical discharge and soil moisture time series for a spatially-distributed model validation. In a manual calibration process we optimised model parameters (e.g. porosity, saturated hydraulic conductivity, evaporation depth) to achieve a better agreement between observed and modelled discharges and soil moistures. The subsequent validation of surface saturation patterns by a visual comparison of processed TIR panoramas and corresponding model output panoramas revealed an overall good accordance for all but one region that was always too dry in the model. However, quantitative comparisons of

  1. Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

    PubMed

    Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

    2015-05-01

    In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

  2. Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

    PubMed

    Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

    2015-05-01

    In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

  3. Effects of inundation frequency on microbial N cycling in the riparian zones of pristine watersheds

    NASA Astrophysics Data System (ADS)

    Malone, E. T.; Bartlett, R.; Pinay, G.; Milner, A. M.

    2012-12-01

    Although the N cycle has been intensively studied new reaction pathways are being discovered. Perturbation by anthropogenic N inputs changes the type of loading and cycling processes in soil systems. Few pristine environments remain in which to study natural controls on the development of N cycling to increase our understanding of the natural development of such mechanisms and with which to compare the effects of anthropogenic inputs. This study took place in Glacier Bay National Park and Preserve, in southeast Alaska (GBNP).Where rapid de-glaciation over the last 250 years has created watersheds of different ages free from anthropogenic N inputs, permitting a unique opportunity to study the evolution of microbial N cycling in pristine soil systems. Soil N cycling was assessed within six study streams selected across a chronosequence of 200 years of primary succession. A combination of field and laboratory methods were used to assess the soil inorganic N status of each study site and assess the net, gross and potential microbial processing of N (ammonification, nitrification and denitrification) present within the soil. Soil samples were collected from the riparian zones of the six river catchments with varying inundation frequencies; namely 1) frequently inundated bare sediment adjacent to the river channel; 2) vegetated floodplain areas further from the channel inundated during high flow events; 3) non flooded. This approach allowed a cross stream comparison of microbial N processing for a range of soil ages, and under differing inundation regimes. Evolution of soil N processing could then be examined, in relation to successional changes in the wider river catchment. One of the key findings was that one of the primary influences on nitrogen cycling processes in the study areas was vegetation cover, as a function of site resilience and distance from stream channel. With distance from a stream channel, a site becomes less dynamic, thereby allowing for the

  4. Riparian zone hydrology and biogeochemistry as a function of stream evolution stage in glaciated landscapes of the US Northeast

    NASA Astrophysics Data System (ADS)

    Rook, S. P.; Vidon, P.; Walter, M. T.

    2011-12-01

    The management of riparian buffer strips is often regarded as one of the most economical and sustainable methods of managing non-point source pollution and water quality. However, current riparian management often follows a 'one size fits all' design, which fails to recognize the complexity of the many biogeochemical processes that regulate pollutant transformation and retention in these systems. This study addresses two critical gaps in knowledge: (1) How carbon, nitrogen, phosphorous, and iron cycles interact with one another (rather than individually). (2) How stream channel geometry and evolution regulate these nutrient cycles and greenhouse gas (GHG) dynamics in the near stream zone. This project specifically explores the hydrological and biogeochemical functioning of riparian zones across a gradient of stream meander evolution stages, with the primary goal of understanding and predicting potential interactions between nutrient dynamics in these systems. Key research questions include: (1) How does stream meander curvature affect riparian zone hydrology? (2) How does stream meander curvature influence riparian zone biogeochemistry? (3) What relationships exist among N, P, Fe, and GHG dynamics? We instrumented three riparian sites near Ithaca, NY, with a dense network of wells, piezometers, and static chambers. These sites represent three riparian zones along three evolution stages of stream meanders: an inner meander, a straight stream section, and an outer bend of the stream with an oxbow lake formation. In spring through fall 2011, water samples and gas samples were collected at a tri-weekly bases at each of the three sites. Water samples were analyzed for oxidation-reduction potential, dissolved oxygen, temperature, FeII/FeIII, nutrients (NO3-, NH4+, PO43-) and dissolved organic carbon (DOC). GHG fluxes at the soil-atmosphere interface were measured for N2O, CO2, and CH4 gases. We predict that stream curvature will significantly affect groundwater flow

  5. Hydrological responses in a pre-alpine head watershed: the role of hillslopes and riparian zones

    NASA Astrophysics Data System (ADS)

    von Freyberg, Jana; Radny, Dirk; Schirmer, Mario

    2014-05-01

    Mountainous watersheds are characterized by generally high precipitation inputs and very heterogeneous landscape properties, which make them very dynamic hydrologic systems that play an important role in the water cycle. Their groundwater systems sustain downstream baseflow in larger catchments in many parts of the world, particularly in the densely populated lowlands of Switzerland. Hillslope aquifers are often categorized as one of the dominant groundwater resources in mountainous watersheds. These aquifers may also act as source areas for pollutants in rivers due to intensive agricultural land use. In our study we seek to improve the understanding of the groundwater flow processes and runoff generation mechanisms in high altitude watersheds, under explicit consideration of the joint behaviors of climate and groundwater. The role of the hillslope groundwater contribution to catchment outflow and streamflow composition was investigated in the pre-alpine Rietholzbach catchment (~1 sq km) in northeast Switzerland. The field site, equipped with an extensive hydrometric setup, facilitates the monitoring of annual, inter-seasonal and short-term dynamics of water flow and composition, as well as its links to associated parameters describing atmospheric, surface and subsurface properties. In this study, we focused on the effects of antecedent moisture, rainfall characteristics and landscape properties on groundwater and river responses in order to develop a conceptual model of runoff generation. Our observations indicate generally low hydraulic conductivities and average groundwater travel times of several months in the hillslope aquifers resulting from high clay-contents of the unconsolidated glacial Moraine deposits. Event analysis revealed that only a small portion of the total watershed area generates event discharge and we have identified the saturated valley bottom (riparian zones) and lower hillslopes as the two dominant hydrological landscape units. Runoff

  6. Occupancy patterns of mammals and lentic amphibians in the Elwha River riparian zone before dam removal

    USGS Publications Warehouse

    Jenkins, Kurt J.; Chelgren, Nathan; Sager-Fradkin, K.A.; Happe, P.J.; Adams, Michael J.

    2015-01-01

    The downstream transport of sediments and organics and upstream migration of anadromous fishes are key ecological processes in unregulated riverine ecosystems of the North Pacific coast, but their influence on wildlife habitats and populations is poorly documented. Removal of two large hydroelectric dams in Washington’s Elwha Valley provides an unprecedented opportunity to study long-term responses of wildlife populations to dam removal and restoration of these key ecological processes. We compared pre-dam removal patterns in the relative abundance and occupancy of mesocarnivores, small mammals and lentic amphibians of the Elwha River riparian zone above, between and below the dams. Occupancy of riparian habitats by three mesocarnivore species diminished upriver but did not appear to be closely linked with the absence of salmon in the upper river. Although the importance of salmon in the lower river cannot be discounted, other gradients in food resources also likely contributed to observed distribution patterns of mesocarnivores. Abundance and occupancy patterns within congeneric pairs of new world mice (Peromyscus spp.) and shrews (Sorex spp.) indicated that closely related species were negatively associated with each other and responded to habitat gradients in the riparian zone. The availability of lentic habitats of amphibians was highly variable, and occupancy was low as a result of rapidly changing flows during the larval development period. We speculate that long-term changes in habitat conditions and salmon availability following dam removal will elicit long-term changes in distribution of mesocarnivores, small mammals and amphibians. Long-term monitoring will enhance understanding of the role of fish and restored ecosystem processes on wildlife communities along salmon-bearing rivers in the region.

  7. An Analytical Solution of Groundwater Evapotranspiration in Arid Riparian Zone: A Case Study for the Tarim River in China

    NASA Astrophysics Data System (ADS)

    Cong, Z.; Dang, Q.; Wang, L.

    2012-12-01

    Groundwater evapotranspiration (ET) constitutes a major component of the water balance in arid riparian zone. Most of groundwater ET studies depend on numerical models but it is not easy to discuss the controling factors of groundwater ET in riparian zone. A two-dimension conceptal framework was set up to understand the groundwater ET in arid riparian zone. We deduced an analytical solution and its simplification of riparian ET based on a negative exponential relation between groundwater ET and groundwater depth. The groundwaer ET is controlled by soil type (soil hydraulic condontivity and parameter in the negative exponential relation), aquifer thickness, potential ET and river water table. Three soil types (sand, sandy loam and loam) with different soil texture were selected to discuss the riparian ET and it was found that the riaprian ET is similar for different soil type. The framework and analytical solution are applied in Tarim River in China where a river restoration project had been put into practice. The discussions are helpful to design water supply pattern of river restoration.

  8. [Relationship between groundwater quality index of physics and chemistry in riparian zone and water quality in river].

    PubMed

    Xu, Hua-Shan; Zhao, Tong-Qian; Meng, Hong-Qi; Xu, Zong-Xue; Ma, Chao-Hong

    2011-03-01

    Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that, affected by the river and pond water, the highest point of groundwater temperature is near the pond in spring, and near the river in winter; and regulation for water and sediment at the Xiaolangdi Reservoir also affects groundwater temperature in riparian zone, which reaches its maximum at 100 m far from the river bank. There exists a strong zone of nitrification area at 50 m from the river bank, and in this area, the groundwater pH value is lower by 0.2 to 0.4 unit than that of the other regions, with great annual varieties. The turbidity of groundwater is affected by irrigation, which is more obvious than other indicators of groundwater. The turbidity of groundwater and river water increase rapidly during the early phase of flood retreat, and slope stability of river bank is the initial impact of the soil erosion of river bank. Conductivity, chloride and sulfate data show that the range of 50-200 m in riparian wetland is a very important salt accumulation zone, and the width of salt accumulation zone changes with seasons, and this area is also a very important zone of sulfur reduction. The quality of groundwater at 200 m from the river bank is also significantly affected by floods. Physical and chemical indicators of water change strongly in this area. The result indicates that

  9. [Relationship between groundwater quality index of physics and chemistry in riparian zone and water quality in river].

    PubMed

    Xu, Hua-Shan; Zhao, Tong-Qian; Meng, Hong-Qi; Xu, Zong-Xue; Ma, Chao-Hong

    2011-03-01

    Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that, affected by the river and pond water, the highest point of groundwater temperature is near the pond in spring, and near the river in winter; and regulation for water and sediment at the Xiaolangdi Reservoir also affects groundwater temperature in riparian zone, which reaches its maximum at 100 m far from the river bank. There exists a strong zone of nitrification area at 50 m from the river bank, and in this area, the groundwater pH value is lower by 0.2 to 0.4 unit than that of the other regions, with great annual varieties. The turbidity of groundwater is affected by irrigation, which is more obvious than other indicators of groundwater. The turbidity of groundwater and river water increase rapidly during the early phase of flood retreat, and slope stability of river bank is the initial impact of the soil erosion of river bank. Conductivity, chloride and sulfate data show that the range of 50-200 m in riparian wetland is a very important salt accumulation zone, and the width of salt accumulation zone changes with seasons, and this area is also a very important zone of sulfur reduction. The quality of groundwater at 200 m from the river bank is also significantly affected by floods. Physical and chemical indicators of water change strongly in this area. The result indicates that

  10. Riparian zones attenuate nitrogen loss following bark beetle-induced lodgepole pine mortality

    NASA Astrophysics Data System (ADS)

    Biederman, Joel A.; Meixner, Thomas; Harpold, Adrian A.; Reed, David E.; Gutmann, Ethan D.; Gaun, Janelle A.; Brooks, Paul D.

    2016-03-01

    A North American bark beetle infestation has killed billions of trees, increasing soil nitrogen and raising concern for N loss impacts on downstream ecosystems and water resources. There is surprisingly little evidence of stream N response in large basins, which may result from surviving vegetation uptake, gaseous loss, or dilution by streamflow from unimpacted stands. Observations are lacking along hydrologic flow paths connecting soils with streams, challenging our ability to determine where and how attenuation occurs. Here we quantified biogeochemical concentrations and fluxes at a lodgepole pine-dominated site where bark beetle infestation killed 50-60% of trees. We used nested observations along hydrologic flow paths connecting hillslope soils to streams of up to third order. We found soil water NO3 concentrations increased 100-fold compared to prior research at this and nearby southeast Wyoming sites. Nitrogen was lost below the major rooting zone to hillslope groundwater, where dissolved organic nitrogen (DON) increased by 3-10 times (mean 1.65 mg L-1) and NO3-N increased more than 100-fold (3.68 mg L-1) compared to preinfestation concentrations. Most of this N was removed as hillslope groundwater drained through riparian soils, and NO3 remained low in streams. DON entering the stream decreased 50% within 5 km downstream, to concentrations typical of unimpacted subalpine streams (~0.3 mg L-1). Although beetle outbreak caused hillslope N losses similar to other disturbances, up to 5.5 kg ha-1y-1, riparian and in-stream removal limited headwater catchment export to <1 kg ha-1y-1. These observations suggest riparian removal was the dominant mechanism preventing hillslope N loss from impacting streams.

  11. Hot spots and hot moments of carbon and nitrogen dynamics in a semiarid riparian zone

    NASA Astrophysics Data System (ADS)

    Harms, Tamara K.; Grimm, Nancy B.

    2008-03-01

    Riparian ecosystems are characterized by spatial and temporal heterogeneity in physical and biological attributes, with consequences for nutrient cycling. We investigated the responses of carbon (C) and nitrogen (N) cycling processes to the hydrogeomorphic template in the riparian zone of the San Pedro River, Arizona, a large (catchment area ˜11,500 km2), free-flowing, semiarid river. Over an annual period we documented spatial and temporal patterns in soil, shallow groundwater, and stream nutrient chemistry as well as rates of N-transforming processes in soils of the surface (0-17 cm) and region of seasonal saturation (RoSS). A hot moment of N retention and removal was indicated by elevated rates of microbial processes during the summer monsoon season. At the same time, elevated C was observed in soil microbial biomass for both surface soils and soils in the RoSS. Analyses of C-use profiles for soil microbes, coupled with trends in stream and shallow-groundwater chemistry, further suggest that this hot moment of N removal was fueled by newly available, labile organic material. In a spatial context, patchiness in soil resources, microbial biomass, and potential denitrification were best explained by variation in microtopography; low-elevation landscape positions were hot spots of resource availability and microbial activity. Vertical heterogeneity also corresponded with variation in the factors influencing N transformation rates. Organic matter was more frequently a significant factor explaining N transformation rates in RoSS soils whereas soil water content was more often important in surface soils. Together, these patterns suggest that understanding the points on the hydrogeomorphic template, both in space and in time, that bring together water and labile organic matter will lead to greater predictive capability regarding C and N cycling in semiarid river-riparian corridors.

  12. Hydrological characterization of a riparian vegetation zone using high resolution multi-spectral airborne imagery

    NASA Astrophysics Data System (ADS)

    Akasheh, Osama Z.

    The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, which affect the river aquatic system. The need to study the river hydrological processes and their relation with its health is important to preserve the river ecosystem. To be able to do that a detailed vegetation map was produced using a Utah State University airborne remote sensing system for 286 km of river reach. Also a groundwater model was built in ArcGIS environment which has the ability to estimate soil water potential in the root zone and above the modeled water table. The Modified Penman-Monteith empirical equation was used in the ArcGIS environment to estimate riparian vegetation ET, taking advantage of the detailed vegetation map and spatial soil water potential layers. Vegetation water use per linear river reach was estimated to help decision makers to better manage and release the amount of water that keeps a sound river ecosystem and to support agricultural activities.

  13. From Midges to Spiders: Mercury Biotransport in Riparian Zones Near the Buffalo River Area of Concern (AOC), USA.

    PubMed

    Pennuto, C M; Smith, M

    2015-12-01

    Riparian communities can receive environmental contaminants from adjacent aquatic 'donor' habitats. We investigated mercury biotransport from aquatic to terrestrial habitats via aquatic insect emergence and uptake by riparian spiders at sites within and upstream of the Buffalo River Area of Concern (AOC), a site with known sediment Hg contamination. Mercury concentration in emerging midges was roughly 10× less than contaminated sediment levels with the AOC, but biomagnification factors from midges to spiders ranged from 2.0 to 2.65 between sites. There was a significantly negative body mass:total mercury relationship in spiders (p < 0.001), indicating that mercury depuration is rapid or tissue dilution occurs in these riparian predators. Spiders contained significantly more mercury than their midge prey and spiders upstream of the AOC had higher mercury concentrations than spiders from within the AOC. Collectively, these data indicate that riparian spiders can be good mercury sentinels in urban environments, and that riparian communities upstream from the AOC may be at greater risk to mercury than has been previously considered. PMID:26387024

  14. From Midges to Spiders: Mercury Biotransport in Riparian Zones Near the Buffalo River Area of Concern (AOC), USA.

    PubMed

    Pennuto, C M; Smith, M

    2015-12-01

    Riparian communities can receive environmental contaminants from adjacent aquatic 'donor' habitats. We investigated mercury biotransport from aquatic to terrestrial habitats via aquatic insect emergence and uptake by riparian spiders at sites within and upstream of the Buffalo River Area of Concern (AOC), a site with known sediment Hg contamination. Mercury concentration in emerging midges was roughly 10× less than contaminated sediment levels with the AOC, but biomagnification factors from midges to spiders ranged from 2.0 to 2.65 between sites. There was a significantly negative body mass:total mercury relationship in spiders (p < 0.001), indicating that mercury depuration is rapid or tissue dilution occurs in these riparian predators. Spiders contained significantly more mercury than their midge prey and spiders upstream of the AOC had higher mercury concentrations than spiders from within the AOC. Collectively, these data indicate that riparian spiders can be good mercury sentinels in urban environments, and that riparian communities upstream from the AOC may be at greater risk to mercury than has been previously considered.

  15. RIPARIAN BUFFER WIDTH, VEGETATIVE COVER, AND NITROGEN REMOVAL EFFECTIVENESS: A REVIEW OF CURRENT SCIENCE AND REGULATIONS

    EPA Science Inventory

    Riparian zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Buffer width may be positively related to nitrogen removal efficiency by influencing nitrogen retention throug...

  16. RIPARIAN BUFFER WIDTH, VEGETATIVE COVER, AND NITROGEN REMOVAL EFFECTIVENESS: A REVIEW OF CURRENT SCIENCE AND REGULATIONS

    EPA Science Inventory

    Riparian zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Buffer width may be related to nitrogen removal efficiency by influencing nitrogen retention through plant seq...

  17. Distribution of inorganic phosphorus in profiles and particle-size fractions across an established riparian buffer and adjacent cropped area at the Dian lake

    NASA Astrophysics Data System (ADS)

    Zhang, G. S.; Li, J. C.

    2015-11-01

    Riparian buffer can trap sediment and nutrients sourced from upper cropland and minimizing eutrophication risk of water quality. This study aimed to investigate the distributions of soil inorganic phosphorus (Pi) forms among profile and particle-size fractions in an established riparian buffer and adjacent cropped area at the Dian lake, Southwestern China. The Ca-bound fraction (62 %) was the major proportion of the Pi in the riparian soils. Buffer rehabilitation from cropped area had a limited impact on total phosphorus (TP) concentrations after 3 years, but has contributed to a change in Pi forms. At 0-20 cm soil layer, levels of the Olsen-P, nonoccluded, Ca-bound and total Pi were lower in the buffer than the cropped area; however, the Pi distribution between the cropped area and the buffer did not differ significantly as depth increased. The clay fraction corresponded to 57 % of TP and seemed to be both a sink for highly recalcitrant Pi and a source for labile Pi. The lower concentration of Pi forms in the silt and sand particle fraction in the surface soil was observed in the buffer area, which indicating that the Pi distribution in coarse particle fraction has sensitively responded to land-use changes.

  18. Distribution of inorganic phosphorus in profiles and particle fractions of Anthrosols across an established riparian buffer and adjacent cropped area at the Dian lake (China)

    NASA Astrophysics Data System (ADS)

    Zhang, Guo Sheng; Cha Li, Jian

    2016-02-01

    Riparian buffers can trap sediment and nutrients sourced from upper cropland, minimizing the eutrophication risk of water quality. This study aimed to investigate the distributions of soil inorganic phosphorus (Pi) forms among profile and particle-size fractions in an established riparian buffer and adjacent cropped area at the Dian lake, southwestern China. The Ca-bound fraction (62 %) was the major proportion of the Pi in the riparian soils. After 3 years' restoration, buffer rehabilitation from cropped area had a limited impact on total phosphorus (TP) concentrations, but has contributed to a change in Pi forms. In the 0-20 cm soil layer, levels of the Olsen-P, non-occluded, Ca-bound, and total Pi were lower in the buffer than the cropped area; however, the Pi distribution between the cropped area and the buffer did not differ significantly as depth increased. The clay fraction corresponded to 57 % of TP and seemed to be both a sink for highly recalcitrant Pi and a source for labile Pi. The lower concentration of Pi forms in the silt and sand particle fraction in the surface soil was observed in the buffer area, which indicated that the Pi distribution in coarse particle fraction had sensitively responded to land use changes.

  19. Seasonal change detection of riparian zones with remote sensing images and genetic programming in a semi-arid watershed.

    PubMed

    Makkeasorn, Ammarin; Chang, Ni-Bin; Li, Jiahong

    2009-02-01

    Riparian zones are deemed significant due to their interception capability of non-point source impacts and the maintenance of ecosystem integrity region wide. To improve classification and change detection of riparian buffers, this paper developed an evolutionary computational, supervised classification method--the RIparian Classification Algorithm (RICAL)--to conduct the seasonal change detection of riparian zones in a vast semi-arid watershed, South Texas. RICAL uniquely demonstrates an integrative effort to incorporate both vegetation indices and soil moisture images derived from LANDSAT 5 TM and RADARSAT-1 satellite images, respectively. First, an estimation of soil moisture based on RADARSAT-1 Synthetic Aperture Radar (SAR) images was conducted via the first-stage genetic programming (GP) practice. Second, for the statistical analyses and image classification, eight vegetation indices were prepared based on reflectance factors that were calculated as the response of the instrument on LANDSAT. These spectral vegetation indices were then independently used for discriminate analysis along with soil moisture images to classify the riparian zones via the second-stage GP practice. The practical implementation was assessed by a case study in the Choke Canyon Reservoir Watershed (CCRW), South Texas, which is mostly agricultural and range land in a semi-arid coastal environment. To enhance the application potential, a combination of Iterative Self-Organizing Data Analysis Techniques (ISODATA) and maximum likelihood supervised classification was also performed for spectral discrimination and classification of riparian varieties comparatively. Research findings show that the RICAL algorithm may yield around 90% accuracy based on the unseen ground data. But using different vegetation indices would not significantly improve the final quality of the spectral discrimination and classification. Such practices may lead to the formulation of more effective management strategies

  20. Occurrence and controls on transport and transformation of nitrogen in riparian zones of Dongting Lake, China.

    PubMed

    Zhao, Shan; Zhou, Nianqing; Liu, Xiaoqun

    2016-04-01

    Dongting Lake is the second largest freshwater lake in China. It is suffering from significant eutrophication as a result of excessive nutrients inputs, among which nitrogen (N) is becoming a major contributor. The objective of this study is to document the occurrence and controls on N transport and transformation in riparian zones of Dongting Lake wetland. Field experiments were conducted in the cultivated Li River (LR) and uncultivated Yuan River (YR) regions of the wetlands from June to November, 2014. Groundwater depth, redox potential (Eh), pH, and temperature were measured in situ. Groundwater and surface water samples were collected to determine concentrations of nitrate nitrogen (NO3 (-)-N), nitrite nitrogen (NO2 (-)-N), and ammonia nitrogen (NH4 (+)-N). The results showed that NH4 (+)-N was the dominant N pollutant with maximum average value of 2.7760 mg L(-1). All the groundwater samples were rated to Class V based on NH4 (+)-N content according to the groundwater quality standard, indicating the load of N in riparian zones had exceeded their capacity for assimilation and purification. Internal controls (including Eh and pH, temperature, and groundwater depth) and external controls (including surface water, land use, and rainfall) were analyzed in detail. The results suggested that Eh and pH were more significant in controlling N transport and transformation than temperature and groundwater depth; external controls influenced N fates through imposing an effect on internal controls. This study will provide important insights and a scientific basis for N pollution treatment and better protection of the Dongting Lake wetlands. PMID:26635216

  1. Short-term spatial and temporal variability in greenhouse gas fluxes in riparian zones.

    PubMed

    Vidon, P; Marchese, S; Welsh, M; McMillan, S

    2015-08-01

    Recent research indicates that riparian zones have the potential to contribute significant amounts of greenhouse gases (GHG: N2O, CO2, CH4) to the atmosphere. Yet, the short-term spatial and temporal variability in GHG emission in these systems is poorly understood. Using two transects of three static chambers at two North Carolina agricultural riparian zones (one restored, one unrestored), we show that estimates of the average GHG flux at the site scale can vary by one order of magnitude depending on whether the mean or the median is used as a measure of central tendency. Because the median tends to mute the effect of outlier points (hot spots and hot moments), we propose that both must be reported or that other more advanced spatial averaging techniques (e.g., kriging, area-weighted average) should be used to estimate GHG fluxes at the site scale. Results also indicate that short-term temporal variability in GHG fluxes (a few days) under seemingly constant temperature and hydrological conditions can be as large as spatial variability at the site scale, suggesting that the scientific community should rethink sampling protocols for GHG at the soil-atmosphere interface to include repeated measures over short periods of time at select chambers to estimate GHG emissions in the field. Although recent advances in technology provide tools to address these challenges, their cost is often too high for widespread implementation. Until technology improves, sampling design strategies will need to be carefully considered to balance cost, time, and spatial and temporal representativeness of measurements.

  2. Occurrence and controls on transport and transformation of nitrogen in riparian zones of Dongting Lake, China.

    PubMed

    Zhao, Shan; Zhou, Nianqing; Liu, Xiaoqun

    2016-04-01

    Dongting Lake is the second largest freshwater lake in China. It is suffering from significant eutrophication as a result of excessive nutrients inputs, among which nitrogen (N) is becoming a major contributor. The objective of this study is to document the occurrence and controls on N transport and transformation in riparian zones of Dongting Lake wetland. Field experiments were conducted in the cultivated Li River (LR) and uncultivated Yuan River (YR) regions of the wetlands from June to November, 2014. Groundwater depth, redox potential (Eh), pH, and temperature were measured in situ. Groundwater and surface water samples were collected to determine concentrations of nitrate nitrogen (NO3 (-)-N), nitrite nitrogen (NO2 (-)-N), and ammonia nitrogen (NH4 (+)-N). The results showed that NH4 (+)-N was the dominant N pollutant with maximum average value of 2.7760 mg L(-1). All the groundwater samples were rated to Class V based on NH4 (+)-N content according to the groundwater quality standard, indicating the load of N in riparian zones had exceeded their capacity for assimilation and purification. Internal controls (including Eh and pH, temperature, and groundwater depth) and external controls (including surface water, land use, and rainfall) were analyzed in detail. The results suggested that Eh and pH were more significant in controlling N transport and transformation than temperature and groundwater depth; external controls influenced N fates through imposing an effect on internal controls. This study will provide important insights and a scientific basis for N pollution treatment and better protection of the Dongting Lake wetlands.

  3. Evaluation the effect of riparian zones on nitrate removal at the river basin scale using the SWAT model

    NASA Astrophysics Data System (ADS)

    Hoang, Linh; van Griensven, Ann; Mynett, Arthur

    2014-05-01

    In this paper, a modified version of the The Soil and Water Assessment Tool (SWAT), referred to as SWAT_LS, which takes into account interactions between landscape units, was applied in the Odense river basin, an agriculture-dominated and a densely tile-drained river basin. The objectives of this paper are to (i) evaluate the effect of the SWAT modifications in flow and nitrogen simulations by comparing with the original SWAT model taking into account parameter uncertainty, and (ii) estimate the effect of riparian zone in nitrate removal in the Odense river basin. The results showed that compared to the original SWAT2005, SWAT_LS gave improvements in the simulation of flow and nitrate fluxes evaluating based on the Nash-Sutcliffe coefficients. Taking into account parameter uncertainty by running Monte-Carlo simulations, SWAT_LS had a considerably higher number of parameter sets that resulted in satisfactory performances (behavioral models) in both daily and monthly time steps. It implies that SWAT_LS performed better than SWAT2005 by giving higher probability to get a satisfactory representation of the modelled river basin although uncertainty bounds are compatible between the two models. Considering parameter uncertainty, it was also shown that presently, riparian zones in the Odense river basin is only able to remove 4 ~ 17% nitrate fluxes by denitrification because a majority of riparian zones are artificially drained and dominated by tile drainage. However, if all riparian zones in the area are not drained and is able to fully perform their retention function, the effectiveness of riparian zones for nitrate removal will increase dramatically up to 25 ~ 85%.

  4. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a) Atlantic Ocean in vicinity of No Mans Land—(1) The area. The waters surrounding No Mans Land within an...

  5. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a) Atlantic Ocean in vicinity of No Mans Land—(1) The area. The waters surrounding No Mans Land within an...

  6. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a) Atlantic Ocean in vicinity of No Mans Land—(1) The area. The waters surrounding No Mans Land within an...

  7. Boreal forest riparian zones regulate stream sulfate and dissolved organic carbon.

    PubMed

    Ledesma, José L J; Futter, Martyn N; Laudon, Hjalmar; Evans, Christopher D; Köhler, Stephan J

    2016-08-01

    In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeochemical processes occurring in the riparian zone (RZ). However, RZs are spatially heterogeneous and information about solute chemistry is typically limited. This is problematic when making inferences about stream chemistry. Hypothetically, the strength of links between riparian and stream chemistry is time-scale dependent. Using a ten-year (2003-2012) dataset from a northern Swedish catchment, we evaluated the suitability of RZ data to infer stream dynamics at different time scales. We focus on the role of the RZ versus upslope soils in controlling sulfate (SO4(2)(-)) and dissolved organic carbon (DOC). A priori, declines in acid deposition and redox-mediated SO4(2)(-) pulses control sulfur (S) fluxes and pool dynamics, which in turn affect dissolved organic carbon (DOC). We found that the catchment is currently a net source of S, presumably due to release of the S pool accumulated during the acidification period. In both, RZ and stream, SO4(2-) concentrations are declining over time, whereas DOC is increasing. No temporal trends in SO4(2-) and DOC were observed in upslope mineral soils. SO4(2-) explained the variation of DOC in stream and RZ, but not in upslope mineral soil. Moreover, as SO4(2-) decreased with time, temporal variability of DOC increased. These observations indicate that: (1) SO4(2-) is still an important driver of DOC trends in boreal catchments and (2) RZ processes control stream SO4(2-) and subsequently DOC independently of upslope soils. These phenomena are likely occurring in many regions recovering from acidification. Because water flows through a heterogeneous mosaic of RZs before entering the stream, upscaling information from limited RZ data to the catchment level is problematic at short-time scales. However, for long-term trends and annual dynamics, the same data can provide reasonable representations of riparian processes and support

  8. Boreal forest riparian zones regulate stream sulfate and dissolved organic carbon.

    PubMed

    Ledesma, José L J; Futter, Martyn N; Laudon, Hjalmar; Evans, Christopher D; Köhler, Stephan J

    2016-08-01

    In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeochemical processes occurring in the riparian zone (RZ). However, RZs are spatially heterogeneous and information about solute chemistry is typically limited. This is problematic when making inferences about stream chemistry. Hypothetically, the strength of links between riparian and stream chemistry is time-scale dependent. Using a ten-year (2003-2012) dataset from a northern Swedish catchment, we evaluated the suitability of RZ data to infer stream dynamics at different time scales. We focus on the role of the RZ versus upslope soils in controlling sulfate (SO4(2)(-)) and dissolved organic carbon (DOC). A priori, declines in acid deposition and redox-mediated SO4(2)(-) pulses control sulfur (S) fluxes and pool dynamics, which in turn affect dissolved organic carbon (DOC). We found that the catchment is currently a net source of S, presumably due to release of the S pool accumulated during the acidification period. In both, RZ and stream, SO4(2-) concentrations are declining over time, whereas DOC is increasing. No temporal trends in SO4(2-) and DOC were observed in upslope mineral soils. SO4(2-) explained the variation of DOC in stream and RZ, but not in upslope mineral soil. Moreover, as SO4(2-) decreased with time, temporal variability of DOC increased. These observations indicate that: (1) SO4(2-) is still an important driver of DOC trends in boreal catchments and (2) RZ processes control stream SO4(2-) and subsequently DOC independently of upslope soils. These phenomena are likely occurring in many regions recovering from acidification. Because water flows through a heterogeneous mosaic of RZs before entering the stream, upscaling information from limited RZ data to the catchment level is problematic at short-time scales. However, for long-term trends and annual dynamics, the same data can provide reasonable representations of riparian processes and support

  9. Mercury contamination in the riparian zones along the East Fork Poplar Creek at Oak Ridge.

    PubMed

    Pant, P; Allen, M; Tansel, B

    2011-03-01

    Oak Ridge (Tennessee, USA) has a history of mercury (Hg) contamination in its aquatic and soil environment associated with past nuclear-weapons production activities at its Department of Energy (DOE) sites. Three different riparian zones along the Lower East Fork Poplar Creek were investigated in order to study Hg distribution and transformation in surface soils. The surface soil samples collected from these areas showed higher total Hg on an average (129.08 mg/kg) and higher total organic carbon (5.50%) in the upstream soils compared to the other two downstream locations that contained only 31.78 and 19.98 mg/kg total Hg and 2.88% and 1.65% of TOC on average, respectively. Further, methyl Hg concentrations were also comparatively higher in case of the upstream soils (30.10 μg/kg) than that of the downstream sites (5.69 and 4.05 μg/kg). The study showed a plume-like dispersion of Hg in the terrestrial environment along the creek, with decreasing Hg concentrations with distance from the Hg source zone. Also, the transformation of Hg in the soils was found to have been influenced by the soil TOC contents. PMID:20965567

  10. 75 FR 65278 - Pamlico Sound and Adjacent Waters, NC; Danger Zones for Marine Corps Operations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... of Engineers, Department of the Army 33 CFR Part 334 Pamlico Sound and Adjacent Waters, NC; Danger... its regulations to establish one new danger zone in Pamlico Sound near Marine Corps Air Station Cherry Point, North Carolina. Establishment of this danger zone will enable the Marine Corps to control...

  11. Coupled biogeochemical cycles in riparian zones with contrasting hydrogeomorphic characteristics in the US Midwest

    NASA Astrophysics Data System (ADS)

    Liu, X.

    2012-12-01

    In this study we aims to understand what drives the fate and transport of multiple contaminants sensitive to soil redox condition across hydrogeomorphic (HGM) gradient and evaluate overall biogeochemical functions of riparian zones regarding those contaminants. We conducted monthly field work for 19 consecutive months from November 2009 to May 2011 at three study sites representative for main HGM types at the US Midwest. We collected the parameters from different sources which include field parameters, such as topography, water table depth, oxidation reduction potential (ORP) and dissolved oxygen (DO), and groundwater chemistry, such as NH4+, NO3-, PO43-, SO42-, CI- , and Hg and MeHg. Our results demonstrated that seasonal water table fluctuations and groundwater flows characteristics at three sites are strongly affected by their HGM setting. Specifically, the convergence of quick rise of water table, high ORP and sharp decrease in concentrations of NO3- and SO42 from field edge to stream edge (60-90% at LWD and 90% at WR) in spring after snowmelt and early May, which could be explained by that snow melt and early summer rainfall are major drivers of fluctuations of water table, variations of ORP and transport and transformation of contaminants. Riparian zones removed NO3- and SO42- during high water table but released Mercury in summer at both LWD and WR, and sulfate reduction, ammonia production and MeHg production all occurred when ORP and water tables were low in summer. These results might reflect the strong ORP control on these processes at landscape scale. These findings supported our hypothesis. Other findings however contrast to our hypothesis. For instances, unusual high concentrations of nitrate and Hg at WR suggest that the transport and fate of multiple contaminants relate not only to HGM settings but geographic location and land use. Negligible variations of P concentration in groundwater indicate that the transformation of P is not sensitive to soil

  12. Evaluation of soil nitrogen emissions from riparian zones coupling simple process-oriented models with remote sensing data.

    PubMed

    Wang, Xuelei; Mannaerts, C M; Yang, Shengtian; Gao, Yunfei; Zheng, Donghai

    2010-07-15

    Riparian ecosystems have critical impacts on controlling the non-point source pollution and maintaining the health of aquatic ecosystems. In this study, a process oriented soil denitrification model was extended with algorithms from a simple nitrogen (N) cycle model and coupled to land surface remote sensing data to enhance its performance in spatial and temporal prediction of gaseous N emissions from soils in the riparian buffer zone surrounding the Guanting reservoir (China). The N emission model is based on chemical and physical relationships that govern the heat budget, soil moisture variations and nitrogen movement in soils. Besides soil water and heat processes, it includes nitrification, denitrification and ammonia (NH(3)) volatilization. SPOT-5 and Landsat-5 TM satellite data were used to derive spatial land surface information and the temporal variation in land cover parameters was also used to drive the model. A laboratory-scale anaerobic incubation experiment was used to estimate the soil denitrification model parameters for the different soil types. An in situ field-scale experiment was conducted to calibrate and validate the soil temperature, moisture and nitrogen sub-models. An indirect method was used to verify simulated N emissions, resulting in a coefficient of determination of R(2)=0.83 between simulated and observed values. Then the model was applied to the whole riparian buffer zone catchment, using the spatial resolution (10m) of the SPOT-5 image. Model sensitivity analysis showed that soil moisture was the most sensitive parameter for gaseous N emissions and soil denitrification was the main process affecting N losses to the atmosphere in the riparian area. From the aspect of land use management around the Guanting reservoir, the spatial structure and distribution of land cover and land use types in the riparian area should be adapted, to enhance faster ecological restoration of the wetland ecological system surrounding this strategically

  13. Mapping Variable Width Riparian Zones Utilizing Open Source Data: A Robust New Approach

    NASA Astrophysics Data System (ADS)

    Abood, S. A.; Maclean, A.

    2013-12-01

    Riparian buffers are dynamic, transitional ecosystems between aquatic and terrestrial ecosystems with well-defined vegetation and soil characteristics. Previous approaches to riparian buffer delineation have primarily utilized fixed width buffers. However, these methodologies only take the watercourse into consideration and ignore critical geomorphology, associated vegetation and soil characteristics. Utilizing spatial data readily available from government agencies and geospatial clearinghouses, such as DEMs and the National Hydrography Dataset, the Riparian Buffer Delineation Model (RBDM) offers advantages by harnessing the geospatial modeling capabilities of ArcMap GIS, incorporating a statistically valid sampling technique along the watercourse to accurately map the critical 50-year plain, and delineating a variable width riparian buffer. Options within the model allow incorporation of National Wetlands Inventory (NWI), Soil Survey Data (SSURGO), National Land Cover Data (NLCD) and/or Cropland Data Layer (CDL) to improve the accuracy and utility of the riparian buffers attributes. This approach recognizes the dynamic and transitional natures of riparian buffers by accounting for hydrologic, geomorphic and vegetation data as inputs into the delineation process. By allowing the incorporation of land cover data, decision makers acquire a useful tool to assist in managing riparian buffers. The model is formatted as an ArcMap toolbox for easy installation and does require a Spatial Analyst license. Variable width riparian buffer utilizing 50-year flood height and 10m DEM. RBDM Inputs

  14. The importance of the riparian zone and in-stream processes in nitrate attenuation in undisturbed and agricultural watersheds – a review of the scientific literature

    USGS Publications Warehouse

    Ranalli, Anthony J.; MacAlady, Donald L.

    2010-01-01

    We reviewed published studies from primarily glaciated regions in the United States, Canada, and Europe of the (1) transport of nitrate from terrestrial ecosystems to aquatic ecosystems, (2) attenuation of nitrate in the riparian zone of undisturbed and agricultural watersheds, (3) processes contributing to nitrate attenuation in riparian zones, (4) variation in the attenuation of nitrate in the riparian zone, and (5) importance of in-stream and hyporheic processes for nitrate attenuation in the stream channel. Our objectives were to synthesize the results of these studies and suggest methodologies to (1) monitor regional trends in nitrate concentration in undisturbed 1st order watersheds and (2) reduce nitrate loads in streams draining agricultural watersheds. Our review reveals that undisturbed headwater watersheds have been shown to be very retentive of nitrogen, but the importance of biogeochemical and hydrological riparian zone processes in retaining nitrogen in these watersheds has not been demonstrated as it has for agricultural watersheds. An understanding of the role of the riparian zone in nitrate attenuation in undisturbed watersheds is crucial because these watersheds are increasingly subject to stressors, such as changes in land use and climate, wildfire, and increases in atmospheric nitrogen deposition. In general, understanding processes controlling the concentration and flux of nitrate is critical to identifying and mapping the vulnerability of watersheds to water quality changes due to a variety of stressors. In undisturbed and agricultural watersheds we propose that understanding the importance of riparian zone processes in 2nd order and larger watersheds is critical. Research is needed that addresses the relative importance of how the following sources of nitrate along any given stream reach might change as watersheds increase in size and with flow: (1) inputs upstream from the reach, (2) tributary inflow, (3) water derived from the riparian zone

  15. Recharge processes in an alluvial aquifer riparian zone, Norman Landfill, Norman, Oklahoma, 1998-2000

    USGS Publications Warehouse

    Scholl, Martha; Christenson, Scott; Cozzarelli, Isabelle; Ferree, Dale; Jaeshke, Jeanne

    2005-01-01

    Analyses of stable isotope profiles (d2H and d18O) in the saturated zone, combined with water-table fluctuations, gave a comprehensive picture of recharge processes in an alluvial aquifer riparian zone. At the Norman Landfill U.S. Geological Survey Toxic Substances Hydrology research site in Norman, Oklahoma, recharge to the aquifer appears to drive biodegradation, contributing fresh supplies of electron acceptors for the attenuation of leachate compounds from the landfill. Quantifying recharge is a first step in studying this process in detail. Both chemical and physical methods were used to estimate recharge. Chemical methods included measuring the increase in recharge water in the saturated zone, as defined by isotopic signature, specific conductance or chloride measurements; and infiltration rate estimates using storm event isotopic signatures. Physical methods included measurement of water-table rise after individual rain events and on an approximately monthly time scale. Evapotranspiration rates were estimated using diurnal watertable fluctuations; outflux of water from the alluvial aquifer during the growing season had a large effect on net recharge at the site. Evaporation and methanogenesis gave unique isotopic signatures to different sources of water at the site, allowing the distinction of recharge using the offset of the isotopic signature from the local meteoric water line. The downward movement of water from large, isotopically depleted rain events in the saturated zone yielded recharge rate estimates (2.2 - 3.3 mm/day), and rates also were determined by observing changes in thickness of the layer of infiltrated recharge water at the top of the saturated zone (1.5 - 1.6 mm/day). Recharge measured over 2 years (1998-2000) in two locations at the site averaged 37 percent of rainfall, however, part of this water had only a short residence time in the aquifer. Isotopes showed recharge water entering the ground-water system in winter and spring, then being

  16. [Characteristics of Deposited Sediment and Assessment of Heavy Metals in Typical Tributaries Bay Riparian Zone of the Three Gorges Reservoir].

    PubMed

    Wang, Yong-yan; Wen, An-bang; Shi, Zhong-lin; Yan, Dong-chun; Zhu, Bo; Tang, Jia-liang

    2016-03-15

    In order to analyze the spatial variation characteristics of grain diameter, nutrient elements and heavy metal pollution with deposition sediment in tributaries bay of the Three Gorges Reservoir, we selected 9 typical tributaries bay, 54 deposited sediment samples were collected from the riparian zone for analyzing grain diameter distribution, capacity, organic matter, nutrient elements of TN, TP and K, heavy metal elements of Cr, Cu, Ni, Pb, and Zn. The results indicated that particle size distribution from Wujiang River in Fuling to the Modao stream in Yunyang presented a trend of fluctuation, deposited sediment at 160-165 m elevation was coarser than that at 165-175 m elevation,volume percent of sand and clay presented a moderate variation at both altitudes, while silt had small variation. Independent sample t test showed that characteristics difference between the upper and lower sediments in riparian zone was not significant. The geo-accumulation index of heavy metal pollutants in the sediment from riparian zone of the Three Gorges Reservoir tributaries bay indicated that, only Zn element in Zhenxi River, Longdong River and Long River, Pb element in the Modao Stream belonged to non-moderate pollution levels, whereas there were no pollution of all other elements in tributaries. PMID:27337884

  17. Differential Carbon and Nitrogen Controls of Denitrification in Riparian Zones and Streams along an Urban to Exurban Gradient.

    PubMed

    Waters, Emily R; Morse, Jennifer L; Bettez, Neil D; Groffman, Peter M

    2014-05-01

    Denitrification is an anaerobic microbial process that transforms nitrate (NO) to nitrogen (N) gas, preventing the movement of NO into coastal waters where it can lead to eutrophication. Urbanization can reduce the potential for denitrification in riparian zones and streams by altering the environmental conditions that foster denitrification (i.e., low oxygen and available C). Here we evaluated the factors limiting denitrification potential in forested and herbaceous riparian and stream pool and organic debris dam habitats in urban, suburban, exurban, and forested reference watersheds in the Baltimore, Maryland metropolitan area. Denitrification potential (with and without C and NO additions) and microbial biomass C and N content, potential net N mineralization and nitrification, microbial respiration, and inorganic N pools were measured in summer (June) and fall (November). Denitrification potentials were highest in the herbaceous riparian soils and lowest in pool sediments. Forested riparian soil denitrification potential was highest in the exurban watershed but in other habitats did not vary with watershed type. Nearly all variables were higher in June than in November. Overall, C was a more important driver of denitrification potential than N; potentials in unamended and N-amended treatments were very similar (<200 ng N g h) and were much lower than in the C-amended and C+N-amended treatments (>800 ng N g h). Our results suggest that efforts to enhance denitrification in urban watersheds need to focus on the differential controls of denitrification across habitats, urban land use types, and seasons. PMID:25602824

  18. Riparian buffer zones on selected rivers in Lower Silesia - an important conservation practice and the management strategy in urban planning

    NASA Astrophysics Data System (ADS)

    Adamska, Maryna

    2013-09-01

    Buffer zones are narrow strips of land lying along the surface water, covered with appropriately selected vegetation. They separate aquatic ecosystems from the direct impact of agricultural land and reduce the movement of nutrients in the environment. In 2008 the European Commission established requirements for the implementation of buffer strips along water courses. Poland committed to the enforcement of these requirements until 1 January 2012. This was one of the reasons of this study. The subject of the analysis included the following rivers in Lower Silesia: Smortawa, Krynka, Czarna Woda and the selected transects of Ślęza and Nysa Łużycka. Detailed studies were designed to estimate the buffer zones occurring on these watercourses and assess these zones’ structure. This will be used to develop clear criteria for the selection of the width of these zones based on land use land management. It can be used in the implementation of executive acts at different levels of space management. Field research consisted of inventory the extent of riparian buffer strips on selected water courses and photographic documentation. Species composition of the vegetation forming a buffer zone was identified by using Braun-Blanquet method. There was lack of continuity of the riparian buffer zones on investigated rivers. Buffer zones should have carefully formulated definition and width because they are element of the significant ecological value, they perform important environmental protective functions and they are also the subject of Community law.

  19. Potential for long-term transfer of dissolved organic carbon from riparian zones to streams in boreal catchments.

    PubMed

    Ledesma, José L J; Grabs, Thomas; Bishop, Kevin H; Schiff, Sherry L; Köhler, Stephan J

    2015-08-01

    Boreal regions store most of the global terrestrial carbon, which can be transferred as dissolved organic carbon (DOC) to inland waters with implications for both aquatic ecology and carbon budgets. Headwater riparian zones (RZ) are important sources of DOC, and often just a narrow 'dominant source layer' (DSL) within the riparian profile is responsible for most of the DOC export. Two important questions arise: how long boreal RZ could sustain lateral DOC fluxes as the sole source of exported carbon and how its hydromorphological variability influences this role. We estimate theoretical turnover times by comparing carbon pools and lateral exports in the DSL of 13 riparian profiles distributed over a 69 km(2) catchment in northern Sweden. The thickness of the DSL was 36 ± 18 (average ± SD) cm. Thus, only about one-third of the 1-m-deep riparian profile contributed 90% of the lateral DOC flux. The 13 RZ exported 8.7 ± 6.5 g C m(-2) year(-1) , covering the whole range of boreal stream DOC exports. The variation could be explained by local hydromorphological characteristics including RZ width (R(2) = 0.90). The estimated theoretical turnover times were hundreds to a few thousands of years, that is there is a potential long-lasting supply of DOC. Estimates of net ecosystem production in the RZ suggest that lateral fluxes, including both organic and inorganic C, could be maintained without drawing down the riparian pools. This was supported by measurements of stream DO(14) C that indicated modern carbon as the predominant fraction exported, including streams disturbed by ditching. The transfer of DOC into boreal inland waters from new and old carbon sources has a major influence on surface water quality and global carbon balances. This study highlights the importance of local variations in RZ hydromorphology and DSL extent for future DOC fluxes under a changing climate.

  20. Spatial and temporal variability in nitrous oxide and methane emissions in urban riparian zones of the Pearl River Delta.

    PubMed

    Zhang, Taiping; Huang, Xinyu; Yang, Yue; Li, Yuelin; Dahlgren, Randy A

    2016-01-01

    Spatial and temporal variability in nitrous oxide and methane emissions were quantified in three seasons using closed chambers in three riparian zone locations of three branches of the Pearl River, Guangzhou, China. The sampling sites were selected in a rapidly developing urban area of Guangzhou and represented a pollution gradient. The results show that urban riparian landscapes can be large source areas for CH4 and N2O, with fluxes of -0.035∼32.30 mg m(-2) h(-1) and -5.49∼37.31 μg m(-2) h(-1), respectively. River water quality, sediment texture, and NH4-N and NO3-N concentrations correlated with N2O and CH4 emission rates. The riparian zones of the more seriously polluted tributaries showed higher greenhouse gas fluxes than that of the less polluted main stem of the Pearl River. Rain events increased emissions of CH4 by 6.5∼21.3 times and N2O by 2.2∼5.7 times. The lower concentrations of heavy metals increased the activity of denitrifying enzymes while inhibited the methane producing pathways. This work demonstrates that rapidly developing urban areas are an important source of greenhouse gas emissions, which is conditioned by various environmental factors.

  1. Spatial and temporal variability in nitrous oxide and methane emissions in urban riparian zones of the Pearl River Delta.

    PubMed

    Zhang, Taiping; Huang, Xinyu; Yang, Yue; Li, Yuelin; Dahlgren, Randy A

    2016-01-01

    Spatial and temporal variability in nitrous oxide and methane emissions were quantified in three seasons using closed chambers in three riparian zone locations of three branches of the Pearl River, Guangzhou, China. The sampling sites were selected in a rapidly developing urban area of Guangzhou and represented a pollution gradient. The results show that urban riparian landscapes can be large source areas for CH4 and N2O, with fluxes of -0.035∼32.30 mg m(-2) h(-1) and -5.49∼37.31 μg m(-2) h(-1), respectively. River water quality, sediment texture, and NH4-N and NO3-N concentrations correlated with N2O and CH4 emission rates. The riparian zones of the more seriously polluted tributaries showed higher greenhouse gas fluxes than that of the less polluted main stem of the Pearl River. Rain events increased emissions of CH4 by 6.5∼21.3 times and N2O by 2.2∼5.7 times. The lower concentrations of heavy metals increased the activity of denitrifying enzymes while inhibited the methane producing pathways. This work demonstrates that rapidly developing urban areas are an important source of greenhouse gas emissions, which is conditioned by various environmental factors. PMID:26377967

  2. The role of habitat factors in successful invasion of alien plant Acer negundo in riparian zones.

    NASA Astrophysics Data System (ADS)

    Sikorski, Piotr; Sikorska, Daria

    2016-04-01

    Ash-leaved maple (Acer negundo) is one of the most invasive species occurring in riparian zones. The invasion is especially effective in disturbed areas, as the plant favours anthropogenic sites. The plant was also observed to be able to penetrate into sandy bars, also those separated from the land, inaccessible to people. It's removal is time-consuming and laborious, often involves damage done to sensitive vegetation and the results are doubtful, as the plant quickly regenerates. The invasion patterns and establishment of ash-leaved maple in natural ecosystems are poorly investigated. The aim of this study was to test how habitat factors such as: light availability, soil characteristics and competition contribute to ash-leaved maple effective colonization of natural sand bars free from anthropogenic pressure. In 2014 sand bars located in Vistula River Valley in Warsaw were inventoried and classified basing on their development stage as 1 - initial, 2 - unstable, 3 - stable. Apart from the occurrence of the invasive ash-leaved maple the plants competing with it were recognized and the percentage of the shoots of shrubs and herbaceous plants was estimated. PAR was measured at ground level and 1 meter above ground, the thickness of organic layer formed on the top of the sand was also measured as the indicator of sand bar development stage. The maple's survival in extremely difficult conditions resembles the strategy of willows and poplars naturally occurring in the riparian zones, which are well adapted to this environment. The success of invasion strongly depends on the plants establishment during sand bars initial stage of development. The seedlings growth correlates with the age of the sand bar (r1=0,41, r2=0,42 i r3=0,57). The colonization lasts for 4-6 years and the individuals start to cluster in bigger parches. After that period the maple turns into the phase of competition for space. Habitat factors such as shading (r2=0,41 i r3=0,51) and organic layer

  3. 76 FR 30023 - Pamlico Sound and Adjacent Waters, NC; Danger Zones for Marine Corps Operations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ..., 2010, issue of the Federal Register (75 FR 65278) with the docket number COE-2010-0037 and one comment... of Engineers, Department of the Army 33 CFR Part 334 Pamlico Sound and Adjacent Waters, NC; Danger.... SUMMARY: The U.S. Army Corps of Engineers is amending its regulations to establish a new danger zone....

  4. Influences of the unsaturated, saturated, and riparian zones on the transport of nitrate near the Merced River, California, USA

    USGS Publications Warehouse

    Domagalski, J.L.; Phillips, S.P.; Bayless, E.R.; Zamora, C.; Kendall, C.; Wildman, R.A.; Hering, J.G.

    2008-01-01

    Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was transported through a 6.5-m unsaturated zone. Transport times from recharge locations to the edge of a riparian zone ranged from approximately 6 months to greater than 100 years. This allowed for partial denitrification in horizons having mildly reducing conditions, and essentially no denitrification in horizons with oxidizing conditions. Transport times across a 50-100-m-wide riparian zone of less than a year to over 6 years and more strongly reducing conditions resulted in greater rates of denitrification. Isotopic measurements and concentrations of excess N2 in water were indicative of denitrification with the highest rates below the Merced River. Discharge of water and nitrate into the river was dependent on gradients driven by irrigation or river stage. The results suggest that the assimilative capacity for nitrate of the groundwater system, and particularly the riverbed, is limiting the nitrate load to the Merced River in the study area. ?? Springer-Verlag 2007.

  5. Influences of the unsaturated, saturated, and riparian zones on the transport of nitrate near the Merced River, California, USA

    NASA Astrophysics Data System (ADS)

    Domagalski, Joseph L.; Phillips, Steven P.; Bayless, E. Randall; Zamora, Celia; Kendall, Carol; Wildman, Richard A.; Hering, Janet G.

    2008-06-01

    Transport and transformation of nitrate was evaluated along a 1-km groundwater transect from an almond orchard to the Merced River, California, USA, within an irrigated agricultural setting. As indicated by measurements of pore-water nitrate and modeling using the root zone water quality model, about 63% of the applied nitrogen was transported through a 6.5-m unsaturated zone. Transport times from recharge locations to the edge of a riparian zone ranged from approximately 6 months to greater than 100 years. This allowed for partial denitrification in horizons having mildly reducing conditions, and essentially no denitrification in horizons with oxidizing conditions. Transport times across a 50-100-m-wide riparian zone of less than a year to over 6 years and more strongly reducing conditions resulted in greater rates of denitrification. Isotopic measurements and concentrations of excess N2 in water were indicative of denitrification with the highest rates below the Merced River. Discharge of water and nitrate into the river was dependent on gradients driven by irrigation or river stage. The results suggest that the assimilative capacity for nitrate of the groundwater system, and particularly the riverbed, is limiting the nitrate load to the Merced River in the study area.

  6. Hydrogeologic controls on the transport and fate of nitrate in ground water beneath riparian buffer zones: Results from thirteen studies across the United States

    USGS Publications Warehouse

    Puckett, L.J.

    2004-01-01

    During the last two decades there has been growing interest in the capacity of riparian buffer zones to remove nitrate from ground waters moving through them. Riparian zone sediments often contain organic carbon, which favors formation of reducing conditions that can lead to removal of nitrate through denitrification. Over the past decade the National Water Quality Assessment (NAWQA) Program has investigated the transport and fate of nitrate in ground and surface waters in study areas across the United States. In these studies riparian zone efficiency in removing nitrate varied widely as a result of variations in hydrogeologic factors. These factors include (1) denitrification in the up-gradient aquifer due to the presence of organic carbon or other electron donors, (2) long residence times (>50 years) along ground-water flow paths allowing even slow reactions to completely remove nitrate, (3) dilution of nitrate enriched waters with older water having little nitrate, (4) bypassing of riparian zones due to extensive use of drains and ditches, and (5) movement of ground water along deep flow paths below reducing zones. By developing a better understanding of the hydrogeologic settings in which riparian buffer zones are likely to be inefficient we can develop improved nutrient management plans. ?? US Government 2004.

  7. Denitrification potential in stormwater control structures and natural riparian zones in an urban landscape.

    PubMed

    Bettez, Neil D; Groffman, Peter M

    2012-10-16

    Humans have significantly altered urban landscapes, creating impervious surfaces, and changing drainage patterns that increase volume and velocity as well as frequency and timing of runoff following precipitation events. These changes in runoff have impaired streams and riparian areas that previously reduced watershed nitrogen (N) flux through uptake and denitrification. Stormwater control measures (SCM) are used most frequently to mitigate these hydrologic impacts. While SCM control runoff, their ability to remove N compared to natural riparian areas is not well-known. In this study we compared potential denitrification [as denitrification enzyme activity (DEA)] in five types of SCM (wet ponds, dry detention ponds, dry extended detention, infiltration basin, and filtering practices) and forested and herbaceous riparian areas in Baltimore, MD. DEA was higher in SCM (1.2 mg N kg(-1) hr(-1)) than in riparian areas (0.4 mg N kg(-1) hr(-1)). While DEA was highly correlated with soil moisture, organic matter, microbial biomass, and soil respiration areas across sites, it was always higher in SCM at equivalent levels of these variables. SCM appear to function as denitrification hotspots and, despite having similar microbial biomass, have higher potential denitrification than natural riparian areas.

  8. [Transportation and risk assessment of heavy metal pollution in water-soil from the Riparian Zone of Daye Lake, China].

    PubMed

    Zhang, Jia-quan; Li, Xiu; Zhang, Quan-fa; Li, Qiong; Xiao, Wen-sheng; Wang, Yong-kui; Zhang, Jian-chun; Gai, Xi-guang

    2015-01-01

    Each 20 water samples and soil samples (0-10 cm, 10-20 cm) were collected from the riparian zone of Daye Lake in dry season during March 2013. Heavy metals (Cu, Ph, Cd, Zn) have been detected by flame atomic absorption spectrometric (FAAS). The results showed that the average concentrations of Cu, Pb, Cd, Zn in the water were 7.14, 25.94, 15.72 and 37.58 microg x L(-1), respectively. The concentration of Cu was higher than the five degree of the surface water environment quality standard. The average concentrations of Cu, Pb, Cd, Zn in soil(0-10 cm) were 108.38, 53.92, 3.55, 139.26 mg x kg(-1) in soil (10-20 cm) were 93.00, 51.72, 2.08, 171.00 mg x kg(-1), respectively. The Cd concentrations were higher than the three grade value of the national soil environment quality standard. The transportation of Pb from soil to water was relatively stable, and Zn was greatly influenced by soil property and the surrounding environment from soil to water. The transformation of heavy metal in west riparian zone was higher than that of east riparian zone. The potential environmental risk was relatively high. Cu, Pb, Cd, Zn were dominated by residue fraction of the modified BCR sequential extraction method. The overall migration order of heavy metal element was: Pb > Cu > Cd > Zn. There were stronger transformation and higher environmental pollution risk of Cu, Pb. The index of assessment and potential ecological risk coefficient indicated that heavy metal pollution in soil (0-10 cm) was higher than the soil (10-20 cm), Cd was particularly serious.

  9. Combining SAR with LANDSAT for Change Detection of Riparian Buffer Zone in a Semi-arid River Basin

    NASA Astrophysics Data System (ADS)

    Chang, N.

    2006-12-01

    A combination of RADARSAT-1 and Landsat 5 TM satellite images linking the soil moisture variation with Normalized Difference Vegetation Index (NDVI) measurements were used to accomplish remotely sensed change detection of riparian buffer zone in the Choke Canyon Reservoir Watershed (CCRW), South Texas. The CCRW was selected as the study area contributing to the reservoir, which is mostly agricultural and range land in a semi-arid coastal environment. This makes the study significant due to the interception capability of non-point source impact within the riparian buffer zone and the maintenance of ecosystem integrity region wide. First of all, an estimation of soil moisture using RADARSAT-1 Synthetic Aperture Radar (SAR) satellite imagery was conducted. With its all-weather capability, the RADARSAT-1 is a promising tool for measuring the surface soil moisture over seasons. The time constraint is almost negligible since the RADARSAT-1 is able to capture surface soil moisture over a large area in a matter of seconds, if the area is within its swath. RADARSAT-1 images presented at here were captured in two acquisitions, including April and September 2004. With the aid of five corner reflectors deployed by Alaska Satellite Facility (ASF), essential radiometric and geometric calibrations were performed to improve the accuracy of the SAR imagery. The horizontal errors were reduced from initially 560 meter down to less than 5 meter at the best try. Then two Landsat 5 TM satellite images were summarized based on its NDVI. The combination of and NDVI and SAR data obviously show that soil moisture and vegetation biomass wholly varies in space and time in the CCRW leading to identify the riparian buffer zone evolution over seasons. It is found that the seasonal soil moisture variation is highly tied with the NDVI values and the change detection of buffer zone is technically feasible. It will contribute to develop more effective management strategies for non-point source

  10. Host plant shifts and transitions into new adaptive zones in leafhoppers:
    the example of Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae)
    of Russia and adjacent countries.

    PubMed

    Tishechkin, Dmitri Yu

    2016-06-08

    The modes of diversification of Palaearctic Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae) are reconstructed based on data on their host plants and distribution in Russia and the adjacent territories. Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae) is originally an Oriental group, which penetrated into the Palaearctic from Southeast Asia. The genus Pediopsoides and species of the genus Macropsis that feed on East Asian oaks have not dispersed beyond broadleaf forests of the Eastern Palaearctic. Apparently, Pediopsis and elm-feeding species of Macropsis initially dispersed throughout the entire broadleaf forest zone. Division of this zone into two widely separated parts in temperate areas of Europe and East Asia (nemoral disjunction), produced closely related vicariant pairs of sister species. The genus Oncopsis and species of Macropsis feeding on Salicaceae dispersed throughout the entire Palaearctic following their host plants. Both lineages penetrated into riparian forests of the foothills and midlands of Central Asia, where they produced endemic species. The Central Asian Macropsis lineage shifted from Salicaceae to trees and shrubs of unrelated families (wild roses, barberry, oleaster, and sea-buckthorn) growing in the same biotopes. Subsequent diversification on those plants produced several separate host-associated species-groups, some of which penetrated following their hosts from riparian forests into arid habitats. One such lineage apparently shifted from shrubs to wormwood species (Artemisia spp.) and thus gave rise to the genus Macropsidius. This genus underwent adaptive radiation on wormwood species in the plains of South Kazakhstan and Central Asia; advancing westward, it formed secondary centres of diversity in Transcaucasia and the Mediterranean. Finally, some lineage of Macropsidius (or its sister-group) switched from feeding on Artemisia to polyphagy, yielding the ancestral form of the genus Hephathus. In general, the evolution of

  11. Host plant shifts and transitions into new adaptive zones in leafhoppers:
    the example of Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae)
    of Russia and adjacent countries.

    PubMed

    Tishechkin, Dmitri Yu

    2016-01-01

    The modes of diversification of Palaearctic Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae) are reconstructed based on data on their host plants and distribution in Russia and the adjacent territories. Macropsinae (Homoptera: Auchenorrhyncha: Cicadellidae) is originally an Oriental group, which penetrated into the Palaearctic from Southeast Asia. The genus Pediopsoides and species of the genus Macropsis that feed on East Asian oaks have not dispersed beyond broadleaf forests of the Eastern Palaearctic. Apparently, Pediopsis and elm-feeding species of Macropsis initially dispersed throughout the entire broadleaf forest zone. Division of this zone into two widely separated parts in temperate areas of Europe and East Asia (nemoral disjunction), produced closely related vicariant pairs of sister species. The genus Oncopsis and species of Macropsis feeding on Salicaceae dispersed throughout the entire Palaearctic following their host plants. Both lineages penetrated into riparian forests of the foothills and midlands of Central Asia, where they produced endemic species. The Central Asian Macropsis lineage shifted from Salicaceae to trees and shrubs of unrelated families (wild roses, barberry, oleaster, and sea-buckthorn) growing in the same biotopes. Subsequent diversification on those plants produced several separate host-associated species-groups, some of which penetrated following their hosts from riparian forests into arid habitats. One such lineage apparently shifted from shrubs to wormwood species (Artemisia spp.) and thus gave rise to the genus Macropsidius. This genus underwent adaptive radiation on wormwood species in the plains of South Kazakhstan and Central Asia; advancing westward, it formed secondary centres of diversity in Transcaucasia and the Mediterranean. Finally, some lineage of Macropsidius (or its sister-group) switched from feeding on Artemisia to polyphagy, yielding the ancestral form of the genus Hephathus. In general, the evolution of

  12. ISOTOPE EVALUATION OF NITRATE ATTENUATION IN RESTORED AND NATIVE RIPARIAN ZONES IN THE KANKAKEE WATERSHED, INDIANA

    EPA Science Inventory

    Isotopic analyses of oxygen and hydrogen of water ( 18O and D) and nitrogen and oxygen of nitrate ( 15N and 18O) are used in conjunction with conventional water chemistry and hydrologic measurements to investigate water flow and nitrogen cycling mechanisms through two riparian ...

  13. Spatial behavior and distribution of cattle grazing riparian zones in northeastern Oregon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to document and quantify the spatial movement of cattle grazing riparian pastures so that accurate assessment of use and ecological interaction can be made. Track logs with 1 second data collection intervals indicate that cows spent about 63% of their time stationar...

  14. Noise-driven cooperative dynamics between vegetation and topography in riparian zones

    NASA Astrophysics Data System (ADS)

    Vesipa, R.; Camporeale, C.; Ridolfi, L.

    2015-10-01

    Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation-sediments-stream determines the ecogeomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In order to elucidate how randomness shape riparian transects, a stochastic model that takes into account the main links between vegetation, sediments, and the stream is adopted, emphasizing the capability of vegetation to alter the plot topography. A minimalistic approach is pursued, and the probability density function of vegetation biomass is analytically evaluated in any transect plot. This probability density function strongly depends on the vegetation-topography feedback. We demonstrate how the vegetation-induced modifications of the bed topography create more suitable conditions for the survival of vegetation in a stochastically dominated environment.

  15. River Food Web Response to Large-Scale Riparian Zone Manipulations

    PubMed Central

    Wootton, J. Timothy

    2012-01-01

    Conservation programs often focus on select species, leading to management plans based on the autecology of the focal species, but multiple ecosystem components can be affected both by the environmental factors impacting, and the management targeting, focal species. These broader effects can have indirect impacts on target species through the web of interactions within ecosystems. For example, human activity can strongly alter riparian vegetation, potentially impacting both economically-important salmonids and their associated river food web. In an Olympic Peninsula river, Washington state, USA, replicated large-scale riparian vegetation manipulations implemented with the long-term (>40 yr) goal of improving salmon habitat did not affect water temperature, nutrient limitation or habitat characteristics, but reduced canopy cover, causing reduced energy input via leaf litter, increased incident solar radiation (UV and PAR) and increased algal production compared to controls. In response, benthic algae, most insect taxa, and juvenile salmonids increased in manipulated areas. Stable isotope analysis revealed a predominant contribution of algal-derived energy to salmonid diets in manipulated reaches. The experiment demonstrates that riparian management targeting salmonids strongly affects river food webs via changes in the energy base, illustrates how species-based management strategies can have unanticipated indirect effects on the target species via the associated food web, and supports ecosystem-based management approaches for restoring depleted salmonid stocks. PMID:23284786

  16. River food web response to large-scale riparian zone manipulations.

    PubMed

    Wootton, J Timothy

    2012-01-01

    Conservation programs often focus on select species, leading to management plans based on the autecology of the focal species, but multiple ecosystem components can be affected both by the environmental factors impacting, and the management targeting, focal species. These broader effects can have indirect impacts on target species through the web of interactions within ecosystems. For example, human activity can strongly alter riparian vegetation, potentially impacting both economically-important salmonids and their associated river food web. In an Olympic Peninsula river, Washington state, USA, replicated large-scale riparian vegetation manipulations implemented with the long-term (>40 yr) goal of improving salmon habitat did not affect water temperature, nutrient limitation or habitat characteristics, but reduced canopy cover, causing reduced energy input via leaf litter, increased incident solar radiation (UV and PAR) and increased algal production compared to controls. In response, benthic algae, most insect taxa, and juvenile salmonids increased in manipulated areas. Stable isotope analysis revealed a predominant contribution of algal-derived energy to salmonid diets in manipulated reaches. The experiment demonstrates that riparian management targeting salmonids strongly affects river food webs via changes in the energy base, illustrates how species-based management strategies can have unanticipated indirect effects on the target species via the associated food web, and supports ecosystem-based management approaches for restoring depleted salmonid stocks.

  17. River food web response to large-scale riparian zone manipulations.

    PubMed

    Wootton, J Timothy

    2012-01-01

    Conservation programs often focus on select species, leading to management plans based on the autecology of the focal species, but multiple ecosystem components can be affected both by the environmental factors impacting, and the management targeting, focal species. These broader effects can have indirect impacts on target species through the web of interactions within ecosystems. For example, human activity can strongly alter riparian vegetation, potentially impacting both economically-important salmonids and their associated river food web. In an Olympic Peninsula river, Washington state, USA, replicated large-scale riparian vegetation manipulations implemented with the long-term (>40 yr) goal of improving salmon habitat did not affect water temperature, nutrient limitation or habitat characteristics, but reduced canopy cover, causing reduced energy input via leaf litter, increased incident solar radiation (UV and PAR) and increased algal production compared to controls. In response, benthic algae, most insect taxa, and juvenile salmonids increased in manipulated areas. Stable isotope analysis revealed a predominant contribution of algal-derived energy to salmonid diets in manipulated reaches. The experiment demonstrates that riparian management targeting salmonids strongly affects river food webs via changes in the energy base, illustrates how species-based management strategies can have unanticipated indirect effects on the target species via the associated food web, and supports ecosystem-based management approaches for restoring depleted salmonid stocks. PMID:23284786

  18. [Relationship between groundwater quality index of nutrition element and organic matter in riparian zone and water quality in river].

    PubMed

    Hua-Shan, Xu; Tong-Qian, Zhao; Hong-Q, Meng; Zong-Xue, Xu; Chao-Hon, Ma

    2011-04-01

    Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that there will be great risk of nitrogen, phosphorus, nitrate nitrogen and organic matter permeating into the groundwater if floodplain changes into farmland. As the special control unit of nitrogen pollution between rivers and artificial wetlands, dry fanning areas near the river play a very important role in nitrogen migration between river and groundwater. Farm manure as base fertilizer may he an important source of phosphorus leak and loss at the artificial wetlands. Phosphorus leaks into the groundwater and is transferred along the hydraulic gradient, especially during the period of regulation for water and sediment at the Xiaolangdi Reservoir. The land use types and farming systems of the riparian floodplain have a major impact on the nitrate nitrogen contents of the groundwater. Nitrogen can infiltrate and accumulate quickly at anaerobic conditions in the fish pond area, and the annual nitrogen achieves a relatively balanced state in lotus area. In those areas, the soil is flooded and at anaerobic condition in spring and summer, nitrogen infiltrates and denitrification significantly, but soil is not flooded and at aerobic condition in the autumn and winter, and during these time, a significant nitrogen nitrification process occurs. In the area between 50 m and 200 m from the river

  19. [Relationship between groundwater quality index of nutrition element and organic matter in riparian zone and water quality in river].

    PubMed

    Hua-Shan, Xu; Tong-Qian, Zhao; Hong-Q, Meng; Zong-Xue, Xu; Chao-Hon, Ma

    2011-04-01

    Riparian zone hydrology is dominated by shallow groundwater with complex interactions between groundwater and surface water. There are obvious relations of discharge and recharge between groundwater and surface water. Flood is an important hydrological incident that affects groundwater quality in riparian zone. By observing variations of physical and chemical groundwater indicators in riparian zone at the Kouma section of the Yellow River Wetland, especially those took place in the period of regulation for water and sediment at the Xiaolangdi Reservoir, relationship between the groundwater quality in riparian zone and the flood water quality in the river is studied. Results show that there will be great risk of nitrogen, phosphorus, nitrate nitrogen and organic matter permeating into the groundwater if floodplain changes into farmland. As the special control unit of nitrogen pollution between rivers and artificial wetlands, dry fanning areas near the river play a very important role in nitrogen migration between river and groundwater. Farm manure as base fertilizer may he an important source of phosphorus leak and loss at the artificial wetlands. Phosphorus leaks into the groundwater and is transferred along the hydraulic gradient, especially during the period of regulation for water and sediment at the Xiaolangdi Reservoir. The land use types and farming systems of the riparian floodplain have a major impact on the nitrate nitrogen contents of the groundwater. Nitrogen can infiltrate and accumulate quickly at anaerobic conditions in the fish pond area, and the annual nitrogen achieves a relatively balanced state in lotus area. In those areas, the soil is flooded and at anaerobic condition in spring and summer, nitrogen infiltrates and denitrification significantly, but soil is not flooded and at aerobic condition in the autumn and winter, and during these time, a significant nitrogen nitrification process occurs. In the area between 50 m and 200 m from the river

  20. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

    PubMed

    Miller, J J; Bremer, E; Curtis, T

    2016-07-01

    Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding.

  1. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

    PubMed

    Miller, J J; Bremer, E; Curtis, T

    2016-07-01

    Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding. PMID:27380095

  2. Using chemical, hydrologic, and age dating analysis to delineate redox processes and flow paths in the riparian zone of a glacial outwash aquifer-stream system

    USGS Publications Warehouse

    Puckett, L.J.; Cowdery, T.K.; McMahon, P.B.; Tornes, L.H.; Stoner, J.D.

    2002-01-01

    A combination of chemical and dissolved gas analyses, chlorofluorocarbon age dating, and hydrologic measurements were used to determine the degree to which biogeochemical processes in a riparian wetland were responsible for removing NO3- from groundwaters discharging to the Otter Tail River in west central Minnesota. An analysis of river chemistry and flow data revealed that NO3- concentrations in the river increased in the lower half of the 8.3 km study reach as the result of groundwater discharge to the river. Groundwater head measurements along a study transect through the riparian wetland revealed a zone of groundwater discharge extending out under the river. On the basis of combined chemical, dissolved gas, age date, and hydrologic results, it was determined that water chemistry under the riparian wetland was controlled largely by upgradient groundwaters that followed flow paths up to 16 m deep and discharged under the wetland, creating a pattern of progressively older, more chemically reduced, low NO3- water the farther one progressed from the edge of the wetland toward the river. These findings pose challenges for researchers investigating biogeochemical processes in riparian buffer zones because the progressively older groundwaters entered the aquifer in earlier years when less NO3- fertilizer was being used. NO3- concentrations originally present in the groundwater had also decreased in the upgradient aquifer as a result of denitrification and progressively stronger reducing conditions there. The resulting pattern of decreasing NO3- concentrations across the riparian zone may be incorrectly interpreted as evidence of denitrification losses there instead of in the upgradient aquifer. Consequently, it is important to understand the hydrogeologic setting and age structure of the groundwaters being sampled in order to avgid misinterpreting biogeochemical processes in riparian zones.

  3. Do beavers promote the invasion of non-native Tamarix in the Grand Canyon riparian zone

    USGS Publications Warehouse

    Mortenson, S.G.; Weisberg, P.J.; Ralston, B.E.

    2008-01-01

    Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding's willow) and Salix exigua Nutt. (coyote willow) are a staple food of beavers. Because Salix competes with the invasive Tamarix ramosissima Ledeb., land mangers are concerned that beavers may cause an increase in Tamarix through selective foraging of Salix. A spatial analysis was conducted to assess whether the presence of beavers correlates with the relative abundance of Salix and Tamarix. These methods were designed to detect a system-wide effect of selective beaver foraging in this large study area (367 linear km of riparian habitat). Beavers, Salix, and Tamarix co-occurred at the broadest scales because they occupied similar riparian habitat, particularly geomorphic reaches of low and moderate resistivity. Once the affinity of Salix for particular reach types was accounted for, the presence of Salix was independent of beaver distribution. However, there was a weak positive association between beaver presence and Salix cover. Salix was limited to geomorphic settings with greater sinuosity and distinct terraces, while Tamarix occurred in sinuous and straighter sections of river channel (cliffs, channel margins) where it dominated the woody species composition. After accounting for covariates representing river geomorphology, the proportion of riparian surfaces covered by Tamarix was significantly greater for sites where beavers were present. This indicates that either Tamarix and beavers co-occur in similar habitats, beavers prefer habitats that have high Tamarix cover, or beavers contribute to Tamarix dominance through selective use of its native woody competitors. The hypothesis that beaver herbivory contributes to Tamarix dominance should be considered further through more

  4. The distance that contaminated aquatic subsidies extend into lake riparian zones

    USGS Publications Warehouse

    Raikow, D.F.; Walters, D.M.; Fritz, K.M.; Mills, M.A.

    2011-01-01

    Consumption of emergent aquatic insects by terrestrial invertebrates is a poorly resolved, but potentially important, mechanism of contaminant flux across ecosystem borders leading to contaminant exposure in terrestrial invertivores. We characterized the spatial extent and magnitude of contaminant transfer from aquatic sediments to terrestrial invertebrate predators by examining riparian araneid spiders, terrestrial insects, and emergent aquatic insects for stable isotopes and polychlorinated biphenyls (PCBs, sum of 141 congeners) at Lake Hartwell, (Clemson, South Carolina, USA). PCB concentrations in aquatic insects were orders of magnitude higher than in terrestrial insects. Aquatic insect consumption by spiders (as indicated by ??13C and ??15N), PCB concentrations in spiders, and aquatic prey availability were greatest at the shoreline and declined inland, while terrestrial prey availability was invariant with distance. These patterns indicate PCB transfer to spiders through consumption of emergent aquatic insects extending to a distance of ???5 m inland. Measurable, but much lower, PCBs were present in insect predators dominated by social wasps up to 30 m inland. These results illustrate the importance of emergent insects as vectors of contaminant transfer from lake sediments to riparian food webs, and that spiders are key predators in this process. ?? 2011 by the Ecological Society of America.

  5. The distance that contaminated aquatic subsidies extend into lake riparian zones.

    PubMed

    Raikow, David F; Walters, David M; Fritz, Ken M; Mills, Marc A

    2011-04-01

    Consumption of emergent aquatic insects by terrestrial invertebrates is a poorly resolved, but potentially important, mechanism of contaminant flux across ecosystem borders leading to contaminant exposure in terrestrial invertivores. We characterized the spatial extent and magnitude of contaminant transfer from aquatic sediments to terrestrial invertebrate predators by examining riparian araneid spiders, terrestrial insects, and emergent aquatic insects for stable isotopes and polychlorinated biphenyls (PCBs, sum of 141 congeners) at Lake Hartwell, (Clemson, South Carolina, USA). PCB concentrations in aquatic insects were orders of magnitude higher than in terrestrial insects. Aquatic insect consumption by spiders (as indicated by delta13C and delta15N), PCB concentrations in spiders, and aquatic prey availability were greatest at the shoreline and declined inland, while terrestrial prey availability was invariant with distance. These patterns indicate PCB transfer to spiders through consumption of emergent aquatic insects extending to a distance of 5 m inland. Measurable, but much lower, PCBs were present in insect predators dominated by social wasps up to 30 m inland. These results illustrate the importance of emergent insects as vectors of contaminant transfer from lake sediments to riparian food webs, and that spiders are key predators in this process.

  6. The influence of abiotic stress and phenotypic plasticity on the distribution of invasive Alternanthera philoxeroides along a riparian zone

    NASA Astrophysics Data System (ADS)

    Pan, Xiaoyun; Geng, Yupeng; Zhang, Wenju; Li, Bo; Chen, Jiakuan

    2006-11-01

    Relatively few studies have compared invasibility and species invasiveness among microhabitats within communities, synchronously. We surveyed the abundance and performance of non-native Alternanthera philoxeroides (Mart.) Griseb. (alligator weed), its co-occurring native congener, Alternanthera sessilis (L.) DC. (sessile joyweed), and other species in a wetland community along a riparian zone in southeast China to test the hypotheses that: i) degree of invasion differs between different types of microhabitats within the community; and ii) microhabitat types that differ in invasibility also differ in soil resource availability or in sediment characteristics likely to affect resource availability; iii) phenotypic plasticity of A. philoxeroides may play a key role in its adaptation to diverse habitats as can be concluded from its extremely low genetic diversity in China. The study riparian zone comprises different types of microhabitats including wet abandoned field, swamp, marsh dunes and gravel dunes. Consistent with these hypotheses, cover of A. philoxeroides was high in abandoned fields (73 ± 2.9%) and swamps (94 ± 1.3%), which had high soil nutrients and water availability. On the contrary, cover of native A. sessilis was relatively high in marsh dunes and grave dunes, which had coarse gravel surfaces, low soil nutrients and low water availability. A. philoxeroides showed greater morphological plasticity in response to habitat variation. In abiotically harsh habitats, stems had limited growth, and were prostrate with weak adventitious roots at nodes, forming thin, scattered patches. In the two richer habitats, the highly branched plants spread over the water or soil surface, supporting dense stronger leaf-bearing stems which grew vertically. The growth pattern of A. sessilis among microhabitats did not exhibit significant variations. These results suggest that morphological plasticity and microhabitat types with high soil resources may facilitate invasions of A

  7. Methane Emission in a Specific Riparian-Zone Sediment Decreased with Bioelectrochemical Manipulation and Corresponded to the Microbial Community Dynamics

    PubMed Central

    Friedman, Elliot S.; McPhillips, Lauren E.; Werner, Jeffrey J.; Poole, Angela C.; Ley, Ruth E.; Walter, M. Todd; Angenent, Largus T.

    2016-01-01

    Dissimilatory metal-reducing bacteria are widespread in terrestrial ecosystems, especially in anaerobic soils and sediments. Thermodynamically, dissimilatory metal reduction is more favorable than sulfate reduction and methanogenesis but less favorable than denitrification and aerobic respiration. It is critical to understand the complex relationships, including the absence or presence of terminal electron acceptors, that govern microbial competition and coexistence in anaerobic soils and sediments, because subsurface microbial processes can effect greenhouse gas emissions from soils, possibly resulting in impacts at the global scale. Here, we elucidated the effect of an inexhaustible, ferrous-iron and humic-substance mimicking terminal electron acceptor by deploying potentiostatically poised electrodes in the sediment of a very specific stream riparian zone in Upstate New York state. At two sites within the same stream riparian zone during the course of 6 weeks in the spring of 2013, we measured CH4 and N2/N2O emissions from soil chambers containing either poised or unpoised electrodes, and we harvested biofilms from the electrodes to quantify microbial community dynamics. At the upstream site, which had a lower vegetation cover and highest soil temperatures, the poised electrodes inhibited CH4 emissions by ∼45% (when normalized to remove temporal effects). CH4 emissions were not significantly impacted at the downstream site. N2/N2O emissions were generally low at both sites and were not impacted by poised electrodes. We did not find a direct link between bioelectrochemical treatment and microbial community membership; however, we did find a correspondence between environment/function and microbial community dynamics. PMID:26793170

  8. Methane Emission in a Specific Riparian-Zone Sediment Decreased with Bioelectrochemical Manipulation and Corresponded to the Microbial Community Dynamics.

    PubMed

    Friedman, Elliot S; McPhillips, Lauren E; Werner, Jeffrey J; Poole, Angela C; Ley, Ruth E; Walter, M Todd; Angenent, Largus T

    2015-01-01

    Dissimilatory metal-reducing bacteria are widespread in terrestrial ecosystems, especially in anaerobic soils and sediments. Thermodynamically, dissimilatory metal reduction is more favorable than sulfate reduction and methanogenesis but less favorable than denitrification and aerobic respiration. It is critical to understand the complex relationships, including the absence or presence of terminal electron acceptors, that govern microbial competition and coexistence in anaerobic soils and sediments, because subsurface microbial processes can effect greenhouse gas emissions from soils, possibly resulting in impacts at the global scale. Here, we elucidated the effect of an inexhaustible, ferrous-iron and humic-substance mimicking terminal electron acceptor by deploying potentiostatically poised electrodes in the sediment of a very specific stream riparian zone in Upstate New York state. At two sites within the same stream riparian zone during the course of 6 weeks in the spring of 2013, we measured CH4 and N2/N2O emissions from soil chambers containing either poised or unpoised electrodes, and we harvested biofilms from the electrodes to quantify microbial community dynamics. At the upstream site, which had a lower vegetation cover and highest soil temperatures, the poised electrodes inhibited CH4 emissions by ∼45% (when normalized to remove temporal effects). CH4 emissions were not significantly impacted at the downstream site. N2/N2O emissions were generally low at both sites and were not impacted by poised electrodes. We did not find a direct link between bioelectrochemical treatment and microbial community membership; however, we did find a correspondence between environment/function and microbial community dynamics. PMID:26793170

  9. Impact of the construction of a large dam on riparian vegetation cover at different elevation zones as observed from remotely sensed data

    NASA Astrophysics Data System (ADS)

    Kellogg, Christopher H.; Zhou, Xiaobing

    2014-10-01

    The impact of the construction of a large dam on riparian vegetation cover can be multifold. How the riparian vegetation cover changes at different elevation zones in response to the construction of a large dam and the subsequent impound of reservoir water is still an open question. In this study, we used satellite remote sensing data integrated with geographic information system (GIS) to monitor vegetation cover change at different riparian elevation zones on a large spatial scale, taking the Three Gorges Dam in China as an example. Due to the large scale of this newly formed reservoir, it is expected to impact the riparian vegetation canopy both directly and indirectly. We chose to monitor vegetation cover changes along the 100 km riparian stretch of river directly upstream of the Three Gorges Dam site, over the construction period of eleven years (2000-2010), using MODIS vegetation indices products, digital elevation model (DEM) data from ASTER, and the time series water level data of the Three Gorges reservoir as the data sources. Results show that non-vegetated area increased in the inundated zone (below 175 m), as expected; area of densely vegetated land cover increased within the elevation zone of 175-775 m and no change in vegetation cover was observed above 775 m in elevation. Regression analysis between the vegetation index data and the reservoir water level shows that increasing water levels have had a negative impact on vegetation cover below 175 m, a positive impact on vegetation cover is limited to the region between 175 and 775 m, and no significant impact was observed above 775 m. MODIS EVI product is less sensitive in mapping non-vegetated land cover change, but more sensitive in mapping vegetated land cover change, caused by the reservoir water level variation; both products are similar in effectively tracking a trend between land cover change in each elevation zone with time or with reservoir water level.

  10. Riparian zone influence on stream water chemistry at different spatial scales: a GIS-based modelling approach, an example for the Dee, NE Scotland.

    PubMed

    Smart, R P; Soulsby, C; Cresser, M S; Wade, A J; Townend, J; Billett, M F; Langan, S

    2001-12-01

    A geographical information system (GIS-ARC/INFO) was used to collate existing spatial data sets on catchment characteristics to predict stream water quality using simple empirical models. The study, based on the river Dee catchment in NE Scotland, found that geological maps and associated geochemical information provided a suitable framework for predicting chemical parameters associated with acidification sensitivity (including alkalinity and base cation concentrations). In particular, it was found that in relatively undisturbed catchments, the parent material and geochemistry of the riparian zone, when combined with a simple hydrological flow path model, could be used to accurately predict stream water chemistry at a range of flows (Q95 to > Q5) and spatial scales (1-1000 km2). This probably reflects the importance of the riparian zone as an area where hydrological inputs to stream systems occur via flow paths in the soil and groundwater zones. Thus, evolution of drainage water chemistry appears to retain the geochemical characteristics of the riparian area as it enters the channel network. In more intensively managed catchments, riparian land use is a further influential factor, which can be incorporated into models to improve predictions for certain base cations. The utility in providing simple hydrochemical models, based on readily available data sets, to assist environmental managers in planning land use in catchment systems is discussed.

  11. Riparian zone influence on stream water chemistry at different spatial scales: a GIS-based modelling approach, an example for the Dee, NE Scotland.

    PubMed

    Smart, R P; Soulsby, C; Cresser, M S; Wade, A J; Townend, J; Billett, M F; Langan, S

    2001-12-01

    A geographical information system (GIS-ARC/INFO) was used to collate existing spatial data sets on catchment characteristics to predict stream water quality using simple empirical models. The study, based on the river Dee catchment in NE Scotland, found that geological maps and associated geochemical information provided a suitable framework for predicting chemical parameters associated with acidification sensitivity (including alkalinity and base cation concentrations). In particular, it was found that in relatively undisturbed catchments, the parent material and geochemistry of the riparian zone, when combined with a simple hydrological flow path model, could be used to accurately predict stream water chemistry at a range of flows (Q95 to > Q5) and spatial scales (1-1000 km2). This probably reflects the importance of the riparian zone as an area where hydrological inputs to stream systems occur via flow paths in the soil and groundwater zones. Thus, evolution of drainage water chemistry appears to retain the geochemical characteristics of the riparian area as it enters the channel network. In more intensively managed catchments, riparian land use is a further influential factor, which can be incorporated into models to improve predictions for certain base cations. The utility in providing simple hydrochemical models, based on readily available data sets, to assist environmental managers in planning land use in catchment systems is discussed. PMID:11763266

  12. Noise-driven cooperative dynamics between vegetation and topography in riparian zones

    NASA Astrophysics Data System (ADS)

    Vesipa, Riccardo; Camporeale, Carlo; Ridolfi, Luca

    2016-04-01

    Riparian ecosystems exhibit complex biotic and abiotic dynamics, where the triad vegetation-sediments-stream determines the eco-geomorphological features of the river landscape. Random fluctuations of the water stage are a key trait of this triad, and a number of behaviors of the fluvial environment can be understood only taking into consideration the role of noise. In fact, in a given plot, vegetation biomass can grow (if the stage is below the plot elevation) or decay (if the stage is above the plot elevation). As a result, biomass exhibits significant temporal variations. In this framework, the capability of vegetation to alter the transect topography (namely, the plot elevation) is crucial. Vegetation can increase the plot elevation by a number of mechanisms (trapping of water- and wind-transported sediment particles, production of organic soil, stabilization of the soil surface). The increment of plot elevation induces the reduction of the plot-specific magnitude, frequency and duration of floods. These more favorable plot-specific hydrological conditions, in turn, induce an increment of biomass. Moreover, the higher the vegetation biomass, the higher the plot elevation increment induced by these mechanisms. In order to elucidate how the stochastically varying water stage and the vegetation-induced topographic alteration shape the bio-morphological characteristics of riparian transects, a stochastic model that takes into account the main links between vegetation, sediments and the stream was adopted. In particular, the capability of vegetation to alter the plot topography was emphasized. In modeling such interactions, the minimalistic approach was pursued. The complex vegetation-sediments-stream interactions were modeled by a set of state-depended stochastic eco-hydraulic equations. The probability density function of vegetation biomass was then analytically evaluated in any transect plot. This pdf strongly depends on the vegetation-topography feedback. We

  13. Catchment controls on water temperature and the development of simple metrics to inform riparian zone management

    NASA Astrophysics Data System (ADS)

    Johnson, Matthew; Wilby, Robert

    2015-04-01

    of thermal refuge could be important in the context of future climate change, potentially maintaining populations of animals excluded from other parts of the river during hot summer months. International management strategies to mitigate rising temperatures tend to focus on the protection, enhancement or creation of riparian shade. Simple metrics derived from catchment landscape models, the heat capacity of water, and modelled solar radiation receipt, suggest that approximately 1 km of deep riparian shading is necessary to offset a 1° C rise in temperature in the monitored catchments. A similar value is likely to be obtained for similar sized rivers at similar latitudes. Trees would take 20 years to attain sufficient height to shade the necessary solar angles. However, 1 km of deep riparian shade will have substantial impacts on the hydrological and geomorphological functioning of the river, beyond simply altering the thermal regime. Consequently, successful management of rising water temperature in rivers will require catchment scale consideration, as part of an integrated management plan.

  14. Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

    USGS Publications Warehouse

    Duff, J.H.; Triska, F.J.

    1990-01-01

    Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

  15. Alteration-weakening leading to localized deformation in a damage aureole adjacent to a dormant shear zone

    NASA Astrophysics Data System (ADS)

    Backeberg, Nils R.; Rowe, Christie D.; Barshi, Naomi

    2016-09-01

    Deformation adjacent to faults and shear zones is traditionally thought to correlate with slip. Inherited structures may control damage geometry, localizing fluid flow and deformation in a damage aureole around structures, even after displacement has ceased. In this paper we document a post-shearing anastomosing foliation and fracture network that developed to one side of the Mesoarchean Marmion Shear Zone. This fracture network hosts the low-grade, disseminated Hammond Reef gold deposit. The shear zone juxtaposed a greenstone belt against tonalite gneiss and was locked by an intrusion that was emplaced during the final stages of suturing. After cessation of activity, fluids channeled along fault- and intrusion-related fractures led to the pervasive sericitization of feldspars. Foliated zones resulted from flattening in the weaker sericite-rich tonalite during progressive alteration without any change in the regional NW-SE shortening direction. The anastomosing pattern may have been inherited from an earlier ductile fabric, but sericite alteration and flattening fabrics all formed post-shearing. Thus, the apparent foliated fracture network adjacent to the Marmion Shear Zone is a second-order effect of shear-related damage, distinct in time from shear activity, adjacent to an effectively dormant shear zone. This phenomenon has implications for understanding the relative timing of fault zone activity, alteration and (in this case) gold mineralization related to long-term fault zone permeability.

  16. Denitrification controls in urban riparian soils: implications for reducing urban nonpoint source nitrogen pollution.

    PubMed

    Li, Yangjie; Chen, Zhenlou; Lou, Huanjie; Wang, Dongqi; Deng, Huanguang; Wang, Chu

    2014-09-01

    The purpose of this research was to thoroughly analyze the influences of environmental factors on denitrification processes in urban riparian soils. Besides, the study was also carried out to identify whether the denitrification processes in urban riparian soils could control nonpoint source nitrogen pollution in urban areas. The denitrification rates (DR) over 1 year were measured using an acetylene inhibition technique during the incubation of intact soil cores from six urban riparian sites, which could be divided into three types according to their vegetation. The soil samples were analyzed to determine the soil organic carbon (SOC), soil total nitrogen (STN), C/N ratio, extractable NO3 (-)-N and NH4 (+)-N, pH value, soil water content (SWC), and the soil nitrification potential to evaluate which of these factors determined the final outcome of denitrification. A nitrate amendment experiment further indicated that the riparian DR was responsive to added nitrate. Although the DRs were very low (0.099 ~ 33.23 ng N2O-N g(-1) h(-1)) due to the small amount of nitrogen moving into the urban riparian zone, the spatial and temporal patterns of denitrification differed significantly. The extractable NO3 (-)-N proved to be the dominant factor influencing the spatial distribution of denitrification, whereas the soil temperature was a determinant of the seasonal DR variation. The six riparian sites could also be divided into two types (a nitrate-abundant and a nitrate-stressed riparian system) according to the soil NO3 (-)-N concentration. The DR in nitrate-abundant riparian systems was significantly higher than that in the nitrate-stressed riparian systems. The DR in riparian zones that were covered with bushes and had adjacent cropland was higher than in grass-covered riparian sites. Furthermore, the riparian DR decreased with soil depth, which was mainly attributed to the concentrated nitrate in surface soils. The DR was not associated with the SOC, STN, C/N ratio, and

  17. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates.

    PubMed

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners.

  18. Tritium Plume Dynamics in the Shallow Unsaturated Zone Adjacent to an Arid Waste Disposal Facility

    NASA Astrophysics Data System (ADS)

    Maples, S.; Andraski, B. J.; Stonestrom, D. A.; Cooper, C. A.; Michel, R. L.; Pohll, G. M.

    2012-12-01

    Previous studies at the U.S. Geological Survey's Amargosa Desert Research Site (ADRS) in southern Nevada have documented two plumes of tritiated water-vapor (3HHOg) adjacent to a closed, commercial low-level radioactive waste disposal facility. Wastes were disposed on-site from 1962-92. Tritium has moved long distances (> 400 m) through a shallow (1-2-m depth) dry gravelly layer—orders of magnitude further than anticipated by standard transport models. Geostatistical methods, spatial moment analyses and tritium flux calculations were applied to assess shallow plume dynamics. A grid-based plant-water sampling method was utilized to infer detailed, field-scale 3HHOg concentrations at 5-yr intervals during 2001-11. Results indicate that gravel-layer 3HHOg mass diminished faster than would be expected from radioactive decay (~70% in 10 yr). Both plumes exhibited center-of-mass stability, suggesting that bulk-plume movement is minimal during the period of study. Nonetheless, evidence of localized lateral advancement along some margins, combined with increases in the spatial covariance of concentration distribution, indicates intra-plume mass redistribution is ongoing. Previous studies have recognized that vertical movement of tritiated water from sub-root-zone gravel into the root-zone contributes to atmospheric release via evapotranspiration. Estimates of lateral and vertical tritium fluxes during the study period indicate (1) vertical tritiated water fluxes were dominated by diffusive-vapor fluxes (> 90%), and (2) vertical diffusive-vapor fluxes were roughly an order of magnitude greater than lateral diffusive-vapor fluxes. This behavior highlights the importance of the atmosphere as a tritium sink. Estimates of cumulative vertical diffusive-vapor flux and radioactive decay with time were comparable to observed declines in total shallow plume mass with time. This suggests observed changes in plume mass may (1) be attributed, in considerable part, to these removal

  19. Does soil water saturation mobilize metals from riparian soils to adjacent surface water? A field monitoring study in a metal contaminated region.

    PubMed

    Van Laer, Liesbeth; Smolders, Erik

    2013-06-01

    In the Noorderkempen (NW Belgium), a large area (about 280 km(2)) is contaminated with cadmium (Cd) and zinc (Zn) due to historical pollution by the Zn smelters. Direct aquatic emissions of metals have diminished over time, however the surface water metal concentration largely exceeds quality standards, mainly during winter periods. Monitoring data were analyzed to reveal whether these fluctuations are related to seasonal redox reactions in associated contaminated riparian soils that drain into the rivers. A field survey was set up with soil pore-water and groundwater monitored for three years in transects of soil monitoring points perpendicular to rivers at contaminated and non-contaminated sites. Site averaged surface water concentrations of a 15 year dataset exceeded local quality standards 4 to 200-fold. Winter averaged metal concentrations significantly exceeded the corresponding summer values 1.3-1.8 (Zn) and 1.5-2.4 fold (Cd). Zinc and Cd concentrations in water were positively related to Fe and Mn but not to Ca, K or Na suggesting that redox reactions and not dilution processes are involved. In ground- and pore-water of the associated riparian soils, the concentrations of Zn fluctuate by the same order of magnitude as in surface water but were generally smaller than in the corresponding contaminated rivers. In addition, correlations of dissolved Zn with Fe and Mn were lacking. This analysis suggests that redox reactions in streams, and not in riparian soils, explain the seasonal trends of Zn and Cd in surface water. Hence, river sediments and not riparian soils may be the cause of the winter peaks of Zn and Cd in these rivers.

  20. Pelagic ciliate communities within the Amundsen Sea polynya and adjacent sea ice zone, Antarctica

    NASA Astrophysics Data System (ADS)

    Jiang, Yong; Liu, Qian; Yang, Eun Jin; Wang, Min; Kim, Tae Wan; Cho, Kyoung-Ho; Lee, SangHoon

    2016-01-01

    Polynyas, areas of open water surrounded by sea ice, are sites of intense primary production and ecological hotspots in the Antarctic Ocean. This study determined the spatial variation in communities of pelagic ciliates in an Amundsen Sea polynya (ASP) and adjacent sea ice zones (SIZ) during austral summer from February to March 2012, and the results were compared with biotic and abiotic environmental factors. The species number, abundance and biomass were higher in the ASP than SIZ. Canonical analysis indicated that the communities in the ASP were distinct from those under the sea ice. The pelagic ciliate community structure was closely correlated with environmental variability. Several primary environmental variables, both alone and in combination, were found to affect community spatial patterns. The ciliate biomasses in the ASP and SIZ areas were both significantly correlated with total and nano-Chl a. This analysis of the ciliated microzooplankton communities associated with high primary production provides new insights into the roles of ciliates in biogeochemical cycles in high-latitude polynyas. Additionally, our findings provide detailed data on the composition, distribution, and structure of polynya ciliate communities in the Amundsen Sea.

  1. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AND RESTRICTED AREA REGULATIONS § 334.410 Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck Sound...°31′00″, longitude 76°01′40″. (2) Northern part of Currituck Sound. Beginning at a point bearing...

  2. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Albemarle Sound, Pamlico Sound... AND RESTRICTED AREA REGULATIONS § 334.410 Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck...

  3. The influence of partial timber harvest in riparian management zones on macroinvertebrate and fish communities on first- and second-order streams in northern Minnesota

    USGS Publications Warehouse

    Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric; Schlesser, Nicholas

    2010-01-01

    Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m2 ha−1 or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m2 ha−1 may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.

  4. [Species specificity of morphogenetic factors of Acetabularia, localized in the cytoplasmic zone adjacent to the cell membrane].

    PubMed

    Naumova, G A; Naumova, L P; Puchkova, L I; Savchenko, S M; Sandakhchiev, L S

    1976-01-01

    The species specificity of the factors controlling the cap development was established in the experiments with the transplantation of both the intact and centrifuged in the basal direction apical regions of Acetabularia meditteranea on nuclear basal regions of A. crenulata. These factors are found at the stage of 72 hrs of regeneration primarily in the cytoplasmic zone adjacent to the cell membrane which is not displaced during centrifugation. Using direct measurements and radiochemical method, we have shown that the accumulation of proteins proceeded in this zone due, mainly, to their transition from the cytoplasmic zone displaced during centrifugation.

  5. Transport and fate of nitrate and pesticides: Hydrogeology and riparian zone processes

    USGS Publications Warehouse

    Puckett, L.J.; Hughes, W.B.

    2005-01-01

    There is continuing concern over potential impacts of widespread application of nutrients and pesticides on ground- and surface-water quality. Transport and fate of nitrate and pesticides were investigated in a shallow aquifer and adjacent stream, Cow Castle Creek, in Orangeburg County, South Carolina. Pesticide and pesticide degradate concentrations were detected in ground water with greatest frequency and largest concentrations directly beneath and downgradient from the corn (Zea mays L.) field where they were applied. In almost all samples in which they were detected, concentrations of pesticide degradates greatly exceeded those of parent compounds, and were still present in ground waters that were recharged during the previous 18 yr. The absence of both parent and degradate compounds in samples collected from deeper in the aquifer suggests that this persistence is limited or that the ground water had recharged before use of the pesticide. Concentrations of NO3- in ground water decreased with increasing depth and age, but denitrification was not a dominant controlling factor. Hydrologic and chemical data indicated that ground water discharges to the creek and chemical exchange takes place within the upper 0.7 m of the streambed. Ground water had its greatest influence on surface-water chemistry during low-flow periods, causing a decrease in concentrations of Cl-, NO3-, pesticides, and pesticide degradates. Conversely, shallow subsurface drainage dominates stream chemistry during high-flow periods, increasing stream concentrations of Cl-, NO3-, pesticides, and pesticide degradates. These results point out the importance of understanding the hydrogeologic setting when investigating transport and fate of contaminants in ground water and surface water. ?? ASA, CSSA, SSSA.

  6. Using biodiversity of diatoms to identify hydrological connectivity in the hillslope-riparian zone-stream system

    NASA Astrophysics Data System (ADS)

    Wetzel, C. E.; Martínez-Carreras, N.; Ector, L.; Hlubikova, D.; Frentress, J.; McDonnell, J. J.; Hoffmann, L.; Pfister, L.

    2012-04-01

    In recent years, there have been increasingly calls for new eco-hydrological approaches to answer questions on water source and connectivity in the landscape. Diatoms are one of the most common and diverse algal groups, and offer the potential for the identification of reproducible flow patterns and a link to underlying watershed behaviour. Our preliminary investigations on the potential for terrestrial diatoms to detect the onset/cessation of surface runoff suggested that diatoms can contribute to confirm or reject the existence of a surface runoff component in total runoff, thereby helping to constrain assumptions made on a potential surface runoff component in a conventional tracer based hydrograph separation. Our investigations currently focus on the Attert River basin (Luxembourg, Europe) and the HJ Andrews experimental forest (Oregon, USA). Here we show results from the schistose Weierbach experimental catchment (0.45 km2), located in the Attert River basin. Ordination analysis revealed a clear distinction between communities belonging to the river bed substrate and the riparian zone. Drift samples corresponding to stream water show a mixed composition of diatoms stemming from the river bed substrate and the riparian zone. Ongoing investigations focus on the composition of hillslope communities. In winter, long-lasting low intensity rainfall events generate a two-tailed hydrograph response of the Weierbach, consisting in an immediate reaction to precipitation, followed by a delayed and much more significant rise of the hydrograph. For these events, mixing diagrams (SiO2 & Absorbance) suggest a substantial contribution of the soil water component to total runoff, with groundwater and especially overland flow remaining insignificant. Terrestrial diatom abundance appeared to be very sensitive to incident precipitation (rising to +/- 15% of the total diatom population), suggesting a rapid connectivity between the soil surface and the stream. In summer, short and

  7. Impact of riparian zone protection from cattle on nutrient, bacteria, F-coliphage, and loading of an intermittent stream.

    PubMed

    Sunohara, M D; Topp, E; Wilkes, G; Gottschall, N; Neumann, N; Ruecker, N; Jones, T H; Edge, T A; Marti, R; Lapen, D R

    2012-01-01

    This 5-yr study compared, via an upstream-downstream experimental design, nutrient and microbial water quality of an intermittent stream running through a small pasture (∼2.5 animals ha) where cattle are restricted from the riparian zone (restricted cattle access [RCA]) and where cattle have unrestricted access to the stream (unrestricted cattle access [URCA]). Fencing in the RCA excluded pasturing cattle to within ∼3 to 5 m of the stream. Approximately 88% (26/32) of all comparisons of mean contaminant load reduction for lower, higher, and all stream flow conditions during the 5-yr study indicated net contaminant load reductions in the RCA; for the URCA, this percentage was 38% (12/32). For all flow conditions, mean percent load reductions in the RCA for nutrients and bacteria plus F-coliphage were 24 and 23%, respectively. These respective percentages for the URCA were -9 and -57% (positive values are reductions; negative values are increases). However, potentially as a result of protected wildlife habitat in the RCA, the mean percent load reduction for for "all flow" was -321% for the RCA and 60% for the URCA; for , these respective percentages were -209% (RCA) and 73% (URCA). For "all flow" situations, mean load reductions for the RCA were significantly greater ( < 0.1) than those from the URCA for NH-N, dissolved reactive phosphorus (DRP), total coliform, , and . For "high flow" situations, mean load reductions were significantly greater for the RCA for DRP, total coliform, and . For "low flow" conditions, significantly greater mean load reductions were in favor of the RCA for DRP, total P, total coliforms, fecal coliforms, , and . In no case were mean pollutant loads in the URCA significantly higher than RCA pollutant loads. Restricting pasturing livestock to within 3 to 5 m of intermittent streams can improve water quality; however, water quality impairment can occur if livestock have unrestricted access to a stream.

  8. Project Work Plan 100-N Area Strontium-90 Treatability Demonstration Project: Phytoremediation Along the 100-N Columbia River Riparian Zone

    SciTech Connect

    Ainsworth, Calvin C.

    2006-04-30

    The 100-N Area Innovative Treatment and Remediation Demonstration (ITRD) identified phyto¬remediation as a potential technology both for the removal of 90Sr from the soil of the riparian zone and as a filter for groundwater along the Columbia River. Recent greenhouse and growth chamber studies have demonstrated the viability of phytoextraction to remove 90Sr from this area’s soil/water; in conjunction with monitored natural attenuation and an apatite barrier the process would make an effective treatment for remediation of the 100-N Area 90Sr plume. All activities associated with the 100-NR-1 and 100-NR-2 Operable Units of the Hanford 100-N Area have had, and continue to have, significant regulatory and stakeholder participation. Beginning in 1998 with the ITRD process, presentations to the ITRD TAG were heavily attended by EPA, Washington State Department of Ecology, and stakeholders. In addition, three workshops have been held to receive regulatory and stakeholder feedback on monitored natural attenuation, the apatite barrier, and phytoremediation; these were held in Richland in August 2003, December 2004, and August 2005. The apatite injection treatability test plan (DOE 2005) describes phytoremediation as a technology to be evaluated during the March 2008 evaluation milestone as described in the Tri-Party Agreement change request (M-16-06-01 Change Control Form). If, during this evaluation milestone, phytoremediation is favorably evaluated it would be incorporated into the treatability test plan. The phytoremediation treatability test described in this proposal is strongly supported by the Washington State Department of Ecology.

  9. Impacts of LUCC on soil properties in the riparian zones of desert oasis with remote sensing data: a case study of the middle Heihe River basin, China.

    PubMed

    Jiang, Penghui; Cheng, Liang; Li, Manchun; Zhao, Ruifeng; Duan, Yuewei

    2015-02-15

    Large-scale changes in land use and land cover over long timescales can induce significant variations in soil physicochemical properties, particularly in the riparian zones of arid regions. Frequent reclamation of wetlands and grasslands and intensive agricultural activity have induced significant changes in both land use/cover and soil physicochemical properties in the riparian zones of the middle Heihe River basin of China. The present study aims to explore whether land use/land cover change (LUCC) can well explain the variations in soil properties in the riparian zones of the middle Heihe River basin. To achieve this, we mapped LUCC and quantified the type of land use change using remote sensing images, topographic maps, and GIS analysis techniques. Forty-two sites were selected for soil and vegetation sampling. Then, physical and chemical experiments were employed to determine soil moisture, soil bulk density, soil pH, soil organic carbon, total nitrogen, total potassium, total phosphorous, available nitrogen, available potassium, and available phosphorous. The Independent-Samples Kruskal-Wallis Test, principal component analysis, and a scatter matrix were used to analyze the effects of LUCC on soil properties. The results indicate that the majority of the parameters investigated were affected significantly by LUCC. In particular, soil moisture and soil organic carbon can be explained well by land cover change and land use change, respectively. Furthermore, changes in soil moisture could be attributed primarily to land cover changes. Changes in soil organic carbon were correlated closely with the following land use change types: wetlands-arable, forest-grasslands, and grasslands-desert. Other parameters, including pH and total K, were also found to exhibit significant correlations with LUCC. However, changes in soil nutrients were shown to be induced most probably by human agricultural activity (i.e. fertilize, irrigation, tillage, etc.), rather than by simple

  10. Impacts of LUCC on soil properties in the riparian zones of desert oasis with remote sensing data: a case study of the middle Heihe River basin, China.

    PubMed

    Jiang, Penghui; Cheng, Liang; Li, Manchun; Zhao, Ruifeng; Duan, Yuewei

    2015-02-15

    Large-scale changes in land use and land cover over long timescales can induce significant variations in soil physicochemical properties, particularly in the riparian zones of arid regions. Frequent reclamation of wetlands and grasslands and intensive agricultural activity have induced significant changes in both land use/cover and soil physicochemical properties in the riparian zones of the middle Heihe River basin of China. The present study aims to explore whether land use/land cover change (LUCC) can well explain the variations in soil properties in the riparian zones of the middle Heihe River basin. To achieve this, we mapped LUCC and quantified the type of land use change using remote sensing images, topographic maps, and GIS analysis techniques. Forty-two sites were selected for soil and vegetation sampling. Then, physical and chemical experiments were employed to determine soil moisture, soil bulk density, soil pH, soil organic carbon, total nitrogen, total potassium, total phosphorous, available nitrogen, available potassium, and available phosphorous. The Independent-Samples Kruskal-Wallis Test, principal component analysis, and a scatter matrix were used to analyze the effects of LUCC on soil properties. The results indicate that the majority of the parameters investigated were affected significantly by LUCC. In particular, soil moisture and soil organic carbon can be explained well by land cover change and land use change, respectively. Furthermore, changes in soil moisture could be attributed primarily to land cover changes. Changes in soil organic carbon were correlated closely with the following land use change types: wetlands-arable, forest-grasslands, and grasslands-desert. Other parameters, including pH and total K, were also found to exhibit significant correlations with LUCC. However, changes in soil nutrients were shown to be induced most probably by human agricultural activity (i.e. fertilize, irrigation, tillage, etc.), rather than by simple

  11. The release of phosphorus to porewater and surface water from river riparian sediments.

    PubMed

    Surridge, Ben W J; Heathwaite, A L; Baird, Andrew J

    2007-01-01

    Sediments can be both a source and a sink of dissolved phosphorus (P) in surface water and shallow groundwater. Using laboratory mesocosms, we studied the influence of flooding with deionized water and simulated river water on P release to solution using sediment columns taken from a riparian wetland. The mesocosm incubation results showed that rather than retaining nutrients, sediments in the riparian zone may be a significant source of P. Concentrations of dissolved P in porewater reached more than 3 mg L(-1) and in surface water over 0.8 mg L(-1) within a month of sediment inundation. The reductive dissolution of P-bearing iron (Fe) oxides was the likely mechanism responsible for P release. Dissolved P to Fe molar ratios in anaerobic samples were approximately 0.45 when columns were flooded with water that simulated the chemistry of the adjacent river. This suggests there was insufficient Fe in the anaerobic samples to precipitate all P if the solutions were oxygenated or transported to an aerobic environment. If the anaerobic wetland solutions were delivered to oxygenated rivers and streams adjacent to the riparian zone, the equilibrium concentration of P in these systems could rise. The timing of P release was inversely related to the nitrate (NO3-) concentration in floodwater. This indicates that in riparian zones receiving low nitrate loads, or where NO3- loads are being progressively reduced, the risk of dissolved P release may increase. These findings present particular challenges for restoration and management in riparian areas.

  12. Assessing the Utility of Green LiDAR for Characterizing Forest Canopy Structure and Stream Bathymetry in Riparian Zones.

    NASA Astrophysics Data System (ADS)

    Moskal, L. M.; Richardson, J.

    2014-12-01

    Forested riparian zones serve many ecosystem functions from species habitat through stream shading and large woody debris recruitment, to improvements in water quality. Moreover, stream depth and bathymetry in forested environments is difficult and costly to measure in the field, but critically important for stream-dwelling organisms. Green (bathymetric) LiDAR (G-L) can be used to characterize stream bathymetry, but little is known of its ability to accurately characterize stream bathymetry in narrow (width less than 5 m), heavily forested streams. Canopy characterization with green LiDAR is also poorly understood. We compared canopy and digital elevation models (DEMs) derived from green and near-infrared LiDAR (NIR-L) to field measurements in a narrow, forested stream in Oregon, USA, as well as comparing the two canopy models and DEMs to each other along the length of the stream and to estimates of leaf area index. We observed that the canopy models from the G-L are lower in accuracy compared to NIR-L canopy models. Canopy height models from the G-L were up to 26% less accurate in dense stands, compared to the NIR-L accuracy of 94%. We attribute these errors in part to the lower quality of DEMs generated from the G-L as compared to the NIR-L DEMs. As for bathymetry, the G-L DEM was 0.05 cm higher in elevation than the field measured stream elevation, while the NIR-L ground model was 0.17mm higher. The elevation difference tended to increase with stream depth for both types of LiDAR-derived DEMs, but stream depth only explained a small portion of the variability (coefficient of determination equals 0.09 for NIR-L DEM and 0.05 for G-L DEM). Our results suggest that G-L may be limited in accurately characterizing the bathymetry of narrow streams in heavily forested environments due to difficulty penetrating canopy and interactions with complex topography.

  13. Postfire logging in riparian areas.

    PubMed

    Reeves, Gordon H; Bisson, Peter A; Rieman, Bruce E; Benda, Lee E

    2006-08-01

    We reviewed the behavior of wildfire in riparian zones, primarily in the western United States, and the potential ecological consequences of postfire logging. Fire behavior in riparian zones is complex, but many aquatic and riparian organisms exhibit a suite of adaptations that allow relatively rapid recovery after fire. Unless constrained by other factors, fish tend to rebound relatively quickly, usually within a decade after a wildfire. Additionally, fire and subsequent erosion events contribute wood and coarse sediment that can create and maintain productive aquatic habitats over time. The potential effects of postfire logging in riparian areas depend on the landscape context and disturbance history of a site; however available evidence suggests two key management implications: (1) fire in riparian areas creates conditions that may not require intervention to sustain the long-term productivity of the aquatic network and (2) protection of burned riparian areas gives priority to what is left rather than what is removed. Research is needed to determine how postfire logging in riparian areas has affected the spread of invasive species and the vulnerability of upland forests to insect and disease outbreaks and how postfire logging will affect the frequency and behavior of future fires. The effectiveness of using postfire logging to restore desired riparian structure and function is therefore unproven, but such projects are gaining interest with the departure of forest conditions from those that existed prior to timber harvest, fire suppression, and climate change. In the absence of reliable information about the potential consequence of postfire timber harvest, we conclude that providing postfire riparian zones with the same environmental protections they received before they burned isjustified ecologically Without a commitment to monitor management experiments, the effects of postfire riparian logging will remain unknown and highly contentious.

  14. Climatic Factors Drive Population Divergence and Demography: Insights Based on the Phylogeography of a Riparian Plant Species Endemic to the Hengduan Mountains and Adjacent Regions

    PubMed Central

    Wang, Zhi-Wei; Chen, Shao-Tian; Nie, Ze-Long; Zhang, Jian-Wen; Zhou, Zhuo; Deng, Tao; Sun, Hang

    2015-01-01

    Quaternary climatic factors have played a significant role in population divergence and demography. Here we investigated the phylogeography of Osteomeles schwerinae, a dominant riparian plant species of the hot/warm-dry river valleys of the Hengduan Mountains (HDM), Qinling Mountains (QLM) and Yunnan-Guizhou Plateau (YGP). Three chloroplast DNA (cpDNA) regions (trnD-trnT, psbD-trnT, petL-psbE), one single copy nuclear gene (glyceraldehyde 3-phosphate dehydrogenase; G3pdh), and climatic data during the Last Interglacial (LIG; c. 120–140 ka), Last Glacial Maximum (LGM; c. 21 ka), and Current (c. 1950–2000) periods were used in this study. Six cpDNA haplotypes and 15 nuclear DNA (nDNA) haplotypes were identified in the 40 populations of O. schwerinae. Spatial Analysis of Molecular Variance, median-joining networks, and Bayesian phylogenetic trees based on the cpDNA and nDNA datasets, all suggested population divergence between the QLM and HDM-YGP regions. Our climatic analysis identified significant heterogeneity of the climatic factors in the QLM and HDM-YGP regions during the aforementioned three periods. The divergence times based on cpDNA and nDNA haplotypes were estimated to be 466.4–159.4 ka and 315.8–160.3 ka, respectively, which coincide with the time of the weakening of the Asian monsoons in these regions. In addition, unimodal pairwise mismatch distribution curves, expansion times, and Ecological Niche Modeling suggested a history of population expansion (rather than contraction) during the last glaciation. Interestingly, the expansion times were found being well consistent with the intensification of the Asian monsoons during this period. We inferred that the divergence between the two main lineages is probably caused by disruption of more continuous distribution because of weakening of monsoons/less precipitation, whilst subsequent intensification of the Asian monsoons during the last glaciation facilitated the expansion of O. schwerinae

  15. Atrazine transport within a coastal zone in Southeastern Puerto Rico: a sensitivity analysis of an agricultural field model and riparian zone management model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water quality models are used to predict effects of conservation practices to mitigate the transport of herbicides to water bodies. We used two models - the Agricultural Policy/Environmental eXtender (APEX) and the Riparian Ecosystem Management Model (REMM) to predict the movement of atrazine from ...

  16. The ecology of riparian habitats of the southern California coastal region: A community profile

    SciTech Connect

    Faber, P.M.; Keller, E.; Sands, A.; Massey, B.M. , Mill Valley, CA; Keller , Santa Barbara, CA; Sands , Mill Valley, CA; Massey , Long Beach, CA )

    1989-09-01

    In the 200 years since California's settlement by Europeans, almost every river in southern California has been channelized or dammed to allow development on the floodplains, causing the loss of a highly productive ecosystem. The riparian zone occurs along streambanks where soils are fertile and water is abundant; amphibians, reptiles, birds, and mammals all move back and forth across the riparian zone from streams into adjacent wetland and upland areas. Irreversible alterations of the riparian ecosystem result from the diversion or loss of transported water to the system through diking, damming, channelization, levee building, or road construction. Clearing for crops, grazing, or golf courses is potentially reversible as long as the water supply remains unaltered. Successful restoration work requires early agreement on project goals, site-specific restoration design, correct project implementation, enforcement of permit conditions, a maintenance and management program, and long-range monitoring. 288 refs., 54 figs., 13 tabs.

  17. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA... Ocean in vicinity of No Mans Land—(1) The area. The waters surrounding No Mans Land within an area... 41°15′30″, longitude 70°51′30″; thence northeasterly to latitude 41°17′30″, longitude...

  18. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA... Ocean in vicinity of No Mans Land—(1) The area. The waters surrounding No Mans Land within an area... 41°15′30″, longitude 70°51′30″; thence northeasterly to latitude 41°17′30″, longitude...

  19. Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters

    NASA Astrophysics Data System (ADS)

    Shan, Xiujuan; Jin, Xianshi; Yuan, Wei

    2010-05-01

    Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters were analyzed based on data from bottom trawl surveys conducted on the R/V Beidou in June, August and October 2006. Four fish assemblages were identified in each survey using two-way indicator species analysis (TWIA). High fish biomass was found in the northern part, central part and coastal waters of the survey area; in contrast, high fish diversity was found in the southern part of the survey area and the Changjiang estuary outer waters. Therefore, it is difficult to maintain high fishery production when high fish diversity is evenly distributed in the fish community. Fish became smaller and fish size spectra tended to be narrower because of fish species variations and differences in growth characteristics. Fish diversity increased, the age to maturity was reduced and some migrant species were not collected in the surveys. Fish with low economic value, small size, simple age structure and low tropic level were predominant in fish assemblages in the Changjiang estuary and its adjacent waters. The lowest hypoxic value decreased in the Changjiang estuary and its adjacent waters.

  20. Trace Element Mobility in Water and Sediments in a Hyporheic Zone Adjacent to an Abandoned Uranium Mine

    NASA Astrophysics Data System (ADS)

    Roldan, C.; Blake, J.; Cerrato, J.; Ali, A.; Cabaniss, S.

    2015-12-01

    The legacy of abandoned uranium mines lead to community concerns about environmental and health effects. This study focuses on a cross section of the Rio Paguate, adjacent to the Jackpile Mine on the Laguna Reservation, west-central New Mexico. Often, the geochemical interactions that occur in the hyporheic zone adjacent to these abandoned mines play an important role in trace element mobility. In order to understand the mobility of uranium (U), arsenic (As), and vanadium (V) in the Rio Paguate; surface water, hyporheic zone water, and core sediment samples were analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). All water samples were filtered through 0.45μm and 0.22μm filters and analyzed. The results show that there is no major difference in concentrations of U (378-496μg/L), As (0.872-6.78μg/L), and V (2.94-5.01μg/L) between the filter sizes or with depth (8cm and 15cm) in the hyporheic zone. The unfiltered hyporheic zone water samples were analyzed after acid digestion to assess the particulate fraction. These results show a decrease in U concentration (153-202μg/L) and an increase in As (33.2-219μg/L) and V (169-1130μg/L) concentrations compared to the filtered waters. Surface water concentrations of U(171-184μg/L) are lower than the filtered hyporheic zone waters while As(1.32-8.68μg/L) and V(1.75-2.38μg/L) are significantly lower than the hyporheic zone waters and particulates combined. Concentrations of As in the sediment core samples are higher in the first 15cm below the water-sediment interface (14.3-3.82μg/L) and decrease (0.382μg/L) with depth. Uranium concentrations are consistent (0.047-0.050μg/L) at all depths. The over all data suggest that U is mobile in the dissolved phase and both As and V are mobile in the particular phase as they travel through the system.

  1. Disturbance and California riparian tree establishment

    NASA Astrophysics Data System (ADS)

    Bendix, J.; Cowell, C. M.

    2010-12-01

    As is the case in many ecosystems, tree establishment in riparian corridors is often episodic, following disturbance events that clear colonization sites. In many riparian settings, flooding is the most obvious, and relevant disturbance agent. However, in Mediterranean-climate regions, fire is an equally important disturbance agent. In California, the frequency and severity of both floods and fire are expected to change with projected climate change, making an understanding of their roles key to understanding future ecological processes in California riparian environments. In this paper, we use tree-ring data from the Transverse Ranges of Southern California to explore the relative importance of fire and flood in the establishment of riparian gallery forest. We examined 42 cores of Alnus rhombifolia, Populus fremontii and Quercus agrifolia from the riparian zone adjacent to Piedra Blanca and Potrero John Creeks in California’s Transverse Ranges, and compared their establishment dates with records of fire and floods, to see how establishment related to disturbance history. Our results show some evidence for major fire having an impact, as all of the largest stems dated to the few years following the 1932 Matilija fire, which had burned all of the sites in our sample. The remainder of the record is less straightforward, although there is an establishment peak in the 1970s, which may be related to a 1975 fire that burned part of the Potrero John watershed. Of note, the establishment chronology shows no relationship to the flood record, as years of major floods do not relate to either prolific or sparse years in the tree-ring record. This record suggests that large fires may serve as a trigger for tree establishment in California riparian settings, but that they are hardly a prerequisite, as many stems germinated between fires. Indeed, ongoing regeneration is apparently independent of disturbance, given the apparent irrelevance of flooding in this regard. The result

  2. Meta-analysis of nitrogen removal in riparian buffers.

    PubMed

    Mayer, Paul M; Reynolds, Steven K; McCutchen, Marshall D; Canfield, Timothy J

    2007-01-01

    Riparian buffers, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and reducing nitrogen loads entering water bodies. Riparian buffer width is thought to be positively related to nitrogen removal effectiveness by influencing nitrogen retention or removal. We surveyed the scientific literature containing data on riparian buffers and nitrogen concentration in streams and groundwater to identify trends between nitrogen removal effectiveness and buffer width, hydrological flow path, and vegetative cover. Nitrogen removal effectiveness varied widely. Wide buffers (>50 m) more consistently removed significant portions of nitrogen entering a riparian zone than narrow buffers (0-25 m). Buffers of various vegetation types were equally effective at removing nitrogen but buffers composed of herbaceous and forest/herbaceous vegetation were more effective when wider. Subsurface removal of nitrogen was efficient, but did not appear to be related to buffer width, while surface removal of nitrogen was partly related to buffer width. The mass of nitrate nitrogen removed per unit length of buffer did not differ by buffer width, flow path, or buffer vegetation type. Our meta-analysis suggests that buffer width is an important consideration in managing nitrogen in watersheds. However, the inconsistent effects of buffer width and vegetation on nitrogen removal suggest that soil type, subsurface hydrology (e.g., soil saturation, groundwater flow paths), and subsurface biogeochemistry (organic carbon supply, nitrate inputs) also are important factors governing nitrogen removal in buffers.

  3. Gravity anomaly and crustal density structure in Jilantai rift zone and its adjacent region

    NASA Astrophysics Data System (ADS)

    Wu, Guiju; Shen, Chongyang; Tan, Hongbo; Yang, Guangliang

    2016-08-01

    This paper deals with the interpretation of Bouguer gravity anomalies measured along a 250 km long Suhaitu-Etuokeqi gravity profile located at the transitional zone of the Alxa and Ordos blocks where geophysical characteristics are very complex. The analysis is carried out in terms of the ratio of elevation and Bouguer gravity anomaly, the normalized full gradient of a section of the Bouguer gravity anomaly ( G h ) and the crustal density structure reveal that (1) the ratio of highs and lows of elevation and Bouguer gravity anomaly is large between Zhengyiguan fault (F4) and Helandonglu fault (F6), which can be explained due to crustal inhomogeneities related to the uplift of the Qinghai-Tibet block in the northeast; (2) the main active faults correspond to the G h contour strip or cut the local region, and generally show strong deformation characteristics, for example the Bayanwulashan mountain front fault ( F1) or the southeast boundary of Alxa block is in accord with the western change belt of G h , a belt about 10 km wide that extends to about 30 km; (3) Yinchuan-Pingluo fault ( F8) is the seismogenic structure of the Pingluo M earthquake, and its focal depth is about 15 km; (4) the Moho depth trend and Bouguer gravity anomaly variation indicates that the regional gravity field is strongly correlated with the Moho discontinuity.

  4. Gravity anomaly and crustal density structure in Jilantai rift zone and its adjacent region

    NASA Astrophysics Data System (ADS)

    Wu, Guiju; Shen, Chongyang; Tan, Hongbo; Yang, Guangliang

    2016-08-01

    This paper deals with the interpretation of Bouguer gravity anomalies measured along a 250 km long Suhaitu-Etuokeqi gravity profile located at the transitional zone of the Alxa and Ordos blocks where geophysical characteristics are very complex. The analysis is carried out in terms of the ratio of elevation and Bouguer gravity anomaly, the normalized full gradient of a section of the Bouguer gravity anomaly (G h ) and the crustal density structure reveal that (1) the ratio of highs and lows of elevation and Bouguer gravity anomaly is large between Zhengyiguan fault (F4) and Helandonglu fault (F6), which can be explained due to crustal inhomogeneities related to the uplift of the Qinghai-Tibet block in the northeast; (2) the main active faults correspond to the G h contour strip or cut the local region, and generally show strong deformation characteristics, for example the Bayanwulashan mountain front fault (F1) or the southeast boundary of Alxa block is in accord with the western change belt of G h , a belt about 10 km wide that extends to about 30 km; (3) Yinchuan-Pingluo fault (F8) is the seismogenic structure of the Pingluo M earthquake, and its focal depth is about 15 km; (4) the Moho depth trend and Bouguer gravity anomaly variation indicates that the regional gravity field is strongly correlated with the Moho discontinuity.

  5. Timing and causes of gully erosion in the riparian zone of the semi-arid tropical Victoria River, Australia: Management implications

    NASA Astrophysics Data System (ADS)

    McCloskey, G. L.; Wasson, R. J.; Boggs, G. S.; Douglas, M.

    2016-08-01

    Gully erosion in the seasonally wet tropics of Australia is a major source of sediment in rivers. Stabilization of gullies to reduce impacts on aquatic ecosystems and water storages is a focus for management. However, the cause of the gully erosion is poorly understood and so a critical context for soil conservation is missing. It is uncertain if they are the result of post-European cattle grazing or are they much older and related to non-human factors. The causes of riparian gully erosion along a reach of the Victoria River in the semi-arid tropics of Australia were investigated using several methods. Gully complexes were described and characterised by two major components: a Flood Drainage Channel (FDC) and upslope of this an Outer Erosion Feature (OEF) characterised by badlands set within an amphitheatre. The OEF is likely to be a major source of sediment that appears to be of recent origin. A review of historical records, combined with Optically Stimulated Luminescence (OSL) dating, showed that the FDCs were well established prior to the introduction of domestic stock. It also showed that the badlands began to develop about 90 years ago; that is, about 40 years after the arrival of domestic stock. In addition, an analysis of aerial photos coupled with an on-ground survey and analysis of fallout radionuclides revealed that erosion processes are still active within the gully complexes. While the FDCs are natural drainage channels, cattle grazing probably triggered the badland formation, with the expansion aided by increased rainfall in the past 40 years. Therefore, the OEFs are of human origin and protection from grazing of the riparian zone should slow badland erosion and reduce sediment input to the river.

  6. Effect of emergent aquatic insects on bat foraging in a riparian forest.

    PubMed

    Fukui, Dai; Murakami, Masashi; Nakano, Shigeru; Aoi, Toshiki

    2006-11-01

    1. Riparian zones serve several ecological functions for bats. They provide a source of prey and likely provide favourable structural habitats and shelter from predators. Many studies have shown that bats use the space above streams, ponds or riparian vegetation as feeding habitat. These studies, however, have never distinguished between the effects of habitat structure and prey availability on the foraging activities of bats. Such effects can only be distinguished by an experimental approach. We predicted that bat activity along a stream is influenced by the number of emerged aquatic insects. 2. We evaluated the response of terrestrial consumers, insectivorous bats, to changes in the abundance of emergent aquatic insects by conducting a manipulative field experiment. In a deciduous riparian forest in Japan, aquatic insect flux from the stream to the riparian zone was controlled with an insect-proof cover over a 1.2 km stream reach. 3. We estimated the abundance of emergent aquatic and flying terrestrial arthropods near the treatment and control reaches using Malaise traps. The foraging activity of bats was evaluated in both treatment and control reaches using ultrasonic detectors. 4. The insect-proof cover effectively reduced the flux of emergent aquatic insects to the riparian zone adjacent to the treatment reach. Adjacent to the control reach, adult aquatic insect biomass was highest in spring, and then decreased gradually. Terrestrial insect biomass increased gradually during the summer at both treatment and control reaches. 5. Foraging activity of bats was correlated with insect abundance. In spring, foraging activity of bats at the control reach was significantly greater than at the treatment reach, and increased at both sites with increasing terrestrial insect abundance. 6. Our result suggests that the flux of aquatic insects emerging from streams is one of the most important factors affecting the distribution of riparian-foraging bats. As is the case with

  7. Effect of emergent aquatic insects on bat foraging in a riparian forest.

    PubMed

    Fukui, Dai; Murakami, Masashi; Nakano, Shigeru; Aoi, Toshiki

    2006-11-01

    1. Riparian zones serve several ecological functions for bats. They provide a source of prey and likely provide favourable structural habitats and shelter from predators. Many studies have shown that bats use the space above streams, ponds or riparian vegetation as feeding habitat. These studies, however, have never distinguished between the effects of habitat structure and prey availability on the foraging activities of bats. Such effects can only be distinguished by an experimental approach. We predicted that bat activity along a stream is influenced by the number of emerged aquatic insects. 2. We evaluated the response of terrestrial consumers, insectivorous bats, to changes in the abundance of emergent aquatic insects by conducting a manipulative field experiment. In a deciduous riparian forest in Japan, aquatic insect flux from the stream to the riparian zone was controlled with an insect-proof cover over a 1.2 km stream reach. 3. We estimated the abundance of emergent aquatic and flying terrestrial arthropods near the treatment and control reaches using Malaise traps. The foraging activity of bats was evaluated in both treatment and control reaches using ultrasonic detectors. 4. The insect-proof cover effectively reduced the flux of emergent aquatic insects to the riparian zone adjacent to the treatment reach. Adjacent to the control reach, adult aquatic insect biomass was highest in spring, and then decreased gradually. Terrestrial insect biomass increased gradually during the summer at both treatment and control reaches. 5. Foraging activity of bats was correlated with insect abundance. In spring, foraging activity of bats at the control reach was significantly greater than at the treatment reach, and increased at both sites with increasing terrestrial insect abundance. 6. Our result suggests that the flux of aquatic insects emerging from streams is one of the most important factors affecting the distribution of riparian-foraging bats. As is the case with

  8. A Discrete Transition Zone Organizes the Topological and Regulatory Autonomy of the Adjacent Tfap2c and Bmp7 Genes

    PubMed Central

    Tsujimura, Taro; Klein, Felix A.; Langenfeld, Katja; Glaser, Juliane; Huber, Wolfgang; Spitz, François

    2015-01-01

    Despite the well-documented role of remote enhancers in controlling developmental gene expression, the mechanisms that allocate enhancers to genes are poorly characterized. Here, we investigate the cis-regulatory organization of the locus containing the Tfap2c and Bmp7 genes in vivo, using a series of engineered chromosomal rearrangements. While these genes lie adjacent to one another, we demonstrate that they are independently regulated by distinct sets of enhancers, which in turn define non-overlapping regulatory domains. Chromosome conformation capture experiments reveal a corresponding partition of the locus in two distinct structural entities, demarcated by a discrete transition zone. The impact of engineered chromosomal rearrangements on the topology of the locus and the resultant gene expression changes indicate that this transition zone functionally organizes the structural partition of the locus, thereby defining enhancer-target gene allocation. This partition is, however, not absolute: we show that it allows competing interactions across it that may be non-productive for the competing gene, but modulate expression of the competed one. Altogether, these data highlight the prime role of the topological organization of the genome in long-distance regulation of gene expression. PMID:25569170

  9. Adjacent positioning of cellular structures enabled by a Cdc42 GTPase-activating protein-mediated zone of inhibition.

    PubMed

    Tong, Zongtian; Gao, Xiang-Dong; Howell, Audrey S; Bose, Indrani; Lew, Daniel J; Bi, Erfei

    2007-12-31

    Cells of the budding yeast Saccharomyces cerevisiae are born carrying localized transmembrane landmark proteins that guide the subsequent establishment of a polarity axis and hence polarized growth to form a bud in the next cell cycle. In haploid cells, the relevant landmark proteins are concentrated at the site of the preceding cell division, to which they recruit Cdc24, the guanine nucleotide exchange factor for the conserved polarity regulator Cdc42. However, instead of polarizing at the division site, the new polarity axis is directed next to but not overlapping that site. Here, we show that the Cdc42 guanosine triphosphatase-activating protein (GAP) Rga1 establishes an exclusion zone at the division site that blocks subsequent polarization within that site. In the absence of localized Rga1 GAP activity, new buds do in fact form within the old division site. Thus, Cdc42 activators and GAPs establish concentric zones of action such that polarization is directed to occur adjacent to but not within the previous cell division site.

  10. Mulberry trees conserved soil and protected water quality in the riparian zone of the Three Gorges Reservoir, China.

    PubMed

    Liu, Yun; Willison, J H Martin; Wan, Pan; Xiong, Xing-Zheng; Ou, Yang; Huang, Xiao-Hui; Wu, Jingchun; Zhou, Hao; Xu, Qiao; Chen, Guohui; Xili, Yuanzi; Nie, Jiasheng

    2016-03-01

    China's Sloping Land Conversion Program (SLCP) was designed to restore perennial plant cover on sloping land in western China, in part to protect the Three Gorges Reservoir (TGR). In this study, we examined use of white mulberry (Morus alba L.) in the SLCP to protect water quality and conserve soil. We established nine runoff monitoring plots divided among three categories (vegetable farming, fallow control, and mulberry plantation) on a bank of the Liangtan River situated at the western margin of the TGR. The land had been used previously by farmers for growing vegetables. We found that soil loss and surface water runoff were lowest in the mulberry plots and highest in the vegetable plots. We used inductively coupled plasma atomic emission spectroscopy (ICP-AES) to assess the concentration of selected heavy metal pollution indicators (Zn, Hg, As, Ni, Pb, Cr, Cd, and Cu) in the monitoring plot soils at the beginning of the experiment in May 2009. The heavy metals were assessed again at the end of the experiment in October 2012, and we found that the concentrations of these pollutants had been reduced in all fallow and mulberry plots, and to the greatest extent in the mulberry plots. We found that levels of Hg, Pb, and Cu increased in the vegetable plots. For these reasons, we conclude that riparian mulberry plantations are useful for reducing rapid runoff of storm water, conserving soil, and sequestering heavy metal pollutants in the TGR region. PMID:26564183

  11. Mulberry trees conserved soil and protected water quality in the riparian zone of the Three Gorges Reservoir, China.

    PubMed

    Liu, Yun; Willison, J H Martin; Wan, Pan; Xiong, Xing-Zheng; Ou, Yang; Huang, Xiao-Hui; Wu, Jingchun; Zhou, Hao; Xu, Qiao; Chen, Guohui; Xili, Yuanzi; Nie, Jiasheng

    2016-03-01

    China's Sloping Land Conversion Program (SLCP) was designed to restore perennial plant cover on sloping land in western China, in part to protect the Three Gorges Reservoir (TGR). In this study, we examined use of white mulberry (Morus alba L.) in the SLCP to protect water quality and conserve soil. We established nine runoff monitoring plots divided among three categories (vegetable farming, fallow control, and mulberry plantation) on a bank of the Liangtan River situated at the western margin of the TGR. The land had been used previously by farmers for growing vegetables. We found that soil loss and surface water runoff were lowest in the mulberry plots and highest in the vegetable plots. We used inductively coupled plasma atomic emission spectroscopy (ICP-AES) to assess the concentration of selected heavy metal pollution indicators (Zn, Hg, As, Ni, Pb, Cr, Cd, and Cu) in the monitoring plot soils at the beginning of the experiment in May 2009. The heavy metals were assessed again at the end of the experiment in October 2012, and we found that the concentrations of these pollutants had been reduced in all fallow and mulberry plots, and to the greatest extent in the mulberry plots. We found that levels of Hg, Pb, and Cu increased in the vegetable plots. For these reasons, we conclude that riparian mulberry plantations are useful for reducing rapid runoff of storm water, conserving soil, and sequestering heavy metal pollutants in the TGR region.

  12. 100-N Area Strontium-90 Treatability Demonstration Project: Food Chain Transfer Studies for Phytoremediation Along the 100-N Columbia River Riparian Zone

    SciTech Connect

    Fellows, Robert J.; Fruchter, Jonathan S.; Driver, Crystal J.

    2009-04-01

    Strontium-90 (90Sr) exceeds the U.S. Environmental Protection Agency’s drinking water standards for groundwater (8 picocuries/L) by as much as a factor of 1000 at several locations within the Hanford 100-N Area and along the 100-N Area Columbia River shoreline). Phytoextraction, a managed remediation technology in which plants or integrated plant/rhizosphere systems are employed to phytoextract and/or sequester 90Sr, is being considered as a potential remediation system along the riparian zone of the Columbia River as part of a treatment train that includes an apatite barrier to immobilize groundwater transport of 90Sr. Phytoextraction would employ coyote willow (Salix exigua) to extract 90Sr from the vadose zone soil and aquifer sediments (phytoextraction) and filter 90Sr (rhizofiltration) from the shallow groundwater along the riparian zone of the Columbia River. The stem and foliage of coyote willows accumulating 90Sr may present not only a mechanism to remove the contaminant but also can be viewed as a source of nutrition for natural herbivores, therefore becoming a potential pathway for the isotope to enter the riparian food chain. Engineered barriers such as large and small animal fencing constructed around the field plot will control the intrusion of deer, rodents, birds, and humans. These efforts, however, will have limited effect on mobile phytophagous insects. Therefore, this study was undertaken to determine the potential for food chain transfer by insects prior to placement of the remediation technology at 100-N. Insect types include direct consumers of the sap or liquid content of the plants vascular system (xylem and phloem) by aphids as well as those that would directly consume the plant foliage such as the larvae (caterpillars) of Lepidoptera species. Heavy infestations of aphids feeding on the stems and leaves of willows growing in 90Sr-contaminated soil can accumulate a small amount (~0.15 ± 0.06%) of the total label removed from the soil by

  13. 100-N Area Strontium-90 Treatability Demonstration Project: Phytoextraction Along the 100-N Columbia River Riparian Zone – Field Treatability Study

    SciTech Connect

    Fellows, Robert J.; Fruchter, Jonathan S.; Driver, Crystal J.; Ainsworth, Calvin C.

    2010-01-11

    Strontium-90 (90Sr) is present both in the aquifer near the river and in the vadose and riparian zones of the river’s shore at 100-NR-2. Phytoextraction of 90Sr is being considered as a potential remediation system along the riparian zone of the Columbia River. Phytoextraction would employ coyote willow (Salix exigua). Past studies have shown that willow roots share uptake mechanisms for Sr with Ca, a plant macronutrient as well as no discrimination between Sr and 90Sr. Willow 90Sr concentration ratios [CR’s; (pCi 90Sr/g dry wt. of new growth tissue)/(pCi 90Sr/g soil porewater)] were consistently greater than 65 with three-quarters of the assimilated label partitioned into the above ground shoot. Insect herbivore experiments also demonstrated no significant potential for bioaccumulation or food chain transfer from their natural activities. The objectives of this field study were three-fold: (1) to demonstrate that a viable, “managed” plot of coyote willows can be established on the shoreline of the Columbia River that would survive the same microenvironment to be encountered at the 100-NR-2 shoreline; (2) to show through engineered barriers that large and small animal herbivores can be prevented from feeding on these plants; and (3) to show that once established, the plants will provide sufficient biomass annually to support the phytoextraction technology. A field treatability demonstration plot was established on the Columbia River shoreline alongside the 100-K West water intake at the end of January 2007. The plot was delimited by a 3.05 m high chain-link fence and was approximately 10 x 25 m in size. A layer of fine mesh metal small animal screening was placed around the plot at the base of the fencing to a depth of 45 cm. A total of sixty plants were placed in six slightly staggered rows with 1-m spacing between plants. The actual plot size was 0.00461 hectare (ha). At the time of planting (March 12, 2007), the plot was located about 10 m from the

  14. Does the invasive plant, Impatiens glandulifera promote soil erosion from riparian zones? An investigation on a small watercourse in northwest Switzerland

    NASA Astrophysics Data System (ADS)

    Greenwood, Philip; Kuhn, Nikolaus

    2013-04-01

    Impatiens glandulifera (common English name: Himalayan Balsam) was introduced into Europe in the mid-19th century, whereupon its invasive tendency has facilitated its expansion throughout many mainland European countries. Its rate of expansion can be attributed to certain lifecycle traits that allow it to become rapidly established and crowd-out many native floral species. Its preferred habitat includes damp, nutrient-rich soils that experience frequent natural disturbance, such as along riparian zones. Once present, nearby watercourses then inadvertently act as conduits that facilitate the movement of seeds downstream into un-colonised parts of a catchment. Once established, individual plants form discrete and often mono-cultural stands of dense vegetation that can typically range in area from a few m-2 to > 150 m-2. Impatiens glandulifera is cold-intolerant however, and in temperate countries rapidly dies when exposed to the first frosts of the season. Once die-back occurs, it is hypothesised that a reduction in the protection afforded to the underlying soil by the vegetation canopy will promote the mobilisation of material from areas contaminated with I. glandulifera at a greater rate that areas supporting indigeneous vgetation, due to their increased exposure to erosion processes. An investigation was conducted to test this hypothesis in a contaminated sub-catchment of the Birs River in northwest Switzerland. A measurement technique consisting of erosion pins, an erosion bridge and a digital caliper was employed to quantify changes in the soil profile, as this approach represented the least invasive way of repeatedly measuring through vegetation without undue disturbance. An initial soil surface profile was established at five contaminated sites in late summer 2012 before die-back occurred, as well as at five nearby reference sites where I. glandulifera was absent. All soil surface profiles were re-measured at ca. 25-day intervals and the average net change was

  15. Carbon dioxide transport across the hillslope-riparian-stream continuum in a boreal headwater catchment

    NASA Astrophysics Data System (ADS)

    Leith, F. I.; Dinsmore, K. J.; Wallin, M. B.; Billett, M. F.; Heal, K. V.; Laudon, H.; Öquist, M. G.; Bishop, K.

    2015-03-01

    Headwater streams export CO2 as lateral downstream export and vertical evasion from the stream surface. CO2 in boreal headwater streams generally originates from adjacent terrestrial areas, so determining the sources and rate of CO2 transport along the hillslope-riparian-stream continuum could improve estimates of CO2 export via the aquatic pathway, especially by quantifying evasion at higher temporal resolutions. Continuous measurements of dissolved CO2 concentrations and water table were made along the hillslope-riparian-stream continuum in the Västrabäcken sub-catchment of the Krycklan catchment, Sweden. Daily water and CO2 export from the hillslope and riparian zone were estimated over one hydrological year (October 2012-September 2013) using a flow-concentration model and compared with measured lateral downstream CO2 export. Total water export over the hydrological year from the hillslope was 230 mm yr-1 compared with 270 mm yr-1 from the riparian zone. This corresponds well (proportional to the relative upslope contributing area) to the annual catchment runoff of 265 mm yr-1. Total CO2 export from the riparian zone to the stream was 3.0 g CO2-C m-2 yr-1. A hotspot for riparian CO2 export was observed at 30-50 cm depth (accounting for 71 % of total riparian export). Seasonal variability was high with export peaks during the spring flood and autumn storm events. Downstream lateral CO2 export (determined from stream water dissolved CO2 concentrations and discharge) was 1.2 g CO2-C m-2 yr-1. Subtracting downstream lateral export from riparian export (3.0 g CO2-C m-2 yr-1) gives 1.8 g CO2-C m-2 yr-1 which can be attributed to evasion losses (accounting for 60 % of export via the aquatic pathway). The results highlight the importance of terrestrial CO2 export, especially from the riparian zone, for determining catchment aquatic CO2 losses and the importance of the CO2 evasion component to carbon export via the aquatic conduit.

  16. Carbon dioxide transport across the hillslope-riparian-stream continuum in a boreal headwater catchment

    NASA Astrophysics Data System (ADS)

    Leith, F. I.; Dinsmore, K. J.; Wallin, M. B.; Billett, M. F.; Heal, K. V.; Laudon, H.; Öquist, M. G.; Bishop, K.

    2014-11-01

    Headwater streams export CO2 as lateral downstream export and vertical evasion from the stream surface. CO2 in boreal headwater streams generally originates from adjacent terrestrial areas, so determining the sources and rate of CO2 transport along the hillslope-riparian-stream continuum could improve estimates of CO2 export via the aquatic pathway, especially by quantifying evasion at higher temporal resolutions. Continuous measurements of dissolved CO2 concentrations and water table were made along the hillslope-riparian-stream continuum in the Västrabäcken sub-catchment of the Krycklan Catchment, Sweden. Daily water and CO2 export from the hillslope and riparian zone were estimated over one hydrological year (October 2012-September 2013) using a flow-concentration model and compared with measured lateral downstream CO2 export. Total water export over the hydrological year from the hillslope was 230 mm yr-1 compared with 270 mm yr-1 from the riparian zone. This corresponds well (proportional to the relative upslope contributing area) to the annual catchment runoff of 265 mm yr-1. Total CO2 export from the riparian zone to the stream was 3.0 g CO2-C m-2 yr-1. A hotspot for riparian CO2 export was observed at 30-50 cm depth (accounting for 71% of total riparian export). Seasonal variability was high with export peaks during the spring flood and autumn storm events. Downtream lateral CO2 export (determined from stream water dissolved CO2 concentrations and discharge) was 1.2 g CO2-C m-2 yr-1. Subtracting downstream lateral export from riparian export (3.0 g CO2-C m-2 yr-1) gives 1.8 g CO2-C m-2 yr-1 which can be attributed to evasion losses (accounting for 60% of export via the aquatic pathway). The results highlight the importance of terrestrial CO2 export, especially from the riparian zone, for determining catchment aquatic CO2 losses and the importance of the CO2 evasion component to carbon export via the aquatic conduit.

  17. The mantle transition zone beneath the Afar Depression and adjacent regions: implications for mantle plumes and hydration

    NASA Astrophysics Data System (ADS)

    Reed, C. A.; Gao, S. S.; Liu, K. H.; Yu, Y.

    2016-06-01

    The Afar Depression and its adjacent areas are underlain by an upper mantle marked by some of the world's largest negative velocity anomalies, which are frequently attributed to the thermal influences of a lower-mantle plume. In spite of numerous studies, however, the existence of a plume beneath the area remains enigmatic, partially due to inadequate quantities of broad-band seismic data and the limited vertical resolution at the mantle transition zone (MTZ) depth of the techniques employed by previous investigations. In this study, we use an unprecedented quantity (over 14 500) of P-to-S receiver functions (RFs) recorded by 139 stations from 12 networks to image the 410 and 660 km discontinuities and map the spatial variation of the thickness of the MTZ. Non-linear stacking of the RFs under a 1-D velocity model shows robust P-to-S conversions from both discontinuities, and their apparent depths indicate the presence of an upper-mantle low-velocity zone beneath the entire study area. The Afar Depression and the northern Main Ethiopian Rift are characterized by an apparent 40-60 km depression of both MTZ discontinuities and a normal MTZ thickness. The simplest and most probable interpretation of these observations is that the apparent depressions are solely caused by velocity perturbations in the upper mantle and not by deeper processes causing temperature or hydration anomalies within the MTZ. Thickening of the MTZ on the order of 15 km beneath the southern Arabian Plate, southern Red Sea and western Gulf of Aden, which comprise the southward extension of the Afro-Arabian Dome, could reflect long-term hydration of the MTZ. A 20 km thinning of the MTZ beneath the western Ethiopian Plateau is observed and interpreted as evidence for a possible mantle plume stem originating from the lower mantle.

  18. The Surf Zone Ichthyoplankton Adjacent to an Intermittently Open Estuary, with Evidence of Recruitment during Marine Overwash Events

    NASA Astrophysics Data System (ADS)

    Cowley, P. D.; Whitfield, A. K.; Bell, K. N. I.

    2001-03-01

    The composition, structure and seasonality of ichthyoplankton in the surf zone adjacent to the mouth of the intermittently open East Kleinemonde Estuary (33°32'S, 27°03'E) were investigated over a period of 2 years. Altogether 451 fishes, representing at least 21 taxa from 14 families, were collected. The assemblage was dominated by postflexion larvae of euryhaline marine species that are dependent on estuaries as nursery areas. The sparid Rhabdosargus holubi was the most abundant taxon and constituted more than 77% of the total catch. A distinct modal size class was identified for R. holubi , while the mean individual size of this and other abundant taxa was comparable to the observed recruitment size range reported from a wide variety of estuarine nursery habitats in southern Africa. Periodic regression analyses revealed significant peaks in abundance of larval R. holubi during late winter (August), at down and dusk, at new and full moon (spring tides), and on the flood stage of the tidal cycle. Evidence for estuarine immigration during marine overwash events (surging rough seas that enter the estuary) is provided by (1) the stranding of postflexion larvae in the region of the closed estuary mouth following these events, and (2) back extrapolation from length modes within the estuary to coincide with such an event. The advantages and disadvantages of such a recruitment strategy are discussed.

  19. Analyzing riparian forest cover changes along the Firniz River in the Mediterranean City of Kahramanmaras in Turkey.

    PubMed

    Akay, Abdullah E; Sivrikaya, Fatih; Gulci, Sercan

    2014-05-01

    Riparian forests adjacent to surface water are important transitional zones which maintain and enrich biodiversity and ensure the sustainability in a forest ecosystem. Also, riparian forests maintain water quality, reduce sediment delivery, enhance habitat areas for aquatic life and wildlife, and provide ecological corridors between the upland and the downstream. However, the riparian ecosystems have been degraded mainly due to human development, forest operations, and agricultural activities. In order to evaluate the impacts of these factors on riparian forests, it is necessary to estimate trends in forest cover changes. This study aims to analyze riparian forest cover changes along the Firniz River located in Mediterranean city of Kahramanmaras in Turkey. Changes in riparian forest cover from 1989 to 2010 have been determined by implementing supervised classification method on a series of Landsat TM imagery of the study area. The results indicated that the classification process applied on 1989 and 2010 images provided overall accuracy of 80.08 and 75 %, respectively. It was found that the most common land use class within the riparian zone was productive forest, followed by degraded forest, agricultural areas, and other land use classes. The results also indicated that the areas of degraded forest and forest openings increased, while productive forest and agricultural areas decreased between the years of 1989 and 2010. The amount of agricultural areas decreased due to the reduction in the population of rural people. According to these results, it can be concluded that special forest management and operation techniques should be implemented to restore the forest ecosystem in riparian areas. PMID:24338054

  20. Pollution status of polycyclic aromatic hydrocarbons in surface sediments from the Yangtze River Estuary and its adjacent coastal zone.

    PubMed

    Wang, Chenglong; Zou, Xinqing; Gao, Jianhua; Zhao, Yifei; Yu, Wenwen; Li, Yali; Song, Qiaochu

    2016-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are mainly produced by incomplete combustion and are used as indicators of anthropogenic activities on the environment. This study analyses the PAHs level in the Yangtze River Estuary (YRE), an important component of Yangtze River and a developed and populated region in China. Surface sediments were collected from 77 sites at the YRE and its adjacent coastal zone (IACZ) for a comprehensive study of PAHs. Kriging interpolation technology and Positive matrix factorization (PMF) model were applied to explore the spatial distribution and sources of PAHs. Concentrations of 16 PAHs (ΣPAHs) varied from 27.2 ng g(-1) to 621.6 ng g(-1) dry weight, with an average value of 158.2 ng g(-1). Spatially, ΣPAHs exhibited wide fluctuation and exhibited an increasing tendency from north to south. In addition, ΣPAHs exhibited a decreasing trend with increasing distance between the estuary and IACZ. The deposition flux of PAHs indicated that more than 107.8 t a(-1) PAHs was deposited in the study area annually. The results of the PMF model revealed that anthropogenic activities were the main sources of PAHs in the study area. Vehicle emissions and marine engines were the most important sources and accounted for 40.9% of the pollution. Coal combustion, petrogenic sources, and wood combustion were other sources that contributed 23.9%, 23.6%, and 11.5%, respectively. The distribution patterns of PAHs in the YRE and IACZ were influenced by many complicated factors such as sediment grain size, hydrodynamics and so on. PMID:27485799

  1. Soil Methane and Carbon Dioxide Fluxes from Cropland and Riparian Buffers in Different Hydrogeomorphic Settings.

    PubMed

    Jacinthe, P A; Vidon, P; Fisher, K; Liu, X; Baker, M E

    2015-07-01

    Riparian buffers contribute to the mitigation of nutrient pollution in agricultural landscapes, but there is concern regarding their potential to be hot spots of greenhouse gas production. This study compared soil CO and CH fluxes in adjacent crop fields and riparian buffers (a flood-prone forest and a flood-protected grassland along an incised channel) and examined the impact of water table depth (WTD) and flood events on the variability of gas fluxes in riparian zones. Results showed significantly ( < 0.001) higher CO emission in riparian areas than in adjoining croplands (6.8 ± 0.6 vs. 3.6 ± 0.5 Mg CO-C ha yr; mean ± SE). Daily flux of CO and soil temperature were significantly related ( < 0.002), with Q values ranging between 1.75 and 2.53. Significant relationships ( < 0.05) were found between CH daily flux and WTD. Flood events resulted in enhanced CH emission (up to +44.5 mg CH-C m d in a swale) under warm soil conditions (>22°C), but the effect of flooding was less pronounced in early spring (emission <1.06 mg CH-C m d), probably due to low soil temperature. Although CH flux direction alternated at all sites, overall the croplands and the flood-affected riparian forest were CH sources, with annual emission averaging +0.04 ± 0.17 and +0.92 ± 1.6 kg CH-C ha, respectively. In the riparian forest, a topographic depression (<8% of the total area) accounted for 78% of the annual CH emission, underscoring the significance of landscape heterogeneity on CH dynamics in riparian buffers. The nonflooded riparian grassland, however, was a net CH sink (-1.08 ± 0.22 kg CH-C ha yr), probably due to the presence of subsurface tile drains and a dredged/incised channel at that study site. Although these hydrological alterations may have contributed to improvement in the CH sink strength of the riparian grassland, this must be weighed against the water quality maintenance functions and other ecological services provided by riparian buffers. PMID:26437089

  2. RESEARCH SHOWS IMPORTANCE OF RIPARIAN BUFFERS FOR AQUATIC HEALTH

    EPA Science Inventory

    Issue: Excess nitrogen from fertilizer, septic tanks, animal feedlots, and runoff from pavement can threaten aquatic ecosystem health. Riparian buffers -- the vegetated region adjacent to streams and wetlands -- are thought to be effective at intercepting and controlling excess ...

  3. Tritium Fluxes through the Shallow Unsaturated Zone adjacent to a Radioactive Waste Disposal Facility in an Arid Environment

    NASA Astrophysics Data System (ADS)

    Maples, S.; Andraski, B. J.; Stonestrom, D. A.; Cooper, C. A.; Pohll, G.

    2011-12-01

    Studies at the U.S. Geological Survey's Amargosa Desert Research Site (ADRS) in southern Nevada have documented long-distance (>400-m) tritium (3H) transport adjacent to a commercial, low-level radioactive waste disposal facility. Transport at this scale is orders of magnitude greater than anticipated; however, lateral 3H fluxes through the shallow unsaturated zone (UZ) have not been investigated in detail. The objective of this study is to estimate and compare lateral and vertical tritiated water-vapor (3HHOg) fluxes in the shallow UZ and their relation to the observed plume migration. Previous studies have recognized two distinct plumes of 3H emanating from the facility. Shallow (0.5 and 1.5-m depth) soil-water vapor samples were collected yearly along 400-m long transects through both plumes from 2003-09. Within the south plume, 3H concentrations at 1.5-m depth have decreased by 44 ± 0.3% during this period, and plume advancement there has effectively ceased (i.e., rate of advance equals rate of decay). During the same period, the west plume showed a net decrease in concentration of 34 ± 0.9% within 100-m of the facility; however, plume advancement is observed at the leading edge of the plume, and concentrations 200-300-m from the facility show an increase in 3H concentration of 64 ± 28.4%. Lateral and vertical diffusive fluxes within both plumes were calculated using 3HHOg concentrations from 2006. Lateral 3HHOg diffusive fluxes within both plumes have been estimated 25-300-m from the facility at 1.5-m depth. Mean lateral 3HHOg diffusive fluxes are 10-14 g m-2 yr-1 within the south plume, and 10-13 g m-2 yr-1 within the west plume. Mean lateral fluxes in the south plume are an order of magnitude lower than in the west plume. This behavior corresponds with the observed relative immobility of the south plume, while the elevated west plume fluxes agree with the plume advancement seen there. Shallow, upward directed, mean vertical 3HHOg fluxes 25-300-m from the

  4. Riparian Wetlands: Mapping

    EPA Science Inventory

    Riparian wetlands are critical systems that perform functions and provide services disproportionate to their extent in the landscape. Mapping wetlands allows for better planning, management, and modeling, but riparian wetlands present several challenges to effective mapping due t...

  5. Modeling The Water Table In The Middle Rio Grande River Riparian Corridor

    NASA Astrophysics Data System (ADS)

    Akasheh, O. Z.; Neale, C. M.

    2007-12-01

    The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. An arid area with low water resources created a situation where water is extensively diverted or stored to supply the high demand for municipalities and agricultural activities. The extensive water diversions over the last few decades has affected the composition of the native riparian vegetation such as cottonwood and coyote willow and enhanced the spread of invasive species harmful to the river system such as Tamarisk and Russian Olives. The river aquatic system has also been badly affected. The need to study the river hydrological processes and their relation with its health is important to preserve the river ecosystem. The water table within the riparian zone is intrinsically connected to the flows in the river. Large withdrawals of water by Tamarisk affect the surface flows, which coupled with the large diversions for irrigation result in a complicated river management problem. In this paper we describe the methodology used to spatially model the water table depth between the river and the adjacent drains parallel to the river. Water table readings are used to check the model. Evapotranspiration by the riparian vegetation is estimated and included in the soil moisture balance. The model runs as an application in ArcGIS. Spatial layers include soils and riparian vegetation maps obtained from the classification of airborne high resolution multispectral imagery.

  6. Riparian evapotranspiration in Nebraska

    USGS Publications Warehouse

    Hall, Brent M.; Rus, David L.

    2013-01-01

    With increasing demands being placed on the water resources of Nebraska, characterizing evapotranspiration (ET) from riparian vegetation has gained importance to water users and managers. This report summarizes and compares the results from several studies of the ET from cottonwood-dominated riparian forests, riparian grasslands, and common reed, Phragmites australis, in Nebraska. Reported results show that the highest seasonal ET amounts were associated with Phragmites australis, followed by riparian forests, with riparian grasslands experiencing the lowest total ET of the studied vegetation communities.

  7. Nitrous oxide emission from riparian buffers in relation to vegetation and flood frequency.

    PubMed

    Jacinthe, P A; Bills, J S; Tedesco, L P; Barr, R C

    2012-01-01

    The nitrate (NO(3)(-)) removal capacity of riparian zones is well documented, but information is lacking with regard to N(2)O emission from riparian ecosystems and factors controlling temporal dynamics of this potent greenhouse gas. We monitored N(2)O fluxes (static chambers) and measured denitrification (C(2)H(2) block using soil cores) at six riparian sites along a fourth-order stretch of the White River (Indiana, USA) to assess the effect of flood regime, vegetation type, and forest maturity on these processes. The study sites included shrub/grass, aggrading (<15 yr-old), and mature (>80 yr) forests that were flooded either frequently (more than four to six times per year), occasionally (two to three times per year), or rarely (every 20 yr). While the effect of forest maturity and vegetation type (0.52 and 0.65 mg N(2)O-m(-2) d(-1) in adjacent grassed and forested sites) was not significant, analysis of variance (ANOVA) revealed a significant effect ( < 0.01) of flood regime on N(2)O emission. Among the mature forests, mean N(2)O flux was in this order: rarely flooded (0.33) < occasionally flooded (0.99) < frequently flooded (1.72). Large pulses of N(2)O emission (up to 80 mg N(2)O-m(-2) d(-1)) occurred after flood events, but the magnitude of the flux enhancement varied with flood event, being higher after short-duration than after long-duration floods. This pattern was consistent with the inverse relationship between soil moisture and mole fraction of N(2)O, and instances of N(2)O uptake near the river margin after flood events. These results highlight the complexity of N(2)O dynamics in riparian zones and suggest that detailed flood analysis (frequency and duration) is required to determine the contribution of riparian ecosystems to regional N(2)O budget.

  8. Legal mechanisms for protecting riparian resource values

    USGS Publications Warehouse

    Lamb, Berton L.; Lord, Eric

    1992-01-01

    Riparian resources include the borders of rivers, lakes, ponds, and potholes. These border areas are very important for a number of reasons, including stream channel maintenance, flood control, aesthetics, erosion control, fish and wildlife habitat, recreation, and water quality maintenance. These diverse functions are not well protected by law or policy. We reviewed law and policies regarding endangered species habitat designation, land use planning, grazing management, water allocation, takings, and federal permits and licenses, along with the roles of federal, state, and local governments. We discuss the politics of implementing these policies, focusing on the difficulties in changing entrenched water and land use practices. Our review indicates a lack of direct attention to riparian ecosystem issues in almost all environmental and land use programs at every level of government. Protection of riparian resource values requires a means to integrate existing programs to focus on riparian zones.

  9. Clinical evaluation of expanded mesh connective tissue graft in the treatment for multiple adjacent gingival recessions in the esthetic zone

    PubMed Central

    Shanmugam, M.; Shivakumar, B.; Meenapriya, B.; Anitha, V.; Ashwath, B.

    2015-01-01

    Background: Multiple approaches have been used to replace lost, damaged or diseased gingival tissues. The connective tissue graft (CTG) procedure is the golden standard method for root coverage. Although multiple sites often need grafting, the palatal mucosa supplies only a limited area of grafting material. To overcome this limitation, expanded mesh graft provides a method whereby a graft can be stretched to cover a large area. The aim of this study was to evaluate the effectiveness and the predictability of expanded mesh CTG (e-MCTG) in the treatment of adjacent multiple gingival recessions. Materials and Methods: Sixteen patients aged 20–50 years contributed to 55 sites, each site falling into at least three adjacent Miller's Class 1 or Class 2 gingival recession. The CTG obtained from the palatal mucosa was expanded to cover the recipient bed, which was 1.5 times larger than the graft. Clinical measurements were recorded at baseline and 3 months, 12 months postoperatively. Results: A mean coverage of 1.96 mm ± 0.66 mm and 2.22 mm ± 0.68 mm was obtained at the end of 3rd and 12th month, respectively. Twelve months after surgery a statistically significant increase in CAL (2.2 mm ± 0.68 mm, P < 0.001) and increasing WKT (1.75 ± 0.78, P < 0.001) were obtained. In 80% of the treated sites, 100% root coverage was achieved (mean 93.5%). Conclusions: The results of this study demonstrated that multiple adjacent recessions were treated by using e-MCTG technique can be applied and highly predictable root coverage can be achieved. PMID:26321829

  10. Riparian Ficus Tree Communities: The Distribution and Abundance of Riparian Fig Trees in Northern Thailand

    PubMed Central

    Pothasin, Pornwiwan; Compton, Stephen G.; Wangpakapattanawong, Prasit

    2014-01-01

    Fig trees (Ficus) are often ecologically significant keystone species because they sustain populations of the many seed-dispersing animals that feed on their fruits. They are prominent components of riparian zones where they may also contribute to bank stability as well as supporting associated animals. The diversity and distributions of riparian fig trees in deciduous and evergreen forests in Chiang Mai Province, Northern Thailand were investigated in 2010–2012. To record the diversity and abundance of riparian fig trees, we (1) calculated stem density, species richness, and diversity indices in 20×50 m randomly selected quadrats along four streams and (2) measured the distances of individual trees from four streams to determine if species exhibit distinct distribution patterns within riparian zones. A total of 1169 individuals (from c. 4 ha) were recorded in the quadrats, representing 33 Ficus species (13 monoecious and 20 dioecious) from six sub-genera and about 70% of all the species recorded from northern Thailand. All 33 species had at least some stems in close proximity to the streams, but they varied in their typical proximity, with F. squamosa Roxb. and F. ischnopoda Miq the most strictly stream-side species. The riparian forests in Northern Thailand support a rich diversity and high density of Ficus species and our results emphasise the importance of fig tree within the broader priorities of riparian area conservation. Plans to maintain or restore properly functioning riparian forests need to take into account their significance. PMID:25310189

  11. Riparian Ficus tree communities: the distribution and abundance of riparian fig trees in northern Thailand.

    PubMed

    Pothasin, Pornwiwan; Compton, Stephen G; Wangpakapattanawong, Prasit

    2014-01-01

    Fig trees (Ficus) are often ecologically significant keystone species because they sustain populations of the many seed-dispersing animals that feed on their fruits. They are prominent components of riparian zones where they may also contribute to bank stability as well as supporting associated animals. The diversity and distributions of riparian fig trees in deciduous and evergreen forests in Chiang Mai Province, Northern Thailand were investigated in 2010-2012. To record the diversity and abundance of riparian fig trees, we (1) calculated stem density, species richness, and diversity indices in 20×50 m randomly selected quadrats along four streams and (2) measured the distances of individual trees from four streams to determine if species exhibit distinct distribution patterns within riparian zones. A total of 1169 individuals (from c. 4 ha) were recorded in the quadrats, representing 33 Ficus species (13 monoecious and 20 dioecious) from six sub-genera and about 70% of all the species recorded from northern Thailand. All 33 species had at least some stems in close proximity to the streams, but they varied in their typical proximity, with F. squamosa Roxb. and F. ischnopoda Miq the most strictly stream-side species. The riparian forests in Northern Thailand support a rich diversity and high density of Ficus species and our results emphasise the importance of fig tree within the broader priorities of riparian area conservation. Plans to maintain or restore properly functioning riparian forests need to take into account their significance.

  12. Riparian habitat on the Humboldt River, Deeth to Elko, Nevada

    NASA Technical Reports Server (NTRS)

    Price, K. P.; Ridd, M. K.

    1983-01-01

    A map inventory of the major habitat types existing along the Humbolt River riparian zone in Nevada is described. Through aerialphotography, 16 riparian habitats are mapped that describe the ecological relationships between soil and vegetation types, flooding and soil erosion, and the various management practices employed to date. The specific land and water management techniques and their impact on the environment are considered.

  13. Metamorphic conditions in the Nilgiri Granulite Terrane and the adjacent Moyar and Bhavani Shear Zones: A reevaluation

    NASA Technical Reports Server (NTRS)

    Raith, M.; Hengst, C.; Nagel, B.; Bhattacharya, A.; Srikantappa, C.

    1988-01-01

    Data were presented on pressure and temperature determinations from the Nilgiri Hills. About 70 samples were analyzed by probe and several calibrations of garnet-pyroxene thermometry and barometry applied. Most calibrations gave considerable scatter; however, a new calibration by Bhattacharya, Raith, Lal, and others, accounting for nonideality in both garnet and orthopyroxene, gave consistent results of 754 + or - 52 C and 9.2 + or - 0.7 kbar. On the regional scale, a pressure increase of 6.5 to 7 kbar in the SW to 11 kbar in the NE was related to block tilting. A continuous pressure gradient into the Moyar shear zone suggests that the zone is not a suture juxtaposing unrelated blocks.

  14. Reach-Scale Influence of Riparian Vegetation on Fluvial Erosion (Invited)

    NASA Astrophysics Data System (ADS)

    Wynn, T.; Hopkinson, L. C.

    2009-12-01

    A strong link exists between riparian vegetation and stream channel morphology. With increased emphasis on water quality and aquatic habitat in headwater streams, a complete understanding of the role of riparian vegetation on channel form is important for effective stream management and restoration. Streambank fluvial erosion plays a key role in channel migration; streambank undercutting leads to slope instability, mass wasting, and bank retreat. By influencing the local microclimate, streambank hydrology and soil strength, and reach-scale hydraulics, riparian vegetation exerts considerable influence on the processes involved in channel form. The susceptibility of streambank soils to fluvial entrainment depends not only on the soil type, but also on soil moisture, bulk density, and the soil stress history due to wet/dry and freeze/thaw cycling. Riparian vegetation exerts significant influence on all of these factors through precipitation interception, increased infiltration and evapotranspiration, and altered exposure to day time solar heating and night time cooling. The timing and magnitude of these influences depends on the vegetation form, root distribution, and temporal growth patterns. Riparian vegetation also increases the physical resistance of streambank soils to hydraulic shear stress through root reinforcement; the roots of herbaceous plants are typically very fine and are located primarily within the top 30 cm of the soil. In comparison, woody plants have a more uniform root distribution over the upper 1 m of the streambank, providing root reinforcement with greater depth. The presence of above-ground vegetation on streambanks increases hydraulic resistance and alters both flow and turbulence patterns in the channel. Dense riparian vegetation creates a zone of uniform velocity adjacent to the streambank, with an additional boundary layer and area of increased turbulence at the interface between the vegetation and the main channel. At high flows, flexible

  15. Records of bulk organic matter and plant pigments in sediment of the "red-tide zone" adjacent to the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Kang, Zhenjun; Yu, Rencheng; Kong, Fanzhou; Wang, Yunfeng; Gao, Yan; Chen, Jianhua; Guo, Wei; Zhou, Mingjiang

    2016-09-01

    Cultural eutrophication caused by nutrient over-enrichment in coastal waters will lead to a cascading set of ecosystem changes and deleterious ecological consequences, such as harmful algal blooms (HABs) and hypoxia. During the past two decades since the late 1990s, recurrent large-scale HABs (red tides) and an extensive hypoxic zone have been reported in the coastal waters adjacent to the Changjiang River estuary. To retrieve the history of eutrophication and its associated ecosystem changes, a sediment core was collected from the "red-tide zone" adjacent to the Changjiang River estuary. The core was dated using the 210Pb radioisotope and examined for multiple proxies, including organic carbon (OC), total nitrogen (TN), stable isotopes of C and N, and plant pigments. An apparent up-core increase of OC content was observed after the 1970s, accompanied by a rapid increase of TN. The concurrent enrichment of δ13C and increase of the C/N ratio suggested the accumulation of organic matter derived from marine primary production during this stage. The accumulation of OC after the 1970s well reflected the significant increase of primary production in the red-tide zone and probably the intensification of hypoxia as well. Plant pigments, including chlorophyll a, β-carotene, and diatoxanthin, showed similar patterns of variation to OC throughout the core, which further confirmed the important contribution of microalgae, particularly diatoms, to the deposited organic matter. Based on the variant profiles of the pigments representative of different microalgal groups, the potential changes of the phytoplankton community since the 1970s were discussed.

  16. Mapping the response of riparian vegetation to possible flow reductions in the Snake River, Idaho

    NASA Astrophysics Data System (ADS)

    Carter Johnson, W.; Dixon, Mark D.; Simons, Robert; Jenson, Susan; Larson, Kevin

    1995-09-01

    This study was initiated to determine the general effects of potential flow reductions in the middle Snake River (Swan Falls Dam downstream to the Idaho-Oregon border) on its riparian vegetation. Considerable water from the river is currently used to irrigate the adjacent Snake River Plain, and increased demand for water in the future is likely. The problem was subdivided into several research components including: field investigation of the existing riparian vegetation and river environment, hydrological modeling to calculate the effects of one flow scenario on hydrological regime, and integration of vegetation and hydrological modeling results with a Geographic Information System (GIs) to map the riverbed, island, and bank conditions under the scenario flow. Field work was conducted in summer 1990. Riparian vegetation along 40 U.S. Geological Survey cross-sections was sampled at approximately 1.25 mile intervals within the 50 mile long study area. Cross-section and flow data were provided by the U.S. Geological. Survey. GIs mapping of land/water cover using ARC/INFO was based on 1987 aerial photographs. Riverbed contour maps were produced by linking cross-section data, topographic contouring software ( ANUDEM), and GIs. The maps were used to spatially display shallow areas in the channel likely to become vegetated under reduced flow conditions. The scenario would reduce flow by approximately 20% (160 MAF) and lower the river an average of 0.5 ft. The scenario flow could cause a drop in the elevation of the riparian zone comparable to the drop in mean river level and expansion of the lower riparian zone into shallow areas of the channel. The GIs maps showed that the shallow areas of the channel more likely to become vegetated under the scenario flow are located in wide reaches near islands. Some possible ecological consequences of the scenario flow include a greater area of riparian habitat, reduced flow velocity and sedimentation in shallow channels leading to

  17. GLORIA sidescan-sonar imagery for parts of the U.S. Exclusive Economic Zone and adjacent areas

    USGS Publications Warehouse

    Paskevich, Valerie F.; Wong, Florence L.; O'Malley, John J.; Stevenson, Andrew J.; Gutmacher, Christina E.

    2011-01-01

    In 1983, President Ronald Reagan signed a Proclamation establishing the Exclusive Economic Zone (EEZ) of the United States extending its territory 200 nautical miles from the coasts of the United States, Puerto Rico, the Northern Mariana Islands, and other U.S. territories and possessions. The charter of the U.S. Geological Survey (USGS) places the primary responsibility for mapping the territories of the United States within the USGS. Upon declaration of the EEZ, the territory of the United States was enlarged by more than 13 million square kilometers, all of which are under water. The USGS EEZ-SCAN program to systematically map the EEZ began in 1984 and continued through 1991. This digital publication contains all the GLORIA sidescan imagery of the deep-water (greater than 200 meters) portion of the EEZ mapped during those 8 years of data collection. For each EEZ area, we describe the data collection surveys and provide downloads of the GLORIA data and metadata.

  18. Riparian Vegetation Effects on Near-Bank Turbulence During Overbank Flows: A Flume Experiment

    NASA Astrophysics Data System (ADS)

    McBride, M.; Thompson, D. M.; Owen, T. E.; Pearce, A. R.; Hession, W. C.; Rizzo, D.

    2005-12-01

    Measurements from a fixed-bed, Froude-scaled hydraulic model of a stream in northeastern Vermont demonstrated the importance of riparian vegetation effects on near-bank turbulence during overbank flood events. The prototype stream, a tributary to Sleepers River, increased in channel width within the last 40 years in response to passive reforestation of its riparian zone. Previous research has found that reaches of small streams with forested riparian zones are commonly wider that adjacent reaches with non-forested, or meadow, vegetation; however, the driving mechanisms for this morphologic difference are not fully explained. Flume experiments were performed to investigate near-bank turbulence as a mechanism for channel widening in response to reforestation. A 1:5 scale, simplified model of half a channel and its adjacent floodplain was constructed within a 6 m long recirculating flume. The test region was 3.7 m long and 0.9 m wide and oriented with the channel centerline at the flume wall. The channel bed slope was fixed at 0.03, and experiments were run at three discharges: 30, 33, and 36 l/s. Two types of riparian vegetation scenarios were simulated: forested, with rigid, randomly-distributed, wooden dowels, and non-forested, with synthetic grass carpeting. Three-dimensional velocities were measured with a Nortek Vectrino acoustic Doppler velocimeter at 41 different locations within the channel and floodplain at near-bed and 0.6-depth elevations. Observations of three-dimensional velocities and calculations of turbulent kinetic energy (TKE) showed significant differences between forested and non-forested runs. Results indicated that turbulence intensity, as quantified by TKE, roughly doubled throughout the channel and floodplain when forested vegetation was introduced. Given that sediment entrainment and transport can be amplified in flows with high turbulence intensity, our results demonstrated the potential for increased erosion during overbank flood events in

  19. A rapid method to map the crustal and lithospheric thickness using elevation, geoid anomaly and thermal analysis. Application to the Gibraltar Arc System, Atlas Mountains and adjacent zones

    NASA Astrophysics Data System (ADS)

    Fullea, J.; Fernàndez, M.; Zeyen, H.; Vergés, J.

    2007-02-01

    We present a method based on the combination of elevation and geoid anomaly data together with thermal field to map crustal and lithospheric thickness. The main assumptions are local isostasy and a four-layered model composed of crust, lithospheric mantle, sea water and the asthenosphere. We consider a linear density gradient for the crust and a temperature dependent density for the lithospheric mantle. We perform sensitivity tests to evaluate the effect of the variation of the model parameters and the influence of RMS error of elevation and geoid anomaly databases. The application of this method to the Gibraltar Arc System, Atlas Mountains and adjacent zones reveals the presence of a lithospheric thinning zone, SW-NE oriented. This zone affects the High and Middle Atlas and extends from the Canary Islands to the eastern Alboran Basin and is probably linked with a similarly trending zone of thick lithosphere constituting the western Betics, eastern Rif, Rharb Basin, and Gulf of Cadiz. A number of different, even mutually opposite, geodynamic models have been proposed to explain the origin and evolution of the study area. Our results suggest that a plausible slab-retreating model should incorporate tear and asymmetric roll-back of the subducting slab to fit the present-day observed lithosphere geometry. In this context, the lithospheric thinning would be caused by lateral asthenospheric flow. An alternative mechanism responsible for lithospheric thinning is the presence of a hot magmatic reservoir derived from a deep ancient plume centred in the Canary Island, and extending as far as Central Europe.

  20. Surface water and groundwater nitrogen dynamics in a well drained riparian forest within a poorly drained agricultural landscape.

    PubMed

    Davis, Jennifer H; Griffith, Stephen M; Wigington, Parker J

    2011-01-01

    The effectiveness of riparian zones in mitigating nutrient in ground and surface water depends on the climate, management, and hydrogeomorphology of a site. The purpose of this study was to determine the efficacy of a well drained, mixed-deciduous riparian forest to buffer a river from N originating from a poorly drained grass seed cropping system. The study site was adjacent to the Calapooia River in the Willamette Valley, Oregon. Water was found to move from the rapid drainage of swale surface water. During winter hydrological events, the riparian forest also received river water. Low nitrate (NO3-) concentrations (0.2-0.4 mg NO3- -NL(-1)) in the shallow groundwater of the cropping system were associated with low rates of mineralization and nitrification (33 kg N ha(-1) yr(-1)) and high grass seed crop uptake of N (155 kg N ha(-1) yr(-1)). The riparian forest soil had higher rates of mineralization (117 kg N ha(-1) yr(-1)) that produced quantities of soil N that were within the range of literature values for plant uptake, leading to relatively low concentrations of shallow groundwater NO3 (0.6-1.8 mg NO3- -NL(-1)). The swale that dissected the cropping system and riparian area was found to have the highest rates of denitrification and to contribute dissolved organic C to the river. Given the dynamic nature of the hydrology of the Calapooia River study site, data suggest that the riparian forest plays a role not only in reducing export of NO3- from the cropping system to the river but also in processing nutrients from river water.

  1. Supra-subduction zone extensional magmatism in Vermont and adjacent Quebec: Implications for early Paleozoic Appalachian tectonics

    USGS Publications Warehouse

    Kim, J.; Coish, R.; Evans, M.; Dick, G.

    2003-01-01

    Metadiabasic intrusions of the Mount Norris Intrusive Suite occur in fault-bounded lithotectonic packages containing Stowe, Moretown, and Cram Hill Formation lithologies in the northern Vermont Rowe-Hawley belt, a proposed Ordovician arc-trench gap above an east-dipping subduction zone. Rocks of the Mount Norris Intrusive Suite are characteristically massive and weakly foliated, have chilled margins, contain xenoliths, and have sharp contacts that both crosscut and are parallel to early structural fabrics in the host metasedimentary rocks. Although the mineral assemblage of the Mount Norris Intrusive Suite is albite + actinolite + epidote + chlorite + calcite + quartz, intergrowths of albite + actinolite are probably pseudomorphs after plagioclase + clinopyroxene. The metadiabases are subalkaline, tholeiitic, hypabyssal basalts with preserved ophitic texture. A backarc-basin tectonic setting for the intrusive suite is suggested by its LREE (light rare earth element) enrichment, negative Nb-Ta anomalies, and Ta/Yb vs. Th/Yb trends. Although no direct isotopic age data are available, the intrusions are broadly Ordovician because their contacts are clearly folded by the earliest Acadian (Silurian-Devonian) folds. Field evidence and geochemical data suggest compelling along-strike correlations with the Coburn Hill Volcanics of northern Vermont and the Bolton Igneous Group of southern Quebec. Isotopic and stratigraphic age constraints for the Bolton Igneous Group bracket these backarc magmas to the 477-458 Ma interval. A tectonic model that begins with east-dipping subduction and progresses to outboard west-dipping subduction after a syncollisional polarity reversal best explains the intrusion of deformed metamorphosed metasedimentary rocks by backarc magmas.

  2. Isotopologue ratios of N2O and N2 measurements underpin the importance of denitrification in differently N-loaded riparian alder forests.

    PubMed

    Mander, Ulo; Well, Reinhard; Weymann, Daniel; Soosaar, Kaido; Maddison, Martin; Kanal, Arno; Lõhmus, Krista; Truu, Jaak; Augustin, Jürgen; Tournebize, Julien

    2014-10-21

    Known as biogeochemical hotspots in landscapes, riparian buffer zones exhibit considerable potential concerning mitigation of groundwater contaminants such as nitrate, but may in return enhance the risk for indirect N2O emission. Here we aim to assess and to compare two riparian gray alder forests in terms of gaseous N2O and N2 fluxes and dissolved N2O, N2, and NO3(-) in the near-surface groundwater. We further determine for the first time isotopologue ratios of N2O dissolved in the riparian groundwater in order to support our assumption that it mainly originated from denitrification. The study sites, both situated in Estonia, northeastern Europe, receive contrasting N loads from adjacent uphill arable land. Whereas N2O emissions were rather small at both sites, average gaseous N2-to-N2O ratios inferred from closed-chamber measurements and He-O laboratory incubations were almost four times smaller for the heavily loaded site. In contrast, groundwater parameters were less variable among sites and between landscape positions. Campaign-based average (15)N site preferences of N2O (SP) in riparian groundwater ranged between 11 and 44 ‰. Besides the strong prevalence of N2 emission over N2O fluxes and the correlation pattern between isotopologue and water quality data, this comparatively large range highlights the importance of denitrification and N2O reduction in both riparian gray alder stands. PMID:25264900

  3. Baseline assessment of instream and riparian-zone biological resources on the Rio Grande in and near Big Bend National Park, Texas

    USGS Publications Warehouse

    Moring, James Bruce

    2002-01-01

    Five study sites, and a sampling reach within each site, were established on the Rio Grande in and near Big Bend National Park in 1999 to provide the National Park Service with data and information on the status of stream habitat, fish communities, and benthic macroinvertebrates. Differences in stream-habitat conditions and riparian vegetation reflect differences in surface geology among the five sampling reaches. In the most upstream reach, Colorado Canyon, where igneous rock predominates, streambed material is larger; and riparian vegetation is less diverse and not as dense as in the four other, mostly limestone reaches. Eighteen species of fish and a total of 474 individuals were collected among the five reaches; 348 of the 474 were minnows. The most fish species (15) were collected at the Santa Elena reach and the fewest species (9) at the Colorado Canyon and Johnson Ranch reaches. The fish community at Colorado Canyon was least like the fish communities at the four other reaches. Fish trophic structure reflected fish-community structure among the five reaches. Invertivores made up at least 60 percent of the trophic structure at all reaches except Colorado Canyon. Piscivores dominated the trophic structure at Colorado Canyon. At the four other reaches, piscivores were the smallest trophic group. Eighty percent of the benthic macroinvertebrate taxa collected were aquatic insects. Two species of blackfly were the most frequently collected invertebrate taxon. Net-spinning caddisflies were common at all reaches except Santa Elena. The aquatic-insect community at the Boquillas reach was least similar to the aquatic-insect community at the other reaches.

  4. Simulation of Soil Quality with Riparian Forests and Cultivated with Sugarcane

    NASA Astrophysics Data System (ADS)

    da Silva, Luiz Gabriel; Colato, Alexandre; Casagrande, José Carlos; Soares, Marcio Roberto; Perissatto Meneghin, Silvana

    2013-04-01

    Riparian forests are entrusted with important hydrological functions, such as riparian zone protection, filtering sediments and nutrients and mitigation of the amount of nutrients and xenobiotic molecules from the surrounding agro ecosystems. The soil was sampled in the depths of 0-0,2 and 0.2-0.4 m and its chemical (nutrient content and organic matter, cationic exchange capacity - CEC, sum of bases-SB, bases saturation, V%, and aluminum saturation, m%); physical (particle size distribution, density and porosity) and microbiological attributes (basal respiration and microbial biomass) were determined. This work aimed to study the liner method of combining data, figures of merit (FoM), weighing process and the scoring functions developed by Wymore and asses the quality of the soil (SQI) by means of chemical, physical and microbiological soil attributes, employing the additive pondered model for two areas of riparian forest at different stages of ecological succession and an adjacent area cultivated with sugar cane, located on the dam shores of Sugar Mill Saint Lucia-Araras/SP. Some hierarchical functions containing FoMs and their parameters were constructed, and from them weights were assigned to each FoM and parameter, in a way that cluster of structures with the same FoMs and parameters with different weights were formed. These clusters were used to calculate the SQI for all vegetal formations considering two types of soil (Oxisol and Podzol), in that way, the SQI was calculated for each combination of vegetation and soil. The SQIs values were usually higher in the oldest riparian forest, while the recent riparian forest showed the smallest SQI values, for both types of soil. The variation of values within a combination vegetation/soil was also different between all combinations, being that the set of values from the oldest riparian forest presented the lowest amplitude. It was also observed that the Oxisols, regardless of the vegetation, presented higher SQIs

  5. REMM: The Riparian Ecosystem Management Model

    SciTech Connect

    Lowrance, R.; Altier, L.S.; Williams, R.G.; Inamdar, S.P.; Sheridan, J.M.; Bosch, D.D.; Hubbard, R.K.; Thomas, D.L.

    2000-03-01

    Riparian buffer zones are effective in mitigating nonpoint source pollution and have been recommended as a best management practice (BMP). The Riparian Ecosystem Management Model (REMM) has been developed for researchers and natural resource agencies as a modeling tool that can help quantify the water quality benefits of riparian buffers under varying site conditions. Processes simulated in REMM include surface and subsurface hydrology; sediment transport and deposition; carbon, nitrogen, and phosphorus transport, removal, and cycling; and vegetation growth. Management options, such as vegetation type, size of the buffer zone, and biomass harvesting also can be simulated. REMM can be used in conjunction with upland models, empirical data, or estimated loadings to examine scenarios of buffer zone design for a hillslope. Evaluation of REMM simulations with field observations shows generally good agreement between simulated and observed data for groundwater nitrate concentrations and water table depths in a mature riparian forest buffer. Sensitivity analysis showed that changes that influenced the water balance or soil moisture storage affected the streamflow output. Parameter changes that influence either hydrology or rates of nutrient cycling affected total N transport and plant N uptake.

  6. Riparian vegetation assessment of Cauvery River Basin of South India.

    PubMed

    Sunil, C; Somashekar, R K; Nagaraja, B C

    2010-11-01

    The Cauvery river basin of South India has a large phyto-floristic wealth, rightfully enough to constitute a separate phyto-geographic unit. Increase in the anthropogenic pressures within the river basin and surrounding landscapes have persistently stressed the riparian ecosystem structure adversely, besides altering its composition. The objective of this study was to examine the present status of riparian vegetation along the Cauvery river basin, in response to anthropogenic pressures. For vegetation analysis, the riparian forest coming in the middle stretch of Cauvery river was categorized into two zones, viz., forest zone covering ~54 km stretch and agroecosystem zone covering ~80 km stretch. In each zone, tree species were quantified using transects at 8-km interval. Overall tree species accounting for both forest and agroecosystem were recorded and compared. The results indicate that the mean density and basal area of trees per plot were higher in the forest zone than agroecosystem zone. The Shannon-Weiner diversity of forest zone is 4.6, which is higher than agroecosystem. In addition, species composition indicated a relatively low or poor similarity between the two zones. The vegetation density and site disturbance scores for all the study sites reveals that sand mining and grazing areas have exerted negative impact on riparian forest. The results of the present study clearly brought out the need for preparing and implementing site-specific conservation plans for riparian ecosystem.

  7. Approaches to characterizing biogeochemistry effects of groundwater and surface water interaction at the riparian interface

    EPA Science Inventory

    Groundwater-surface water interaction (GSI) in riparian ecosystems strongly influences biological activity that controls nutrient flux and processes. Shallow groundwater in riparian zones is a hot spot for nitrogen removal processes, a storage zone for solutes, and a target for ...

  8. Riparian land-use and rehabilitation: impact on organic matter input and soil respiration.

    PubMed

    Oelbermann, Maren; Raimbault, Beverly A; Gordon, A M

    2015-02-01

    Rehabilitated riparian zones in agricultural landscapes enhance environmental integrity and provide environmental services such as carbon (C) sequestration. This study quantified differences in organic matter input, soil biochemical characteristics, and soil respiration in a 25-year-old rehabilitated (RH), grass (GRS), and undisturbed natural forest (UNF) riparian zone. Input from herbaceous vegetation was significantly greater (P < 0.05) in the GRS riparian zone, whereas autumnal litterfall was significantly greater (P < 0.05) in the RH riparian zone. Soil bulk density was significantly greater (P < 0.05) in the RH riparian zone, but its soil chemical characteristics were significantly lower. Soil respiration rates were lowest (P < 0.05) in the UNF (106 C m(-2) h(-1)), followed by the RH (169 mg C m(-2) h(-1)) and GRS (194 C m(-2) h(-1)) riparian zones. Soil respiration rates were significantly different (P < 0.05) among seasons, and were significantly correlated with soil moisture (P < 0.05) and soil temperature (P < 0.05) in all riparian zones. Soil potential microbial activity indicated a significantly different (P < 0.05) response of the microbial metabolic diversity in the RH compared to the GRS and UNF riparian zones, and principle component analysis showed a distinct difference in microbial activity among the riparian land-use systems. Rehabilitating degraded riparian zones with trees rather than GRS is a more effective approach to the long-term mitigation of CO2. Therefore, the protection of existing natural/undisturbed riparian forests in agricultural landscapes is equally important as their rehabilitation with trees, given their higher levels of soil organic C and lower soil respiration rates. PMID:25432450

  9. Riparian land-use and rehabilitation: impact on organic matter input and soil respiration.

    PubMed

    Oelbermann, Maren; Raimbault, Beverly A; Gordon, A M

    2015-02-01

    Rehabilitated riparian zones in agricultural landscapes enhance environmental integrity and provide environmental services such as carbon (C) sequestration. This study quantified differences in organic matter input, soil biochemical characteristics, and soil respiration in a 25-year-old rehabilitated (RH), grass (GRS), and undisturbed natural forest (UNF) riparian zone. Input from herbaceous vegetation was significantly greater (P < 0.05) in the GRS riparian zone, whereas autumnal litterfall was significantly greater (P < 0.05) in the RH riparian zone. Soil bulk density was significantly greater (P < 0.05) in the RH riparian zone, but its soil chemical characteristics were significantly lower. Soil respiration rates were lowest (P < 0.05) in the UNF (106 C m(-2) h(-1)), followed by the RH (169 mg C m(-2) h(-1)) and GRS (194 C m(-2) h(-1)) riparian zones. Soil respiration rates were significantly different (P < 0.05) among seasons, and were significantly correlated with soil moisture (P < 0.05) and soil temperature (P < 0.05) in all riparian zones. Soil potential microbial activity indicated a significantly different (P < 0.05) response of the microbial metabolic diversity in the RH compared to the GRS and UNF riparian zones, and principle component analysis showed a distinct difference in microbial activity among the riparian land-use systems. Rehabilitating degraded riparian zones with trees rather than GRS is a more effective approach to the long-term mitigation of CO2. Therefore, the protection of existing natural/undisturbed riparian forests in agricultural landscapes is equally important as their rehabilitation with trees, given their higher levels of soil organic C and lower soil respiration rates.

  10. Use of Standardized Visual Assessments of Riparian and Stream Condition to Manage Riparian Bird Habitat in Eastern Oregon

    NASA Astrophysics Data System (ADS)

    Cooke, Hilary A.; Zack, Steve

    2009-07-01

    The importance of riparian vegetation to support stream function and provide riparian bird habitat in semiarid landscapes suggests that standardized assessment tools that include vegetation criteria to evaluate stream health could also be used to assess habitat conditions for riparian-dependent birds. We first evaluated the ability of two visual assessments of woody vegetation in the riparian zone (corridor width and height) to describe variation in the obligate riparian bird ensemble along 19 streams in eastern Oregon. Overall species richness and the abundances of three species all correlated significantly with both, but width was more important than height. We then examined the utility of the riparian zone criteria in three standardized and commonly used rapid visual riparian assessment protocols—the USDI BLM Proper Functioning Condition (PFC) assessment, the USDA NRCS Stream Visual Assessment Protocol (SVAP), and the U.S. EPA Habitat Assessment Field Data Sheet (HAFDS)—to assess potential riparian bird habitat. Based on the degree of correlation of bird species richness with assessment ratings, we found that PFC does not assess obligate riparian bird habitat condition, SVAP provides a coarse estimate, and HAFDS provides the best assessment. We recommend quantitative measures of woody vegetation for all assessments and that all protocols incorporate woody vegetation height. Given that rapid assessments may be the only source of information for thousands of kilometers of streams in the western United States, incorporating simple vegetation measurements is a critical step in evaluating the status of riparian bird habitat and provides a tool for tracking changes in vegetation condition resulting from management decisions.

  11. The influence of riparian evapotranspiration on stream hydrology and nitrogen retention in a subhumid Mediterranean catchment

    NASA Astrophysics Data System (ADS)

    Lupon, Anna; Bernal, Susana; Poblador, Sílvia; Martí, Eugènia; Sabater, Francesc

    2016-09-01

    Riparian evapotranspiration (ET) can influence stream hydrology at catchment scale by promoting the net loss of water from the stream towards the riparian zone (i.e., stream hydrological retention). However, the consequences of stream hydrological retention on nitrogen dynamics are not well understood. To fill this gap of knowledge, we investigated changes in riparian ET, stream discharge, and nutrient chemistry in two contiguous reaches (headwater and valley) with contrasted riparian forest size in a small forested Mediterranean catchment. Additionally, riparian groundwater level (hgw) was measured at the valley reach. The temporal pattern of riparian ET was similar between reaches, and was positively correlated with hgw (ρ = 0.60) and negatively correlated with net riparian groundwater inputs (ρ < -0.55). During the vegetative period, stream hydrological retention occurred mostly at the valley reach (59 % of the time), and was accompanied by in-stream nitrate release and ammonium uptake. During the dormant period, when the stream gained water from riparian groundwater, results showed small influences of riparian ET on stream hydrology and nitrogen concentrations. Despite being a small component of annual water budgets (4.5 %), our results highlight that riparian ET drives stream and groundwater hydrology in this Mediterranean catchment and, furthermore, question the potential of the riparian zone as a natural filter of nitrogen loads.

  12. The impact of Holocene soil-geomorphic riparian development on the role of salmon- derived nutrients in the coastal temperate rainforest of southeast Alaska

    NASA Astrophysics Data System (ADS)

    D'Amore, D. V.; Bonzey, N.; Berkowitz, J.; Ruegg, J.; Bridgham, S.

    2008-12-01

    Salmon and riparian systems are linked in an ecological cycle that is important to both salmon life histories and riparian ecological functions in the coastal temperate rainforest (CTR) of southeast Alaska. Glacial rebound after the last glacial maximum during the Pleistocene expanded riparian zones by uplifting former estuaries in the CTR. The development of these lower river systems enhanced the movement of salmon into stream channels adjacent to terrestrial vegetation and increased the supply of salmon derived nutrients (SDN) to terrestrial ecosystems during the late Holocene. The flow of SDN to and from river systems has been the focus of recent research due to the potential for enhanced aquatic and terrestrial ecosystem productivity. However, there is very little known about the geomorphic development of the terrestrial and aquatic system that supports this important ecological coupling. Mass-spawning species of salmon are most often found in alluvial-fan and floodplain-channel process groups associated with specific soil geomorphic associations in southeast Alaska. We have developed an integrated model of geological controls over stream channel formation combined with soil geomorphology to provide a template for integrating studies of nutrient cycles associated with SDN in CTR streams. River systems and fish populations started to stabilize in their present configuration approximately 6ky ago, which established the primary template for soil and vegetation development in riparian zones along salmon spawning channels. Subsequent sediment delivery from the watershed formed at least two terraces on top of the estuarine base-level. A lower, younger floodplain terrace and an older terrace were identified and described and provide a range of characteristics associated with soil development in riparian zones of these distal portions of large watersheds in the CTR. Many SDN studies have not been able to distinguish the impact of SDN on terrestrial nutrient cycles due

  13. Ecophysiology of riparian cottonwoods: stream flow dependency, water relations and restoration.

    PubMed

    Rood, Stewart B; Braatne, Jeffrey H; Hughes, Francine M R

    2003-11-01

    Cottonwoods (Populus spp.) are adapted to riparian or floodplain zones throughout the Northern Hemisphere; they are also used as parents for fast-growing hybrid poplars. We review recent ecophysiological studies of the native cottonwoods Populus angustifolia James, P. balsamifera L., P. deltoides Marsh., P. fremontii S. Watson and P. trichocarpa T. & G. in North America, and P. nigra L. in Europe. Variation exists within and across species and hybrids; however, all riparian cottonwoods are dependent on shallow alluvial groundwater that is linked to stream water, particularly in semi-arid regions. This conclusion is based on studies of their natural occurrence, decline following river damming and dewatering (water removal), water relations, isotopic composition of xylem water, and by the establishment of cottonwoods along formerly barren natural channels after flow augmentation in response to the conveyance of irrigation water. When alluvial groundwater is depleted as a result of river dewatering or groundwater pumping, riparian cottonwoods exhibit drought-stress responses including stomatal closure and reduced transpiration and photosynthesis, altered 13C composition, reduced predawn and midday water potentials, and xylem cavitation. These physiological responses are accompanied by morphological responses including reduced shoot growth, altered root growth, branch sacrifice and crown die-back. In severe cases, mortality occurs. For example, severe dewatering of channels of the braided Big Lost River in Idaho led to mortality of the narrowleaf cottonwood, P. angustifolia, and adjacent sandbar willows, Salix exigua Nutt., within 5 years, whereas riparian woodlands thrived along flowing channels nearby. The conservation and restoration of cottonwoods will rely on the provision of river flow regimes that satisfy these ecophysiological requirements for survival, growth and reproduction.

  14. Riparian reforestation: are there changes in soil carbon and soil microbial communities?

    PubMed

    Mackay, J E; Cunningham, S C; Cavagnaro, T R

    2016-10-01

    Reforestation of pastures in riparian zones has the potential to decrease nutrient runoff into waterways, provide both terrestrial and aquatic habitat, and help mitigate climate change by sequestering carbon (C). Soil microbes can play an important role in the soil C cycle, but are rarely investigated in studies on C sequestration. We surveyed a chronosequence (0-23years) of mixed-species plantings in riparian zones to investigate belowground (chemical and biological) responses to reforestation. For each planting, an adjacent pasture was surveyed to account for differences in soil type and land-use history among plantings. Two remnant woodlands were included in the survey as indicators of future potential of plantings. Both remnant woodlands had significantly higher soil organic C (SOC) content compared with their adjacent pastures. However, there was no clear trend in SOC content among plantings with time since reforestation. The substantial variability in SOC sequestration among plantings was possibly driven by differences in soil moisture among plantings and the inherent variability of SOC content among reference pastures adjacent to plantings. Soil microbial phospholipid fatty acids (PLFA, an indicator of microbial biomass) and activities of decomposition enzymes (β-glucosidase and polyphenol oxidase) did not show a clear trend with increasing planting age. Despite this, there were positive correlations between total SOC concentration and microbial indicators (total PLFA, fungal PLFA, bacterial PLFA and activities of decomposition enzymes) across all sites. The soil microbial community compositions (explored using PLFA markers) of older plantings were similar to those of remnant woodlands. There was a positive correlation between the soil carbon:nitrogen (C:N) and fungal:bacterial (F:B) ratios. These data indicate that in order to maximise SOC sequestration, we need to take into account not only C inputs, but the microbial processes that regulate SOC cycling

  15. Riparian ecosystems in human cancers

    PubMed Central

    Alfarouk, Khalid O; Ibrahim, Muntaser E; Gatenby, Robert A; Brown, Joel S

    2013-01-01

    Intratumoral evolution produces extensive genetic heterogeneity in clinical cancers. This is generally attributed to an increased mutation rate that continually produces new genetically defined clonal lineages. Equally important are the interactions between the heritable traits of cancer cells and their microenvironment that produces natural selection favoring some clonal ‘species’ over others. That is, while mutations produce the heritable variation, environmental selection and cellular adaptation govern the strategies (and genotypes) that can proliferate within the tumor ecosystem. Here we ask: What are the dominant evolutionary forces in the cancer ecosystem? We propose that the tumor vascular network is a common and primary cause of intratumoral heterogeneity. Specifically, variations in blood flow result in variability in substrate, such as oxygen, and metabolites, such as acid, that serve as critical, but predictable, environmental selection forces. We examine the evolutionary and ecological consequences of variable blood flow by drawing an analogy to riparian habitats within desert landscapes. We propose that the phenotypic properties of cancer cells will exhibit predictable spatial variation within tumor phenotypes as a result of proximity to blood flow. Just as rivers in the desert create an abrupt shift from the lush, mesic riparian vegetation along the banks to sparser, xeric and dry-adapted plant species in the adjacent drylands, we expect blood vessels within tumors to promote similarly distinct communities of cancer cells that change abruptly with distance from the blood vessel. We propose vascular density and blood flow within a tumor as a primary evolutionary force governing variations in the phenotypic properties of cancer cells thus providing a unifying ecological framework for understanding intratumoral heterogeneity. PMID:23396634

  16. Impacts of an Invasive Snail (Tarebia granifera) on Nutrient Cycling in Tropical Streams: The Role of Riparian Deforestation in Trinidad, West Indies

    PubMed Central

    Moslemi, Jennifer M.; Snider, Sunny B.; MacNeill, Keeley; Gilliam, James F.; Flecker, Alexander S.

    2012-01-01

    Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N. PMID:22761706

  17. Impacts of an invasive snail (Tarebia granifera) on nutrient cycling in tropical streams: the role of riparian deforestation in Trinidad, West Indies.

    PubMed

    Moslemi, Jennifer M; Snider, Sunny B; Macneill, Keeley; Gilliam, James F; Flecker, Alexander S

    2012-01-01

    Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N.

  18. Nitrate retention in riparian ground water at natural and elevated nitrate levels in north central Minnesota.

    PubMed

    Duff, John H; Jackman, Alan P; Triska, Frank J; Sheibley, Richard W; Avanzino, Ronald J

    2007-01-01

    The relationship between local ground water flows and NO(3)(-) transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO(3)(-) concentrations decreased from approximately 3 mg N L(-1) beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L(-1) at wells 1 to 3 m from the channel. The Cl(-) concentrations and NO(3)/Cl ratios decreased toward the channel indicating NO(3)(-) dilution and biotic retention. In the bankside well transect parallel to the stream, two distinct ground water environments were observed: an alluvial environment upstream of a relict beaver dam influenced by stream water and a hillslope environment downstream of the relict beaver dam. Nitrate was elevated to levels representative of agricultural runoff in a third well transect located approximately 5 m from the stream to assess the effectiveness of the riparian zone as a NO(3)(-) sink. Subsurface NO(3)(-) injections revealed transport of up to 15 mg N L(-1) was nearly conservative in the alluvial riparian environment. Addition of glucose stimulated dissolved oxygen uptake and promoted NO(3)(-) retention under both background and elevated NO(3)(-) levels in summer and winter. Disappearance of added NO(3)(-) was followed by transient NO(2)(-) formation and, in the presence of C(2)H(2), by N(2)O formation, demonstrating potential denitrification. Under current land use, most NO(3)(-) associated with local ground water is biotically retained or diluted before reaching the channel. However, elevating NO(3)(-) levels through agricultural cultivation would likely result in increased NO(3)(-) transport to the channel.

  19. Nitrate retention in riparian ground water at natural and elevated nitrate levels in North Central Minnesota

    USGS Publications Warehouse

    Duff, J.H.; Jackman, A.P.; Triska, F.J.; Sheibley, R.W.; Avanzino, R.J.

    2007-01-01

    The relationship between local ground water flows and NO3- transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO3- concentrations decreased from ???3 mg N L-1 beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L-1 at wells 1 to 3 m from the channel. The Cl- concentrations and NO3/Cl ratios decreased toward the channel indicating NO3- dilution and biotic retention. In the bankside well transect parallel to the stream, two distinct ground water environments were observed: an alluvial environment upstream of a relict beaver dam influenced by stream water and a hillslope environment downstream of the relict beaver dam. Nitrate was elevated to levels representative of agricultural runoff in a third well transect looted ???5 m from the stream to assess the effectiveness of the riparian zone as a NO3- sink. Subsurface NO3- injections revealed transport of up to 15 mg N L-1 was nearly conservative in the alluvial riparian environment. Addition of glucose stimulated dissolved oxygen uptake and promoted NO3- retention under both background and elevated NO 3- levels in summer and winter. Disappearance of added NO3- was followed by transient NO2- formation and, in the presence of C2H2, by N2O formation, demonstrating potential denitrification. Under current land use, most NO3- associated with local ground water is biotically retained or diluted before reaching the channel. However, elevating NO 3- levels through agricultural cultivation would likely result in increased NO3- transport to the channel. ?? ASA, CSSA, SSSA.

  20. Impact of outflow from the Guadiana River on the distribution of suspended particulate matter and nutrients in the adjacent coastal zone

    NASA Astrophysics Data System (ADS)

    Cravo, Alexandra; Madureira, Miguel; Felícia, Helena; Rita, F.; Bebianno, Maria J.

    2006-10-01

    In this study we collected surface water samples from the coastal area adjacent to the Guadiana estuary during winter for 3 consecutive years to assess the impact of the Guadiana outflow upon the concentration and spatial distribution of suspended particulate matter and nutrients (nitrate, phosphate, and silicate). Deeper water samples were also collected near the river mouth in water greater than 10 m in depth. Our results indicate that the maximal surface influence of the Guadiana outflow is close to the mouth of the Guadiana River, at the 10-m isobath, where the highest concentrations of suspended particulate matter (SPM) and nutrients were recorded, as well as the lowest salinity. SPM and nutrient concentrations decrease with increased water depth, while salinity increased. Beyond the 10-m isobath, toward the ocean, nutrient concentrations decreased gradually with increasing salinity. Nutrient concentrations showed a conservative behaviour only during the last of the three sampling periods. The impact of Guadiana outflow was especially low when river discharge was low, however, after periods of peak rainfall the river outflow increased enormously and the impact of SPM and nutrients (more than an order of magnitude higher than normal) was observed, particularly around the mouth of the estuary. This impact involved the development of a fingerprint plume that represents a net export of SPM and nutrients to the coastal area. This plume had a width of about 10-15 km, and despite being centred slightly east of the mouth of the Guadiana River, tended to migrate westward. The increase in N compounds was more significant than increases in P and Si, is reflected in high N:P and N:Si nutrient ratios. In water depths in excess of 10 m, the effect of the Guadiana outflow was most evident until 5 m depth. It is expected that with the completion of the biggest dam in Europe along the Guadiana River, the outflow of the river will be markedly reduced, especially during summer

  1. Characterization of terrestrial organic matter transported through the Lena River Delta (NE Siberia) to its adjacent nearshore zone using lignin phenols, δ13C and ∆14C

    NASA Astrophysics Data System (ADS)

    Winterfeld, M.; Goni, M. A.; Just, J.; Hefter, J.; Han, P.; Mollenhauer, G.

    2014-12-01

    The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OMterr) from its southernmost reaches near Lake Baikal to the coastal zone of the Laptev Sea and the Arctic Ocean. Permafrost soils from its vast catchment area store huge amounts of pre-aged OM, which is expected to be remobilized due to climate warming. To characterize the composition and vegetation sources of OM discharged by the Lena River, we analyzed the lignin phenol and carbon isotopic composition (δ13C and ∆14C) in total suspended matter (TSM) from surface waters collected in spring and summer, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta. A simple linear mixing model based on the lignin phenol distributions indicates OM in TSM samples from the delta and Buor Khaya Bay surface sediments contains comparable contributions from gymnosperm sources, which are primarily from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small area covered by tundra (~12% of total catchment), the input of tundra-derived OM input is substantial and likely to increase in a warming Arctic. Radiocarbon compositions (∆14C) of bulk OM in TSM samples varied from -55 to -391‰, i.e. 14C ages of 395 to 3920 yrs BP. Using δ13C compositions to estimate the fraction of phytoplankton-derived OM and assuming that this material has a modern 14C signature, we inferred the ∆14C compositions of OMterr in TSM exported by the Lena River to range between -190 and -700‰. Such variability in the ages of OMTERR (i.e. 1640 to 9720 14C yrs BP) reflects the heterogeneous composition and residence time of OM in the Lena River catchment soils (Holocene to Pleistocene ages). Lignin phenol and ∆14C compositions of surface sediments from the adjacent Buor Khaya Bay suggest that OMTERR deposited there is older and more degraded than materials present in river particles and catchment soils. Stronger

  2. Habitat selection by juvenile Swainson’s thrushes (Catharus ustulatus) in headwater riparian areas, northwestern Oregon, USA

    USGS Publications Warehouse

    Jenkins, Stephanie R.; Betts, Matthew G.; Huso, Manuela M.; Hagar, Joan C.

    2013-01-01

    Lower order, non-fish-bearing streams, often termed “headwater streams”, have received minimal research effort and protection priority, especially in mesic forests where distinction between riparian and upland vegetation can be subtle. Though it is generally thought that breeding bird abundance is higher in riparian zones, little is known about species distributions when birds are in their juvenile stage – a critical period in terms of population viability. Using radio telemetry, we examined factors affecting habitat selection by juvenile Swainson’s thrushes during the post-breeding period in headwater basins in the Coast Range of Oregon, USA. We tested models containing variables expected to influence the amount of food and cover (i.e., deciduous cover, coarse wood volume, and proximity to stream) as well as models containing variables that are frequently measured and manipulated in forest management (i.e., deciduous and coniferous trees separated into size classes). Juvenile Swainson’s thrushes were more likely to select locations with at least 25% cover of deciduous, mid-story vegetation and more than 2.0 m3/ha of coarse wood within 40 m of headwater streams. We conclude that despite their small and intermittent nature, headwater streams and adjacent riparian areas are selected over upland areas by Swainson’s thrush during the postfledging period in the Oregon Coast Range.

  3. Heavy metal enrichment in the riparian sediments and soils of the Three Gorges Reservoir, China

    NASA Astrophysics Data System (ADS)

    Tang, Q.; Bao, Y.; He, X.; Wen, A.

    2015-03-01

    The Three Gorges Reservoir encompasses a riparian zone with a vertical height of 30 m and a total area of 349 km2 that has been subjected to alternate inundation and exposure due to regular impoundment. Sedimentation on the riparian landforms constitutes an important pathway for riverine contaminant redistribution. In an attempt to understand heavy metal enrichment since water inundation, riparian sediments and soils were sampled along five transects in a typical riparian zone composed of cultivated bench terraces in the middle reaches. Heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) were determined to characterize the lateral distribution and vertical transfer ratio. The results indicated that all heavy metals were enriched to varying extents both in the riparian sediments and soils, compared with regional background contents in soils and the reference levels in sediments. However, heavy metal levels in the riparian sediments were generally higher than those in the riparian soils, while those in the upper riparian soils (0-5 cm) were overall slightly higher than those in the lower riparian soils (5-10 cm). There was a decreasing trend of heavy metal contents with increasing elevation. The elevated levels of heavy metals in the riparian sediments may be attributed to sediment yields from upstream anthropogenic sources, especially during major rainstorms in the wet season when large loads of contaminated sediment may be produced from diffuse source areas. Heavy metals can also be adsorbed to pure sediment in the course of mobilization or after deposition. Considering that the riparian soils are local weathering products without mobilization, the enrichment of heavy metals may principally be ascribed to chemical adsorption from dissolved fractions or vertical transfer from overlaid sediments. Heavy metal enrichment may further be affected by the specific type of hydrologic regime such that relatively long flooding duration caused by water impoundment and natural floods

  4. Influence of multi-scale hydrologic controls on river network connectivity and riparian function

    EPA Science Inventory

    The ecological functions of rivers and streams and their associated riparian zones are strongly influenced by surface and subsurface hydrologic routing of water within river basins and river networks. Hydrologic attributes of the riparian area for a given stream reach are typica...

  5. Dynamic river networks as the context for evaluating riparian influence on river basin solute export

    EPA Science Inventory

    Many studies have examined the influence of riparian areas on nitrogen as water drains from hillslopes and through riparian zones at the stream reach scale. Most of these studies have been conducted along relatively small streams. However, water quality concerns typically deal wi...

  6. Sensitivity of a semi-arid riparian ecosystem to climatic variability in the southwestern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climatic change will have strong impacts on riverine ecosystems and their associated riparian zones. In the southwestern United States, conservation and restoration of riparian habitats has become a priority for resource management agencies and conservation groups, and these areas are biodiversity h...

  7. The role of riparian vegetation in protecting and improving water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian vegetation influences stream water quality through processes involving both the live vegetation and its detritus, and, in both the riparian zone and the channel. Individual processes range from direct chemical uptake by plants to indirect influences such as supplying detritus to channels an...

  8. Report calls for riparian protection

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    A 22 March report by The (U.S.) National Academies calls for the protection and restoration of riparian areas in the United States. However, it concedes that key difficulties in this endeavor include the lack of basic information about the extent and ecological health of these areas, and even a precise ecological definition of what a riparian area is.The report, “Riparian Areas: Functions and Strategies for Management” prepared by the Water Science and Technology Board of the National Research Council, states that “restoration of riparian functions along America's water bodies should be a national goal.”

  9. Ecophysiological Competence of Populus alba L., Fraxinus angustifolia Vahl., and Crataegus monogyna Jacq. Used in Plantations for the Recovery of Riparian Vegetation

    NASA Astrophysics Data System (ADS)

    Manzanera, Jose A.; Martínez-Chacón, Maria F.

    2007-12-01

    In many semi-arid environments of Mediterranean ecosystems, white poplar ( Populus alba L.) is the dominant riparian tree and has been used to recover degraded areas, together with other native species, such as ash ( Fraxinus angustifolia Vahl.) and hawthorn ( Crataegus monogyna Jacq.). We addressed three main objectives: (1) to gain an improved understanding of some specific relationships between environmental parameters and leaf-level physiological factors in these riparian forest species, (2) to compare the leaf-level physiology of these riparian species to each other, and (3) to compare leaf-level responses within native riparian plots to adjacent restoration plots, in order to evaluate the competence of the plants used for the recovery of those degraded areas. We found significant differences in physiological performance between mature and young white poplars in the natural stand and among planted species. The net assimilation and transpiration rates, diameter, and height of white poplar plants were superior to those of ash and hawthorn. Ash and hawthorn showed higher water use efficiency than white poplar. White poplar also showed higher levels of stomatal conductance, behaving as a fast-growing, water-consuming species with a more active gas exchange and ecophysiological competence than the other species used for restoration purposes. In the restoration zones, the planted white poplars had higher rates of net assimilation and water use efficiency than the mature trees in the natural stand. We propose the use of white poplar for the rapid restoration of riparian vegetation in semi-arid Mediterranean environments. Ash and hawthorn can also play a role as accompanying species for the purpose of biodiversity.

  10. Riparian forest composition affects stream litter decomposition despite similar microbial and invertebrate communities.

    PubMed

    Kominoski, John S; Marczak, Laurie B; Richardson, John S

    2011-01-01

    Cross-boundary flows of energy and nutrients link biodiversity and functioning in adjacent ecosystems. The composition of forest tree species can affect the structure and functioning of stream ecosystems due to physical and chemical attributes, as well as changes in terrestrial resource subsidies. We examined how variation in riparian canopy composition (coniferous, deciduous, mixed) affects adjacent trophic levels (invertebrate and microbial consumers) and decomposition of organic matter in small, coastal rainforest streams in southwestern British Columbia. Breakdown rates of higher-quality red alder (Alnus rubra) litter were faster in streams with a greater percentage of deciduous than coniferous riparian canopy, whereas breakdown rates of lower-quality western hemlock (Tsuga heterophylla) litter were independent of riparian forest composition. When invertebrates were excluded using fine mesh, breakdown rates of both litter species were an order of magnitude less and were not significantly affected by riparian forest composition. Stream invertebrate and microbial communities were similar among riparian forest composition, with most variation attributed to leaf litter species. Invertebrate taxa richness and shredder biomass were higher in A. rubra litter; however, taxa evenness was greatest for T. heterophylla litter and both litter species in coniferous streams. Microbial community diversity (determined from terminal restriction fragment length polymorphisms) was unaffected by riparian forest or litter species. Fungal allele richness was higher than bacterial allele richness, and microbial communities associated with lower-quality T. heterophylla litter had higher diversity (allele uniqueness and richness) than those associated with higher-quality A. rubra litter. Percent variation in breakdown rates was mostly attributed to riparian forest composition in the presence of invertebrates and microbes; however, stream consumer biodiversity at adjacent trophic levels

  11. Featured collection introduction: riparian ecosystems and buffers II

    EPA Science Inventory

    Riparian ecosystems, the interface of terrestrial and aquatic systems, are zones of high biodiversity (Naiman et al., 1993), rapid biogeochemical activity (Vidon et al., 2010), complex hydrologic activity (Mayer et al., 2010a), and offer solace that can bestow significant mental ...

  12. Innovative interdisciplinary approaches in catchment hydrology: on the potential for diatoms and thermal infrared imagery for documenting spatio-temporal dynamics and connectivity of saturated areas in the hillslope-riparian zone-stream system

    NASA Astrophysics Data System (ADS)

    Pfister, L.; Martínez-Carreras, N.; Wetzel, C.; Ector, L.; Frentress, J.; McDonnell, J. J.

    2012-04-01

    years, our research activities have been focusing on the exploration of new research avenues for untapping new insights on inherent hydrological processes, guiding water source and flowpaths. Here, we will present the most recent results obtained to date from interdisciplinary proof-of-concept studies carried out in the Weierbach experimental watershed. New research avenues, such as the introduction of terrestrial diatom tracing in flood waves, will hopefully contribute to reduce uncertainties in the determination of the onset/cessation of surface runoff and connectivity in the hillslope-riparian zone-stream system. Likewise, thermal infrared imaging has shown considerable potential for tracing surface water flowpaths, connectivity, as well as saturated area dynamics.

  13. Rhizosphere dynamics of two riparian plant species from the water fluctuation zone of Three Gorges Reservoir, P.R. China - pH, oxygen and LMWOA monitoring during short flooding events

    NASA Astrophysics Data System (ADS)

    Schreiber, Christina M.; Schurr, Ulrich; Zeng, Bo; Höltkemeier, Agnes; Kuhn, Arnd J.

    2010-05-01

    Since the construction of the Three Gorges Dam at the Yangtze River in China, the reservoir management created a new 30m water fluctuation zone 45-75m above the original water level. Only species well adapted to long-time flooding (up to several months) will be able to vegetate the river banks and replace the original vegetation. To investigate how common species of the riverbanks cope with submergence, Alternanthera philoxeroides Mart. and Arundinella anomala Steud., two flooding resistant riparian species, have been examined in a rhizotron environment. Short-time (2 days waterlogging, 2 days flooding, 2 days recovery) flooding cycles in the original substrate and long time (14 days waterlogging, flooding, recovery) flooding cycles, in original substrate and sterile glass bead substrate, have been simulated in floodable two-way access rhizotrons. Oxygen- and pH-sensitive foils (planar optodes, PreSens) automatically monitored root reaction in a confined space (2cm2 each) on the backside of the rhizotron, while soil solution samples were taken 2 times a day from the other side of the rhizotron at the corresponding area through filter and steel capillaries. The samples were analyzed by capillary electrophoresis for low molecular weight organic acids (LMWOA, i.e. oxalic, formic, succinic, malic, acetic, glyoxylic, lactic and citric acid). Results show diurnal rhythms of rhizospheric acidification for both species in high resolution, combined with oxygen entry into the root surrounding during waterlogged state. Flooding caused stronger acidification in the rhizosphere, that were however not accompanied by increased occurrence of LMWOA except for acetic and glyoxylic acid. First results from longer flooding periods show stable diurnal rhythms during waterlogging, but no strongly increased activity during the flooding event. Performance of the two species is not hampered by being waterlogged, and they follow a silencing strategy during a longer phase of anoxia without

  14. Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California: Chapter CC of Evolution of sedimentary basins/onshore oil and gas investigations - Santa Maria province

    USGS Publications Warehouse

    Willingham, C. Richard; Rietman, Jan D.; Heck, Ronald G.; Lettis, William R.

    2013-01-01

    The Hosgri Fault Zone trends subparallel to the south-central California coast for 110 km from north of Point Estero to south of Purisima Point and forms the eastern margin of the present offshore Santa Maria Basin. Knowledge of the attributes of the Hosgri Fault Zone is important for petroleum development, seismic engineering, and environmental planning in the region. Because it lies offshore along its entire reach, our characterizations of the Hosgri Fault Zone and adjacent structures are primarily based on the analysis of over 10,000 km of common-depth-point marine seismic reflection data collected from a 5,000-km2 area of the central and eastern parts of the offshore Santa Maria Basin. We describe and illustrate the along-strike and downdip geometry of the Hosgri Fault Zone over its entire length and provide examples of interpreted seismic reflection records and a map of the structural trends of the fault zone and adjacent structures in the eastern offshore Santa Maria Basin. The seismic data are integrated with offshore well and seafloor geologic data to describe the age and seismic appearance of offshore geologic units and marker horizons. We develop a basin-wide seismic velocity model for depth conversions and map three major unconformities along the eastern offshore Santa Maria Basin. Accompanying plates include maps that are also presented as figures in the report. Appendix A provides microfossil data from selected wells and appendix B includes uninterpreted copies of the annotated seismic record sections illustrated in the chapter. Features of the Hosgri Fault Zone documented in this investigation are suggestive of both lateral and reverse slip. Characteristics indicative of lateral slip include (1) the linear to curvilinear character of the mapped trace of the fault zone, (2) changes in structural trend along and across the fault zone that diminish in magnitude toward the ends of the fault zone, (3) localized compressional and extensional structures

  15. Rapid riparian buffer width and quality analysis using lidar in South Carolina

    NASA Astrophysics Data System (ADS)

    Akturk, Emre

    The importance of protecting water quality and aquatic resources are increasing because of harmful human impacts within and around waterways. Establishing or restoring functional riparian areas protect water quality and are a good mechanism to conserve aquatic systems, plants, and wildlife. Laser-based remote sensing technology offers a high resolution approach to both characterize and document changes in riparian buffer zones (RBZs). The objectives of this study were to build a model to calculate riparian buffer width on both sides of a stream using a LiDAR-derived slope variable, to classify riparian buffers and determine their quality, and to evaluate the appropriateness of using LiDAR in riparian buffer assessment. For this purpose, RBZs were delineated for Hunnicutt and King Creek, which are located in Oconee and Pickens counties, in South Carolina. Results show that LiDAR was effective in delineating required riparian buffer widths based on the topography slope of upstream areas, and to calculate the ratio of tree cover in those riparian buffer zones to qualify them. Furthermore, the riparian buffer assessment model that was created in this research has potential for use in different sites and different studies.

  16. Spatial characterization of riparian buffer effects on sediment loads from watershed systems.

    PubMed

    Momm, Henrique G; Bingner, Ronald L; Yuan, Yongping; Locke, Martin A; Wells, Robert R

    2014-09-01

    Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural landscapes can modify the characteristics of overland flow, promoting sediment deposition and nutrient filtering. Watershed simulation tools, such as the USDA-Annualized Agricultural Non-Point Source (AnnAGNPS) pollution model, typically require detailed information for each riparian buffer zone throughout the watershed describing the location, width, vegetation type, topography, and possible presence of concentrated flow paths through the riparian buffer zone. Research was conducted to develop GIS-based technology designed to spatially characterize riparian buffers and to estimate buffer efficiency in reducing sediment loads in a semiautomated fashion at watershed scale. The methodology combines modeling technology at different scales, at individual concentrated flow paths passing through the riparian zone, and at watershed scales. At the concentrated flow path scale, vegetative filter strip models are applied to estimate the sediment-trapping efficiency for each individual flow path, which are aggregated based on the watershed subdivision and used in the determination of the overall impact of the riparian vegetation at the watershed scale. This GIS-based technology is combined with AnnAGNPS to demonstrate the effect of riparian vegetation on sediment loadings from sheet and rill and ephemeral gully sources. The effects of variability in basic input parameters used to characterize riparian buffers, onto generated outputs at field scale (sediment trapping efficiency) and at watershed scale (sediment loadings from different sources) were evaluated and quantified. The AnnAGNPS riparian buffer component represents an important step in understanding and accounting for the effect of riparian

  17. Spatial characterization of riparian buffer effects on sediment loads from watershed systems.

    PubMed

    Momm, Henrique G; Bingner, Ronald L; Yuan, Yongping; Locke, Martin A; Wells, Robert R

    2014-09-01

    Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural landscapes can modify the characteristics of overland flow, promoting sediment deposition and nutrient filtering. Watershed simulation tools, such as the USDA-Annualized Agricultural Non-Point Source (AnnAGNPS) pollution model, typically require detailed information for each riparian buffer zone throughout the watershed describing the location, width, vegetation type, topography, and possible presence of concentrated flow paths through the riparian buffer zone. Research was conducted to develop GIS-based technology designed to spatially characterize riparian buffers and to estimate buffer efficiency in reducing sediment loads in a semiautomated fashion at watershed scale. The methodology combines modeling technology at different scales, at individual concentrated flow paths passing through the riparian zone, and at watershed scales. At the concentrated flow path scale, vegetative filter strip models are applied to estimate the sediment-trapping efficiency for each individual flow path, which are aggregated based on the watershed subdivision and used in the determination of the overall impact of the riparian vegetation at the watershed scale. This GIS-based technology is combined with AnnAGNPS to demonstrate the effect of riparian vegetation on sediment loadings from sheet and rill and ephemeral gully sources. The effects of variability in basic input parameters used to characterize riparian buffers, onto generated outputs at field scale (sediment trapping efficiency) and at watershed scale (sediment loadings from different sources) were evaluated and quantified. The AnnAGNPS riparian buffer component represents an important step in understanding and accounting for the effect of riparian

  18. Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

    SciTech Connect

    Clarke, S.H. Jr. )

    1992-02-01

    Two upper Cenozoic depositional sequences of principally marine strata about 4,000 m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, later Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. Youthful tectonic activity related to Gorda-North American plate convergence indicates an active Cascadia subduction zone and strong partial coupling between these plates. Structures of the northeastern margin of the Eel River basin are principally north-northwest-trending, east-northeast-dipping thrust and reverse faults that form imbricate thrust fans. The Coastal belt fault, the early Tertiary accretionary suture between the Franciscan Central and Coastal belts, can be traced from Arcata Bay northward offshore to the southern Oregon border. It is tentatively extended farther northward based on aeromagnetic data to an offshore position west of Cape Blanco. Thereafter, it may coincide with the offshore Fulmar fault. The Cascadia subduction zone (CSZ) does not join the Mendocino transform fault at the commonly depicted offshore location of the Mendocino triple junction (MTJ). Instead, the CSZ extends southeastward around the southern Eel River basin and shoreward along Mendocino Canyon to join the Petrolia shear zone. Similarly, the Mendocino fault may extend shoreward via Mattole Canyon and join the Cooskie shear zone. These two shear zones intersect onshore north of the King Range, and the area of their intersection is the probable location of the MTJ.

  19. Water sources and mixing in riparian wetlands revealed by tracers and geospatial analysis

    NASA Astrophysics Data System (ADS)

    Lessels, Jason S.; Tetzlaff, Doerthe; Birkel, Christian; Dick, Jonathan; Soulsby, Chris

    2016-01-01

    Mixing of waters within riparian zones has been identified as an important influence on runoff generation and water quality. Improved understanding of the controls on the spatial and temporal variability of water sources and how they mix in riparian zones is therefore of both fundamental and applied interest. In this study, we have combined topographic indices derived from a high-resolution Digital Elevation Model (DEM) with repeated spatially high-resolution synoptic sampling of multiple tracers to investigate such dynamics of source water mixing. We use geostatistics to estimate concentrations of three different tracers (deuterium, alkalinity, and dissolved organic carbon) across an extended riparian zone in a headwater catchment in NE Scotland, to identify spatial and temporal influences on mixing of source waters. The various biogeochemical tracers and stable isotopes helped constrain the sources of runoff and their temporal dynamics. Results show that spatial variability in all three tracers was evident in all sampling campaigns, but more pronounced in warmer dryer periods. The extent of mixing areas within the riparian area reflected strong hydroclimatic controls and showed large degrees of expansion and contraction that was not strongly related to topographic indices. The integrated approach of using multiple tracers, geospatial statistics, and topographic analysis allowed us to classify three main riparian source areas and mixing zones. This study underlines the importance of the riparian zones for mixing soil water and groundwater and introduces a novel approach how this mixing can be quantified and the effect on the downstream chemistry be assessed.

  20. Water sources and mixing in riparian wetlands revealed by tracers and geospatial analysis

    PubMed Central

    Tetzlaff, Doerthe; Birkel, Christian; Dick, Jonathan; Soulsby, Chris

    2016-01-01

    Abstract Mixing of waters within riparian zones has been identified as an important influence on runoff generation and water quality. Improved understanding of the controls on the spatial and temporal variability of water sources and how they mix in riparian zones is therefore of both fundamental and applied interest. In this study, we have combined topographic indices derived from a high‐resolution Digital Elevation Model (DEM) with repeated spatially high‐resolution synoptic sampling of multiple tracers to investigate such dynamics of source water mixing. We use geostatistics to estimate concentrations of three different tracers (deuterium, alkalinity, and dissolved organic carbon) across an extended riparian zone in a headwater catchment in NE Scotland, to identify spatial and temporal influences on mixing of source waters. The various biogeochemical tracers and stable isotopes helped constrain the sources of runoff and their temporal dynamics. Results show that spatial variability in all three tracers was evident in all sampling campaigns, but more pronounced in warmer dryer periods. The extent of mixing areas within the riparian area reflected strong hydroclimatic controls and showed large degrees of expansion and contraction that was not strongly related to topographic indices. The integrated approach of using multiple tracers, geospatial statistics, and topographic analysis allowed us to classify three main riparian source areas and mixing zones. This study underlines the importance of the riparian zones for mixing soil water and groundwater and introduces a novel approach how this mixing can be quantified and the effect on the downstream chemistry be assessed. PMID:27478256

  1. Establishing a baseline on the distribution and pattern of occurrence of Salvadora persica L. with meteorological data and assessing its adaptation in the adjacent warmed-up zones

    NASA Astrophysics Data System (ADS)

    Khan, Amin U.; Sharif, Faiza; Hamza, Ali

    2016-04-01

    The natural occurrence of Salvadora persica L., stretching from the coastal area of the Arabian sea to northward along the Indus floodplains, was surveyed to document the pattern of its occurrence with the available meteorological record showing increasing trends of frost northwards. Information was compiled from various sources to generate the past and present temperature data in order to establish relationship between the changing temperature factors and the extent of the area available due to climate change over the years for introducing species beyond its range of natural distribution. In addition, the species was experimentally introduced in the warmed-up zones to monitor its performance and to evaluate its adaptability. The reconnaissance survey showed that the natural populations of thorn forest communities with S. persica, as associate, are now surviving only as degraded remnants. Its common occurrence is documented in zones where the mean winter temperatures are above the threshold level of frost, whereas it is rarely found in zones where it drops below this level for a single month, which seems to be its range edge. S. persica does not occur in zones where low temperature could persist for 2 months. Recent temperature data suggests that the month of December has warmed up above the threshold level; therefore, it was expected that correspondingly the range edge of the frost-sensitive species has potentially shifted further northwards. The response of the species introduced at the experimental sites beyond its natural occurrence suggests high survival and growth, demonstrating its adaptability to the new sites beyond its limit of distribution.

  2. Riparian vegetation controls on the hydraulic geometry of streams

    NASA Astrophysics Data System (ADS)

    McBride, M.

    2010-12-01

    A synthesis of field measurements, remote observations, and numerical modeling techniques highlights the significance of riparian vegetation in determining the geometry of streams and impacting sediment transport dynamics in temperate, Piedmont regions. Specifically, forested and grassy riparian vegetation establish streams with significantly different widths and with different timescales for attaining a state of dynamic equilibrium. The interactions between riparian vegetation, channel form, and channel dynamics are scale dependent. Scale dependency arises because of variations in ratios of vegetation length scales and geomorphic scales (e.g., channel width and depth). Stream reaches with grassy vegetation experience more frequent overbank discharges, migrate more quickly, and exhibit a more classic dynamic equilibrium than forested reaches. These phenomena are relevant to current watershed management efforts that aim to reduce sediment and nutrient loads to receiving water bodies, such as the Chesapeake Bay. The reforestation of riparian buffers is a common restoration technique that intends to improve water quality, temperature regimes, and in-stream physical habitat. Passive reforestation of riparian areas along a tributary to Sleepers River in Danville, VT, USA caused an increase in channel width and cross-sectional area over a 40-year period. From a comparison of historical records and current cross-sectional dimensions, the channel widening resulted in the mobilization of approximately 85 kg/ha/yr of floodplain sediments. Long-term monitoring of suspended sediments in an adjacent watershed indicates that this sediment source may account for roughly 40 percent of the total suspended sediment load. In some instances, increased sediment loads associated with channel widening may be an unforeseen consequence that compromises riparian restoration efforts.

  3. Surface Water and Groundwater Nitrogen Dynamics in a Well Drained Riparian Forest within a Poorly Drained Agricultural Landscape

    EPA Science Inventory

    The effectiveness of riparian zones in mitigating nutrients in ground and surface water depends on the climate, management and hydrogeomorphology of a site. The purpose of this study was to determine the efficacy of a well-drained, mixed-deciduous riparian forest to buffer a ri...

  4. Amphibian and reptile abundance in riparian and upslope areas of five forest types in western Oregon

    USGS Publications Warehouse

    Gomez, D.M.; Anthony, R.G.

    1996-01-01

    We compared species composition and relative abundance of herpetofauna between riparian and upslope habitats among 5 forest types (shrub, open sapling-pole, large sawtimber and old-growth conifer forests, and deciduous forests) in Western Oregon. Riparian- and upslope- associated species were identified based on capture frequencies from pitfall trapping. Species richness was similar among forest types but slightly greater in the shrub stands. The abundances of 3 species differed among forest types. Total captures was highest in deciduous forests, intermediate in the mature conifer forests, and lowest in the 2 young coniferous forests. Species richness was similar between stream and upslope habitats; however, captures were higher in riparian than upslope habitat. Tailed frogs (Ascaphus truei), Dunn's salamanders (Plethodon dunni), roughskin newts(Tanicha granulosa), Pacific giant salamanders (Dicamptodon tenebrosus) and red-legged frogs(Rana aurora) were captured more frequently in riparian than upslope habitats. Of these species the red-legged frog and Pacific giant salamander may depend on riparian habitat for at least part of their life requirements, while tailed frogs, Dunn's salamanders and roughskin newts appear to be riparian associated species. In addition, we found Oregon salamanders (Ensatina eschscholtzi) were associated with upslope habitats. We suggest riparian management zones should be al least 75-100 m on each side of the stream and that management for upslope/and or old forest associates may be equally as important as for riparian species.

  5. Water relations of riparian plants from warm desert regions

    USGS Publications Warehouse

    Smith, S.D.; Devitt, Dale A.; Cleverly, James R.; Busch, David E.

    1998-01-01

    Riparian plants have been classified as 'drought avoiders' due to their access to an abundant subsurface water supply. Recent water-relations research that tracks water sources of riparian plants using the stable isotopes of water suggests that many plants of the riparian zone use ground water rather than stream water, and not all riparian plants are obligate phreatophytes (dependent on ground water as a moisture source) but may occasionally be dependent of unsaturated soil moisture sources. A more thorough understanding of riparian plant-water relations must include water-source dynamics and how those dynamics vary over both space and time. Many rivers in the desert Southwest have been invaded by the exotic shrub Tamarix ramosissima (saltcedar). Our studies of Tamarix invasion into habitats formerly dominated by native riparian forests of primarily Populus and Salix have shown that Tamarix successfully invades these habitats because of its (1) greater tolerance to water stress and salinity, (2) status as a facultative, rather than obligate, phreatophyte and, therefore, its ability to recover from droughts and periods of ground-water drawdown, and (3) superior regrowth after fire. Analysis of water- loss rates indicate that Tamarix-dominated stands can have extremely high evapotranspiration rates when water tables are high but not necessarily when water tables are lower. Tamarix has leaf-level transpiration rates that are comparable to native species, whereas sap-flow rates per unit sapwood area are higher than in natives, suggesting that Tamarix maintains higher leaf area than can natives, probably due to its greater water stress tolerance. Tamarix desiccates and salinizes floodplains, due to its salt exudation and high transpiration rates, and may also accelerate fire cycles, thus predisposing these ecosystems to further loss of native taxa. Riparian species on regulated rivers can be exposed to seasonal water stress due to depression of floodplain water tables

  6. Geologic map of the Bartlett Springs Fault Zone in the vicinity of Lake Pillsbury and adjacent areas of Mendocino, Lake, and Glenn Counties, California

    USGS Publications Warehouse

    Ohlin, Henry N.; McLaughlin, Robert J.; Moring, Barry C.; Sawyer, Thomas L.

    2010-01-01

    The Lake Pillsbury area lies in the eastern part of the northern California Coast Ranges, along the east side of the transform boundary between the Pacific and North American plates (fig. 1). The Bartlett Springs Fault Zone is a northwest-trending zone of faulting associated with this eastern part of the transform boundary. It is presently active, based on surface creep (Svarc and others, 2008), geomorphic expression, offset of Holocene units (Lienkaemper and Brown, 2009), and microseismicity (Bolt and Oakeshott, 1982; Dehlinger and Bolt, 1984; DePolo and Ohlin, 1984). Faults associated with the Bartlett Springs Fault Zone at Lake Pillsbury are steeply dipping and offset older low to steeply dipping faults separating folded and imbricated Mesozoic terranes of the Franciscan Complex and interleaved rocks of the Coast Range Ophiolite and Great Valley Sequence. Parts of this area were mapped in the late 1970s and 1980s by several investigators who were focused on structural relations in the Franciscan Complex (Lehman, 1978; Jordan, 1975; Layman, 1977; Etter, 1979). In the 1980s the U.S. Geological Survey (USGS) mapped a large part of the area as part of a mineral resource appraisal of two U.S. Forest Service Roadless areas. For evaluating mineral resource potential, the USGS mapping was published at a scale of 1:62,500 as a generalized geologic summary map without a topographic base (Ohlin and others, 1983; Ohlin and Spear, 1984). The previously unpublished mapping with topographic base is presented here at a scale of 1:30,000, compiled with other mapping in the vicinity of Lake Pillsbury. The mapping provides a geologic framework for ongoing investigations to evaluate potential earthquake hazards and structure of the Bartlett Springs Fault Zone. This geologic map includes part of Mendocino National Forest (the Elk Creek Roadless Area) in Mendocino, Glenn, and Lake Counties and is traversed by several U.S. Forest Service Routes, including M1 and M6 (fig. 2). The study

  7. Prescribed fires as ecological surrogates for wildfires: A stream and riparian perspective

    USGS Publications Warehouse

    Arkle, R.S.; Pilliod, D.S.

    2010-01-01

    Forest managers use prescribed fire to reduce wildfire risk and to provide resource benefits, yet little information is available on whether prescribed fires can function as ecological surrogates for wildfire in fire-prone landscapes. Information on impacts and benefits of this management tool on stream and riparian ecosystems is particularly lacking. We used a beyond-BACI (Before, After, Control, Impact) design to investigate the effects of a prescribed fire on a stream ecosystem and compared these findings to similar data collected after wildfire. For 3 years after prescribed fire treatment, we found no detectable changes in periphyton, macroinvertebrates, amphibians, fish, and riparian and stream habitats compared to data collected over the same time period in four unburned reference streams. Based on changes in fuels, plant and litter cover, and tree scorching, this prescribed fire was typical of those being implemented in ponderosa pine forests throughout the western U.S. However, we found that the extent and severity of riparian vegetation burned was substantially lower after prescribed fire compared to nearby wildfires. The early-season prescribed fire did not mimic the riparian or in-stream ecological effects observed following a nearby wildfire, even in catchments with burn extents similar to the prescribed fire. Little information exists on the effects of long-term fire exclusion from riparian forests, but a "prescribed fire regime" of repeatedly burning upland forests while excluding fire in adjacent riparian forests may eliminate an important natural disturbance from riparian and stream habitats.

  8. Responses to riparian restoration in the Spring Creek watershed, Central Pennsylvania

    USGS Publications Warehouse

    Carline, R.F.; Walsh, M.C.

    2007-01-01

    Riparian treatments, consisting of 3- to 4-m buffer strips, stream bank stabilization, and rock-lined stream crossings, were installed in two streams with livestock grazing to reduce sediment loading and stream bank erosion. Cedar Run and Slab Cabin Run, the treatment streams, and Spring Creek, an adjacent reference stream without riparian grazing, were monitored prior to (1991-1992) and 3-5 years after (2001-2003) riparian buffer installation to assess channel morphology, stream substrate composition, suspended sediments, and macroinvertebrate communities. Few changes were found in channel widths and depths, but channel-structuring flow events were rare in the drought period after restoration. Stream bank vegetation increased from 50% or less to 100% in nearly all formerly grazed riparian buffers. The proportion of fine sediments in stream substrates decreased in Cedar Run but not in Slab Cabin Run. After riparian treatments, suspended sediments during base flow and storm flow decreased 47-87% in both streams. Macroinvertebrate diversity did not improve after restoration in either treated stream. Relative to Spring Creek, macroinvertebrate densities increased in both treated streams by the end of the posttreatment sampling period. Despite drought conditions that may have altered physical and biological effects of riparian treatments, goals of the riparian restoration to minimize erosion and sedimentation were met. A relatively narrow grass buffer along 2.4 km of each stream was effective in improving water quality, stream substrates, and some biological metrics. ?? 2007 Society for Ecological Restoration International.

  9. Risk assessment of riparian plant invasions into protected areas.

    PubMed

    Foxcroft, Llewellyn C; Rouget, Mathieu; Richardson, David M

    2007-04-01

    Protected areas are becoming increasingly isolated. River corridors represent crucial links to the surrounding landscape but are also major conduits for invasion of alien species. We developed a framework to assess the risk that alien plants in watersheds adjacent to a protected area will invade the protected area along rivers. The framework combines species- and landscape-level approaches and has five key components: (1) definition of the geographical area of interest, (2) delineation of the domain into ecologically meaningful zones, (3) identification of the appropriate landscape units, (4) categorization of alien species and mapping of their distribution and abundance, and (5) definition of management options. The framework guides the determination of species distribution and abundance through successive, easily followed steps, providing the means for the assessment of areas of concern. We applied the framework to Kruger National Park (KNP) in South Africa. We recorded 231 invasive alien plant species (of which 79 were major invaders) in the domain. The KNP is facing increasing pressure from alien species in the upper regions of the drainage areas of neighboring watersheds. On the basis of the climatic modeling, we showed that most major riparian invaders have the ability to spread across the KNP should they be transported down the rivers. With this information, KNP managers can identify areas for proactive intervention, monitoring, and resource allocation. Even for a very large protected area such as the KNP, sustainable management of biodiversity will depend heavily on the response of land managers upstream managing alien plants. We suggest that this framework is applicable to plants and other passively dispersed species that invade protected areas situated at the end of a drainage basin.

  10. Geomorphic and hydrologic controls on riparian vegetation in the Grand Canyon, Arizona

    SciTech Connect

    Bechtel, D.A.; Stevens, L.E.; Kearsley, M.J.; Ayers, T.J. )

    1993-06-01

    Interactions between geomorphology and hydrology largely control the structure and composition of riparian vegetation in the Grand Canyon. Geologic structure, water table elevation, flooding and sediment deposition collectively create distinctive habitats required by major riparian assemblages in the dam-controlled Colorado River and its unregulated tributaries. Riparian assemblages in dominant geomorphic settings are associated with different combinations of substrata, inundation frequencies, and geomorphic features along this dam-regulated system. Data on recruitment, growth and water potential confirm that physical attributes of geomorphic zones are the causal force behind plant community structure. Alternative biotic hypotheses regarding community organization (e.g. competition, herbivory, dispersal) are discussed and dismissed.

  11. Assessing Risks of Shallow Riparian Groundwater Quality Near an Oil Sands Tailings Pond.

    PubMed

    Roy, J W; Bickerton, G; Frank, R A; Grapentine, L; Hewitt, L M

    2016-07-01

    The potential discharge of groundwater contaminated by oil sands process-affected water (OSPW) is a concern for aquatic ecosystems near tailings ponds. Groundwater in the area, but unaffected by OSPW, may contain similar compounds, complicating the assessment of potential ecological impacts. In this study, 177 shallow groundwater samples were collected from riparian areas along the Athabasca River and tributaries proximate to oil sands developments. For "pond-site" samples (71; adjacent to study tailings pond), Canadian aquatic life guidelines were exceeded for 11 of 20 assessed compounds. However, "non-pond" samples (54; not near any tailings pond) provided similar exceedances. Statistical analyses indicate that pond-site and non-pond samples were indistinguishable for all but seven parameters assessed, including salts, many trace metals, and fluorescence profiles of aromatic naphthenic acids (ANA). This suggests that, regarding the tested parameters, groundwater adjacent to the study tailings pond generally poses no greater ecological risk than other nearby groundwaters at this time. Multivariate analyses applied to the groundwater data set separated into 11 smaller zones support this conclusion, but show some variation between zones. Geological and potential OSPW influences could not be distinguished based on major ions and metals concentrations. However, similarities in indicator parameters, namely ANA, F, Mo, Se, and Na-Cl ratio, were noted between a small subset of samples from two pond-site zones and two OSPW samples and two shallow groundwater samples documented as likely OSPW affected. This indicator-based screening suggests that OSPW-affected groundwater may be reaching Athabasca River sediments at a few locations. PMID:26743232

  12. Phytoplankton and nutrient distributions in a front-eddy area adjacent to the coastal upwelling zone off Concepcion (Chile): implications for ecosystem productivity.

    NASA Astrophysics Data System (ADS)

    Morales, Carmen; Anabalón, Valeria; Hormazábal, Samuel; Cornejo, Marcela; Bento, Joaquim; Silva, Nelson

    2016-04-01

    The impact that sub-mesoscale (1-10 km) to mesocale (50-100 km) oceanographic variability has on plankton and nutrient distributions (horizontal and vertical) in the coastal upwelling and transition zones off Concepcion was the focus of this study. Satellite time-series data (wind, sea-surface temperature (SST), and altimetry) were used to understand the dynamic context of in situ data derived from a short-term front survey (3 d) during the upwelling period (3-6 February, 2014). The survey included two transects perpendicular to the coast, covering the shelf and shelf-break areas just north of Punta Lavapie, a main upwelling center (˜37° S). Wind and SST time-series data indicated that the survey was undertaken just after a moderate upwelling event (end of January) which lead to a relaxation phase during early February. A submesoscale thermal front was detected previous to and during the survey and results from an eddy tracking algorithm based on altimetry data indicated that this front (F1) was flanked on its oceanic side by an anticyclonic, mesoscale eddy (M1), which was ˜25 d old at the sampling time. M1 strengthened the thermal gradient of F1 by bringing warmer oceanic water nearer to the colder coastal upwelling zone. The distributions of hydrographic variables and nutrients in the water column (<300 m depth) also denoted these two features. Phytoplankton biomass (Chl-a) and diatom abundance were highest in the surface layer (<20 m depth) between the coast and F1, with primary maxima in the latter, whereas they were highest at the subsurface (20-40 m depth) towards M1 and associated with secondary maxima. The distribution of dominant diatoms in the top layer (<100 m depth) indicated that both coastal and oceanic species were aggregated at F1 and in M1. These results suggest that the front-eddy interaction creates a complex field of submesoscale processes in the top layer, including vertical nutrient injections and lateral stirring, which contributes to the

  13. Snowmelt induced hydrologic perturbations drive dynamic microbiological and geochemical behaviors across a shallow riparian aquifer

    NASA Astrophysics Data System (ADS)

    Danczak, Robert; Yabusaki, Steven; Williams, Kenneth; Fang, Yilin; Hobson, Chad; Wilkins, Michael

    2016-05-01

    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments.

  14. 2011 Los Alamos National Laboratory Riparian Inventory Results

    SciTech Connect

    Norris, Elizabeth J.; Hansen, Leslie A.; Hathcock, Charles D.; Keller, David C.; Zemlick, Catherine M.

    2012-03-29

    A total length of 36.7 kilometers of riparian habitat were inventoried within LANL boundaries between 2007 and 2011. The following canyons and lengths of riparian habitat were surveyed and inventoried between 2007 and 2011. Water Canyon (9,669 m), Los Alamos Canyon (7,131 m), Pajarito Canyon (6,009 m), Mortandad Canyon (3,110 m), Two-Mile Canyon (2,680 m), Sandia Canyon (2,181 m), Three-Mile Canyon (1,883 m), Canyon de Valle (1,835 m), Ancho Canyon (1,143 m), Canada del Buey (700 m), Sandia Canyon (221 m), DP Canyon (159 m) and Chaquehui Canyon (50 m). Effluent Canyon, Fence Canyon and Potrillo Canyon were surveyed but no areas of riparian habitat were found. Stretches of inventoried riparian habitat were classified for prioritization of treatment, if any was recommended. High priority sites included stretches of Mortandad Canyon, LA Canyon, Pajarito Canyon, Two-Mile Canyon, Sandia Canyon and Water Canyon. Recommended treatment for high priority sites includes placement of objects into the stream channel to encourage sediment deposition, elimination of channel incision, and to expand and slow water flow across the floodplain. Additional stretches were classified as lower priority, and, for other sites it was recommended that feral cattle and exotic plants be removed to aid in riparian habitat recovery. In June 2011 the Las Conchas Wildfire burned over 150,000 acres of land in the Jemez Mountains and surrounding areas. The watersheds above LA Canyon, Water Canyon and Pajarito Canyon were burned in the Las Conchas Wildfire and flooding and habitat alteration were observed in these canyon bottoms (Wright 2011). Post fire status of lower priority areas may change to higher priority for some of the sites surveyed prior to the Las Conchas Wildfire, due to changes in vegetation cover in the adjacent upland watershed.

  15. Influence of a riparian wetland on nitrate and herbicides exported from an agricultural field.

    PubMed

    Angier, Jonathan T; McCarty, Gregory W; Rice, Clifford P; Bialek, Krystyna

    2002-07-17

    Agrochemicals are a major source of nonpoint pollution. Forested corridors along stream channels (riparian zones) are thought to be potential sites for removal of agricultural contaminants from ground and surface waters. First-order riparian wetlands are reputed to be especially effective at groundwater remediation. The study site is a fairly typical (for eastern Maryland) small, first-order stream in an agricultural watershed. Preferential flow supplies most of the stream water within the riparian headwater wetland. This upstream area also contains the highest average stream N and pesticide loads in the entire first-order riparian system. Zones of active groundwater emergence onto the surface display high concentrations of nitrate throughout the soil profile and in the exfiltrating water, whereas inactive areas (where there is no visible upwelling) show rapid attenuation of nitrate with decreasing depths. Atrazine degradation products appear to penetrate more readily through the most active upwelling zones, and there is a correlation between zones of high nitrate and high atrazine metabolite levels. Deethylatrazine/atrazine ratios (DAR) seem to indicate that stream flow is dominated by ground water and that much of the ground water may have reached the stream via preferential flow. Remediative processes appear to be very complex, heterogeneous, and variable in these systems, so additional research is needed before effective formulation and application of riparian zone initiatives and guidelines can be accomplished.

  16. Characterization of particulate organic matter in the Lena River delta and adjacent nearshore zone, NE Siberia - Part 2: Lignin-derived phenol compositions

    NASA Astrophysics Data System (ADS)

    Winterfeld, M.; Goñi, M. A.; Just, J.; Hefter, J.; Mollenhauer, G.

    2015-04-01

    The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south-stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl : vanillyl (C / V) and syringyl : vanillyl (S / V) ratios are > 0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are > 0.16 and > 0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C / V and S / V ratios, and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (~ 12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad / AlV, S) in Lena Delta summer TSM (> 0.7 and > 0.5, respectively) and Buor Khaya Bay surface sediments (> 1.0 and > 0.9, respectively) suggest that the OM is highly degraded and Lena River

  17. Characterization of particulate organic matter in the Lena River Delta and adjacent nearshore zone, NE Siberia - Part 1: Lignin-derived phenol compositions

    NASA Astrophysics Data System (ADS)

    Winterfeld, M.; Goñi, M. A.; Just, J.; Hefter, J.; Mollenhauer, G.

    2014-10-01

    The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl:vanillyl (C/V) and syringyl:vanillyl (S/V) ratios are >0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are >0.16 and >0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C/V and S/V ratios and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (∼12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad/AlV, S) in Lena Delta summer TSM (>0.7 and >0.5, respectively) and Buor Khaya Bay surface sediments (>1.0 and >0.9, respectively) suggest that the OM is highly degraded and Lena River summer TSM could

  18. Nitrogen uptake and turnover in riparian woody vegetation.

    PubMed

    Chambers, Chris; Marshall, John D; Danehy, Robert J

    2004-06-01

    The nutrient balance of streams and adjacent riparian ecosystems may be modified by the elimination of anadromous fish runs and perhaps by forest fertilization. To better understand nitrogen (N) dynamics within stream and riparian ecosystems we fertilized two streams and their adjacent riparian corridors in central Idaho. On each stream two nitrogen doses were applied to a swathe approximately 35 m wide centered on the stream. The fertilizer N was enriched in 15N to 18 per thousand. This enrichment is light relative to many previous labeling studies, yet sufficient to yield a traceable signal in riparian and stream biota. This paper reports pre-treatment differences in delta15N and the first-year N response to fertilizer within the riparian woody plant community. Future papers will describe the transfer of allochthonous litter N to the stream and its subsequent processing by stream biota. Pre-treatment delta15N differed between the two creeks (P=0.0002), possibly due to residual salmon nitrogen in one of the creeks. Pre-treatment delta15N of current-year needles was enriched compared to leaf litter, which was in turn enriched compared to needles aged 4 years and older. We conclude that fractionation due to retranslocation occurs in at least two phases. The first phase, which optimizes allocation of N in younger needle age classes, is distinctly different from the second, which conserves N prior to abscission. The delta15N difference between creeks was eliminated by the fertilization (P=0.42). In the two dominant conifer species, Abies lasiocarpa and Picea engelmannii, most fertilizer N was found in the current-year foliage; little was found in older needles and none was detected in litter (P=0.53). The only N-fixing shrub species, Alnus incana, took up only a small amount of fertilizer N [mean percent N derived from fertilizer (%Ndff) 5.0+/-1.6% (SE)]. Far more fertilizer N was taken up by other deciduous shrubs (mean %Ndff=33.9+/-4.5%). Fertilizer N made up 25

  19. Characterizing Controls of Riparian Width for Mountain Streams in the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Polvi, L. E.; Wohl, E. E.

    2007-12-01

    High variability of mountain streams causes riparian width to vary greatly from changes in drainage, valley and channel characteristics. GIS- based models for predicting flood-prone width, valley bottoms, or riparian zones may not accurately reflect processes at the reach scale, therefore field verification and reach-specific studies are needed. Management of riparian areas often designates a generalized width, which may under- or over-estimate the true riparian width. This study examines correlations between potential control variables and riparian zone width in the Colorado Front Range. Results from this study will be used to predict the riparian zone as a proxy for flood-prone width in the semi-arid Colorado Front Range. We hypothesize that local controls interact with large- scale controls to determine floodplain processes. Large-scale controls identified are elevation, which reflects hydroclimatology and glacial history, gradient and drainage area. Local controls are entrenchment, the ratio of the valley width to channel width, connectedness, defined as the distance from the channel to valley edge, presence of colluvium, and vegetation type, affecting roughness during flooding and bank stability. We chose twenty reaches based on elevation, connectedness, gradient and drainage area using a GIS base map in anthropogenically undisturbed areas of the Colorado Front Range, which included the Cache la Poudre and North St. Vrain drainages. Riparian width was defined using a three-tiered approach: evidence of fluvial processes and presence of riparian vegetation, compared with the Q100 stage. A longitudinal and two valley and channel cross-section surveys were completed at each stream reach to determine valley and channel geometry and bed gradient. Preliminary results show significant positive correlations between drainage area, entrenchment, and connectedness and riparian width, and negative correlations between gradient and riparian width, supporting the hypothesis

  20. Development and Evaluation of a Riparian Buffer Mapping Tool

    USGS Publications Warehouse

    Milheim, Lesley E.; Claggett, Peter R.

    2008-01-01

    Land use and land cover within riparian areas greatly affect the conditions of adjacent water features. In particular, riparian forests provide many environmental benefits, including nutrient uptake, bank stabilization, steam shading, sediment trapping, aquatic and terrestrial habitat, and stream organic matter. In contrast, residential and commercial development and associated transportation infrastructure increase pollutant and nutrient loading and change the hydrologic characteristics of the landscape, thereby affecting both water quality and habitat. Restoring riparian areas is a popular and cost effective restoration technique to improve and protect water quality. Recognizing this, the Chesapeake Executive Council committed to restoring 10,000 miles of riparian forest buffers throughout the Chesapeake Bay watershed by the year 2010. In 2006, the Chesapeake Executive Council further committed to 'using the best available...tools to identify areas where retention and expansion of forests is most needed to protect water quality'. The Chesapeake Bay watershed encompasses 64,000 square miles, including portions of six States and Washington, D.C. Therefore, the interpretation of remotely sensed imagery provides the only effective technique for comprehensively evaluating riparian forest protection and restoration opportunities throughout the watershed. Although 30-meter-resolution land use and land cover data have proved useful on a regional scale, they have not been equally successful at providing the detail required for local-scale assessment of riparian area characteristics. Use of high-resolution imagery (HRI) provides sufficient detail for local-scale assessments, although at greater cost owing to the cost of the imagery and the skill and time required to process the data. To facilitate the use of HRI for monitoring the extent of riparian forest buffers, the U.S. Forest Service and the U.S. Geological Survey Eastern Geographic Science Center funded the

  1. Herbivore-induced "deshrubification" alters the biogeochemistry of subarctic riparian ecosystems

    NASA Astrophysics Data System (ADS)

    Smis, Adriaan; Ravolainen, Virve; Bråthen, Kari Anne; Ims, Rolf; Meire, Patrick; Struyf, Eric

    2013-04-01

    In the European subarctic, river valleys and other moist zones are dominated by tall shrub tundra, dominated by willows. Although climate warming is generally hypothesized to result in an expansion of this shrub zone, intensive reindeer husbandry in Finnmark (Northern Fennoscandia) during the last three decades seems to have resulted in a "deshrubification": riparian tall willow dominated shrub zones evolved to open meadows, dominated by grasses. These changes in land cover may have major biogeochemical consequences for both the terrestrial and aquatic environment. We investigated the relation between this "deshrubification" and the biogeochemical cycling of silicon (Si), nitrogen (N) and phosphorous (P), essential nutrients for aquatic primary production. This study was conducted along a climatic gradient from the moist and warm southwest towards the drier and colder northeast of Finnmark. Along the contrast of Finnmarks typical reindeer husbandry system, with intensively grazed summer pastures and extensively grazed spring/autumn pastures, we quantified the difference in vegetation composition and the associated differences in terrestrial pools of Si, N, P and soil organic carbon. Intensive reindeer grazing consistently excludes the presence of willow shrubs in the studied riparian zone and the transition from willow dominated tall shrub tundra towards open meadows dominated by grasses is associated with a clear silicification of the vegetation: all dominating grasses in the open meadow-state show 10 to 30 times higher Si concentrations compared to the dominating willow and forb species of the tall shrub vegetation, but also original tall shrub species show increased Si-concentrations under the intensive grazing regime. Silicon is a known defence component against herbivory, especially in grasses. Opposite, a transition to more N- and P-poor species occurs under intensive reindeer grazing: the continuum between tall willow dominated shrubs and open meadows is

  2. Effects of habitat disturbance from residential development on breeding bird communities in riparian corridors.

    PubMed

    Lussier, Suzanne M; Enser, Richard W; Dasilva, Sara N; Charpentier, Michael

    2006-09-01

    This study assessed the relationship among land use, riparian vegetation,and avian populations at two spatial scales. Our objective was to compare the vegetated habitat in riparian corridors with breeding bird guilds in eight Rhode Island subwatersheds along a range of increasing residential land use. Riparian habitats were characterized with fine-scale techniques (used field transects to measure riparian vegetation structure and plant species richness) at the reach spatial scale,and with coarse-scale landscape techniques (a Geographic Information System to document land-cover attributes) at the subwatershed scale. Bird surveys were conducted in the riparian zone,and the observed bird species were separated into guilds based on tolerance to human disturbance,habitat preference,foraging type, and diet preference. Bird guilds were correlated with riparian vegetation metrics,percent impervious surface,and percent residential land use,revealing patterns of breeding bird distribution. The number of intolerant species predominated below 12%residential development and 3% impervious surface,whereas tolerant species predominated above these levels.Habitat guilds of edge,forest, and wetland bird species correlated with riparian vegetation. This study showed that the application of avian guilds at both stream reach and subwatershed scales offers a comprehensive assessment of effects from disturbed habitat,but that the subwatershed scale is a more efficient method of evaluation for environmental management.

  3. Factors affecting songbird nest survival in riparian forests in a midwestern agricultural landscape

    USGS Publications Warehouse

    Peak, R.G.; Thompson, F. R.; Shaffer, T.L.

    2004-01-01

    We investigated factors affecting nest success of songbirds in riparian forest and buffers in northeastern Missouri. We used an information-theoretic approach to determine support for hypotheses concerning effects of nest-site, habitat-patch, edge, and temporal factors on nest success of songbirds in three narrow (55-95 m) and three wide (400-530 m) riparian forests with adjacent grassland-shrub buffer strips and in three narrow and three wide riparian forests without adjacent grassland-shrub buffer strips. We predicted that temporal effects would have the most support and that habitat-patch and edge effects would have little support, because nest predation would be great across all sites in the highly fragmented, predominantly agricultural landscape. Interval nest success was 0.404, 0.227, 0.070, and 0.186, respectively, for Gray Catbird (Dumetella carolinensis), Northern Cardinal (Cardinalis cardinalis), Indigo Bunting (Passerina cyanea), and forest interior species pooled (Acadian Flycatcher [Empidonax virescens], Wood Thrush [Hylocichla mustelina], Ovenbird [Seiurus aurocapillus], and Kentucky Warbler [Oporornis formosus]). The effect of nest stage on nest success had the most support; daily nest success for Gray Catbird and Indigo Bunting were lowest in the laying stage. We found strong support for greater nest success of Gray Catbird in riparian forests with adjacent buffer strips than in riparian forests without adjacent buffer strips. Patch width also occurred in the most-supported model for Gray Catbird, but with very limited support. The null model received the most support for Northern Cardinal. Riparian forests provided breeding habitat for area-sensitive forest species and grassland-shrub nesting species. Buffer strips provided additional breeding habitat for grassland-shrub nesting species. Interval nest success for Indigo Bunting and area-sensitive forest species pooled, however, fell well below the level that is likely necessary to balance juvenile

  4. Factors affecting songbird nest survival in riparian forests in a Midwestern agricultural landscape

    USGS Publications Warehouse

    Peak, R.G.; Thompson, F. R.; Shaffer, T.L.

    2004-01-01

    We investigated factors affecting nest success of songbirds in riparian forest and buffers in northeastern Missouri. We used an information-theoretic approach to determine support for hypotheses concerning effects of nest-site, habitat-patch, edge, and temporal factors on nest success of songbirds in three narrow (55DS95 m) and three wide (400DS530 m) riparian forests with adjacent grasslandDSshrub buffer strips and in three narrow and three wide riparian forests without adjacent grasslandDSshrub buffer strips. We predicted that temporal effects would have the most support and that habitat-patch and edge effects would have little support, because nest predation would be great across all sites in the highly fragmented, predominantly agricultural landscape. Interval nest success was 0.404, 0.227, 0.070, and 0.186, respectively, for Gray Catbird (Dumetella carolinensis), Northern Cardinal (Cardinalis cardinalis), Indigo Bunting (Passerina cyanea), and forest interior species pooled (Acadian Flycatcher [Empidonax virescens], Wood Thrush [Hylocichla mustelina], Ovenbird [Seiurus aurocapillus], and Kentucky Warbler [Oporornis formosus]). The effect of nest stage on nest success had the most support; daily nest success for Gray Catbird and Indigo Bunting were lowest in the laying stage. We found strong support for greater nest success of Gray Catbird in riparian forests with adjacent buffer strips than in riparian forests without adjacent buffer strips. Patch width also occurred in the most supported model for Gray Catbird, but with very limited support. The null model received the most support for Northern Cardinal. Riparian forests provided breeding habitat for areas sensitive forest species and grassland-shrub nesting species. Buffer strips provided additional breeding habitat for grassland-shrub nesting species. Interval nest success for Indigo Bunting and area-sensitive forest species pooled, however, fell well below the level that is likely necessary to balance

  5. Agricultural conservation planning framework: 2. Classification of riparian buffer design types with application to assess and map stream corridors.

    PubMed

    Tomer, M D; Boomer, K M B; Porter, S A; Gelder, B K; James, D E; McLellan, E

    2015-05-01

    A watershed's riparian corridor presents opportunities to stabilize streambanks, intercept runoff, and influence shallow groundwater with riparian buffers. This paper presents a system to classify these riparian opportunities and apply them toward riparian management planning in hydrologic unit code 12 watersheds. In two headwater watersheds from each of three landform regions found in Iowa and Illinois, high-resolution (3-m grid) digital elevation models were analyzed to identify spatial distributions of surface runoff contributions and zones with shallow water tables (SWTs) (within 1.5 m of the channel elevation) along the riparian corridors. Results were tabulated, and a cross classification was applied. Classes of buffers include those primarily placed to (i) trap runoff and sediment, (ii) influence shallow groundwater, (iii) address both runoff and shallow groundwater, and (iv) maintain/improve stream bank stability. Riparian buffers occupying about 2.5% of these six watersheds could effectively intercept runoff contributions from 81 to 94% of the watersheds' contributing areas. However, extents of riparian zones where a narrow buffer (<10 m wide) would adequately intercept runoff but where >25 m width of buffer vegetation could root to a SWT varied according to landform region ( < 0.10). Yet, these wide-SWT riparian zones were widespread and occupied 23 to 53% of the lengths of stream banks among the six watersheds. The wide-SWT setting provides opportunities to reduce dissolved nutrients (particularly NO-N) carried via groundwater. This riparian classification and mapping system is part of a ArcGIS toolbox and could provide a consistent basis to identify riparian management opportunities in Midwestern headwater catchments wherever high-resolution elevation data are available. PMID:26024257

  6. Riparian and in-stream controls on nutrient concentrations along a headwater forested stream

    NASA Astrophysics Data System (ADS)

    Bernal, S.; Lupon, A.; Ribot, M.; Sabater, F.; Martí, E.

    2014-07-01

    Headwater streams have a strong capacity to transform and retain nutrients, and thus, a longitudinal decrease in stream nutrient concentrations would be expected from in-stream nutrient removal alone. Yet, a number of other factors within the catchment, including biogeochemical processing within the riparian zone and export to streams, can contribute to stream nutrient concentration, which may overcome the effect of in-stream biogeochemical processing. To explore this idea, we analyzed the longitudinal patterns of stream and riparian groundwater concentrations for chloride (Cl-), nitrate (NO3-), ammonium (NH4+), and phosphate (PO43-) along a 3.7 km reach at an annual scale. The reach showed a gradual increase in stream and riparian width, riparian tree basal area, and abundance of riparian N2-fixing tree species. Concentrations of Cl- indicated a~strong hydrological connection at the riparian-stream edge. However, stream and riparian groundwater nutrient concentrations showed a moderate to null correlation, suggesting high biogeochemical processing at the riparian-stream edge and within the stream. A mass balance approach along the reach indicated that, on average, in-stream net nutrient uptake prevailed over release for NH4+ and PO43-, but not for NO3-. On an annual basis, in-stream processes contributed to change stream input fluxes by 11%, 26%, and 29% for NO3-, NH4+, and PO43-, respectively. Yet, longitudinal trends in concentration were not consistent with the prevailing in-stream biogeochem ical processes. During the riparian dormant period, stream concentration decreased along the reach for NO3-, but increased for NH4+ and PO43-. During the riparian vegetative period, NO3- and PO43- increased along the reach while NH4+ showed no clear pattern. These longitudinal trends were partially related to riparian forest features and groundwater inputs, especially for NO3- and PO43-. Our study suggests that even though in-stream biogeochemical

  7. Riparian forest buffers mitigate the effects of deforestation on fish assemblages in tropical headwater streams.

    PubMed

    Lorion, Christopher M; Kennedy, Brian P

    2009-03-01

    Riparian forest buffers may play a critical role in moderating the impacts of deforestation on tropical stream ecosystems, but very few studies have examined the ecological effects of riparian buffers in the tropics. To test the hypothesis that riparian forest buffers can reduce the impacts of deforestation on tropical stream biota, we sampled fish assemblages in lowland headwater streams in southeastern Costa Rica representing three different treatments: (1) forested reference stream reaches, (2) stream reaches adjacent to pasture with a riparian forest buffer averaging at least 15 m in width on each bank, and (3) stream reaches adjacent to pasture without a riparian forest buffer. Land cover upstream from the study reaches was dominated by forest at all of the sites, allowing us to isolate the reach-scale effects of the three study treatments. Fish density was significantly higher in pasture reaches than in forest and forest buffer reaches, mostly due to an increase in herbivore-detritivores, but fish biomass did not differ among reach types. Fish species richness was also higher in pasture reaches than in forested reference reaches, while forest buffer reaches were intermediate. Overall, the taxonomic and trophic structure of fish assemblages in forest and forest buffer reaches was very similar, while assemblages in pasture reaches were quite distinct. These patterns were persistent across three sampling periods during our 15-month study. Differences in stream ecosystem conditions between pasture reaches and forested sites, including higher stream temperatures, reduced fruit and seed inputs, and a trend toward increased periphyton abundance, appeared to favor fish species normally found in larger streams and facilitate a native invasion process. Forest buffer reaches, in contrast, had stream temperatures and allochthonous inputs more similar to forested streams. Our results illustrate the importance of riparian areas to stream ecosystem integrity in the tropics

  8. Riparian responses to extreme climate and land-use change scenarios.

    PubMed

    Fernandes, Maria Rosário; Segurado, Pedro; Jauch, Eduardo; Ferreira, Maria Teresa

    2016-11-01

    Climate change will induce alterations in the hydrological and landscape patterns with effects on riparian ecotones. In this study we assess the combined effect of an extreme climate and land-use change scenario on riparian woody structure and how this will translate into a future risk of riparian functionality loss. The study was conducted in the Tâmega catchment of the Douro basin. Boosted Regression Trees (BRTs) were used to model two riparian landscape indicators related with the degree of connectivity (Mean Width) and complexity (Area Weighted Mean Patch Fractal Dimension). Riparian data were extracted by planimetric analysis of high spatial-resolution Word Imagery Layer (ESRI). Hydrological, climatic and land-use variables were obtained from available datasets and generated with process-based modeling using current climate data (2008-2014), while also considering the high-end RCP8.5 climate-change and "Icarus" socio-economic scenarios for the 2046-2065 time slice. Our results show that hydrological and land-use changes strongly influence future projections of riparian connectivity and complexity, albeit to diverse degrees and with differing effects. A harsh reduction in average flows may impair riparian zones while an increase in extreme rain events may benefit connectivity by promoting hydrologic dynamics with the surrounding floodplains. The expected increase in broad-leaved woodlands and mixed forests may enhance the riparian galleries by reducing the agricultural pressure on the area in the vicinity of the river. According to our results, 63% of river segments in the Tâmega basin exhibited a moderate risk of functionality loss, 16% a high risk, and 21% no risk. Weaknesses and strengths of the method are highlighted and results are discussed based on a resilience perspective with regard to riparian ecosystems. PMID:27341115

  9. Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

    USGS Publications Warehouse

    Hagar, Joan C.; Li, Judith; Sobota, Janel; Jenkins, Stephanie

    2012-01-01

    Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

  10. Riparian responses to extreme climate and land-use change scenarios.

    PubMed

    Fernandes, Maria Rosário; Segurado, Pedro; Jauch, Eduardo; Ferreira, Maria Teresa

    2016-11-01

    Climate change will induce alterations in the hydrological and landscape patterns with effects on riparian ecotones. In this study we assess the combined effect of an extreme climate and land-use change scenario on riparian woody structure and how this will translate into a future risk of riparian functionality loss. The study was conducted in the Tâmega catchment of the Douro basin. Boosted Regression Trees (BRTs) were used to model two riparian landscape indicators related with the degree of connectivity (Mean Width) and complexity (Area Weighted Mean Patch Fractal Dimension). Riparian data were extracted by planimetric analysis of high spatial-resolution Word Imagery Layer (ESRI). Hydrological, climatic and land-use variables were obtained from available datasets and generated with process-based modeling using current climate data (2008-2014), while also considering the high-end RCP8.5 climate-change and "Icarus" socio-economic scenarios for the 2046-2065 time slice. Our results show that hydrological and land-use changes strongly influence future projections of riparian connectivity and complexity, albeit to diverse degrees and with differing effects. A harsh reduction in average flows may impair riparian zones while an increase in extreme rain events may benefit connectivity by promoting hydrologic dynamics with the surrounding floodplains. The expected increase in broad-leaved woodlands and mixed forests may enhance the riparian galleries by reducing the agricultural pressure on the area in the vicinity of the river. According to our results, 63% of river segments in the Tâmega basin exhibited a moderate risk of functionality loss, 16% a high risk, and 21% no risk. Weaknesses and strengths of the method are highlighted and results are discussed based on a resilience perspective with regard to riparian ecosystems.

  11. Modeling riparian soil nitrogen removal based on a modified SWAT model coupled with remote sensing data

    NASA Astrophysics Data System (ADS)

    Wang, Xuelei; Yang, Shengtian; Mannaerts, Chris M.; Zeng, Hongjuan; Zheng, Donghai

    2010-11-01

    Riparian zone, as the interlaced zone between land and water, plays an important role in society, landscape and environmental quality. Riparian ecosystems have critical impacts on controlling the non-point source pollution (NPSP) and maintaining the health of aquatic ecosystems, especially on nitrogen (N) removal. The processes that affect N removal in riparian ecological system mainly include soil nitrous gas emission, plant uptake and sediment retention, of which nitrous gas release by soil denitrification is one of the most important functions for riparian system. Therefore, it's critical to build an N removal model including soil denitrification, nitrification and ammonium volatilization to evaluate the riparian ecological function and management practice. In this study, the Soil and Water Assessment Tool (SWAT) was extended with algorithms from a simple soil denitrification model and remote sensing data to enhance the model performance with regard to predicting soil N removal in the Guanting reservoir riparian catchment. The N removal model is based on chemical and physical relationships that govern soil heat, moisture and nitrogen movement. Processes considered include denitrification, nitrification and ammonia (NH3) volatilization. SPOT-5 and Landsat5-TM satellite data were used to interpret the spatial land surface information and derive model parameters. Results of laboratory-scale anaerobic incubation experiment were applied to estimate the soil denitrification model parameters for the different soil types. In an in situ field-scale experiment conducted to calibrate and validate models and an indirect method was used to test simulated N removal load in the Guanting reservoir riparian catchment. Results showed that the process-based model performed well and produced sound simulation results for the riparian reservoir catchment, with the coefficient of determination (R2) between the simulated and observed values being 0.71.

  12. Modeling riparian soil nitrogen removal based on a modified SWAT model coupled with remote sensing data

    NASA Astrophysics Data System (ADS)

    Wang, Xuelei; Yang, Shengtian; Mannaerts, Chris M.; Zeng, Hongjuan; Zheng, Donghai

    2009-09-01

    Riparian zone, as the interlaced zone between land and water, plays an important role in society, landscape and environmental quality. Riparian ecosystems have critical impacts on controlling the non-point source pollution (NPSP) and maintaining the health of aquatic ecosystems, especially on nitrogen (N) removal. The processes that affect N removal in riparian ecological system mainly include soil nitrous gas emission, plant uptake and sediment retention, of which nitrous gas release by soil denitrification is one of the most important functions for riparian system. Therefore, it's critical to build an N removal model including soil denitrification, nitrification and ammonium volatilization to evaluate the riparian ecological function and management practice. In this study, the Soil and Water Assessment Tool (SWAT) was extended with algorithms from a simple soil denitrification model and remote sensing data to enhance the model performance with regard to predicting soil N removal in the Guanting reservoir riparian catchment. The N removal model is based on chemical and physical relationships that govern soil heat, moisture and nitrogen movement. Processes considered include denitrification, nitrification and ammonia (NH3) volatilization. SPOT-5 and Landsat5-TM satellite data were used to interpret the spatial land surface information and derive model parameters. Results of laboratory-scale anaerobic incubation experiment were applied to estimate the soil denitrification model parameters for the different soil types. In an in situ field-scale experiment conducted to calibrate and validate models and an indirect method was used to test simulated N removal load in the Guanting reservoir riparian catchment. Results showed that the process-based model performed well and produced sound simulation results for the riparian reservoir catchment, with the coefficient of determination (R2) between the simulated and observed values being 0.71.

  13. Effects of stream flow intermittency on riparian vegetation of a semiarid region river (San Pedro River, Arizona)

    USGS Publications Warehouse

    Stromberg, J.C.; Bagstad, K.J.; Leenhouts, J.M.; Lite, S.J.; Makings, E.

    2005-01-01

    functional groups are abundant at perennial-flow sites when viewing the ecosystem at broader spatial and temporal scales: mesic riparian perennials are common in the floodplain zone adjacent to the river channel and late-summer hydric and mesic annuals are periodically abundant after large floods. Copyright ?? 2005 John Wiley & Sons, Ltd.

  14. Responses of riparian reptile communities to damming and urbanization

    USGS Publications Warehouse

    Hunt, Stephanie D.; Guzy, Jacquelyn C.; Price, Steven J.; Halstead, Brian J.; Eskew, Evan A.; Dorcas, Michael E.

    2013-01-01

    Various anthropogenic pressures, including habitat loss, threaten reptile populations worldwide. Riparian zones are critical habitat for many reptile species, but these habitats are also frequently modified by anthropogenic activities. Our study investigated the effects of two riparian habitat modifications-damming and urbanization-on overall and species-specific reptile occupancy patterns. We used time-constrained search techniques to compile encounter histories for 28 reptile species at 21 different sites along the Broad and Pacolet Rivers of South Carolina. Using a hierarchical Bayesian analysis, we modeled reptile occupancy responses to a site's distance upstream from dam, distance downstream from dam, and percent urban land use. The mean occupancy response by the reptile community indicated that reptile occupancy and species richness were maximized when sites were farther upstream from dams. Species-specific occupancy estimates showed a similar trend of lower occupancy immediately upstream from dams. Although the mean occupancy response of the reptile community was positively related to distance downstream from dams, the occupancy response to distance downstream varied among species. Percent urban land use had little effect on the occupancy response of the reptile community or individual species. Our results indicate that the conditions of impoundments and subsequent degradation of the riparian zones upstream from dams may not provide suitable habitat for a number of reptile species.

  15. Germination timing and rate of locally collected western wheatgrass and smooth brome grass: the role of collection site and light sensitivity along a riparian corridor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ecological integrity of riparian areas is reduced by biological plant invaders like smooth brome grass (Bromus inermis). Smooth brome actively invades recently disturbed riparian zones by its high seed production and fast seedling establishment. Restoring native perennial grasses to these regio...

  16. Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico.

    PubMed

    Nagler, Pamela L; Glenn, Edward P; Hinojosa-Huerta, Osvel; Zamora, Francisco; Howard, Keith

    2008-09-01

    Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000 ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1 m yr(-1) and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4 x 10(8)m(3)yr(-1), about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of

  17. Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico

    USGS Publications Warehouse

    Nagler, P.L.; Glenn, E.P.; Hinojosa-Huerta, O.; Zamora, F.; Howard, K. J.

    2008-01-01

    Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000 ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1 m yr-1 and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4??108 m3 yr-1, about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of the

  18. Remote sensing approach to map riparian vegetation of the Colorado River Ecosystem, Grand Canyon area, Arizona

    NASA Astrophysics Data System (ADS)

    Nguyen, U.; Glenn, E.; Nagler, P. L.; Sankey, J. B.

    2015-12-01

    Riparian zones in the southwestern U.S. are usually a mosaic of vegetation types at varying states of succession in response to past floods or droughts. Human impacts also affect riparian vegetation patterns. Human- induced changes include introduction of exotic species, diversion of water for human use, channelization of the river to protect property, and other land use changes that can lead to deterioration of the riparian ecosystem. This study explored the use of remote sensing to map an iconic stretch of the Colorado River in the Grand Canyon National Park, Arizona. The pre-dam riparian zone in the Grand Canyon was affected by annual floods from spring run-off from the watersheds of Green River, the Colorado River and the San Juan River. A pixel-based vegetation map of the riparian zone in the Grand Canyon, Arizona, was produced from high-resolution aerial imagery. The map was calibrated and validated with ground survey data. A seven-step image processing and classification procedure was developed based on a suite of vegetation indices and classification subroutines available in ENVI Image Processing and Analysis software. The result was a quantitative species level vegetation map that could be more accurate than the qualitative, polygon-based maps presently used on the Lower Colorado River. The dominant woody species in the Grand Canyon are now saltcedar, arrowweed and mesquite, reflecting stress-tolerant forms adapted to alternated flow regimes associated with the river regulation.

  19. Integrated riparian evaluation guide: Intermountain region

    SciTech Connect

    Not Available

    1992-03-01

    Riparian areas consist of riparian ecosystems, aquatic ecosystems, and wetlands. They may be associated with lakes, reservoirs, estuaries, potholes, marshes, springs, bogs, wet meadows, and intermittent or perennial streams where free and unbound water is available. Though riparian areas constitute only a fraction of the total land area, they are more productive in terms of both plant and animal species diversity and biomass per unit area than the remainder of the land base. The guide provides an integrated approach for: Stratifying and classifying riparian areas according to their natural inherent characteristics, and their respective existing or conditions; Data collection; Evaluation of riparian areas; Future development and linkage of a riparian data base; and Preparation of a written narrative to interpret the data and suggest management applications.

  20. Influence of riparian and watershed alterations on sandbars in a Great Plains river

    USGS Publications Warehouse

    Fischer, Jeffrey M.; Paukert, Craig P.; Daniels, M.L.

    2014-01-01

    Anthropogenic alterations have caused sandbar habitats in rivers and the biota dependent on them to decline. Restoring large river sandbars may be needed as these habitats are important components of river ecosystems and provide essential habitat to terrestrial and aquatic organisms. We quantified factors within the riparian zone of the Kansas River, USA, and within its tributaries that influenced sandbar size and density using aerial photographs and land use/land cover (LULC) data. We developed, a priori, 16 linear regression models focused on LULC at the local, adjacent upstream river bend, and the segment (18–44 km upstream) scales and used an information theoretic approach to determine what alterations best predicted the size and density of sandbars. Variation in sandbar density was best explained by the LULC within contributing tributaries at the segment scale, which indicated reduced sandbar density with increased forest cover within tributary watersheds. Similarly, LULC within contributing tributary watersheds at the segment scale best explained variation in sandbar size. These models indicated that sandbar size increased with agriculture and forest and decreased with urban cover within tributary watersheds. Our findings suggest that sediment supply and delivery from upstream tributary watersheds may be influential on sandbars within the Kansas River and that preserving natural grassland and reducing woody encroachment within tributary watersheds in Great Plains rivers may help improve sediment delivery to help restore natural river function.

  1. Linking channel hydrology with riparian wetland accretion in tidal rivers

    USGS Publications Warehouse

    Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.

    2014-01-01

    The hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood, yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the non-tidal through oligohaline portion of two coastal plain rivers in Maryland, U.S.A., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a one year period using artificial marker horizons, channel hydrology was measured over a one month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the non-tidal sites (mean and standard deviation = 8 ± 8 mm yr-1), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr-1), low at the midstream TFFW (12 ± 9 mm yr-1), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr-1). Channel maximum flood and ebb velocity was 2-fold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: the oligohaline zone's SSC was more than double the tidal freshwater zone's, and was greater than historical SSC at the non-tidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. Overall sediment accretion was higher in the embayed river likely due to a single storm discharge and associated sedimentation.

  2. Linking channel hydrology with riparian wetland accretion in tidal rivers

    NASA Astrophysics Data System (ADS)

    Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.

    2014-01-01

    hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the nontidal through oligohaline portion of two coastal plain rivers in Maryland, U.S., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a 1 year period using artificial marker horizons, channel hydrology was measured over a 1 month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the nontidal sites (mean and standard deviation = 8 ± 8 mm yr-1), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr-1), low at the midstream TFFW (12 ± 9 mm yr-1), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr-1). Channel maximum flood and ebb velocity was twofold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: The oligohaline zone's SSC was more than double the tidal freshwater zone's and was greater than historical SSC at the nontidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. High sediment accretion at the upstream TFFW was likely due to high river discharge following a hurricane.

  3. Riparian control of stream-water chemistry: Implications for hydrochemical basin models

    USGS Publications Warehouse

    Hooper, R.P.; Aulenbach, Brent T.; Burns, Douglas A.; McDonnell, J.; Freer, J.; Kendall, C.; Beven, K.

    1998-01-01

    End-member mixing analysis has been used to determine the hydrological structure for basin hydrochemical models at several catchments. Implicit in this use is the assumption that controlling end members have been identified, and that these end members represent distinct landscape locations. At the Panola Mountain Research Watershed, the choice of controlling end members was supported when a large change in the calcium and sulphate concentration of one of the end members was reflected in the stream water. More extensive sampling of groundwater and soil water indicated, however, that the geographic extent of the contributing end members was limited to the riparian zone. Hillslope solutions were chemically distinct from the riparian solutions and did not appear to make a large contribution to streamflow. The dominant control of the riparian zone on stream-water chemistry suggests that hydrological flow paths cannot be inferred from stream-water chemical dynamics.

  4. Groundwater management institutions to protect riparian habitat

    NASA Astrophysics Data System (ADS)

    Orr, Patricia; Colby, Bonnie

    2004-12-01

    Groundwater pumping affects riparian habitat when it causes the water table to drop beyond the reach of riparian plants. Riparian habitat provides services that are not directly traded in markets, as is the case with many environmental amenities. There is no direct market where one may buy or sell the mix of services provided by a riparian corridor. The objective of this article is to review groundwater management mechanisms and assess their strengths and weaknesses for preserving the ecological integrity of riparian areas threatened by groundwater pumping. Policy instruments available to those concerned with the effects of groundwater pumping on riparian areas fall into three broad categories: (1) command and control (CAC), (2) incentive-based economic instruments, and (3) cooperative/suasive strategies. The case of the San Pedro River illustrates multiple and overlapping strategies applied in an ongoing attempt to reverse accumulating damage to a riparian ecosystem. Policy makers in the United States can choose among a broad menu of policy options to protect riparian habitat from groundwater pumping. They can capitalize on the clarity of command-and-control strategies, the flexibility and less obtrusive nature of incentive-based economic strategies, and the benefits that collaborative efforts can bring in the form of mutual consideration. While collaborative problem solving and market-based instruments are important policy tools, experience indicates that a well-formulated regulatory structure to limit regional groundwater pumping is an essential component of an effective riparian protection strategy.

  5. The soil bacterial communities of South African fynbos riparian ecosystems invaded by Australian Acacia species.

    PubMed

    Slabbert, Etienne; Jacobs, Shayne Martin; Jacobs, Karin

    2014-01-01

    Riparian ecosystem along rivers and streams are characterised by lateral and longitudinal ecological gradients and, as a result, harbour unique biodiversity. Riparian ecosystems in the fynbos of the Western Cape, South Africa, are characterised by seasonal dynamics, with summer droughts followed by high flows during winter. The unique hydrology and geomorphology of riparian ecosystems play an important role in shaping these ecosystems. The riparian vegetation in the Western Cape has, however, largely been degraded due to the invasion of non-indigenous plants, in particular Acacia mearnsii, A. saligna and A. dealbata. This study investigated the effect of hydrology and invasion on the bacterial communities associated with fynbos riparian ecosystems. Bacterial communities were characterised with automated ribosomal intergenic spacer analysis (ARISA) and 454 16S rDNA pyrosequencing. Chemical and physical properties of soil within sites were also determined and correlated with community data. Sectioning across the lateral zones revealed significant differences in community composition, and the specific bacterial taxa influenced. Results also showed that the bacterial community structure could be linked to Acacia invasion. The presence of invasive Acacia was correlated with specific bacterial phyla. However, high similarity between cleared and pristine sites suggests that the effect of Acacia on the soil bacterial community structure may not be permanent. This study demonstrates how soil bacterial communities are influenced by hydrological gradients associated with riparian ecosystems and the impact of Acacia invasion on these communities. PMID:24475145

  6. The soil bacterial communities of South African fynbos riparian ecosystems invaded by Australian Acacia species.

    PubMed

    Slabbert, Etienne; Jacobs, Shayne Martin; Jacobs, Karin

    2014-01-01

    Riparian ecosystem along rivers and streams are characterised by lateral and longitudinal ecological gradients and, as a result, harbour unique biodiversity. Riparian ecosystems in the fynbos of the Western Cape, South Africa, are characterised by seasonal dynamics, with summer droughts followed by high flows during winter. The unique hydrology and geomorphology of riparian ecosystems play an important role in shaping these ecosystems. The riparian vegetation in the Western Cape has, however, largely been degraded due to the invasion of non-indigenous plants, in particular Acacia mearnsii, A. saligna and A. dealbata. This study investigated the effect of hydrology and invasion on the bacterial communities associated with fynbos riparian ecosystems. Bacterial communities were characterised with automated ribosomal intergenic spacer analysis (ARISA) and 454 16S rDNA pyrosequencing. Chemical and physical properties of soil within sites were also determined and correlated with community data. Sectioning across the lateral zones revealed significant differences in community composition, and the specific bacterial taxa influenced. Results also showed that the bacterial community structure could be linked to Acacia invasion. The presence of invasive Acacia was correlated with specific bacterial phyla. However, high similarity between cleared and pristine sites suggests that the effect of Acacia on the soil bacterial community structure may not be permanent. This study demonstrates how soil bacterial communities are influenced by hydrological gradients associated with riparian ecosystems and the impact of Acacia invasion on these communities.

  7. The Soil Bacterial Communities of South African Fynbos Riparian Ecosystems Invaded by Australian Acacia Species

    PubMed Central

    Slabbert, Etienne; Jacobs, Shayne Martin; Jacobs, Karin

    2014-01-01

    Riparian ecosystem along rivers and streams are characterised by lateral and longitudinal ecological gradients and, as a result, harbour unique biodiversity. Riparian ecosystems in the fynbos of the Western Cape, South Africa, are characterised by seasonal dynamics, with summer droughts followed by high flows during winter. The unique hydrology and geomorphology of riparian ecosystems play an important role in shaping these ecosystems. The riparian vegetation in the Western Cape has, however, largely been degraded due to the invasion of non-indigenous plants, in particular Acacia mearnsii, A. saligna and A. dealbata. This study investigated the effect of hydrology and invasion on the bacterial communities associated with fynbos riparian ecosystems. Bacterial communities were characterised with automated ribosomal intergenic spacer analysis (ARISA) and 454 16S rDNA pyrosequencing. Chemical and physical properties of soil within sites were also determined and correlated with community data. Sectioning across the lateral zones revealed significant differences in community composition, and the specific bacterial taxa influenced. Results also showed that the bacterial community structure could be linked to Acacia invasion. The presence of invasive Acacia was correlated with specific bacterial phyla. However, high similarity between cleared and pristine sites suggests that the effect of Acacia on the soil bacterial community structure may not be permanent. This study demonstrates how soil bacterial communities are influenced by hydrological gradients associated with riparian ecosystems and the impact of Acacia invasion on these communities. PMID:24475145

  8. Bioavailability and diagenetic state of dissolved organic matter in riparian groundwater

    NASA Astrophysics Data System (ADS)

    Peter, Simone; Shen, Yuan; Kaiser, Karl; Benner, Ronald; Durisch-Kaiser, Edith

    2012-12-01

    Riparian groundwater can exhibit considerable patchiness in the concentration and reactivity of dissolved organic matter (DOM), which ultimately shapes subsurface biogeochemical transformations. Free and combined amino acids are bioavailable constituents of DOM, and their concentration and composition can provide valuable information about the diagenetic state of DOM. Based on riparian groundwater samples and relevant DOM end-member samples, we adapted the amino-acid-based marine DOM degradation index (DI) to groundwater. The groundwater DI was applied to evaluate the spatial and temporal variability in the bioavailability and diagenetic state of riparian DOM in a restored and a channelized section of the River Thur, Switzerland. Among different indicators for DOM diagenetic state (total hydrolysable amino acid concentrations, C-normalized yields, and the contribution of nonprotein amino acids), the groundwater DI correlated best with the activity of the enzyme leucine-aminopeptidase and bacterial secondary production in riparian groundwater. The "freshest" DOM was consistently found in the channel and during high-flow conditions in the groundwater of the restored riparian section and was spatially constrained to a zone inhabited by a dense willow population. The use of amino acid data and the newly developed DI for DOM in groundwater is a promising approach for characterizing the spatial and temporal dynamics of DOM reactivity and diagenesis within riparian groundwater.

  9. Multi-zone furnace system

    SciTech Connect

    Orbeck, G.A.

    1986-05-06

    A multi-zone furnace is described which consists of: a furnace chamber having at least one heat zone and at least one zone adjacent to the heat zone and disposed along the length of the furnace chamber; the heat zone having a hearth at a level different from the hearth level of the adjacent zone; a walking beam conveyor disposed in the furnace chamber and operative in a short stroke mode to convey a product along the hearth of the heat zone, and in a long stroke mode to convey a product from the heat zone to the adjacent zone.

  10. Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems

    USGS Publications Warehouse

    Jacobs, Shayne M.; Bechtold, J.S.; Biggs, Harry C.; Grimm, N. B.; McClain, M.E.; Naiman, R.J.; Perakis, Steven S.; Pinay, G.; Scholes, M.C.

    2007-01-01

    This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact nutrient fluxes between riparian, upland and aquatic environments. Our review shows that strong environmental drivers such as fire and herbivory enhance nitrogen, phosphorus and sediment transport to lower slope positions by shaping vegetative patterns. These vectors differ significantly from other arid and semiarid ecosystems, and from mesic ecosystems where the impact of fire and herbivory are less pronounced and less predictable. Also unique is the presence of sodic soils in certain hillslopes, which substantially alters hydrological flowpaths and may act as a trap where nitrogen is immobilized while sediment and phosphorus transport is enhanced. Nutrients and sediments are also deposited in the riparian zone during seasonal, intermittent floods while, during the dry season, subsurface movement of water from the stream into riparian soils and vegetation further enrich riparian zones with nutrients. As is found in mesic ecosystems, nutrients are immobilized in semiarid riparian corridors through microbial and plant uptake, whereas dissimilatory processes such as denitrification may be important where labile nitrogen and carbon are in adequate supply and physical conditions are suitablea??such as in seeps, wallows created by animals, ephemeral wetlands and stream edges. Interaction between temporal hydrologic connectivity and spatial heterogeneity are disrupted by disturbances such as large floods and extended droughts, which may convert certain riparian patches from sinks to sources for nitrogen and phosphorus. In the face of increasing anthropogenic pressure, the scientific challenges are to provide a basic

  11. Fire and Grazing Influences on Rates of Riparian Woody Plant Expansion along Grassland Streams

    PubMed Central

    Veach, Allison M.; Dodds, Walter K.; Skibbe, Adam

    2014-01-01

    Grasslands are threatened globally due to the expansion of woody plants. The few remaining headwater streams within tallgrass prairies are becoming more like typical forested streams due to rapid conversion of riparian zones from grassy to wooded. Forestation can alter stream hydrology and biogeochemistry. We estimated the rate of riparian woody plant expansion within a 30 m buffer zone surrounding the stream bed across whole watersheds at Konza Prairie Biological Station over 25 years from aerial photographs. Watersheds varied with respect to experimentally-controlled fire and bison grazing. Fire frequency, presence or absence of grazing bison, and the historical presence of woody vegetation prior to the study time period (a proxy for proximity of propagule sources) were used as independent variables to predict the rate of riparian woody plant expansion between 1985 and 2010. Water yield was estimated across these years for a subset of watersheds. Riparian woody encroachment rates increased as burning became less frequent than every two years. However, a higher fire frequency (1–2 years) did not reverse riparian woody encroachment regardless of whether woody vegetation was present or not before burning regimes were initiated. Although riparian woody vegetation cover increased over time, annual total precipitation and average annual temperature were variable. So, water yield over 4 watersheds under differing burn frequencies was quite variable and with no statistically significant detected temporal trends. Overall, burning regimes with a frequency of every 1–2 years will slow the conversion of tallgrass prairie stream ecosystems to forested ones, yet over long time periods, riparian woody plant encroachment may not be prevented by fire alone, regardless of fire frequency. PMID:25192194

  12. Fire and grazing influences on rates of riparian woody plant expansion along grassland streams.

    PubMed

    Veach, Allison M; Dodds, Walter K; Skibbe, Adam

    2014-01-01

    Grasslands are threatened globally due to the expansion of woody plants. The few remaining headwater streams within tallgrass prairies are becoming more like typical forested streams due to rapid conversion of riparian zones from grassy to wooded. Forestation can alter stream hydrology and biogeochemistry. We estimated the rate of riparian woody plant expansion within a 30 m buffer zone surrounding the stream bed across whole watersheds at Konza Prairie Biological Station over 25 years from aerial photographs. Watersheds varied with respect to experimentally-controlled fire and bison grazing. Fire frequency, presence or absence of grazing bison, and the historical presence of woody vegetation prior to the study time period (a proxy for proximity of propagule sources) were used as independent variables to predict the rate of riparian woody plant expansion between 1985 and 2010. Water yield was estimated across these years for a subset of watersheds. Riparian woody encroachment rates increased as burning became less frequent than every two years. However, a higher fire frequency (1-2 years) did not reverse riparian woody encroachment regardless of whether woody vegetation was present or not before burning regimes were initiated. Although riparian woody vegetation cover increased over time, annual total precipitation and average annual temperature were variable. So, water yield over 4 watersheds under differing burn frequencies was quite variable and with no statistically significant detected temporal trends. Overall, burning regimes with a frequency of every 1-2 years will slow the conversion of tallgrass prairie stream ecosystems to forested ones, yet over long time periods, riparian woody plant encroachment may not be prevented by fire alone, regardless of fire frequency.

  13. Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

    PubMed

    Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

    2010-09-01

    River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

  14. Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.

    PubMed

    Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

    2010-09-01

    River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and

  15. Riparian vegetation structure under desertification scenarios

    NASA Astrophysics Data System (ADS)

    Rosário Fernandes, M.; Segurado, Pedro; Jauch, Eduardo; Ferreira, M. Teresa

    2015-04-01

    Riparian areas are responsible for many ecological and ecosystems services, including the filtering function, that are considered crucial to the preservation of water quality and social benefits. The main goal of this study is to quantify and understand the riparian variability under desertification scenario(s) and identify the optimal riparian indicators for water scarcity and droughts (WS&D), henceforth improving river basin management. This study was performed in the Iberian Tâmega basin, using riparian woody patches, mapped by visual interpretation on Google Earth imagery, along 130 Sampling Units of 250 m long river stretches. Eight riparian structural indicators, related with lateral dimension, weighted area and shape complexity of riparian patches were calculated using Patch Analyst extension for ArcGis 10. A set of 29 hydrological, climatic, and hydrogeomorphological variables were computed, by a water modelling system (MOHID), using monthly meteorological data between 2008 and 2014. Land-use classes were also calculated, in a 250m-buffer surrounding each sampling unit, using a classification based system on Corine Land Cover. Boosted Regression Trees identified Mean-width (MW) as the optimal riparian indicator for water scarcity and drought, followed by the Weighted Class Area (WCA) (classification accuracy =0.79 and 0.69 respectively). Average Flow and Strahler number were consistently selected, by all boosted models, as the most important explanatory variables. However, a combined effect of hidrogeomorphology and land-use can explain the high variability found in the riparian width mainly in Tâmega tributaries. Riparian patches are larger towards Tâmega river mouth although with lower shape complexity, probably related with more continuous and almost monospecific stands. Climatic, hydrological and land use scenarios, singly and combined, were used to quantify the riparian variability responding to these changes, and to assess the loss of riparian

  16. Sediment dynamics in restored riparian forest with different widths and agricultural surroundings

    NASA Astrophysics Data System (ADS)

    Stucchi Boschi, Raquel; Simões da Silva, Laura; Ribeiro Rodrigues, Ricardo; Cooper, Miguel

    2016-04-01

    The riparian forests are essential to maintaining the quality of water resources, aquifer recharge and biodiversity. Due to the ecological services provided by riparian forests, these areas are considered by the law as Permanent Preservation Areas, being mandatory maintenance and restoration. However, the obligation of restoration and the extent of the Permanent Preservation Areas as defined by the Brazilian Forest Code, based on water body width, elucidates the lack of accurate scientific data on the influence of the size of the riparian forest in maintaining their ecological functions, particularly regarding the retention of sediments. Studies that evaluate the ideal width of riparian forests to guarantee their ecological functions are scarce and not conclusive, especially when we consider newly restored forests, located in agricultural areas. In this study, we investigate the dynamics of erosion and sedimentation in restored riparian forests with different widths situated in agricultural areas. The two study areas are located in a Semideciduous Tropical Forest inserted in sugarcane landscapes of São Paulo state, Brazil. The installed plots had 60 and 100 m in length and the riparian forest has a width of 15, 30 and 50 m. The characteristics of the sediments inside the plots were evaluated by detailed morphological and micromorphological studies as well as physical characterization. The dynamics of deposition and the amount of deposited sediments have been assessed with graded metal stakes partially buried inside the plots. The intensity, frequency and distribution of rainfall, as well as the occurrence of extreme events, have been evaluated by data collected from rain gauges installed in the areas. We expect that smaller widths are not able to retain sediments originated from the adjacent sugarcane areas. We also believe that extreme events are responsible for generating most of the sediments. The results will be important to support the discussion about an

  17. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  18. DECISION TOOL FOR RIPARIAN ECOSYSTEM MANAGMENT IN THE MID-ATLANTIC HIGHLANDS

    EPA Science Inventory

    In the Canaan Valley Highlands of the Mid-Atlantic, riparian zone restoration has been identified as a critical watershed management practice not only for the ecosystem services provided but also for the potential socioeconomic growth from environmental investment and job creatio...

  19. Vertical distribution of total carbon, nitrogen and phosphorus in riparian soils of Walnut Creek, southern Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Palmer, J.A.; Bettis, E. Arthur; Jacobson, P.; Schultz, R.C.; Isenhart, T.M.

    2009-01-01

    Subsurface lithology plays an important role in many riparian zone processes, but few studies have examined how sediment nutrient concentrations vary with depth. In this study, we evaluated concentrations of nutrients (N, C and P) with depth in a riparian zone of the glaciated Midwest. A total of 146 sediment samples were collected from 24 cores that extended to a maximum depth of 3.6??m at eight sites in the riparian zone of Walnut Creek. Subsurface deposits were predominantly silt loam, becoming coarser and more variable with depth. Nitrogen and carbon content ranged from < 0.01 to 0.42% and < 0.01 to 7.08%, respectively, and exhibited a strong trend of decreasing nutrient content with depth. In contrast, P concentrations averaged 574??mg/kg and did not vary systematically. Systematic variations in texture and nutrient content with depth largely corresponded to stratigraphic differentiation among the Camp Creek, Roberts Creek and Gunder members of the regionally recognized Holocene-age DeForest Formation. Variations in subsurface nutrient content were not found to be significantly related to present land cover, but land cover may have influenced nutrient content at the time of original sediment accumulation. Subsurface lithology and stratigraphy should be considered an important component in riparian zone studies where nutrient losses to streams via streambank erosion or groundwater discharge are assessed. ?? 2009 Elsevier B.V. All rights reserved.

  20. Water table fluctuations under three riparian land covers, Iowa (USA)

    USGS Publications Warehouse

    Schilling, K.E.

    2007-01-01

    Water table depth is known to play an important role in nitrogen cycling in riparian zones, but little detailed monitoring of water table fluctuations has been reported. In this study, results of high-resolution water table monitoring under three common riparian land covers (forest, cool season grass, corn) were analysed to gain a better understanding of the relation of vegetation cover to water table depth. Three riparian wells located at the Neal Smith National Wildlife Refuge in Jasper County, Iowa, were instrumented with data loggers to record hourly water table behaviour from July to December 2004. Water table depth under the forest showed a diurnal pattern of rising and falling water levels, whereas the grass and corn exhibited a stepped pattern of greater drawdown during the day and less drainage at night. Clear daytime and night-time water table signals were related to daily plant water demands and lateral groundwater flow. Using two estimates of specific yield, hourly and daily ET rates were estimated to be higher under the forest cover than the grass and corn, with peak ET rates in July ranging from 5.02 to 6.32 mm day-1 for forest and from 1.81 to 4.13 mm day-1 for corn and grass. Following plant senescence in October, water table declines were associated with lateral flow to Walnut Creek. The results from this study suggest that consideration should be given to monitoring water table behaviour more frequently to capture daily and seasonal patterns related to riparian vegetation type. Copyright ?? 2007 John Wiley & Sons, Ltd.

  1. Riparian buffer transpiration and watershed scale impacts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forested riparian buffers are prevalent throughout the Southeastern Coastal Plain Region of the United States (US). Because they make up a significant portion of the regional landscape, transpiration within these riparian buffers is believed to have an important impact on the hydrologic budget of r...

  2. RESEARCH NEEDS IN RIPARIAN BUFFER RESTORATION

    EPA Science Inventory

    Riparian buffer restorations are used as management tools to produce favorable water quality impacts; moreover, the basis for riparian buffers as an instrument of water quality restoration rests on a relatively firm foundation. However, the extent to which buffers can restore rip...

  3. Influence of planting grass filter strips on the structure and function of riparian habitats of agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grass filter strips are strips of cool or warm season grasses planted adjacent to agricultural streams to reduce nutrient, pesticide, and sediment input. This conservation practice is the most frequently planted riparian buffer type in the United States. Previous studies have not evaluated how gra...

  4. Effects of climate-induced increases in summer drought on riparian plant species: a meta-analysis

    PubMed Central

    Garssen, Annemarie G; Verhoeven, Jos T A; Soons, Merel B

    2014-01-01

    , surface water permanence and certain plant traits, especially plasticity in rooting depth, were mentioned most frequently as factors determining species responses. Very few studies mentioned hydrological thresholds, such as critical values for ground- and/or surface water levels, and so far these results have proved difficult to generalise. 6. Our meta-analysis has shown that the projected increase in the duration and intensity of drought periods, especially intense droughts lasting more than 30 days, can be expected to narrow the riparian wetland zone with typical hydric species and accelerate riparian wetland species losses in the near future. This may require extra efforts in terms of management and restoration of species-rich riparian areas. PMID:26180267

  5. Riparian vegetation in South-western Europe: drivers of change across space and time (Invited)

    NASA Astrophysics Data System (ADS)

    Aguiar, F. C.; Ferriera, M.

    2010-12-01

    Riparian ecosystems of Mediterranean Europe have been largely disturbed for millennia due to human-driven alterations. Land-use, deforestation, water diversion and river regulation have been the major causes of change of riparian and freshwater ecosystems. Riparian vegetation in this region has particular features due to a large climatic and environmental variation; from the climatic harshness and the flash-flow hydrological regime of southern rivers to high-altitude permanent rivers of the north regions. Riparia is a fundamental element of the Mediterranean landscape by a number of ecological values, and economic and societal benefits, and they are usually seen as “linear oasis” embedded in the complex landscape matrix. We face a huge challenge in understanding the distribution trends of the riparian species assemblages in those diverse biogeographic regions and the varying effects of the multi-scaled drivers of change. I will review the main studies that have explored the patterns of variation of riparian plant assemblages across space and time in South-Western Europe, including its longitudinal and lateral dimension. Structural community features and plant functional traits, that can be described and quantified, are ecological expressions of both natural and human disturbances, and comparatively less understood than floral composition patterns, and many studies suggest that they are more reactive to disturbance. Linkages of taxonomic and functional trait variation will also be addressed, focusing in the influence of environment at various scale levels. Effects of human disturbances, particularly the alien plant invasions and the losses of biodiversity and connectivity will be tackled. These studies provided evidence of shifts in species composition and in structural complexity, as well as in individual and community responses to wetting and drying due to regulation and to physical disturbances of riverbanks. The intensive agriculture in adjacent lands is a

  6. Grande Ronde Model Watershed Project; Dark Canyon Riparian Exclosure, Completion Report 2002.

    SciTech Connect

    Kuck, Todd

    2003-03-01

    The Baker Field Office, Vale District Bureau of Land Management (BLM) submitted a project proposal for funding in 2002 through the Grande Ronde Model Watershed Program (GRMWP). The project consisted of constructing two riparian exclosures to prevent livestock grazing in the riparian areas of Dark Canyon and Meadow Creek. The BLM completed the NEPA documentation and supplied the fencing materials. Funding from BPA through the GRMWP was used to complete the construction of the two exclosures. This project was completed in the fall of 2002. The project area is located in Union County, Oregon on BLM managed land adjacent to Dark Canyon and Meadow Creek, T. 3. S., R. 35 E., Section 24 and 25. Section 24 is along Dark Canyon Creek and section 25 is along Meadow Creek. Approximately 0.4 miles of stream would be protected from grazing with the construction of the two exclosures. A two person crew was hired to construct a four-strand barbed wire fence. The fence enclosed the riparian area on both sides of each creek so that no grazing would occur within the riparian area on BLM managed land. Total fence length is approximately 1.25 miles. Materials consisted of metal fence posts, barbed wire, rockjacks, fence stays, and 2 x 4's. The fence was constructed in the fall of 2002. The riparian area is effectively excluded from livestock grazing at this time. The construction of the exclosures should enhance riparian vegetation, increase bank stability, and improve riparian and in-stream habitat by exclusion of livestock in the riparian areas. Monitoring will ensure that the exclosures continues to be effective. Annual monitoring will include photo-points and compliance checks during the grazing season by BLM personnel. The BLM will submit a monitoring report, which includes the results of the annual monitoring, to the GRMWP in years 2005 and 2007. The exclosures do cross the creeks so maintenance may be needed on occasion, especially after high flow events in the creeks. Material

  7. Effects of drought on birds and riparian vegetation in the Colorado River Delta, Mexico

    USGS Publications Warehouse

    Hinojosa-Huerta, Osvel; Nagler, Pamela L.; Carrillo-Guererro, Yamilett K.; Glenn, Edward P.

    2013-01-01

    The riparian corridor in the delta of the Colorado River in Mexico supports internationally important bird habitat. The vegetation is maintained by surface flows from the U.S. and Mexico and by a high, non-saline aquifer into which the dominant phreatophytic shrubs and trees are rooted. We studied the effects of a regional drought on riparian vegetation and avian abundance and diversity from 2002 to 2007, during which time surface flows were markedly reduced compared to the period from 1995 to 2002. Reduced surface flows led to a reduction in native tree cover but an increase in shrub cover, mostly due to an increase in Tamarix spp., an introduced halophytic shrub, and a reduction in Populus fremontii and Salix gooddingii trees. However, overall vegetation cover was unchanged at about 70%. Overall bird density and diversity were also unchanged, but riparian-obligate species tended to decrease in abundance, and generalist species increased. Although reduction in surface flows reduced habitat value and negatively impacted riparian-obligate bird species, portions of the riparian zone exhibited resilience. Surface flows are required to reduce soil salt levels and germinate new cohorts of native trees, but the main source of water supporting this ecosystem is the aquifer, derived from underflows from irrigated fields in the U.S. and Mexico. The long-term prospects for delta riparian habitats are uncertain due to expected reduced flows of river water from climate change, and land use practices that will reduce underflows to the riparian aquifer and increase salinity levels. Active restoration programs would be needed if these habitats are to be preserved for the future.

  8. Riparian vegetation and its water use during 1995 along the Mojave River, Southern California

    USGS Publications Warehouse

    Lines, Gregory C.; Bilhorn, Thomas W.

    1996-01-01

    The extent and areal density of riparian vegetation, including both phreatophytes and hydrophytes, were mapped along the 100-mile main stem of the Mojave River during 1995. Mapping was aided by vertical false-color infrared and low-level oblique photographs. However, positive identification of plant species and plant physiological stress required field examination. The consumptive use of ground water and surface water by different areal densities of riparian plant communities along the main stem of the Mojave River was estimated using water-use data from a select group of studies in the southwestern United States. In the Alto subarea of the Mojave basin management area, consumptive water use during 1995 by riparian vegetation was estimated to be about 5,000 acre-feet upstream from the Lower Narrows and about 6,000 acre-feet downstream in the transition zone. In the Centro and Baja subareas, consumptive water use was estimated to be about 3,000 acre-feet and 2,000 acre-feet, respectively, during 1995. Consumptive water use by riparian vegetation in the Afton area, downstream from the Baja subarea, was estimated to be about 600 acre-feet during 1995. Consumptive water use by riparian vegetation during 1995 is considered representative of "normal" hydrologic conditions along the Mojave River. Barring major changes in the areal extent and density of riparian vegetation, the 1995 consumptive-use estimates should be fairly representative of riparian vegetation water use during most years. Annual consumptive use, however, could vary from the 1995 estimates as much as plus or minus 50 percent because of extreme hydrologic conditions (periods of high water table following extraordinarily large runoff in the Mojave River or periods of extended drought).

  9. Downstream Effects of Diversion Dams on Riparian Vegetation Communities in the Routt National Forest, Colorado

    NASA Astrophysics Data System (ADS)

    Caskey, S. T.; Wohl, E. E.; Dwire, K. A.; Merritt, D. M.; Schnackenberg, L.

    2012-12-01

    The relationship between riparian vegetation and changes in fluvial processes as a response to flow diversion is not well understood. Water extraction affects the hydrologic flow regime (i.e., magnitude, duration, and frequency of flows) reducing peak and base-flows, which could negatively impact riparian vegetation. Vegetation communities are temporally and spatially variable and are strongly interrelated with alluvial landforms and hydrograph variability. This research compares riparian community characteristics on diverted and undiverted pool-riffle channels and low gradient valleys to examine changes associated with flow diversion in the Routt National Forest (RNF). The RNF is the only under-appropriated area in Colorado, making future water extraction proposals likely. Many small extraction canals siphon water from small, headwater streams in the RNF, but the site-specific or cumulative effects of these diversions on riverine ecosystems have not been investigated. Systematic investigation is necessary, however, to determine whether existing flow diversions have influenced riparian communities and, if so, which communities are most sensitive to diversions. A total of 36 sites were sampled with five channel cross sections established per site, extending into the riparian zone at distance of two times the active channel width, and vegetation was sampled using the line-point intercept method. Preliminary results suggest a shift in vegetation communities from typical riparian species composition to more upland vegetation. The relative sensitivity of these responses are different depending on valley type; low- gradient, unconfined areas are less tolerant of diversion than steeper, confined reaches. Additionally, when stratified by plant assemblage, Salix abundance is significantly reduced downstream of diversion. The results of this study contribute to the collective understanding of mountain headwater riparian vegetation community response to changes in flow

  10. Viscosity changes of riparian water controls diurnal fluctuations of stream-flow and DOC concentration

    NASA Astrophysics Data System (ADS)

    Schwab, Michael; Klaus, Julian; Pfister, Laurent; Weiler, Markus

    2015-04-01

    Diurnal fluctuations in stream-flow are commonly explained as being triggered by the daily evapotranspiration cycle in the riparian zone, leading to stream flow minima in the afternoon. While this trigger effect must necessarily be constrained by the extent of the growing season of vegetation, we here show evidence of daily stream flow maxima in the afternoon in a small headwater stream during the dormant season. We hypothesize that the afternoon maxima in stream flow are induced by viscosity changes of riparian water that is caused by diurnal temperature variations of the near surface groundwater in the riparian zone. The patterns were observed in the Weierbach headwater catchment in Luxembourg. The catchment is covering an area of 0.45 km2, is entirely covered by forest and is dominated by a schistous substratum. DOC concentration at the outlet of the catchment was measured with the field deployable UV-Vis spectrometer spectro::lyser (scan Messtechnik GmbH) with a high frequency of 15 minutes over several months. Discharge was measured with an ISCO 4120 Flow Logger. During the growing season, stream flow shows a frequently observed diurnal pattern with discharge minima in the afternoon. During the dormant season, a long dry period with daily air temperature amplitudes of around 10 ° C occurred in March and April 2014, with discharge maxima in the afternoon. The daily air temperature amplitude led to diurnal variations in the water temperature of the upper 10 cm of the riparian zone. Higher riparian water temperatures cause a decrease in water viscosity and according to the Hagen-Poiseuille equation, the volumetric flow rate is inversely proportional to viscosity. Based on the Hagen-Poiseuille equation and the viscosity changes of water, we calculated higher flow rates of near surface groundwater through the riparian zone into the stream in the afternoon which explains the stream flow maxima in the afternoon. With the start of the growing season, the viscosity

  11. Management of riparian habitat for mammals, birds, reptiles, and amphibians. Appendix C

    USGS Publications Warehouse

    Knutson, M.G.; Ribic, C.

    1999-01-01

    Melinda Knutson (USGS Upper Midwest Environmental Sciences Center) and Christine Ribic (USGS Wisconsin Cooperative Wildlife Research Unit) contributed to a recent report published by the USDA Natural Resources Conservation Service. The report summarizes a workshop held 8 December 1999 in Chicago, IL. Highlights of the report include resources and land management recommendations for riparian zones in the Midwest. The full report will soon be available at the USDA NRCS Wildlife Habitat Management Institute website: http://www.ms.nrcs.usda.gov/whmi/habitat.htm Knutson, M., and C. Ribic. 2000. Management of riparian habitat for mammals, birds, reptiles, and amphibians. Pages 22-24, Appendix C in W. Hohman, ed. NRCS Management and Restoration of Midwestern Riparian Systems Workshop Report. USDA Natural Resources Conservation Service, Chicago, IL.

  12. Recovery times of riparian vegetation

    NASA Astrophysics Data System (ADS)

    Vesipa, R.; Camporeale, C.; Ridolfi, L.

    2016-04-01

    Riparian vegetation is a key element in a number of processes that determine the ecogeomorphological features of the river landscape. Depending on the river water stage fluctuations, vegetation biomass randomly switches between growth and degradation phases and exhibits relevant temporal variations. A full understanding of vegetation dynamics is therefore only possible if the hydrological stochastic forcing is considered. In this vein, we focus on the recovery time of vegetation, namely the typical time taken by vegetation to recover a well-developed state starting from a low biomass value (induced, for instance, by an intense flood). The analytical expression of the plot-dependent recovery time is given, the role of hydrological and biological parameters is discussed, and the impact of river-induced randomness is highlighted. Finally, the effect of man-induced hydrological changes (e.g., river damming or climate changes) is explored.

  13. Pesticide and Nitrate-N Behavior in Groundwater Within a Riparian Wetland

    NASA Astrophysics Data System (ADS)

    Rice, C. P.; Bialek, K.; Angier, J. T.; McCarty, G. W.

    2002-05-01

    Information regarding the behavior and fate of agrochemicals in groundwater within riparian ecosystems is essential in order to assess the overall function of riparian systems at contaminant removal. This study included analysis of pesticides and nutrients in groundwater from a first-order riparian wetland that borders a conventionally farmed cornfield. Vertical depth profiles of groundwater were analyzed for agricultural chemicals. Samples were obtained from piezometers nested at various depths in different locations throughout the riparian wetland. Some of the nests were in areas with little or no visible groundwater seepage to the surface, others were placed in zones of active groundwater emergence (upwelling) onto the land surface (within zones of continuous surface saturation). In those profiles where upwelling was low, there was a clear demarcation in nitrate-N and oxygen contents at depth (between 135 and 175 cm) within the piezometer nests. This same horizon also coincided with the region where atrazine and atrazine degradate (desethyl- and desisopropyl-atrazine) concentrations substantially diminished. Another herbicide, metolachlor, and degradates (metolachlor ethane sulfonic acid and metolachlor oxanilic acid), showed only a slight reduction in concentrations over this zone and maintained a fairly uniform concentration over the vertical profile. Vertical depth profiles in areas where upwelling was high did not show significant variations in herbicide residues; e.g., the concentrations throughout the profile were similar to the levels measured at the deepest zone within the underlying aquifer. Processes leading to these differences were preferential degradation and sorption. This spatial disparity was reflected in the surface water, with implications for the overall contaminant-mitigating properties of the riparian system.

  14. Recovery times of riparian vegetation

    NASA Astrophysics Data System (ADS)

    Vesipa, Riccardo; Camporeale, Carlo; Ridolfi, Luca

    2016-04-01

    Riparian vegetation is a key element in a number of processes that determine the eco-geomorphological features of the river landscape. Depending on the river water stage fluctuations, vegetation biomass randomly switches between growth and decay phases, and its biomass exhibits relevant temporal variations. A full understanding of vegetation dynamics is therefore only possible if the hydrological stochastic forcing is considered. In this vein, we focus on the recovery time of vegetation, namely the typical time taken by vegetation to recover a health state starting from a low biomass value (induced, for instance, by an intense flood). The minimalistic stochastic modeling approach is used for describing vegetation dynamics (i.e., the noise-driven alternation of growth and decay phases). The recovery time of biomass is then evaluated according to the theory of the mean first passage time in systems driven by dichotomous noise. The effect of the main hydrological and biological parameters on the vegetation recovery was studied, and the dynamics along the riparian transect was described in details. The effect of climate change and human interventions (e.g., river damming) was also investigated. We found that: (i) the oscillations of the river stage delay the recovery process (up to one order of magnitude, with respect to undisturbed conditions); (ii) hydrological/biological alterations (due to climate change, damming, exotic species invasion) modify the timescales of the recovery. The result provided can be a useful tool for the management of the river. They open the way to the estimation of: (i) the recovery time of vegetation after devastating floods, clear cutting or fires and; (ii) the timescale of the vegetation response to hydrological and biological alterations.

  15. The use of phytometers for evaluating restoration effects on riparian soil fertility.

    PubMed

    Dietrich, Anna L; Lind, Lovisa; Nilsson, Christer; Jansson, Roland

    2014-11-01

    The ecological restoration of streams in Sweden has become increasingly important to counteract effects of past timber floating. In this study, we focused on the effect on riparian soil properties after returning coarse sediment (cobbles and boulders) to the channel and reconnecting riparian with in-stream habitats. Restoration increases habitat availability for riparian plants, but its effects on soil quality are unknown. We also analyzed whether the restoration effect differs with variation in climate and stream size. We used standardized plant species to measure the performance of a grass ( L.) and a forb ( L.) in soils sampled in the riparian zones of channelized and restored streams and rivers. Furthermore, we analyzed the mass fractions of carbon (C) and nitrogen (N) along with the proportions of the stable isotopes C and N in the soil, as well as its grain size composition. We found a positive effect of restoration on biomass of phytometers grown in riparian soils from small streams, indicating that restoration enhanced the soil properties favoring plant performance. We suggest that changed flooding with more frequent but less severe floods and slower flows, enhancing retention, could explain the observed patterns. This positive effect suggests that it may be advantageous to initiate restoration efforts in small streams, which make up the highest proportion of the stream network in a catchment. Restoration responses in headwater streams may then be transmitted downstream to facilitate recovery of restored larger rivers. If the larger rivers were restored first, a slower reaction would be expected. PMID:25602208

  16. The use of phytometers for evaluating restoration effects on riparian soil fertility.

    PubMed

    Dietrich, Anna L; Lind, Lovisa; Nilsson, Christer; Jansson, Roland

    2014-11-01

    The ecological restoration of streams in Sweden has become increasingly important to counteract effects of past timber floating. In this study, we focused on the effect on riparian soil properties after returning coarse sediment (cobbles and boulders) to the channel and reconnecting riparian with in-stream habitats. Restoration increases habitat availability for riparian plants, but its effects on soil quality are unknown. We also analyzed whether the restoration effect differs with variation in climate and stream size. We used standardized plant species to measure the performance of a grass ( L.) and a forb ( L.) in soils sampled in the riparian zones of channelized and restored streams and rivers. Furthermore, we analyzed the mass fractions of carbon (C) and nitrogen (N) along with the proportions of the stable isotopes C and N in the soil, as well as its grain size composition. We found a positive effect of restoration on biomass of phytometers grown in riparian soils from small streams, indicating that restoration enhanced the soil properties favoring plant performance. We suggest that changed flooding with more frequent but less severe floods and slower flows, enhancing retention, could explain the observed patterns. This positive effect suggests that it may be advantageous to initiate restoration efforts in small streams, which make up the highest proportion of the stream network in a catchment. Restoration responses in headwater streams may then be transmitted downstream to facilitate recovery of restored larger rivers. If the larger rivers were restored first, a slower reaction would be expected.

  17. RIPGIS-NET: a GIS tool for riparian groundwater evapotranspiration in MODFLOW.

    PubMed

    Ajami, Hoori; Maddock, Thomas; Meixner, Thomas; Hogan, James F; Guertin, D Phillip

    2012-01-01

    RIPGIS-NET, an Environmental System Research Institute (ESRI's) ArcGIS 9.2/9.3 custom application, was developed to derive parameters and visualize results of spatially explicit riparian groundwater evapotranspiration (ETg), evapotranspiration from saturated zone, in groundwater flow models for ecohydrology, riparian ecosystem management, and stream restoration. Specifically RIPGIS-NET works with riparian evapotranspiration (RIP-ET), a modeling package that works with the MODFLOW groundwater flow model. RIP-ET improves ETg simulations by using a set of eco-physiologically based ETg curves for plant functional subgroups (PFSGs), and separates ground evaporation and plant transpiration processes from the water table. The RIPGIS-NET program was developed in Visual Basic 2005, .NET framework 2.0, and runs in ArcMap 9.2 and 9.3 applications. RIPGIS-NET, a pre- and post-processor for RIP-ET, incorporates spatial variability of riparian vegetation and land surface elevation into ETg estimation in MODFLOW groundwater models. RIPGIS-NET derives RIP-ET input parameters including PFSG evapotranspiration curve parameters, fractional coverage areas of each PFSG in a MODFLOW cell, and average surface elevation per riparian vegetation polygon using a digital elevation model. RIPGIS-NET also provides visualization tools for modelers to create head maps, depth to water table (DTWT) maps, and plot DTWT for a PFSG in a polygon in the Geographic Information System based on MODFLOW simulation results.

  18. Understanding Riparian Ecosystem Function: Linking Biogeochemistry and Hydrology at Multiple Scales

    NASA Astrophysics Data System (ADS)

    Schade, J. D.; Grimm, N. B.; Lewis, D. B.; Villinski, J.; Welter, J. R.; Conklin, M.; Huth, A. K.

    2002-12-01

    The influence of riparian zones on the chemistry of ground and surface waters is highly dependent on the direction and strength of hydrologic exchange with stream and uplands. Here we use studies from two desert streams to illustrate how a detailed understanding of hydrology and biogeochemistry at multiple scales is necessary to unravel riparian zone influences on nutrient retention. At the reach scale (< 1 km), we have consistently found differences in both form and concentration of dissolved nutrients in subsystems arrayed laterally from stream to riparian terraces, and inter-reach differences in this lateral water chemistry pattern. These differences result from variation in process rates within subsystems and hydrologic exchange among them, making interpretation of water chemistry patterns difficult in the absence of detailed hydrologic information. Furthermore, estimates of nitrogen removal by plant uptake and denitrification, based on results of a Br and N-15 injection experiment, depend on assumptions of direction and magnitude of hydrologic exchange. Such a coarse-grained analysis provides valuable information on stream-riparian interactions but lacks sufficient hydrologic detail. At a stream-segment or watershed scale (10-100 km), tributaries and patterns of regional groundwater flow become important determinants of riparian function. The interaction between spatial and temporal variation in both N supply (including tributary flow and groundwater inputs) and N loss (particularly plant uptake and denitrification) dictates basin-scale N retention. The proportion of water entering and exiting catchments from overland flow and shallow and deep groundwater strongly influences how much of that water passes through riparian soils, which constrains the reach-scale role of the riparian zone in regulating water and nutrient fluxes from watersheds. Specific mechanisms of retention, including the role of vegetation, are easier to measure at subreach scales (< 100 m

  19. Time for recovery of riparian plants in restored northern Swedish streams: a chronosequence study.

    PubMed

    Hasselquist, Maher; Nilsson, Christer; Häxltén, Joakim; Jørgensen, Dolly; Lind, Lovisa; Polvi, Lina E

    2015-07-01

    A lack of ecological responses in stream restoration projects has been prevalent throughout recent literature with many studies reporting insufficient time for recovery. We assessed the relative importance of time, site variables, and landscape setting for understanding how plant species richness and understory productivity recover over time in riparian zones of northern Swedish streams. We used a space-for-time substitution consisting of 13 stream reaches restored 5-25 years ago, as well as five unrestored channelized reference reaches. We inventoried the riparian zone for all vascular plant species along 60-m study reaches and quantified cover and biomass in plots. We found that while species richness increased with time, understory biomass decreased. Forbs made up the majority of the species added, while the biomass of graminoids decreased the most over time, suggesting that the reduced dominance of graminoids favored less productive forbs. Species richness and density patterns could be attributed to dispersal limitation, with anemochorous species being more associated with time after restoration than hydrochorous, zoochorous, or vegetatively reproducing species. Using multiple linear regression, we found that time along with riparian slope and riparian buffer width (e.g., distance to logging activities) explained the most variability in species richness, but that variability in total understory biomass was explained primarily by time. The plant community composition of restored reaches differed from that of channelized references, but the difference did not increase over time. Rather, different time categories had different successional trajectories that seemed to converge on a unique climax community for that time period. Given our results, timelines for achieving species richness objectives should be extended to 25 years or longer if recovery is defined as a saturation of the accumulation of species over time. Other recommendations include making riparian

  20. Time for recovery of riparian plants in restored northern Swedish streams: a chronosequence study.

    PubMed

    Hasselquist, Maher; Nilsson, Christer; Häxltén, Joakim; Jørgensen, Dolly; Lind, Lovisa; Polvi, Lina E

    2015-07-01

    A lack of ecological responses in stream restoration projects has been prevalent throughout recent literature with many studies reporting insufficient time for recovery. We assessed the relative importance of time, site variables, and landscape setting for understanding how plant species richness and understory productivity recover over time in riparian zones of northern Swedish streams. We used a space-for-time substitution consisting of 13 stream reaches restored 5-25 years ago, as well as five unrestored channelized reference reaches. We inventoried the riparian zone for all vascular plant species along 60-m study reaches and quantified cover and biomass in plots. We found that while species richness increased with time, understory biomass decreased. Forbs made up the majority of the species added, while the biomass of graminoids decreased the most over time, suggesting that the reduced dominance of graminoids favored less productive forbs. Species richness and density patterns could be attributed to dispersal limitation, with anemochorous species being more associated with time after restoration than hydrochorous, zoochorous, or vegetatively reproducing species. Using multiple linear regression, we found that time along with riparian slope and riparian buffer width (e.g., distance to logging activities) explained the most variability in species richness, but that variability in total understory biomass was explained primarily by time. The plant community composition of restored reaches differed from that of channelized references, but the difference did not increase over time. Rather, different time categories had different successional trajectories that seemed to converge on a unique climax community for that time period. Given our results, timelines for achieving species richness objectives should be extended to 25 years or longer if recovery is defined as a saturation of the accumulation of species over time. Other recommendations include making riparian

  1. Do riparian reserves support dung beetle biodiversity and ecosystem services in oil palm-dominated tropical landscapes?

    PubMed

    Gray, Claudia L; Slade, Eleanor M; Mann, Darren J; Lewis, Owen T

    2014-04-01

    Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest-dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm-dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the

  2. Linking CZO, LTER, and NEON- Putting Biology into the Critical Zone

    NASA Astrophysics Data System (ADS)

    McDowell, W. H.

    2014-12-01

    With the advent of the Critical Zone Observatory Network, new opportunities are emerging to link the geological and ecological aspects of environmental science. Interactions between the CZO Network and the 30-year old Long-Term Ecological Research (LTER) Network can provide the opportunity to interpret long-term ecological research in the context of the geologic forces that have shaped both the form and function of the landscape. Using four examples from the Luquillo Mountains in tropical Puerto Rico, I highlight the ways in which ecological patterns and processes are driven by the underlying geologic template. The distribution of stream biota in the Luquillo Mountains is striking, with predatory fish below large geomorphic breaks; above these waterfalls, fish are absent, and shrimp dominate the biota. The critical zone thus structures aquatic communities. A second example is provided by the role of soil texture and structure in driving rates of greenhouse gas production. In the moderately well drained soils of the Luquillo Mountains, water-filled pore space is a key driver of methane production. Critical zone characteristics thus shape biotic function and ecosystem carbon balance. A third example is the effect of riparian zone structure on watershed-scale nitrogen losses. Due to differences in the geomorphology of the riparian zone on volcaniclastic and intrusive bedrock, adjacent watersheds have remarkably different patterns in stream nitrate following hurricanes. Nitrogen losses from these watersheds are driven by interactions between biology and lithology that affect riparian zone function. Finally, in the deep critical zone (5 m) bacterial growth is dominated by autotrophic iron-oxidizing bacteria, with implications for weathering, the development of flow pathways, and solute transport. In this case, biota may be driving the formation of the critical zone through biotic effects on weathering. In each example, our ability to understand the importance of

  3. Assessing Anthropogenic Influence and Edge Effect Influence on Forested Riparian Buffer Spatial Configuration and Structure: An Example Using Lidar Remote Sensing Methods

    NASA Astrophysics Data System (ADS)

    Wasser, L. A.; Chasmer, L. E.

    2012-12-01

    Forested riparian buffers (FRB) perform numerous critical ecosystem services. However, globally, FRB spatial configuration and structure have been modified by anthropogenic development resulting in widespread ecological degradation as seen in the Gulf of Mexico and the Chesapeake Bay. Riparian corridors within developed areas are particularly vulnerable to disturbance given two edges - the naturally occurring stream edge and the matrix edge. Increased edge length predisposes riparian vegetation to "edge effects", characterized by modified physical and environmental conditions at the interface between the forested buffer and the adjacent landuse, or matrix and forest fragment degradation. The magnitude and distance of edge influence may be further influenced by adjacent landuse type and the width of the buffer corridor at any given location. There is a need to quantify riparian buffer spatial configuration and structure over broad geographic extents and within multiple riparian systems in support of ecologically sound management and landuse decisions. This study thus assesses the influence of varying landuse types (agriculture, suburban development and undeveloped) on forested riparian buffer 3-dimensional structure and spatial configuration using high resolution Light Detection and Ranging (LiDAR) data collected within a headwater watershed. Few studies have assessed riparian buffer structure and width contiguously for an entire watershed, an integral component of watershed planning and restoration efforts such as those conducted throughout the Chesapeake Bay. The objectives of the study are to 1) quantify differences in vegetation structure at the stream and matrix influenced riparian buffer edges, compared to the forested interior and 2) assess continuous patterns of changes in vegetation structure throughout the buffer corridor beginning at the matrix edge and ending at the stream within buffers a) of varying width and b) that are adjacent to varying landuse

  4. Environmental tolerance of an invasive riparian tree and its potential for continued spread in the southwestern US

    USGS Publications Warehouse

    Reynolds, L.V.; Cooper, D.J.

    2010-01-01

    Questions: Exotic plant invasion may be aided by facilitation and broad tolerance of environmental conditions, yet these processes are poorly understood in species-rich ecosystems such as riparian zones. In the southwestern United States (US) two plant species have invaded riparian zones: tamarisk (Tamarix ramosissima, T. chinensis, and their hybrids) and Russian olive (Elaeagnus angustifolia). We addressed the following questions: (1) is Russian olive able to tolerate drier and shadier conditions than cottonwood and tamarisk? (2) Can tamarisk and cottonwood facilitate Russian olive invasion? Location: Arid riparian zones, southwestern US. Methods: We analyzed riparian tree seedling requirements in a controlled experiment, performed empirical field studies, and analyzed stable oxygen isotopes to determine the water sources used by Russian olive. Results: Russian olive survival was significantly higher in dense shade and low moisture conditions than tamarisk and cottonwood. Field observations indicated Russian olive established where flooding cannot occur, and under dense canopies of tamarisk, cottonwood, and Russian olive. Tamarisk and native riparian plant species seedlings cannot establish in these dry, shaded habitats. Russian olive can rely on upper soil water until 15 years of age, before utilizing groundwater. Conclusions: We demonstrate that even though there is little evidence of facilitation by cottonwood and tamarisk, Russian olive is able to tolerate dense shade and low moisture conditions better than tamarisk and cottonwood. There is great potential for continued spread of Russian olive throughout the southwestern US because large areas of suitable habitat exist that are not yet inhabited by this species. ?? 2010 International Association for Vegetation Science.

  5. Urbanization and nutrient retention in freshwater riparian wetlands

    USGS Publications Warehouse

    Hogan, D.M.; Walbridge, M.R.

    2007-01-01

    Urbanization can degrade water quality and alter watershed hydrology, with profound effects on the structure and function of both riparian wetlands (RWs) and aquatic ecosystems downstream. We used freshwater RWs in Fairfax County, Virginia, USA, as a model system to examine: (1) the effects of increasing urbanization (indexed by the percentage of impervious surface cover [%ISC] in the surrounding watershed) on nitrogen (N) and phosphorus (P) concentrations in surface soils and plant tissues, soil P saturation, and soil iron (Fe) chemistry; and (2) relationships between RW soil and plant nutrient chemistries vs. the physical and biotic integrity of adjacent streams. Soil total P and NaOH-extractable P (representing P bound to aluminum [Al] and Fe hydrous oxides) varied significantly but nonlinearly with %ISC (r2 = 0.69 and 0.57, respectively); a similar pattern was found for soil P saturation but not for soil total N. Relationships were best described by second-order polynomial equations. Riparian wetlands appear to receive greater P loads in moderately (8.6-13.3% ISC) than in highly (25.1-29.1% ISC) urbanized watersheds. These observations are consistent with alterations in watershed hydrology that occur with increasing urbanization, directing water and nutrient flows away from natural RWs. Significant increases in total and crystalline soil Fe (r 2 = 0.57 and 0.53, respectively) and decreases in relative soil Fe crystallinity with increasing %ISC suggest the mobilization and deposition of terrestrial sediments in RWs, likely due to construction activities in the surrounding watershed. Increases in RW plant tissue nutrient concentrations and %ISC in the surrounding watershed were negatively correlated with standard indices of the physical and biotic integrity of adjacent streams. In combination, these data suggest that nutrient and sediment inputs associated with urbanization and storm-water management are important variables that affect wetland ecosystem services

  6. Urbanization and nutrient retention in freshwater riparian wetlands.

    PubMed

    Hogan, Dianna M; Walbridge, Mark R

    2007-06-01

    Urbanization can degrade water quality and alter watershed hydrology, with profound effects on the structure and function of both riparian wetlands (RWs) and aquatic ecosystems downstream. We used freshwater RWs in Fairfax County, Virginia, USA, as a model system to examine: (1) the effects of increasing urbanization (indexed by the percentage of impervious surface cover [%ISC] in the surrounding watershed) on nitrogen (N) and phosphorus (P) concentrations in surface soils and plant tissues, soil P saturation, and soil iron (Fe) chemistry; and (2) relationships between RW soil and plant nutrient chemistries vs. the physical and biotic integrity of adjacent streams. Soil total P and NaOH-extractable P (representing P bound to aluminum [Al] and Fe hydrous oxides) varied significantly but nonlinearly with % ISC (r2 = 0.69 and 0.57, respectively); a similar pattern was found for soil P saturation but not for soil total N. Relationships were best described by second-order polynomial equations. Riparian wetlands appear to receive greater P loads in moderately (8.6-13.3% ISC) than in highly (25.1-29.1% ISC) urbanized watersheds. These observations are consistent with alterations in watershed hydrology that occur with increasing urbanization, directing water and nutrient flows away from natural RWs. Significant increases in total and crystalline soil Fe (r2 = 0.57 and 0.53, respectively) and decreases in relative soil Fe crystallinity with increasing %ISC suggest the mobilization and deposition of terrestrial sediments in RWs, likely due to construction activities in the surrounding watershed. Increases in RW plant tissue nutrient concentrations and %ISC in the surrounding watershed were negatively correlated with standard indices of the physical and biotic integrity of adjacent streams. In combination, these data suggest that nutrient and sediment inputs associated with urbanization and storm-water management are important variables that affect wetland ecosystem services

  7. Transport through a Heterogeneous Alluvial Aquifer beneath an Agricultural Riparian Buffer

    NASA Astrophysics Data System (ADS)

    Johnson, R.; Mather, A. L.; Smith, E. A.; Green, C. T.

    2012-12-01

    Riparian buffer zones between agricultural fields and streams are intended to attenuate the groundwater transport of non-point-source pollutants. However, if the spatial variability in the alluvial aquifer structure provides pathways for rapid transit across the buffer, the effectiveness for mitigating transport of pollutants to the stream may be limited. The main objective of this work was to examine the effects of alluvial aquifer heterogeneity on groundwater transport beneath an agricultural riparian buffer. This was assessed first by performing a natural-gradient tracer experiment and characterizing the site heterogeneity through hydraulic conductivity profiling. Second, the field hydraulic conductivity data were used with a meandering geostatistical model to represent aquifer heterogeneity and a numerical groundwater model was constructed to simulate the tracer experiment. The tracer experiment showed that a portion of the injected plume (~10% of the total mass) moved at high velocity, while a significant fraction of the mass moved slowly and remained near the injection location. Both the tracer test and the numerical modeling indicate that transport velocities of a meter per day are likely to be present in localized regions throughout the riparian buffer. This highlights the dependence of solute residence time in the riparian zone, and therefore the concentrations arriving in rivers, on the local geological structure.

  8. Riparian Vegetation Influence on Stream Channel Dimensions: Key Driving Mechanisms and Their Timescales

    NASA Astrophysics Data System (ADS)

    McBride, M.; Hession, W.; Rizzo, D. M.; Thompson, D. M.

    2006-05-01

    Combined results from field-based investigations and flume experiments demonstrated key mechanisms driving channel widening following the reforestation of riparian zones in small streams. Riparian reforestation is a common occurrence either due to restoration efforts, intended to improve water quality, temperature regimes, and in-stream physical habitat or due to passive reforestation that is common when agricultural land uses decline. Previous studies have documented the influence of riparian vegetation on channel size, but driving mechanisms and the timescales at which they operate have not been evaluated. Field-based investigations were conducted in the Sleepers River basin in northeastern Vermont to revisit streams that were previously surveyed in the 1960s. We measured channel dimensions, large woody debris (LWD), and steam velocities in reaches with non-forested and forested riparian vegetation, in reaches currently in transition between vegetation types, and reaches with no change in riparian vegetation over the last 40 years. Flume experiments were performed with a 1:5 scale, fixed-bed model of a tributary to Sleepers River. Two types of riparian vegetation scenarios were simulated: 1) forested, with rigid, wooden dowels; and 2) non-forested, with synthetic grass carpeting. Three-dimensional velocities were measured during flume runs to determine turbulent kinetic energy (TKE) during overbank flows. Results showed that stream reaches with recently reforested vegetation have widened since the mid 1960s, but are not as wide as reaches with older riparian forests. LWD was more abundant in reaches with older riparian forests than in reaches with younger forests; however, scour around LWD did not appear to be a significant driving mechanism for channel widening. Velocity and TKE measurements from the prototype stream and the flume model indicate that TKE was significantly elevated in reforested reaches. Given that bed and bank erosion can be amplified in flows

  9. Potential effects of four Flaming Gorge Dam hydropower operational scenarios on riparian vegetation of the Green River, Utah and Colorado

    SciTech Connect

    LaGory, K.E.; Van Lonkhuyzen, R.A.

    1995-06-01

    Four hydropower operational scenarios at Flaming Gorge Dam were evaluated to determine their potential effects on riparian vegetation along the Green River in Utah and Colorado. Data collected in June 1992 indicated that elevation above the river had the largest influence on plant distribution. A lower riparian zone occupied the area between the approximate elevations of 800 and 4,200-cfs flows--the area within the range of hydropower operational releases. The lower zone was dominated by wetland plants such as cattail, common spikerush, coyote willow, juncus, and carex. An upper riparian zone was above the elevation of historical maximum power plant releases from the dam (4,200 cfs), and it generally supported plants adapted to mesic, nonwetland conditions. Common species in the upper zone included box elder, rabbitbrush, grasses, golden aster, and scouring rush. Multispectral aerial videography of the Green River was collected in May and June 1992 to determine the relationship between flow and the areas of water and the riparian zone. From these relationships, it was estimated that the upper zone would decrease in extent by about 5% with year-round high fluctuation, seasonally adjusted high fluctuation, and seasonally adjusted moderate fluctuation, but it would increase by about 8% under seasonally adjusted steady flow. The lower zone would increase by about 13% for both year-round and seasonally adjusted high fluctuation scenarios but would decrease by about 40% and 74% for seasonally adjusted moderate fluctuation and steady flows, respectively. These changes are considered to be relatively minor and would leave pre-dam riparian vegetation unaffected. Occasional high releases above power plant capacity would be needed for long-term maintenance of this relict vegetation.

  10. Assessing water quality at large geographic scales: Relations among land use, water physicochemistry, riparian condition, and fish community structure

    USGS Publications Warehouse

    Meador, M.R.; Goldstein, R.M.

    2003-01-01

    Data collected from 172 sites in 20 major river basins between 1993 and 1995 as part of the US Geological Survey's National Water-Quality Assessment Program were analyzed to assess relations among basinwide land use (agriculture, forest, urban, range), water physicochemistry, riparian condition, and fish community structure. A multimetric approach was used to develop regionally referenced indices of fish community and riparian condition. Across large geographic areas, decreased riparian condition was associated with water-quality constituents indicative of nonpoint source inputs-total nitrogen and suspended sediment and basin-wide urban land use. Decreased fish community condition was associated with increases in total dissolved solids and rangeland use and decreases in riparian condition and agricultural land use. Fish community condition was relatively high even in areas where agricultural land use was relatively high (>50% of the basin). Although agricultural land use can have deleterious effects on fish communities, the results of this study suggest that other factors also may be important, including practices that regulate the delivery of nutrients, suspended sediments, and total dissolved solids into streams. Across large geographic scales, measures of water physicochemistry may be better indicators of fish community condition than basinwide land use. Whereas numerous studies have indicated that riparian restorations are successful in specific cases, this analysis suggests the universal importance of riparian zones to the maintenance and restoration of diverse fish communities in streams.

  11. Statistical evaluation of effects of riparian buffers on nitrate and ground water quality

    USGS Publications Warehouse

    Spruill, T.B.

    2000-01-01

    A study was conducted to statistically evaluate the effectiveness of riparian buffers for decreasing nitrate concentrations in ground water and for affecting other chemical constituents. Values for pH, specific conductance, alkalinity, dissolved organic carbon (DOC), silica, ammonium, phosphorus, iron, and manganese at 28 sites in the Contentnea Creek Basin were significantly higher (p 20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dssolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (20 yr) discharging ground water draining areas with riparian buffers compared with areas without riparian buffers. No differences in chloride, nitrate nitrogen, calcium, sodium, and dissolved oxygen concentrations in old ground water between buffer and nonbuffer areas were detected. Comparison of samples of young (<20 yr) discharging ground water samples from buffer and nonbuffer areas indicated significantly higher specific conductance, calcium, chloride, and nitrate nitrogen in nonbuffer areas. Riparian buffers along streams can affect the composition of the hyporheic zone by providing a source of organic carbon to the streambed, which creates reducing geochemical conditions that consequently can affect the chemical quality of old ground water discharging through it. Buffer zones between agricultural fields and streams facilitate dilution of conservative chemical constituents in young ground water that originate from fertilizer applications and also allow denitrification in ground water by providing an adequate source of organic carbon generated by vegetation in the buffer zone. Based on the median chloride and nitrate values for young ground water in the Contentnea Creek Basin, nitrate was 95% lower in buffer areas compared with nonbuffer areas, with a 30 to 35% reduction

  12. Riparian Vegetation Status and Rates of Water Use from Satellite Data

    NASA Astrophysics Data System (ADS)

    Sheffield, K.; Abuzar, M.; Whitfield, D.; McAllister, A.; O'Connell, M.

    2012-07-01

    Hydrology and water availability are key determinants of the health of riparian vegetation systems, and an understanding of the interactions between vegetation and hydrology is a prerequisite for the maintenance and improvement of these systems under managed water regimes. Changes to natural flooding cycles, caused by the regulation of river flows and irrigation activities, have changed the composition and amount of vegetation, and the distribution of species within riparian areas (Chong and Ladson, 2003; Lawrence and Colloff, 2008). The extent and frequency of flooding cycles are key issues for the health of riparian ecosystems under controlled water management regimes. This paper demonstrates the potential contribution of satellite-based measurements to an improved understanding of the changes in vegetation status of riparian systems, and, also, of their water requirement. Evapotranspiration (ET) and Normalised Difference Vegetation Index (NDVI) of the Barmah Forest were derived from satellite imagery over a number of years. NDVI provided a general measure of vegetation status and cover. ET measures provided an indication of the availability of water to the existing vegetation, and an assessment of areas under water-stress (Anderson et al., 2012). Previous work has demonstrated that these indicators provide a comprehensive measure of riparian vegetation status (Sheffield et al., 2011), and estimates of vegetation water requirement (Whitfield et al., 2010a; Sheffield et al., 2011). This paper addresses changes in NDVI and ET rate of major vegetation classes in the Barmah Forest over the period, 1993 - 2008. Measures of ET and NDVI, analysed in conjunction with rainfall and river flow data, provided insights into the response of vegetation to changes in water availability, which may be used to evaluate impacts of management practices and water regime within riparian zones.

  13. Estimating riparian and agricultural evapotranspiration by reference crop evapotranspiration and MODIS Enhanced Vegetation Index

    USGS Publications Warehouse

    Nagler, Pamela L.; Glenn, Edward P.; Nguyen, Uyen; Scott, Russell; Doody, Tania

    2013-01-01

    Dryland river basins frequently support both irrigated agriculture and riparian vegetation and remote sensing methods are needed to monitor water use by both crops and natural vegetation in irrigation districts. We developed an algorithm for estimating actual evapotranspiration (ETa) based on the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imaging Spectrometer (MODIS) sensor on the EOS-1 Terra satellite and locally-derived measurements of reference crop ET (ETo). The algorithm was calibrated with five years of ETa data from three eddy covariance flux towers set in riparian plant associations on the upper San Pedro River, Arizona, supplemented with ETa data for alfalfa and cotton from the literature. The algorithm was based on an equation of the form ETa = ETo [a(1 − e−bEVI) − c], where the term (1 − e−bEVI) is derived from the Beer-Lambert Law to express light absorption by a canopy, with EVI replacing leaf area index as an estimate of the density of light-absorbing units. The resulting algorithm capably predicted ETa across riparian plants and crops (r2 = 0.73). It was then tested against water balance data for five irrigation districts and flux tower data for two riparian zones for which season-long or multi-year ETa data were available. Predictions were within 10% of measured results in each case, with a non-significant (P = 0.89) difference between mean measured and modeled ETa of 5.4% over all validation sites. Validation and calibration data sets were combined to present a final predictive equation for application across crops and riparian plant associations for monitoring individual irrigation districts or for conducting global water use assessments of mixed agricultural and riparian biomes.

  14. Geography of spring landbird migration through riparian habitats in southwestern North America

    USGS Publications Warehouse

    Skagen, S.K.; Kelly, J.F.; van Riper, Charles; Hutto, R.L.; Finch, D.M.; Krueper, D.J.; Melcher, C.P.

    2005-01-01

    Migration stopover resources, particularly riparian habitats, are critically important to landbirds migrating across the arid southwestern region of North America. To explore the effects of species biogeography and habitat affinity on spring migration patterns, we synthesized existing bird abundance and capture data collected in riparian habitats of the borderlands region of the U.S. and Mexico. We determined the importance of geographic factors (longitude and latitude) in explaining variation in abundances and capture rates of 32 long-distance and three short-distance migrant species. Abundances and capture rates of 12 and 11 species, respectively, increased with increasing longitude, and four speciesa?? abundance and capture rates decreased with increasing longitude. Riparian associates, but not nonriparian species, were more abundant in western sites. Their abundance patterns were only weakly influenced by species biogeography in contrast, biogeography did influence abundance patterns of nonriparian birds, suggesting that they choose the shortest, most direct route between wintering and breeding areas. We hypothesize that riparian obligate birds may, to some degree, adjust their migration routes to maximize time spent in high-quality riparian zones, but they are able to find suitable habitat opportunistically when crossing more hostile landscapes. In contrast, nonriparian birds adhere more closely to a hierarchical model in which the migratory route is determined by biogeographic constraints. Conservation of riparian habitats is necessary to meet future habitat stopover requirements of many western Neotropical migrant birds. We advocate a coordinated research effort to further elucidate patterns of distribution and habitat use so that conservation activities can be focused effectively.

  15. Hydrological connectivity inferred from diatom transport through the riparian-stream system

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, N.; Wetzel, C. E.; Frentress, J.; Ector, L.; McDonnell, J. J.; Hoffmann, L.; Pfister, L.

    2015-07-01

    Diatoms (Bacillariophyta) are one of the most common and diverse algal groups (ca. 200 000 species, ≈ 10-200 μm, unicellular, eukaryotic). Here we investigate the potential of aerial diatoms (i.e. diatoms nearly exclusively occurring outside water bodies, in wet, moist or temporarily dry places) to infer surface hydrological connectivity between hillslope-riparian-stream (HRS) landscape units during storm runoff events. We present data from the Weierbach catchment (0.45 km2, northwestern Luxembourg) that quantify the relative abundance of aerial diatom species on hillslopes and in riparian zones (i.e. surface soils, litter, bryophytes and vegetation) and within streams (i.e. stream water, epilithon and epipelon). We tested the hypothesis that different diatom species assemblages inhabit specific moisture domains of the catchment (i.e. HRS units) and, consequently, the presence of certain species assemblages in the stream during runoff events offers the potential for recording whether there was hydrological connectivity between these domains or not. We found that a higher percentage of aerial diatom species was present in samples collected from the riparian and hillslope zones than inside the stream. However, diatoms were absent on hillslopes covered by dry litter and the quantities of diatoms (in absolute numbers) were small in the rest of hillslope samples. This limits their use for inferring hillslope-riparian zone connectivity. Our results also showed that aerial diatom abundance in the stream increased systematically during all sampled events (n = 11, 2011-2012) in response to incident precipitation and increasing discharge. This transport of aerial diatoms during events suggested a rapid connectivity between the soil surface and the stream. Diatom transport data were compared to two-component hydrograph separation, and end-member mixing analysis (EMMA) using stream water chemistry and stable isotope data. Hillslope overland flow was insignificant during

  16. Hydrological connectivity as indicated by transport of diatoms through the riparian-stream system

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, N.; Wetzel, C. E.; Frentress, J.; Ector, L.; McDonnell, J. J.; Hoffmann, L.; Pfister, L.

    2015-02-01

    Diatoms (Bacillariophyta) are one of the most common and diverse algal groups (ca. 200 000 species, ≈10-200 μm, unicellular, eukaryotic). Here we investigate the potential of terrestrial and aerophytic diatoms (i.e. diatoms nearly exclusively occurring outside water bodies, on wet, moist or temporarily dry places) to infer surface hydrological connectivity between hillslope-riparian-stream (HRS) landscape units during storm runoff events. We present data from the Weierbach catchment (0.45 km2, NW Luxembourg) that quantifies the relative abundance of terrestrial and aerophytic diatom species on hillslopes and in riparian zones (i.e. surface soils, litter, bryophytes and vegetation) and within streams (i.e. stream water, epilithon and epipelon). We tested the hypothesis that different diatom species assemblages inhabit specific moisture domains of the catchment (i.e. HRS units) and, consequently, the presence of certain species assemblages in the stream during runoff events offers the potential for recording if there was or not hydrological connectivity between these domains. We found that a higher percentage of terrestrial and aerophytic diatom species was present in samples collected from the riparian and hillslope zones than inside the stream. However, diatoms were absent on hillslopes covered by dry litter, limiting their use to infer hillslope-riparian zone connectivity in some parts of the catchment. Our results also showed that terrestrial and aerophytic diatom abundance in the stream increased systematically during all sampled events (n = 11, 2010-2011) in response to incident precipitation and increasing discharge. This transport of terrestrial and aerophytic diatoms during events suggested a rapid connectivity between the soil surface and the stream. Diatom transport data was compared to two-component hydrograph separation, and end-member mixing analysis (EMMA) using stream water chemistry and stable isotope data. This research suggests that diatoms were

  17. Hiawatha National Forest Riparian Inventory: A Case Study

    NASA Astrophysics Data System (ADS)

    Abood, S. A.

    2014-12-01

    Riparian areas are dynamic, transitional ecotones between aquatic and terrestrial ecosystems with well-defined vegetation and soil characteristics. Riparian areas offers wildlife habitat and stream water quality, offers bank stability and protects against erosions, provides aesthetics and recreational value, and other numerous valuable ecosystem functions. Quantifying and delineating riparian areas is an essential step in riparian monitoring, riparian management/planning and policy decisions, and in preserving its valuable ecological functions. Previous approaches to riparian areas mapping have primarily utilized fixed width buffers. However, these methodologies only take the watercourse into consideration and ignore critical geomorphology, associated vegetation and soil characteristics. Other approaches utilize remote sensing technologies such as aerial photos interpretation or satellite imagery riparian vegetation classification. Such techniques requires expert knowledge, high spatial resolution data, and expensive when mapping riparian areas on a landscape scale. The goal of this study is to develop a cost effective robust workflow to consistently map the geographic extent and composition of riparian areas within the Hiawatha National Forest boundary utilizing the Riparian Buffer Delineation Model (RBDM) v3.0 and open source geospatial data. This approach recognizes the dynamic and transitional natures of riparian areas by accounting for hydrologic, geomorphic and vegetation data as inputs into the delineation process and the results would suggests incorporating functional variable width riparian mapping within watershed management planning to improve protection and restoration of valuable riparian functionality and biodiversity.

  18. Stream hydrology limits recovery of riparian ecosystems after wolf reintroduction.

    PubMed

    Marshall, Kristin N; Hobbs, N Thompson; Cooper, David J

    2013-04-01

    Efforts to restore ecosystems often focus on reintroducing apex predators to re-establish coevolved relationships among predators, herbivores and plants. The preponderance of evidence for indirect effects of predators on terrestrial plant communities comes from ecosystems where predators have been removed. Far less is known about the consequences of their restoration. The effects of removal and restoration are unlikely to be symmetrical because removing predators can create feedbacks that reinforce the effects of predator loss. Observational studies have suggested that the reintroduction of wolves to Yellowstone National Park initiated dramatic restoration of riparian ecosystems by releasing willows from excessive browsing by elk. Here, we present results from a decade-long experiment in Yellowstone showing that moderating browsing alone was not sufficient to restore riparian zones along small streams. Instead, restoration of willow communities depended on removing browsing and restoring hydrological conditions that prevailed before the removal of wolves. The 70-year absence of predators from the ecosystem changed the disturbance regime in a way that was not reversed by predator reintroduction. We conclude that predator restoration may not quickly repair effects of predator removal in ecosystems.

  19. Stream hydrology limits recovery of riparian ecosystems after wolf reintroduction

    PubMed Central

    Marshall, Kristin N.; Hobbs, N. Thompson; Cooper, David J.

    2013-01-01

    Efforts to restore ecosystems often focus on reintroducing apex predators to re-establish coevolved relationships among predators, herbivores and plants. The preponderance of evidence for indirect effects of predators on terrestrial plant communities comes from ecosystems where predators have been removed. Far less is known about the consequences of their restoration. The effects of removal and restoration are unlikely to be symmetrical because removing predators can create feedbacks that reinforce the effects of predator loss. Observational studies have suggested that the reintroduction of wolves to Yellowstone National Park initiated dramatic restoration of riparian ecosystems by releasing willows from excessive browsing by elk. Here, we present results from a decade-long experiment in Yellowstone showing that moderating browsing alone was not sufficient to restore riparian zones along small streams. Instead, restoration of willow communities depended on removing browsing and restoring hydrological conditions that prevailed before the removal of wolves. The 70-year absence of predators from the ecosystem changed the disturbance regime in a way that was not reversed by predator reintroduction. We conclude that predator restoration may not quickly repair effects of predator removal in ecosystems. PMID:23390108

  20. Woody riparian vegetation of Great Basin National Park. Interim report

    SciTech Connect

    Douglas, C.L.; Smith, S.D.; Murray, K.J.; Landau, F.H.; Sala, A.

    1994-07-01

    The community composition and population structure of the woody riparian vegetation in Great Basin National Park are described. Community analyses were accomplished by sampling 229 plots placed in a systematic random fashion along elevational gradients of 8 major stream systems (Baker, Big Wash, Lehman, Pine, Pole, Shingle, Snake, and Strawberry Creeks) in the Park using the releve method. Stand demographics were determined for the four dominant tree species in the Park, based on absolute stem counts at 15 sites along 6 major watersheds. Elevational ranges of the dominant tree and shrub species along 8 major streams were determined via transect analysis and systematic reconnaissance efforts. TWINSPAN (two-way indicator analysis) indentified 4 primary species groups and 8 stand groups in the Park. Because of the homogeneity of riparian zones, both presence and abundance of species were important parameters in determining species groups. Although species such as Populus tremuloides (aspen), Abies concolor (white fir) and Rosa woodsii (Woods rose) are very common throughout the Park, they are particularly abundant at higher, upper intermediate, and lower intermediate elevations.

  1. Stream hydrology limits recovery of riparian ecosystems after wolf reintroduction.

    PubMed

    Marshall, Kristin N; Hobbs, N Thompson; Cooper, David J

    2013-04-01

    Efforts to restore ecosystems often focus on reintroducing apex predators to re-establish coevolved relationships among predators, herbivores and plants. The preponderance of evidence for indirect effects of predators on terrestrial plant communities comes from ecosystems where predators have been removed. Far less is known about the consequences of their restoration. The effects of removal and restoration are unlikely to be symmetrical because removing predators can create feedbacks that reinforce the effects of predator loss. Observational studies have suggested that the reintroduction of wolves to Yellowstone National Park initiated dramatic restoration of riparian ecosystems by releasing willows from excessive browsing by elk. Here, we present results from a decade-long experiment in Yellowstone showing that moderating browsing alone was not sufficient to restore riparian zones along small streams. Instead, restoration of willow communities depended on removing browsing and restoring hydrological conditions that prevailed before the removal of wolves. The 70-year absence of predators from the ecosystem changed the disturbance regime in a way that was not reversed by predator reintroduction. We conclude that predator restoration may not quickly repair effects of predator removal in ecosystems. PMID:23390108

  2. The impact of flood variables on riparian vegetation

    NASA Astrophysics Data System (ADS)

    Dzubakova, Katarina; Molnar, Peter

    2016-04-01

    The riparian vegetation of Alpine rivers often grows in temporally dynamic riverine environments which are characterized by pronounced meteorological and hydrological fluctuations and high resource competition. Within these relatively rough conditions, riparian vegetation fulfils essential ecosystem functions such as water retention, biomass production and habitat to endangered species. The identification of relevant flood attributes impacting riparian vegetation is crucial for a better understanding of the vegetation dynamics in the riverine ecosystem. Hence, in this contribution we aim to quantify the ecological effects of flood attributes on riparian vegetation and to analyze the spatial coherence of flood-vegetation interaction patterns. We analyzed a 500 m long and 300-400 m wide study reach located on the Maggia River in southern Switzerland. Altogether five floods between 2008 and 2011 with return periods ranging from 1.4 to 20.1 years were studied. To assess the significance of the flood attributes, we compared post-flood to pre-flood vegetation vigour to flood intensity. Pre- and post-flood vegetation vigour was represented by the Normalized Difference Vegetation Index (NDVI) which was computed from images recorded by high resolution ground-based cameras. Flood intensity was expressed in space in the study reach by six flood attributes (inundation duration, maximum depth, maximum and total velocity, maximum and total shear stress) which were simulated by the 2D hydrodynamic model BASEMENT (VAW, ETH Zurich). We considered three floodplain units separately (main bar, secondary bar, transitional zone). Based on our results, pre-flood vegetation vigour largely determined vegetation reaction to the less intense floods (R = 0.59-0.96). However for larger floods with a strong erosive effect, its contribution was significantly lower (R = 0.59-0.68). Using multivariate regression analysis we show that pre-flood vegetation vigour and maximum velocity proved to be

  3. Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

    USGS Publications Warehouse

    Komor, S.C.; Magner, J.A.

    1996-01-01

    This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of ??D values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate- poor, deep groundwater. Upwelling deep groundwater contained ammonium with a ??15N of 5??? that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate ??15N values in shallow groundwater to decrease by as much as 19.5???. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass- shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these

  4. Nitrate in ground water and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

    USGS Publications Warehouse

    Komor, Stephen C.; Magner, J.

    1996-01-01

    This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of δD values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate-poor, deep groundwater. Upwelling deep groundwater contained ammonium with a δ15N of 5‰ that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate δ15N values in shallow groundwater to decrease by as much as 19.5‰. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass-shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these

  5. Riparian vegetation, Colorado River, and climate: Five decades of spatiotemporal dynamics in the Grand Canyon with river regulation

    NASA Astrophysics Data System (ADS)

    Sankey, Joel B.; Ralston, Barbara E.; Grams, Paul E.; Schmidt, John C.; Cagney, Laura E.

    2015-08-01

    Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, coupled with the instantaneous hydrograph for the entire period. Analysis confirms a net increase in vegetated area since completion of the dam. Magnitude and timing of such vegetation changes are river stage-dependent. Vegetation expansion is coincident with inundation frequency changes and is unlikely to occur for time periods when inundation frequency exceeds approximately 5%. Vegetation expansion at lower zones of the riparian area is greater during the periods with lower peak and higher base flows, while vegetation at higher zones couples with precipitation patterns and decreases during drought. Short pulses of high flow, such as the controlled floods of the Colorado River in 1996, 2004, and 2008, do not keep vegetation from expanding onto bare sand habitat. Management intended to promote resilience of riparian vegetation must contend with communities that are sensitive to the interacting effects of altered flood regimes and water availability from river and precipitation.

  6. Riparian vegetation, Colorado River, and climate: five decades of spatiotemporal dynamics in the Grand Canyon with river regulation

    USGS Publications Warehouse

    Sankey, Joel B.; Ralston, Barbara; Grams, Paul E.; Schmidt, John C.; Cagney, Laura E.

    2015-01-01

    Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, coupled with the instantaneous hydrograph for the entire period. Analysis confirms a net increase in vegetated area since completion of the dam. Magnitude and timing of such vegetation changes are river stage-dependent. Vegetation expansion is coincident with inundation frequency changes and is unlikely to occur for time periods when inundation frequency exceeds approximately 5%. Vegetation expansion at lower zones of the riparian area is greater during the periods with lower peak and higher base flows, while vegetation at higher zones couples with precipitation patterns and decreases during drought. Short pulses of high flow, such as the controlled floods of the Colorado River in 1996, 2004, and 2008, do not keep vegetation from expanding onto bare sand habitat. Management intended to promote resilience of riparian vegetation must contend with communities that are sensitive to the interacting effects of altered flood regimes and water availability from river and precipitation.

  7. RIPARIAN RESTORATION: CURRENT STATUS AND THE REACH TO THE FUTURE

    EPA Science Inventory

    Nine articles in the special issure of Restoration Ecology addressing the subject of site selection for riparian restoration activities were critically examined for this review. The approaches described make significant and original contributions to the field of riparian restorat...

  8. ASSESSING ARID RIPARIAN LANDSCAPES USING REMOTE SENSING: THE FIRST STEP

    EPA Science Inventory

    Riparian ecosystems are of great value in the Southwest yet they are also extremely fragile and susceptible to natural and anthropogenic disturbances. Riparian ecosystems establish in patterns per the hydrologic and geomorphologic processes that dictate terrestrial plant success...

  9. VEGETATION CHARACTERIZATION OF THREE CONTRASTING RIPARIAN SITES, WILLAMETTE VALLEY, OR

    EPA Science Inventory

    Much of the native riparian vegetation of the Willamette Valley, Oregon, has been replaced with agricultural crops or invasive non-native plant species. Detailed information about current Willamette Valley riparian vegetation is generally lacking. Plant species composition data...

  10. Mapping of riparian invasive species with supervised classification of Unmanned Aerial System (UAS) imagery

    NASA Astrophysics Data System (ADS)

    Michez, Adrien; Piégay, Hervé; Jonathan, Lisein; Claessens, Hugues; Lejeune, Philippe

    2016-02-01

    Riparian zones are key landscape features, representing the interface between terrestrial and aquatic ecosystems. Although they have been influenced by human activities for centuries, their degradation has increased during the 20th century. Concomitant with (or as consequences of) these disturbances, the invasion of exotic species has increased throughout the world's riparian zones. In our study, we propose a easily reproducible methodological framework to map three riparian invasive taxa using Unmanned Aerial Systems (UAS) imagery: Impatiens glandulifera Royle, Heracleum mantegazzianum Sommier and Levier, and Japanese knotweed (Fallopia sachalinensis (F. Schmidt Petrop.), Fallopia japonica (Houtt.) and hybrids). Based on visible and near-infrared UAS orthophoto, we derived simple spectral and texture image metrics computed at various scales of image segmentation (10, 30, 45, 60 using eCognition software). Supervised classification based on the random forests algorithm was used to identify the most relevant variable (or combination of variables) derived from UAS imagery for mapping riparian invasive plant species. The models were built using 20% of the dataset, the rest of the dataset being used as a test set (80%). Except for H. mantegazzianum, the best results in terms of global accuracy were achieved with the finest scale of analysis (segmentation scale parameter = 10). The best values of overall accuracies reached 72%, 68%, and 97% for I. glandulifera, Japanese knotweed, and H. mantegazzianum respectively. In terms of selected metrics, simple spectral metrics (layer mean/camera brightness) were the most used. Our results also confirm the added value of texture metrics (GLCM derivatives) for mapping riparian invasive species. The results obtained for I. glandulifera and Japanese knotweed do not reach sufficient accuracies for operational applications. However, the results achieved for H. mantegazzianum are encouraging. The high accuracies values combined to

  11. Using monitoring, LiDAR and MODFLOW to Estimate Hyporheic Fluxes for a Dynamic Large River Riparian Area

    EPA Science Inventory

    In unrevetted reaches, the Willamette River in northwest Oregon is a dynamic anastomosing system. Riparian zones are frequently divided into multiple islands during most of the wet winter season. The dividing stream channels are mostly absent during the dry summer season. This po...

  12. Riparian Areas of the Southwest: Learning from Repeat Photographs

    ERIC Educational Resources Information Center

    Zaimes, George N.; Crimmins, Michael A.

    2010-01-01

    Spatial and temporal variability of riparian areas, as well as potential impacts from climate change, are concepts that land and water managers and stakeholders need to understand to effectively manage and protect riparian areas. Rapid population growth in the southwestern United States, and multiple-use designation of most riparian areas, makes…

  13. A Review of Effectiveness of Riparian Buffers in Agricultural Areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been growing recognition of the importance of riparian buffers between agricultural fields and waterbodies in recent years. Riparian buffers play an important role in mitigating the impacts of land use activities on water quality and aquatic ecosystems. Riparian buffer systems have been st...

  14. Riparian forests buffer panel final report

    SciTech Connect

    1996-10-01

    The Chesapeake Executive Council adopted Directive 94-1 which called upon the Chesapeake Bay Program to develop a set of goals and actions to increase the focus on riparian stewardship and enhance efforts to conserve and restore riparian forest buffers. The Council appointed a panel to recommend a set of policies, recommend an accepted definition of forest buffers, and suggest quantifiable goals. The Panel was a diverse group of thirty-one members, comprised of federal, state, and local government representatives, scientists, land managers, citizens, and farming, development, forest industry, and environmental interests. This report contains our principal findings and recommendations.

  15. Environmental services provided from riparian forests in the Nordic countries.

    PubMed

    Gundersen, Per; Laurén, Ari; Finér, Leena; Ring, Eva; Koivusalo, Harri; Saetersdal, Magne; Weslien, Jan-Olov; Sigurdsson, Bjarni D; Högbom, Lars; Laine, Jukka; Hansen, Karin

    2010-12-01

    Riparian forests (RF) growing along streams, rivers and lakes comprise more than 2% of the forest area in the Nordic countries (considering a 10 m wide zone from the water body). They have special ecological functions in the landscape. They receive water and nutrients from the upslope areas, are important habitats for biodiversity, have large soil carbon stores, but may emit more greenhouse gases (GHG) than the uplands. In this article, we present a review of the environmental services related to water protection, terrestrial biodiversity, carbon storage and greenhouse gas dynamics provided by RF in the Nordic countries. We discuss the benefits and trade-offs when leaving the RF as a buffer against the impacts from upland forest management, in particular the impacts of clear cutting. Forest buffers are effective in protecting water quality and aquatic life, and have positive effects on terrestrial biodiversity, particularly when broader than 40 m, whereas the effect on the greenhouse gas exchange is unclear. PMID:21141775

  16. Cooling Along Hyporheic Pathlines in a Large River Riparian Zone

    EPA Science Inventory

    Floodplains can contribute to hyporheic cooling and moderation of temperature for rivers, but extent and magnitude are dependent on ground water hydrology. Here we illustrate the controls and dynamics of hyporheic cooling in the ground water of a large river floodplain with field...

  17. COLLABORATIVE RESEARCH: STREAMFLOW, URBAN RIPARIAN ZONES, BMPS, AND IMPERVIOUS SURFACES

    EPA Science Inventory

    The U.S. EPA Landscape Ecology Branch (LEB) in Research Triangle Park, North Carolina is currently conducting collaborative landscape/stream ecology research in the Clarksburg Special Protection Area (CSPA) in Montgomery County, Maryland. The CSPA subwatersheds are on the outer e...

  18. Stream Community Structure: An Analysis of Riparian Forest Buffer Restoration in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Orzetti, L. L.; Jones, R. C.

    2005-05-01

    Forested riparian buffer zones have been proposed as an important aid in curtailing upland sources of pollution before they reach stream surface waters, and enhancing habitat for stream organisms. Our objective was to test the efficacy of restored forest riparian buffers along streams in the Chesapeake Bay watershed by examining the stream macrobenthic community structure. To test our hypothesis, we collected riffle benthic and water samples, and performed habitat evaluations at 30 stream sites in the mid-Atlantic Piedmont, ranging in buffer age from 0 to greater than 50 years of age. Results showed that habitat, water quality, and benthic macroinvertebrate metrics improved with age of restored buffer. Habitat scores were driven mostly by instream substrate availability and width and age of riparian buffer zones. Water quality parameters varied within buffer age groups depending age of surrounding forest vegetation. Benthic invertebrate taxa richness, % EPT, % Plecoptera, % Ephemeroptera, and the FBI all improved with age of buffer zone. Instream habitat quality was the greatest driver of benthic macroinvertebrate community diversity and health, and appeared to plateau within 10-15 years of restoration with noticeable improvements occurring within 5-10 years post restoration.

  19. Getting Terrestrial Carbon into the Aquatic Conduit: Riparian peat controls from daily to centennial time-scales

    NASA Astrophysics Data System (ADS)

    Bishop, Kevin; Ledesma, Jose; Grabs, Thomas; Wallin, Marcus; Schiff, Sherry; Campeau, Audrey; Köhler, Stephan; Leith, Fraser

    2015-04-01

    Riparian zones (RZ) are important sources of biogenic carbon (both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC)) reaching surface waters. This is the so-called "aquatic conduit" that returns large quantities of terrestrial carbon to the atmosphere. But it is often just a narrow 'dominant source layer' (DSL) within the riparian profile that is responsible of most of the carbon production and water to surface waters. But how long can this fraction of the RZ sustain lateral DOC/DIC fluxes as the sole source of exported carbon? This study estimates this theoretical turnover time of carbon and water in the DSL by comparing carbon/water pools and lateral fluxes in the DSL of 13 riparian profiles in northern Sweden. The thickness of the DSL was 36 ± 18 (±SD) cm, i.e. only about one third of the 1 metre deep riparian profile. The 13 RZ exported 8.7 ± 6.5 g C m-2 year-1. The estimated C turnover times were of the order of hundreds to thousands of years, while water residence time varied from hours to weeks. Net ecosystem production in the RZ can maintain the C export, including inorganic C, without drawing down the riparian pools. This was supported by measurements of stream DO14C that indicate modern carbon as the predominant fraction exported. Upscaling these results using representative data sets of stream DOC and CO2 concentrations, an empirically derived gas transfer model and the characteristics of a virtual stream network of Sweden enables us to present national CO2 emission and DOC export estimates for all Swedish headwater streams. These results further underline the importance of the riparian zone for terrestrial carbon export in the boreal/hemiboreal zone.

  20. Mature and old-growth riparian forests: structure, dynamics, and effects on Adirondack stream habitats.

    PubMed

    Keeton, William S; Kraft, Clifford E; Warren, Dana R

    2007-04-01

    Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in

  1. Conservation of soil, water and nutrients in surface runoff using riparian plant species.

    PubMed

    Srivastava, Prabodh; Singh, Shipra

    2012-01-01

    Three riparian plant species viz. Cynodon dactylon (L.) Pers., Saccharum bengalensis Retz. and Parthenium hysterophorus L. were selected from the riparian zone of Kali river at Aligarh to conduct the surface runoff experiment to compare their conservation efficiencies for soil, water and nutrients (phosphorus and nitrogen). Experimental plots were prepared on artificial slopes in botanical garden and on natural slopes on study site. Selected riparian plant species showed the range of conservation values for soil and water from 47.11 to 95.22% and 44.06 to 72.50%, respectively on artificial slope and from 44.53 to 95.33% and 48.36 to 73.15%, respectively on natural slope. Conservation values for phosphorus and nitrogen ranged from 40.83 to 88.89% and 59.78 to 82.22%, respectively on artificial slope and from 50.01 to 90.16% and 68.07 to 85.62%, respectively on natural slope. It was observed that Cynodon dactylon was the most efficient riparian species in conservation of soil, water and nutrients in surface runoff. PMID:23033642

  2. Evapotranspiration Rates of Riparian Forests, Platte River, Nebraska, 2002-06

    USGS Publications Warehouse

    Landon, Matthew K.; Rus, David L.; Dietsch, Benjamin J.; Johnson, Michaela R.; Eggemeyer, Kathleen D.

    2009-01-01

    Evapotranspiration (ET) in riparian areas is a poorly understood component of the regional water balance in the Platte River Basin, where competing demands have resulted in water shortages in the ground-water/surface-water system. From April 2002 through March 2006, the U.S. Geological Survey, Nebraska Platte River Cooperative Hydrology Study Group, and Central Platte Natural Resources District conducted a micrometeorological study of water and energy balances at two sites in central Nebraska near Odessa and Gothenburg to improve understanding of ET rates and factors affecting them in Platte River riparian forests. A secondary objective of the study was to constrain estimates of ground-water use by riparian vegetation to satisfy ET consumptive demands, a useful input to regional ground-water flow models. Both study sites are located on large islands within the Platte River characterized by a cottonwood-dominated forest canopy on primarily sandy alluvium. Although both sites are typical of riparian forests along the Platte River in Nebraska, the Odessa understory is dominated by deciduous shrubs, whereas the Gothenburg understory is dominated by eastern redcedars. Additionally, seasonal ground-water levels fluctuated more at Odessa than at Gothenburg. The study period of April 2002 through March 2006 encompassed precipitation conditions ranging from dry to wet. This study characterized the components of the water balance in the riparian zone of each site. ET was evaluated from eddy-covariance sensors installed on towers above the forest canopy at a height of 26.1 meters. Precipitation was measured both above and below the forest canopy. A series of sensors measured soil-moisture availability within the unsaturated zone in two different vertical profiles at each site. Changes in ground-water altitude were evaluated from piezometers. The areal footprint represented in the water balance extended up to 800 meters from each tower. During the study, ET was less variable

  3. Effect of riparian vegetation on diatom assemblages in headwater streams under different land uses.

    PubMed

    Hlúbiková, Daša; Novais, Maria Helena; Dohet, Alain; Hoffmann, Lucien; Ector, Luc

    2014-03-15

    Differences in the structure of diatom assemblages in headwaters with contrasting shading conditions and different land use in the buffer zone and upper catchment were studied in order to evaluate the influence of the lack of riparian vegetation on the biofilm. The objective was to ascertain whether a riparian buffer can mitigate the negative influence of human induced disturbance and pollution on diatom assemblages in headwaters. Four streams were selected in order to maximize the differences in the land cover and minimize other environmental gradients. Multivariate statistics, different comparative and permutation tests and correlations were applied to compare the diatom assemblages, the Specific Polluosensitivity Index (IPS) and the diatom ecological guilds (low profile, high profile and motile) among the sites studied and to evaluate their responses to disturbances. The analysis showed that low profile diatoms typically dominated in forested headwaters with limited resources, whilst assemblages at impacted sites showed a wider range of growth forms. In unimpacted streams, the diatom assemblages were influenced by temperature, pH, conductivity and calcium, as usually reported for oligotrophic streams with high natural disturbance due to fast current and shading. In both shaded and unshaded impacted streams, the importance of nutrients and land use disturbance, especially urbanization, prevailed. This trend was also reflected by the IPS index that showed consistently lower values at impacted sites, correlating most significantly with nutrients. The diatom species composition as well as diatom guilds at impacted sites were similar, regardless of the presence or absence of riparian vegetation, and were significantly influenced by seasonal changes. Our results indicate that diatoms react sensitively to alterations of the water environment in headwaters, induced by anthropogenic activities, and these impacts are not buffered by an intact riparian zone. Diatoms

  4. Value of Riparian Vegetation Remnants for Leaf-Litter Ants (Hymenoptera: Formicidae) in a Human-Dominated Landscape in Central Veracruz, Mexico.

    PubMed

    García-Martínez, Miguel Á; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela; Valenzuela-González, Jorge E

    2015-12-01

    Riparian remnants are linear strips of vegetation immediately adjacent to rivers that may act as refuges for biodiversity, depending on their habitat quality. In this study, we evaluated the role of riparian remnants in contributing to the diversity of leaf-litter ants by determining the relationship between ant diversity and several riparian habitat characteristics within a human-dominated landscape in Veracruz, Mexico. Sampling was carried out in 2012 during both dry and rainy seasons at 12 transects 100 m in length, where 10 leaf-litter samples were collected along each transect and processed with Berlese-Tullgren funnels and Winkler sacks. A total of 8,684 individuals belonging to 53 species, 22 genera, and seven subfamilies were collected. The observed mean alpha diversity accounted for 34.4% of the total species recorded and beta diversity for 65.6%. Species richness and composition were significantly related to litter-layer depth and soil compaction, which could limit the distribution of ant species depending on their nesting, feeding, and foraging habits. Riparian remnants can contribute toward the conservation of ant assemblages and likely other invertebrate communities that are threatened by anthropogenic pressures. In human-dominated landscapes where remnants of riparian vegetation give refuge to a diverse array of myrmecofauna, the protection of the few remaining and well-preserved riparian sites is essential for the long-term maintenance of biodiversity.

  5. Value of Riparian Vegetation Remnants for Leaf-Litter Ants (Hymenoptera: Formicidae) in a Human-Dominated Landscape in Central Veracruz, Mexico.

    PubMed

    García-Martínez, Miguel Á; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela; Valenzuela-González, Jorge E

    2015-12-01

    Riparian remnants are linear strips of vegetation immediately adjacent to rivers that may act as refuges for biodiversity, depending on their habitat quality. In this study, we evaluated the role of riparian remnants in contributing to the diversity of leaf-litter ants by determining the relationship between ant diversity and several riparian habitat characteristics within a human-dominated landscape in Veracruz, Mexico. Sampling was carried out in 2012 during both dry and rainy seasons at 12 transects 100 m in length, where 10 leaf-litter samples were collected along each transect and processed with Berlese-Tullgren funnels and Winkler sacks. A total of 8,684 individuals belonging to 53 species, 22 genera, and seven subfamilies were collected. The observed mean alpha diversity accounted for 34.4% of the total species recorded and beta diversity for 65.6%. Species richness and composition were significantly related to litter-layer depth and soil compaction, which could limit the distribution of ant species depending on their nesting, feeding, and foraging habits. Riparian remnants can contribute toward the conservation of ant assemblages and likely other invertebrate communities that are threatened by anthropogenic pressures. In human-dominated landscapes where remnants of riparian vegetation give refuge to a diverse array of myrmecofauna, the protection of the few remaining and well-preserved riparian sites is essential for the long-term maintenance of biodiversity. PMID:26352255

  6. Mathematical modeling riparian vegetation zonation in semiarid conditions based on a transpiration index.

    NASA Astrophysics Data System (ADS)

    Real, Joaquin; Morales, Marco; Garcia, Alicia; Garofano, Virginia; Martinez-Capel, Francisco; Frances, Felix

    2010-05-01

    Initially riparian vegetation modeling was focused on the study of ecological patches without taking into account the interactive effects of structures and processes in between them (Tabacchi et al., 1998). One of the greatest challenges, when carrying out a riparian ecosystem restoration, is to understand the physical and ecological processes of a system and the interaction and feedback within these processes. Jorde (2002) pointed out the importance of addressing complex linkages between processes and biotic interactions in research and in the development of restoration projects over larger spatial and temporal scales in the future. According to Tabacchi et al. (2000), the water cycle in riparian zones depends on three important relations: the water absorption by the plants, water storage and atmospherical return by evaporation. During recent years a variety of ecological models have taken into account the changes in the plant species as consequence of changes in the environmental variables and hydrological alterations (Baptist, 2005; Braatne et al., 2002; Glenz, 2005; Hooke et al., 2005; Murphy et al., 2006). Most of these models are based on functional relationships between river hydrology and vegetation species or communities. In semiarid regions we make the hypothesis transpiration will be one of the key factors determining the riparian vegetation presence and therefore, we will not consider in our model other factors as recruitment, flood damages, etc. The objectives of this work are: firstly to develop a model capable of simulating several riparian vegetation types which can be applied in a wide range of conditions across Mediterranean environments; and secondly to calibrate and to validate the model in several Mediterranean river stretches of the Iberian Peninsula, both in undisturbed and disturbed flow regimes. To achieve these objectives the following methodology has been applied. The model has been conceptualized as a static tank flow model based on the

  7. Optical Characteristics and Chemical Composition of Dissolved Organic Matter (DOM) from Riparian Soil by Using Excitation-Emission Matrix (EEM) Fluorescence Spectroscopy and Mass Spectrometry.

    PubMed

    Wang, Yulai; Yang, Changming; Zou, Limin; Cui, Hengzhao

    2015-05-01

    Understanding the quantity and quality of soil dissolved organic matter (DOM) in riparian buffer zones is critical for explaining the biogeochemical processes of soil DOM in river ecosystems. Here, we investigated the dissolved organic carbon, fluorescent DOM (FDOM), and DOM molecules from riparian soils on Chongming Island in eastern China. Simultaneously, the soil DOM was extensively characterized in terms of the total aromaticity index (TAI) and several optical indices. The excitation (Ex)-emission (Em) matrix parallel factor analysis results showed that two humic-like components were present (Ex/Em = 283(364)/454 nm; 337/410 nm), a fulvic-like component (Ex/Em = 241/426 nm) and a microbial degradation component (Ex/Em = 295/382 nm). The humic-like and fulvic-like substances were the main components in the riparian soil FDOM, accounting for ~90% of the FDOM. Mass spectrometry provided more detailed information for the soil DOM molecules. Six chemical fractions, amino acids, carbonyl compounds, fatty acids, lipids, proteins and sugars, were identified using liquid chromatography with quadrupole time-of-flight mass spectrometry. Lipids, proteins, and carbonyl compounds were dominant in the soil DOM, accounting for >85% of the detected molecules (m/z < 1000). Significant differences were observed between the quantities of the six soil DOM chemical fractions at the different sampling locations. Discriminant molecules verified the hypothesis that the chemical soil DOM fractions varied with the land use of the adjacent watersheds. The TAI for the soil DOM could provide more reliable information regarding the biogeochemical processes of DOM. The carbonyl compounds and lipid fractions controlled this index. Overall, the optical indices and TAI values can improve our understanding of soil DOM quality; however, the optical indices did not provide quantitative evidence regarding the sources or properties of the soil DOM. The observations from this study provided detailed

  8. Evaporative losses from a common reed-dominated peachleaf willow and cottonwood riparian plant community

    NASA Astrophysics Data System (ADS)

    Kabenge, Isa; Irmak, Suat

    2012-09-01

    Our study is one of the first to integrate and apply within-canopy radiation physics parameters and scaling-up leaf-level stomatal resistace (rL) to canopy resistance (rc) approach to quantify hourly transpiration (TRP) rates of individual riparian plant species—common reed (Phragmites australis), peachleaf willow (Salix amygdaloides), and cottonwood (Populus deltoides)— in a mixed riparian plant community in the Platte River Basin in central Nebraska. Two experimental years (2009 and 2010) were contrasted by warmer air temperature and presence of flood water in 2010. The seasonal average rc values for common reed, peachleaf willow, and cottonwood in 2009 were 76, 70, and 107 s m-1, respectively. The corresponding rc values in the flood year (2010) were 70, 66, and 105 s m-1 for the same species, respectively. In 2009, the seasonal total TRP for common reed, peachleaf willow, and cottonwood were 483, 522, and 431 mm, respectively. Corresponding TRP values in 2010 were greater as 550, 655, and 496 mm, respectively. In 2009, TRP accounted for 64% of ETa during June-September, and the proportion varied between 41% and 69% for most of the season. In 2010, TRP accounted for 61% of ETa during June-September, and the proportion varied between 41% and 65% for most of the season. The average surface evaporation rate of the riparian zone was 0.81 mm d-1 in 2009 and 1.70 mm d-1 in 2010. Seasonal evaporation was 160 mm in 2009 and 312 mm in 2010. The study provides a basis for understanding the dynamics of transpiration for riparian vegetation in response to the environmental conditions and provides valuable water use data for more complete water balance analyses by accounting for the water use of riparian vegetation species.

  9. Riparian buffer strips as a multifunctional management tool in agricultural landscapes: introduction.

    PubMed

    Stutter, Marc I; Chardon, Wim J; Kronvang, Brian

    2012-01-01

    Catchment riparian areas are considered key zones to target mitigation measures aimed at interrupting the movement of diffuse substances from agricultural land to surface waters. Hence, unfertilized buffer strips have become a widely studied and implemented "edge of field" mitigation measure assumed to provide an effective physical barrier against nitrogen (N), phosphorus (P), and sediment transfer. To ease the legislative process, these buffers are often narrow mandatory strips along streams and rivers, across different riparian soil water conditions, between bordering land uses of differing pollution burdens, and without prescribed buffer management. It would be easy to criticize such regulation for not providing the opportunity for riparian ecosystems to maximize their provision for a wider range of ecosystem goods and services. The scientific basis for judging the best course of action in designing and placing buffers to enhance their multifunctionality has slowly increased over the last five years. This collection of papers aims to add to this body of knowledge by giving examples of studies related to riparian buffer management and assessment throughout Europe. This introductory paper summarizes discussion sessions and 13 selected papers from a workshop held in Ballater, UK, highlighting research on riparian buffers brought together under the EU COST Action 869 knowledge exchange program. The themes addressed are (i) evidence of catchment- to national-scale effectiveness, (ii) ecological functioning linking terrestrial and aquatic habitats, (iii) modeling tools for assessment of effectiveness and costs, and (iv) process understanding enabling management and manipulation to enhance pollutant retention in buffers. The combined understanding led us to consider four principle key questions to challenge buffer strip research and policy.

  10. Effects of riparian timber harvesting on instream habitat and fish assemblages in northern Minnesota streams

    USGS Publications Warehouse

    Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric; Schlesser, Nicholas

    2010-01-01

    Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m2 ha−1 or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m2 ha−1 may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.

  11. Riparian litter inputs to streams in the central Oregon Coast Range

    USGS Publications Warehouse

    Hart, Stephanie K.; Hibbs, David E.; Perakis, Steven S.

    2013-01-01

    Riparian-zone vegetation can influence terrestrial and aquatic food webs through variation in the amount, timing, and nutritional content of leaf and other litter inputs. We investigated how riparian-forest community composition, understory density, and lateral slope shaped vertical and lateral litter inputs to 16 streams in the Oregon Coast Range. Riparian forests dominated by deciduous red alder delivered greater annual vertical litter inputs to streams (504 g m−2 y−1) than did riparian forests dominated by coniferous Douglas-fir (394 g m−2 y−1). Deciduous forests also contributed greater lateral litter inputs per meter of stream bank on one side (109 g m−1 y−1) than did coniferous forests (63 g m−1 y−1). Total litter inputs from deciduous forests exceeded those from coniferous forests most strongly in November, coincident with an autumn peak in litter inputs. Lateral litter inputs contributed most to total inputs during winter in both forest types. Annual lateral litter movement increased with slope at deciduous sites, but only in spring/summer months at coniferous sites. Neither experimental removal of understory vegetation nor installation of mesh fences to block downslope litter movement affected lateral litter inputs to streams, suggesting that ground litter moves <5 m downslope annually. N concentrations of several litter fractions were higher at deciduous sites and, when combined with greater litter amounts, yielded twice as much total litter N flux to streams in deciduous than coniferous sites. The presence of red alder in riparian forests along many small streams of the deeply incised and highly dendritic basins of the Oregon Coast Range enhances total fluxes and seasonality of litter delivery to both terrestrial and aquatic food webs in this region and complements the shade and large woody debris provided by large coniferous trees.

  12. Flood-deposited wood debris and its contribution to heterogeneity and regeneration in a semi-arid riparian landscape.

    PubMed

    Pettit, Neil E; Naiman, Robert J

    2005-09-01

    We investigated whether large woody debris (LWD) piles create nodes of environmental resources that contribute to the recovery of riparian vegetation and that also augment the heterogeneity and resilience of the riverine system. River and riparian systems are typified by a large degree of heterogeneity and complex interactions between abiotic and biotic elements. Disturbance such as floods re-distribute the resources, such as LWD, and thereby add greater complexity to the system. We examined this issue on a semi-arid savanna river where approximately a 100-year return interval flood in 2000 uprooted vegetation and deposited substantial LWD. We investigated the micro-environment within the newly established LWD piles and compared this with conditions at adjacent reference sites containing no LWD. We found soil nutrient concentrations to be significantly higher in LWD piles compared with the reference plots (total N +19%, available P +51%, and total C +36%). Environmental variables within LWD piles and reference sites varied with landscape position in the river-riparian landscape and with LWD pile characteristics. Observed differences were generally between piles located in the terrestrial and riparian areas as compared to piles located on the macro-channel floor. After 3 years the number and cover of woody species were significantly higher when associated with LWD piles, regardless of landscape position or pile type. We conclude that LWD piles formed after large floods act as resource nodes by accumulating fine sediments and by retaining soil nutrients and soil moisture. The subsequent influence of LWD deposition on riparian heterogeneity is discerned at several spatial scales including within and between LWD piles, across landscape positions and between channel types. LWD piles substantially influence the initial developmental of riparian vegetation as the system regenerates following large destructive floods. PMID:16025355

  13. Ground-water surface-water interactions and long-term change in riverine riparian vegetation in the southwestern United States

    USGS Publications Warehouse

    Webb, R.H.; Leake, S.A.

    2006-01-01

    Riverine riparian vegetation has changed throughout the southwestern United States, prompting concern about losses of habitat and biodiversity. Woody riparian vegetation grows in a variety of geomorphic settings ranging from bedrock-lined channels to perennial streams crossing deep alluvium and is dependent on interaction between ground-water and surface-water resources. Historically, few reaches in Arizona, southern Utah, or eastern California below 1530 m elevation had closed gallery forests of cottonwood and willow; instead, many alluvial reaches that now support riparian gallery forests once had marshy grasslands and most bedrock canyons were essentially barren. Repeat photography using more than 3000 historical images of rivers indicates that riparian vegetation has increased over much of the region. These increases appear to be related to several factors, notably the reduction in beaver populations by trappers in the 19th century, downcutting of arroyos that drained alluvial aquifers between 1880 and 1910, the frequent recurrence of winter floods during discrete periods of the 20th century, an increased growing season, and stable ground-water levels. Reductions in riparian vegetation result from agricultural clearing, excessive ground-water use, complete flow diversion, and impoundment of reservoirs. Elimination of riparian vegetation occurs either where high ground-water use lowers the water table below the rooting depth of riparian species, where base flow is completely diverted, or both. We illustrate regional changes using case histories of the San Pedro and Santa Cruz Rivers, which are adjacent watersheds in southern Arizona with long histories of water development and different trajectories of change in riparian vegetation.

  14. Geophysical Evidence to Link Terrestrial Insect Diversity and Groundwater Availability in Non-Riparian Ecosystems

    NASA Astrophysics Data System (ADS)

    Pehringer, M.; Carr, G.; Long, H.; Parsekian, A.

    2015-12-01

    Wyoming, the third driest state in the United States, is home to a high level of biodiversity. In many cases, ecosystems are dependent on the vast systems of water resting just below the surface. This groundwater supports a variety of organisms that live far from surface water and its surrounding riparian zone, where more than 70% of species reside. In order to observe the correlation of groundwater presence and biodiversity in non-riparian ecosystems, a study was conducted to look specifically at terrestrial insect species linked to groundwater in Bighorn National Forest, WY. It was hypothesized that the more groundwater present, the greater the diversity of insects would be. Sample areas were randomly selected in non-riparian zones and groundwater was evaluated using a transient electromagnetic (TEM) geophysical instrument. Electrical pulses were transmitted through a 40m by 40m square of wire to measure levels of resistivity from near the surface to several hundred meters below ground. Pulses are echoed back to the surface and received by a smaller 10m by 10m square of wire, and an even smaller 1m by 1m square of wire set inside the larger transmitting wire. An insect population and species count was then conducted within the perimeter set by the outer transmitting wire. The results were not as hypothesized. More inferred groundwater below the surface resulted in a smaller diversity of species. Inversely, the areas with a smaller diversity held a larger total population of terrestrial insects.

  15. Salmon nutrients are associated with the phylogenetic dispersion of riparian flowering-plant assemblages.

    PubMed

    Hurteau, Leslie A; Mooers, Arne Ø; Reynolds, John D; Hocking, Morgan D

    2016-02-01

    A signature of nonrandom phylogenetic community structure has been interpreted as indicating community assembly processes. Significant clustering within the phylogenetic structure of a community can be caused by habitat filtering due to low nutrient availability. Nutrient limitation in temperate Pacific coastal rainforests can be alleviated to some extent by marine nutrient subsidies introduced by migrating salmon, which leave a quantitative signature on the makeup of plant communities near spawning streams. Thus, nutrient-mediated habitat filtering could be reduced by salmon nutrients. Here, we ask how salmon abundance affects the phylogenetic structure of riparian flowering plant assemblages across 50 watersheds in the Great Bear Rainforest of British Columbia, Canada. Based on a regional pool of 60 plant species, we found that assemblages become more phylogenetically dispersed and species poor adjacent to streams with higher salmon spawning density. In contrast, increased phylogenetic clumping and species richness was seen in sites with low salmon density, with steeper slopes, further from the stream edge, and within smaller watersheds. These observations are all consistent with abiotic habitat filtering and biotic competitive exclusion acting together across local and landscape-scale gradients in nutrient availability to structure assembly of riparian flowering plants. In this case, rich salmon nutrients appear to release riparian flowering-plant assemblages from the confines of a low-nutrient habitat filter that drives phylogenetic clustering. PMID:27145619

  16. Riparian Buffer Project : Annual Report for the Period April 1, 2001 to March 31, 2002.

    SciTech Connect

    Wasco County Soil and Water Conservation District

    2002-01-01

    This project implements riparian buffer systems in the Mid-Columbia, addressing limiting factors identified in the Fifteen mile Subbasin Summary, June 30, 2000. The project is providing the technical planning support needed to implement at least 36 riparian buffer system contracts on approximately 872 acres covering an estimated 40 miles of anadromous fish streams over a three year period. In the first year of implementation, 26 buffer contracts were established on 25-26 miles of stream. This nearly doubled the annual goal. Buffer widths averaged 83 ft. on each side of the stream. Implementation included prescribed plantings, fencing, and related practices. Actual implementation costs, lease payments, and maintenance costs are borne by existing USDA programs: Conservation Reserve and Conservation Reserve Enhancement Programs. The lease period of each contract may vary between 10 to 15 years. During this year the average was 14.5 years. The total value of contracts established this year is $1,491,235 compared with $64,756 in BPA contract costs to provide the technical support needed to get the contracts implemented. This project provides technical staffing to conduct assessments and develop plans to help keep pace with the growing backlog of potential riparian buffer projects. Word of mouth from satisfied customers has brought in many new sign-ups during the year. More than half of the contracts this year have been done in the Hood and Fifteen mile sub-basins with additional contracts in adjacent sub-basins.

  17. Scale perspectives on avian diversity in western riparian ecosystems

    USGS Publications Warehouse

    KNopf, Fritz L.; Samson, Fred B.

    1994-01-01

    Conservation of riparian vegetation in western North America has, in part, emphasized providing habitats for a locally diverse avifauna. Site diversity, especially relative to the number of species present, is generally high within riparian avifaunas. Between-habitat diversity changes across a watershed, with riparian species assemblages differing most from upland assemblages at the highest and lowest elevations. This pattern can be attributed to enhanced avian movements within the riparian vegetation. The corridors for bird movements, in turn, facilitate faunal mixing on a broader scale, influencing regional diversity within landscapes. Riparian ecosystems are viewed as connectors of forests across fragmental landscapes. In western settings, however, they are highly linearized forests transecting watersheds between upland associations of high elevations and very different associations at lower elevations. Regionally, riparian vegetation represents linear islands that are internally both floristically and faunistically dynamic rather than mere bridges of homogeneous vegetation in landscape networks. The significance of riparian vegetation as habitat for western birds has been defined primarily at the local level. Conservation activities favoring site diversity are short-sighted, however, and could have severe consequences for unique elements of riparian avifaunas. Conservation actions must evaluate how local activities alter potential dispersal opportunities for ecological-generalist versus riparian-obligate species. Maintaining the character and integrity of riparian avifaunas requires planning from regional and continental perspectives.

  18. Scott river riparian woodland revegetation demonstration project, FY 1994. Final report

    SciTech Connect

    Jopson, T.M.

    1995-04-01

    The purpose of this project was to demonstrate techniques that could lead to the successful restoration of riparian woodland along the Scott River and elsewhere at a reasonable cost. Three sites were selected for the projects on the basis of need for restoration (i.e. the lack of vegetation), the applicability of the site as a demonstration area (how typical of other areas it was), exclusionary fencing, and the willingness of the landowner to participate. Three woody plant species, black cottonwood (Populus nigra), willow (Salix sp.) and Ponderosa pine (Pinus ponderosa) were chosen for planting on the site. These species were known to occur naturally in the riparian zone of the river, were relatively easy to grow in the available time, would produce a variety of habitats when mature, and would grow tall enough to provide shade for the water.

  19. Mechanisms of nutrient attenuation in a subsurface flow riparian wetland.

    PubMed

    Casey, R E; Taylor, M D; Klaine, S J

    2001-01-01

    Riparian wetlands are transition zones between terrestrial and aquatic environments that have the potential to serve as nutrient filters for surface and ground water due to their topographic location. We investigated a riparian wetland that had been receiving intermittent inputs of NO3- and PO4(3-) during storm runoff events to determine the mechanisms of nutrient attenuation in the wetland soils. Few studies have shown whether infrequent pulses of NO3- are sufficient to maintain substantial denitrifying communities. Denitrification rates were highest at the upstream side of the wetland where nutrient-rich runoff first enters the wetland (17-58 microg N2O-N kg soil(-1) h(-1)) and decreased further into the wetland. Carbon limitation for denitrification was minor in the wetland soils. Samples not amended with dextrose had 75% of the denitrification rate of samples with excess dextrose C. Phosphate sorption isotherms suggested that the wetland soils had a high capacity for P retention. The calculated soil PO4(3-) concentration that would yield an equilibrium aqueous P04(3-) concentration of 0.05 mg P L(-1) was found to be 100 times greater than the soil PO4(3-) concentration at the time of sampling. This indicated that the wetland could retain a large additional mass of PO4(3-) without increasing the dissolved P04(3-) concentrations above USEPA recommended levels for lentic waters. These results demonstrated that denitrification can be substantial in systems receiving pulsed NO3- inputs and that sorption could account for extensive PO4(3-) attenuation observed at this site.

  20. Object-based class modelling for multi-scale riparian forest habitat mapping

    NASA Astrophysics Data System (ADS)

    Strasser, Thomas; Lang, Stefan

    2015-05-01

    Object-based class modelling allows for mapping complex, hierarchical habitat systems. The riparian zone, including forests, represents such a complex ecosystem. Forests within riparian zones are biologically high productive and characterized by a rich biodiversity; thus considered of high community interest with an imperative to be protected and regularly monitored. Satellite earth observation (EO) provides tools for capturing the current state of forest habitats such as forest composition including intermixture of non-native tree species. Here we present a semi-automated object based image analysis (OBIA) approach for the mapping of riparian forests by applying class modelling of habitats based on the European Nature Information System (EUNIS) habitat classifications and the European Habitats Directive (HabDir) Annex 1. A very high resolution (VHR) WorldView-2 satellite image provided the required spatial and spectral details for a multi-scale image segmentation and rule-base composition to generate a six-level hierarchical representation of riparian forest habitats. Thereby habitats were hierarchically represented within an image object hierarchy as forest stands, stands of homogenous tree species and single trees represented by sunlit tree crowns. 522 EUNIS level 3 (EUNIS-3) habitat patches with a mean patch size (MPS) of 12,349.64 m2 were modelled from 938 forest stand patches (MPS = 6868.20 m2) and 43,742 tree stand patches (MPS = 140.79 m2). The delineation quality of the modelled EUNIS-3 habitats (focal level) was quantitatively assessed to an expert-based visual interpretation showing a mean deviation of 11.71%.

  1. Hydrologic assessment of a riparian section along Boulder Creek near Boulder, Colorado, September 1989-September 1991

    USGS Publications Warehouse

    Kimbrough, Robert

    1995-01-01

    Native woody riparian species, primarily plains cottonwood (Populus fremontii), are regenerating at less than historical rates along Boulder Creek, a regulated stream near Boulder, Colorado. Loss of native riparian habitats might cause a decline in numbers of some native wildlife species. Previous studies have indicated that streamflow regulation can adversely affect native riparian vegetation reproduction. Surface- and ground-water data were collected from September 1989 to September 1991 along a riparian section of Boulder Creek to assist ecologists in assessing woody plant-recruitment characteristics. Annual mean streamflows in Boulder Creek at Cottonwood Grove of 34.5 cubic feet per second for water year 1990 (October 1, 1989- September 30, 1990) and 34.1 cubic feet per second for water year 1991 were 53 percent less than a site on Boulder Creek about 5 miles upstream from the study area. Diversions dating from 1882 caused most of the decrease. The alluvial aquifer in the study area averaged 5 feet in thickness and consisted of gravel- to cobble-size particles derived from crystalline rock of Precambrian age. The direction of ground-water movement was similar to the direction of streamflow. Ground-water movement in the northeastern part of the grove was affected by a pond constructed at a lower elevation than the stream channel. Water levels in the alluvial aquifer adjacent to the stream pre- dominantly were affected by stream stage, whereas farther from the channel, ground-water levels were affected by other processes such as evapotrans- piration, infiltration, and recharge from urban runoff.

  2. Denitrification and a nitrogen budget of created riparian wetlands.

    PubMed

    Batson, Jacqulyn A; Mander, Ulo; Mitsch, William J

    2012-01-01

    Riparian wetland creation and restoration have been proposed to mediate nitrate-nitrogen (NO-N) pollution from nonpoint agricultural runoff. Denitrification by anaerobic microbial communities in wetland soils is believed to be one of the main sinks for NO-N as it flows through wetlands. Denitrification rates were quantified using an in situ acetylene inhibition technique at 12 locations in three wetland/riverine sites at the Olentangy River Wetland Research Park, Columbus, Ohio for 1 yr. Sites included two created flow-through experimental wetlands and one bottomland forest/river-edge site. Points were spatially distributed at inflows, center, and outflows of the two wetlands to include permanently flooded open water, intermittently flooded transitions, and upland. Annual denitrification rates (median [mean]) were significantly higher ( < 0.001) in permanently flooded zones of the wetlands (266 [415] μg NO-N m h) than in shallower transition zones (58 [37.5] μg NO-N m h). Median wetland transition zone denitrification rates did not differ significantly ( ≥ 0.05) from riverside or upland sites. Denitrification rates peaked in spring; for the months of April through June, median denitrification rates ranged from 240 to 1010 μg NO-N m h in the permanently flooded zones. A N mass balance analysis showed that surface water flux of N was reduced by 57% as water flowed through the wetland, but only about 3.5% of the N inflow was permanently removed through denitrification. Most N was probably lost through groundwater seepage. Comparison with denitrification rates measured previously in these wetlands suggests that these rates have remained steady over the past 4 to 5 yr.

  3. State wetlands and riparian area protection programs

    NASA Astrophysics Data System (ADS)

    Steiner, Frederick; Pieart, Scott; Cook, Edward; Rich, Jacqueline; Coltman, Virginia

    1994-03-01

    The protection of wetlands and riparian areas has emerged as an important environmental planning issue. In the United States, several federal and state laws have been enacted to protect wetlands and riparian areas. Specifically, the federal Clean Water Act includes protection requirements in Sections 301 and 303 for state water quality standards, Section 401 for state certification of federal actions (projects, permits, and licenses), and Section 404 for dredge and fill permits. The Section 401 water quality state certification element has been called the “sleeping giant” of wetlands protection because it empowers state officials to veto or condition federally permitted or licensed activities that do not comply with state water quality standards. State officials have used this power infrequently. The purpose of this research was to analyze the effectiveness of state wetland and riparian programs. Contacts were established with officials in each state and in the national and regional offices of key federal agencies. Based on interviews and on a review of federal and state laws, state program effectiveness was analyzed. From this analysis, several problems and opportunities facing state wetland protection efforts are presented.

  4. Southern Arizona riparian habitat: Spatial distribution and analysis

    NASA Technical Reports Server (NTRS)

    Lacey, J. R.; Ogden, P. R.; Foster, K. E.

    1975-01-01

    The objectives of this study were centered around the demonstration of remote sensing as an inventory tool and researching the multiple uses of riparian vegetation. Specific study objectives were to: (1) map riparian vegetation along the Gila River, San Simon Creek, San Pedro River, Pantano Wash, (2) determine the feasibility of automated mapping using LANDSAT-1 computer compatible tapes, (3) locate and summarize existing mpas delineating riparian vegetation, (4) summarize data relevant to Southern Arizona's riparian products and uses, (5) document recent riparian vegetation changes along a selected portion of the San Pedro River, (6) summarize historical changes in composition and distribution of riparian vegetation, and (7) summarize sources of available photography pertinent to Southern Arizona.

  5. Nesting ecology of Greater Sandhill Cranes (Grus canadensis tabida) in riparian and palustrine wetlands of eastern Idaho

    USGS Publications Warehouse

    McWethy, D.B.; Austin, J.E.

    2009-01-01

    Little information exists on breeding Greater Sandhill Cranes (Grus canadensis tabida) in riparian wetlands of the Intermountain West. We examined the nesting ecology of Sandhill Cranes associated with riparian and palustrine wetlands in the Henry's Fork Watershed in eastern Idaho in 2003. We located 36 active crane nests, 19 in riparian wetlands and 17 in palustrine wetlands. Nesting sites were dominated by rushes (Juncus spp.), sedges (Carex spp.), Broad-leaved Cattail (Typha latifolia) and willow (Salix spp.), and adjacent foraging areas were primarily composed of sagebrush (Artemisia spp.), cinquefoil (Potentilla spp.),Rabbitbrush (Ericameria bloomeri) bunch grasses, upland forbs, Quaking Aspen (Populus tremuloides) and cottonwood (Populus spp.). Mean water depth surrounding nests was 23 cm (SD = 22). A majority of nests (61%) were surrounded by vegetation between 3060 cm, 23% by vegetation 60 cm in height. We were able to determine the fate of 29 nests, of which 20 were successful (69%). Daily nest survival was 0.986 (95% LCI 0.963, UCI 0.995), equivalent to a Mayfield nest success of 0.654 (95% LCI 0.324, UCI 0.853). Model selection favored models with the covariates vegetation type, vegetation height, and water depth. Nest survival increased with increasing water depth surrounding nest sites. Mean water depth was higher around successful nests (30 cm, SD = 21) than unsuccessful nests (15 cm, SD 22). Further research is needed to evaluate the relative contribution of cranes nesting in palustrine and riparian wetlands distributed widely across the Intermountain West.

  6. Floral ecology and insect visitation in riparian Tamarix sp. (saltcedar)

    USGS Publications Warehouse

    Andersen, D.C.; Nelson, S.M.

    2013-01-01

    Climate change projections for semiarid and arid North America include reductions in stream discharge that could adversely affect riparian plant species dependent on stream-derived ground water. In order to better understand this potential impact, we used a space-for-time substitution to test the hypotheses that increasing depth-to-groundwater (DGW) is inversely related to Tamarix sp. (saltcedar) flower abundance (F) and nectar production per flower (N). We also assessed whether DGW affected the richness or abundance of insects visiting flowers. We examined Tamarix floral attributes and insect visitation patterns during 2010 and 2011 at three locations along a deep DWG gradient (3.2–4.1 m) on a floodplain terrace adjacent to Las Vegas Wash, an effluent-dominated Mojave Desert stream. Flower abundance and insect visitation patterns differed between years, but no effect from DGW on either F or N was detected. An eruption of a novel non-native herbivore, the splendid tamarisk weevil (Coniatus splendidulus), likely reduced flower production in 2011.

  7. Does stream flow structure woody riparian vegetation in subtropical catchments?

    PubMed

    James, Cassandra S; Mackay, Stephen J; Arthington, Angela H; Capon, Samantha J; Barnes, Anna; Pearson, Ben

    2016-08-01

    The primary objective of this study was to test the relevance of hydrological classification and class differences to the characteristics of woody riparian vegetation in a subtropical landscape in Queensland, Australia. We followed classification procedures of the environmental flow framework ELOHA - Ecological Limits of Hydrologic Alteration. Riparian surveys at 44 sites distributed across five flow classes recorded 191 woody riparian species and 15, 500 individuals. There were differences among flow classes for riparian species richness, total abundance, and abundance of regenerating native trees and shrubs. There were also significant class differences in the occurrence of three common tree species, and 21 indicator species (mostly native taxa) further distinguished the vegetation characteristics of each flow class. We investigated the influence of key drivers of riparian vegetation structure (climate, depth to water table, stream-specific power, substrate type, degree of hydrologic alteration, and land use) on riparian vegetation. Patterns were explained largely by climate, particularly annual rainfall and temperature. Strong covarying drivers (hydrology and climate) prevented us from isolating the independent influences of these drivers on riparian assemblage structure. The prevalence of species considered typically rheophytic in some flow classes implies a more substantial role for flow in these classes but needs further testing. No relationships were found between land use and riparian vegetation composition and structure. This study demonstrates the relevance of flow classification to the structure of riparian vegetation in a subtropical landscape, and the influence of covarying drivers on riparian patterns. Management of environmental flows to influence riparian vegetation assemblages would likely have most potential in sites dominated by rheophytic species where hydrological influences override other controls. In contrast, where vegetation assemblages are

  8. Does stream flow structure woody riparian vegetation in subtropical catchments?

    PubMed

    James, Cassandra S; Mackay, Stephen J; Arthington, Angela H; Capon, Samantha J; Barnes, Anna; Pearson, Ben

    2016-08-01

    The primary objective of this study was to test the relevance of hydrological classification and class differences to the characteristics of woody riparian vegetation in a subtropical landscape in Queensland, Australia. We followed classification procedures of the environmental flow framework ELOHA - Ecological Limits of Hydrologic Alteration. Riparian surveys at 44 sites distributed across five flow classes recorded 191 woody riparian species and 15, 500 individuals. There were differences among flow classes for riparian species richness, total abundance, and abundance of regenerating native trees and shrubs. There were also significant class differences in the occurrence of three common tree species, and 21 indicator species (mostly native taxa) further distinguished the vegetation characteristics of each flow class. We investigated the influence of key drivers of riparian vegetation structure (climate, depth to water table, stream-specific power, substrate type, degree of hydrologic alteration, and land use) on riparian vegetation. Patterns were explained largely by climate, particularly annual rainfall and temperature. Strong covarying drivers (hydrology and climate) prevented us from isolating the independent influences of these drivers on riparian assemblage structure. The prevalence of species considered typically rheophytic in some flow classes implies a more substantial role for flow in these classes but needs further testing. No relationships were found between land use and riparian vegetation composition and structure. This study demonstrates the relevance of flow classification to the structure of riparian vegetation in a subtropical landscape, and the influence of covarying drivers on riparian patterns. Management of environmental flows to influence riparian vegetation assemblages would likely have most potential in sites dominated by rheophytic species where hydrological influences override other controls. In contrast, where vegetation assemblages are

  9. Multiscale remote sensing analysis to monitor riparian and upland semiarid vegetation

    NASA Astrophysics Data System (ADS)

    Nguyen, Uyen

    The health of natural vegetation communities is of concern due to observed changes in the climatic-hydrological regime and land cover changes particularly in arid and semiarid regions. Monitoring vegetation at multi temporal and spatial scales can be the most informative approach for detecting change and inferring causal agents of change and remediation strategies. Riparian communities are tightly linked to annual stream hydrology, ground water elevations and sediment transport. These processes are subject to varying magnitudes of disturbance overtime and are candidates for multi-scale monitoring. My first research objective focused on the response of vegetation in the Upper San Pedro River, Arizona, to reduced base flows and climate change. I addressed the correlation between riparian vegetation and hydro-climate variables during the last three decades in one of the remaining undammed rivers in the southwestern U.S. Its riparian forest is threatened by the diminishing base flows, attributed by different studies either to increases in evapotranspiration (ET) due to conversion of grasslands to mesquite shrublands in the adjacent uplands, or to increased regional groundwater pumping to serve growing populations in surrounding urban areas and or to some interactions of those causes. Landsat 5 imagery was acquired for pre- monsoon period, when riparian trees had leafed out but before the arrival of summer monsoon rains in July. The result has showed Normalized Difference Vegetation Index (NDVI) values from both Landsat and Moderate Resolution Imaging Spectrometer (MODIS) had significant decreases which positively correlated to river flows, which decreased over the study period, and negatively correlated with air temperatures, which have increased by about 1.4°C from 1904 to the present. The predictions from other studies that decreased river flows could negatively impact the riparian forest were supported by this study. The pre-monsoon Normalized Different Vegetation

  10. Improving riparian wetland conditions based on infiltration and drainage behavior during and after controlled flooding

    NASA Astrophysics Data System (ADS)

    Russo, Tess A.; Fisher, Andrew T.; Roche, James W.

    2012-04-01

    SummaryWe present results of an observational and modeling study of the hydrologic response of a riparian wetland to controlled flooding. The study site is located in Poopenaut Valley, Yosemite National Park (USA), adjacent to the Tuolumne River. This area is flooded periodically by releases from the Hetch Hetchy Reservoir, and was monitored during one flood sequence to assess the relative importance of inundation versus groundwater rise in establishing and maintaining riparian wetland conditions, defined on the basis of a minimum depth and duration of soil saturation, and to determine how restoration benefits might be achieved while reducing total flood discharge. Soil moisture data show how shallow soils were wetted by both inundation and a rising water table as the river hydrograph rose repeatedly during the controlled flood. The shallow groundwater aquifer under wetland areas responded quickly to conditions in the adjacent river, demonstrating a good connection between surface and subsurface regimes. The observed soil drainage response helped to calibrate a numerical model that was used to test scenarios for controlled flood releases. Modeling of this groundwater-wetland system suggests that inundation of surface soils is the most effective mechanism for developing wetland conditions, although an elevated water table helps to extend the duration of soil saturation. Achievement of wetland conditions can be achieved with a smaller total flood release, provided that repeated cycling of higher and lower river elevations is timed to benefit from the characteristic drainage behavior of wetland soils. These results are robust to modest variations in the initial water table elevation, as might result from wetter or dryer conditions prior to a flood. However, larger changes to initial water table elevation, as could be associated with long term climate change or drought conditions, would have a significant influence on wetland development. An ongoing controlled flooding

  11. Riparian restoration using physical manipulation and natural seedfall

    USGS Publications Warehouse

    Auble, G.T.

    1999-01-01

    In many arid landscapes, riparian sites are the only places wet enough to support trees. The vertical structure of trees and shrubs is critical to many riparian habitat and aesthetic values (Brinson et al. 1981). Thus, woody vegetation is often an important objective and success measure for riparian restoration. Effective restoration planning depends on some underlying model of how the ecosystem functions– what variables determine its condition, how it became degraded, and how it will respond to alternative management actions. Vegetation within a riparian system is dependent on site conditions and the processes that determine those conditions.

  12. Development and application of multi-proxy indices of land use change for riparian soils in southern New England, USA.

    PubMed

    Ricker, M C; Donohue, S W; Stolt, M H; Zavada, M S

    2012-03-01

    Understanding the effects of land use on riparian systems is dependent upon the development of methodologies to recognize changes in sedimentation related to shifts in land use. Land use trends in southern New England consist of shifts from forested precolonial conditions, to colonial and agrarian land uses, and toward modern industrial-urban landscapes. The goals of this study were to develop a set of stratigraphic indices that reflect these land use periods and to illustrate their applications. Twenty-four riparian sites from first- and second-order watersheds were chosen for study. Soil morphological features, such as buried surface horizons (layers), were useful to identify periods of watershed instability. The presence of human artifacts and increases in heavy metal concentration above background levels, were also effective indicators of industrial-urban land use periods. Increases and peak abundance of non-arboreal weed pollen (Ambrosia) were identified as stratigraphic markers indicative of agricultural land uses. Twelve 14C dates from riparian soils indicated that the rise in non-arboreal pollen corresponds to the start of regional deforestation (AD 1749 +/- 56 cal yr; mean +/- 2 SD) and peak non-arboreal pollen concentration corresponds to maximum agricultural land use (AD 1820 +/- 51 cal yr). These indices were applied to elucidate the impact of land use on riparian sedimentation and soil carbon (C) dynamics. This analysis indicated that the majority of sediment and soil organic carbon (SOC) stored in regional riparian soils is of postcolonial origins. Mean net sedimentation rates increased -100-fold during postcolonial time periods, and net SOC sequestration rates showed an approximate 200-fold increase since precolonial times. These results suggest that headwater riparian zones have acted as an effective sink for alluvial sediment and SOC associated with postcolonial land use. PMID:22611849

  13. Perspectives on screening winter-flood-tolerant woody species in the riparian protection forests of the three gorges reservoir.

    PubMed

    Yang, Fan; Wang, Yong; Chan, Zhulong

    2014-01-01

    The establishment of riparian protection forests in the Three Gorges Reservoir (TGR) is an ideal measure to cope with the eco-environmental problems of the water-level fluctuation zone (WLFZ). Thus, the information for screening winter-flood-tolerant woody plant species is useful for the recovery and re-establishment of the riparian protection forests in the TGR WLFZ. Therefore, we discussed the possibilities of constructing and popularizing riparian protection forests in the TGR WLFZ from several aspects, including the woody plant species distribution in the WLFZ, the survival rate analyses of suitable candidate woody species under controlled flooding conditions, the survival rate investigation of some woody plant species planted in the TGR WLFZ, and the physiological responses of some woody plant species during the recovery stage after winter floods. The results of woody species investigation showed that most woody plant species that existed as annual seedlings in the TGR WLFZ are not suitable candidates for the riparian protection forests. However, arbor species (e.g., Salix matsudana, Populus×canadensis, Morus alba, Pterocarya stenoptera, Taxodium ascendens, and Metasequoia glyptostroboides) and shrub species (e.g., Salix variegata, Distylium chinensis, Lycium chinense, Myricaria laxiflora, and Rosa multiflora) might be considered suitable candidates for the riparian protection forests in the TGR WLFZ by survival rate analyses under controlled winter flooding conditions, and survival rate investigations of woody plant species planted in the TGR WLFZ, respectively. Physiological analyses showed that P.×canadensis, M. alba, L. chinense, and S. variegata could develop specific self-repairing mechanisms to stimulate biomass accumulation and carbohydrate synthesis via the increases in chlorophyll pigments and photosynthesis during recovery after winter floods. Our results suggested these woody plant species could endure the winter flooding stress and recover well

  14. Perspectives on Screening Winter-Flood-Tolerant Woody Species in the Riparian Protection Forests of the Three Gorges Reservoir

    PubMed Central

    Yang, Fan; Wang, Yong; Chan, Zhulong

    2014-01-01

    The establishment of riparian protection forests in the Three Gorges Reservoir (TGR) is an ideal measure to cope with the eco-environmental problems of the water-level fluctuation zone (WLFZ). Thus, the information for screening winter-flood-tolerant woody plant species is useful for the recovery and re-establishment of the riparian protection forests in the TGR WLFZ. Therefore, we discussed the possibilities of constructing and popularizing riparian protection forests in the TGR WLFZ from several aspects, including the woody plant species distribution in the WLFZ, the survival rate analyses of suitable candidate woody species under controlled flooding conditions, the survival rate investigation of some woody plant species planted in the TGR WLFZ, and the physiological responses of some woody plant species during the recovery stage after winter floods. The results of woody species investigation showed that most woody plant species that existed as annual seedlings in the TGR WLFZ are not suitable candidates for the riparian protection forests. However, arbor species (e.g., Salix matsudana, Populus×canadensis, Morus alba, Pterocarya stenoptera, Taxodium ascendens, and Metasequoia glyptostroboides) and shrub species (e.g., Salix variegata, Distylium chinensis, Lycium chinense, Myricaria laxiflora, and Rosa multiflora) might be considered suitable candidates for the riparian protection forests in the TGR WLFZ by survival rate analyses under controlled winter flooding conditions, and survival rate investigations of woody plant species planted in the TGR WLFZ, respectively. Physiological analyses showed that P.×canadensis, M. alba, L. chinense, and S. variegata could develop specific self-repairing mechanisms to stimulate biomass accumulation and carbohydrate synthesis via the increases in chlorophyll pigments and photosynthesis during recovery after winter floods. Our results suggested these woody plant species could endure the winter flooding stress and recover well

  15. Measuring and Monitoring HydroBiogeochemical Flux in a Forested Riparian Floodplain of the Missouri Ozarks

    NASA Astrophysics Data System (ADS)

    Chinnasamy, P.; Hubbart, J. A.

    2009-12-01

    Forested riparian buffers play a vital role in protecting riparian ecosystems from natural and anthropogenic disturbances. Quantifying effective reach and catchment scale buffer designs is critical to achieve economic and riparian wetland natural resource sustainability. Advances in management of riparian wetlands require innovative reach-scale experimental studies and subsequent improvements in riparian modeling. Riparian recommended best management practices (BMPs) in Missouri (MO) have not been validated. Studies are therefore warranted to describe subsurface interactions between the stream, hyporheic zone (HZ), and adjoining riparian wetland/floodplain. Within the HZ groundwater discharge through highly permeable Karst geology can dramatically affect water quality. The following research is on-going in the Baskett Research and Education Area (BREA), a 9.17 km2 preserved wildland watershed located 8 km east of Ashland, in the Ozark border region of south-central MO. The climate at BREA is generally described as warm, humid, and continental, with mean January and August temperatures of -2.4 °C and 24.5 °C, respectively, and 1,022 mm mean annual precipitation. Limestone geology of Ordovician and Mississippian age underlies the BREA with dominant soils of Weller silt loam and Clinkenbeard clay loam. Vegetation at the BREA consists of northern and southern division oak dominated hickory forests. BREA offers a distinct opportunity to study wildland watershed processes to validate contemporary best management practices (BMP) in MO. To quantify hydrobiogeochemical flux, spatial and temporal (3 water years) variability in stream water temperatures, key nutrients (NO3, P, K, NH3) and hyporheic exchange are being monitored. Key hydrologic variables approaching a mass balance, plus groundwater monitoring (via piezometric arrays) are being studied. Results (beginning summer and fall 2009) will provide the necessary information to quantify the relationships between

  16. Ranking European regions as providers of structural riparian corridors for conservation and management purposes

    NASA Astrophysics Data System (ADS)

    Clerici, Nicola; Vogt, Peter

    2013-04-01

    Riparian zones are of utmost importance in providing a wide range of ecological and societal services. Among these, their role in maintaining landscape connectivity through ecological corridors for animals and plants is of major interest from a conservation and management perspective. This paper describes a methodology to identify European regions as providers of structural riparian corridors, and to rank them with reference to conservation priority. Physical riparian connectors among core habitat patches are identified through a recent segmentation technique, the Morphological Spatial Pattern Analysis. A multi-scale approach is followed by considering different edge distances to identify core and peripheral habitats for a range of hypothetical species. The ranking is performed using a simple set of indices that take into account the degree of environmental pressure and the presence of land protection schemes. An example for environmental reporting is carried out using European administrative regions and major rivers to summarize indices value. The approach is based on freely available software and simple metrics which can be easily reproduced in a GIS environment.

  17. The Role of Road Corridors on Riparian Vegetation and Stream Ecosystem Dynamics.

    NASA Astrophysics Data System (ADS)

    Crowl, T.; Heartsill-Scalley, T.; Covich, A. P.; Hein, C. L.

    2005-05-01

    Stream ecosystems are dependent on organic material from the riparian zone as a major energy source for the food web. Leaf litter (organic matter) entering streams is processed by a combination of physical and biological mechanisms. In temperate streams, microbial conditioning is important for detrital processing. Much less is known in tropical systems, especially those dominated by large macro-consumers such as decapods. There is also variation among species in terms of processing rates that are explained by nutritional value, chemical defenses and palatability. These traits are a function of plant life history. If riparian species are being significantly altered through invasions by exotic species along road corridors, then we can expect changes in detrital processing rates and ultimately, ecosystem function. As part of a biocomplexity project in Puerto Rico, we are quantifying the changes to species composition and trait-mediated decomposition and foodweb dynamics. Where roads are constructed, exotic invasives include Spathodea, Bambusa, Syzigium and a various grasses. Because of the chemical defenses and their high nutritional value, decomposition rates on these species is much higher than for native riparian species. The increased breakdown rates may `accelerate' ecosystem processes and either enhance or destabilize existing food web linkages.

  18. Early Response of Soil Properties and Function to Riparian Rainforest Restoration

    PubMed Central

    Gageler, Rose; Bonner, Mark; Kirchhof, Gunnar; Amos, Mark; Robinson, Nicole; Schmidt, Susanne; Shoo, Luke P.

    2014-01-01

    Reforestation of riparian zones is increasingly practiced in many regions for purposes of biodiversity conservation, bank stabilisation, and improvement in water quality. This is in spite of the actual benefits of reforestation for recovering underlying soil properties and function remaining poorly understood. Here we compare remnant riparian rainforest, pasture and reforestation plantings aged 2–20 years in an Australian subtropical catchment on ferrosols to determine the extent to which reforestation restores key soil properties. Of the nine soil attributes measured (total nitrogen, nitrate and ammonium concentrations, net nitrification and ammonification rates, organic carbon, bulk density, fine root biomass and water infiltration rates), only infiltration rates were significantly lower in pasture than remnant riparian rainforest. Within reforestation plantings, bulk density decreased up to 1.4-fold and infiltration rates increased up to 60-fold with time post-reforestation. Our results suggest that the main outcome of belowground processes of early reforestation is the recovery of the soils' physical structure, with potential beneficial ecosystem services including reduced runoff, erosion and associated sediment and nutrient loads in waterways. We also demonstrate differential impacts of two commonly planted tree species on a subset of soil properties suggesting that preferential planting of select species could accelerate progress on specific restoration objectives. PMID:25117589

  19. Modeling the Channel/Floodplain Interface: The Influence of Riparian Vegetation on Mass and Momentum Exchange

    NASA Astrophysics Data System (ADS)

    Stone, M. C.

    2013-12-01

    The objective of this research was to improve understanding of the impacts of riparian vegetation on mass and momentum flux between the main channel and the floodplain. Numerical investigations were carried out on five sites within three rivers in New Mexico, USA. Vegetation characteristics were varied to represent different riparian scenarios ranging from no vegetation to dense understory. The sedimentation and river hydraulics in two dimensions (SRH-2D) model was applied to simulate hydrodynamic conditions. The model was modified to include two algorithms for simulating a dynamic hydraulic roughness in the riparian zone. Thus resistive forces were represented as a function of vegetation characteristics and hydrodynamic condition. The results provide insights into the processes of mass and momentum transfer at the channel/floodplain interface. As expected, an increase in vegetation density produced enhanced momentum exchange. However, a threshold was reached beyond which the momentum exchange peaked and then dropped. This threshold was the results of low floodplain velocities producing very little resistive force due to low drag. Future work will focus on unsteady investigations and laboratory and field verification studies.

  20. Early response of soil properties and function to riparian rainforest restoration.

    PubMed

    Gageler, Rose; Bonner, Mark; Kirchhof, Gunnar; Amos, Mark; Robinson, Nicole; Schmidt, Susanne; Shoo, Luke P

    2014-01-01

    Reforestation of riparian zones is increasingly practiced in many regions for purposes of biodiversity conservation, bank stabilisation, and improvement in water quality. This is in spite of the actual benefits of reforestation for recovering underlying soil properties and function remaining poorly understood. Here we compare remnant riparian rainforest, pasture and reforestation plantings aged 2-20 years in an Australian subtropical catchment on ferrosols to determine the extent to which reforestation restores key soil properties. Of the nine soil attributes measured (total nitrogen, nitrate and ammonium concentrations, net nitrification and ammonification rates, organic carbon, bulk density, fine root biomass and water infiltration rates), only infiltration rates were significantly lower in pasture than remnant riparian rainforest. Within reforestation plantings, bulk density decreased up to 1.4-fold and infiltration rates increased up to 60-fold with time post-reforestation. Our results suggest that the main outcome of belowground processes of early reforestation is the recovery of the soils' physical structure, with potential beneficial ecosystem services including reduced runoff, erosion and associated sediment and nutrient loads in waterways. We also demonstrate differential impacts of two commonly planted tree species on a subset of soil properties suggesting that preferential planting of select species could accelerate progress on specific restoration objectives. PMID:25117589

  1. Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.

    PubMed

    Egger, Gregory; Politti, Emilio; Lautsch, Erwin; Benjankar, Rohan; Gill, Karen M; Rood, Stewart B

    2015-09-15

    River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change. PMID:26160662

  2. Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.

    PubMed

    Egger, Gregory; Politti, Emilio; Lautsch, Erwin; Benjankar, Rohan; Gill, Karen M; Rood, Stewart B

    2015-09-15

    River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change.

  3. Early response of soil properties and function to riparian rainforest restoration.

    PubMed

    Gageler, Rose; Bonner, Mark; Kirchhof, Gunnar; Amos, Mark; Robinson, Nicole; Schmidt, Susanne; Shoo, Luke P

    2014-01-01

    Reforestation of riparian zones is increasingly practiced in many regions for purposes of biodiversity conservation, bank stabilisation, and improvement in water quality. This is in spite of the actual benefits of reforestation for recovering underlying soil properties and function remaining poorly understood. Here we compare remnant riparian rainforest, pasture and reforestation plantings aged 2-20 years in an Australian subtropical catchment on ferrosols to determine the extent to which reforestation restores key soil properties. Of the nine soil attributes measured (total nitrogen, nitrate and ammonium concentrations, net nitrification and ammonification rates, organic carbon, bulk density, fine root biomass and water infiltration rates), only infiltration rates were significantly lower in pasture than remnant riparian rainforest. Within reforestation plantings, bulk density decreased up to 1.4-fold and infiltration rates increased up to 60-fold with time post-reforestation. Our results suggest that the main outcome of belowground processes of early reforestation is the recovery of the soils' physical structure, with potential beneficial ecosystem services including reduced runoff, erosion and associated sediment and nutrient loads in waterways. We also demonstrate differential impacts of two commonly planted tree species on a subset of soil properties suggesting that preferential planting of select species could accelerate progress on specific restoration objectives.

  4. Riparian Bird Communities as Indicators of Human Impacts Along Mediterranean Streams

    NASA Astrophysics Data System (ADS)

    Larsen, Stefano; Sorace, Alberto; Mancini, Laura

    2010-02-01

    Riparian areas link aquatic and terrestrial habitats, supporting species-rich bird communities, which integrate both terrestrial and aquatic processes. For this reason, inclusion of riparian birds in stream bioassessment could add to the information currently provided by existing programs that monitor aquatic organisms. To assess if bird community metrics could indicate stream conditions, we sampled breeding birds in the riparian zone of 37 reaches in 5 streams draining watersheds representing a gradient of agricultural intensity in central Italy. As a more direct indicator of water quality, stream macroinvertebrates were also sampled for computation of the Italian Extended Biotic Index (IBE). An anthropogenic index was calculated within 1 km of sampled reaches based on satellite-derived land-use classifications. Predictive models of macroinvertebrate integrity based on land-use and avian metrics were compared using an information-theoretic approach (AIC). We also determined if stream quality related to the detection of riverine species. Apparent bird species diversity and richness peaked at intermediate levels of land-use modification, but increased with IBE values. Water quality did not relate to the detection of riverine species as a guild, but two species, the dipper Cinclus cinclus and the grey wagtail Motacilla cinerea, were only observed in reaches with the highest IBE values. Small-bodied insectivorous birds and arboreal species were detected more often in reaches with better water quality and in less modified landscapes. In contrast, larger and granivorous species were more common in disturbed reaches. According to the information-theoretic approach, the best model for predicting water quality included the anthropogenic index, bird species diversity, and an index summarizing the trophic structure of the bird community. We conclude that, in combination with landscape-level information, the diversity and trophic structure of riparian bird communities could

  5. Mechanisms driving the seasonality of catchment scale nitrate export: Evidence for riparian ecohydrologic controls

    NASA Astrophysics Data System (ADS)

    Duncan, Jonathan M.; Band, Lawrence E.; Groffman, Peter M.; Bernhardt, Emily S.

    2015-06-01

    Considerable variability in the seasonal patterns of stream water nitrate (NO3-) has been observed in forested watersheds throughout the world. While many forested headwater catchments exhibit winter and early spring peaks in NO3- concentrations, several watersheds have peak concentrations during the summer months. Pond Branch, a headwater catchment in Maryland monitored for over 10 years, exhibits recurrent and broad summer peaks in both NO3- concentrations and watershed export. Higher NO3- export from June to September is particularly surprising, given that these summer months typically have the year's lowest discharge. A key challenge is identifying the source(s) of NO3- and the mechanism(s) by which it is transported to the watershed outlet during the summer. In this study, we assessed multiple hypotheses (not mutually exclusive) that could account for the seasonal trend including proximal controls of groundwater-surface water interactions, instream processes, and riparian groundwater-N cycling interactions, as well as two distal controls: geochemical weathering and senescence of riparian vegetation. A combination of long-term weekly and limited duration high-frequency sensor data reveals the importance of riparian ecohydrologic processes during base flow. In this watershed, patterns of seasonal stream water NO3- concentrations and fluxes depend fundamentally on interactions between groundwater dynamics and nitrogen (N) cycling in the riparian zone. Groundwater tables control nitrification-denitrification dynamics as well as hydrologic transport. Our results suggest that in many watersheds, a more sophisticated exploration of NO3- production and NO3- transport mechanisms is required to identify critical points in the landscape and over time that disproportionately drive patterns of watershed NO3- export.

  6. SNAG AND LARGE WOODY DEBRIS DYNAMICS IN RIPARIAN FORESTS

    EPA Science Inventory

    Important components of riparian forests are snags and streamside large woody debris (LWD) because they are functional in maintaining water quality and providing habitat for numerous plants and animals. To effectively manage riparian forests, it is important to understand the dy...

  7. PATTERNS OF TREE DOMINANCE IN CONIFEROUS RIPARIAN FORESTS

    EPA Science Inventory

    This research quantified patterns of riparian tree dominance in western Oregon, USA and then compared the observed patterns with the expected patterns defined from the literature. Research was conducted at 110 riparian sites located on private and public lands. The field sites we...

  8. Suspended sediment control and water quality conservation through riparian vegetation:

    NASA Astrophysics Data System (ADS)

    Pavanelli, D.; Cavazza, C.; Correggiari, S.

    2009-04-01

    monitored. The problem of controlling the river suspended sediment concentration can be tackled by increasing the riparian vegetation able to hold back the ground eroded by the slopes, but it is necessary to know where the critical zones are. The aim of the work is to propose a method allow us to detect the risk of soil erosion areas near the river and the functionality of existing riparian vegetation along river as buffers / filters towards the eroded soil from the hill slopes. The proposed methodology is supposed has been designed for water pollution control from suspended solids, pollutants and nutrients coming from hills and an improvement of the quality of the river environment. The methodology was applied on the riparian vegetation of the Gaiana torrent where it was related to soil cover and erosion areas of the hillslope, thus correlating the impact of human activities. The Gaiana catchment area is 8.6 km2 and the mean altitude is 237 a.m.s.l., the average rainfall is of 784 mm.. It is a typical Apennines streams, about 35 km south of Bologna, Italy. The main trunk stream is 6 km long and the whole drainage network is organized in a dendritic pattern, typical of clayey lithology of the basins. The main erosion processes active in the area are caused by precipitation and surface runoff: sheet wash, concentrated water erosion and badlands watersheds (calanchi), which represent about 15% of the basin area. The vegetation of the Gaiana basin is constituted by crops (39%), woods (37%), rock outcrops(i.e. badlands)(15%), bushes (5%) and pastures(3%). The stages of the study are to spot critical areas made up of streambank and the eroded areas on the slopes near the river, with the support of aerial photos and satellite images, survey and a geographic information system. The Gaiana riparian vegetation map has been drawn and, on a strip buffer 200 metres wide along river, the Vegetation cover and the Geomorphology maps (scale 1:5000) has been drawn, after photogrammetric

  9. Enhanced transpiration by riparian buffer trees in response to advection in a humid temperate agricultural landscape

    USGS Publications Warehouse

    Hernandez-Santana, V.; Asbjornsen, H.; Sauer, T.; Isenhart, T.; Schilling, K.; Schultz, Ronald

    2011-01-01

    Riparian buffers are designed as management practices to increase infiltration and reduce surface runoff and transport of sediment and nonpoint source pollutants from crop fields to adjacent streams. Achieving these ecosystem service goals depends, in part, on their ability to remove water from the soil via transpiration. In these systems, edges between crop fields and trees of the buffer systems can create advection processes, which could influence water use by trees. We conducted a field study in a riparian buffer system established in 1994 under a humid temperate climate, located in the Corn Belt region of the Midwestern U.S. (Iowa). The goals were to estimate stand level transpiration by the riparian buffer, quantify the controls on water use by the buffer system, and determine to what extent advective energy and tree position within the buffer system influence individual tree transpiration rates. We primarily focused on the water use response (determined with the Heat Ratio Method) of one of the dominant species (Acer saccharinum) and a subdominant (Juglans nigra). A few individuals of three additional species (Quercus bicolor, Betula nigra, Platanus occidentalis) were monitored over a shorter time period to assess the generality of responses. Meteorological stations were installed along a transect across the riparian buffer to determine the microclimate conditions. The differences found among individuals were attributed to differences in species sap velocities and sapwood depths, location relative to the forest edge and prevailing winds and canopy exposure and dominance. Sapflow rates for A. saccharinum trees growing at the SE edge (prevailing winds) were 39% greater than SE interior trees and 30% and 69% greater than NW interior and edge trees, respectively. No transpiration enhancement due to edge effect was detected in the subdominant J. nigra. The results were interpreted as indicative of advection effects from the surrounding crops. Further, significant

  10. A Groundwater flow Model of the Colorado River Delta to Support Riparian Habitat Restoration in Northern Mexico

    NASA Astrophysics Data System (ADS)

    Maddock, T.; Feirstein, E.; Baird, K. J.; Ajami, H.

    2007-05-01

    Quantification of groundwater flow dynamics and of the interactions among groundwater, surface water, and riparian vegetation, represent key components in the development of a balanced restoration plan for functional riparian ecosystems. A groundwater model was developed using MODFLOW 2000 to support of riparian restoration along the Colorado River Delta (Mexico: Baja California, Sonora). The Colorado River is widely recognized as one of the most modified and allocated rivers in the United States. For over 50 years flows into the Delta were severely reduced by the requirements of an emergent American West. However, subsequent to discharge pulses associated with the filling of Lake Powell, and the increased precipitation that accompanied ENSO cycles, a semblance of a native riparian habitat has been observed in the Delta since the 1980's (Zamora- Arroyo et al. 2001). The Delta and the riparian ecosystems of the region have since become the focus of a substantial body of multidisciplinary research. The research goal is to understand water table dynamics with particular attention to stream-aquifer interactions and groundwater behavior in the root zone. Groundwater reliant transpiration requirements were quantified for a set of dominant native riparian species using the Riparian ET (RIP-ET) package, an improved MODFLOW evapotranspiration (ET) module. RIP-ET simulates ET using a set of eco-physiologically based curves that more accurately represents individual plant species, reflects habitat complexity, and deals spatially with plant and water table distribution. When used in conjunction with a GIS based postprocessor (RIP-GIS.net), RIP-ET provides the basis for mapping groundwater conditions as they relate to user-specified plant groups. This explicit link between groundwater and plant sustainability is a driver to restoration design and allows for scenario modeling of various hydrologic conditions. Groundwater requirements determined in this research will be used by

  11. Classification of riparian forest species and health condition using multi-temporal and hyperspatial imagery from unmanned aerial system.

    PubMed

    Michez, Adrien; Piégay, Hervé; Lisein, Jonathan; Claessens, Hugues; Lejeune, Philippe

    2016-03-01

    Riparian forests are critically endangered many anthropogenic pressures and natural hazards. The importance of riparian zones has been acknowledged by European Directives, involving multi-scale monitoring. The use of this very-high-resolution and hyperspatial imagery in a multi-temporal approach is an emerging topic. The trend is reinforced by the recent and rapid growth of the use of the unmanned aerial system (UAS), which has prompted the development of innovative methodology. Our study proposes a methodological framework to explore how a set of multi-temporal images acquired during a vegetative period can differentiate some of the deciduous riparian forest species and their health conditions. More specifically, the developed approach intends to identify, through a process of variable selection, which variables derived from UAS imagery and which scale of image analysis are the most relevant to our objectives.The methodological framework is applied to two study sites to describe the riparian forest through two fundamental characteristics: the species composition and the health condition. These characteristics were selected not only because of their use as proxies for the riparian zone ecological integrity but also because of their use for river management.The comparison of various scales of image analysis identified the smallest object-based image analysis (OBIA) objects (ca. 1 m(2)) as the most relevant scale. Variables derived from spectral information (bands ratios) were identified as the most appropriate, followed by variables related to the vertical structure of the forest. Classification results show good overall accuracies for the species composition of the riparian forest (five classes, 79.5 and 84.1% for site 1 and site 2). The classification scenario regarding the health condition of the black alders of the site 1 performed the best (90.6%).The quality of the classification models developed with a UAS-based, cost-effective, and semi-automatic approach

  12. Classification of riparian forest species and health condition using multi-temporal and hyperspatial imagery from unmanned aerial system.

    PubMed

    Michez, Adrien; Piégay, Hervé; Lisein, Jonathan; Claessens, Hugues; Lejeune, Philippe

    2016-03-01

    Riparian forests are critically endangered many anthropogenic pressures and natural hazards. The importance of riparian zones has been acknowledged by European Directives, involving multi-scale monitoring. The use of this very-high-resolution and hyperspatial imagery in a multi-temporal approach is an emerging topic. The trend is reinforced by the recent and rapid growth of the use of the unmanned aerial system (UAS), which has prompted the development of innovative methodology. Our study proposes a methodological framework to explore how a set of multi-temporal images acquired during a vegetative period can differentiate some of the deciduous riparian forest species and their health conditions. More specifically, the developed approach intends to identify, through a process of variable selection, which variables derived from UAS imagery and which scale of image analysis are the most relevant to our objectives.The methodological framework is applied to two study sites to describe the riparian forest through two fundamental characteristics: the species composition and the health condition. These characteristics were selected not only because of their use as proxies for the riparian zone ecological integrity but also because of their use for river management.The comparison of various scales of image analysis identified the smallest object-based image analysis (OBIA) objects (ca. 1 m(2)) as the most relevant scale. Variables derived from spectral information (bands ratios) were identified as the most appropriate, followed by variables related to the vertical structure of the forest. Classification results show good overall accuracies for the species composition of the riparian forest (five classes, 79.5 and 84.1% for site 1 and site 2). The classification scenario regarding the health condition of the black alders of the site 1 performed the best (90.6%).The quality of the classification models developed with a UAS-based, cost-effective, and semi-automatic approach

  13. Moving window analysis and riparian boundary delineation on the Northern Plains of Kruger National Park, South Africa

    NASA Astrophysics Data System (ADS)

    Kröger, Robert; Khomo, Lesego M.; Levick, Shaun; Rogers, Kevin H.

    2009-09-01

    Landscapes commonly comprise of mosaics, patches and boundaries. Riparian boundaries are complex to delineate and characterize, with a multitude of variables available for delineation. Multiple methods exist for boundary delineation such as two-dimensional wombling, constrained classification techniques and discontinuity detection. One method that has proven to be reliable in boundary delineation with one-dimensional transect data is the moving split window (MSW) analysis. This study demonstrates the efficacy of MSW to delineate grass species turnover and environmental boundaries across two geologically dissimilar riparian zones in the Kruger National Park, South Africa. There are few studies that have delineated riparian boundaries of Kruger National Park, and none that have used the MSW analysis. MSW detects significant changes in dissimilarity indices of variables along gradients. Significant shifts in dissimilarity designate boundaries at various spatial scales dictated by window sizes. Significant boundaries emerge by altering window sizes, increasing quadrat width and removing infrequent herbaceous species. By utilizing these three methods, MSW background variance was reduced and riparian and wetland/upland boundaries were sharper and more easily defined.

  14. Seasonal differences in riparian consumer diet and insect communities in an Oregon Coast Range watershed food web.

    NASA Astrophysics Data System (ADS)

    Robillard, A.; Li, J.

    2005-05-01

    In riparian areas, terrestrial and aquatic habitats overlap creating zones where they interact as an aquatic-terrestrial interface. This coupling allows energy to move between systems and generates intertwining food webs. Thus, vertebrate riparian consumers, such as fish or birds, potentially have alternative prey from sources external to their habitats. The purpose of our study was to explore this reciprocal exchange in an alder dominated riparian forest of the Oregon Coast Range. Diet samples were collected from birds and fish in summer and fall 2003 with a suite of insect samples at Honeygrove Creek and two of its small tributaries. In a comparison of emerging aquatic insects and flying terrestrial insects during June and again in September, we detected seasonal differences in terrestrial and aquatic insects available to riparian consumers. Despite this availability of externally derived prey, fish depended more on resources derived from within their respective habitats during summer. Cutthroat trout (Oncorhynchus clarkii) and Coho salmon (Oncorhynchus kitsutch) ate more juvenile aquatic than adult aquatic or terrestrial insects. During fall, the same pattern was exhibited by Coho but Cutthroat trout appeared to consume a slightly greater number of terrestrial insects. The preliminary analysis of bird diet samples from commonly encountered species such as, Swainson's thrush, Song Sparrow, and Pacific-slope Flycatcher, showed more terrestrial derived prey in their diets than aquatic during the summer sampling season.

  15. Synchronous DOM and dissolved phosphorus release in riparian soil waters: linking water table fluctuations and biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Gruau, G.; Dupas, R.; Humbert, G.; GU, S.; Jeanneau, L.; Fovet, O.; Denis, M.; Gascuel-Odoux, C.; Jaffrezic, A.; Faucheux, M.; Gilliet, N.; Hamon, Y.; Petitjean, P.

    2015-12-01

    Riparian zones are often viewed as hot spots controlling N, C, P and Fe cycling and export in catchments. Groundwater and surface water flowpaths converge in these zones, and encounter the most reactive, organic-rich, uppermost soil horizons, while being at the same time zones in which soil moisture conditions temporarily fluctuate due to changes in water table depth, which can trigger biogeochemical processes. One well documented example is the process of denitrification which can remove N from riparian groundwater due to the anaerobic reduction of nitrate by soil organic matter. However, the role of riparian zones on the cycling of other nutrients such as dissolved organic matter (DOM) and dissolved P (DP) is much less well documented. In this study, we evaluated this role by using time series of DOM and DP concentrations obtained on the Kervidy-Naizin catchment, a temperate agricultural headwater catchment controlled by shallow groundwater. Over 2 years, groundwater DOM and DP were monitored fortnightly both in the riparian zones and at the bottom of hillslope domains. Two periods of synchronous DOM and DP release were evidenced, the first corresponding to the rise of the water table after the dry summer period, the second being concomitant of the installation of reducing conditions. The reductive dissolution of soil Fe oxyhydroxides initiated by the prolonged soil water saturation caused the second peak, a process which was, however, strongly temporarily and spatially variable at the catchment scale, being dependent on i) the local topographic slope and ii) the annual rainfall amount and frequency. As regard the first peak, it was due either to the flushing by the water table of DOM and DP accumulated during the summer period, or to the release of microbial DOM and DP due to microbial biomass killing by osmotic shock. This study argues for the existence of coupled and complex DOM and DP release processes in the riparian zones of shallow groundwater dominated

  16. Riparian vegetation controls on braided stream dynamics

    NASA Astrophysics Data System (ADS)

    Gran, Karen; Paola, Chris

    2001-12-01

    Riparian vegetation can significantly influence the morphology of a river, affecting channel geometry and flow dynamics. To examine the effects of riparian vegetation on gravel bed braided streams, we conducted a series of physical experiments at the St. Anthony Falls Laboratory with varying densities of bar and bank vegetation. Water discharge, sediment discharge, and grain size were held constant between runs. For each run, we allowed a braided system to develop, then seeded the flume with alfalfa (Medicago sativa), allowed the seeds to grow, and then continued the run. We collected data on water depth, surface velocity, and bed elevation throughout each run using image-based techniques designed to collect data over a large spatial area with minimal disturbance to the flow. Our results show that the influence of vegetation on overall river patterns varied systematically with the spatial density of plant stems. Vegetation reduced the number of active channels and increased bank stability, leading to lower lateral migration rates, narrower and deeper channels, and increased channel relief. These effects increased with vegetation density. Vegetation influenced flow dynamics, increasing the variance of flow direction in vegetated runs and increasing scour depths through strong downwelling where the flow collided with relatively resistant banks. This oblique bank collision also provides a new mechanism for producing secondary flows. We found it to be more important than the classical curvature-driven mechanism in vegetated runs.

  17. Alaska Adjacent Zone Safe Oil Transport and Revenue Sharing Act

    THOMAS, 113th Congress

    Sen. Begich, Mark [D-AK

    2013-01-31

    01/31/2013 Read twice and referred to the Committee on Energy and Natural Resources. (text of measure as introduced: CR S442-443) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  18. Post-wildfire natural restoration of riparian vegetation under stable hydro-geomorphic conditions: Nahal Grar, Northern Negev Desert, Israel

    NASA Astrophysics Data System (ADS)

    Egozi, Roey

    2015-04-01

    Wildfires are common to the Mediterranean region due to its defined dry season and long historical anthropogenic activities. Most of post-wildfire studies focus on mountains areas and thus refer to the hill-slope and its physical characteristics, e.g. morphology, length, angles, and aspect; its soil characteristics, e.g. type, infiltration rate, repellency; and its vegetative covers, e.g. planted trees vs. natural forest or native vs. exotic vegetation. In contrary there is very limited literature focusing on ecological and hydro-geomorphic aspects of post-wildfire of riparian vegetation / zone probably because of its negligible burned area relative to the spread of the fire, sometimes, over the whole watershed area. The limited literature on the topic is surprising given the fact that riparian vegetation zone has been acknowledged as a unique and important habitat supporting rich biodiversity. Herein we report on a wildfire event occurred on October 14th 2009 in a river section of Nahal Grar, Northern Negev Desert, Israel. The wildfire although was limited in its area (only 3 hectare) extended over the channel alone from bank to bank and thus provide a unique case study of completely burn down of riparian vegetation, mainly dense stands of Common Red (Australis Phragmites. Therefore a detailed study of this event provides an opportunity to tackle one of the basics questions which is determining the rate of natural restoration process that act at the immediate time after the wildfire event occurred. This type of information is most valuable to professional and stakeholders for better management of post-fire riparian zones. The results of the study suggest that under stable conditions, i.e. no major flood events occurred; disturbance time was short and ranged over 200 days due to, almost, immediate recovery of the riparian vegetation. However the re-growth of the riparian vegetation was not even but rather deferential and more complex then reported in the literature

  19. Contaminant transport in a three-zone wetland: Dispersion and ecological degradation

    NASA Astrophysics Data System (ADS)

    Luo, Jing; Huai, Wenxin; Wang, Ping

    2016-03-01

    To further understand the fate of contaminant transport in real waterways interacting with riparian buffers and adjacent aquatic vegetation, solute dispersion is analytically explored for three-zone wetland flows with usually high Péclet number in this paper. Ecological effects are also taken into account. Environmental dispersion is addressed independently via an exponential transformation of the basic formulation of mass transfer in the context of porous media flow. After rigorously generalizing Taylor's classical analysis, asymptotic analysis was used instead of the method of concentration moment or multi-scale analysis to simplify the examination. The mean concentration expansion base in Gill's method is adopted to model concentration deviations produced in the lateral-average operation. With a previously derived velocity profile, environmental dispersivity is obtained, effectively illustrating the effects of critical dimensionless parameters. Analytical expressions for evolution of the lateral mean concentration and critical length of the contaminant cloud are determined by combining the effects of both hydraulic dispersion and ecological degradation. An application example is provided to illustrate the evolution of contaminant cloud in terms of the critical length and duration with concentration greater than a given environmental standard level. Results show that for three-zone wetlands, the duration is clearly increased while the region affected by the contaminant cloud is slightly smaller than that for two-zone wetland flows.

  20. Fluvial ecosystem resilience and stability: the role of riparian vegetation

    NASA Astrophysics Data System (ADS)

    Corenblit, Dov; Steiger, Johannes

    2014-05-01

    Riparian vegetation impacts fluvial landform resistance and resilience. Here we analyse the spatial and temporal pattern of biogeomorphic equilibrium conditions within a high energy river system. We quantified rejuvenation and maturation of the biogeomorphic succession using a spatial explicit analysis based on aerial photographs at six dates between 1942 and 2000. The Mediterranean River Tech, France, was chosen because a catastrophic flood in 1940 (recurrence time > 100 years) nearly completely destroyed the riparian forest and thus rejuvenated the biogeomorphic succession, providing a reference state in 1942. Interactions between vegetation establishment and flood regime enhanced the replacement of the dense riparian forest removed in 1940 at the scale of the corridor. Following this major disturbance, the riparian landscape demonstrated a very high resilience related to a positive biogeomorphic feedback driven by pioneer riparian engineer plants trapping sediments. This positive feedback enhanced floodplain construction, vegetation succession and a non-linear increase in biogeomorphic stability. Biogeomorphic equilibrium (ratio between instable active tract and stabilised riparian margins) driven by the interplay of vegetation dynamics and hydrogeormorphic processes was reached thirty years after the catastrophic flood event. The results suggest the existence of abrupt transitions between alternative domains of stability and hysteresis cycles. Based on these findings we propose a topological model of riparian ecosystem resistance and resilience according to biogeomorphic feedbacks. Furthermore, the proposed model developed on the River Tech suggests that biogeomorphic feedbacks play a critical role for transitions between different fluvial styles which determine the evolutionary trajectories of rivers.

  1. Stereophotogrammetry in studies of riparian vegetation dynamics

    NASA Astrophysics Data System (ADS)

    Hortobagyi, Borbala; Vautier, Franck; Corenblit, Dov; Steiger, Johannes

    2014-05-01

    Riparian vegetation responds to hydrogeomorphic disturbances and also controls sediment deposition and erosion. Spatio-temporal riparian vegetation dynamics within fluvial corridors have been quantified in many studies using aerial photographs and GIS. However, this approach does not allow the consideration of woody vegetation growth rates (i.e. vertical dimension) which are fundamental when studying feedbacks between the processes of fluvial landform construction and vegetation establishment and succession. We built 3D photogrammetric models of vegetation height based on aerial argentic and digital photographs from sites of the Allier and Garonne Rivers (France). The models were realized at two different spatial scales and with two different methods. The "large" scale corresponds to the reach of the river corridor on the Allier river (photograph taken in 2009) and the "small" scale to river bars of the Allier (photographs taken in 2002, 2009) and Garonne Rivers (photographs taken in 2000, 2002, 2006 and 2010). At the corridor scale, we generated vegetation height models using an automatic procedure. This method is fast but can only be used with digital photographs. At the bar scale, we constructed the models manually using a 3D visualization on the screen. This technique showed good results for digital and also argentic photographs but is very time-consuming. A diachronic study was performed in order to investigate vegetation succession by distinguishing three different classes according to the vegetation height: herbs (<1 m), shrubs (1-4 m) or trees (>4 m). Both methods, i.e. automatic and manual, were employed to study the evolution of the three vegetation classes and the recruitment of new vegetation patches. A comparison was conducted between the vegetation height given by models (automatic and manual) and the vegetation height measured in the field. The manually produced models (small scale) were of a precision of 0.5-1 m, allowing the quantification of woody

  2. Combining Field and Laboratory Experiments in Order to Understand Interactions Between Flow, Sediment, Vegetation And Bank Erosion in Riparian Rehabilitation Works

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. F.; Gorrick, S.; Kalma, J.; Cook, N.; Outhet, D.; Raine, A.

    2005-12-01

    Riparian lands are important for maintaining viable ecosystems, improving water quality and reducing sediment yields. Yet, riparian lands are frequently neglected, degraded and poorly managed. In many Australian riverine zones clearing or grazing of native riparian vegetation has resulted in varying degrees of erosion, sedimentation and degradation of aquatic ecosystems. Reintroducing riparian vegetation is one of the preferred methods for improving bank stability, reducing bank erosion to natural rates and rehabilitating channels. The present research aims to explore how reintroduced riparian vegetation modifies the flow and sediment transport patterns and at the same time how the vegetation is affected by flow and sediment. Both field experimentation and laboratory studies will lead to basic understanding of the processes involved and will help the efficient design of plantings for riparian rehabilitation. In order to be able to reproduce the most important processes in a laboratory physical model, a field site with a relatively simple geometry has been selected for the study. The site is on a small sand bed stream in the Hunter Valley in NSW. The reach has a large radius bend with no riparian vegetation on the outer bank, where erosion occurs periodically. Reintroduction of vegetation is planned for October 2005, with pre and post monitoring stages running from March 2005 to August 2008. Laboratory physical modelling based on field characteristics and with varying flow discharges and plant arrangement will provide information to help develop, adapt and test quantitative models of flow dynamics, sediment transport and bank erosion incorporating the effects of vegetation. These results can then be used by river managers when they are developing rehabilitation strategies.

  3. 33 CFR 334.600 - TRIDENT Basin adjacent to Canaveral Harbor at Cape Canaveral Air Force Station, Brevard County...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Canaveral Harbor at Cape Canaveral Air Force Station, Brevard County, Fla.; danger zone. 334.600 Section 334... DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.600 TRIDENT Basin adjacent to Canaveral Harbor at Cape Canaveral Air Force Station, Brevard County, Fla.; danger zone. (a) The danger zone. From the west side...

  4. Nitrogen uptake in riparian plant communities across a sharp ecological boundary of salmon density

    PubMed Central

    Mathewson, DD; Hocking, MD; Reimchen, TE

    2003-01-01

    Background Recent studies of anadromous salmon (Oncorhynchus spp.) on the Pacific Coast of North America indicate an important and previously unrecognized role of salmonid nutrients to terrestrial biota. However, the extent of this uptake by primary producers and consumers and the influences on community structure remain poorly described. We examine here the contribution of salmon nutrients to multiple taxa of riparian vegetation (Blechnum spicant, Menziesii ferruginea, Oplopanax horridus, Rubus spectabilis, Vaccinium alaskaense, V. parvifolium, Tsuga heterophylla) and measure foliar δ15N, total %N and plant community structure at two geographically separated watersheds in coastal British Columbia. To reduce potentially confounding effects of precipitation, substrate and other abiotic variables, we made comparisons across a sharp ecological boundary of salmon density that resulted from a waterfall barrier to salmon migration. Results δ15N and %N in foliage, and %cover of soil nitrogen indicators differed across the waterfall barrier to salmon at each watershed. δ15N values were enriched by 1.4‰ to 9.0‰ below the falls depending on species and watershed, providing a relative contribution of marine-derived nitrogen (MDN) to vegetation of 10% to 60%. %N in foliar tissues was slightly higher below the falls, with the majority of variance occurring between vegetation species. Community structure also differed with higher incidence of nitrogen-rich soil indicator species below the waterfalls. Conclusions Measures of δ15N, %N and vegetation cover indicate a consistent difference in the riparian community across a sharp ecological boundary of salmon density. The additional N source that salmon provide to nitrogen-limited habitats appears to have significant impacts on the N budget of riparian vegetation, which may increase primary productivity, and result in community shifts between sites with and without salmon access. This, in turn, may have cascading ecosystem

  5. Downward Recharge Through Root Systems: has the Decline of Walnut Trees Altered the Hydrology of Semiarid Riparian Systems?

    NASA Astrophysics Data System (ADS)

    Hultine, K. R.; Williams, D. G.; Cable, W. L.; Burgess, S. S.

    2001-12-01

    Establishment and recruitment of walnut trees (Juglans spp.) has declined in semiarid riparian systems over the last century. Juglans spp. may have important impacts on hydrologic processes in these riparian systems, including the redistribution of shallow soil water to subsurface zones through their root systems. To assess the potential impact of Juglans on semiarid riparian systems, sap flow was measured on the tap root, lateral roots, and main stem of a single 10 yr old Arizona walnut tree (Juglans major) occurring in the Walnut Gulch Experimental Watershed in southeastern Arizona. Before the onset of the monsoon, almost all the water supplied to the main stem was from the taproot. After monsoon rains wetted surface soil layers, the contribution of water from the taproot declined to 65% of total tree sap flow, demonstrating a shift in water sources. Nocturnal reverse sap flow (downward hydraulic redistribution) was detected in the taproot and was on the order of 1000 g hr-1, or about one third of daytime sap flow toward the stem. Nocturnal reverse flow was also detected in the deep lateral roots; however, unlike the taproot, daytime sap flow declined to near zero. After severing all the shallow lateral roots, reverse flow in the deep roots ceased, and daytime sap flow in the taproot increased to 90% of total sap flow. These data show that Juglans may play a key role in the hydrology of semiarid riparian systems by redistributing a water from shallow to deep soil layers and reducing the potential for soil evaporation. The continued decline of Juglans may lead to significant changes in the hydrology and community structure of semiarid riparian systems where Juglans has not been replaced by species with similar root structural and functional traits.

  6. The influence of partial timber harvesting in riparian buffers on macroinvertebrate and fish communities in small streams in Minnesota, USA

    USGS Publications Warehouse

    Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric C.; Schlesser, Nicholas

    2010-01-01

    Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m2 ha−1 or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m2 ha−1 may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.

  7. Ecological barriers to gene flow between riparian and forest species of Ainsliaea (Asteraceae).

    PubMed

    Mitsui, Yuki; Nomura, Naofumi; Isagi, Yuji; Tobe, Hiroshi; Setoguchi, Hiroaki

    2011-02-01

    Understanding the role of habitat-associated adaptation in reducing gene flow resulting in population differentiation and speciation is a major issue in evolutionary biology. We demonstrate a significant role for habitat divergence in species isolation between two naturally hybridizing riparian and nonriparian plants, Ainsliaea faurieana and A. apiculata (Asteraceae), on Yakushima Island, Japan. By analyzing the fine-scale population structure at six sympatric sites, we found that variations in leaf shape, geography, light conditions, and genotype were strongly correlated across riverbank-forest transitions. No evidence of effective gene flow was found between the two species across the majority of the transition zones, although the NewHybrid clustering analysis confirmed interspecific hybridization. However, a relatively high level of gene flow was observed across one zone with a more diffuse ecotone and intermediate flooding and light conditions, possibly generated by human disturbances. These results suggest that the barriers to gene flow between the riparian and forest species are primarily ecological. Additional common garden experiments indicated that the two species are adaptively differentiated to contrasting flooding and light environments. Overall, our study suggests that adaptations to different habitats can lead to the formation of reproductive isolating barriers and the maintenance of distinct species boundaries.

  8. Monitoring of riparian vegetation response to flood disturbances using terrestrial photography

    NASA Astrophysics Data System (ADS)

    Džubáková, K.; Molnar, P.; Schindler, K.; Trizna, M.

    2015-01-01

    Flood disturbance is one of the major factors impacting riparian vegetation on river floodplains. In this study we use a high-resolution ground-based camera system with near-infrared sensitivity to quantify the immediate response of riparian vegetation in an Alpine, gravel bed, braided river to flood disturbance with the use of vegetation indices. Five large floods with return periods between 1.4 and 20.1 years in the period 2008-2011 in the Maggia River were analysed to evaluate patterns of vegetation response in three distinct floodplain units (main bar, secondary bar, transitional zone) and to compare the sensitivity of seven broadband vegetation indices. The results show both a negative (damage) and positive (enhancement) response of vegetation within 1 week following the floods, with a selective impact determined by pre-flood vegetation vigour, geomorphological setting and intensity of the flood forcing. The spatial distribution of vegetation damage provides a coherent picture of floodplain response in the three floodplain units. The vegetation indices tested in a riverine environment with highly variable surface wetness, high gravel reflectance, and extensive water-soil-vegetation contact zones differ in the direction of predicted change and its spatial distribution in the range 0.7-35.8%. We conclude that vegetation response to flood disturbance may be effectively monitored by terrestrial photography with near-infrared sensitivity, with potential for long-term assessment in river management and restoration projects.

  9. Monitoring of riparian vegetation response to flood disturbances using terrestrial photography

    NASA Astrophysics Data System (ADS)

    Džubáková, K.; Molnar, P.; Schindler, K.; Trizna, M.

    2014-03-01

    The distribution of riparian vegetation on river floodplains is strongly impacted by floods. In this study we use a new setup with high resolution ground-based cameras in an Alpine gravel bed braided river to quantify the immediate response of riparian vegetation to flood disturbance with the use of vegetation indices. Five largest floods with return periods between 1.4 and 20.1 years in the period 2008-2011 in the Maggia River were used to evaluate patterns of vegetation response in three distinct floodplain units (main bar, secondary bar, transitional zone) and to compare seven vegetation indices. The results show both negative (damage) and positive (enhancement) response of vegetation in a short period following floods, with a selective impact based on the hydrogeomorphological setting and the intensity of the flood forcing. The spatial distribution of vegetation damage provides a coherent picture of floodplain response in the three floodplain units with different flood stress. We show that the tested vegetation indices generally agree on the direction of predicted change and its spatial distribution. The average disagreement between indices was in the range 14.4-24.9% despite the complex environment, i.e. highly variable surface wetness, high gravel reflectance, extensive water-soil-vegetation contact zones. We conclude that immediate vegetation response to flood disturbance may be effectively monitored by terrestrial photography with potential for long-term assessment in river management and restoration projects.

  10. Riparian Vegetation Response to the March 2008 Short-Duration, High-Flow Experiment-Implications of Timing and Frequency of Flood Disturbance on Nonnative Plant Establishment Along the Colorado River Below Glen Canyon Dam

    USGS Publications Warehouse

    Ralston, Barbara E.

    2010-01-01

    Riparian plant communities exhibit various levels of diversity and richness. These communities are affected by flooding and are vulnerable to colonization by nonnative species. Since 1996, a series of three high-flow experiments (HFE), or water releases designed to mimic natural seasonal flooding, have been conducted at Glen Canyon Dam, Ariz., primarily to determine the effectiveness of using high flows to conserve sediment, a limited resource. These experiments also provide opportunities to examine the susceptibility of riparian plant communities to nonnative species invasions. The third and most recent HFE was conducted from March 5 to 9, 2008, and scientists with the U.S. Geological Survey's Grand Canyon Monitoring and Research Center examined the effects of high flows on riparian vegetation as part of the overall experiment. Total plant species richness, nonnative species richness, percent plant cover, percent organic matter, and total carbon measured from sediment samples were compared for Grand Canyon riparian vegetation zones immediately following the HFE and 6 months later. These comparisons were used to determine if susceptibility to nonnative species establishment varied among riparian vegetation zones and if the timing of the HFE affected nonnative plant establishment success. The 2008 HFE primarily buried vegetation rather than scouring it. Percent nonnative cover did not differ among riparian vegetation zones; however, in the river corridor affected by Glen Canyon Dam operations, nonnative species richness showed significant variation. For example, species richness was significantly greater immediately after and 6 months following the HFE in the hydrologic zone farthest away from the shoreline, the area that represents the oldest riparian zone within the post-dam riparian area. In areas closer to the river channel, tamarisk (Tamarix ramosissima X chinensis) seedling establishment occurred (<2 percent cover) in 2008 but not to the extent reported in

  11. Bottom-up factors influencing riparian willow recovery in Yellowstone National Park

    USGS Publications Warehouse

    Tercek, M.T.; Stottlemyer, R.; Renkin, R.

    2010-01-01

    After the elimination of wolves (Canis lupis L.) in the 1920s, woody riparian plant communities on the northern range of Yellowstone National Park (YNP) declined an estimated 50%. After the reintroduction of wolves in 19951996, riparian willows (Salix spp.) on YNP's northern range showed significant growth for the first time since the 1920s. However, the pace of willow recovery has not been uniform. Some communities have exceeded 400 cm, while others are still at pre-1995 levels of 250 cm max. height) willow sites where willows had escaped elk (Cervus elaphus L.) browsing with "short" willow sites that could still be browsed. Unlike studies that manipulated willow height with fences and artificial dams, we examined sites that had natural growth differences in height since the reintroduction of wolves. Tall willow sites had greater water availability, more-rapid net soil nitrogen mineralization, greater snow depth, lower soil respiration rates, and cooler summer soil temperatures than nearby short willow sites. Most of these differences were measured both in herbaceous areas adjacent to the willow patches and in the willow patches themselves, suggesting that they were not effects of varying willow height recovery but were instead preexisting site differences that may have contributed to increased plant productivity. Our results agree with earlier studies in experimental plots which suggest that the varying pace of willow recovery has been influenced by abiotic limiting factors that interact with top-down reductions in willow browsing by elk. ?? 2010 Western North American Naturalist.

  12. Establishment of a Riparian Buffer Strip for Alleviating Lake Eutrophication in Eastern China

    NASA Astrophysics Data System (ADS)

    Kennedy, M.; Naka, K.; Wu, Y.

    2014-12-01

    Riparian buffer strips are a growing conservation practice to control and mitigate non-point source pollution in Asia. China has seen rapid population growth and economic development in the last fifty years, coupled with a rapid increase in environmental pollution. Freshwater ecosystems have been particularly affected. Lake Tai, China's 3rd largest freshwater lake by volume, has seen a severe reduction in water quality since economic reforms began in the 1970s. Thus, significant interest for establishing riparian buffer strips in agricultural watersheds and freshwater systems within China is warranted. Eight 50 m x 20 m plots adjacent to a rice-phragmites farm were cleared within the Lake Tai basin region in Jiangsu Province, China. Seven plots were planted with either a Poplar hybrid, Cypress hybrid or a combination of both at varying densities, while the control and final plot allowed only for local vegetation to grow naturally. Soil, tree and groundwater samples were collected from all plots and analyzed for nitrogen and phosphorus concentrations. At this time in the study, results have been analyzed only for nitrogen concentrations using the ANOVA procedure. Results for both nitrogen and phosphorus concentrations are currently being analyzed.

  13. Species replacement by a nonnative salmonid alters ecosystem function by reducing prey subsidies that support riparian spiders.

    PubMed

    Benjamin, Joseph R; Fausch, Kurt D; Baxter, Colden V

    2011-10-01

    Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no studies have compared effects of wholesale replacement of a native by a nonnative species on subsidies that support consumers in adjacent habitats, nor quantified the magnitude of these effects. We examined whether streams invaded by nonnative brook trout (Salvelinus fontinalis) in two regions of the Rocky Mountains, USA, produced fewer emerging adult aquatic insects compared to paired streams with native cutthroat trout (Oncorhynchus clarkii), and whether riparian spiders that depend on these prey were less abundant along streams with lower total insect emergence. As predicted, emergence density was 36% lower from streams with the nonnative fish. Biomass of brook trout was higher than the cutthroat trout they replaced, but even after accounting for this difference, emergence was 24% lower from brook trout streams. More riparian spiders were counted along streams with greater total emergence across the water surface. Based on these results, we predicted that brook trout replacement would result in 6-20% fewer spiders in the two regions. When brook trout replace cutthroat trout, they reduce cross-habitat resource subsidies and alter ecosystem function in stream-riparian food webs, not only owing to increased biomass but also because traits apparently differ from native cutthroat