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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. Influence of riparian habitat on aquatic macroinvertebrate community colonization within riparian zones of agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about aquatic macroinvertebrate colonization of aquatic habitats within riparian zones of headwater streams in the Midwestern United States. Many headwater streams and their riparian habitats in this region have been modified for agricultural drainage. Riparian habitat modifications ...

  3. 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

  4. Small mammal habitat use within restored riparian habitats adjacent to channelized streams in Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and stream channelization has led to the development of gully erosion and further fragmenta...

  5. 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) ...

  6. 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.

  7. 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

  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. 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.

  10. Carbon storage of headwater riparian zones in an agricultural landscape

    PubMed Central

    2012-01-01

    Background In agricultural regions, streamside forests have been reduced in age and extent, or removed entirely to maximize arable cropland. Restoring and reforesting such riparian zones to mature forest, particularly along headwater streams (which constitute 90% of stream network length) would both increase carbon storage and improve water quality. Age and management-related cover/condition classes of headwater stream networks can be used to rapidly inventory carbon storage and sequestration potential if carbon storage capacity of conditions classes and their relative distribution on the landscape are known. Results Based on the distribution of riparian zone cover/condition classes in sampled headwater reaches, current and potential carbon storage was extrapolated to the remainder of the North Carolina Coastal Plain stream network. Carbon stored in headwater riparian reaches is only about 40% of its potential capacity, based on 242 MgC/ha stored in sampled mature riparian forest (forest > 50 y old). The carbon deficit along 57,700 km headwater Coastal Plain streams is equivalent to about 25TgC in 30-m-wide riparian buffer zones and 50 TgC in 60-m-wide buffer zones. Conclusions Estimating carbon storage in recognizable age-and cover-related condition classes provides a rapid way to better inventory current carbon storage, estimate storage capacity, and calculate the potential for additional storage. In light of the particular importance of buffer zones in headwater reaches in agricultural landscapes in ameliorating nutrient and sediment input to streams, encouraging the restoration of riparian zones to mature forest along headwater reaches worldwide has the potential to not only improve water quality, but also simultaneously reduce atmospheric CO2. PMID:22333213

  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. 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

  13. Focused Recharge in a Semi-arid Riparian Zone

    NASA Astrophysics Data System (ADS)

    Cook, A.; Geyer, T.; Shook, G.; Butler, J. J.; Whittemore, D.; Kluitenberg, G.

    2006-12-01

    Precipitation-induced recharge can be an important component of the water balance of semi-arid riparian zones. Recharge mechanisms were assessed as part of an ecohydrologic investigation at a site in a vegetated riparian zone along the Arkansas River in south-central Kansas (Larned Research Site). This site contains a network of shallow wells for water-table monitoring, neutron-probe access tubes for vadose-zone water content observations, a stream-gage station, and a weather station. Over the last four years, the Arkansas River has flowed at the site for less than four months, so the usual state of the channel is a dry, 20-30 m swath of coarse sand and gravel bounded by riparian-zone vegetation. An evaluation of water-table responses to precipitation at wells located at different distances from the channel found that recharge appears to be primarily occurring through the channel deposits. In the absence of rainfall, the general trend of ground water flow is from west to east. During and shortly after rain events, however, the hydraulic gradient changes and ground water flows outward from a mound underneath the channel. The peaks in the water-table hydrographs produced by precipitation events are lagged and attenuated with distance from the river channel in a manner very similar to what is observed when a flow event occurs in the river channel. These changes with distance from the channel appear to be independent of the depth to the water table. In addition, vadose-zone water content data show little evidence of vertical flow through the vadose zone in the vegetated riparian area in response to the precipitation. Variations in the dissolved solids content of ground water across the riparian area are consistent with recharge primarily occurring through the channel deposits.

  14. Atmospheric Delivery of Herbicides to Riparian Buffer Zones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have evaluated the ability of a riparian buffer to intercept herbicides from the air and deliver them directly by rainfall to a receiving stream in the buffer zone. The study was conducted over a four year period at a site in an agricultural watershed in Maryland. The rain collections included ...

  15. 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) ...

  16. 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.

  17. Ground water nitrate removal in subsoil of forested and mowed riparian buffer zones

    SciTech Connect

    Addy, K.L.; Gold, A.J.; Groffman, P.M.; Jacinthe, P.A.

    1999-05-01

    The authors studied two similar riparian sites in southern New England and examined ground water nitrate (NO{sub 3}{sup {minus}}-N) removal in the subsurface of mowed (i.e., herbaceous) vs. forested (i.e., woody) vegetation. Each site consisted of poorly drained, fine to medium sands and contained adjacent areas of mowed and forested vegetation. They dosed mesocosms with bromide and {sup 15}N labeled NO{sub 3}{sup {minus}}-N amended ground water to simulate the shallow ground water NO{sub 3}{sup {minus}}-N dynamics of riparian buffers zones. Mesocosms were composed of undisturbed, horizontal soil cores extracted from seasonally saturated subsoil. The authors observed substantial ground water NO{sub 3}{sup {minus}}-N removal and denitrification at all locations. Ground water NO{sub 3}{sup {minus}}-N removal rates were significantly correlated with carbon-enriched patches of organic matter. This correlation supports previous work that patches function as hotspots of microbial activity in the subsoil. Within each site, they found no significant difference in ground water NO{sub 3}{sup {minus}}-N removal rates in the subsoil of forested and mowed areas and they noted tree roots throughout the subsoil of the mowed areas. They found that ground water NO{sub 3}{sup {minus}}-N removal rates differed significantly between similar sites. They caution against ascribing specific ground water NO{sub 3}{sup {minus}}-N removal rates to different riparian aboveground vegetation types without recognizing the importance of site differences, e.g., water table dynamics, land use legacy and adjacent vegetation. Riparian zones composed of a mix of forested and mowed vegetation, common in agroforestry and suburban land uses, may remove substantial amounts of ground water NO{sub 3}{sup {minus}}-N.

  18. Relation between fish communities and riparian zone conditions at two spatial scales

    USGS Publications Warehouse

    Lee, K.E.; Goldstein, R.M.; Hanson, P.E.

    2001-01-01

     The relation offish community composition to riparian cover at two spatial scales was compared at 18 streams in the agricultural Minnesota River Basin. The two spatial scales were: (1) local riparian zone (a 200 meter wide buffer extending 2 to 3 kilometers upstream of the sampling reach); and (2) the upstream riparian zone (a 200 m wide buffer on the mainstem and all perennial tributaries upstream of the sampling reach). Analysis of variance indicated that streams with wooded-local riparian zones had greater fish species richness (means = 20 and 15, respectively) and Index of Biotic Integrity (IBI) scores (means = 40 and 26, respectively) than streams with open-local riparian zones. Streams with wooded-upstream riparian zones tended (were not statistically significant) to have greater numbers of species (means = 19 and 15, respectively) and IBI scores (means = 33 and 28, respectively) than streams with open-upstream riparian zones. There was no significant interaction between the riparian zone conditions at the two scales. This study suggests that maintenance of wooded riparian cover along streams could be effective in maintaining or improving fish community composition in streams draining heavily agricultural areas.

  19. 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...

  20. 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…

  1. Hydrogeologic and Biogeochemical Controls on the Fate and Transport of Nitrate and Pesticides in the Riparian Zone of Cow Castle Creek, South Carolina

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

    Riparian zones often contain large amounts of organic carbon and small concentrations of dissolved oxygen (DO) resulting in reducing conditions that favor removal of nitrate through denitrification, and in some cases pesticides. We investigated the transport and fate of nitrate, several commonly used pesticides, and selected metabolites at a farm in South Carolina adjacent to Cow Castle Creek. Sixteen shallow water-table wells were installed to map the water table and ground water was sampled using 7 multi-port wells installed at depths ranging from 0.5 to 10 m along a 1-km flow system bracketing several types of land use including a cornfield, pine forest, hay field, riparian forest, and the discharge area at Cow Castle Creek. Ground-water recharge dates, based on CFC age dating, were from the mid-to-late 1970s below the riparian zone and Cow Castle Creek indicating a maximum residence time of approximately 23-years. Organic carbon under the riparian zone was as high as 0.97 percent. DO concentrations were variable with the smallest values immediately under the riparian zone. Nitrate-nitrogen concentrations varied over the site from about 28 mg/L immediately down gradient of the cornfield to below detection (<0.05 mg/L) under the hayfield. Large decreases in nitrate-nitrogen were detected at the edge of the riparian zone and immediately below it. Nitrate concentrations initially increased with depth below the riparian zone then decreased again in deeper samples while beneath Cow Castle Creek they varied from 2.8 to 4.7 mg/L. Excess nitrogen gas concentrations, presumably derived from denitrification, varied from 1.4 to 4.1 mg/L under the riparian zone. Atrazine, metolachlor and their metabolites were the most commonly detected pesticides and were generally restricted to samples collected under and adjacent to the cornfield however, there were a few detections of atrazine, simazine, chlorpyrifos, and deethyl atrazine under and adjacent to the riparian zone. Flow

  2. 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...

  3. A SUSTAINABLE APPROACH TO NITRATE REDUCTION COMBINING A RIPARIAN ZONE WITH A STREAM DENITRIFYING BIOFILM

    EPA Science Inventory

    1) an optimum riparian zone design based on native or non-invasive plants to Southern Virginia and expected flow conditions and 2) an optimum biofilm design based on the ability to augment the riparian zone during inefficient times at the same conditions.

  4. 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...

  5. 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.

  6. Nitrogen fate across topographic gradients, from headwaters to riparian zones

    NASA Astrophysics Data System (ADS)

    Bock, E. M.; Fuka, D. R.; Easton, Z. M.

    2013-12-01

    Identifying where nitrogen transforming microbial process occur within the landscape is critical to understanding nitrogen dynamics on a regional to global scale. Although the connection between topography and the activity of soil nitrifiers and denitrifiers has been studied at the landscape scale, hillslope scale relationships are needed as a predictive tool to incorporate process-based nitrogen flux, as N2 and N2O emissions, into variable source hydrologic models, for predicting stream nutrient concentrations and ultimately catchment export. This study examines denitrification and N2O emission along topographic gradients, determined from direct measurement of dissolved N2 and N2O in soil water samples and measured from soil cores in situ. Additionally, denitrifying enzyme activity and microbial respiration, taken as the evolution of CO2, are recorded as indicators of potential microbial activity. Three transects are monitored from a hummocky pasture downslope through a riparian zone, where soil moisture conditions are dynamic, allowing the quantification of topographic controls under different soil moisture regimes. Previous studies have shown that topographic controls increase denitrification downslope because of enhanced down gradient nutrient supply via hydrologic flow paths. In addition, we incorporate the supply of soil moisture and/or nutrients during overbank flow as a driver of denitrification resulting from elevated discharge rather than the topographic gradient. Predicted stream flow and nitrogen concentration, based on models of variable source area hydrology, is then used to predict riparian denitrification in response to storm flow, modifying catchment export.

  7. Recovery of Nitrogen Pools and Processes in Degraded Riparian Zones in the Southern Appalachians

    EPA Science Inventory

    Soil nitrogen (N) cycling mechanisms were examined over a 4-year period in a restored mountain pasture riparian zone previously degraded by cattle. Chemical and physical effects of grazing were separated by comparing the following treatments: (1) a degraded riparian area with con...

  8. Geomorphic controls on riparian zone hydrology, carbon pools and fluxes of dissolved organic carbon

    NASA Astrophysics Data System (ADS)

    Grabs, T.; Ledesma, J.; Laudon, H.; Seibert, J.; Kohler, S. J.; Bishop, K. H.

    2014-12-01

    Near stream (riparian) zones are an important link between terrestrial and aquatic ecosystems and influence a wide range of processes including solute transport or hydrologic behavior of headwater catchments. Understanding the links between geomorphology and riparian soils, vegetation and hydrology is, thus, a prerequisite for relating small scale processes to observations at the watershed scale. Geographic information systems (GIS) have traditionally been used to study links between geomorphology and properties of terrestrial ecosystems. Applying this approach to riparian zones, however, has only recently become feasible with the availability of high-resolution digital elevation models and the new development of suitable computational methods. In this study we present links between geomorphology and riparian zone hydrology, carbon pools and fluxes of dissolved organic carbon. Geomorphometric attributes were successfully used to predict (1) riparian groundwater levels and flow pathways, (2) the size of riparian soil carbon pools, (3) the vertical variation of dissolved organic carbon (DOC) in riparian soil profiles, as well as (4) riparian carbon fluxes and turnover times.

  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. 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...

  11. Hot spots and hot moments in riparian zones: potential for improved water quality management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite considerable heterogeneity over space and time, biogeochemical and hydrological processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. Recently, these heterogeneous processes have been co...

  12. 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

  13. 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...

  14. Water sources accessed by arid zone riparian trees in highly saline environments, Australia.

    PubMed

    Costelloe, Justin F; Payne, Emily; Woodrow, Ian E; Irvine, Elizabeth C; Western, Andrew W; Leaney, Fred W

    2008-05-01

    The flow regimes of arid zone rivers are often highly variable, and shallow groundwater in the alluvial aquifers can be very saline, thus constraining the availability and quality of the major water sources available to riparian trees-soil water, shallow groundwater and stream water. We have identified water sources and strategies used by riparian trees in more highly saline and arid conditions than previously studied for riparian trees of arid zone rivers. Our research focused on the riparian species Eucalyptus coolabah, one of the major riparian trees of ephemeral arid zone rivers in Australia. The water sources available to this riparian tree were examined using delta(18)O isotope data from xylem, soil water, groundwater and surface water. Additionally, soil chloride and matric potential data were used to infer zones of water availability for root uptake. Despite the saline conditions, the trees used a mixture of soil water and groundwater sources, but they did not use surface water directly. The study identified three strategies used to cope with typically high groundwater and soil water salinities. Firstly, the trees preferentially grow in zones of most frequent flushing by infiltrating streamflow, such as the bank-tops of channels. Secondly, the trees limit water use by having low transpiration rates. Thirdly, the trees are able to extract water at very low osmotic potentials, with water uptake continuing at chloride concentrations of at least 20,000-30,000 mg L(-1). PMID:18270743

  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. Mitigation of Shallow Groundwater Nitrate in a Poorly Drained Riparian Area and Adjacent Cropland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian ecosystems, through their unique positions in the agricultural landscape and ability to influence nutrient cycles, have the potential to mitigate nutrient loading to surface and ground waters. The purpose of this study was to determine the fate of NO3 in shallow ground water moving along a...

  17. 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...

  18. 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

  19. 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.

  20. Spatiotemporal variation of nitrate in riparian zone seeps as a potential indicator of preferential flow pathways

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hydrology of the riparian zone plays an important role in regulating the water quality of agricultural watersheds. While slow flow pathways such as matrix flow offer opportunities for nutrient removal from water, faster flow pathways resulting from preferential flow often circumvent these treatm...

  1. 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...

  2. Microbial community structure across a wastewater-impacted riparian buffer zone in the southeastern Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffer zones are important for both natural and developed ecosystems throughout the world. However, their microbial community structure is only beginning to be defined and understood. Our objectives for this study were to characterize the microbial populations found in the soils of this rip...

  3. 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

  4. 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.

  5. 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

  6. 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.…

  7. Methane Flux in Cropland and Adjacent Riparian Buffers with Different Vegetation Covers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation buffers established adjacent to cropped fields are widely promoted as off-site sinks for nonpoint source sediment and nutrients. These perennial plant systems have the potential to serve as sinks of methane (CH4) or may provide favorable conditions for CH4 production. This study quantif...

  8. 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...

  9. Field-based evaluation tool for riparian buffer zones in agricultural catchments.

    PubMed

    Ducros, Caroline M J; Joyce, Chris B

    2003-08-01

    Riparian buffer zones can improve water quality and enhance habitat, but a comprehensive yet rapid method that can assist the resource manager in assessing the effectiveness of buffers is not available. The aim of this paper is to describe and illustrate the use of a newly developed field-based evaluation tool for riparian buffer zones in agricultural catchments. The Buffer Zone Inventory and Evaluation Form (BZIEF) incorporates criteria-based scoring systems developed from literature review, subsequent peer-review, and then a pilot field study. Use of the BZIEF is demonstrated by comparing buffer zones in three catchments established for water quality and habitat improvement under the Water Fringe Option agrienvironment scheme in England in order to assess whether the buffers were likely to provide environmental enhancement. Results among the three catchments were generally similar; buffer zones scored highly for their abundant vegetation cover, lack of erosion, stream habitat quality, and sufficient width. Furthermore, previous grassland or arable land use did not substantially affect buffer zone ratings. However, the BZIEF indicated that inappropriate soil characteristics in one catchment were likely to constrain buffer zone effectiveness for improving water quality. In another catchment, poor riparian vegetation diversity and structure may yield ineffective habitat enhancement, according to the BZIEF. It was concluded that the BZIEF might be a useful tool for buffer zone comparison and monitoring, even though more work is needed to test and validate the method. For example, the BZIEF could be used to target appropriate locations for buffer zones and is flexible, so could be adapted for different policies, objectives and regions. PMID:14753650

  10. 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 ...

  11. Groundwater Evapotranspiration in Arid Riparian Zone along the Downstream of the Yerqiang River

    NASA Astrophysics Data System (ADS)

    Cong, Zhentao; Dang, Qian; Pan, Baoxiang; Duan, Meng

    2013-04-01

    The Yerqiang river is a headstream of the Tarim river located in Northeast China. In some years, this river flows into the Tarim river in summer; and in other years, it can not reach to the mainstream. Therefore, the downstream of the Yerqiang river, where the precipitation is lower than 50mm, is hyper arid and the ecosystem is very fragile and depends on the groundwater. Groundwater evapotranspiration constitutes a major component of the water balance in arid riparian zone. Most of groundwater evapotranspiration studies depend on numerical models but it is not easy to discuss the controling factors of groundwater evapotranspiration in riparian zone. A site has been set up to observe weather, groundwater table and vegetation in this downstream. Then a two-dimension conceptal framework was applied to understand the groundwater evapotranspiration in this area.

  12. 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

  13. In situ push-pull method to determine ground water denitrification in riparian zones.

    PubMed

    Addy, Kelly; Kellogg, D Q; Gold, Arthur J; Groffman, Peter M; Ferendo, Gina; Sawyer, Carl

    2002-01-01

    To quantify ground water denitrification in discrete locations of riparian aquifers, we modified and evaluated an in situ method based on conservative tracers and 15N-enriched nitrate. Ground water was "pushed" (i.e., injected) into a mini-piezometer and then "pulled" (i.e., extracted) from the same mini-piezometer after an incubation period. This push-pull method was applied in replicate mini-piezometers at two Rhode Island riparian sites, one fresh water and one brackish water. Conservative tracer pretests were conducted to determine incubation periods, ranging from 5 to 120 h, to optimize recovery of introduced plumes. For nitrate push-pull tests, we used two conservative tracers, sulfur hexafluoride and bromide, to provide insight into plume recovery. The two conservative tracers behaved similarly. The dosing solutions were amended with 15N-enriched nitrate that enabled us to quantify the mass of denitrification gases generated during the incubation period. The in situ push-pull method detected substantial denitrification rates at a site where we had previously observed high denitrification rates. At our brackish site, we found high rates of ground water denitrification in marsh locations and minimal denitrification in soils fringing the marsh. The push-pull method can provide useful insights into spatial and temporal patterns of denitrification in riparian zones. The method is robust and results are not seriously affected by dilution or degassing from ground water to soil air. In conjunction with measurements of ground water flow-paths, this method holds promise for evaluating the influence of site and management factors on the ground water nitrate removal capacity of riparian zones. PMID:12026069

  14. Fate of Herbicides and Their Degradation Products Entering a Forested Riparian Buffer Following Herbicides Application to an Adjacent Corn Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of two herbicides, atrazine and metolachlor, were followed as they entered and moved through a forested riparian wetland located in the mid-Atlantic coastal plain of Maryland. The herbicides were applied as pre-emergent treatments to a 20-ha corn field directly upgradient of the riparian w...

  15. 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

  16. Cooling Along Hyporheic Pathlines in a Large River Riparian Zone

    NASA Astrophysics Data System (ADS)

    Faulkner, B. R.; Forshay, K. J.; Brooks, J.; Adeuya, R. K.; Cline, S. P.

    2012-12-01

    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. We used field data and numerical flow modeling in a region where cooling may influence the formation of coldwater refugia, a valuable ecosystem service for the preservation of salmon habitat. Hyporheic flow and ground water temperature were extensively monitored and characterized along a floodplain section of the Willamette River, Oregon, USA. Numerical flow modeling was done for the strongly contrasting dry and wet season flow patterns. During the warm dry season of our study, we observed significant temperature reduction with distance along most of the pathlines. Examination of particle tracking results indicate that in our site's floodplain areas, hyporheic flow during the wet season often has a locally downward component due to recharge from infiltration of rainfall, although dry season ground water flow also often moves deeper along the longer pathlines. In the dry season, pathlines trend to horizontal. Overall, the observed dry season temperature profiles obeyed the analytical solution to a one-dimensional steady-state governing equation for heat transfer in porous media, with differing thermal Péclet numbers. In one gravel bar, a mean pathline length of about 600 m reduced temperature 18 to 11 degrees Celsius. This cooling occurred over a residence time of 3-4 years before re-emergence, and incorporates the water table fluctuation, and wet season recharge from infiltration of rainfall that produces a locally downward trend of the hyporheic water prior to moving upward and discharging to cutoffs and alcoves. In some of the islands, wet season ground water underwent sufficient mounding to halt or reverse dry season river water that had entered the hyporheic zone. In our floodplain site water

  17. Groundwater phosphate dynamics in a river riparian zone: effects of hydrologic flowpaths, lithology and redox chemistry

    NASA Astrophysics Data System (ADS)

    Carlyle, G. C.; Hill, A. R.

    2001-07-01

    This study examines the influence of riparian zone hydrology, lithology and redox chemistry on groundwater phosphate dynamics. Patterns of soluble reactive phosphorus (SRP), dissolved oxygen (DO) and ferrous iron (Fe 2+) in combination with hydrologic data and sediment characteristics were studied in a forested floodplain connected to a large upland sand aquifer in an agricultural region of southern Ontario, Canada. Groundwater discharge from the upland aquifer flowed laterally beneath peat in a 2-4 m thick zone of permeable sands across the floodplain to the river. Within the sands, low SRP concentrations (<25 μg L -1) occurred in a plume of groundwater with DO concentrations >3 mg L -1 and Fe 2+ concentrations <0.2 mg L -1 which extended for a horizontal distance of 100-140 m across the riparian zone. High SRP concentrations (50-950 μg L -1) were associated with low DO and high Fe 2+ concentrations which exceeded 1 mg L -1 in buried channel sediments near the river bank. Sediment P fractionation indicated that the buried channel sediments contained a much higher pool of total P and Fe+Al-P than the sands. Groundwater SRP concentrations at the river bank were 25-80 μg L -1 compared to <10 μg L -1 in river water indicating that the floodplain was a source of SRP to the river. Areas of elevated SRP and Fe 2+ within the floodplain expanded in August when DO concentrations in groundwater were lower than in late spring or autumn. These data suggest that the microbial reduction of Fe 3+ to soluble Fe 2+ in anaerobic conditions influences groundwater SRP concentrations in the riparian zone. This study shows that well-organized patterns of groundwater SRP concentrations occur in riparian zones which reflect the interaction of hydrologic flowpaths and environments of different redox state. Internal sources of P associated with buried channel sediments can also influence subsurface SRP transport and release to streams.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. 334.70 Section 334.70 Navigation and Navigable Waters CORPS... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a)...

  19. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. 334.70 Section 334.70 Navigation and Navigable Waters CORPS... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a)...

  20. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. 334.70 Section 334.70 Navigation and Navigable Waters CORPS... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a)...

  1. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. 334.70 Section 334.70 Navigation and Navigable Waters CORPS... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a)...

  2. 33 CFR 334.70 - Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. 334.70 Section 334.70 Navigation and Navigable Waters CORPS... REGULATIONS § 334.70 Buzzards Bay, and adjacent waters, Mass.; danger zones for naval operations. (a)...

  3. A Comprehensive Monitoring Plan for the Fourmile Branch Riparian Zone at the Savannah River Site

    NASA Astrophysics Data System (ADS)

    Dunn, D. L.

    2002-05-01

    Since the late 1960's, numerous environmental investigations have been conducted along the Fourmile Branch riparian zone, which is down-gradient from the General Separations Area (GSA). The GSA is a complex of nuclear defense facilities consisting of F & H Areas, the Burial Grounds, and the Mixed Waste Management Facility (MWMF) at the Savannah River Site (SRS) in Aiken, South Carolina. Because of differences in objectives and sampling designs, some of the resulting historical information has been fragmented, duplicative, and inadequate to comprehensively understand contaminant plume migration, risk to human health and the environment, and effectiveness of remedial action. A new monitoring plan defines a strategy to critically evaluate past and existing sampling approaches and to develop a holistic approach that is comprehensive, cost-effective, and commensurate with the remediation goals set forth in existing permits and agreements with the regulatory agencies. Specifically, the objectives of the monitoring plan are to: (1) review historical sampling programs and identify baseline and operational data bases, (2) consolidate and characterize historic sampling locations, (3) based on the most recent modeling and plume delineations, identify sampling locations that will comprehensively characterize groundwater and surface water plume migrations. The riparian zone of interest will include the wetlands and seeplines down-gradient from the GSA. The media of concern will include the surface waters associated with the seeplines and Fourmile Branch plus the groundwaters of the upper and lower aquifers. Sampling will be conducted using automated surface water samplers and depth-discrete multilevel monitoring wells.

  4. 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.

  5. Using Aerial Photography to Estimate Riparian Zone Impacts in a Rapidly Developing River Corridor

    NASA Astrophysics Data System (ADS)

    Owers, Katharine A.; Albanese, Brett; Litts, Thomas

    2012-03-01

    Riparian zones are critical for protecting water quality and wildlife, but are often impacted by human activities. Ongoing threats and uncertainty about the effectiveness of buffer regulations emphasize the importance of monitoring riparian buffers through time. We developed a method to rapidly categorize buffer width and landuse attributes using 2007 leaf-on aerial photography and applied it to a 65 km section of the Toccoa River in north Georgia. We repeated our protocol using 1999 leaf-off aerial photographs to assess the utility of our approach for monitoring. Almost half (45%) of the length of the Toccoa River was bordered by buffers less than 50 ft wide in 2007, with agricultural and built-up lands having the smallest buffers. The percentage of river length in each buffer width category changed little between 1999 and 2007, but we did detect a 5% decrease in agricultural land use, a corresponding increase in built-up land use, and an additional 149 buildings within 100 ft of the river. Field verification indicated that our method overestimated buffer widths and forested land use and underestimated built-up land use and the number of buildings within 100 ft of the river. Our methodology can be used to rapidly assess the status of riparian buffers. Including supplemental data (e.g., leaf-off imagery, road layers) will allow detection of the fine-scale impacts underestimated in our study. Our results on the Toccoa River reflect historic impacts, exemptions and variances to regulations, and the ongoing threat of vacation home development. We recommend additional monitoring, improvements in policy, and efforts to increase voluntary protection and restoration of stream buffers.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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...

  12. DEVELOPMENT OF MOLECULAR BIOMARKERS AS INDICATORS OF STRESSOR AND ECOLOGICAL CONDITIONS AT THE SUBSURFACE OF RIPARIAN BUFFER ZONES

    EPA Science Inventory

    The primary objective of this study is to develop biomarkers for practical use in the evaluation of nitrogen dynamics of riparian buffer zones. Molecular biology-based methodology will be employed to obtain information about the total microbial community present as well as to th...

  13. Reduced riparian zone width compromises aquatic macroinvertebrate communities in streams of southern Brazil.

    PubMed

    Moraes, Aline Bianca; Wilhelm, Andréia Emília; Boelter, Thaíse; Stenert, Cristina; Schulz, Uwe H; Maltchik, Leonardo

    2014-11-01

    Recent changes in Brazilian legislation reduced the width of riparian forest buffer needed to be preserved in private properties from 30 to 15 m or less. The consequences of these modifications can be dramatic, mainly because riparian buffer width is an important parameter for riparian forest structure and functioning. Our study assessed whether (1) macroinvertebrate family richness and Ephemeroptera, Plecoptera, and Trichoptera (EPT) family richness decrease with reduced riparian buffer width; (2) taxonomic composition and functional feeding group (FFG) composition of macroinvertebrates vary with a reduced riparian buffer width; and (3) reduced riparian buffer width similarly influence the macroinvertebrate community in different stream substrates. We selected three fragments with different riparian buffer widths (>40, <30, and <15 m) in three streams (fourth and fifth orders) in the Sinos River watershed, southern Brazil. Our results show that on all substrate types, reducing the width of the riparian buffer altered neither the macroinvertebrate richness nor EPT richness. However, EPT richness was greater in the substrates stone and gravel than leaf litter, independent of riparian buffer width. There was a significant difference in macroinvertebrate composition among riparian buffer widths. The macroinvertebrate composition and FFG differed among substrates, independent of riparian buffer width. This study showed that riparian buffer widths <15 m altered the macroinvertebrate community. A width greater than 15 m is necessary to maintain the composition and trophic conditions of macroinvertebrate families similar to those found in reference states of conservation. PMID:25052327

  14. 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

  15. 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. PMID:26169979

  16. 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

  17. The chemical composition and source identification of soil dissolved organic matter in riparian buffer zones from Chongming Island, China.

    PubMed

    Wang, Yulai; Yang, Changming; Li, Jianhua; Shen, Shuo

    2014-09-01

    Dissolved organic matter (DOM) that is derived from the soil of riparian buffer zones has a complex chemical composition, and it plays an important role in the transport and transformation of pollutants. To identify the source of DOM and to better understand its chemical and structural properties, we collected 33 soil samples from zones with fluctuating water levels along the major rivers on Chongming Island, evaluated the DOM contents in riparian soil, analyzed the chemical composition and functional groups and traced DOM origins by using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) combined with clustering analysis. All sampling sites were divided into four groups by principal component analysis (PCA) on the basis of the DOM molecules. The results showed that there was no significant difference in the DOM contents between every two groups; however, the DOM fractions differed significantly among the different site groups in the following order: Σ lipids and Σ proteins>Σ sugars and Σ fatty acids>Σ amino acids, Σ indoles and Σ alkaloids. DOM in the riparian buffer zones originated from riparian plants, domestic sewage and agricultural activities, and the hydrophobic and amphiphilic fractions accounting for over 60% of the identified molecules were the dominant fractions. Our study has confirmed the heterogeneous properties of DOM, and it is of vital importance to isolate and characterize the various DOM fractions at the molecular level for a better understanding of the behavior and roles of DOM in the natural environment. PMID:24997959

  18. 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

  19. Quantifying riparian zone structure from airborne LiDAR: Vegetation filtering, anisotropic interpolation, and uncertainty propagation

    NASA Astrophysics Data System (ADS)

    Hutton, Christopher; Brazier, Richard

    2012-06-01

    SummaryAdvances in remote sensing technology, notably in airborne Light Detection And Ranging (LiDAR), have facilitated the acquisition of high-resolution topographic and vegetation datasets over increasingly large areas. Whilst such datasets may provide quantitative information on surface morphology and vegetation structure in riparian zones, existing approaches for processing raw LiDAR data perform poorly in riparian channel environments. A new algorithm for separating vegetation from topography in raw LiDAR data, and the performance of the Elliptical Inverse Distance Weighting (EIDW) procedure for interpolating the remaining ground points, are evaluated using data derived from a semi-arid ephemeral river. The filtering procedure, which first applies a threshold (either slope or elevation) to classify vegetation high-points, and second a regional growing algorithm from these high-points, avoids the classification of high channel banks as vegetation, preserving existing channel morphology for subsequent interpolation (2.90-9.21% calibration error; 4.53-7.44% error in evaluation for slope threshold). EIDW, which accounts for surface anisotropy by converting the remaining elevation points to streamwise co-ordinates, can outperform isoptropic interpolation (IDW) on channel banks, however, performs less well in isotropic conditions, and when local anisotropy is different to that of the main channel. A key finding of this research is that filtering parameter uncertainty affects the performance of the interpolation procedure; resultant errors may propagate into the Digital Elevation Model (DEM) and subsequently derived products, such as Canopy Height Models (CHMs). Consequently, it is important that this uncertainty is assessed. Understanding and developing methods to deal with such errors is important to inform users of the true quality of laser scanning products, such that they can be used effectively in hydrological applications.

  20. 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... existing 1.8 mile Danger Zone [as described in Sec. 334.420(b)(1)(i)] in the Pamlico Sound and...

  1. 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

  2. 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

  3. 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

  4. Dynamic evaluation of ecosystem service value of the riparian zone based on remote sensing from 1986 to 2012

    NASA Astrophysics Data System (ADS)

    Fu, B. L.; Li, Y.; Zhang, B.; Yin, B. S.; Zhu, H. L.; Xing, Z. F.

    2015-08-01

    In this paper, we calculated comparable and dynamic ecosystem service value per unit area in the riparian zone of Second Songhua River; then we also estimated changes in the value of ecosystem services resulting from land use changes; finally, we continuously evaluated the riparian ecosystem service value based on 520 basic evaluation units (BEUs) and explored the trend of the riparian ecosystem service value from 1986 to 2012. The results indicated that comparable economic values of per unit area food production of farmland ecosystems in 2012 almost increased three times more than that in 1986 from 154.83 to 382.45 ha-1; the people's willingness to pay for farmland ecosystem services increased from 0.24 in 1986 to 0.48 in 2012; the land areas supporting the environment and society generally declined, whereas areas of farmland significantly increased from 1986 to 2012; the riparian total ecosystem service value increased from 42.30 million in 1986 to 119.67 million in 2012, with an average increase rate of 4.06 % yr-1; the ecosystem service value of four reaches all have seen a sharp increase from 1986 to 2012; the average ecosystem service value of a reach was the smallest one in the four reaches, and the value of c and d reach was significantly more than other two reaches.

  5. Water and Vapor Transfer in Vadose Zone of Gobi Desert and Riparian in the Hyper Arid Environment of Ejina, China

    NASA Astrophysics Data System (ADS)

    Du, C.; Yu, J.; Wang, P.

    2014-12-01

    To reveal how water and vapor transfer in vadose zone affect evapotranspiration in Gobi desert and riparian in hyper arid region is important for understanding eco-hydrological process. Field studies and numerical simulations were imported to evaluate the water and vapor movement processes under non isothermal and lower water content conditions. The soil profiles (12 layers) in Gobi desert and riparian sites of Ejina were installed with sensors to monitor soil moisture and temperature for 1 year. The meteorological conditions and water table were measured by micro weather stations and mini-Divers respectively in the two sites. Soil properties, including particles composition, moisture, bulk density, water retention curve, and saturated hydraulic conductivity of two site soil profiles, was measured. The observations showed that soil temperatures for the two sites displayed large diurnal and seasonal fluctuations. Temperature gradients with depth resulted in a downward in summer and upward in winter and became driving force for thermal vapor movement. Soil moistures in Gobi desert site were very low and varied slowly with time. While the soil moistures in riparian site were complicated due to root distribution but water potentials remained uniform with time. The hydrus-1D was employed to simulate evapotranspiration processes. The simulation results showed the significant difference of evaporation rate in the Gobi desert and riparian sites.

  6. 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

  7. Anammox bacteria community and nitrogen removal in a strip-like wetland in the riparian zone.

    PubMed

    Pei, Yuansheng; Wang, Jun; Wang, Ziyuan; Tian, Binghui

    2011-01-01

    A strip-like wetland was constructed in the riparian zone for investigation of ammonium nitrogen (NH(3)-N) removal in the Peach River. An inner zeolite layer was set in the wetland to adsorb NH(3)-N and further to remove total nitrogen (TN). An oxygen-deficient condition with dissolved oxygen of 0.87-1.60 mg L(-1) was observed in the zeolite layer, which benefits anaerobic ammonium oxidation (anammox) bacteria survival. The community structure of anammox bacteria was analyzed in the zeolite layer. The analysis shows that the anammox bacterial sequences are grouped into three known distinct clusters: Candidatus Brocadia fulgida, Candidatus Brocadia anammoxidans and Candidatus Jettenia asiatica. The intensified test driven by artificial pumping shows that average removal rates of NH(3)-N and TN are 41.6 mg m(-3)d(-1) and 63.2 mg m(-3)d(-1), respectively. The normal test driven by natural hydrodynamics also verifies that NH(3)-N removal mainly happens in the zeolite layer. Microbial mechanism of TN removal in the wetland involves both the autotrophic and heterotrophic process. These results suggest that the strip-like RW can be a cost-effective approach for NH(3)-N removal and can potentially be extended to similar rivers as no extra energy is required to maintain the wetland operation. PMID:21644147

  8. Impacts of Riparian Zone Plant Water Use on Fractal Dynamics of Groundwater Levels

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Young, M.

    2011-12-01

    In areas where plants directly tap groundwater for their water supply, hydrographs from the water table typically display diurnal fluctuations superimposed on other larger and smaller trends during the plant growing season. In this work, we investigate groundwater system dynamics in relation to plant water use and near-river stage fluctuations in riparian zones where phreatophytes exist. Using detrended fluctuation analysis (DFA), we examine the influence of regular diurnal fluctuations due to phreatophyte water use on long temporal scaling properties of groundwater level variations. We found that groundwater use by phreatophytes, at the field site on the Colorado River, USA, results in distinctive slope changes in the logarithm plots of root-mean-square fluctuations of the detrended time series vs. time scales of groundwater level dynamics. For groundwater levels monitored at wells close to the river, we identified one slope change at ~1 day in the fractal scaling characteristics of groundwater level variations. When time scale exceeds 1 day, the scaling properties decrease from persistent to 1/f noise, where f is the frequency. For groundwater levels recorded at wells further from the river, the slope of the straight line fit (i.e., scaling exponent) is smallest when the time scale is between 1 to ~3 days. When the time scale is <1 day, groundwater variations become persistent. When the time scale is between 1 - 3 days, the variations are close to white noise, but return to persistent when the time scale is >~3 days.

  9. 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.

  10. 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. PMID:25611952

  11. 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

  12. Quantifying nitrate retention processes in a riparian buffer zone using the natural abundance of 15N in NO3-.

    PubMed

    Dhondt, Karel; Boeckx, Pascal; Van Cleemput, Oswald; Hofman, Georges

    2003-01-01

    Quantifying the relative importance of denitrification and plant uptake to groundwater nitrate retention in riparian zones may lead to methods optimising the construction of riparian zones for water pollution control. The natural abundance of 15N in NO3- has been shown to be an interesting tool for providing insights into the NO3- retention processes occurring in riparian zones. In this study, 15N isotope fractionation (variation in delta15N of the residual NO3-) due to denitrification and due to plant uptake was measured in anaerobic soil slurries at different temperatures (5, 10 and 15 degrees C) and in hydroponic systems with different plant species (Lolium perenne L., Urtica dioica L. and Epilobium hirsutum L.). It was found that temperature had no significant effect on isotope fractionation during denitrification, which resulted in a 15N enrichment factor epsilonD of -22.5 +/- 0.6 per thousand. On the other hand, nitrate uptake by plants resulted in 15N isotope fractionation, but was independent of plant species, leading to a 15N enrichment factor epsilonP of -4.4 +/- 0.3 per thousand. By relating these two laboratory-defined enrichment factors to a field enrichment factor for groundwater nitrate retention during the growing season (epsilonR = -15.5 +/- 1.0 per thousand ), the contribution of denitrification and plant uptake to groundwater nitrate retention could be calculated. The relative importance of denitrification and plant uptake to groundwater nitrate retention in the riparian buffer zone was 49 and 51% during spring, 53 and 47% during summer, and 75 and 25% during autumn. During wintertime, high micropore dissolved organic carbon (DOC) concentrations and low redox potentials due to decomposition of the highly productive riparian vegetation probably resulted in a higher denitrification rate and favoured other nitrate retention processes such as nitrate immobilisation or dissimilatory nitrate reduction to ammonium (DNRA). This could have biased the 15N

  13. 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

  14. 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.

  15. 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.

  16. 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. PMID:22963127

  17. [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. PMID:25898664

  18. 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

  19. 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

  20. 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 ...

  1. Denitrification gene density across a wastewater-impacted riparian buffer zone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are a best management practice used extensively to protect water bodies from agriculturally-generated nitrate pollution. In particular, the biological process of denitrification has been shown to be a sink for this nitrate. Denitrification results in the reduction of nitrate under a...

  2. 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...

  3. Hydrological controls on denitrification in riparian zone of forested headwater catchment: Soil physical properties make difference in reduced environment

    NASA Astrophysics Data System (ADS)

    Ohte, N.; Watanabe, Y.; Oda, T.; Osaka, K.

    2010-12-01

    Riparian zone near stream plays important roles to control the solute discharge from hillslope to stream. Supply of inorganic nitrogen as an essential nutrient of aquatic primary producers is generally regulated by hydrological and biogeochemical processes such as denitrification in this unique landscape unit in headwaters. To elucidate how the denitrification is controlled by hydrological properties of riparian groundwater aquifer, we investigated two similar scaled forested headwater catchments with different soil physical properties in Japan. The Kiryu- Matsuzawa catchment (KEW, 0.6 ha) has weathered granitic bedrock, and its soils in riparian zones are sandy, while the Fukuroyama-sawa catchment (FEW, 1.1 ha) has Tertiary sedimentary bedrock, and has clayey soils. Concentrations, δ15N and δ18O of NO3- in soil water, groundwater and streamwater were monitored during 2007 - 2009. Enrichment in δ15N-NO3- was found in the perennial groundwater bodies both in KEW and FEW, indicating active denitrification occurred (Fig 1). In the same time, however, increase in δ18O-NO3- of KEW groundwater was unclear, while that of FEW was found clearly indicating the denitrification under a closed system without significant dissolved O2 (DO) and new NO3- supply. It was also suggested that the denitrification in the KEW groundwater occurred under condition with relatively high DO, and new NO3- recharge by lateral groundwater movement. These differences were explainable by hydrological features of soils holding groundwater: The mean residence time (MRT) of the groundwater in FEW was estimated as three times longer (>1000 days) than that in KEW (<300 days). Moreover, this difference in MRT of groundwater aquifer is essentially caused by difference in the soil water retention characteristics between sandy soil in KEW and clayey soil in FEW. Those indicated the possibility that the difference of soil physical properties can be reflected strongly on inorganic nitrogen discharge from

  4. 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.

  5. 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

  6. 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

  7. [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

  8. 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

  9. 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.

  10. 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

  11. 33 CFR 334.420 - Pamlico Sound and adjacent waters, N.C.; danger zones for Marine Corps operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Pamlico Sound and adjacent waters... REGULATIONS § 334.420 Pamlico Sound and adjacent waters, N.C.; danger zones for Marine Corps operations. (a) Bombing and rocket firing area in Pamlico Sound in vicinity of Brant Island—(1) The area. The...

  12. 33 CFR 334.420 - Pamlico Sound and adjacent waters, N.C.; danger zones for Marine Corps operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pamlico Sound and adjacent waters... REGULATIONS § 334.420 Pamlico Sound and adjacent waters, N.C.; danger zones for Marine Corps operations. (a) Bombing and rocket firing area in Pamlico Sound in vicinity of Brant Island—(1) The area. The...

  13. Riparian Vegetation Mapping Along the Hanford Reach

    SciTech Connect

    FOGWELL, T.W.

    2003-07-11

    During the biological survey and inventory of the Hanford Site conducted in the mid-1990s (1995 and 1996), preliminary surveys of the riparian vegetation were conducted along the Hanford Reach. These preliminary data were reported to The Nature Conservancy (TNC), but were not included in any TNC reports to DOE or stakeholders. During the latter part of FY2001, PNNL contracted with SEE Botanical, the parties that performed the original surveys in the mid 1990s, to complete the data summaries and mapping associated with the earlier survey data. Those data sets were delivered to PNNL and the riparian mapping by vegetation type for the Hanford Reach is being digitized during the first quarter of FY2002. These mapping efforts provide the information necessary to create subsequent spatial data layers to describe the riparian zone according to plant functional types (trees, shrubs, grasses, sedges, forbs). Quantification of the riparian zone by vegetation types is important to a number of DOE'S priority issues including modeling contaminant transport and uptake in the near-riverine environment and the determination of ecological risk. This work included the identification of vegetative zones along the Reach by changes in dominant plant species covering the shoreline from just to the north of the 300 Area to China Bar near Vernita. Dominant and indicator species included Agropyron dasytachyudA. smithii, Apocynum cannabinum, Aristida longiseta, Artemisia campestris ssp. borealis var scouleriana, Artemisa dracunculus, Artemisia lindleyana, Artemisia tridentata, Bromus tectorum, Chrysothamnus nauseosus, Coreopsis atkinsoniana. Eleocharis palustris, Elymus cinereus, Equisetum hyemale, Eriogonum compositum, Juniperus trichocarpa, Phalaris arundinacea, Poa compressa. Salk exigua, Scirpus acutus, Solidago occidentalis, Sporobolus asper,and Sporobolus cryptandrus. This letter report documents the data received, the processing by PNNL staff, and additional data gathered in FY2002

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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.

  1. Seismic imaging of mantle transition zone discontinuities beneath the northern Red Sea and adjacent areas

    NASA Astrophysics Data System (ADS)

    Mohamed, A. A.; Gao, S. S.; Elsheikh, A. A.; Liu, K. H.; Yu, Y.; Fat-Helbary, R. E.

    2014-11-01

    The dramatic asymmetry in terms of surface elevation, Cenozoic volcanisms and earthquake activity across the Red Sea is an enigmatic issue in global tectonics, partially due to the unavailability of broad-band seismic data on the African Plate adjacent to the Red Sea. Here, we report the first comprehensive image of the mantle transition zone (MTZ) discontinuities using data from the Egyptian National Seismic Network, and compare the resulting depths of the 410 and 660-km discontinuities with those observed on the Arabian side. Our results show that when a standard earth model is used for time-to-depth conversion, the resulting depth of the discontinuities increases systematically towards the axis of the Afro-Arabian Dome (AAD) from both the west and east. Relative to the westernmost area, the maximum depression of the 410-km discontinuity is about 30 km, and that of the 660-km discontinuity is about 45 km. The observed systematic variations can best be explained by a model involving a hydrated MTZ and an upper-mantle low-velocity zone beneath the AAD. Models invoking one or more mantle plumes originated from the MTZ or the lower-mantle beneath the study area are not consistent with the observations.

  2. 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

  3. Dynamic simulation of vegetation abundance in a reservoir riparian zone using a sub-pixel Markov model

    NASA Astrophysics Data System (ADS)

    Gong, Zhaoning; Cui, Tianxiang; Pu, Ruiliang; Lin, Chuan; Chen, Yuzhu

    2015-03-01

    Vegetation abundance is a significant indicator for measuring the coverage of plant community. It is also a fundamental data for the evaluation of a reservoir riparian zone eco-environment. In this study, a sub-pixel Markov model was introduced and applied to simulate dynamics of vegetation abundance in the Guanting Reservoir Riparian zone based on seven Landsat Thematic Mapper/Enhanced Thematic Mapper Plus/Operational Land Imager data acquired between 2001 and 2013. Our study extended Markov model's application from a traditional regional scale to a sub-pixel scale. Firstly, Linear Spectral Mixture Analysis (LSMA) was used to obtain fractional images with a five-endmember model consisting of terrestrial plants, aquatic plants, high albedo, low albedo, and bare soil. Then, a sub-pixel transitive probability matrix was calculated. Based on the matrix, we simulated statuses of vegetation abundance in 2010 and 2013, which were compared with the results created by LSMA. Validations showed that there were only slight differences between the LSMA derived results and the simulated terrestrial plants fractional images for both 2010 and 2013, while obvious differences existed for aquatic plants fractional images, which might be attributed to a dramatically diversity of water level and water discharge between 2001 and 2013. Moreover, the sub-pixel Markov model could lead to an RMSE (Root Mean Square Error) of 0.105 and an R2 of 0.808 for terrestrial plants, and an RMSE of 0.044 and an R2 of 0.784 for aquatic plants in 2010. For the simulated results with the 2013 image, an RMSE of 0.126 and an R2 of 0.768 could be achieved for terrestrial plants, and an RMSE of 0.086 and an R2 of 0.779 could be yielded for aquatic plants. These results suggested that the sub-pixel Markov model could yield a reasonable result in a short period. Additionally, an analysis of dynamics of vegetation abundance from 2001 to 2020 indicated that there existed an increasing trend for the average

  4. Soil Moisture Monitoring Network Using Multi-Sensor Capacitance Probes in a Thick Vadose Zone Under Riparian Vegetation

    NASA Astrophysics Data System (ADS)

    Solis, J. A.; Rajaram, H.

    2011-12-01

    Soil moisture profile measurements are an integral component of water balance estimation networks, especially in thick vadose zones and fine-grained soil environments. At field sites with silty and stiff clayey soils, installation of sensors at multiple depths poses a challenge. One approach that has gained popularity is a multi-sensor capacitance (EniroSCAN) probe system manufactured by Sentek technologies. This requires only a single borehole where a 56.5 mm PVC access tube is installed. A very attractive feature of this system is that the sensors can be positioned at different depths without having to disturb the soil since the sensors are located on a cartridge unit that rides within the access tube and can be moved in 10 cm increments. We report the design and installation of a distributed soil moisture sensor network in a riparian zone within the Whitewater Basin in Central Kansas. The soil-moisture monitoring network used in this study is compromised of 6 profilers (each covering a depth of 2 m) with 4-5 sensors per profile, located at different depths. The network is connected to a centralized data logger, from which it can be accessed remotely through a telemetry system in real-time. The network obtains distributed soil moisture measurements every 15 minutes. All profilers exhibit a rapid response to precipitation events at depths < 1m. During the leaf-out stage, sensors at depths < 1.5 m exhibit diurnal fluctuations in response to plant water uptake. The temporal trends and response to rainfall/plant uptake is significantly different at the different profile locations, illustrating the significant heterogeneity at the site. The moisture profiles clearly demonstrate the gradual replenishment of soil moisture both by precipitation and capillary rise during fall and winter, followed by depletion (with diurnal variations superimposed) during the leaf-out stage of riparian vegetation. We describe the calibration efforts needed to convert the dielectric

  5. Compositional Comparison of Iceland Rift Zones and Adjacent Portions of the Mid-Atlantic Ridge.

    NASA Astrophysics Data System (ADS)

    Kelley, D.; Barton, M.

    2007-12-01

    Iceland is a portion of the Mid-Atlantic Ridge (MAR) that has been built by anomalous crustal production throughout the 55ma spreading history of the opening of the Atlantic Ocean. The anomalously thick crust of Iceland contains the subaerial traces of the MAR which are the volcanically active rift zones. From the south, the Reykjanes Ridge (RR) continues on land as the Western Volcanic Zone (WVZ). In the north, the Northern Volcanic Zone (NVZ) traces into the sea where it offset from the Kolbeinsey Ridge (KR) by the Tjornnes Fracture Zone (TVZ). We report the results of petrologic comparison of the WVZ, the EVZ, and the NVZ of Iceland and the adjacent portions of the MAR - the RR and the KR. The EVZ, WVZ, and NVZ have been shown to have similar crustal structures with ~20 km thick crust thickening toward the hotspot in central Iceland with magma chambers located at the base of the crust and at some depth in the upper crust. Likewise, the KR and RR have melt chambers at the base of and within the crust. Melt compositions have been compared using a filtered database of 588 glass analyses from 29 localities throughout the rift zones, 57 glass analyses from the KR, and 521 glass analyses from the RR. This is the first such study carried out with such an extensive data set. Compositions are similar between the NVZ and WVZ with SiO2 wt.% of 49.0, and 48.6, MgO wt.% of 7.9, and 7.5, and FeOT wt.% of 10.9, and 11.7 respectively. The EVZ which is considered to be a propagating rift is a bit different with SiO2 wt.% of 49.4, MgO wt.% of 5.9, and FeOT wt.% of 13.8. The NVZ and WVZ have also been compared with their respectively adjacent ridge segments, the KR (SiO2 50.3 wt.%, MgO 6.9 wt.%, and FeOT 12.0 wt.%), and the RR (SiO2 50.8 wt.%, MgO 6.9 wt.%, and FeOT 12.3 wt.%). Mg#s for the NVZ and the WVZ are 0.56, and .053 respectively while the Mg# for both the KR and RR is 0.50. For further comparison, a database of 9035 glass analyses from mid-ocean ridge basalts worldwide

  6. 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

  7. 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. PMID:23811358

  8. 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.

  9. 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...

  10. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 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...

  11. 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

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 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...

  12. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 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...

  13. [Floristic composition and distribution of the Andean subtropical riparian forests of Lules River, Tucuman, Argentina].

    PubMed

    Sirombra, Martín G; Mesa, Leticia M

    2010-03-01

    We studied the floristic composition and distribution of the riparian forest of two hydrographical systems in a subtropical Andean region. Using uni and multivariate techniques, we tested the hypotheses that a differentiable riparian forest exists, composed by native vegetation typical of the Yungas phytogeographical province, and that the distribution of vegetation varied significantly with geomorphologic characteristics. Parallel transects along the water courses were used to collect presence-absence data of vegetation in eleven sites. Detrended Correspondence Analysis defined a group of common riparian species for the studied area (Solanum riparium, Phenax laevigatus, Tipuana tipu, Cestrum parqui, Carica quercifolia, Acacia macracantha, Celtis iguanaea, Juglans australis, Pisoniella arborescens, Baccharis salicifolia, Cinnamomum porphyrium and Eugenia uniflora) and identified two reference sites. The distribution of the riparian vegetation varied significantly with the geomorphic characteristics along the studied sites. Riparian habitats were composed by native and exotic species. A distinct riparian flora, different in structure and function from adjacent terrestrial vegetation, could not be identified. Riparian species were similar to the adjacent terrestrial strata. These species would not be limited by the proximity to the river. Anthropogenic impacts were important factors regulating the introduction and increase of exotic vegetation. The lack of regulation of some activities in the zone could cause serious problems in the integrity of this ecosystem. PMID:20411737

  14. 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.

  15. Nitrogen dynamics in the shallow groundwater of a riparian wetland zone of the Garonne, SW France: nitrate inputs, bacterial densities, organic matter supply and denitrification measurements

    NASA Astrophysics Data System (ADS)

    Sánchez-Pérez, J. M.; Vervier, P.; Garabétian, F.; Sauvage, S.; Loubet, M.; Rols, J. L.; Bariac, T.; Weng, P.

    This study highlights the role of interactions between surface and sub-surface water of the riparian zone of a large river (the Garonne, SW France). Information is given about the role of surface water in supplying Dissolved Organic Carbon (DOC ) to the riparian zone for nitrate removal processes. The densities of bacteria (up to 3.3 106 cell m L-1) in groundwater are strongly conditioned by the water moving during flood events. Total bacterial densities in groundwater were related to surface water bacterial densities. In sediment, total bacteria are attached mainly to fine particles (90% in the fraction < 1 mm). Spatial variations in organic carbon and nitrate content in groundwater at the site studied are correlated with exchanges between the groundwater and the river, from the upstream to the downstream part of the meander. Total bacterial densities, nitrate and decressing organic carbon concentrations follow the same pattern. These results suggest that, in this kind of riparian wetland, nitrate from alluvial groundwater influenced by agricultural practices may be denitrified by bacteria in the presence of organic carbon from river surface water.

  16. 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

  17. 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.

  18. 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. PMID:22751075

  19. 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

  20. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle use of riparian areas may lead to stream water contamination with nutrients, pathogens, and sediments. Thus, 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 th...

  2. Structural character of Hosgri fault zone and adjacent areas in offshore central California

    SciTech Connect

    Crouch, J.K.; Bachman, S.B.

    1987-05-01

    The Hosgri fault zone extends from the east-west Transverse Ranges structures near Point Arguello northward for more than 150 km to the offshore area near San Simeon Point. The fault zone is seismically active and consists chiefly of a continuous series of eastside-up thrust and high-angle reverse faults. East of the fault zone, Miocene Monterey and volcanic rocks, along with underlying pre-Miocene strata, have been tightly folded as a result of low-angle imbricate thrust faulting during post-Miocene time. These highly deformed strata have been uplited and truncated along the inner shelf. Immediately west of the Hosgria fault zone, similar Monterey and older rocks, which are less folded, conformably underlie Pliocene and younger basinal strata at structural levels that are generally 1200 to 2000 m deeper than correlative strata east of the Hosgri fault zone. Following its discovery in 1971, the Hosgri fault zone was characterized by subsequent investigators as a northwest-trending fault that was part of the San Andreas system of strike-slip faults, with disagreements on the timing and amount of right-lateral offset along the fault zone. However, modern offshore seismic-reflection data, earthquake focal-mechanism studies, and recently available offshore well information suggest that the Hosgri fault zone is instead a major imbricate thrust zone. Detailed structural analyses along part of the Hosgri fault zone suggest that little, if any, strike-slip offset has occurred along this structural trend since its post-Miocene inception. Nevertheless, the Hosgri fault zone itself can be interpreted to be a product of the larger overall San Andreas transform system in that compression has developed because the San Andreas is not parallel to the Pacific-North American plate motion.

  3. 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. PMID:16922216

  4. 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

  5. Changes in concentrations of a TCE plume in near- stream zones of a DNAPL contaminated area adjacent to a stream

    NASA Astrophysics Data System (ADS)

    Lee, S.; Hyun, Y.; Lee, K.

    2012-12-01

    A field investigation of a trichloroethylene (TCE) groundwater plume originating at an industrial complex and its discharges to a stream nearby showed that apparent plume attenuation occurred in the near-stream zone of a DNAPL contaminated area adjacent to a stream prior to discharging to the stream. The concentrations of TCE and cis-1,2-dichloroethene (cis-DCE) in groundwater, hyporheic water, stream water and streambed, and hydrogeology were characterized using mini-piezometers, monitoring wells, Ground Penetrating Radar (GPR) surveys, and soil coring. In the near stream zones temporal and spatial TCE plume concentration changes and mass fluxes were investigated along the flowpath of groundwater discharging to the stream. It is evident that observed concentrations of contaminants (TCE and cis-DCE) were reduced in the near-stream zone, resulting that TCE and cis-DCE were not detected in the streambed and stream water. Ground GPR surveys done in the near stream zone found that wire and water treatment pipe conduits were buried under the ground next to the stream, which could lead groundwater flow field distortion in this zone. At streambed, the GPR survey and soil coring indicated the presence of low permeable zones consisting of rotten material deposits at the top of 0.3 m ~ 0.8 m underlain by silty sands. These hydrogeological features can also attribute to no detection of contaminants in the streambed and stream water because low permeable zone is an obstacle to effective interactions between groundwater and stream water. More investigations will be carried out for comprehensive understanding of hydrological and biogeochemical processes associated with TCE plume attenuation in near stream zones and streambed in the site.

  6. 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.

  7. 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 ...

  8. 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... within the danger zone during live fire training exercises. The amendment is necessary to protect the... environment and, therefore, preparation of an environmental impact statement is not required. An...

  9. 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.

  10. 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.

  11. Riparian Zones and the Role of Hyporheic Exchange in the Carbon Budget of a Small, Forested, Headwater Stream, Western Oregon, USA.

    NASA Astrophysics Data System (ADS)

    Wondzell, S. M.; Corson-Rikert, H.; Dosch, N.; Haggerty, R.

    2014-12-01

    Recent estimates have identified streams as important conduits in the global carbon budget. Stream waters are typically super-saturated with CO2. This CO2 is assumed to come from carbon fixed in the upland terrestrial environment and then transported to the stream via soil water or groundwater. Evasion of CO2 occurs at the stream surface, which usually comprises less than 2% of the watershed area, yet this flux might account for as much as 30% of the net ecosystem exchange in a watershed. This view does not consider the role of hyporheic exchange, despite the fact that hyporheic exchange fluxes can be very large in headwater streams, which drain the majority of the landscape. Using continuously recording probes, we show that pCO2 averages 890 ppmv in stream water and 7,680 ppmv in hyporheic water in a 96-ha watershed. Independent estimates show that stream water turn-over lengths through the hyporheic zone are less than 100 m at baseflow, which suggests that stream water is continuously recharged with CO2 every time it is cycled through the hyporheic zone. We monitored DIC and DOC in a co-located well network and show that DOC decreases, and DIC increases, with travel time through the hyporheic zone. However, respiration of stream-source DOC can only account for approximately 10% of the increase in DIC. Previous hydrologic studies suggest that lateral inputs of soil water or groundwater are limited within this study reach, so the large increases in DIC must come from particulate organic matter buried in the hyporheic zone and from the overlying soil. These measurements suggest that riparian zones supply, via hyporheic exchange, a disproportionately large fraction of carbon to headwater streams and may therefore play an outsized role in the global carbon cycle.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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

  17. Using Stratasampler{sup {alpha}} Multi-Level Wells to Examine the Hyporheic Zone within a Riparian Wetland

    SciTech Connect

    Dunn, D.L.; Dixon, K.L.; Nichols, R.L.; Schwartzman, A.; Roseberry, R.

    1998-02-01

    The initial objectives of this research are to establish a baseline and monitor the influences of local scale hydrology and biogeochemical behavior within the hyporheic zone at an unimpacted, uncontaminated site.

  18. 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

  19. 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.

    2016-03-01

    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 broadband 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 (LVZ) 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 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 is interpreted as evidence for a possible mantle plume stem originating from the lower mantle.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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 ...

  6. 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...

  7. 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

  8. 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.

  9. An unusual triangle zone in the external northern Alpine foreland (Switzerland): Structural inheritance, kinematics and implications for the development of the adjacent Jura fold-and-thrust belt

    NASA Astrophysics Data System (ADS)

    Malz, Alexander; Madritsch, Herfried; Meier, Beat; Kley, Jonas

    2016-02-01

    Triangle zones represent typical structural elements of thin-skinned foreland fold-and-thrust belts. Here, we report the results of an in-depth structural analysis of a rather unusual triangle zone at the front of the easternmost Jura fold-and-thrust belt in the otherwise only very mildly deformed Alpine foreland of Northern Switzerland. The investigation is based on the interpretation of recently reprocessed and depth-migrated 2D reflection seismic sections. Classical bed-length and area cross-section balancing methods were used to validate the interpretation and unravel the tectonic evolution of the triangle zone. According to our interpretation the analyzed triangle zone formed along the Baden-Irchel-Herdern-Lineament (BIH-Lineament), a regional Paleozoic normal fault that shows evidence of Cenozoic reactivation. The triangle zone is composed of one major foreland-directed thrust rooting in Triassic evaporites and a back-thrust splaying from it in the Middle Jurassic Opalinus Clay, pointing to the importance of secondary detachments. Steeply dipping secondary reverse faults next to the triangle zone suggest reactivation of pre-existing normal faults. The formation of the thrust triangle is considered to relate to thin-skinned foreland deformation in Late Miocene time. Strain estimations of the thrust triangle along-strike show a laterally very uniform amount of shortening, which is in contrast to the southward adjacent Jura fold-and-thrust belt. We interpret this constant shortening to represent the maximum contractional strain attainable by the specific geometry of the BIH triangle zone. At this point, the complex structure became mechanically ineffective and further shortening led to the formation of new contractional structures in its hinterland. This kinematic hypothesis suggests an early-stage formation of the BIH triangle zone followed by back stepping of the deformation front. As such, it challenges the classical view of a purely forward-breaking sequence

  10. 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.

  11. Legal mechanisms for protecting riparian resource values

    SciTech Connect

    Lamb, B.L.; Lord, E. )

    1992-04-01

    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. The authors 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. They discuss the politics of implementing these policies, focusing on the difficulties in changing entrenched water and land use practices. Their 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  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. Multitaxonomic diversity patterns along a desert riparian-upland gradient.

    PubMed

    Soykan, Candan U; Brand, L Arriana; Ries, Leslie; Stromberg, Juliet C; Hass, Christine; Simmons, David A; Patterson, William J D; Sabo, John L

    2012-01-01

    Riparian areas are noted for their high biodiversity, but this has rarely been tested across a wide range of taxonomic groups. We set out to describe species richness, species abundance, and community similarity patterns for 11 taxonomic groups (forbs & grasses, shrubs, trees, solpugids, spiders, scarab beetles, butterflies, lizards, birds, rodents, and mammalian carnivores) individually and for all groups combined along a riparian-upland gradient in semiarid southeastern Arizona, USA. Additionally, we assessed whether biological characteristics could explain variation in diversity along the gradient using five traits (trophic level, body size, life span, thermoregulatory mechanism, and taxonomic affiliation). At the level of individual groups diversity patterns varied along the gradient, with some having greater richness and/or abundance in riparian zones whereas others were more diverse and/or abundant in upland zones. Across all taxa combined, riparian zones contained significantly more species than the uplands. Community similarity between riparian and upland zones was low, and beta diversity was significantly greater than expected for most taxonomic groups, though biological traits explained little variance in diversity along the gradient. These results indicate heterogeneity amongst taxa in how they respond to the factors that structure ecological communities in riparian landscapes. Nevertheless, across taxonomic groups the overall pattern is one of greater species richness and abundance in riparian zones, coupled with a distinct suite of species. PMID:22272224

  18. 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.

  19. 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

    2016-01-01

    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.

  20. 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.

  1. Quantifying Riparian Evapotranspiration 1918

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-disciplinary group of government scientists and university researchers has been working to better understand the hydrological functioning of riparian systems in the Southwest. Perhaps the most socially-relevant facet of this research has been the quantification of riparian evapotranspiratio...

  2. 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. PMID:21520758

  3. 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

  4. 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.

  5. 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

  6. Denitrification and methane/nitrous oxide emissions from recreational and agricultural riparian buffers in the southeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Denitrification was measured via the acetylene inhibition method in riparian buffers adjacent to a golf course and sites with various agronomic management and landscape positions in the southeastern Coastal Plain of the USA. Denitrification in the riparian buffers adjacent to the golf course was neg...

  7. 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.

  8. 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 ...

  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. PMID:25432450

  10. Riparian Land-Use and Rehabilitation: Impact on Organic Matter Input and Soil Respiration

    NASA Astrophysics Data System (ADS)

    Oelbermann, Maren; Raimbault, Beverly A.

    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.

  11. Use of standardized visual assessments of riparian and stream condition to manage riparian bird habitat in eastern Oregon.

    PubMed

    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. PMID:18574622

  12. 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.

  13. 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

  14. Breaking into the Plate: Seismic and Hydroacoustic Analysis of a 7.6 Mw Oceanic Fracture Zone Earthquake Adjacent to the Central Indian Ridge Plate Boundary

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, D. R.; Tolstoy, M.; Chapp, E.

    2003-12-01

    aftershock zone and the centroid location lies within its eastern portion, the rupture appears to have propagated from the plate boundary, breaking into the Indian plate along the fracture zone. The moment tensor solution for the mainshock event indicates dominantly right-lateral slip with a near vertical nodal plane striking parallel to the trend of the aftershocks. The right-lateral sense of slip opposes the left-lateral slip along the adjacent active transform and is consistent with reactivation due to north-south extension in association with a diffuse plate boundary that separates the Indian and Australian Plates. Coulomb failure modeling indicates that the right-lateral mainshock should promote left-lateral slip on the active portions of neighboring transforms. Consistent with this prediction, the largest aftershock, a 5.6 Mw left-lateral earthquake, is located on the active portion of a transform approximately 150 km northwest of the mainshock rupture. These models also show that left-lateral slip on the adjacent active transform, extending southwest from mainshock rupture, should be inhibited. No aftershock activity is observed along this active transform. Static stress changes will tend to reduce ridge-normal compressive stresses along the portion of the CIR axis to the north of the mainshock, with an increase in ridge-normal compression to the south. This will promote and impede axis-parallel diking events within these respective regions.

  15. Riparian indicators of flow frequency in a tropical montane stream network

    NASA Astrophysics Data System (ADS)

    Pike, Andrew S.; Scatena, Frederick N.

    2010-03-01

    SummaryMany field indicators have been used to approximate the magnitude and frequency of flows in a variety of streams and rivers, yet due to a scarcity of long-term flow records in tropical mountain streams, little to no work has been done to establish such relationships between field features and the flow regime in these environments. Furthermore, the transition between the active channel of a river and the adjacent flood zone (i.e. bankfull) is an important geomorphologic and ecological boundary, but is rarely identifiable in steep mountain channels that lack alluvial flood plains. This study (a) quantifies relationships between field indicators and flow frequency in alluvial and steepland channels in a tropical mountain stream network and (b) identifies a reference active channel boundary in these channels, based on statistically defined combinations of riparian features, that corresponds to the same flow frequency of the bankfull stage and the effective discharge in adjacent alluvial channels. The relative elevation of transitions in riparian vegetation, soil, and substrate characteristics were first surveyed at nine stream gages in and around the Luquillo Experimental Forest in Northeastern Puerto Rico. The corresponding discharge, flow frequency, and recurrence intervals associated with these features was then determined from long-term 15-min discharge records and a partial duration series analysis. Survey data indicate that mosses and short grasses dominate at a stage often inundated by sub-effective flows. Herbaceous vegetation is associated with intermediate discharges that correspond to the threshold for sediment mobilization. Near-channel woody shrubs and trees establish at elevations along the channel margin inundated by a less frequent discharge that is coincident with the effective discharge of bed load sediment transport. Our data demonstrate that in alluvial channels in the study, both the bankfull stage (as marked by a flood plain) and the

  16. 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

  17. GROUND COVER IMPACTS ON NITROGEN EXPORT FROM MANURED RIPARIAN BUFFERS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maintaining ground cover of forages may reduce the export of nitrogen (N) from pastures. The objective of this work was to determine the effect of ground cover on N export from pastured riparian areas that received simulated rainfall. Plots were established on two adjacent sites in the North Carol...

  18. 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

  19. 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

  20. Headwater riparian forest-floor invertebrate communities associated with alternative forest management practices.

    PubMed

    Rykken, Jessica J; Moldenke, Andrew R; Olson, Deanna H

    2007-06-01

    Headwater streams and their riparian zones are a common, yet poorly understood, component of Pacific Northwest, USA, landscapes. We describe the ecological importance of headwater stream riparian zones as habitat for forest-floor invertebrate communities and assess how alternative management strategies for riparian zones may impact these communities. We compared community composition of forest-floor invertebrates at increasing distances along trans-riparian (stream edge to upslope) transects in mature forests, clearcuts, and riparian buffers of approximately 30-m width with upslope clearcuts. Invertebrates were collected using pitfall traps in five replicate blocks of three treatments each in the Willamette National Forest, Oregon, USA. We measured microclimate and microhabitat variables at pitfall locations. Despite strong elevation and block effects on community composition, community analyses revealed a distinct "riparian" invertebrate community within 1 m of the stream edge in mature forest treatments, which was strongly related to cool, humid microclimate conditions. Invertebrate community composition in buffer treatments was far more similar to that of mature forests than to clearcuts; a pattern mirrored by microclimate. These results suggest that, within our study sites, forest-floor invertebrate distributions are strongly associated with microclimate and that riparian buffers of approximately 30-m width do provide habitat for many riparian and forest species. Riparian reserves may serve as effective forest refugia and/or dispersal corridors for invertebrates and other taxa, and their incorporation into watershed management plans likely will contribute to meeting persistence and connectivity objectives. PMID:17555226

  1. 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.

  2. 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

  3. 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

  4. NITRATE REMOVAL EFFECTIVENESS OF A RIPARIAN BUFFER ALONG A SMALL AGRICULTURAL STREAM IN WESTERN OREGON

    EPA Science Inventory

    We established two study sites with similar soils and hydrology but contrasting riparian vegetation along Lake Creek, an intermittent stream that drains perennial ryegrass fields in the Willamette Valley of western Oregon. One site had a non-cultivated riparian zone with a plant...

  5. 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...

  6. 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...

  7. 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...

  8. 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.

  9. 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 ...

  10. Time series analysis and the analysis of aquatic and riparian ecosystems

    USGS Publications Warehouse

    Milhous, R.T.

    2003-01-01

    Time series analysis of physical instream habitat and the riparian zone is not done as frequently as would be beneficial in understanding the fisheries aspects of the aquatic ecosystem. This paper presents two case studies have how time series analysis may be accomplished. Time series analysis is the analysis of the variation of the physical habitat or the hydro-period in the riparian zone (in many situations, the floodplain).

  11. 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

  12. Riparian strip efficiency assessment in agricultural landscapes using stereoscopic very high spatial resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Chokmani, Karem; Novoa, Julio

    2015-04-01

    Riparian strips are used worldwide to protect riverbanks and water quality in agricultural zones because of their several environmental benefits. A metric called the Riparian Strip Quality Index, which is based on the percentage area of riverine vegetation found on the riparian strip, is used to evaluate their ecological condition. This index could be considered an indicator of the potential capacity of riparian strips to filter sediments, retain pollutants, and provide shelter to terrestrial and aquatic species. Thus, in order to know if a riparian strip is truly efficient in agricultural lands, which means that it is fulfilling those ecological functions, it is necessary to understand their ability to intercept surface runoff. The latter is the major cause of water pollution and erosion in these productive areas. Besides vegetation coverage, topographic and hydrologic parameters must be included to model the intensity and spatial distribution of runoff streamflow at local scales. The geospatial information used to assess the ecological efficiency of riparian strips was extracted from very-high-spatial-resolution WorldView-2 satellite imagery. This information was then processed using current geospatial techniques such as object-based image analysis and was used to develop a Riparian Strip Efficiency Index. The results show that this index might be used to assess the efficiency of riparian strips, which will enable land managers to monitor changes occurring over time, identify priority areas for restoration activities. This, in turn, might ensure optimal allocation of private or public funds towards the most inefficient and threatened riparian strips.

  13. 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.

  14. VIRGINIA WILDRYE EVALUATIONS IN RIPARIAN ZONES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virginia wildrye (Elymus virginicus L.), a perennial cool-season grass native to the northeastern USA, grows along streams, forest margins, and in other wet areas. Our previous research indicted that Virginia wildrye was not productive as a forage grass compared with introduced species such as orcha...

  15. DEVELOPMENT OF RIPARIAN ZONE INDICATORS (INT. GRANT)

    EPA Science Inventory

    Landscape features (e.g., land use) influence water quality characteristics on a variety of spatial scales. For example, while land use is controlled by anthropogenic features at a local scale, geologic features are set at larger spatial, and longer temporal scales. Individual ...

  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. 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

  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. Experimental studies of aluminum mobility in organic rich riparian soil and stream water in Sweden

    NASA Astrophysics Data System (ADS)

    Wonisch, H.; Cory, N.; Buffam, I.; Laudon, H.; Bishop, K.; Dietzel, M.; Köhler, S. J.

    2009-04-01

    The role of organic acids in mobilizing and controlling aluminum (Al) from a riparian soil profile into a small humic-rich stream draining a forested catchment area was studied in Northern Sweden. Three in-situ soil and stream water manipulation experiments were performed by changing total concentrations of Al and silica while keeping pH constant between 4.8 and 5.6 to decipher the processes regulating stream Al solubility and export. Removal of added silica could not be observed along the 80 m stream reach during the stream manipulation despite a saturation index for Proto-Imogolite higher than 2.5. Removal of dissolved Al and DOC in the stream and the superficial soil solutions of the unsaturated zone occurred at molar Al/DOC ratios above 0.13±0.01. For the lower soil horizons that are in permanent contact with groundwater (45-65 cm) and supply the stream with water during the largest part of the year a ratio above 0.073±0.01 was sufficient to induce Al removal. In all experiments (lab and field) an apparent ion activity product (IAP) for Al(OH)3 of 10.5±0.5 was necessary to induce Al removal. This IAP is rarely reached in the soil solutions or the adjacent stream despite large temporal fluctuations of both TOC and pH during the last 10 years. Al/TOC ratios in both environments are independent of pH and have a constant Al/TOC ratio with minimal variation; 0.013±0.002 (n=61) for the stream and 0.037±0.010 (n=135) for the riparian soil waters within the catchment. The similarities in the riparian soil depth profiles for BaCl2 exchangeable Al and TOC concentrations indicate that the soil organic exchanger complex may explain the small variability of the Al/TOC ratio in the soil. The loss of Al from the soil water during the transport through the riparian zone into the stream might be controlled by organic matter and not an inorganic Al bearing phase. However, to decipher the exact mechanism for the fixation of more than 70% of the soil solution Al in the

  20. 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.

  1. 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

  2. Toward efficient riparian restoration: integrating economic, physical, and biological models.

    PubMed

    Watanabe, Michio; Adams, Richard M; Wu, Junjie; Bolte, John P; Cox, Matt M; Johnson, Sherri L; Liss, William J; Boggess, William G; Ebersole, Joseph L

    2005-04-01

    This paper integrates economic, biological, and physical models to explore the efficient combination and spatial allocation of conservation efforts to protect water quality and increase salmonid populations in the Grande Ronde basin, Oregon. We focus on the effects of shade on water temperatures and the subsequent impacts on endangered juvenile salmonid populations. The integrated modeling system consists of a physical model that links riparian conditions and hydrological characteristics to water temperature; a biological model that links water temperature and riparian conditions to salmonid abundance, and an economic model that incorporates both physical and biological models to estimate minimum cost allocations of conservation efforts. Our findings indicate that conservation alternatives such as passive and active riparian restoration, the width of riparian restoration zones, and the types of vegetation used in restoration activities should be selected based on the spatial distribution of riparian characteristics in the basin. The relative effectiveness of passive and active restoration plays an important role in determining the efficient allocations of conservation efforts. The time frame considered in the restoration efforts and the magnitude of desired temperature reductions also affect the efficient combinations of restoration activities. If the objective of conservation efforts is to maximize fish populations, then fishery benefits should be directly targeted. Targeting other criterion such as water temperatures would result in different allocations of conservation efforts, and therefore are not generally efficient. PMID:15763152

  3. 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.

  4. 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.

  5. Influence of Herbaceous Riparian Buffers on Fish and Amphibian Communities Within Channelized Headwater Streams in Central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbaceous riparian buffers are a widely used conservation practice in the United States for reducing nutrient, pesticide, and sediment loadings in agricultural streams. The importance of forested riparian zones for headwater streams has been documented, but the ecological impacts of herbaceous ripa...

  6. 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...

  7. Nitrate removal effectiveness of a riparian buffer along a small agricultural stream in western Oregon.

    PubMed

    Wigington, P J; Griffith, S M; Field, J A; Baham, J E; Horwath, W R; Owen, J; Davis, J H; Rain, S C; Steiner, J J

    2003-01-01

    The Willamette Valley of Oregon has extensive areas of poorly drained, commercial grass seed lands. Little is know about the ability of riparian areas in these settings to reduce nitrate in water draining from grass seed fields. We established two study sites with similar soils and hydrology but contrasting riparian vegetation along an intermittent stream that drains perennial ryegrass (Lolium perenne L.) fields in the Willamette Valley of western Oregon. We installed a series of nested piezometers along three transects at each site to examine NO3-N in shallow ground water in grass seed fields and riparian areas. Results showed that a noncultivated riparian zone comprised of grasses and herbaceous vegetation significantly reduced NO3-N concentrations of shallow ground water moving from grass seed fields. Darcy's law-based estimates of shallow ground water flow through riparian zone A/E horizons revealed that this water flowpath could account for only a very small percentage of the streamflow. Even though there is great potential for NO3-N to be reduced as water moves through the noncultivated riparian zone with grass-herbaceous vegetation, the potential was not fully realized because only a small proportion of the stream flow interacts with riparian zone soils. Consequently, effective NO3-N water quality management in poorly drained landscapes similar to the study watershed is primarily dependent on implementation of sound agricultural practices within grass seed fields and is less influenced by riparian zone vegetation. Wise fertilizer application rates and timing are key management tools to reduce export of NO3-N in stream waters. PMID:12549555

  8. 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.

  9. 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

  10. 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.

  11. Riparian vegetation and water yield: A synthesis

    NASA Astrophysics Data System (ADS)

    Salemi, Luiz Felippe; Groppo, Juliano Daniel; Trevisan, Rodrigo; Marcos de Moraes, Jorge; de Paula Lima, Walter; Martinelli, Luiz Antonio

    2012-08-01

    SummaryForested riparian zones perform numerous ecosystem functions, including the following: storing and fixing carbon; serving as wildlife habitats and ecological corridors; stabilizing streambanks; providing shade, organic matter, and food for streams and their biota; retaining sediments and filtering chemicals applied on cultivated/agricultural sites on upslope regions of the catchments. In this paper, we report a synthesis of a different feature of this type of vegetation, which is its effect on water yield. By synthesizing results from studies that used (i) the nested catchment and (ii) the paired catchment approaches, we show that riparian forests decrease water yield on a daily to annual basis. In terms of the treated area increases on average were 1.32 ± 0.85 mm day-1 and 483 ± 309 mm yr-1, respectively; n = 9. Similarly, riparian forest plantation or regeneration promoted reduced water yield (on average 1.25 ± 0.34 mm day-1 and 456 ± 125 mm yr-1 on daily and annual basis, respectively, when prorated to the catchment area subjected to treatment; n = 5). Although there are substantially fewer paired catchment studies assessing the effect of this vegetation type compared to classical paired catchment studies that manipulate the entire vegetation of small catchments, our results indicate the same trend. Despite the occurrence of many current restoration programs, measurements of the effect on water yield under natural forest restoration conditions are still lacking. We hope that presenting these gaps will encourage the scientific community to enhance the number of observations in these situations as well as produce more data from tropical regions.

  12. 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.

  13. 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

  14. Carbon and nitrogen dynamics in a soil profile: Model insights and application to a restored Swiss riparian area

    NASA Astrophysics Data System (ADS)

    Brovelli, Alessandro; Batlle-Aguilar, Jordi; Luster, Jörg; Shrestha, Juna; Huber, Benjamin; Niklaus, Pascal; Barry, D. Andrew

    2010-05-01

    The key environmental importance of natural, healthy ecosystems has been progressively recognized and restoration of degraded lands towards their former natural state has become an area of active research worldwide. During restoration, environmental conditions (such as vegetation type and water availability) are manipulated to create ecological conditions suitable for the successful establishment of a target composition of species. Often, ecological restoration induces changes to adjacent ecosystems. This is the case of riparian ecosystems, and their restoration to their original undisturbed situation is likely to cause changes in nutrient cycles. For example, following the restoration of a riparian zone, microbial communities adapted to one set of environmental conditions have to acclimatize to another, and the subsequent changes in the composition of the biomass populations might induce changes in soil organic matter mineralization and soil respiration rates. Since the biogeochemical cycles are tightly interconnected, these changes can trigger nutrient storing or release, therefore inducing changes in nutrient cycles of adjacent ecosystems. Overall, the effects of the restoration activities on the hydrologic regime, soil properties and vegetation are still largely unknown and poorly understood. Within the RECORD project (http://www.cces.ethz.ch/projects/nature/Record), a large collaborative research effort undertaken to monitor and understand the changes in ecosystem functioning in riparian areas undergoing restoration, a numerical model has been developed to simulate the vertical transport of the mobile C and N components in a soil profile (model development discussed in the companion submitted abstract Batlle-Aguilar et al.). In the model, microbial decomposition of the soil organic matter drives biogeochemical transformations of C and N, while the activity of the soil biota is primarily controlled by the soil moisture content. The temporal evolution of the

  15. Push-pull tests to determine in-situ nitrogen processing in groundwaters of a tropical riparian forest, Luquillo Mountains, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Brereton, R. L.

    2012-12-01

    Riparian zones are biogeochemical hot spots known to control the flux of dissolved nitrogen (N) from groundwater to surface waters by providing favorable conditions for N removal and retention. In many watersheds with agricultural or urban inputs, N enters groundwater after being leached from soils in the form of nitrate, which is then removed from solution by denitrification in the anoxic riparian groundwater. Certain tropical forested watersheds, however, display spatial patterns in groundwater N chemistry that cannot be explained by simple denitrification. High ammonium concentrations (>0.5 mg/L), in comparison to other reference watersheds, exist in groundwaters directly adjacent to streams carrying little or no ammonium. The N speciation is accompanied by dramatic shifts in redox conditions from hillslope to riparian zone to stream. A valuable ecosystem service is being provided by these tropical ecosystems but that service has not been adequately described by science. What is the source and fate of this ammonium? The push-pull test is a recently developed method to determine in-situ reaction rates by the addition of reactive substrates and a conservative tracer to groundwater, followed by an incubation period and sampling over time. In the Rio Icacos watershed in the Luquillo Experimental Forest of Puerto Rico, push-pull tests were conducted to determine the reaction pathways of ammonium production and consumption. Shallow groundwater wells (1-4 m below soil surface) in a riparian zone of a tributary the Rio Icacos were tested in two locations: immediately adjacent to the stream and at the topographic break between the hillslope and the floodplain. 10 L "push" solutions with ammonium, nitrate, or both and a chloride or bromide tracer were added and incubated over a 20-40 hr period (depending on the hydraulic conductivity of the individual well). Initial results were consistent with coupled nitrification-denitrification occurring at both the hillslope

  16. 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

  17. 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

  18. Petrology and Geochemistry of Tethyan Mélange and Flysch Units Adjacent to the Yarlung Zangbo Suture Zone (YZSZ), Southern Tibet

    NASA Astrophysics Data System (ADS)

    Dupuis, C.; Hebert, R.; Wang, C.; Li, Y.; Li, Z.

    2004-05-01

    Located north of the Himalayas, the E-W trending YZSZ is mainly composed of remnants of the Neo-Tethys ocean-floor and marks the suture between Indian and Eurasian plates. This project aims to define geological units immediately South of the YZSZ ophiolites : the serpentinized ophiolitic mélange, the Jurassic-Cretaceous wildflysch and the Triassic flysch. The ophiolitic mélange is characterized by ultramafic rocks, which can be divided into 3 groups. Cpx-harzburgites contain brownish aluminous spinels with Mg# of 0.7-0.75 and Cr# of 0.15-0.27. They resemble fertile abyssal peridotites with generally smooth LREE-depleted and fairly flat MREE-HREE profiles. Transitional harzburgites contain reddish spinels with Mg# of 0.57-0.66 and Cr# of 0.35-0.46. They resemble depleted abyssal or supra-subduction zone peridotites in that MREE-HREE profiles have positive slopes indicative of high degrees of partial melting. LREE profiles vary from depleted to slightly enriched, consistent with some trapped or interacting melt or aqueous fluids. Harzburgites and dunites contain dark reddish spinels with Mg# of 0.47-0.68 and Cr# of 0.40-0.63. They have U-shaped profiles characteristics of interaction between LREE-enriched melt and REE-depleted mantle residues. Spinel compositions and fractional melting modelling indicate that Cpx-harburgites may be the residues from 5-15% melting, transitional harzburgites from 15-23% melting, and harzburgites and dunites from 22-29% melting. The South Sandwich arc-basin system is considered a modern analog of initial geodynamic setting. Mafic rocks (gabbros, diabases and basalts) are ubiquitous and can be geochemically subdivided according to their source unit. LREE-depleted profiles with average (La/Yb)N of 0.5 and slight negative Nb-Ta and Ti anomalies indicate that rocks from the ophiolitic mélange formed in a back-arc basin, such as back-arc-basin mafic rocks of the Izu-Bonin Arc. REE patterns of rocks from the wildflysch are LREE

  19. 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.

  20. 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.

  1. 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. PMID:12105980

  2. 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

  3. Enhanced transpiration by riparian buffer trees in response to advection in a humid temperate agricultural landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  4. 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

  5. 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

  6. 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

  7. Basic principles and ecological consequences of changing water regimes: riparian plant communities.

    PubMed

    Nilsson, Christer; Svedmark, Magnus

    2002-10-01

    Recent research has emphasized the importance of riparian ecosystems as centers of biodiversity and links between terrestrial and aquatic systems. Riparian ecosystems also belong among the environments that are most disturbed by humans and are in need of restoration to maintain biodiversity and ecological integrity. To facilitate the completion of this task, researchers have an important function to communicate their knowledge to policy-makers and managers. This article presents some fundamental qualities of riparian systems, articulated as three basic principles. The basic principles proposed are: (1) The flow regime determines the successional evolution of riparian plant communities and ecological processes. (2) The riparian corridor serves as a pathway for redistribution of organic and inorganic material that influences plant communities along rivers. (3) The riparian system is a transition zone between land and water ecosystems and is disproportionately plant species-rich when compared to surrounding ecosystems. Translating these principles into management directives requires more information about how much water a river needs and when and how, i.e., flow variables described by magnitude, frequency, timing, duration, and rate of change. It also requires information about how various groups of organisms are affected by habitat fragmentation, especially in terms of their dispersal. Finally, it requires information about how effects of hydrologic alterations vary between different types of riparian systems and with the location within the watershed. PMID:12481914

  8. Riparian invasive alters stream nitrogen dynamics.

    NASA Astrophysics Data System (ADS)

    Mineau, M.; Baxter, C.; Marcarelli, A.; Minshall, G.

    2008-12-01

    Invasive species may be most likely to have strong effects on the ecosystem they invade when they contribute a new function such as nitrogen (N) fixation. Russian olive (Eleagnus angustifolia) is a non-native invasive tree which is rapidly spreading along riparian corridors in the American West. Russian olive is a nitrogen fixing plant due to a symbiotic relationship with Actinomycetes and is invading systems that frequently lack a strong native N fixer. The contribution of reactive N by these invasive riparian plants to soils may also be altering N cycling and processing in the adjacent streams. We measured nutrient limitation via periphyton growth on nutrient diffusing substrates and nitrate uptake using short term nitrate additions in Deep Creek, ID. Measurements were made in three reaches along a Russian olive invasion gradient, with an upstream reference reach that has no Russian olive and two downstream invaded reaches, one with moderate density and one with high density. Periphyton growth in Deep Creek was significantly N limited in the reference reach while the moderately invaded reach showed no significant limitation and the highly invaded reach was significantly P limited. The nitrate uptake velocity (Vf) for both of the invaded reaches was an order of magnitude less than the reference reach, implying that biological demand for nitrate is significantly less in the invaded reaches than the reference. Considering the current extent of Russian olive invasion and its continued rapid spread, possible alteration of N cycling in waterways may have important implications for the management of both this invasive species and management of nutrient pollution in waters of the western U.S.

  9. 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

  10. 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

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

    USGS Publications Warehouse

    Peak, R.G.; Thompson, F. R., III; 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

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

    USGS Publications Warehouse

    Peak, R.G.; Thompson, F. R., III; 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

  13. 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

  14. Nitrogen and Sediment Inputs to the San Pedro River Riparian Area

    NASA Astrophysics Data System (ADS)

    Conklin, M.; Huth, A. K.; Hamblen, J.; Villinski, J.; Grimm, N.; Lewis, D.; Schade, J.

    2002-05-01

    The San Pedro River in southern Arizona is the last undammed major river in the Western U.S. The riparian habitat along the upper San Pedro is under pressure due to competing water use by nearby agriculture and municipal demands. Numerous nongovernmental organizations and government agencies are cooperating to investigate the functioning of the riparian area, including water and nutrient cycling. The multi-institutional NSF Science and Technology Center for Sustainability of semi-Arid Hydrology and Riparian Areas (SAHRA) is using two 500-m study sites along the upper San Pedro River (one gaining and one losing-intermittent) to investigate nutrient and sediment fluxes. Sampling of over 80 shallow piezometers installed in the stream, in gravel bars and in riparian terraces (among cottonwoods and willows) showed nitrate levels were highest in the riparian terrace and gravel bars throughout the year. Nitrate levels in shallow stream piezometers were lower and more variable. Seasonal algal blooms were correlated with decreases in nitrate and organic nitrogen in the stream channel. Intensive sampling during a 300 cfs flood (July 17-18, 2001) in the intermittant-losing reach showed significant increases in nitrate levels during the storm, apparently from the gravel bars and riparian terrace. Hydrograph separation indicated a substantial fraction of the water in the river had been in contact with the river banks. During storm events, substantial sediment transport occurs, as well as scour and fill. As much of the nitrogen cycling in microbially controlled, sediment scour and fill is being monitored concomitantly with respiration measurements in a meander point bar in the losing-intermittant reach. By focusing on key processes in the shallow stream sediments, gravel bars and riparian terraces, we are establishing linkages between the different zones of the riparian area in order to characterize nitrogen uptake capacity of the riparian system.

  15. 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.

  16. Transport in a three-zone wetland: Flow velocity profile and environmental dispersion

    NASA Astrophysics Data System (ADS)

    Wang, P.; Chen, G. Q.; Jiang, C. B.; Alsaedi, A.; Wu, Z.; Zeng, L.

    2015-01-01

    To achieve better understanding of transport process in real waterways interacted with adjacent aquatic vegetation and riparian buffers, a three-zone model featuring the bank-effect is presented to character the water flow and environmental dispersion. Based on basic formulation in context of porous media flow, the velocity profile of a fully developed flow through the wetland is derived, with that for single zone and two-zone wetland flows recovered as special cases. The environmental dispersivity is determined by the approach of multi-scale analysis, with the effects of dimensionless parameters well illustrated. Application examples are provided to illustrate associated hierarchical structure for the critical length and duration of the contaminant cloud, and a comparison is made between the three-zone wetland and a corresponding three-layer wetland.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. 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.

  3. 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.

  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. 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.

  6. 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

  7. Interplay of riparian forest and groundwater in the hillslope hydrology of Sudanian West Africa (northern Benin)

    NASA Astrophysics Data System (ADS)

    Richard, A.; Galle, S.; Descloitres, M.; Cohard, J.-M.; Vandervaere, J.-P.; Séguis, L.; Peugeot, C.

    2013-12-01

    Forests are thought to play an important role in the regional dynamics of the West African monsoon, through their capacity to extract water from a permanent and deep groundwater table to the atmosphere even during the dry season. It should be the case for riparian forests too, as these streambank forests are key landscape elements in Sudanian West Africa. The interplay of riparian forest and groundwater in the local hydrodynamics was investigated, by quantifying their contribution to the water balance. Field observations from a comprehensively instrumented hillslope in northern Benin were used. Particular attention was paid to measurements of actual evapotranspiration, soil water and deep groundwater levels. A vertical 2-D hydrological modelling approach using the Hydrus software was used as a testing tool to understand the interactions between the riparian area and the groundwater. The model was calibrated and evaluated using a multi-criteria approach (reference simulation). A virtual experiment, including three other simulations, was designed (no forest, no groundwater, neither forest nor groundwater). The model correctly simulated the hydrodynamics of the hillslope regarding vadose zone dynamics, deep groundwater fluctuation and actual evapotranspiration dynamics. The virtual experiment showed that the riparian forest transpiration depleted the deep groundwater table level and disconnected it from the river, which is consistent with the observations. The riparian forest and the deep groundwater table actually form an interacting transpiration system: the high transpiration rate in the riparian area was shown to be due to the existence of the water table, supplied by downslope lateral water flows within the hillslope soil layer. The simulated riparian transpiration rate was practically steady all year long, around 7.6 mm d-1. This rate lies within high-end values of similar study results. The riparian forest as simulated here contributes to 37% of the annual

  8. 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

  9. 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

  10. 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. PMID:25192194

  11. 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

  12. 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

  13. 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

  14. 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, III; 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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

  20. Dairy farm impacts of fencing riparian land: pasture production and farm productivity.

    PubMed

    Aarons, Sharon R; Melland, Alice R; Dorling, Lianne

    2013-11-30

    Dairy farmers are encouraged to restrict stock access by fencing riparian zones to reduce stream pollution and improve biodiversity. Many farmers are reluctant to create fenced riparian zones because of the perceived loss of productive pasture. Anecdotal reports indicate that pasture production in fenced areas is especially valued during summer months when water stress is likely to limit pasture growth in other areas of the farm. We measured pasture production, botanical composition, soil moisture, and fertility in Riparian (within 20 m of the riverbank), Flat (greater than 20 but less than 50 m from the riverbank), and Hill (elevated) areas on three commercial dairy farms from October 2006 to November 2007 in south eastern Australia. Riparian and Flat areas produced significantly more pasture, with on average approximately 25% more dry matter per ha grown in these areas compared with Hill paddocks. Percentage ryegrass was 14% lower on Hill slopes compared with Riparian and Flat areas and was compensated for by only a 5% increase in other grass species. Significant seasonal effects were observed with the difference in pasture production between Hill, and Riparian and Flat areas most pronounced in summer, due to soil moisture limitations on Hill paddocks. To examine potential productivity impacts of this lost pasture, we used a questionnaire-based survey to interview the farmers regarding their farm and riparian management activities. The additional pasture that would have been available if the riverbanks were not fenced to their current widths ranged from 6.2 to 27.2 t DM for the 2006/2007 year and would have been grown on 0.4-3.4% of their milking area. If this pasture was harvested instead of grazed, the farmers could have saved between $2000 and $8000 of their purchased fodder costs in that year. By fencing their riparian areas to 20 m for biodiversity benefits, between 2.2% and 9.8% of their milking area would be out of production amounting to about $16

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:21385181

  7. 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.

  8. 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

  9. 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.

  10. Trapping efficiencies of cultivated and natural riparian vegetation of northern Laos.

    PubMed

    Vigiak, Olga; Ribolzi, Olivier; Pierret, Alain; Sengtaheuanghoung, Oloth; Valentin, Christian

    2008-01-01

    In northern Laos, intensification of cultivation on sloping land leads to accelerated erosion processes. Management of riparian land may counteract the negative impacts of higher sediment delivery rates on water quality. This study assessed water and sediment concentration trapping efficiencies of riparian vegetation in northern Laos and the effect of cultivation of riparian land on water quality. Runoff flowing in and out of selected riparian sites was monitored by means of open troughs. In 2005, two native grass, two bamboo, and two banana sites were monitored. In 2006, adjacent to steep banana, bamboo, and native grass sites, three upland rice sites were established and monitored. Water trapping efficiency (WTE) and sediment concentration trapping efficiency (SCTE) were calculated on an event basis; means and 95% confidence intervals (CIs) were estimated with a bootstrapping approach. Confidence intervals were large and overlapping among sites. Seepage conditions severely limited trapping efficiency. Native grass resulted in the highest WTE (95% CI, -0.10 to 0.23), which was not significantly different from zero. Banana resulted in the highest SCTE (95% CI, 0.06-0.40). Bamboo had negative WTE and SCTE. Median outflow runoff from rice sites was nine times the inflow. Median outflow sediment concentration from rice sites was two to five times that of their adjacent sites and two to five times the inflow sediment concentration. Although low-tillage banana plantation may reduce sediment concentration of runoff, cultivation of annual crops in riparian land leads to delivery of turbid runoff into the stream, thus severely affecting stream water quality. PMID:18453411

  11. 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

  12. 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

  13. 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.

  14. 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

  15. Hydrology of a Riparian Wetland in the Adirondacks of New York State

    NASA Astrophysics Data System (ADS)

    Newton, R. M.; Hodo, R. M.; Pufall, A.

    2001-12-01

    A riparian wetland in the Sunday Lake watershed located in the western Adirondack region of New York State was instrumented as part of a study of mercury in Adirondack wetlands, lakes and terrestrial systems. Multiple arrays of shallow groundwater piezometers were installed adjacent to the inlet stream and along the shore of Sunday Lake. Four dataloggers equipped with pressure transducers continuously monitor groundwater stage at 4 of the piezometers and surface water stage at 3 gage stations. In addition, rainfall (tipping bucket), air temperature and water temperature (thermisters) are also monitored at these sites. Water samples are taken monthly from all piezometers and surface waters and analyzed for major ion chemistry as well as 18O and deuterium. Head measurements show that the riparian wetlands discharge water to the streams from surrounding areas of stratified drift throughout most of the year. During baseflow periods in the growing season, water levels in piezometers display a daily oscillation in stage of as much as 3 cm due to evapotranspiration. During hydrologic events the groundwater flow system in the riparian wetland can be reversed with water from the stream flowing into the groundwater system. Groundwater hydrographs show a rapid rise in stage associated with rapid infiltration from rainfall or snowmelt events. This is immediately followed by a rapid decline and then a slow rise. The slow rise appears to be due to infiltration of stream water into the groundwater during peak stream flow. The peak in the stream hydrograph occurs well after (10-12 hrs) the initial rise in groundwater stage. The reversal of hydraulic gradient during the peak stream flow extends completely across the riparian wetland and a rise in groundwater stage due to stream infiltration has been detected in piezometers located as far as 30 meters from the stream. The shallow riparian groundwater, like the surface waters, is chemically dilute (specific conductance <40 μ S

  16. 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

  17. 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

  18. Dynamics of riparian wetlands and stream flow generation in montane watersheds

    NASA Astrophysics Data System (ADS)

    Piegat, K.; Tetzlaff, D.; McDonnell, J. J.; Soulsby, C.

    2011-12-01

    Previous work in the Scottish Highlands has shown that the dynamic expansion and contraction of riparian wetlands exerts a dominant control on the delivery of storm runoff to channel networks. However, the way in which hillslope subsurface flow connects to these wetlands is poorly understood. Consequently, although saturation overland flow from these wetlands is a dominant storm runoff process, it is unclear to what extent this is controlled by direct precipitation inputs or exfiltration of hillslope groundwaters. This contribution reports a multivariate study of a 3.2km2 watershed that integrates hydrometric and isotopic characterisation of soil and groundwater in riparian wetlands. The investigation focuses on internal processes of water partitioning, storage, and release along a hillslope transect encompassing three main hydrological response units. The units are based on the UK HOST (Hydrology of Soil Type) hydropedological classification system, and grade from freely draining steep uplands with podzolic soils, through a transitional zone of peaty gley soils in lower slopes and then riparian wetlands dominated by deeper peat. Preliminary results indicate that high moisture retention in the peaty soils and low hydraulic gradients maintain saturated or near-saturated conditions even during drier periods. Thus expansion of saturation zones occurs rapidly in response to direct precipitation and generates overland flow, though this is mainly generated by pre-event water. However, transient rises in groundwater tables in upslope areas also contribute to the storm period recession, and hillslope groundwater drainage continues to feed the riparian wetlands during baseflows.

  19. 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.

  20. How Riparian Vegetation Influences Stream Morphology and Process: Implications for Restoration

    NASA Astrophysics Data System (ADS)

    Pizzuto, J. E.

    2005-05-01

    Vegetation is often used to enhance bank stabilization efforts and as part of more generalized restoration designs, but the influence of vegetation on geomorphic processes is poorly understood. Recent research suggests that changes in riparian vegetation can influence channel morphology, rates of erosion and deposition, and by extension, the entire sediment budget of a reach. In recent studies in the Mid-Atlantic region, reaches with forested riparian vegetation were compared to immediately adjacent non-forested (grassy) riparian vegetation to explain why channels with forested vegetation are wider than their non-forested counterparts. At study sites, erosion occurs at cutbanks in curving reaches, while deposition is localized on active floodplains at the insides of bends. In narrow, non-forested reaches, rates of bank erosion and channel migration are high, while in wide, forested reaches, rates of bank erosion and channel migration are low. These results may be explained using the ratio of two dimensionless parameters, alpha and E. Alpha represents the influence of vegetation on rates of active floodplain deposition (it is very high in non-forested reaches, and very low in forested reaches), while E is proportional to rates of cutbank migration (it is high in non-forested areas and low in forested areas). The width is proportional to E/alpha. These results could lead to improved assessment of the geomorphic effects of restoration designs that involve changes in riparian vegetation.

  1. Assessing water quality at large geographic scales: relations among land use, water physicochemistry, riparian condition, and fish community structure.

    PubMed

    Meador, Michael R; Goldstein, Robert M

    2003-04-01

    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 basinwide 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. PMID:12677296

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Comparison of the Phosphorus Sorption Characteristics of a Conservation Reserve Buffer and an Adjacent Crop Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The United States Department of Agriculture’s Conservation Reserve Program (CRP) was established by the Food Security Act of 1985. Since its inception, thousands of acres of cropland in stream riparian zones have been converted to conservation buffers through the planting of trees and native grasses...

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Influence of Riparian Habitat and Nutrients on Aquatic Communities Within Riparian Zones of Headwater Streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Headwater streams are the smallest streams in a watershed. Their small size and high frequency of occurrence make them susceptible to anthropogenic habitat alterations. Many headwater streams in the Midwestern United States have been channelized to drain agricultural fields. Aquatic macroinvertebrat...

  13. Estimating Riparian ET through Remote Sensing

    NASA Astrophysics Data System (ADS)

    Samani, Z.; Bawazir, S.; Bleiweiss, M.; Skaggs, R.; Schmugge, T.

    2005-12-01

    Riparian evapotranspiration (ET) along the Rio Grande River has become a major hydrological as well as political issue in New Mexico. The State of New Mexico has spent millions of dollars in recent years to eradicate riparian vegetation without being able to quantify the change in regional ET. Many studies have focused on measuring evapotranspiration of individual riparian vegetation types, mainly saltcedar and native cottonwood. However, the riparian vegetation on the Middle Rio Grande varies in density and species.. Spatial variation in climate, soil type and depth to groundwater causes variation in ET, as well. It is obvious that in order to obtain more accuracy in measurements, multiple sampling points are needed; thus, making the process costly and impractical An alternative solution, which is also cost-effective, is measuring ET by using remote sensing technology. Remote sensing combines regional satellite data with localized ET measurement to calculate regional ET. REEM (Regional ET Estimation Model) is a process that uses the energy balance at the top of the canopy to estimate ET. REEM has been using ASTER images for values of surface temperature, albedo and NDVI to calculate net radiation (Rn), ground heat flux (G) and sensible heat flux (H). The ET is then calculated as residual of the energy components. The REEM model is being used to calculate regional ET values for the Riparian vegetation of the Middle Rio Grande. The paper compares the ET values for various vegetation types using remote sensing and ET derived from Eddy Covariance Flux Towers.

  14. Interannual trends in water use efficiency in declining riparian woodlands

    NASA Astrophysics Data System (ADS)

    Stella, J. C.; Riddle, J. D.; Piégay, H.; Teece, M.; Trémelo, M.

    2012-12-01

    Riparian ecosystems in water limited regions are under stress worldwide from flow regulation, land use and climate change. We analyzed tree-ring growth and stable carbon isotope geochemistry in pioneer trees to identify shifts in riparian tree water use as it affects forest condition. We cored individuals of Populus nigra, a riparian species that is vulnerable to changes in local groundwater levels, at floodplain sites along the Drôme River, in the Mediterranean-climate zone of southern France, to analyze the relative ecological impacts of in-stream gravel mining and climate-induced flow reductions on tree growth, crown dieback, and ecohydrological function. Regime Shift Detection analysis of site chronologies showed a divergent pattern among sites, with four sites maintaining stable growth and three others with sharply declining trends in growth to less than 30 cm2 basal area increment (BAI) in all recent years. At sites with stable growth, there was a negative relationship between growth and δ13C (slope = -0.37 to -0.55, p<0.01), indicating that the highest growth occurred when water was abundant. At declining sites, there was a positive relationship between growth and δ13C (slope = 0.33 to 0.52, p<0.01). These trends suggest that the highest water stress occurred in high growth years, and is consistent with limited groundwater capacity. Trees with the greatest crown dieback evident from low-altitude aerial photos had the greatest increase in water use efficiency. Growth declines and increased 13C enrichment were initiated in years of meteorological droughts that occurred after (but never prior to) the mining period, and were spatially distributed to suggest local bedrock controls on soil depth. The combined results indicate that these semi-arid riparian woodlands are vulnerable to multiple physical drivers, but that the severity of impacts is conditioned by interactions between drivers at different scales, including regional climate variability, reach

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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...

  1. 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...

  2. MULTISTAGE CHARACTERIZATION OF RIPARIAN PATCHES IN THE ARID SOUTHWEST

    EPA Science Inventory

    Some ecologically critical riparian ecosystems in the and Southwest are spatially and temporally discontinuous making their location and/or condition difficult to distinguish when studying the desert landscape. When conditions permit, riparian patches in the desert are distinct b...

  3. 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...

  4. 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

  5. Root Allocation and Water Uptake Patterns in Riparian Tree Saplings: responses to irrigation and defoliation in a glasshouse environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Populus is often the focus of restoration efforts in riparian ecosystems. Its reliance on shallow groundwater tables for successful recruitment is well documented. However, under some circumstances mature trees take up a substantial proportion of their water from the unsaturated zone. From...

  6. 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...

  7. A scientific assessment of the effectiveness of riparian management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The CEAP Riparian Team reviewed the influence of riparian management practices (RMP) on vegetation, soils and ecosystem services. We developed a conceptual model that links management practices to riparian vegetation and soil attributes and then links these attributes to ecosystem services such as w...

  8. 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…

  9. 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.

  10. 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...

  11. ASSESSING NITROGEN CYCLING MECHANISMS TO EVALUATE RIPARIAN ZONE RESTORATION EFFECTIVENESS

    EPA Science Inventory

    Agricultural and forestry practices, point source pollution, and urban development have had considerable impacts on nitrogen cycling and water quality in many developed and agricultural regions of the world. Among these impacts are eutrophication due to nutrient loading and oxyge...

  12. 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...

  13. 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

  14. Methods for evaluating riparian habitats with applications to management

    USGS Publications Warehouse

    Platts, William S.; Armour, C.L.; Booth, G.D.; Bryant, M.; Bufford, J.L.; Cuplin, P.; Jensen, S.; Lienkaemper, G.W.; Minshall, G.W.; Monsen, S.T.; Nelson, R.L.; Sedell, J.R.; Tuhy, J.S.

    1987-01-01

    Riparian area planning and management is a major national issues today--something that should have been the case a century ago. A century of additive effects of land use has resulted in major impacts on many riparian stream habitats and their fisheries, wildlife, and domestic livestock use. Before scientists can evaluate the influences of various land and water uses on riparian environments, they must first understand these environments. This means being able to detect and measure with confidence the natural and artificial variation and instantaneous conditions of the riparian habitat. These conditions must then be related to the production capability of riparian habitat and any extraneous factors affecting this production potential.

  15. HERBICIDE ABATEMENT BY A RIPARIAN WETLAND SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are touted for their ability to remove agricultural contaminants; however, little is known about the specific processes that function to arrest pesticide movement and transport. Five years of data have been gathered on the movement and fate of atrazine and metolachlor into a ripari...

  16. Herbicide Abatement by a Riparian Wetland System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are touted for their ability to remove agricultural contaminants. However, little is known about the specific processes that function to arrest pesticide movement and transport. Five years of data have been gathered on the movement and fate of atrazine and metolachlor into a ripar...

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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. PMID:22370391

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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%.

  10. Floodflow effects on riparian vegetation in Arizona

    USGS Publications Warehouse

    Phillips, J.V.; Hjalmarson, H.W.

    1994-01-01

    A relation for estimating changes in the condition of riparian vegetation as a function of stream power was developed for stream channels in central Arizona. Flood and vegetation data were collected from 13 flows at 11 sites. Stream power was computed at cross sections and plotted against the average height of vegetation for each flow. The effect of the flow - no effect, little effect, laid over, or removed - on the riparian vegetation is related to stream power and vegetation height. As vegetation height increases, the magnitude of stream power needed to affect the vegetation also increases. Stream power of about 72 Newton-meters per second per meter squared is needed to lay over 1-meter-high vegetation, and stream power of about 580 Newton-meters per second per meter squared is needed to lay over 5.5-meter-high vegetation. This relation can be used to estimate vegetation conditions at the time of peak floodflow.

  11. 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.

  12. 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.

  13. Precipitation v. River Discharge Controls on Water Availability to Riparian Trees in the Rhône River Delta

    NASA Astrophysics Data System (ADS)

    Singer, M. B.; Sargeant, C. I.; Vallet-Coulomb, C.; Evans, C.; Bates, C. R.

    2014-12-01

    Water availability to riparian trees in lowlands is controlled through precipitation and its infiltration into floodplain soils, and through river discharge additions to the hyporheic water table. The relative contributions of both water sources to the root zone within river floodplains vary through time, depending on climatic fluctuations. There is currently limited understanding of how climatic fluctuations are expressed at local scales, especially in 'critical zone' hydrology, which is fundamental to the health and sustainability of riparian forest ecosystems. This knowledge is particularly important in water-stressed Mediterranean climate systems, considering climatic trends and projections toward hotter and drier growing seasons, which have the potential to dramatically reduce water availability to riparian forests. Our aim is to identify and quantify the relative contributions of hyporheic (discharge) water v. infiltrated precipitation to water uptake by riparian Mediterranean trees for several distinct hydrologic years, selected to isolate contrasts in water availability from these sources. Our approach includes isotopic analyses of water and tree-ring cellulose, mechanistic modeling of water uptake and wood production, and physically based modeling of subsurface hydrology. We utilize an extensive database of oxygen isotope (δ18O) measurements in surface water and precipitation alongside recent measurements of δ18O in groundwater and soil water and in tree-ring cellulose. We use a mechanistic model to back-calculate source water δ18O based on δ18O in cellulose and climate data. Finally, we test our results via 1-D hydrologic modeling of precipitation infiltration and water table rise and fall. These steps enable us to interpret hydrologic cycle variability within the 'critical zone' and their potential impact on riparian trees.

  14. 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.

  15. Sediment retention in rangeland riparian buffers.

    PubMed

    Hook, Paul B

    2003-01-01

    Controlling nonpoint-source sediment pollution is a common goal of riparian management, but there is little quantitative information about factors affecting performance of rangeland riparian buffers. This study evaluated the influence of vegetation characteristics, buffer width, slope, and stubble height on sediment retention in a Montana foothills meadow. Three vegetation types (sedge wetland, rush transition, bunchgrass upland) were compared using twenty-six 6- x 2-m plots spanning 2 to 20% slopes. Plots were clipped moderately (10-15 cm stubble) or severely (2-5 cm stubble). Sediment (silt + fine sand) was added to simulated overland runoff 6, 2, or 1 m above the bottom of each plot. Runoff was sampled at 15-s to > 5-min intervals until sediment concentrations approached background levels. Sediment retention was affected strongly by buffer width and moderately by vegetation type and slope, but was not affected by stubble height. Mean sediment retention ranged from 63 to > 99% for different combinations of buffer width and vegetation type, with 94 to 99% retention in 6-m-wide buffers regardless of vegetation type or slope. Results suggest that rangeland riparian buffers should be at least 6 m wide, with dense vegetation, to be effective and reliable. Narrower widths, steep slopes, and sparse vegetation increase risk of sediment delivery to streams. Vegetation characteristics such as biomass, cover, or density are more appropriate than stubble height for judging capacity to remove sediment from overland runoff, though stubble height may indirectly indicate livestock impacts that can affect buffer performance. PMID:12809315

  16. 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. PMID:23128759

  17. 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.

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. Cattle use patterns of riparian pastures in northeastern Oregon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock use of riparian areas has been fraught with controversy, with some arguing that livestock should be excluded while others emphasize the benefits of controlled grazing. Our study was designed to 1) characterize the nature of cattle grazing in riparian pastures, 2) determine intensity and s...

  7. Patterns of sediment and phosphorus accumulation in a riparian buffer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers prevent sediment and phosphorus (P) from reaching streams, but their accumulation in buffers is seldom measured. This study's objectives were to determine accumulations of sediment and P in a multi-species riparian buffer, and characterize spatial-temporal patterns of P in soil wate...

  8. Assessing the impact of riparian processes on streambank erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water dynamics within a streambank and riparian vegetation greatly affect streambank erosion. The integrated computer models CONCEPTS and REMM, which were developed to simulate stream channel morphology and riparian ecosystem function, were previously used to study the effectiveness of woody a...

  9. 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...

  10. RIPARIAN PLANT COMMUNITY PATTERNS: A CASE STUDY FROM SOUTHEASTERN ARIZONA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is concern about the preservation and, when necessary, restoration of riparian areas in semiarid regions. Understanding patterns of plant species composition and distribution within riparian corridors is helpful in planning for the management and protection of buffer strips that reduce the de...

  11. NITROUS OXIDE EMISSIONS FROM RIPARIAN BUFFERS AND TREATMENT WETLANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers and treatment wetlands are used throughout the world for the protection of water bodies from nonpoint source pollution, particularly nitrogen. Yet, relatively few studies of riparian or treatment wetland denitrification consider the production of nitrous oxide. Nitrous oxide emissio...

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. Climate and local geomorphic interactions drive patterns of riparian forest decline along a Mediterranean Basin river

    NASA Astrophysics Data System (ADS)

    Stella, John C.; Riddle, Jess; Piégay, Hervé; Gagnage, Matthieu; Trémélo, Marie-Laure

    2013-11-01

    Dynamic fluvial processes strongly influence ecological communities and ecosystem health in riverine and riparian ecosystems, particularly in drought-prone regions. In these systems, there is a need to develop tools to measure impacts from local and regional hydrogeomorphic changes on the key biological and physical processes that sustain riparian ecosystem health and potential recovery. We used dendrochronology of Populus nigra, a riparian tree that is vulnerable to changes in local hydrology, to analyze ecosystem response following channel incision due to gravel mining along the Drôme River, a Mediterranean Basin stream in southern France. We cored 55 trees at seven floodplain sites, measured ring widths, and calculated basal area growth to compare the severity and timing of local growth decline along the river. Current basal area increment (BAI) growth per tree ranged almost 10-fold among sites (7.7 ± 1.3 to 63.9 ± 15.2 cm2 year- 1, mean ± SE) and these differences were significant. Mean BAI was correlated positively with the proportion of healthy trees at a site, and negatively with proportion of dead canopy area. Regime shift analysis of the tree-ring series indicates that tree growth declined significantly at four sites since 1978, coincident with documented channel incision. In addition, patterns of low growth and crown dieback are consistent with stress due to reduced water supply. The most impaired sites were not directly adjacent to local mining pits visible on aerial photographs, nor did the sequence of growth regime shifts suggest a pattern of channel incision progressing from these areas. The initiation of site growth declines was most typically associated with drought years, and the most impaired sites were spatially distributed to suggest the influence of local bedrock controls on soil depth. Climate in the Drôme basin and in the Mediterranean region is trending significantly toward hotter growing seasons with a decrease in summer river

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. Linking riparian dynamics and groundwater: an ecohydrologic approach to modeling groundwater and riparian vegetation.

    PubMed

    Baird, Kathryn J; Stromberg, Juliet C; Maddock, Thomas

    2005-10-01

    The growing use of global freshwater supplies is increasing the need for improved modeling of the linkage between groundwater and riparian vegetation. Traditional groundwater models such as MODFLOW have been used to predict changes in regional groundwater levels, and thus riparian vegetation potential attributable to anthropogenic water use. This article describes an approach that improves on these modeling techniques through several innovations. First, evapotranspiration from riparian/wetland systems is modeled in a manner that more realistically reflects plant ecophysiology and vegetation complexity. In the authors' model programs (RIP-ET and PRE-RIP-ET), the single, monotonically increasing evapotranspiration flux curve in traditional groundwater models is replaced with a set of ecophysiologically based curves, one for each plant functional group present. For each group, the curve simulates transpiration declines that occur both as water levels decline below rooting depths and as waters rise to levels that produce anoxic soil conditions. Accuracy is further improved by more effective spatial handling of vegetation distribution, which allows modeling of surface elevation and depth to water for multiple vegetation types within each large model cell. The use of RIP-ET in groundwater models can improve the accuracy of basin scale estimates of riparian evapotranspiration rates, riparian vegetation water requirements, and water budgets. Two case studies are used to demonstrate that RIP-ET produces significantly different evapotranspiration estimates than the traditional method. When combined with vegetation mapping and a supporting program (RIP-GIS), RIP-ET also enables predictions of riparian vegetation response to water use and development scenarios. The RIP-GIS program links the head distribution from MODFLOW with surface digital elevation models, producing moderate- to high-resolution depth-to-groundwater maps. Together with information on plant rooting depths

  3. 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:

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Hydrologic dynamics and geochemical responses within a floodplain aquifer and hyporheic zone during Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Sawyer, A. H.; Kaplan, L. A.; Lazareva, O.; Michael, H. A.

    2014-06-01

    Storms dominate solute export budgets from catchments and drive hydrogeochemical changes in the near-stream environment. We captured near-stream hydrogeochemical dynamics during an intense storm (Hurricane Sandy, October 2012), by instrumenting a riparian-hyporheic zone transect of White Clay Creek in the Christina River Basin Critical Zone Observatory with pressure transducers, redox probes, and pore water samplers. In the floodplain aquifer, preferential vertical flow paths such as macropores facilitated rapid infiltration early in the storm. Water table rose quickly and promoted continuous groundwater discharge to the stream. Floodplain-hillslope topography controlled poststorm aquifer drainage rates, as the broad, western floodplain aquifer drained more slowly than the narrow, eastern floodplain aquifer adjacent to a steep hillslope. These changes in groundwater flow drove heterogeneous geochemical responses in the floodplain aquifer and hyporheic zone. Vertical infiltration in the floodplain and hyporheic exchange in the streambed increased DOC and oxygen delivery to microbially active sediments, which may have enhanced respiration. Resulting geochemical perturbations persisted from days to weeks after the storm. Our observations suggest that groundwater-borne solute delivery to streams during storms depends on unique interactions of vertical infiltration along preferential pathways, perturbations to groundwater geochemistry, and topographically controlled drainage rates.

  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. 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.

  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. 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.

  14. 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 trout. PMID:21688160

  15. Species replacement by a nonnative salmonid alters ecosystem function by reducing prey subsidies that support riparian spiders

    USGS Publications Warehouse

    Benjamin, J.R.; Fausch, K.D.; Baxter, C.V.

    2011-01-01

    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 trout. ?? 2011 Springer-Verlag.

  16. Improved Mapping of Riparian Wetlands Using Reach Topography (ECOSERV)

    EPA Science Inventory

    Riparian wetlands provide a suite of ecosystems services including floodwater retention, biogeochemical processing, and habitat provisioning. However in one mid-Atlantic watershed the National Wetlands Inventory was shown to underrepresent these systems by greater than 50%. These...

  17. Improved Mapping of Riparian Wetlands Using Reach Topography

    EPA Science Inventory

    Riparian wetlands provide a suite of ecosystems services including floodwater retention, biogeochemical processing, and habitat provisioning. However in one mid-Atlantic watershed the National Wetlands Inventory was shown to underrepresent these systems by greater than 50%. These...

  18. Incorporating climate change projections into riparian restoration planning and design

    USGS Publications Warehouse

    Perry, Laura G.; Lindsay V. Reynolds; Beechie, Timothy J.; Collins, Mathias J.; Shafroth, Patrick B.

    2015-01-01

    Climate change and associated changes in streamflow may alter riparian habitats substantially in coming decades. Riparian restoration provides opportunities to respond proactively to projected climate change effects, increase riparian ecosystem resilience to climate change, and simultaneously address effects of both climate change and other human disturbances. However, climate change may alter which restoration methods are most effective and which restoration goals can be achieved. Incorporating climate change into riparian restoration planning and design is critical to long-term restoration of desired community composition and ecosystem services. In this review, we discuss and provide examples of how climate change might be incorporated into restoration planning at the key stages of assessing the project context, establishing restoration goals and design criteria, evaluating design alternatives, and monitoring restoration outcomes. Restoration planners have access to numerous tools to predict future climate, streamflow, and riparian ecology at restoration sites. Planners can use those predictions to assess which species or ecosystem services will be most vulnerable under future conditions, and which sites will be most suitable for restoration. To accommodate future climate and streamflow change, planners may need to adjust methods for planting, invasive species control, channel and floodplain reconstruction, and water management. Given the considerable uncertainty in future climate and streamflow projections, riparian ecological responses, and effects on restoration outcomes, planners will need to consider multiple potential future scenarios, implement a variety of restoration methods, design projects with flexibility to adjust to future conditions, and plan to respond adaptively to unexpected change.

  19. Leaf litter dynamics and nitrous oxide emission in a Mediterranean riparian forest: implications for soil nitrogen dynamics.

    PubMed

    Bernal, S; Butturini, A; Nin, E; Sabater, F; Sabater, S

    2003-01-01

    Mediterranean riparian zones can experience severe drought periods that lead to low soil moisture content, which dramatically affects their performance as nitrate removal systems. In the Mediterranean riparian zone of this study, we determined that N2O emission was practically nil. To understand the role of forest floor processes in nitrogen retention of a Mediterranean riparian area, we studied leaf litter dynamics of two tree species, London planetree [Platanus x acerifolia (Aiton) Willd.] and alder [Alnus glutinosa (L.) Gaertn.], for two years, along with soil nitrogen mineralization rates. Annual leaf litter fall equaled 562.6 +/- 10.1 (standard error) g dry wt. m(-2), 68% of which was planetree and 32% of which was alder. The temporal distribution of litterfall showed a two-peak annual cycle, one occurring in midsummer, the other in autumn. Planetree provided the major input of organic nitrogen to the forest floor, and the amount of planetree leaves remaining on the forest floor was equivalent to approximately four years of stock. Leaf litter decomposition was three times higher for alder (decay coefficient [k] = 1.13 yr(-1)) than for planetree (k = 0.365 yr(-1)). Mineralization rates showed a seasonal pattern, with the maximum rate in summer (1.92 mg N kg(-1) d(-1)). Although the forest floor was an important sink for nitrogen due to planetree leaf accumulation, 7.5% of this leaf litter was scoured to the streambed by wind. This loss was irrelevant for alder leaves. Due to the litter quality, the forest floor of this Mediterranean riparian forest acts as a nitrogen sink. PMID:12549558

  20. 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

  1. From Sewers to Salix and Tailpipes to Typha: Riparian Plants Reflect Anthropogenic Nitrogen Sources Across Montane to Urban Gradients

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Hale, R. L.; Baker, M. A.; Bowling, D. R.; Ehleringer, J. R.

    2014-12-01

    Urban and suburban streams typically receive anthropogenic nitrogen (N) from multiple sources, and their identification and partitioning is a prerequisite for effective water quality management. However, stream N fluxes and sources are often highly variable, limiting the utility of water samples for source identification. Nitrate in perennial streams can provide an important N source for riparian vegetation in semi-arid environments. Thus, riparian plant tissue may integrate the stable isotope composition (δ15N) of stream nitrate over longer timescales and assist in source identification. Here, we tested whether δ15N of riparian plant leaves could provide an effective indicator of spatial variation in N sources across land use gradients spanning wildland to urban ecosystems in Salt Lake City, Utah, and the surrounding Wasatch Range Megapolitan Area. We found that leaf δ15N varied systematically within and among eight streams and rivers (n = 378 leaf samples) consistent with spatial land use variations. Plants from a suburban stream adjacent to homes with septic systems (δ15N = 5.1‰) were highly enriched relative to similar species from an adjacent undeveloped stream (δ15N = -0.7 ‰), suggesting an important contribution of enriched human fecal N to the suburban stream. Plants from a montane stream in a largely undeveloped recreational canyon that permitted off-leash dogs (δ15N = 1.8 ‰) were enriched relative to an adjacent canyon with similar land use that strictly prohibited dogs but had comparable vehicle traffic (δ15N = -0.7 ‰), suggesting the contribution of dog waste to stream N. Plants from urban stream reaches were enriched by 1.3 - 2.8 ‰ relative to upstream wildland reaches, and δ15N increased by 0.2 ‰ per km in the urban streams. Mechanisms leading to this urban enrichment could include leaky municipal sewers, atmospheric N deposition, and/or increased rates of N cycling and gaseous losses. Overall, our results demonstrate the potential

  2. Nitrogen dynamics among cropland and riparian buffers: soil-landscape influences.

    PubMed

    Young, Eric O; Briggs, Russell D

    2007-01-01

    Nitrate (NO3-) leaching to ground water poses water quality concerns in some settings. Riparian buffers have been advocated to reduce excess ground water NO3- concentrations. We characterized inorganic N in soil solution and shallow ground water for 16 paired cropland-riparian plots from 2003 to 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loam soils (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that cropland N inputs and soil-landscape variability would jointly affect NO3- leaching and transformations in ground water. Results showed that well and moderately well drained fields had consistently higher ground water NO3- compared to more imperfectly drained fields receiving comparable N inputs. Average 50-cm depth soil solution NO3- and ground water dissolved oxygen (DO) explained 64% of average cropland ground water NO3- variability. Cropland ground water with an average DO of <3 mg L(-1) tended to have <4 mg L(-1) of NO3- with a water table depth (WTD) of riparian zones. PMID:17485712

  3. Integrated assessment of groundwater - surface water exchange in the hillslope - riparian interface of a montane catchment

    NASA Astrophysics Data System (ADS)

    Scheliga, Bernhard; Tetzlaff, Doerthe; Nuetzmann, Gunnar; Soulsby, Chris

    2016-04-01

    Groundwater-surface water dynamics play an important role in runoff generation and the hydrologic connectivity between hillslopes and streams. Here, we present findings from a suite of integrated, empirical approaches to increase our understanding of groundwater-surface water interlinkages in a 3.2 km ^ 2 experimental catchment in the Scottish Highlands. The montane catchment is mainly underlain by granite and has extensive (70%) cover of glacial drift deposits which are up to 40 m deep and form the main aquifer in the catchment. Flat valley bottom areas fringe the stream channel and are characterised by peaty soils (0.5-4 m deep) which cover about 10% of the catchment and receive drainage from upslope areas. The transition between the hillslopes and riparian zone forms a critical interface for groundwater-surface water interactions that controls both the dynamics of riparian saturation and stream flow generation. We nested observations using wells to assess the groundwater - surface water transition, LiDAR surveys to explore the influence of micro-topography on shallow groundwater efflux and riparian wells to examine the magnitude and flux rates of deeper groundwater sources. We also used electrical resistivity surveys to assess the architecture and storage properties of drift aquifers. Finally, we used isotopic tracers to differentiate recharge sources and associated residence times as well as quantifying how groundwater dynamics affect stream flow. These new data have provided a novel conceptual framework for local groundwater - surface water exchange that is informing the development of new deterministic models for the site.

  4. Phosphorus reductions following riparian restoration in two agricultural watersheds in Vermont, USA.

    PubMed

    Meals, D W; Hopkins, R B

    2002-01-01

    Achievement of management goals for Lake Champlain (Vermont/New York, USA and Quebec, Canada) will require significant reductions of phosphorus (P) loads from agriculture, the dominant diffuse source in the basin. Cost-effective P reduction strategies must be based on reliable treatment techniques beyond basic erosion control and animal waste storage practices. The Lake Champlain Basin Agricultural Watersheds National Monitoring Program (NMP) Project evaluates the effectiveness of low-cost livestock exclusion, streambank protection, and riparian restoration practices in reducing concentrations and loads of diffuse-source pollutants from grazing land at the watershed level. Treatment and control watersheds in northwestern Vermont have been monitored since 1994 according to a paired-watershed design. Monitoring includes continuous stream discharge recording, flow-proportional sampling for total P and other pollutants, and documentation of land use and agricultural management activities. Strong statistical calibration between the control and treatment watersheds has been achieved. Landowner participation in the land treatment program was entirely voluntary and all treatments were 100% cost-shared by the project and cooperators. Installation of riparian fencing, alternative water supplies, protected stream crossings, and streambank bioengineering was completed in 1997 at a cost of less than US$40,000. The paired-watershed design was effective in controlling for the influence of extreme variations in precipitation and streamflow over six years of monitoring. Two years of post-treatment data have documented significant reductions in P concentrations and loads from both treated watersheds. Reductions of approximately 20% in mean total P concentration and approximately 20-50% in mean total P load have been observed, with greater reductions occurring in the watershed receiving more extensive treatment. The effectiveness of riparian zone restoration in P reduction tended to

  5. Trophic overlap between fish and riparian spiders: potential impacts of an invasive fish on terrestrial consumers.

    PubMed

    Jackson, Michelle C; Woodford, Darragh J; Bellingan, Terence A; Weyl, Olaf L F; Potgieter, Michael J; Rivers-Moore, Nick A; Ellender, Bruce R; Fourie, Hermina E; Chimimba, Christian T

    2016-03-01

    Studies on resource sharing and partitioning generally consider species that occur in the same habitat. However, subsidies between linked habitats, such as streams and riparian zones, create potential for competition between populations which never directly interact. Evidence suggests that the abundance of riparian consumers declines after fish invasion and a subsequent increase in resource sharing of emerging insects. However, diet overlap has not been investigated. Here, we examine the trophic niche of native fish, invasive fish, and native spiders in South Africa using stable isotope analysis. We compared spider abundance and diet at upstream fishless and downstream fish sites and quantified niche overlap with invasive and native fish. Spider abundance was consistently higher at upstream fishless sites compared with paired downstream fish sites, suggesting that the fish reduced aquatic resource availability to riparian consumers. Spiders incorporated more aquatic than terrestrial insects in their diet, with aquatic insects accounting for 45-90% of spider mass. In three of four invaded trout rivers, we found that the average proportion of aquatic resources in web-building spider diet was higher at fishless sites compared to fish sites. The probability of web-building and ground spiders overlapping into the trophic niche of invasive brown and rainbow trout was as high as 26 and 51%, respectively. In contrast, the probability of spiders overlapping into the trophic niche of native fish was always less than 5%. Our results suggest that spiders share resources with invasive fish. In contrast, spiders had a low probability of trophic overlap with native fish indicating that the traits of invaders may be important in determining their influence on ecosystem subsidies. We have added to the growing body of evidence that invaders can have cross-ecosystem impacts and demonstrated that this can be due to niche overlap. PMID:27087934

  6. Riparian influences on stream fish assemblage structure in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, B.J.; Freeman, Mary C.

    2007-01-01

    We assessed the influence of land cover at multiple spatial extents on fish assemblage integrity, and the degree to which riparian forests can mitigate the negative effects of catchment urbanization on stream fish assemblages. Riparian cover (urban, forest, and agriculture) was determined within 30 m buffers at longitudinal distances of 200 m, 1 km, and the entire network upstream of 59 non-nested fish sampling locations. Catchment and riparian land cover within the upstream network were highly correlated, so we were unable to distinguish between those variables. Most fish assemblage variables were related to % forest and % urban land cover, with the strongest relations at the largest spatial extent of land cover (catchment), followed by riparian land cover in the 1-km and 200-m reach, respectively. For fish variables related to urban land cover in the catchment, we asked whether the influence of riparian land cover on fish assemblages was dependent on the amount of urban development in the catchment. Several fish assemblage metrics (endemic richness, endemic:cosmopolitan abundance, insectivorous cyprinid richness and abundance, and fluvial specialist richness) were all best predicted by single variable models with % urban land cover. However, endemic:cosmopolitan richness, cosmopolitan abundance, and lentic tolerant abundance were related to % forest cover in the 1-km stream reach, but only in streams that had <15% catchment urban land cover. In these cases, catchment urbanization overwhelmed the potential mitigating effects of riparian forests on stream fishes. Together, these results suggest that catchment land cover is an important driver of fish assemblages in urbanizing catchments, and riparian forests are important but not sufficient for protecting stream ecosystems from the impacts of high levels of urbanization.

  7. Remote sensing of the impact of a large dam on the riparian vegetation canopy

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Kellogg, C.

    2013-12-01

    To tap the water resources and hydropower from large rivers, numerous large dams have been built in the world. How the construction of such dams impacts the riparian vegetation ecosystem along the river at which the dams have been built is still an open question. In this study we use the Three Gorges dam on the Yangtze River in China as a case to study the impact of the fluctuation of water levels of the reservoir due to the dam along the river (see Figure 1). Our hypothesis is that the impact of the dam construction on riparian plant ecosystem should be elevation-related. To test this, we divide the riparian area along the river into a certain zones according to elevation. Based on the remotely sensed Normalized Difference Vegetation Index (NDVI) of Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra satellite, we derived the Fraction of Absorbed Photosynthetically Active Radiation (FPAR). Remotely sensed NDVI, Enhanced Vegetation Index (EVI), and the derived FPAR data sources represent the vigor and health status of vegetation canopy and vegetation cover. The status of vegetation cover is categorized into three categories according to NDVI, EVI, or FPAR. For instance, the three categories according to NDVI are: non-vegetated (NDVI < 0.3), sparsely vegetated (0.3 < NDVI < 0.6), and densely vegetated (NDVI > 0.6). Area of each category within each elevation zone was derived from the vegetation indices or FPAR data and the overlapping digital elevation model (DEM) data from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The time evolution of the area of each category within each elevation zone can thus be tracked down and regression analyzed with the water level data. Results show that over the decade-long water-storing period (2000-2010), non-vegetated land cover increased in the inundated zone (elevation below 175m); dense vegetation land cover increased within the elevation zone of 175m-775m and no change in

  8. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  9. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  10. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  11. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  12. Demographic histories of adaptively diverged riparian and non-riparian species of Ainsliaea (Asteraceae) inferred from coalescent analyses using multiple nuclear loci

    PubMed Central

    2012-01-01

    Background Understanding demographic histories, such as divergence time, patterns of gene flow, and population size changes, in ecologically diverging lineages provide implications for the process and maintenance of population differentiation by ecological adaptation. This study addressed the demographic histories in two independently derived lineages of flood-resistant riparian plants and their non-riparian relatives [Ainsliaea linearis (riparian) and A. apiculata (non-riparian); A. oblonga (riparian) and A. macroclinidioides (non-riparian); Asteraceae] using an isolation-with-migration (IM) model based on variation at 10 nuclear DNA loci. Results The highest posterior probabilities of the divergence time parameters were estimated to be ca. 25,000 years ago for A. linearis and A. apiculata and ca. 9000 years ago for A. oblonga and A. macroclinidioides, although the confidence intervals of the parameters had broad ranges. The likelihood ratio tests detected evidence of historical gene flow between both riparian/non-riparian species pairs. The riparian populations showed lower levels of genetic diversity and a significant reduction in effective population sizes compared to the non-riparian populations and their ancestral populations. Conclusions This study showed the recent origins of flood-resistant riparian plants, which are remarkable examples of plant ecological adaptation. The recent divergence and genetic signatures of historical gene flow among riparian/non-riparian species implied that they underwent morphological and ecological differentiation within short evolutionary timescales and have maintained their species boundaries in the face of gene flow. Comparative analyses of adaptive divergence in two sets of riparian/non-riparian lineages suggested that strong natural selection by flooding had frequently reduced the genetic diversity and size of riparian populations through genetic drift, possibly leading to fixation of adaptive traits in riparian

  13. Prescribed grazing as a secondary impact in a western riparian floodplain

    USGS Publications Warehouse

    Sedgwick, J.A.; Knopf, F.L.

    1991-01-01

    The effect of late-autumn cattle grazing on plant biomass was examined in a western Great Plains cottonwood riparian zone prone to catastrophic flooding every 5-8 years. Following 1 year of pre-treatment data collection in 1982, five 16-ha pastures were grazed from 1982 to 1984 and compared to 5 control pastures within the South Platte River floodplain in northeastern Colorado. At a prescribed grazing level of 0.46 ha/AUM, riparian vegetation proved to be resilient to the impacts of grazing. We detected only a few significant treatment effects for above-ground biomass after succeeding growing seasons. Willows (Salix spp.) responded negatively to grazing whereas biomass of prairie cordgrass (Spartina pectinata Link) was greater on grazed plots. Yearly changes in above-ground biomass, especially dramatic following a severe flood in 1983, suggest that periodic, catastrophic flooding is a major perturbation to the ecosystem, and in conjunction with our results on grazing impacts, indicate that dormant-season grazing within Soil Conservation Service (SCS) guidelines is a comparatively minor impact within the floodplain. In addition, grazing impacts were probably further mitigated by a major forage supplement of cottonwood leaves which was available at the time of cattle introductions. This local forage supplement ultimately created a lighter grazing treatment than that originally prescribed.

  14. Low thermal tolerances of stream amphibians in the Pacific Northwest: Implications for riparian and forest management

    USGS Publications Warehouse

    Bury, R.B.

    2008-01-01

    Temperature has a profound effect on survival and ecology of amphibians. In the Pacific Northwest, timber harvest is known to increase peak stream temperatures to 24??C or higher, which has potential to negatively impact cold-water stream amphibians. I determined the Critical Thermal Maxima (CT max) for two salamanders that are endemic to the Pacific Northwest. Rhyacotriton variegatus larvae acclimated at 10??C had mean CTmax of 26.7 ?? 0.7 SD??C and adults acclimated at 11??C had mean CT max of 27.9 ?? 1.1??C. These were among the lowest known values for any amphibian. Values were significantly higher for larval Dicamptodon tenebrosus acclimated at 14??C (x = 29.1 ?? 0.2??C). Although the smallest R. variegatus had some of the lowest values, size of larvae and adults did not influence CTmax in this species. Current forest practices retain riparian buffers along larger fish-bearing streams; however, such buffers along smaller headwaters and non-fish bearing streams may provide favorable habitat conditions for coldwater-associated species in the Pacific Northwest. The current study lends further evidence to the need for protection of Northwest stream amphibians from environmental perturbations. Forest guidelines that include riparian buffer zones and configurations of upland stands should be developed, while monitoring amphibian responses to determine their success. ?? 2008 Brill Academic Publishers.

  15. Spectral discrimination of giant reed (Arundo donax L.): A seasonal study in riparian areas

    NASA Astrophysics Data System (ADS)

    Fernandes, Maria Rosário; Aguiar, Francisca C.; Silva, João M. N.; Ferreira, Maria Teresa; Pereira, José M. C.

    2013-06-01

    The giant reed (Arundo donax L.) is amongst the one hundred worst invasive alien species of the world, and it is responsible for biodiversity loss and failure of ecosystem functions in riparian habitats. In this work, field spectroradiometry was used to assess the spectral separability of the giant reed from the adjacent vegetation and from the common reed, a native similar species. The study was conducted at different phenological periods and also for the giant reed stands regenerated after mechanical cutting (giant reed_RAC). A hierarchical procedure using Kruskal-Wallis test followed by Classification and Regression Trees (CART) was used to select the minimum number of optimal bands that discriminate the giant reed from the adjacent vegetation. A new approach was used to identify sets of wavelengths - wavezones - that maximize the spectral separability beyond the minimum number of optimal bands. Jeffries Matusita and Bhattacharya distance were used to evaluate the spectral separability using the minimum optimal bands and in three simulated satellite images, namely Landsat, IKONOS and SPOT. Giant reed was spectrally separable from the adjacent vegetation, both at the vegetative and the senescent period, exception made to the common reed at the vegetative period. The red edge region was repeatedly selected, although the visible region was also important to separate the giant reed from the herbaceous vegetation and the mid infrared region to the discrimination from the woody vegetation. The highest separability was obtained for the giant reed_RAC stands, due to its highly homogeneous, dense and dark-green stands. Results are discussed by relating the phenological, morphological and structural features of the giant reed stands and the adjacent vegetation with their optical traits. Weaknesses and strengths of the giant reed spectral discrimination are highlighted and implications of imagery selection for mapping purposes are argued based on present results.

  16. 78 FR 7265 - Security Zone; Protection of Military Cargo, Captain of the Port Zone Puget Sound, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ... assets and military cargo in the navigable waters of Puget Sound to and adjacent waters. (See 69 FR 52600... SECURITY Coast Guard 33 CFR Part 165 Security Zone; Protection of Military Cargo, Captain of the Port Zone... military cargo in the navigable waters of Puget Sound and adjacent waters. Entry into this zone...

  17. Water use sources of desert riparian Populus euphratica forests.

    PubMed

    Si, Jianhua; Feng, Qi; Cao, Shengkui; Yu, Tengfei; Zhao, Chunyan

    2014-09-01

    Desert riparian forests are the main body of natural oases in the lower reaches of inland rivers; its growth and distribution are closely related to water use sources. However, how does the desert riparian forest obtains a stable water source and which water sources it uses to effectively avoid or overcome water stress to survive? This paper describes an analysis of the water sources, using the stable oxygen isotope technique and the linear mixed model of the isotopic values and of desert riparian Populus euphratica forests growing at sites with different groundwater depths and conditions. The results showed that the main water source of Populus euphratica changes from water in a single soil layer or groundwater to deep subsoil water and groundwater as the depth of groundwater increases. This appears to be an adaptive selection to arid and water-deficient conditions and is a primary reason for the long-term survival of P. euphratica in the desert riparian forest of an extremely arid region. Water contributions from the various soil layers and from groundwater differed and the desert riparian P. euphratica forests in different habitats had dissimilar water use strategies. PMID:24816539

  18. Gilliam County Riparian Buffers; 2003-2004 Annual Reports.

    SciTech Connect

    Coiner, Josh

    2004-06-01

    Interest appears to be at an all-time high for riparian conservation programs in Gilliam County. With the recently added Herbaceous Buffer and the already established CREP program interest is booming. However, more and more people are turning towards the herbaceous buffer because of expense. The riparian forest buffer is becoming too expensive. Even with the excellent cost share and incentives landowners are having trouble with Farm Service Agency's payment limitation. Because of this payment limitation landowners are not receiving their full rental and incentive payments, usually in year one. This has cooled the installation of riparian forest buffers and peaked interest in the CP-29 (Herbaceous Buffer for Wildlife). Either way, riparian lands are being enhanced and water quality is being improved. Year three should be very similar to the accomplishments of year 2. There has already been several projects proposed that may or may not be approved during year 3. I am currently working on three projects that are all over 2.5 miles long on each side and total anywhere from 60 to 250 acres in size. Along with these three projects there at least seven small projects being proposed. Four of those projects are riparian forest buffers and the remaining are herbaceous buffers.

  19. Links between riparian landcover, instream environment and fish assemblages in headwater streams of south-eastern Brazil

    USGS Publications Warehouse

    Cruz, Bruna B.; Miranda, Leandro E.; Cetra, Mauricio

    2013-01-01

    We hypothesised and tested a hierarchical organisation model where riparian landcover would influence bank composition and light availability, which in turn would influence instream environments and control fish assemblages. The study was conducted during the dry season in 11 headwater tributaries of the Sorocaba River in the upper Paraná River Basin, south-eastern Brazil. We focused on seven environmental factors each represented by one or multiple environmental variables and seven fish functional traits each represented by two or more classes. Multivariate direct gradient analyses suggested that riparian zone landcover can be considered a higher level causal factor in a network of relations that control instream characteristics and fish assemblages. Our results provide a framework for a hierarchical conceptual model that identifies singular and collective influences of variables from different scales on each other and ultimately on different aspects related to stream fish functional composition. This conceptual model is focused on the relationships between riparian landcover and instream variables as causal factors on the organisation of stream fish assemblages. Our results can also be viewed as a model for headwater stream management in that landcover can be manipulated to influence factors such as bank composition, substrates and water quality, whereas fish assemblage composition can be used as indicators to monitor the success of such efforts.

  20. Riparian vegetation patterns in relation to fluvial landforms and channel evolution along selected rivers of Tuscany (Central Italy)

    USGS Publications Warehouse

    Hupp, C.R.; Rinaldi, M.

    2007-01-01

    Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, landforms, and processes are described and interpreted for selected rivers of Tuscany, Central Italy; with emphasis on channel evolution following human impacts. Field surveys were conducted along thirteen gauged reaches for species presence, fluvial landforms, and the type and amount of channel/riparian zone change. Inundation frequency of different geomorphic surfaces was determined, and vegetation data were analyzed using BDA (binary discriminate analysis) and DCA (detrended correspondence analysis) and related to hydrogeomorphology. Multivariate analyses revealed distinct quantitative vegetation patterns relative to six major fluvial geomorphic surfaces. DCA of the vegetation data also showed distinct associations of plants to processes of adjustment that are related to stage of channel evolution, and clearly separated plants along disturbance/landform/soil moisture gradients. Species richness increases from the channel bed to the terrace and on heterogeneous riparian areas, whereas species richness decreases from moderate to intense incision and from low to intense narrowing. ?? 2007 by Association of American Geographers.

  1. PREDICTIONS OF STREAM WOOD RECRUITMENT FROM RIPARIAN FORESTS: EFFECTS OF DATA RESOLUTION

    EPA Science Inventory

    We evaluate whether different levels of detail of riparian forest characterizations result in different predictions of stream wood recruitment from riparian forests in northwestern Oregon. If less detailed information provides the same estimate of this function as more detailed i...

  2. RELATIONSHIPS AMONG GEOMORPHOLOGY, HYDROLOGY, AND VEGETATION IN RIPARIAN MEADOWS: RESTORATION IMPLICATIONS

    EPA Science Inventory

    Vegetation patterns and dynamics within riparian corridors are controlled largely by geomorphic position, substrate characteristics and hydrologic regimes. Understanding management and restoration options for riparian meadow complexes exhibiting stream incision requires knowledge...

  3. The dark side of suibsidies: quantifying contaminant exposure to riparian predators via stream insects

    EPA Science Inventory

    Aquatic insects provide a critical nutrient subsidy to riparian food webs, yet their role as vectors of contaminants to terrestrial ecosystems is poorly understood. We investigated relationships between aquatic (resource utilization) and contaminant exposure for a riparian invert...

  4. Linking Changes in Management and Riparian Physical Functionality to Water Quality and Aquatic Habitat

    EPA Science Inventory

    Wildlife and aquatic habitats are dependent on the development of riparian area management strategies. Land management strategies consider certain basic ecological and economic relationships. These relationships are functions of riparian and te rrestrial ecosystems, which include...

  5. Vegetation development following stream/river restoration: more natural fluvial dynamics and morphology, return of aquatic and riparian plant species?

    NASA Astrophysics Data System (ADS)

    Soons, M. B.

    2012-04-01

    , even if seeds have successfully dispersed into an area, local germination and establishment may also be limiting for the development of local biodiversity and/or for restoration success. However, we know surprisingly little about the crucial process of colonization. This presentation focusses on colonization by aquatic and riparian plant species. I combine the results of several studies investigating dispersal, germination and establishment. A study on restored riparian zones along mountain streams shows that several years after restoration, the species composition at the restored sites shows signs of dispersal limitation: species with nearby source populations re-colonized successfully, but species without source populations in the immediate surroundings often remained absent. A detailed study on the re-colonization of a restored riparian zone along a lowland stream reveals that many species enter the site as seeds, but relatively few of these seeds are able to germinate and establish successfully, indicating that both a strong dispersal filter and a strong environmental filter control local vegetation development and hence stream dynamics and morphological developments. While the intensity of the disturbance of local conditions has a great impact on the role of the environmental filter, dispersal clearly remains a limiting factor in many situations.

  6. Estimating Effective Stream Shade in Riparian Areas

    NASA Astrophysics Data System (ADS)

    Sydow, L.; Link, T. E.; Gravelle, J. A.

    2009-12-01

    Concern about the effects of land cover change on stream temperature dynamics necessitates the quantification of effective stream shade for riparian management and water quality modeling. Accurate quantification of stream shade with radiometers is both challenging and expensive over large areas characterized by complex and spatially variable canopies. To address these challenges, a number of shade estimation methods have been developed for rapid stream cover assessments. The main objective of this study was to determine which of four canopy cover estimation methods best characterized effective shade in harvested and unharvested stream reaches. An associated objective was to understand how canopy cover and type affected the accuracy of the methods. The four methods tested were a manual canopy densiometer, analysis of standard imagery from a digital camera, the Solar Pathfinder, and analysis of hemispherical imagery using Hemiview software. These were compared to measurements of percent incoming shortwave radiation quantified with Hukseflux NR-01 radiometers at each location. Four stream reaches in the Mica Creek Experimental Watershed were used to assess the estimation methods under different amounts and types of canopy cover: an unharvested area, a partial cut, an open clear cut, and a clear cut with dense understory. All estimation methods were most accurate in the most shaded location (dense understory clear cut) and least accurate in the open clear cut, the least shaded location. The values estimated by Hemiview proved to be the most accurate in all four areas, differing from the true value by ~5% on average; the Solar Pathfinder was the second most accurate with an error of ~8%. The results from the digital camera and canopy densiometer were comparable, at ~15% difference from the true value. While Hemiview is the most expensive and time consuming of the four methods, it was the most accurate for estimating effective stream shade in this study.

  7. Rivers through time: historical changes in the riparian vegetation of the semi-arid, winter rainfall region of South Africa in response to climate and land use.

    PubMed

    Hoffman, M Timm; Rohde, Richard Frederick

    2011-01-01

    This paper examines how the riparian vegetation of perennial and ephemeral rivers systems in the semi-arid, winter rainfall region of South Africa has changed over time. Using an environmental history approach we assess the extent of change in plant cover at 32 sites using repeat photographs that cover a time span of 36-113 years. The results indicate that in the majority of sites there has been a significant increase in cover of riparian vegetation in both the channel beds and adjacent floodplain environments. The most important species to have increased in cover across the region is Acacia karroo. We interpret the findings in the context of historical changes in climate and land use practices. Damage to riparian vegetation caused by mega-herbivores probably ceased sometime during the early 19th century as did scouring events related to large floods that occurred at regular intervals from the 15th to early 20th centuries. Extensive cutting of riparian vegetation for charcoal and firewood has also declined over the last 150 years. Changes in the grazing history as well as increased abstraction and dam building along perennial rivers in the region also account for some of the changes observed in riparian vegetation during the second half of the 20th century. Predictions of climate change related to global warming anticipate increased drought events with the subsequent loss of species and habitats in the study area. The evidence presented here suggests that an awareness of the region's historical ecology should be considered more carefully in the modelling and formulation of future climate change predictions as well as in the understanding of climate change impacts over time frames of decades and centuries. PMID:20665084

  8. The effect of macropores on bi-directional hydrologic exchange between a stream channel and riparian groundwater

    NASA Astrophysics Data System (ADS)

    Menichino, Garrett T.; Hester, Erich T.

    2015-10-01

    Macropores and soil pipes in stream banks are common geomorphic features. Macropores and soil pipes that are open to the channel (i.e. "bank face-connected" macropores) are inundated when channel stage is elevated (e.g., from precipitation, snowmelt, dam release). However, previous studies have not investigated macropore impact on bi-directional water exchange between the channel and bank/riparian groundwater under variable hydrologic conditions. We monitored two transects of riparian groundwater wells perpendicular to the bank of a 2nd order stream for a year: one with bank face-connected macropores (M transect) and one without bank face-connected macropores (NM transect). Fluctuations in water level and temperature during storms in those wells closest to the channel were on average 139% and 29% higher, respectively, in the presence of macropores. Rising head tests in the same wells indicated that hydraulic conductivity was 61-140 times higher in the presence of macropores. Bank storage, indicated by gradient reversals between channel and riparian zone, occurred on two temporal scales. Bank storage during storms was more frequent in the M transect (occurred all year) than in the NM transect (occurred just in winter and spring). Smaller magnitude gradient reversals at the M transect are consistent with faster head equilibration and greater exchange volume. Bank storage also occurred on an annual basis, with channel water entering storage during summer and fall and returning to the channel during winter and spring. Taken together, these results suggest that macropores act as preferential flow paths that enhance the connectivity between channels and riparian groundwater that influences bank storage. Where bank macropores are present, conceptual models of hyporheic and groundwater flow should account for their effects.

  9. Influence of rhizosphere microbial ecophysiological parameters from different plant species on butachlor degradation in a riparian soil.

    PubMed

    Yang, Changming; Wang, Mengmeng; Li, Jianhua

    2012-01-01

    Biogeochemical processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. However, little research has been reported on the microbial process and degradation potential of herbicide in a riparian soil. Field sampling and incubation experiments were conducted to investigate differences in microbial parameters and butachlor degradation in the riparian soil from four plant communities in Chongming Island, China. The results suggested that the rhizosphere soil had significantly higher total organic C and water-soluble organic C relative to the nonrhizosphere soil. Differences in rhizosphere microbial community size and physiological parameters among vegetation types were significant. The rhizosphere soil from the mixed community of Phragmites australis and Acorus calamus had the highest microbial biomass and biochemical activity, followed by A. calamus, P. australis and Zizania aquatica. Microbial ATP, dehydrogenase activity (DHA), and basal soil respiration (BSR) in the rhizosphere of the mixed community of P. australis and A. calamus were 58, 72, and 62% higher, respectively, than in the pure P. australis community. Compared with the rhizosphere soil of the pure plant communities, the mixed community of P. australis and A. calamus displayed a significantly greater degradation rate of butachlor in the rhizosphere soil. Residual butachlor concentrations in rhizosphere soil of the mixed community of P. australis and A. calamus and were 48, 63, and 68% lower than three pure plant communities, respectively. Butachlor degradation rates were positively correlated to microbial ATP, DHA, and BSR, indicating that these microbial parameters may be useful in assessing butachlor degradation potential in the riparian soil. PMID:22565253

  10. Microbial communities in riparian soils of a settling pond for mine drainage treatment.

    PubMed

    Fan, Miaochun; Lin, Yanbing; Huo, Haibo; Liu, Yang; Zhao, Liang; Wang, Entao; Chen, Weimin; Wei, Gehong

    2016-06-01

    Mine drainage leads to serious contamination of soil. To assess the effects of mine drainage on microbial communities in riparian soils, we used an Illumina MiSeq platform to explore the soil microbial composition and diversity along a settling pond used for mine drainage treatment. Non-metric multidimensional scaling analysis showed that the microbial communities differed significantly among the four sampling zones (influent, upstream, downstream and effluent), but not seasonally. Constrained analysis of principal coordinates indicated heavy metals (zinc, lead and copper), total sulphur, pH and available potassium significantly influenced the microbial community compositions. Heavy metals were the key determinants separating the influent zone from the other three zones. Lower diversity indices were observed in the influent zone. However, more potential indicator species, related to sulphur and organic matter metabolism were found there, such as the sulphur-oxidizing genera Acidiferrobacter, Thermithiobacillus, Limnobacter, Thioprofundum and Thiovirga, and the sulphur-reducing genera Desulfotomaculum and Desulfobulbus; the organic matter degrading genera, Porphyrobacter and Paucimonas, were also identified. The results indicated that more microorganisms related to sulphur- and carbon-cycles may exist in soils heavily contaminated by mine drainage. PMID:27055175

  11. Temporal Hyporheic Zone Response to Water Table Fluctuations.

    PubMed

    Malzone, Jonathan M; Anseeuw, Sierra K; Lowry, Christopher S; Allen-King, Richelle

    2016-03-01

    Expansion and contraction of the hyporheic zone due to temporal hydrologic changes between stream and riparian aquifer influence the biogeochemical cycling capacity of streams. Theoretical studies have quantified the control of groundwater discharge on the depth of the hyporheic zone; however, observations of temporal groundwater controls are limited. In this study, we develop the concept of groundwater-dominated differential hyporheic zone expansion to explain the temporal control of groundwater discharge on the hyporheic zone in a third-order stream reach flowing through glacially derived terrain typical of the Great Lakes region. We define groundwater-dominated differential expansion of the hyporheic zone as: differing rates and magnitudes of hyporheic zone expansion in response to seasonal vs. storm-related water table fluctuation. Specific conductance and vertical hydraulic gradient measurements were used to map changes in the hyporheic zone during seasonal water table decline and storm events. Planar and riffle beds were monitored in order to distinguish the cause of increasing hyporheic zone depth. Planar bed seasonal expansion of the hyporheic zone was of a greater magnitude and longer in duration (weeks to months) than storm event expansion (hours to days). In contrast, the hyporheic zone beneath the riffle bed exhibited minimal expansion in response to seasonal groundwater decline compared to storm related expansion. Results indicated that fluctuation in the riparian water table controlled seasonal expansion of the hyporheic zone along the planar bed. This groundwater induced hyporheic zone expansion could increase the potential for biogeochemical cycling and natural attenuation. PMID:26096382

  12. Effect of gender on sap-flux-scaled transpiration in a dominant riparian tree species: Box elder (Acer negundo)

    NASA Astrophysics Data System (ADS)

    Hultine, K. R.; Bush, S. E.; West, A. G.; Ehleringer, J. R.

    2007-09-01

    flux from dominant riparian vegetation adjacent to the stream channel. Results from this investigation show that the population structure of dioecious riparian trees has direct consequences on ecosystem ET, particularly along stream margins. Shifts in population structure therefore, may have profound impacts on several ecohydrological processes including stream discharge, biogeochemical cycling, and ecosystem productivity.

  13. Sediment Transport and Deposition in Tidal Riparian Wetlands During Drought Conditions

    NASA Astrophysics Data System (ADS)

    Renfro, A. A.; Leonard, L. A.; Croft, A. L.

    2004-12-01

    Rates of sediment deposition in coastal riparian wetland are determined, in part, by the amount of sediment available in the flooding waters. In the Lower Cape Fear River (LCFR) estuary in southeastern North Carolina total suspended solids (TSS) are received from three major tributaries: Cape Fear mainstem (CFR), Northeast Cape Fear (NECFR), and Black Rivers (BR). The sediment delivered to the estuary depends on the tributary characteristics and climatological conditions in the watersheds. In coastal North Carolina, two primary types of streams, brown-water and black-water, drain vastly different headwater areas and therefore contrast greatly in the amount of sediment they carry and can potentially deposit in adjacent swamps. TSS concentrations in the brown-water river (Cape Fear River) range from 5-35 mg L-1, but TSS are typically lower (<10 mg L$^{-1}) in the black-water streams. From spring 2000 to winter 2002 severe drought conditions were present, particularly in the piedmont region. Although streamflow was reduced during drought conditions, mean TSS concentrations were significantly higher during the drought than during normal conditions for both the CFR and NECFR. At a swamp adjacent to CFR total and inorganic suspended sediment concentrations decreased slightly, but not significantly over time during drought conditions, suggesting a loss of suspended sediment to the wetland surface. During normal conditions TSS and ISS concentrations increased slightly, but not significantly, suggesting inhibited settling or export. Sediment deposition data during the drought was consistent with the flux data indicating deposition did not differ significantly between normal and drought conditions. However, total and inorganic deposition was higher during the drought period. At a swamp adjacent to the NECFR suspended sediment concentrations did not vary relative to high tide for either normal or drought conditions. Sediment trap data indicated little difference in deposition

  14. Contrasting behaviour of two riparian wetlands in relation to their location in the hydrographic network

    NASA Astrophysics Data System (ADS)

    Montreuil, Olivier; Cudennec, Christophe; Merot, Philippe

    2011-08-01

    SummaryAlthough many studies have focused on the hydrological behaviour and classification of wetlands, the wide diversity of wetlands makes a clear and operational view difficult. The objective of this work is to compare the organisation and behaviour of two riparian wetlands (RWs) located, respectively, along Strahler order-2 and order-5 streams of the Scorff River catchment (Brittany, France). Groundwater table dynamics were monitored at the RWs during one hydrological year. Hydrochemistry was characterised during hydrological periods of high and low hydraulic head. The results show clearly the contrast in geomorphological and pedological organisation between the two RWs. In addition, the RW along an order-2 stream exhibited a strong hydrological connectivity with the adjacent hillslope whereas the RW along an order-5 stream showed a strong hydrological connectivity with the adjacent stream. We also observed the contrast between conditions favourable for high and permanent denitrification but on low nitrogen fluxes for order 2, and conditions less favourable to denitrification but on strong nitrogen fluxes for order 5. The relation between the contrasting hydrological and hydrochemical behaviour of these two RWs and their stream orders is discussed from the literature and local observations of the catchment. The results support the hypothesis of a relation between stream order and the hydrological and hydrochemical behaviour of the RWs and thus a catchment-scale organisation which may be taken into consideration in management strategies.

  15. Effects of Stream and Elevation Resolution on Riparian Metrics and Restoration Identification

    EPA Science Inventory

    Even though riparian areas attenuate nutrients and sediments from agricultural runoff at the field scale, best management practices and locations for restoring riparian areas should be determined at watershed scales. Riparian metrics (e.g., percent forest within 100m of stream)...

  16. Role of riparian areas in atmospheric pesticide deposition and its potential effect on water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are known to mitigate hydrologic losses of nutrients and other contaminants as they exit agricultural fields. The vegetation of riparian buffers can also trap atmospheric contaminants, but these pollutants can subsequently be delivered via rain to the riparian buffer floor. These ...

  17. Stream network expansion: a riparian water quality factor

    NASA Astrophysics Data System (ADS)

    Wigington, P. J., Jr.; Moser, T. J.; Lindeman, D. R.

    2005-05-01

    Little is known about how active stream network expansion during rainstorms influences the ability of riparian buffers to improve water quality. We used aerial photographs to quantify stream network expansion during the wet winter season in five agricultural catchments in western Oregon, USA. Winter stream drainage densities were nearly two orders of magnitude greater than summer stream densities, and agricultural land use was much more abundant along transient portions (e.g. swales, road ditches) of stream networks. Water moving from agricultural fields into expanded stream networks during large hydrologic events has the opportunity to bypass downstream riparian buffers along perennial streams and contribute nonpoint-source pollutants directly into perennial stream channels.

  18. Water Table Dynamics of a Rocky Mountain Riparian Area

    NASA Astrophysics Data System (ADS)

    Westbrook, C. J.

    2009-05-01

    Riparian areas in mountain valleys serve as collection points for local precipitation, hillslope runoff, deeper groundwater, and channel water. Little is known about how complex hydrological interactions among these water sources govern riparian water table dynamics, particularly on an event basis partly owing to a lack of high frequency spatial and temporal data. Herein I describe the magnitude and rate of change of groundwater storage in a 1.3 km2 Canadian Rocky Mountain peat riparian area. Weekly manual measurement of hydraulic heads in a network of 51 water table wells during the summers of 2006 and 2007 showed large temporal and spatial variations in well response. A near constant increase in the spatial heterogeneity of the water table was observed as the riparian area dried. Cluster analysis and principle components analysis were performed on these weekly data to objectively classify the riparian area into spatial response units. Results were classification of the standpipes into five distinct water table regimes. One well representing each water table regime was outfitted with a sensor in 2008 that measured hourly head, which was used to characterize temporal dynamics of water table response. In spring, snowmelt runoff combined with an ice lens 20-30 cm below the ground surface led to consistently high water tables throughout the riparian area. In summer, the water table fell throughout the riparian in response to declining hillslope inputs and increased evaporative demand, but rates of decline were highly variable among the water table regimes. Chloride concentrations suggest variability reflects differences in the degree to which the water table regimes are influenced by stream stage, hillslope inputs, and proximity to beaver dams. Water table regime responses to rain events were flashy, with dramatic rises and falls (up to 20 cm) in short periods of time (<30 h), suggesting the unsaturated soil was near saturation. The stream was considerably more

  19. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2005-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extent to which flow concentration affects buffer efficiency. Recommendations are presented for the design of adaptive-width buffers.

  20. Concentrated Flow through a Riparian Buffer: A Case Study

    NASA Astrophysics Data System (ADS)

    Young, C. B.; Nogues, J. P.; Hutchinson, S. L.

    2004-05-01

    Riparian buffers are often used for in-situ treatment of agricultural runoff. Although the benefits of riparian buffers are well recongized, concentration of flow can restrict the efficiency of contaminant removal. This study evaluates flow concentration at a agricultural site near Manhattan, Kansas. Manual and automated GIS analyses of a high-resolution digital elevation model were used to determine the fraction of runoff contributing to each buffer segment. Subsequent simulation of the system in WEPP (Water Erosion and Prediction Project) demonstrates the extend to which flow concentration affects buffer efficiency.

  1. Riparian-wetland initiative for the 1990`s

    SciTech Connect

    1990-09-01

    This Riparian-Wetland Initiative for the 1990`s provides a blueprint for management and restoration of those areas encompassing 23.7 million acres of BLM lands. This strategy complements other plans such as Waterfowl Habitat Management on Public Lands, A Strategy for the Future and other interdisciplinary, multi-program, cooeprative efforts. Four goals have been established: to restore and maintain riparian-wetland areas so that 75% or more are in proper functioning condition by 1997, to protect areas through proper land management to avoid or mitigate negative impacts, to ensure an aggressive information program, and to improve partnerships and cooperative restorative and management processes.

  2. A Long-term Reach-Scale Monitoring Network for Riparian Evapotranspiration, Rock Creek, Kansas

    NASA Astrophysics Data System (ADS)

    Rajaram, H.; Solis, J. A.; Whittemore, D. O.; Butler, J. J.; Reboulet, E.; Knobbe, S.; Dealy, M.

    2011-12-01

    Riparian evapotranspiration (RET) is an important component of basin-wide evapotranspiration (ET), especially in subhumid to semi-arid regions, with significant impact on water management and conservation. In narrow riparian zones, typical of much of the subhumid to semi-arid U.S., direct measurement of RET by eddy correlation is precluded by the limited fetch distance of riparian vegetation. Alternative approaches based on water balance analyses have a long history, but their accuracy is not well understood. Factors such as heterogeneity in soil properties and root distributions, and sparse measurements, introduce uncertainties in RET estimates. As part of a larger effort aimed at improving understanding of basin-wide RET using scaling theories, we installed a continuous monitoring system for water balance estimation at the scale of a single (~100 m long) reach along Rock Creek in the Whitewater Basin in central Kansas. The distinguishing features of this site include a vadose zone with fine-grained soils underlain by a phreatic zone of coarse gravel embedded in clay, overlying karst bedrock. Across the width (~40 m) of the riparian zone, we installed one transect of four wells screened at the bottom of the alluvium (6-7 m depth), each accompanied by a soil moisture profiler with capacitance sensors at 4 vertical levels above the local water-table elevation (~2.5 m depth) and a shallow well screened just below the water table. All wells were instrumented with pressure transducers for monitoring water levels. Additional sets of all sensors were installed at the upstream and downstream ends of the study reach. Initial results from the monitoring network suggest significant complexities in the behavior of the subsurface system at the site, including a high degree of heterogeneity. All deep wells show a rapid response to streamflow variations and nearby pumping. However, the shallow water-table wells do not respond rapidly to either. Both the shallow wells and soil

  3. Floodplain ecohydrology: Climatic, anthropogenic, and local physical controls on partitioning of water sources to riparian trees

    PubMed Central

    Singer, Michael Bliss; Sargeant, Christopher I; Piégay, Hervé; Riquier, Jérémie; Wilson, Rob J S; Evans, Cristina M

    2014-01-01

    Seasonal and annual partitioning of water within river floodplains has important implications for ecohydrologic links between the water cycle and tree growth. Climatic and hydrologic shifts alter water distribution between floodplain storage reservoirs (e.g., vadose, phreatic), affecting water availability to tree roots. Water partitioning is also dependent on the physical conditions that control tree rooting depth (e.g., gravel layers that impede root growth), the sources of contributing water, the rate of water drainage, and water residence times within particular storage reservoirs. We employ instrumental climate records alongside oxygen isotopes within tree rings and regional source waters, as well as topographic data and soil depth measurements, to infer the water sources used over several decades by two co-occurring tree species within a riparian floodplain along the Rhône River in France. We find that water partitioning to riparian trees is influenced by annual (wet versus dry years) and seasonal (spring snowmelt versus spring rainfall) fluctuations in climate. This influence depends strongly on local (tree level) conditions including floodplain surface elevation and subsurface gravel layer elevation. The latter represents the upper limit of the phreatic zone and therefore controls access to shallow groundwater. The difference between them, the thickness of the vadose zone, controls total soil moisture retention capacity. These factors thus modulate the climatic influence on tree ring isotopes. Additionally, we identified growth signatures and tree ring isotope changes associated with recent restoration of minimum streamflows in the Rhône, which made new phreatic water sources available to some trees in otherwise dry years. Key Points Water shifts due to climatic fluctuations between floodplain storage reservoirs Anthropogenic changes to hydrology directly impact water available to trees Ecohydrologic approaches to integration of hydrology afford new

  4. Sand and sandbar willow: a feedback loop amplifies environmental sensitivity at the riparian interface.

    PubMed

    Rood, Stewart B; Goater, Lori A; Gill, Karen M; Braatne, Jeffrey H

    2011-01-01

    Riparian or streamside zones support dynamic ecosystems with three interacting components: flowing water, alluvia (river-transported sediments), and vegetation. River damming influences all three, and subsequent responses can provide insight into underlying processes. We investigated these components along the 315-km Hells Canyon corridor of the Snake River that included reaches upstream, along, and downstream from three large dams and reservoirs, and along the Salmon River, a free-flowing tributary. Sandbar willow was generally the woody plant at the lowest bank position and was abundant along upstream reaches (53, 45, 67% of transects), sparse along reservoirs (11, 12, 0%), and sparse along the Snake River downstream (11%). It was prolific along the undammed Salmon River (83%) and intermediate along the Snake River below the Salmon inflow (27%), indicating partial recovery with the contribution of water and sediments. Along these rivers, it commonly occurred on sandy substrates, especially on shallow-sloped surfaces, and emerged from interstitial sands between cobbles on steeper surfaces. However, along the Snake River below the dams, sandbars have eroded and willows were sparse on remnant, degrading sand surfaces. We conclude that a feedback loop exists between sands and sandbar willow. Sand favors willow colonization and clonal expansion, and reciprocally the extensively branched willows create slack-water zones that protect and trap sands. This feedback may sustain surface sands and sandbar willows along free-flowing river systems and it amplifies their mutual vulnerability to river damming. Following damming, sediment-depleted water is released downstream, eroding surface sands and reducing willow colonization and expansion. With willow decline, sands are further exposed and eroded, compounding these impacts. From this feedback, we predict the coordinated depletion of surface sands and riparian willows along dammed rivers throughout the Northern Hemisphere

  5. Diversity of Riparian Plants among and within Species Shapes River Communities

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to

  6. Diversity of Riparian Plants among and within Species Shapes River Communities.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to

  7. Effects of experimental floods on riparian and aquatic ecosystems: Bill Williams River, Arizona

    NASA Astrophysics Data System (ADS)

    Shafroth, P. B.; Andersen, D. C.; Wilcox, A. C.; Kui, L.; Stella, J. C.

    2013-12-01

    Development of flow prescriptions for environmental purposes along rivers is relatively common, but implementation of these 'environmental flows' occurs infrequently. Implementation is critical for testing hypotheses relating flow regime to biotic response, which ultimately can inform adaptive flow management. We describe the development of flow prescriptions and evaluate responses of riparian vegetation, beaver dams, and associated aquatic habitat to experimental floods and intervening base flows associated with an environmental flow program on the Bill Williams River (BWR), in semiarid Arizona. First, we assessed effects of flow releases between 1993 and 2009 designed to favor the establishment and maintenance of native riparian trees (Populus and Salix) and disfavor an invasive, nonnative shrub (Tamarix spp.) downstream of Alamo Dam on the BWR. Our data are multi-scaled and include a several-decade assessment of changes to major vegetation types based on a time series of aerial photography, an assessment of species composition and abundance sampled in permanent vegetation quadrats, and targeted seedling surveys following experimental floods. Between 1993 and 2009, we observed significant increases in Populus and Salix forests and essentially no change in Tamarix. Experimental floods in 2006 and 2007 resulted in higher mortality of Tamarix seedlings than Salix. These results illustrate the potential for managing streamflow to influence riparian vegetation dynamics, including management of nonnative species. Second, we examined the role of beaver as ecosystem engineers in the BWR and linkages to flow releases between 2004 and 2013. Beaver convert lotic stream habitat to lentic through dam construction and maintenance during low flow periods, and the process is reversed when a flood or other event causes dam failure. We estimated the extent of lotic and beaver-created lentic (beaver pond) habitat along the BWR and related the likelihood of damage or destruction of

  8. Petroleum basins of Sakhalin and adjacent shelf

    SciTech Connect

    Mavrinski, Y.; Koblov, E. )

    1993-09-01

    Sixty-seven oil and gas fields have been discovered on Sakhalin and the adjacent shelf but the distribution of fields is uneven in north Sakhalin, south Sakhalin, and the Tatar basins. The sedimentary cover is composed of sandy, clayey, and siliceous rocks, with volcanogenic and coal-bearing deposits of Upper Cretaceous, Paleogene, and Neogene 8-12 km thick. Marine clayey and siliceous oil source rocks are regionally developed in the section at different stratigraphic levels; the organic matter is of mixed type and the content varies from 0.5 to 1.5%. The upper Oligocene and middle-upper Miocene source rocks in the north Sakhalin basin are typical, and the organic carbon content ranges from 1 to 5%. The level of organic matter catagenesis and conversion into hydrocarbons is high because of the high differential geothermal gradient in the basins, 30-50[degrees]C per km. Porous sandstones in the Miocene form the reservoirs in all fields with the exception of Okruzhnoye, where the pay zone is a siliceous claystone. Growth-fault rollovers and anticlines form the main traps ranging in area from 5 to 300 km[sup 2], with amplitudes between 100 and 600 m. both stratigraphic and structural traps have been identified. Considerable volumes of reserves are associated with the Miocene deposits of north Sakhalin, which are characterized by an optimum combination of oil source rocks, focused migration paths, and thick sequences of reservoirs and cap rocks. Six large fields have been discovered in the past 15 yr. Oil and condensate reserves stand at over 300 million MT, and gas reserves are about 900 billion m[sup 3].

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 it towards riparian management planning in HUC12 watersheds. Hig...

  10. AN INDICATOR OF POTENTIAL STREAM WOOD CONTRIBUTION FOR RIPARIAN FORESTS

    EPA Science Inventory

    In northwestern Oregon a key function of riparian forests is to provide wood to the stream network. This function is a prominent feature of Federal and State forest practices in the region. Thus, defining indicators which are associated with this function are important for desi...

  11. Plant Growth and Phosphorus Uptake of Three Riparian Grass Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers can significantly reduce sediment-bound phosphorus (P) entering surface water, but control of dissolved P inputs is more challenging. Because plant roots remove P from soil solution, it follows that plant uptake will reduce dissolved P losses. We evaluated P uptake of smooth bromegr...

  12. EFFECTS OF GEOMORPHIC PROCESSES AND HYDROLOGIC REGIMES ON RIPARIAN VEGETATION

    EPA Science Inventory

    In this chapter, the relationships among riparian vegetation and geomorphic and hydrologic processes in central Great Basin watersheds are evaluated over a range of scales. These relationships are examined through a series of case studies that have been conducted by the Great Ba...

  13. Monitoring vegetation water uptake in a semiarid riparian corridor

    NASA Astrophysics Data System (ADS)

    Robinson, J.; Ochoa, C. G.; Leonard, J.

    2015-12-01

    With a changing global climate and growing demand for water throughout the world, responsible and sustainable land and water resource management practices are becoming increasingly important. Accounting for the amount of water used by riparian vegetation is a critical element for better managing water resources in arid and semiarid environments. The objective of this study was to determine water uptake by selected riparian vegetative species in a semiarid riparian corridor in North-Central Oregon. Exo-skin sap flow sensors (Dynamax, Houston, TX, U.S.A.) were used to measure sap flux in red alder (Alnus rubra) trees, the dominant overstory vegetation at the field site. Xylem sap flow data was collected from selected trees at the field site and in a greenhouse setting. Transpiration rates were determined based on an energy balance method, which makes it possible to estimate the mass flow of sap by measuring the velocity of electrical heat pulses through the plant stem. Preliminary field results indicate that red alder tree branches of about 1 inch diameter transpire between 2 and 6 kg of water/day. Higher transpiration rates of up to 7.3 kg of water/day were observed under greenhouse conditions. Streamflow and stream water temperature, vegetation characteristics, and meteorological data were analyzed in conjunction with transpiration data. Results of this study provide insight on riparian vegetation water consumption in water scarce ecosystems. This study is part of an overarching project focused on climate-vegetation interactions and ecohydrologic processes in arid and semiarid landscapes.

  14. Impacts of feral horse use on rangelands and riparian areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feral (wild) horse impacts on rangelands and riparian areas are largely unknown. The impacts of feral horses are often indistinguishable from domestic livestock impacts because livestock grazing occurs across most horse herd management areas. However, the Sheldon National Wildlife Refuge has a lar...

  15. Riparian willow restoration at Arapaho National Wildlife Refuge

    USGS Publications Warehouse

    Auble, G.T.; Roelle, J. E.; TImberman, A.

    2006-01-01

    Riparian willow communities along the Illinois River at Arapaho National Wildlife Refuge in North Park near Walden, Colorado, provide important habitat for a number of wildlife species, including neotropical migratory birds. Existing stands in the northern (downstream) portion of the refuge are sparse and discontinuous (Photo 1) compared to upstream portions of the Illinois River and the parallel Michigan River.

  16. Riparian Sediment Delivery Ratio: Stiff Diagrams and Artifical Neural Networks

    EPA Science Inventory

    Various methods are used to estimate sediment transport through riparian buffers and grass jilters with the sediment delivery ratio having been the most widely applied. The U.S. Forest Service developed a sediment delivery ratio using the stiff diagram and a logistic curve to int...

  17. LINKING WATERFOWL WITH CONTAMINANT SPECIATION IN RIPARIAN SOILS

    EPA Science Inventory

    This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 38, Linking Waterfowl with Contaminant Speciation in Riparian Soils, implemented and funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U...

  18. EVALUATION OF METRIC PRECISION FOR A RIPARIAN FOREST SURVEY

    EPA Science Inventory

    This paper evaluates the performance of a protocol to monitor riparian forests in western Oregon based on the quality of the data obtained from a recent field survey. Precision and accuracy are the criteria used to determine the quality of 19 field metrics. The field survey con...

  19. Impacts of feral horse use on rangelands and riparian areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feral (wild) horse impacts on rangelands and riparian areas are largely unknown. The impacts of feral horses are often indistinguishable from domestic livestock impacts because livestock grazing occurs across most horse herd management areas. However, the Sheldon National Wildlife Refuge has a large...

  20. Distribution of cattle grazing in a northeastern Oregon riparian pasture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock grazing of a northeastern Oregon riparian pasture was monitored using high-frequency GPS tracking of cattle and high-resolution aerial photography. Tracking collars recorded positions, velocity, date, and time at 1-sec intervals. Areas where animals rested and moved were identified and re...

  1. RIPARIAN FOREST INDICATORS OF POTENTIAL FUTURE STREAM CONDITION

    EPA Science Inventory

    Large wood in streams can play an extraordinarily important role in influencing the physical structure of streams and in providing habitat for aquatic organisms. Since wood is continually lost from streams, predicting the future input of wood to streams from riparian forests is c...