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Effects of the Rio Salado Confluence on Benthic Substrate in the Rio Grande Harmony Lu REU Project Summer 2010

Effects of the Rio Salado Confluence on Benthic Substrate in the Rio Grande

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Effects of the Rio Salado Confluence on Benthic Substrate in the Rio Grande. Harmony Lu REU Project Summer 2010. Background. River Continuum Concept to Network Hypothesis gradient of change from headwaters to mouth of hydrological properties - PowerPoint PPT Presentation

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  • Effects of the Rio Salado Confluence on Benthic Substrate in the Rio GrandeHarmony LuREU ProjectSummer 2010

  • BackgroundRiver Continuum Conceptto Network Hypothesisgradient of change from headwaters to mouth of hydrological propertiesbiological communities also change to match the local conditionsdiscontinuities in these gradients occur, instead view the river as a network

  • BackgroundFlood events in an intermittent stream

  • Research QuestionsAre there observable effects from the confluence of an intermittent stream, the Rio Salado, on the main channel, the Rio Grande?Do these effects alter the local habitat?

  • Possible lasting effects of an intermittent tributary

    focus on substrate variation in the main channelwater energy determines particle carriage/depositiontributary carries sediment into main channelbenthic substrate important habitat characteristic

  • BackgroundRio Grandemajor water source for agriculture, domestic use, natural habitats (riparian areas)also is a habitat itself for many speciessandy-bottomed with wide floodplain

  • BackgroundInvertebrate communities are useful biological indicators in freshwatercommonly studiedmany are sedentary and provide assessment of localized effectsare important parts of river communities

  • Research SiteSevilleta National Wildlife Refuge

  • Research Site

  • Procedure 1 mapping11 transects from the west bank to the east bank4 samples along each transectat each site, 3 measurements:% cobbledepthsediment sample taken for texture analysis

  • Procedure 2 invertebrate sampling2 sets of samples taken (Day 1: June 4+6, Day 2: June 23)7 sites along the west bankData from each site (3 types):sediment texturewater characteristicsinvertebrate community

  • Invertebrate Sampling Sites

  • Procedure invert collectionInvertebrate sampling:- sediment core sampling4 cores of the top 1 cm of benthic substratesamples preserved in 70% ethanol

  • Procedure sample analysisSedimenthydrometer soil texture analysis used to assess % compositionInvertebrateinvertebrates separated from debris/sedimentidentified to Order or Family using dissecting microscope

    DaySiteChironomidaeSimuliidae TricorythidaeBaetidaeLeptoceridaeHempiteraOdonataCladocera1151200000012370010001311140300001417653000000

  • Results and DiscussionConfluence mapInvertebrate communityEnvironmental influence on invertebrate communityLasting effects of the confluence

  • Confluence Depth MapRio Salado

  • Confluence Cobble Cover MapRio Saladobubble size indicates % cobble cover

  • Invertebrate Data

  • Invertebrate Community Data (Global R): 0.536p: 0.001Similarity of communities positioning around confluenceMultidimensional Scaling (MDS)

    multivariate can look at community as a whole each sites community data viewed as a matrix calculated a similarity between all of the matrices plot similarity in multidimensional space compress to 2D plot with meaningless axis

    Bottom line:relative distance is keycloseness implies similarity

  • Invertebrate Community Data (Global R): 0.536p: 0.001Temporal Changes succession of species over the summer

  • Correlation between environment and biological communities water characteristics: showed very small variation between sites sediment texture: much higher variation between sites BEST analysis: compares environmental information (soil texture) to biological information (community)- % gravel and % vv fine sand + silt explain most of the variation in biological communities

    CorrelationVariables0.330gravel, vv fine sand + silt 0.330gravel, vv fine sand + silt,v fine sand 0.321gravel, vv fine sand + silt

  • MDSsize indicates relative % gravelsize indicates relative % vv fine sand + silt

  • Confluence Sand MapRio Saladobubble size indicates % sand (by mass)

  • Confluence Gravel MapRio Saladobubble size indicates % gravel (by mass)

  • Rio SaladoConfluence vv fine sand and silt Mapbubble size indicates % (by mass)gravelsiltvv fine sand

  • Matching up to observationsRio Salado

  • ConclusionsInvertebrate communities changed through timeVariation in invertebrate communities could be correlated with substrate qualitiesThe main channel around the confluence shows high variation in substrate qualityPatterns of substrate quality match observations of tributary inputsImplications that tributary has lasting influence on habitat quality of main channel

  • Further ResearchIntermittent streams as sources of disturbance that change throughout the yearInterannual variation of precipitation and flow rates of intermittent tributariesVariability in the benthic substrate of the Rio Grande overall (temporal and spatial)

  • AcknowledgementsAyesha Burdett, Jennifer JohnsonSevilleta LTER REU 2010 students (Christopher Shepard, Shayla Burnett, Amanda Labrado, Ricardo Duran, Cynthia Malone, Ileana Betancourt, Melissa Shaginoff, Mitch Nakai, Natasha Ribeiro, Amanda Liebrecht, Antonio Nevarez, Elida Iniguez)Brenda NietoNational Science FoundationSevilleta National Wildlife Refuge & LTER

  • ReferencesBenda, L., N.L. Poff, D. Miller, T. Dunne, G. Reeves, G. Pess, M. Pollock. (2004). The Network Dynamics Hypothesis: How Channel Networks Structure Riverine Habitats. BioScience. 54: 413-427.Best, J.L. (1988). Sediment transport and bed morphology at river channel confluences. Sedimentology. 35: 481-498.Burdett, A, R. Bixby. (2008). Effects of nutrient availability on periphyton growth and diversity in the Middle Rio Grande: top-down and bottom-up factors. Middle Rio Grande Endangered Species Collaborative Program Annual Report. 1-53.Duan, X., Z. Wang, M. Xu, K. Zhang. (2009). Effect of streambed sediment on benthic ecology. International Journal of Sediment Research. 24: 325338.Gensler, G. R. Oad, K. Kinzli. (2009). Irrigation System Modernization: Case Study of the MiddleRio Grande Valley. Journal of Irrigation and Drainage Engineering. 169-176.Kiffney, P.M., C.M. Greene, J.E. Hall, and J.R. Davies. (2006). Tributary streams create spatial discontinuities in habitat, biological productivity, and diversity in mainstem rivers. Can. J. Fish. Aquat. Sci. 63: 25182530.Palmer, M.A., H.L. Menniger, E. Bernhardt. (2010). River restoration, habitat heterogeneity and biodiversity: a failure of theory or practice? Freshwater Biology. 55: 205222.Rice, S.P., M.T. Greenwood, C.B. Joyce. (2001). Macroinvertebrate community changes at coarse sediment recruitment points along two gravel bed rivers. Water Resources Research. 37: 27932803.Rice, S.P., R.I. Ferguson, T.B. Hoey. (2006). Tributary control of physical heterogeneity and biological diversity at river confluences. Can. J. Fish. Aquat. Sci. 63: 25532566.Svendsen, K.M., C. E. Renshaw, F.J. Magilligan, K.H. Nislow, J.M. Kaste. (2009). Flow and sediment regimes at tributary junctions on a regulated river: impact on sediment residence time and benthic macroinvertebrate communities. Hydrol. Process. 23: 284296.Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell, C.E. Cushing. (1980). The River Continuum Concept. Can. J. Fish. Aquat. Sci. 37: 130-137.

  • Questions?

    Background conceptual ideas.Define river continuum conceptBUT [click] life is more complicatedRiver continuum concept probably too simple to really capture things, for ex: Confluence place where two rivers meetMay have water at different gradient, energy and therefore cause a sudden change in the gradient. Thus, a sudden local change creating a different habitat and increasing the overall heterogeneity of the riverInstead, look at it from the perspective of a complicated, complex drainage networkAdditionally, less is known about rivers in arid and semi-arid environments.

    River continuum concept diagram: http://science.kennesaw.edu/~jdirnber/limno/LecStream/RCC.jpgRio diagram: http://nm.water.usgs.gov/nawqa/riog/images/basinmap.jpg*Hydrology of water in arid and semi arid environments is unique.precip will often occur rarely but with more at once (monsoon season) leading to the high probs that it will be enough to exceed flood thresh holds and have overland flow.Thus, in arid environment, streams that only flow occasionally intermittent are commonAn intermittent stream is one that doesnt always have flowing water in it. With enough rainfall, the river will flood and have running waterEMPHASIZE THAT ONLY SOME OF THE YEAR THERE IS WATERFlooded arroyo picture: http://farm4.static.flickr.com/3409/3571502166_53863fc588.jpg?v=0*Interested in this arid land confluence stuff: PARTICULARLY IN THE FACT THAT EPHEMERAL CONFLUENCES AND WHETHER THEY HAVE LASTING EFFECTS DESPITE THE FACT THAT THEY ARE NOT FLOWING YEAR ROUND, LIKE A REGULAR CONFLUENCE

    But Im a biologist at heart, so Im really interested in how this hydrology may be affecting the organisms present*What are the effects that an int trib confluence might have?Fluid dynamics tells us that how fast the river flows and this will change at a confluence. Sediment carriage and deposition will also be very important for a seasonal, int stream that will flow at varying rates throughout the year strong in the monsoon (such as now) and then down to none for the rest of the yearSubstrate is one of the most important characteristics that determines the stream habitatTherefore my focus will be on the benthic substrate of the rio grande main channel around this confluenceSand: http://www.tomi.com.my/products/SievedRiverSand2.jpgGravel: http://www.tomi.com.my/products/LandscapingDrainage.jpg*A bit about the Rio Grande Its important to understand! I want to look at it as a habitat (which is of course an important consideration for other aspects)Much river work focuses on gravel or cobbly bottomed streams, also, again, semi-arid environment*To assess Rio Grande as a habitat, I will look at the INVERTEBRATE communities.Why is this good?Commonly studied much is known about themWidespread can compare to other systemsSimuliidae: http://www.troutnut.com/im_regspec/picture_2742_small.jpgChronomid: http://starcentral.mbl.edu/msr/rawdata/viewable/chironomus_1097783931_esmlaw.jpgHeptagonaiid: http://bugguide.net/images/cache/HQARYK1RKQYQ20H020H070FQ80WRHQBRHQ9RYKYQ50BRFKTQHQFR9000P0K0U0L0SQQ0N0JQ80URJK1RG0FQ80TQZQ.jpgCopepod: http://fmel.ifas.ufl.edu/images/male1.jpgOstracod: http://nathistoc.bio.uci.edu/crustacea/Ostracoda/DSCF0052a.jpgHydraracina: http://cfb.unh.edu/CFBkey/html/Organisms/otherarthropods/SOHydracarina/water_mite_lg.jpg*AT THE SEVBlue is RGYellow is RS*Close up!*Two parts:1 map the confluence: physical effects that the Rio Salado may have on the confluence2 sample the invertebrate communities: for habitat proxy- transects 25 m apart relative Depth provide (river changes height) will talk more about sediment texture analysis later*Note first sampling spread out over two daysAll water parameters taken before any entrance into the waterWill be able to pair physical habitat data with community dataYsi picture: http://www.hualix.com/imagenes/MO-YSI-85.jpgInverts picture: http://www.nzfreshwater.org/pictures/macroinvertebrate_collage.jpg*Then sampled for inverts. Subsample of the confluence map7 sites along west bank (from upstream to downstream is 1-7)Upstream/downstream separated by 25 m3 around confluence*This sampling method of invertebrates aims to give a quantifiable area- cores taken at top 1 cm because that is where the majority of epibenthic inverts live (reference??)- pictures show process of washing out excess debris from the samples before preserving them*Sediment notes: % comp by massInvert notes: this took forever and a day this gives information about the community (whats present of each type and amount) of inverts present at each site*This is the order. It will flow together*Dark is deep. Light is shallow. Well come back to this.*Bubble size: bigger is higher %, smaller is less. Again, well be back.*Remember 1-7 is from up to down, 3 is at upstream corner of confluence, 4 in the middle.Day 1 samples from first week of June, Day 2 sampling at 3 week of JuneAbundance increases after the confluence. Generally higher taxonomic richness in the second set of samples*Multi multivariate: looking at the whole community.Used this as a matrix, then assembled similarity matrix comparing all of these communities. Then plotted on this 2D plane with meaningless axis.Bottom line: the relative distance is key closer is more similarALL OF THE FOLLOWING MDS GRAPHS ARE OF THE SAME THING but I will be highlighting different aspects

    Here, they are labeled by site. I have highlighted the fact that I think they are assembled into 3 sort of clusters of similarity.*(review, this is the same chart as you just saw, but Ive changed some colors)Remember how I took two sets of samples, approx 2.5 weeks apart?Blue clustered all on one side, red clustered on the other. Horizontal differentiationTemporal change! Succession of community through time! Likely due to the species life cycles and seasonality*Now lets connect the physical to the biological communities.Screw water data. It was boringSo sediment textures are more interesting. I looked at themSoil texture analysis also gave me multivariate info the % composition of sand silt clay etc. so assemble that matrix and pair with the matrix of bio comm data for each site.BEST (bio/enviro) analysis to determine which aspect of the enviro explains most of the variation in communities.Gravel and silt whoo*Back to MDS (again, same charts)Now I highlighted Gravel and Silt.Bubble size again indicates how high % comp is.Look, a trend of vertical grouping of communities: top are gravel based, bottom have more sand +silt*So now that I have established a relationship between the environ & sediment and the biological community, lets go back to my map of the confluence to see how this may effect the distribution of biological communities around the confluence and get at the idea of how the confluence effects the local habitat.Remember that the bubble size indicates the mass % at that areaSome maps, such as the sand, showed little pattern. Equally distributed everywhere*% gravel was the most highly correlated with the invert community. Here is what it looked like. It shows a more wider range of values with a particular distribution around the confluence.point out areas w/o gravel*Vv fine silt and sand was also important in determining biological communities. It also had a wide variation in the area and showed a particular pattern of distribution.In general, it was a reverse pattern of the gravel distribution.*Remember that I sampled before the monsoon season this year. Before Rio Salado had any water in it. I am looking for a lasting influence. Does what happens when there is water in the Salado match up?*