Tuesday, May 19, 2015
13:30 - 15:00

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13:30 - 13:45: / 102C LEAF DECOMPOSITION AND SECONDARY PRODUCTION AS INDICATORS OF LAND-COVER CHANGE IN TROPICAL RIVERS

5/19/2015  |   13:30 - 13:45   |  102C

LEAF DECOMPOSITION AND SECONDARY PRODUCTION AS INDICATORS OF LAND-COVER CHANGE IN TROPICAL RIVERS One of the largest threats to the integrity of aquatic ecosystems is the loss of riparian vegetation. Aquatic invertebrates contribute to leaf decomposition (LD), a fundamental process for energy release in small rivers, and form part of the secondary production (SP). These processes can be used as indicators of change in ecosystem functioning. This study assessed the effects of riparian deforestation at different spatial scales on: 1. physical-chemical parameters of rivers; 2. macroinvertebrate community structure and 3. ecosystem processes (LD and SP). The study was conducted in 27 sites of four tropical headwater streams. We used satellite images to quantify the riparian vegetation cover as a gradient of deforestation. Results showed that NH4 concentrations increased with increasing impact and shredders and over all richness were higher in the forest. LD decreased with deforestation and NH4 and was negatively related to shredder SP. LD was related to EPT taxa, SP, and %EPT. Our data suggest that loss of riparian vegetation has a significant impact on ecosystem processes and macroinvertebrate community structure, which in turn can be used as indicators of impact.

Eduardo F. Silva-Júnior (Primary Presenter/Author), Universidade do Estado do Rio de Janeiro, eduardobioadventure@gmail.com ;


Monalisa Silva-Araújo (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, monalisa.araujo.bio@gmail.com;


Flavia Tromboni (Co-Presenter/Co-Author), University of Nevada, Reno, ftromboni@unr.edu;


Rafael Feijó de Lima (Co-Presenter/Co-Author), University of Montana, rafael.feijo@mso.umt.edu;


Christine Lourenço-Amorim (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, chris.lourenco@ig.com.br;


Vinicius Neres-Lima (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, vinicius.lima.eco@gmail.com;


Steven Thomas (Co-Presenter/Co-Author), University of Alabama, sathomas16@ua.edu;


Eugenia Zandona (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, eugenia.zandona@gmail.com;


Timothy P. Moulton (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, moulton.timothy@gmail.com;


13:45 - 14:00: / 102C MITIGATING LEGACY AND FUTURE NUTRIENT LOADS AT THE LANDSCAPE AND WATERBODY SCALE USING GOOD QUALITY CARBON AS A TOOL

5/19/2015  |   13:45 - 14:00   |  102C

MITIGATING LEGACY AND FUTURE NUTRIENT LOADS AT THE LANDSCAPE AND WATERBODY SCALE USING GOOD QUALITY CARBON AS A TOOL The legacies of past nutrient loading to groundwater and surface waters by land use changes have left their mark on aquatic ecosystems. Nutrient concentrations continue to escalate even after significant reductions in external nutrient loading from point and non-point sources. Positive water quality responses following external nutrient reductions are influenced by the quantity and quality of carbon available in the system. Reduction of carbon through disconnection of floodplain and riparian wetlands adjacent to streams and rivers have depleted carbon-rich sources that provide the mechanism and driving factor for nutrient cycling and subsequent nutrient removal from aquatic systems. Emerging technologies aimed at alleviating carbon limitation using carbon amendments and innovative re-vegetation methodologies have proven to be very effective at reducing nutrient loads into aquatic resources. The key is to understand and reintroduce the appropriate conditions and levels of bioavailable carbon fractions that vary from labile to refractory to optimize the nutrient removal efficiency of a landscape or aquatic ecosystem. Specific strategies for using various sources of carbon to mitigate the effects of nutrients on groundwater and lotic systems will be highlighted.

Mary Szafraniec (Primary Presenter/Author), Amec Foster Wheeler Environment & Infrastructure, mary.szafraniec@amecfw.com;


14:00 - 14:15: / 102C THE EFFECTS OF LAND COVER AND CLIMATE ON NUTRIENT LOSS AND RETENTION IN HUMAN DOMINATED WATERSHEDS

5/19/2015  |   14:00 - 14:15   |  102C

THE EFFECTS OF LAND COVER AND CLIMATE ON NUTRIENT LOSS AND RETENTION IN HUMAN DOMINATED WATERSHEDS Anthropogenic activity strongly alters nutrient transport and processing in watersheds, particularly in agricultural and urban lands. We sought to determine how land cover and climate interact to influence nutrient losses from 78 sites in Minnesota. Five year average annual loads (2007 – 2011), encompassed a period of substantial variation in runoff. Overall, watersheds with lower runoff had greater N retention across a wide range of land use. Wetland cover is positively related to retention when N inputs are high, but negatively related and more variable when inputs are low. Sites in Northern Minnesota have low N retention because their losses of all forms of N are high relative to their low anthropogenic inputs. In highly agricultural watersheds, more wetland cover is associated with lower TKN and NO3 + NO2 losses and higher TN retention. Remnant lakes and wetlands are important to mitigating anthropogenic impacts on watersheds. Human dominated watersheds with lakes and wetlands (and potentially lower amounts of tile-drained fields) may retain more water and nutrients.

Evelyn Boardman (Primary Presenter/Author), University of Minnesota, eboardma@gmail.com;


Jacques Finlay (Co-Presenter/Co-Author), University of Minnesota, jfinlay@umn.edu;


14:15 - 14:30: / 102C LAND USE INTERACTIONS DRIVE SOUTHWESTERN ONTARIO STREAM NUTRIENT CONCENTRATIONS

5/19/2015  |   14:15 - 14:30   |  102C

LAND USE INTERACTIONS DRIVE SOUTHWESTERN ONTARIO STREAM NUTRIENT CONCENTRATIONS Land use activities such as agriculture and urbanization have transformed the landscape in southwestern Ontario and contributed to eutrophication of tributaries and downstream lakes. To quantify the cumulative influence of spatial patterns in land use and land cover on nutrient concentrations in tributaries of Lakes Erie and Huron, we sampled 29 river sites spanning a gradient in land use (60 – 90% agriculture) and phosphorus concentrations (0.0003 – 0.575 mg/L). Ordinary least squares regression identified significant, positive relationships between many nutrient parameters (e.g., TKN, TN, SRP and TP) and land use descriptors with the strongest being NH3-, which was driven by a combination of agricultural land use in the watershed and the population served by sewage treatment plants (similar to TKN and SRP). In contrast, concentrations of TN and TP were only associated with the population served by sewage treatment. Our results showed that even in this highly modified landscape, increases in specific nutrient parameters are associated with identifiable human activities. The results from this study will help inform nutrient criteria development and management recommendations for Lake Erie tributaries.

Kathryn Thomas (Primary Presenter/Author), Environment Canada, katie.thomas@ec.gc.ca;


Renee Lazor (Co-Presenter/Co-Author), Western University, rlazor@uwo.ca;


Patricia A. Chambers (Co-Presenter/Co-Author), Environment and Climate Change Canada, 867 Lakeshore Rd., Burlington Ontario, Canada, L7R 4A6, patricia.chambers@canada.ca;


Adam G. Yates (Co-Presenter/Co-Author), Western University & Canadian Rivers Institute, adam.yates@uwo.ca;


14:30 - 14:45: / 102C NUTRIENT/SEDIMENT RUNOFF AND ECOLOGICAL CONDITION: LINKING THE SWAT-VSA MODEL WITH EMPIRICAL MEASURES

5/19/2015  |   14:30 - 14:45   |  102C

NUTRIENT/SEDIMENT RUNOFF AND ECOLOGICAL CONDITION: LINKING THE SWAT-VSA MODEL WITH EMPIRICAL MEASURES Management of nonpoint sources of nutrients and sediments is the primary challenge for improving conditions within the Susquehanna-Chesapeake Basin. While ecological indicators are widely used to assess stream integrity, a direct link between nutrient and sediment stressors and ecological response remains ambiguous. This is partly due to the difficulty of obtaining high-resolution empirical measurements of nutrients and sediments. However, models that simulate runoff can be a more practical option. The Soil and Water Assessment Tool with Variable Source Area Hydrology (SWAT-VSA) is one such model and was recently used in WE38, a small upland agricultural watershed in Pennsylvania that drains into Mahantango Creek. Correlations between ecological condition and nutrient and sediment pollution have been explored by comparing model outputs of nitrate, phosphorus, and sediment with landscape metrics, the Stream-Wetland-Riparian Index, and the Pennsylvania Department of Environmental Protection Index of Biotic Integrity for benthic macroinvertebrates. This research is a key step in linking a promising area of nonpoint management – nutrient and sediment modeling – with the ecological conditions of streams within the Susquehanna-Chesapeake basin.

Claire Hirt (Primary Presenter/Author), University of Maryland, ccregan@umd.edu;


Susan Yetter (Co-Presenter/Co-Author), Penn State University, sel131@psu.edu;


Tameria Veith (Co-Presenter/Co-Author), USDA-ARS, tamie.veith@ars.usda.gov;


Amy Collick (Co-Presenter/Co-Author), USDA-ARS, amy.collick@ars.usda.gov;


Robert Brooks (Co-Presenter/Co-Author), Penn State University, rpb2@psu.edu;


14:45 - 15:00: / 102C IMPACTS OF MOUNTAINTOP REMOVAL MINING AND VALLEY FILLS ON STREAM SALAMANDER OCCUPANCY, ABUNDANCE AND SPECIES RICHNESS

5/19/2015  |   14:45 - 15:00   |  102C

IMPACTS OF MOUNTAINTOP REMOVAL MINING AND VALLEY FILLS ON STREAM SALAMANDER OCCUPANCY, ABUNDANCE AND SPECIES RICHNESS Across central Appalachia, mountaintop removal mining with valley fills (MTR/VF) is a dominant stressor of stream ecosystems. We examined the effects of MTR/VF on occupancy, abundance and species richness of stream salamanders in southeastern Kentucky. We found mean occupancy (across all species) in MTR/VF streams was 0.50 and mean occupancy in control streams was 0.87 suggesting that salamanders have a higher probability of occupancy in streams that have not been impacted by MTR/VF. Additionally, across all species, estimated mean abundance given occupancy was lower at MTR/VF sites. Furthermore, the mean species richness for MTR/VF streams was 2.27 whereas richness was 4.67 for control streams. Numerous mechanisms may be responsible for decreased occupancy, abundance and species richness at MTR/VF streams, although water chemistry may be particularly important. Indeed, mean specific conductance was 30 times greater, sulfate (SO4) levels were 70 times greater, and concentrations of dissolved ions (Ca, Mg, K, Na) were greater in MTR/VF streams than in control streams. Our findings suggest that stream salamanders appear to be particularly sensitive to MTR/VF.

Steven Price (Primary Presenter/Author), University of Kentucky, steven.price@uky.edu;


Brenee' Muncy (Co-Presenter/Co-Author), University of Kentucky, Brenee.muncy@uky.edu;


Simon Bonner (Co-Presenter/Co-Author), University of Kentucky, simon.bonner@uky.edu;


Chris Barton (Co-Presenter/Co-Author), University of Kentucky, barton@uky.edu;


Andrea Drayer (Co-Presenter/Co-Author), University of Kentucky, andrea.drayer@uky.edu;