5/23/2016  |   13:30 - 13:45   |  315

STREAM BIODIVERSITY IS DISPROPORTIONATELY LOST TO URBANIZATION WHEN FLOW PERMANENCE DECLINES: EVIDENCE FROM SOUTHWESTERN NORTH AMERICA Climate change is predicted to increase the frequency and magnitude of extreme weather events. Such events coupled with demand for freshwater to support rapidly growing cities may reduce flow permanence (FP) and threaten stream biodiversity. Here, we examined the role that FP and urbanization play in limiting stream biodiversity in the Austin, Texas, USA metropolitan area. We contrasted responses of macroinvertebrate communities to impervious cover (IC) among streams spanning a wide range of FP using long-term biomonitoring and discharge data collected across 104 sites. The number of Ephemeroptera, Plecoptera and Trichoptera taxa significantly and independently declined with increasing IC and decreasing FP. However, the decline in the number of all taxa as FP decreased depended on the level of IC; higher IC levels were associated with disproportionately greater declines in taxon richness. Threshold Indicator Taxa Analysis also revealed greater sensitivity in community response to IC at low FP compared to sites with high FP. These results imply that future urban growth may have disproportionately negative effects on streams forecasted to become increasingly intermittent due to climate change.

Ryan S. King (Primary Presenter/Author), Baylor University, Ryan_S_King@baylor.edu;


Mateo Scoggins ( Co-Presenter/Co-Author), City of Austin, Mateo.Scoggins@austintexas.gov;


Abel Porras ( Co-Presenter/Co-Author), City of Austin Watershed Protection Department, abel.porras@austintexas.gov;


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5/23/2016  |   13:45 - 14:00   |  315

EVALUATING FISH HABITAT COMPENSATION IN THE CANADIAN ARCTIC: STREAM HABITAT ATTRIBUTES AND MACROINVERTEBRATE ASSEMBLAGES Damage to stream ecosystems as a result of development often requires habitat restoration or compensation measures. A compensation project focused on improving ecosystem connectivity and fish habitat among three small fish-bearing lakes and their outlet streams was conducted on the Canadian tundra as a result of diamond mine development. We used a Before-After-Control-Impact design to evaluate the level of change in stream habitat attributes and macroinvertebrate assemblages following habitat manipulations. Two years post manipulation, changes observed in the streams did not appear to be significant ecologically, especially where disturbance was limited. Removal of riparian vegetation best explained the post-treatment reduction in coarse particular organic matter observed in some of the streams. Some shifts in relative abundances within the macroinvertebrate assemblages were observed, but changes were not detected for leaf litter processing rates, epilithon biomass, woody debris volume, or macroinvertebrate total abundance or diversity. By minimizing disturbance during construction activities, particularly to riparian vegetation, ecosystem structure and function and components of lower trophic levels can be retained following similar habitat manipulations.

Andrea Erwin (Primary Presenter/Author), University of Alberta, erwina1@cnc.bc.ca;


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5/23/2016  |   14:00 - 14:15   |  315

DISENTANGLING THE EFFECTS OF MULTIPLE STRESSORS IN LAKES; SHOULD WE USE LITTORAL BENTHIC INVERTEBRATES? Guidelines for efficient management of freshwaters are based on reliable bioindicators and their responses to varied stressors. The aim of our research was to develop hierarchical ranking scheme for environmental gradients reflecting landscape characteristics and stressors (land use, eutrophication, fish stocking and hydromorphological alteration) considering temporal and/or spatial covariates and to analyse responsiveness of lake littoral benthic invertebrate taxa to that gradients. Taxa and environmental data from lowland to alpine natural and artificial lakes were used. Partial canonical correspondence analysis revealed apparent dominance of catchment scale variables over lower spatial scale variables. Further, statistical significant differences in taxa responses along different environmental gradients imply that littoral benthic invertebrates are useful bioindicators for key stressors affecting lake ecosystems. Occurrences of sensitive taxa along all stressor gradients provide an evidence of wide applicability of littoral benthic invertebrates in bioassesment. According to our findings littoral benthic invertebrates show potential in disentangling the effect of multiple stressors and thus providing a key solution in lake management.

Rebeka Šiling (POC,Primary Presenter), Institute for Water of the Republic of Slovenia, rebeka.siling@izvrs.si;


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5/23/2016  |   14:15 - 14:30   |  315

INVESTIGATION OF THE INFLUENCE OF NATURALLY ELEVATED TOTAL DISSOLVED SOLIDS CONCENTRATIONS ON FRESHWATER BENTHIC MACROINVERTEBRATE STREAM COMMUNITIES IN THE SOUTHERN CALIFORNIA REGION. Elevated total dissolved solids (TDS) concentrations in streams are commonly observed in urban watersheds of Southern California, often above current water quality criteria. One of the key challenges in assessing the impact of urbanization on water quality is separation of natural conditions from anthropogenic sources. Coastal Southern California is characterized by uplifted marine sediments, while inland mountains are comprised primarily of igneous and metamorphic layers. Similarly, urbanization is concentrated near the coastline and decreases in density moving eastward. Due to these natural geologic features and Pacific Ocean proximity, groundwater in many sub-basins are naturally high in TDS, ranging from 500 to 3400 mg/L across San Diego County. While it has been well documented that TDS concentrations approaching 1,000 mg/L can negatively impact aquatic organisms, it is possible that BMI from this region are adapted to naturally high levels of TDS. This study’s purpose was to: 1) investigate the influence of underlying geology on TDS concentrations in surface waters, and 2) investigate effects of naturally elevated TDS concentrations/specific ions on BMI community structure that reside in the region’s streams.

John Rudolph (Primary Presenter/Author), Amec Foster Wheeler, john.d.rudolph@amec.com;


Ted Von Bitner ( Co-Presenter/Co-Author), Amec Foster Wheeler, theodore.vonbitner@amecfw.com;


Ruth Kolb ( Co-Presenter/Co-Author), City of San Diego Transportation & Storm Water, RKolb@sandiego.gov;


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5/23/2016  |   14:30 - 14:45   |  315

COMBINING LOCAL AND REGIONAL DATA TO IMPROVE ENVIRONMENTAL DECISION MAKING Regional data and local data provide different insights into the potential effects of management actions, and combining these two types of data may improve environmental decisions. Regional data are collected over large areas and span broad environmental gradients, and analyses of these data can provide robust estimates of relationships between environmental factors and biological responses. Conversely, local data often feature multiple samples from individual sites and can provide detailed knowledge of conditions at these sites, but estimates of relationships between environmental factors and biological responses can be uncertain because the data span a narrow range of conditions. We discuss statistical challenges and potential benefits of combining regional and local data. We illustrate these ideas using nutrient and microcystin data collected at the regional scale by the National Lakes Assessment and at the local scale by the Nebraska Department of Environmental Quality. We demonstrate how local data can be interpreted in the context of regional data to improve estimates of nutrient thresholds that protect against high microcystin concentrations.

Lester Yuan (Primary Presenter/Author), U.S. Environmental Protection Agency, yuan.lester@epa.gov;


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5/23/2016  |   14:45 - 15:00   |  315

SYNTHESIZING EVIDENCE TO ASSESS THE CAUSES OF SMALLMOUTH BASS DECLINES AT THE SUSQUEHANNA AND JUNIATA RIVERS, PENNSYLVANIA, USA Unusual mortality events of smallmouth bass (SMB) have been observed in the Susquehanna River Basin annually since 2005 and have coincided with a decline in recruitment of young-of-year fish into the adult SMB population. In 2014, the Pennsylvania Department of Environmental Protection (PADEP) in cooperation with the Pennsylvania Fish and Boat Commission (PFBC) initiated an effort to synthesize the large body of potentially relevant publications, data, and analyses. U.S. EPA’s stressor identification process, as described on the CADDIS website (CADDIS (www.epa.gov/caddis)) was selected for the assessment because it provides transparency and reduces bias without restricting the types of evidence used. Over 50 analytical worksheets comprising almost 400 pages describing data collections and analyses were developed and evaluated by experts over the course of three workshops. The causal assessment successfully narrowed the scope of concerns and will be used to guide future studies and management of the Susquehanna and Juniata Rivers. DISCLAIMER: The views expressed in this presentation are those of the author and do not necessarily reflect the views or policies of the U.S. EPA

Dustin Shull ( Co-Presenter/Co-Author), Pennsylvania Department of Environmental Protection, dushull@pa.gov;


Geoffrey Smith ( Co-Presenter/Co-Author), Pennsylvania Fish and Boat Commission, geofsmith@pa.gov;


Josh Lookenbill ( Co-Presenter/Co-Author), Pennsylvania Department of Environmental Protection, mlookenbil@pa.gov;


Susan Norton (POC,Primary Presenter), U.S.Environmental Protection Agency, norton.susan@epa.gov;


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