5/23/2016  |   13:30 - 13:45   |  311-312

UNDERSTANDING THE EXTENT OF FOOD WEB ALTERATIONS ON AQUATIC ECOSYSTEM STRUCTURE AND FUNCTION REQUIRES CAREFUL CONSIDERATION OF SCALE Species declines due to changing environmental conditions or anthropogenic influences such as fisheries harvest as well as species introductions probably have consequences beyond the species by also altering their food webs. The scope of the effect on the structure and function of aquatic ecosystems likely depends on the role of the affected species (e.g., grazer/consumer, ecosystem engineer, keystone species) and on the spatial and temporal scale considered. Spatial effects can be fairly small, like the introduction of a species in an individual pond or lake, or relatively large, like the decline of anadromous fish migrations affecting thousands of kilometers. Temporal effects may be short-term, such as loss of species due to drought which may be replenished from nearby source populations following rewetting, or long-term, such as the installation of a dam that alters natural flow and temperature regimes of rivers. Ultimately, to gain a better understanding of the implications of food web alterations, the potential pathways of influence need to be explicitly considered across various spatial and temporal scales to identify the challenges aquatic ecosystems face.

Janine Rüegg (POC,Primary Presenter), University of Lausanne, janine.ruegg@unil.ch;


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5/23/2016  |   13:45 - 14:00   |  311-312

HISTORICAL RECORDS OF FRESHWATER ECOSYSTEMS: USING PROTEIN BARCODING OF ARCHAEOLOGICAL SAMPLES TO PROVIDE TEMPORAL DATA One of the issues facing fisheries research is uncertainty regarding how fish populations will respond to changes in fishers’ behavior or the environment. The archaeological record, which can provide detailed, long-range histories of fisheries and their exploitation by humans, is an important resource to provide temporal data. However, fish bones are underrepresented in the archaeological literature because they are less stable than those of other taxa and identification using morphology to species is often difficult or impossible. ZooMS uses peptide fingerprinting of collagen as a method for rapid identification of archaeological bone to species. This technique has been used successfully for mammal bones in the archaeological record, but is considerably more difficult in fish due to the collagen diversity. Here I describe my work on adapting ZooMS for use on freshwater fish species in Western Europe using a case study from Medieval archaeological sites in York, UK during periods of changing fishing practices and river pollution. Combined with geological, DNA, and isotope data it is possible to begin reconstructing food webs in historic freshwater ecosystems.

Kristine Korzow Richter (Primary Presenter/Author), University of York (UK), kkr501@york.ac.uk;


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5/23/2016  |   14:00 - 14:15   |  311-312

COMPOUNDING IMPOUNDMENTS: AQUATIC INSECT DISTRIBUTION AND EMERGENCE IN A FRAGMENTED RIVERSCAPE Whereas a substantial amount of research has informed scientists and resource managers of the impacts dams have on aquatic ecosystems, relatively few studies have investigated biological impacts of multiple dams on a watershed scale. In this presentation we examine the distribution and emergence patterns of adult aquatic insects in regulated and unregulated reaches of the Colorado River basin. We employ a unique citizen science-based sampling protocol using light traps which allowed for the synchronous collection of emergent insect samples throughout the upper Colorado River basin which spans more than 2,500 rkm and is fragmented by five large dams. Sampling at this scale enables us to interpret aquatic-terrestrial linkages across large landscapes. Differences between tailwater ecosystems, spatial and temporal trends in insect emergence, and the cumulative effects of major infrastructure on insect distribution will be discussed.

Anya Metcalfe (Primary Presenter/Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, ametcalfe@usgs.gov;


Ted Kennedy ( Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, tkennedy@usgs.gov;


Jane Marks ( Co-Presenter/Co-Author), Northern Arizona University, jane.marks@nau.edu;


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5/23/2016  |   14:15 - 14:30   |  311-312

SEASONAL AND SPATIAL DIFFERENCES IN CUTTHROAT (ONCORHYNCHUS CLARKII CLARKII) AND STEELHEAD (O. MYKISS IRIDEUS) TROUT DIET AT HINKLE CREEK, OR., USA. Prey availability, fish life histories, and local hydrology contributed to differences in trout diet at 8 tributary and 6 main stem sites in of Hinkle Creek, OR where 15 fish per site per date were lavaged and replicate Surber samples were taken. In the lab macroinvertebrates and stomach contents were identified; prey were measured to determine biomass using length/weight regressions. In 2004 more terrestrial prey were eaten in summer (average 84%) compared to spring (average 36%). Consumption decreased significantly in fall (48% terrestrial). Dominant prey composition varied by season: aquatics and terrestrials in spring; primarily termites and ants, in summer, springtails in fall. Benthic abundances were similar between seasons, and also between tributaries and main stems. Replicate lavage samples were critical in identifying spatial differences associated with trout life history strategies. In Spring 2005, smaller trout in tributaries spent more energy in high gradient reaches and ate more than larger fish in main stem sites. Higher survival costs in tributaries and reliance on terrestrial invertebrates emphasize the importance of riparian vegetation in providing critical terrestrial resources.

Judy Li (Primary Presenter/Author), Oregon State University, judyli@comcast.net;


William Gerth ( Co-Presenter/Co-Author), Oregon State University, william.gerth@oregonstate.edu;


Richard VanDriesche ( Co-Presenter/Co-Author), Oregon State University, Richard - FW Van Driesche ;


Douglas Bateman ( Co-Presenter/Co-Author), Oregon State University, fatcutty2@gmail.com;


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5/23/2016  |   14:30 - 14:45   |  311-312

HYDROLOGY AND FISH COMPOSITION DRIVES LENTIC FOOD WEB STRUCTURE IN ARCTIC ALASKA Climate change in the Arctic is expected to change the physical environment of freshwater ecosystems. Changes in surface water dynamics, such as the timing, duration, and accessibility of water during the ice-free season, will influence fish species distribution and food web patterns. To better understand and predict future energy flow in freshwater systems of the Arctic Coastal Plain, Alaska, we examined how differences in surface water hydrology affect fish distribution and food web structure in 32 lentic water bodies at two locations over a range of local and regional surface water connectivity. Reduced fish species richness in isolated locations limited the number of trophic levels, seemingly due to exclusion of top fish predators. Preliminary analyses suggest that fish species assemblage and fish dietary habits influenced invertebrate assemblages. Fish distributional patterns across water bodies, including systems with single fish species or multiple fish species, influenced lower trophic levels differently. In summary, the affect of surface water connectivity on fish distributions, and fish presence on invertebrate assemblages, leads to a broad range of unique lentic food web structures across the broader landscape.

Sarah Laske (Primary Presenter/Author), Alaska Cooperative Fish and Wildlife Research Unit, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, slaske@alaska.edu;


Amanda Rosenberger ( Co-Presenter/Co-Author), U.S. Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit, University of Missouri , rosenbergera@missouri.edu ;


Mark Wipfli ( Co-Presenter/Co-Author), University of Alaska Fairbanks, mwipfli@alaska.edu;


Christian Zimmerman ( Co-Presenter/Co-Author), U.S. Geological Survey, Alaska Science Center, czimmerman@usgs.gov;


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5/23/2016  |   14:45 - 15:00   |  311-312

RIPARIAN THINNING: EVALUATING THE ECOLOGICAL TRADEOFFS OF TEMPERATURE AND PRODUCTIVITY FOR HEADWATER STREAMS IN REDWOOD ECOSYSTEMS OF NORTHERN CALIFORNIA Silvicultural techniques like thinning are being applied to forested landscapes to restore old-growth forests in redwood ecosystems. Although most thinning treatments have occurred in upland forests, thinning may also benefit second-growth riparian forests. Before widespread thinning treatments are applied to riparian forests, however, it is essential that we evaluate the effects on stream ecosystems. To address this, we are evaluating the effects of riparian thinning on headwater streams in redwood ecosystems of coastal Northern California. We will address the effects of riparian thinning on: 1) Forest cover, light, and stream temperature; 2) Energy flow and pathways of productivity; and 3) Growth and bioenergetics of stream amphibian and fishes. This research will attempt to understand how stream-riparian food webs function across seasons and entire watersheds by documenting the underlying mechanisms driving the responses by stream amphibian and fish communities to riparian thinning. To do this, we will combine empirical data collection with stream network, food web, and bioenergetics modeling. By evaluating the cumulative effects associated with riparian thinning on aquatic ecosystems, we hope to guide riparian forest management in redwood ecosystems.

David Roon (Primary Presenter/Author), Oregon State University, david.roon@oregonstate.edu;


Jason Dunham ( Co-Presenter/Co-Author), U. S. Geological Survey, jdunham@usgs.gov;


Bret Harvey ( Co-Presenter/Co-Author), USFS, bharvey@fs.fed.us;


J. Ryan Bellmore ( Co-Presenter/Co-Author), Forest Service, Pacific Northwest Research Station, Juneau, AK, jbellmore@fs.fed.us;


Dede Olson ( Co-Presenter/Co-Author), USFS, dolson@fs.fed.us;


Gordie Reeves ( Co-Presenter/Co-Author), USFS, greeves@fs.fed.us;


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