Monday, May 23, 2016
15:30 - 17:00

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15:30 - 15:45: / 307 DROUGHT EFFECTS ON VERTEBRATE BIOTA IN HEADWATER STREAMS OF THE CASCADE MOUNTAINS, OR

5/23/2016  |   15:30 - 15:45   |  307

DROUGHT EFFECTS ON VERTEBRATE BIOTA IN HEADWATER STREAMS OF THE CASCADE MOUNTAINS, OR Summer discharge in 2015 was the lowest on record in much of western Oregon. We assessed impacts of this drought on coastal cutthroat trout (Oncorhynchus clarkii clarkii) and coastal giant salamander (Dicampton tenebrosus) in headwater ecosystems by comparing abundances, biomass, and condition factor in 9 streams between 2014 and 2015. Trout abundance and biomass were significantly lower in 8 of 9 streams in 2015 (p=0.007 and p=0.037, respectively). Mean trout condition factor was also lower in 7 of 9 streams, however the overall response was not significant at alpha = 0.05. Changes in juvenile trout abundance were inconsistent (increases in 5 streams and decreases in 4 streams), however, juvenile mean length was greater in all 9 streams in 2015 relative to 2014 (p=0.002). Salamander abundances and biomass varied in response with no clear trend. However, salamander mean condition factor was lower in all 9 streams in 2015 (p= <0.001). None of the abundance, biomass, condition or size results were correlated with temperature. These results suggest that even in relatively cold streams cutthroat trout populations may not be buffered against drought.

Matthew Kaylor (POC,Primary Presenter), Oregon State University, matthew.kaylor@oregonstate.edu;


Dana Warren ( Co-Presenter/Co-Author), Oregon State University, dana.warren@oregonstate.edu;


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15:45 - 16:00: / 307 THE INFLUENCE OF DROUGHT ON FLOW-ECOLOGY RELATIONSHIPS IN OZARK HIGHLAND STREAMS

5/23/2016  |   15:45 - 16:00   |  307

THE INFLUENCE OF DROUGHT ON FLOW-ECOLOGY RELATIONSHIPS IN OZARK HIGHLAND STREAMS Drought and summer drying can have strong effects on abiotic and biotic aspects of stream ecosystems. We examined flow-ecology relationships in the Ozark Highlands over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013). We examined metrics of community structure in fish, crayfish and macroinvertebrates using predictor variables incorporating hydrology, habitat, geomorphology, and water quality. We found that hydrology was an important variable influencing community structure, but often less important than other types of environmental variables, especially in a drought year. We found substantial between-year variation in flow-ecology relationships. Ecological responses that we observed differed significantly between drought and flood years, and this highlights the importance of understanding temporal variation in flow-ecology relationships for resource planning.

Dustin Lynch ( Co-Presenter/Co-Author), Oklahoma State University, dustin.lynch@okstate.edu;


Doug Leasure ( Co-Presenter/Co-Author), University of Georgia, doug.leasure@gmail.com;


Daniel Magoulick (Primary Presenter/Author), Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, danmag@uark.edu;


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16:00 - 16:15: / 307 RUNNING DRY: DROUGHT INDUCED TRANSCRIPTOME-WIDE GENE EXPRESSION IN THE AQUATIC CADDISFLY LARVAE MICROPTERNA LATERALIS (INSECTA: TRICHOPTERA)

5/23/2016  |   16:00 - 16:15   |  307

RUNNING DRY: DROUGHT INDUCED TRANSCRIPTOME-WIDE GENE EXPRESSION IN THE AQUATIC CADDISFLY LARVAE MICROPTERNA LATERALIS (INSECTA: TRICHOPTERA) Drought is a natural phenomenon of many aquatic ecosystems and insect species have evolved behavioural, morphological and life history traits to ensure persistence in intermittent habitats. Anthropogenic impacts like climate change or water abstraction alter hydrological regimes leading to increased frequency and decreasing predictability of droughts. The limnephilid caddisfly Micropterna lateralis is adapted to intermittent streams through adult diapause. However, annual variation in the onset of drying can result in larvae being exposed to drought. The molecular and physiological mechanisms driving this survival ability have not been studied to date. We performed common garden experiments to simulate drought for comparison of transcriptome-wide gene expression profiles under three hydrological conditions: wet, moist and dry. In total, we sequenced 18 larvae using Illumina-based Massive Analysis of cDNA Ends (MACE). Under drought stress, genes whose transcript levels decreased in response to hydrological change were dominant and primarily related to energy production, metabolism, translational processes, transport and cuticle components. Our study contributes to understanding the ability of species to react to projected environmental changes.

Felicitas Hoppeler (Primary Presenter/Author), Senckenberg Biodiversity and Climate Research Centre, felicitas.hoppeler@senckenberg.de;


Steffen Pauls ( Co-Presenter/Co-Author), Senckenberg Research Institute and Natural History Museum, Frankfurt, Germany, steffen.pauls@senckenberg.de;


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16:15 - 16:30: / 307 TROUT REVERSE THE EFFECT OF WATER TEMPERATURE ON THE FORAGING OF A MAYFLY

5/23/2016  |   16:15 - 16:30   |  307

TROUT REVERSE THE EFFECT OF WATER TEMPERATURE ON THE FORAGING OF A MAYFLY Climate change is likely to increase the metabolisms of ectothermic animals living below their thermal optimum. While ectothermic predators may compensate by increasing foraging, ectothermic prey may not because of increased predation risk from ectothermic predators. We examined how the diurnal drift behavior (foraging) of the mayfly Baetis, an ectothermic herbivore, responds to changing temperature in the implied presence and absence of trout, an ectothermic predator. In an experiment replicated at the catchment scale, water temperature and trout presence strongly interacted to affect the diurnal drift of Baetis from artificial channels lacking periphyton over a water temperature range of 4.2–14.8 °C. In fishless streams, daytime drift increased with increasing water temperature, likely because of increased metabolic demand for food. However, in trout-bearing streams, daytime drift decreased with increasing water temperature. Our interpretation is that the perceived threat of trout rose with increasing water temperature, causing mayflies to reduce foraging despite heightened metabolic demand. These results suggest that anticipated increases in stream temperature due to climate change may further escalate divergence in structure and process between fishless and trout-bearing streams.

Bruce Hammock (Primary Presenter/Author), University of California, Davis, brucehammock@gmail.com;


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16:30 - 16:45: / 307 CLIMATE CHANGE COULD INCREASE MAYFLY LIFE-HISTORY MISMATCH BETWEEN RUNOFF- AND GROUNDWATER-DOMINATED ALPINE STREAMS.

5/23/2016  |   16:30 - 16:45   |  307

CLIMATE CHANGE COULD INCREASE MAYFLY LIFE-HISTORY MISMATCH BETWEEN RUNOFF- AND GROUNDWATER-DOMINATED ALPINE STREAMS. In alpine streams, climate change is amplifying temperature and flow extremes, particularly in streams dominated by runoff (RO) from meltwater and/or precipitation. Conversely, groundwater-fed (GW) streams are expected to remain relatively stable. Temperature and flow regime influence life-history traits of aquatic insects, and increasing differences between stream types could drive greater life-history mismatch and potential reproductive isolation between RO/GW populations. To test this hypothesis, we collected and measured Andesiops peruvianus (Ephemeroptera) individuals at regular intervals for a year in 5 pairs of RO/GW streams, each at ca. 4000 m asl on two glaciated volcanoes in the Ecuadorian Andes. Across the pairs, RO streams had different degrees of temperature and flow variability. Early results suggest that A. peruvianus size distributions, emergence timing, and size at emergence diverge more between streams in pairs containing more variable RO streams. Assuming these spatial patterns of hydrologic variability can translate to temporal shifts associated with climate change, we predict increasing life-history divergence between alpine stream types. But whether this increasing mismatch will result in reproductive isolation will probably depend also on strength of seasonality.

Debra Finn (Primary Presenter/Author), Missouri State University, dfinn@missouristate.edu;


Henrietta Hampel ( Co-Presenter/Co-Author), University of Cuenca, hennihampel@gmail.com;


Raúl Vázquez ( Co-Presenter/Co-Author), University of Cuenca, raulfvazquezz@yahoo.co.uk;


Andrea C. Encalada ( Co-Presenter/Co-Author), Instituto BIOSFERA, Universidad San Francisco de Quito, Cumbayá, Ecuador Biológicas y Ambientales, Universidad San Francisco de Quito, Cumbaya, Ecuador, aencalada@usfq.edu.ec;


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16:45 - 17:00: / 307 EXPERIMENTAL DROUGHT IN EASTERN SIERRA NEVADA STREAMS

5/23/2016  |   16:45 - 17:00   |  307

EXPERIMENTAL DROUGHT IN EASTERN SIERRA NEVADA STREAMS Climate models project less precipitation and a shift in precipitation timing in the Sierra Nevada of California, with implications for the functioning of instream food webs. We experimentally induced flow reductions over two summers (2014-2015) in nine experimental stream channels at the Sierra Nevada Aquatic Research Laboratory (SNARL) to study how drought will affect stream food web, community and trait structure. Incremental flow reductions of baseline to intermittent drying were established in a press-type flow perturbation. Channels with reduced flow showed decreasing discharge reduced total and EPT insect density, while DO and Chlorophyll-A appeared unaffected. Flow responses of insects appeared idiosyncratic across taxa and functional feeding groups. These results suggest that taxa-specific responses and life histories must be considered when examining responses to flow perturbation in montane streams.

Parsa Saffarinia (Primary Presenter/Author), University of California, Riverside, psaff001@ucr.edu;


Dave Herbst ( Co-Presenter/Co-Author), Sierra Nevada Aquatic Research Laboratory, University of California Santa Barbara, david.herbst@lifesci.ucsb.edu;


Bruce Medhurst ( Co-Presenter/Co-Author), Sierra Nevada Aquatic Research Laboratory, University of California Santa Barbara, rbmedhurst@ucsb.edu;


Kurt Anderson ( Co-Presenter/Co-Author), University of California, Riverside, kurt.anderson@ucr.edu;


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