5/22/2016  |   10:30 - 10:45   |  302-303

CONTEMPORARY THERMAL ADAPTATION OF A PREDATOR EXACERBATES ECOLOGICAL CONSEQUENCES OF CLIMATE WARMING Evolutionary responses to thermal conditions occur on timescales contemporary with ecological processes, yet empirical work testing their relevance is lacking. We tested whether rapid evolutionary thermal adaptation in a potent freshwater predator, western mosquitofish (Gambusia affinis), has ecological effects, and asked whether those effects dampen or exacerbate the consequences of warming. Specifically, we used two recently divergent (<100 years) mosquitofish populations (a warm-source and a cool-source) to test for evidence of thermal adaptation, and then tested for divergence in ecological effects in ambient and warmed (+2 C) ponds. F2 fish showed trait divergence consistent with thermal adaptation; warm-source fish grew slower and were relatively smaller at maturity. In experimental ponds, warm-source fish caused a relatively greater reduction in zooplankton biomass and induced a greater shift towards small-bodied taxa. Pond warming resulted in similar effects for zooplankton as did thermal adaptation. These results suggest contemporary thermal adaptation in predators may be an important pathway by which warming can have ecological implications. Particularly, they suggest that rapid predator thermal adaptation may exacerbate warming-induced prey community body size reduction, possibly having cascading consequences.

David Fryxell (Primary Presenter/Author), University of California - Santa Cruz, dcfryxell@gmail.com;


Eric Palkovacs ( Co-Presenter/Co-Author), University of California - Santa Cruz, epalkova@ucsc.edu;


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5/22/2016  |   10:45 - 11:00   |  302-303

SOME LIKE IT HOT: INTRASPECIFIC VARIATION IN CONSUMER METABOLISM AND NUTRIENT EXCRETION DRIVEN BY TEMPERATURE Consumers influence energy and nutrient cycling in freshwaters through energy demand and nutrient excretion. Temperature and body size are key factors driving metabolism and excretion, presumably following metabolic theory (MTE) scaling rules. However, it is not clear if adaptation can lead to deviation from MTE predictions. We used mosquitofish (Gambusia affinis), a globally invasive fish, to examine divergence in size/temperature scaling of metabolism and nutrient excretion among populations invading systems varying widely in temperature (19-30°C). In a set of parallel spring-fed systems of varying geothermal influence in New Zealand and California, we measured in situ metabolic rates and nitrogen excretion of individuals ranging in body size. Across all individuals, metabolism scaled with body size with slope ~0.75, following MTE. However, allometric slopes of individual populations ranged ~0.7-0.8 and increased with temperature. Surprisingly, size-corrected rates of metabolism were unrelated to temperature. Scaling of excretion was much more variable (slopes 0.4-0.9) and did not track temperature. Overall, our data suggest considerable adaptive flexibility to temperature and potential decoupling of consumer energy demand and nutrient recycling in the face of changing temperature.

Emma Moffett (Primary Presenter/Author), The University of Auckland, emma.moffett@auckland.ac.nz;


David Fryxell ( Co-Presenter/Co-Author), University of California - Santa Cruz, dcfryxell@gmail.com;


Kevin Simon ( Co-Presenter/Co-Author), The University of Auckland, k.simon@auckland.ac.nz;


Eric Palkovacs ( Co-Presenter/Co-Author), University of California - Santa Cruz, epalkova@ucsc.edu;


Michael Kinnison ( Co-Presenter/Co-Author), University of Maine, mkinnison@maine.edu;


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5/22/2016  |   11:00 - 11:15   |  302-303

EFFECTS OF DROUGHT ON NON-SEASONAL RAINFOREST STREAMS The driest years on record in 1994 and 2015 caused non-seasonal, rainforest headwaters at El Verde, Puerto Rico to have a pulsed input of leaf litter that accumulated on surrounding surfaces until the first high rainfall event transported large inputs of litter to the stream channel. In 2015 several months of prolonged dryness caused increased inputs of leaf litter, declines in flow, low water quality, and changes in densities of the dominant consumers. Low flows altered upstream migrations of the largest shrimp predators (Macrobrachium carcinus and Macrobrachium crenulatum) and smaller shrimp (Atya lanipes and Xiphocaris ellongata) that function as detrivores and grazers. The community remains resilient although an increased frequency in drought or a shift in annual distributions of rainfall, as currently predicted for the Caribbean, could alter dominance and result in establishment of new species. These drought effects are stronger and more persistent than previously observed disturbances created by two hurricanes (1988, 1998) and Tropical Storm Erika in August 2015.

Alan Covich (POC,Primary Presenter), Odum School of Ecology, University of Georgia, a.covich@gmail.com;


Todd Crowl ( Co-Presenter/Co-Author), Florida International University, facrowl@gmail.com;


Omar Perez-Reyes ( Co-Presenter/Co-Author), University of Puerto Rico- Rio Piedras, macrobrachium@gmail.com;


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5/22/2016  |   11:15 - 11:30   |  302-303

EQUATORIAL PRO-GLACIAL LAKES: ARE THEY DIFFERENT FROM THEIR HIGHER LATITUDE HOMOLOGUES? Due to glacial retreat, the number of pro-glacial lakes is currently growing worldwide. The relatively few studies that have been performed on the ecology of this dynamic lake type are from arctic-temperate latitudes, and reveal biologically very poor ecosystems due to environmental harshness. Hitherto, virtually nothing is known about proglacial lakes in the tropics. They are generally not exposed to ice-cover, but to extreme UV radiation and low oxygen availability at very high altitude. Here we present the results of a survey of a number of proglacial lakes in Ecuador. We were especially interested in the pelagic versus benthic biomass and biodiversity along a gradient in turbidity from suspended “glacial flour” (fine mineral particles) as an expected environmental key factor. Biological features of the equatorial pro-glacial lakes did, however, not seem to be greatly determined by turbidity, as even clear lakes with only indirect glacial influence were very poor. Factors related to the extreme altitude seem to be more important in structuring the biological structure of these lakes.

Dean Jacobsen (Primary Presenter/Author), Freshwater Biological Laboratory, University of Copenhagen, Denmark, djacobsen@bio.ku.dk;


Kirsten Seestern Christoffersen ( Co-Presenter/Co-Author), Freshwater Biological Laboratory, University of Copenhagen, Depth of Arctic Biology, University Center in Svalbard, Norway, kchristoffersen@bio.ku.dk;


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5/22/2016  |   11:30 - 11:45   |  302-303

THE COMBINED EFFECTS OF CLIMATE CHANGE AND NON-NATIVE SPECIES ON SOUTHERN ROCKY MOUNTAIN CUTTHROAT TROUT Climate change is altering where aquatic populations occur on the landscape and within river networks, through shifting thermal and hydrological regimes. However, within the southern Rocky Mountains native trout are also threatened by non-native trout invasions. We used a combination of stream temperature modeling, detailed distribution databases, Bayesian Network models, and simulations of trout invasions to analyze the combined effects of climate change and non-native trout on two native trout (Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus, and Rio Grande Cutthroat Trout O. c. virginalis). We found warming stream temperatures a detriment to some of these populations, but that past habitat fragmentation and projected non-native trout invasions have a greater chance of extirpating populations. For example, our simulation predicts, without management intervention, that 39% of Colorado River Cutthroat Trout populations (N=122) will be extirpated by invasions by 2080, compared with only one owing to climate change alone. These results indicate that both emerging (e.g., climate change) and well known (e.g., non-native) threats to native species conservation must be considered when allocating research and management resources.

James J. Roberts (Primary Presenter/Author), U.S. Geological Survey, Ann Arbor, MI 48105, jroberts@usgs.gov;


Kurt D. Fausch ( Co-Presenter/Co-Author), Colorado State University, Department of Fish, Wildlife, and Conservation Biology, Fort Collins, CO 80523, Kurt.Fausch@colostate.edu;


Mattew P. Zeigler ( Co-Presenter/Co-Author), New Mexico Department of Game and Fish, Santa Fe, NM 87507, Matthew.Zeigler@state.nm.us;


Kevin B. Rogers ( Co-Presenter/Co-Author), Colorado Parks and Wildlife, Steamboat Springs, CO 80477, kevin.rogers@state.co.us;


Andrew S. Todd ( Co-Presenter/Co-Author), U. S. Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver, CO 80225, atodd@usgs.gov;


Douglas P. Peterson ( Co-Presenter/Co-Author), U. S. Fish and Wildlife Service, Abernathy Fish Technology Center, Longview, WA 98632, doug_peterson@fws.gov;


Mevin B. Hooten ( Co-Presenter/Co-Author), U. S. Geological Survey, Colorado Cooperative Fish and Wildlife Research Unit, Fort Collins, CO 80523, hooten@rams.colostate.edu;


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5/22/2016  |   11:45 - 12:00   |  302-303

PREDICTED CLIMATE DRIVEN CHANGES IN FLOW AFFECT STREAM NUTRIENT DYNAMICS IN HAWAII Climate-driven changes in rainfall are predicted to decrease flow and increase flash flooding in tropical freshwater ecosystems, but the ecological implications of these changes are poorly understood. We measured excretion rates of three dominant invertebrates and quantified stream nutrient (i.e. nitrogen (N), phosphorus (P)) demand in seven streams across a 4500 mm/yr rainfall gradient along the North Hilo region of Hawaii Island. The demand for N and P ranged between 0.39 – 3.74 mg N/m²/hr and 0.06 – 4.26 mg P/m²/hr, and was highest in medium flow streams. Midges and caddisflies had 2-4x lower mass-specific nitrogen excretion rates in drier streams, while phosphorous excretion rates did not vary along the gradient. The total concentrations of nutrients recycled by consumers decreased across the gradient because invertebrate densities declined. We conclude that predicted climate driven changes in flow will significantly decrease the total amount of nutrients exported by these streams, which can have a substantial effect on the productivity of organisms at the base of food webs (e.g. microbes, algae) in downstream and near-shore habitats.

Therese C. Frauendorf (Primary Presenter/Author), University of Victoria, tfrauend@uvic.ca;


Richard MacKenzie ( Co-Presenter/Co-Author), USDA Forest Service, rmackenzie@fs.fed.us;


Rana El-Sabaawi ( Co-Presenter/Co-Author), University of Victoria, rana@uvic.ca;


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