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

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15:30 - 15:45: / 314 ASSESSING THE LONG-TERM RESPONSE OF HEADWATER STREAM CONDITIONS TO RIPARIAN MANAGEMENT PRACTICES

5/23/2016  |   15:30 - 15:45   |  314

ASSESSING THE LONG-TERM RESPONSE OF HEADWATER STREAM CONDITIONS TO RIPARIAN MANAGEMENT PRACTICES Forested watersheds are under increasing logging pressure worldwide. Despite accumulating research on forestry impacts on headwater stream ecosystems, few studies have tracked their long-term recovery. However, understanding recovery patterns is vital for setting targets for watershed management. A 2006 study adopted a multi-watershed, replicated design to investigate how various forestry practices affected stream organic matter dynamics in a Canadian coastal temperate rainforest. It was conducted 8 years after riparian clear-cutting with differences in fixed-width streamside reserves (0 m, 10 m and 30 m), and 1 year after thinning (50% tree removal). Streams in logged catchments generally supported lower litter decomposition rate and shredder density, but similar rarefied shredder richness, relative to reference sites. Similar physical and biological attributes were re-measured in 2013. After an additional 7-year forest regeneration, decomposition rate and shredder density in logging-impacted streams converged with values in reference sites. Stream functional integrity improved considerably across forestry practices, likely at a faster rate in reaches with adjacent thinning than clear-cut logging with or without reserves. Our findings could inform forest management with approximate time scales towards post-logging ecological recovery.

Alex Yeung (Primary Presenter/Author), Department of Forest and Conservation Sciences, University of British Columbia, Canada, yeungcheeyu@gmail.com;


Antoine Lecerf ( Co-Presenter/Co-Author), EcoLab, Université de Toulouse, CNRS, France, antoine.lecerf@univ-tlse3.fr;


John Richardson ( Co-Presenter/Co-Author), Department of Forest and Conservation Sciences, University of British Columbia, john.richardson@ubc.ca;


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15:45 - 16:00: / 314 THE EFFECT OF RIPARIAN DISTURBANCE ON THE HABITAT, SUMMER DIET, AND CONDITION OF AGE-0 BROOK TROUT (SALVELINUS FONTINALIS) IN CENTRAL APPALACHIAN STREAMS

5/23/2016  |   15:45 - 16:00   |  314

THE EFFECT OF RIPARIAN DISTURBANCE ON THE HABITAT, SUMMER DIET, AND CONDITION OF AGE-0 BROOK TROUT (SALVELINUS FONTINALIS) IN CENTRAL APPALACHIAN STREAMS Human activities have caused brook trout populations to decrease across most of their range. Brook trout, the only native salmonid in central Appalachia, are an integral part of stream ecology and an important source of tourism revenue. This study examined how intense, small-scale riparian disturbance affected the habitat, diet, and condition of age-0 brook trout. Riparian trees were harvested at 50% and 90% basal area harvest on 8 central Appalachian streams, with some stream sections receiving woody debris additions. Disturbed stream sections were compared to upstream reference sections. While small-scale riparian disturbance had little effect on stream sedimentation and turbidity, significant changes were observed in stream morphology, temperature, primary productivity, and terrestrial invertebrate inputs. Limited effects on aquatic invertebrates were observed. Within three of these streams, the weights, lengths, and stomach contents of 663 age-0 brook trout were collected. Riparian disturbance significantly affected the diet and condition of age-0 brook trout, however the response to disturbance was not consistent between streams and was likely modified by other factors such as temperature and alkalinity.

Jered Studinski (Primary Presenter/Author), Frostburg State University, jmstudinski@frostburg.edu;


Andrew Hafs ( Co-Presenter/Co-Author), Bemidji State University, AHafs@bemidjistate.edu;


Kyle Hartman ( Co-Presenter/Co-Author), West Virginia University, kyle.hartman@mail.wvu.edu;


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16:00 - 16:15: / 314 SEDIMENTATION, HABITAT LOSS AND CONNECTIVITY AS DRIVERS OF STREAM COMMUNITIES AND ECOSYSTEM PROCESSES: IMPLICATIONS FOR STREAM RESTORATION

5/23/2016  |   16:00 - 16:15   |  314

SEDIMENTATION, HABITAT LOSS AND CONNECTIVITY AS DRIVERS OF STREAM COMMUNITIES AND ECOSYSTEM PROCESSES: IMPLICATIONS FOR STREAM RESTORATION Habitat degradation is one of the leading causes of biodiversity loss, and land-use induced sedimentation causes severe habitat impairment in streams. Restoration attempts to improve in-stream habitats but reduced connectivity to source areas may obscure any positive effects of restoration. In a mesocosm experiment, we assessed the independent and interactive effects of sedimentation, habitat (macrophyte) loss and connectivity on benthic invertebrate communities and ecosystem processes (periphyton production; leaf decomposition). Enhanced dispersal increased benthic abundances but only in the presence of macrophytes. Invertebrate community dominance was also higher in streams with macrophytes. The standing stock of FPOM was on average five times, and that of CPOM three times, higher in streams with than without macrophytes. Correspondingly, leaf breakdown rate was significantly lower in the presence of macrophytes. Sedimentation reduced algal biomass but had little effect on leaf decomposition. Macrophytes constitute a strong habitat filter in boreal streams with distinct communities in streams with vs. without macrophytes. They also modify ecosystem functions, particularly organic matter retention and decomposition. Restoration projects therefore need to acknowledge the importance of macrophytes to stream ecosystem recovery.

Timo Muotka (Primary Presenter/Author), Ecology and Genetics Research Unit, University of Oulu, Finland, timo.muotka@oulu.fi;


Jukka Aroviita ( Co-Presenter/Co-Author), Finnish Environment Institute (Syke), jukka.aroviita@ymparisto.fi;


Pauliina Louhi ( Co-Presenter/Co-Author), Natural Resources Institute Finland, pauliina.louhi@luke.fi;


Heikki Mykrä ( Co-Presenter/Co-Author), University of Oulu, heikki.mykra@oulu.fi;


Emmi Putkonen ( Co-Presenter/Co-Author), University of Oulu, emmi.putkonen@student.oulu.fi;


Jarno Turunen ( Co-Presenter/Co-Author), Finnish Environment Institute, jarno.turunen@ymparisto.fi;


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16:15 - 16:30: / 314 THE INFLUENCE OF FOREST MANAGEMENT AND NATURAL DISTURBANCE ON LOTIC FOOD WEBS

5/23/2016  |   16:15 - 16:30   |  314

THE INFLUENCE OF FOREST MANAGEMENT AND NATURAL DISTURBANCE ON LOTIC FOOD WEBS A variety of anthropogenic (logging, road building, climate change) and natural disturbances (e.g., debris flows) influence the flow of energy and matter in forest streams in complex ways. For example, climate change has increased the size, frequency, and intensity of wildfires, which then impact streams and their food webs by increasing sediment and organic matter inputs while simultaneously opening the canopy. Elucidating the causes and ecological consequences of current and predicted changes in the disturbance regime is a major challenge for the management of forest streams. We briefly examine three studies in forest streams to address some of consequences of multiple disturbance types on stream food webs and highlight some of key challenges for future studies. These studies include a before-after riparian buffer width study in headwater streams of British Columbia, Canada; a multi-stream study comparing the effects of logging, fire and beetle infestation on headwater streams of the Okanagan region of south-central British Columbia; and a long-term study of salmon recolonization in 2nd growth forest streams of western Washington, USA.

Peter Kiffney (Primary Presenter/Author), Northwest Fisheries Science Center, peter.kiffney@noaa.gov;


John Richardson ( Co-Presenter/Co-Author), Department of Forest and Conservation Sciences, University of British Columbia, john.richardson@ubc.ca;


Adam Goodwin ( Co-Presenter/Co-Author), Consulting, goodwin.ab@gmail.com;


Adam Wei ( Co-Presenter/Co-Author), University of British Columbia, adam.wei@ucb.ca;


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16:30 - 16:45: / 314 PHYSIOLOGICAL RESPONSES OF FRESHWATER CONSUMERS TO VARIATIONS OF THE DURATION AND INTENSITY OF THE STOICHIOMETRIC IMBALANCE WITH THE RESOURCE

5/23/2016  |   16:30 - 16:45   |  314

PHYSIOLOGICAL RESPONSES OF FRESHWATER CONSUMERS TO VARIATIONS OF THE DURATION AND INTENSITY OF THE STOICHIOMETRIC IMBALANCE WITH THE RESOURCE As input rates of resources of different quality from the terrestrial environments show a strong seasonality, the overall negative effect of land use changes might be the resultant of very short but intense stoichiometric imbalances. The biota responds to these imbalances with physiological changes, although we need more knowledge about the relationship between the effect size of easy-to-measure and ecologically meaningful physiological variables and the intensity and duration of the imbalances. In this context, we performed an experiment in which we subject the amphipod Echinogammarus berilloni (Catta) to a gradient of food quality (alder, ash, chestnut, oak and beech discs). After 2, 4, 8, 16 and 32 days of incubation we measured the RNA:DNA ratio, lipid content, body mass condition and the growth rate of the consumer, and the consumption rate of resources. The biological responses obtained in this kind of experiments can be used to fence critically stressful seasons in freshwater ecosystems facing land use changes.

Aitor Larrañaga (Primary Presenter/Author), University of the Basque Country (UPV/EHU), aitor.larranagaa@ehu.eus;


Libe Solagaistua ( Co-Presenter/Co-Author), University of the Basque Country (UPV/EHU), libe.solagaistua@ehu.eus;


Arturo Elosegi ( Co-Presenter/Co-Author), University of the Basque Country (UPV/EHU), arturo.elosegi@ehu.eus;


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16:45 - 17:00: / 314 ISOTOPIC VARIATION OF BASAL RESOURCES AND DEGRADATION OF STREAM ECOSYSTEMS THROUGH LAND-USE INTENSIFICATION

5/23/2016  |   16:45 - 17:00   |  314

ISOTOPIC VARIATION OF BASAL RESOURCES AND DEGRADATION OF STREAM ECOSYSTEMS THROUGH LAND-USE INTENSIFICATION Land-cover changes associated with agriculture and urbanization alter nutrient supply, allochthonous inputs, autochthonous production, and the quality and quantity of available food resources in streams, potentially influencing trophic food webs and biodiversity. Although many studies have used isotope analysis to quantify general responses to land-use, few have explicitly examined how this variation is related with the quantity and quality of basal-resources that support food webs. We combined quantitative sampling of resources and consumers, and naturally occurring stable isotopes of C and N, to investigate how land-use affects basal-resources (seston, FPOM, periphyton, leaf litter) in nine streams located in British Columbia (Canada). Land-use was an important factor explaining the overall degradation of streams, as well as the variability in basal-resource signatures. Mean ?15N of all basal-resources in urban and agricultural streams was 1.6 to 2.8 times higher than that of forested streams, and was correlated with deterioration of water quality and loss of biodiversity. Our results highlight the need to assess land use-driven changes in basal-resource characteristics for understanding trophic transfer rates and potential changes to nutrient cycling in food webs.

Liliana Garcia (Primary Presenter/Author), Universidade de Vigo, lilizar@uvigo.es;


Wyatt Cross ( Co-Presenter/Co-Author), Montana State University, wyatt.cross@montana.edu ;


Isabel Pardo ( Co-Presenter/Co-Author), Universidade de Vigo, ipardo@uvigo.es;


John Richardson ( Co-Presenter/Co-Author), Department of Forest and Conservation Sciences, University of British Columbia, john.richardson@ubc.ca;


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