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SFS Annual Meeting

Thursday, May 23, 2019
09:00 - 10:30

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09:00 - 09:15: / 250 AB HABITAT STABILITY DIFFERENTIALLY DRIVES MASS-LENGTH RELATIONSHIPS AND TROPHIC TRAITS ACROSS FUNCTIONAL FEEDING GROUPS IN THE ECUADORIAN ANDES

5/23/2019  |   09:00 - 09:15   |  250 AB

HABITAT STABILITY DIFFERENTIALLY DRIVES MASS-LENGTH RELATIONSHIPS AND TROPHIC TRAITS ACROSS FUNCTIONAL FEEDING GROUPS IN THE ECUADORIAN ANDES Individual traits and community-wide measures uncover community assembly mechanisms, although intraspecific variation may complicate these relationships. Specifically, trophic trait variation could influence mass-length relationships, as more flexible consumers may maintain their body condition across environmental gradients. In this work, we leverage the steep environmental gradients of the Ecuadorian Andes to identify the drivers of both mass-length relationships and trophic traits within and across functional feeding groups. Mass-length regressions were steeper at less stable streams for Andesiops mayflies (variation in slopes up to 76%) and hydrobiosid predatory caddisflies (variation in slopes up to 82%), but not for Baetodes mayflies, filter-feeding blackflies or for hydropsychid generalist caddisflies. C:N of all five taxonomic groups was not driven by environmental variables, with higher variation within than among taxa. However, %C decreased with elevation for predatory caddisflies (Hydrobiosidae) and increased with elevation in generalist caddisflies (Hydropsychidae). Community-wide isotopic nestedness was low among all five taxa and did not vary along environmental gradients. This flexibility in both their trophic traits and mass-length relationships along elevation and stability gradients suggests that trait plasticity could play a crucial role in stream insect responses to changing environmental conditions.

Erin Larson (Primary Presenter/Author), Cornell University, ern.larson@gmail.com;


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;


Nicholas Hudson (Co-Presenter/Co-Author), Cornell University, nlh44@cornell.edu ;


Alexander Flecker (Co-Presenter/Co-Author), Cornell University, Ithaca, NY, USA, asf3@cornell.edu;


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09:15 - 09:30: / 250 AB WHERE TO GO FROM HERE? AQUATIC INSECT FUNCTIONAL AND TAXONOMIC DIVERSITY RESPOND TO CHANGES IN CANOPY, ELEVATION AND WATER TEMPERATURE IN ROCKY MOUNTAIN STREAMS

5/23/2019  |   09:15 - 09:30   |  250 AB

WHERE TO GO FROM HERE? AQUATIC INSECT FUNCTIONAL AND TAXONOMIC DIVERSITY RESPOND TO CHANGES IN CANOPY, ELEVATION AND WATER TEMPERATURE IN ROCKY MOUNTAIN STREAMS Growing levels of human-induced changes on mountainous streams around the globe, demand for an understanding of how species diversity and ecosystem function are affected by increasing water temperature and loss of riparian coverage along environmental gradients. Organismal traits determine how species perform and contribute to ecosystem functioning. Functional diversity quantifies the value and range of these traits, which provides a mechanistic framework to understand community productivity and resilience to perturbations or invasion. We applied a multifaceted framework to quantify functional diversity of stream insects along gradients of canopy coverage, water temperature and elevation across the Rocky Mountain Streams of Colorado. Our results showed that organismal traits related to development, habit, voltinism, and adult dispersal ability are highly correlated to environmental fluctuations, particularly to water temperature changes over 1°C in areas with an open canopy (less than 60% coverage). These findings support the understanding that small tributary streams collectively exhibit high beta diversity; and that taxonomic and functional richness declines with elevation in headwater mountain streams. Habitat heterogeneity, changes in water temperature, and increased pressure on dispersal traits between isolated communities; contribute to sustaining large biotic heterogeneity among small montane streams.

Rachel Harrington (Co-Presenter/Co-Author), ORISE/USEPA, harrington.rachel@epa.gov;


Boris Kondratieff (Co-Presenter/Co-Author), Colorado State University, Boris.Kondratieff@ColoState.edu;


Colleen Webb (Co-Presenter/Co-Author), Colorado State University, Colleen.Webb@colostate.edu;


Cameron Ghalambor (Co-Presenter/Co-Author), Colorado State University, cameron.ghalambor@colostate.edu;


LeRoy Poff (Co-Presenter/Co-Author), Colorado State University, n.poff@rams.colostate.edu;


Carolina Gutierrez (Primary Presenter/Author), Colorado State University, cgcol@rams.colostate.edu;


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09:30 - 09:45: / 250 AB ICY SEEPS: A POTENTIAL STRONGHOLD FOR ALGAL STENOTHERM BIODIVERSITY

5/23/2019  |   09:30 - 09:45   |  250 AB

ICY SEEPS: A POTENTIAL STRONGHOLD FOR ALGAL STENOTHERM BIODIVERSITY A warming climate and melting glaciers are likely to have impacts on alpine streams with potential loss of cold stenotherm biodiversity and ecosystem function. Streams that originate from subterranean ice termed “icy seeps” with constant, cold flows, may provide refugia for taxa as temperatures rise. Compared to glacier-fed streams, icy seeps also have higher conductivity and lower turbidity. This research is focused on understanding the role of hydrological sources in shaping algal assemblages in alpine headwaters, focusing on icy seeps as cold water refugia. Epilithic samples were collected from streams in the Teton Range, Wyoming with source water from glaciers, snowmelt, or icy seeps. Algal communities in snowmelt streams had taxa typical of high-elevation ecosystems (diatoms Hannaea arcus, Odontidium mesodon) while glacial streams had algal communities with lower diversity. Communities from icy seeps had higher diversity, dominated by upright diatoms (Gomphonema spp., Synedra spp.) and cyanobacterium Oscillatoria. Both glacier-fed streams and icy seeps had nitrogen-fixing taxa (diatom Epithemia sorex), indicating potential nitrogen limitation, compared to snowmelt streams. Because of their subterranean source and functional algal assemblages, icy seeps show potential as coldwater refugia as glaciers disappear.

Rebecca Bixby (Primary Presenter/Author), University of New Mexico, bbixby@unm.edu;


Monika Hobbs (Co-Presenter/Co-Author), University of New Mexico, mohobbs@unm.edu;


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


Lusha Tronstad (Co-Presenter/Co-Author), University of Wyoming, Wyoming Natural Diversity Database, tronstad@uwyo.edu;


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09:45 - 10:00: / 250 AB AN EXPERIMENTAL TEST OF CLIMATE DRIVEN CHANGES IN STREAM TEMPERATURE, LIGHT, AND NUTRIENT AVAILABILITY ON BIOFILMS AND NUTRIENT DYNAMICS

5/23/2019  |   09:45 - 10:00   |  250 AB

AN EXPERIMENTAL TEST OF CLIMATE DRIVEN CHANGES IN STREAM TEMPERATURE, LIGHT, AND NUTRIENT AVAILABILITY ON BIOFILMS AND NUTRIENT DYNAMICS Understanding how environmental conditions such as streamwater temperature, light, and nutrient availability act as mechanistic drivers of stream biofilm development is critical to understanding how climate driven changes in these conditions could affect stream food webs and river biogeochemistry. Biofilm availability and elemental resource quality are critical for invertebrate consumers, and biofilms also drive whole-river nutrient cycling through uptake and internal cycling. Biofilms in high elevation streams are already subject to changing environmental conditions because snowmelt is advancing rapidly. Therefore, we manipulated light, temperature, and nutrient availability in two experiments conducted in flow-through stream channels at 2896 m to determine how these factors influence the seasonal trajectory of biofilm biomass, resource quality (e.g., %P, %N), and nutrient uptake (NH4-N, NO3-N, PO4-P). Preliminary analyses show that warm, low-light conditions (favoring bacteria) reduced biofilm biomass and increased %P relative to ambient conditions across the season; whereas, a nutrient pulse temporarily increased algal biomass and %P. Warming accelerated phosphorus and ammonium uptake, but not nitrate, consistent with predicted shifts towards bacterial communities. Our results suggest that following early snowmelt, warm and turbid streams could develop high resource quality biofilms dominated by bacteria.

Brad Taylor (Co-Presenter/Co-Author), North Carolina State University Dept. of Applied Ecology; Rocky Mountain Biological Laboratory, bwtaylo3@ncsu.edu ;


Jared Balik (Primary Presenter/Author), North Carolina State University, Rocky Mountain Biological Laboratory, jabalik2@ncsu.edu;


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10:00 - 10:15: / 250 AB BENTHIC PRIMARY PRODUCTION IN MOUNTAIN LAKES: GRADIENTS VERSUS LOCAL FACTORS

5/23/2019  |   10:00 - 10:15   |  250 AB

BENTHIC PRIMARY PRODUCTION IN MOUNTAIN LAKES: GRADIENTS VERSUS LOCAL FACTORS Mountain lakes exist along strong environmental gradients, yet local mosaic factors may modify the effects of these environmental gradients on within-lake processes. In particular, the impacts of climate change may be modified by local factors in unpredictable ways, which may disrupt the functioning of these high elevation climate refugia. We tested the influence of localized mosaic factors and large-scale gradients on benthic primary productivity in 12 lakes across two mountain ranges, the Cascade and Olympic Mountains. Lakes ranged in elevation (1300-1640 m), surface area (<1-18 ha), maximum depth (4-18 m), and catchment slope (5-62%). At each lake, we chose rocks of uniform size and incubated them in light and dark chambers for two hours at peak sunlight. Oxygen sensors were placed inside the chambers to measure dissolved oxygen concentrations either over the entire experiment duration or at the beginning and end. We found that benthic primary productivity was affected by a combination of large-scale gradient factors, such as elevation and temperature, and localized variation, such as catchment properties. Understanding how ecosystem processes in mountain systems are affected by climate will be critical for the future.

Angela Strecker (Primary Presenter/Author), Portland State University, strecker@pdx.edu;


Ariana Chiapella (Co-Presenter/Co-Author), Portland State University, ac23@pdx.edu;


Steven Fradkin (Co-Presenter/Co-Author), National Parks Service, steven_fradkin@nps.gov;


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