Title: Diverse undergraduate student experiences of future freshwater scientists

S01: Future Freshwater Scientists - UNDERGRADS

Coordinator: Matt Cover (mcover@csustan.edu)

Much has been written about the need to diversify STEM fields, especially ecology and environmental science. Most professional scientific societies, SFS included, have programs to support and expand opportunities for undergraduate students. However, attendees at SFS meetings tend to primarily include faculty, professionals, and graduate students from R1 universities and federal agencies. To broaden participation in our discipline, we need to consider the experience of undergraduate students at a wide range of institutions, including primarily undergraduate institutions such as community colleges, state colleges, and liberal arts colleges. What opportunities, experiences, and difficulties face students in these settings? How does the undergraduate experience of these students compare to those of the membership of SFS, and what can we learn from these experiences that will help us, as a society, to be more inclusive? What experiences are most important in the career development of future freshwater scientists? In this session we will hear from educators and students from a wide range of higher education institutions. This session will be unique in that in will conclude with a 30-minute panel discussion, in which college faculty and educators share the stage with their students. We will begin with six 15-minute sessions that each include a brief (~8 minute) presentation by a faculty member about their own experiences as an educator working with a diverse student body. The speaker will then pose one or more questions to the panel to allow a dialogue about faculty and student experiences with curriculum, mentorship, research, and other aspects of the undergraduate student experience. Students and faculty will share the key educational experiences and challenges that have had an impact on their career choices and trajectory. Attendees will leave the session with a better appreciation of the importance of curriculum, programs, and undergraduate experiences that are important for our discipline to broaden participation and diversify membership.

Note: Participants in this session are permitted to submit one additional abstract to a different session.

Title: Climate and drought effects on mountain stream ecosystems

S02: Climate and Drought Effects on Mountain Stream Ecosystems

Organizer: Dave Herbst (david.herbst@lifesci.ucsb.edu)

Climate change induced extremes in precipitation and runoff are becoming pronounced as warming temperatures, drought, forest wildfires, and floods have altered the hydrologic environment, especially in the snowmelt-driven flows of mountain stream ecosystems. In temperate mountain regions of the world (including the Sierra Nevada of California) climate has undergone extended severe droughts along with atmospheric river storms and such extremes are forecast to become even more prevalent in the future. This session provides a forum for discussing observations and experiments related to these climate-driven effects, with focus on altered hydrology and thermal regimes linked to effects on community ecology, loss of biodiversity values of montane streams, and shifting context for the natural range of variation that gives insight to what the future may bring.

Title: Global perspectives on evaluating and managing environmental flows under increasing levels of scarcity and uncertainty

S03: Global Perspectives on Environmental Flows

Organizers: Jonathan Kennen, Eric Stein (erics@sccwrp.org), Angus Webb

Growing water demands coupled with recent droughts have produced increasingly widespread water scarcity in the West, Southwest, and Southeastern United States and in many arid and semi-arid regions throughout the world. These shortages emphasize that there are critical limits on the amount of water available to support human and ecological needs. Climate change exacerbates this issue because water managers, under increasing levels of uncertainty, need to develop adaptive strategies that minimize ecosystem vulnerability while maximizing water availability for human use. This uncertainly has led to legal confrontations among water users in the public and private sector and has motivated some State and Provincial governments to consider establishing environmental flow rules and criteria (e.g., instream or minimum flow requirements) for the protection of biological resources and ecosystem integrity. This Special Session will highlight ongoing research and collaboration on timely issues linking drought and environmental flow needs. This session will emphasize research and case studies on the development of decision support tools to help managers apply the results of hydroecological analyses, methods that establish environmental flow standards using multiple biological endpoints, estimates of environmental flow time series including advances in hydrologic modeling, and flow-alteration ecological response models that help managers, policy makers and environmental flow practitioners better understand how alterations in streamflow and increasing levels of water scarcity and uncertainty resulting from drought, climate change and anthropogenic processes affect the long-term viability and integrity of aquatic ecosystems.

Title: Temporary wetlands: Here today gone tomorrow

S04: Temporary Wetlands

Organizers: Brian O'Neill (oneillb@uww.edu), D. Christopher Rogers, Kelley Fritz

Temporary wetlands (such as vernal pools, playas, salt lakes, and rock pools) occur throughout much of the world. These habitats support unique assemblages of flora and fauna that are adapted to annual and/or sporadic wet-dry cycles. Many terrestrial organisms such as mammals, birds, reptiles, amphibians, and insects utilize temporary wetlands for a portion of their life cycle and/or forage in them, making these habitats essential components of landscapes. Additionally, wholly aquatic communities reside in temporary wetlands by employing a wide variety of strategies to overcome the dry phase of the hydrocycle. Temporary wetlands are closely connected to surrounding terrestrial habitats and food webs through exchange of energy and nutrients including biomass export of emerging aquatic insect and amphibian metamorphs. Small wetlands also play a critical role in metapopulation dynamics at the landscape scale. Due to their seasonal drying and often short hydroperiods, many temporary wetlands have been converted for agricultural and urbanization, leading to severe losses of temporary wetlands worldwide. Groundwater extraction has also altered the hydrology of temporary wetlands in some regions. Changing climate patterns are expected to have a drastic impact on some temporary wetlands that rely on a consistent annual wetting, yet may have little impact on wetlands that are sporadically inundated. These two aspects make temporary wetland research an important topic to study in times when water is becoming scarce in many areas. The goal of this session is to highlight the unique ecology of temporary wetlands and the threats posed by water scarcity to these dynamic ecosystems. This session would be of interest to a broad range of SFS members with interests in: wetland ecology, food webs, subsidies, aquatic-terrestrial linkages, adaptations, conservation biology, hydrology, climate change, and land-use changes.

Title: Eco-hydrology of intermittent rivers and ephemeral streams in the face of a changing climate

S05: Eco-hydrology of IRES in a Changing Climate

Organizers: Thibault Datry (Thibault.datry@irstea.fr), Dan Allen, Michael Bogan, Kristin Jaeger, Katie Costigan, Raphael Mazor

A large proportion of the global river network is composed of intermittent rivers and ephemeral streams (IRES). While IRES have been historically overlooked by freshwater scientists, growing interest in the past decade has led to a better understanding of their eco-hydrology and biodiversity. Growing evidence suggests that IRES contribute substantially to catchment-scale biodiversity and organic matter processing. From an ecosystem perspective, IRES alternate aquatic and terrestrial phases that are functionally linked, supporting diverse biotic communities and various biogeochemical processes. In addition, IRES provide important ecosystem services to human societies, such as groundwater recharge. In turn, IRES are now receiving increased attention from water resource managers. Due to climate change and increased freshwater demands, the relative proportion of IRES may be increasing in many regions. Once-perennial rivers are becoming artificially intermittent, and drying event frequency and duration in natural IRES are increasing. This special session will present the latest research on the eco-hydrology of IRES in the context of climate change and address potential challenges in managing these ecosystems.

Title: Incorporating molecular methods into routine biomonitoring-Charting a path forward.

S06: Molecular Methods in Biomonitoring

Organizers: Erik Pilgrim (pilgrim.erik@epa.gov), Eric Stein

In the past ten years, the use of molecular methods to support freshwater bioassessment & biomonitoring has moved beyond just a concept. Studies have shown that approaches such as DNA barcoding and metabarcoding can provide in depth and timely information that not only supports existing bioassessment approaches but helps to expand the scope and resolution of assessment tools. Despite the demonstrated utility of molecular genetic methods, there are few examples of these tools being integrated into routine and ongoing monitoring and assessment programs. A potential impediment to full implementation is the lack of agreed upon procedures, tolerances, and quality control measures that ensure the repeatability and certainty of the results of molecular-based bioassessment. This session will explore the latest process studies and demonstration projects aimed at answering critical questions such as minimal detectable limits of environmental DNA, residence time, repeatability, and development of standard bioinformatics and assessment tools. We hope to use this session to begin a dialogue about how critical information gaps can be filled in order to more easily move molecular methods from concept to practice.

Title: Challenges in freshwater conservation: A global perspective

S07: Challenges in Freshwater Conservation

Organizers: Alonso Ramírez (aramirez@ramirezlab.net), Blanca Ríos-Touma

Freshwater conservation issues are ever more important and diverse globally: Parts of North and South America are facing climate related issues, such as drought or more severe ENSO effects; salinization of many freshwater ecosystems of Mediterranean areas; glacier melting an temperature changes in alpine rivers; intensive single-species agricultural activities are expanding in many tropical countries with extensive use of toxic pesticides; invasive species in highly fragile freshwater ecosystems, urbanization continues to increase at a rapid pace in many regions in Asia; and many regions face serious lacks of basic infrastructure to deal with residual waters. Similarly diverse are the limitations that researchers and managers are facing when dealing with conservation issues. The International Coordination Committee proposes a special session to highlight the diversity of freshwater biodiversity conservation issues globally and the challenges that freshwater scientists are facing in different parts of the world, and the potential mitigation actions to protect freshwater biodiversity. The session will be open to all, but the ICC will be inviting speakers from different continents to participate. In addition to informing on conservation issues, the session will help us explore the role that SFS could play in supporting freshwater researchers in different countries.

Title: New approaches to assessing and predicting the impacts of hydroclimatic extremes of freshwater populations, communities, and ecosystems

S08: Hydroclimatic Extremes

Organizers: Albert Ruhi (albert.ruhi@asu.edu), John Kominoski, John Sabo

Climate-driven intensification of the global hydrologic cycle is increasing the frequency and magnitude of extreme events (droughts and floods) and this increasing environmental variability poses threats on biodiversity and ecosystem functioning. In lotic ecosystems, alterations to baseline discharge variation regimes may erode native biodiversity, affect food-web structure, and alter nutrient pulse dynamics. In lentic ecosystems, hydroclimatic extremes control hydroperiod length and timing, which are critical drivers of meta-population and meta-community structure and dynamics. Nevertheless, ecological impacts of increasing hydroclimatic variability are difficult to anticipate from discrete observations alone because the influences of extreme events occur through a wide range of mechanisms (abiotic and biotic) and spatio-temporal scales. Within this context, statistical models (e.g., state-space models on time-series data) may be important tools to increase understanding of these mechanisms and potentially anticipate effects of increasing hydroclimatic variability on freshwater biodiversity and ecosystem functioning. Although the use of these models is still limited - partly due to the scarcity of temporally-extensive data sets - increasing availability of long-term ecological data sets and "big data" may open many opportunities in the near future. This session will be devoted to the discussion of statistical modeling approaches that may effectively link hydroclimatic forcing to ecological responses, and to their data requirements, potential, and limitations. Ultimately, we would like to exemplify and synthesize the range of tools that are available to freshwater ecologists to anticipate impacts of hydroclimatic extremes, across spatio-temporal scales and levels of biological organization.

Title: Status, threats, and conservation of freshwater mussels during a water crisis

S09: Conservation of Freshwater Mussels

Organizer: Erin Miller (emiller428@gmail.com)

Freshwater mussels are one of the most endangered groups of animals on Earth (Williams et al. 1993, Bogan 2008). Nearly three-quarters of all 297 native freshwater mussel species in North America are imperiled and 35 are thought to have gone extinct in the last century (Stein et al. 2000). Ninety-eight percent of the endemic mollusk taxa in California are considered vulnerable to extinction (Howard et al. 2015).

These past losses and future threats to freshwater mussels are directly attributed to the degradation of aquatic ecosystems. In particular, freshwater mussels are sensitive to changes in their environment, and rely on fish to reproduce and sustain their populations. Habitat loss and declines of native fish species have had significant impacts on mussel populations. Freshwater mussels have been deemed the "canary in a coalmine" of North American rivers (Nedeau et al. 2009).

Human population growth, increasing demands for freshwater resources, and climate change are predicted to exacerbate stresses on freshwater ecosystems and lead to further imperilment and extinction of freshwater taxa (Howard at al. 2015). Yet, major gaps remain in our understanding freshwater mussel biology, distribution, status, and threats (Nedeau et al. 2009). Of particular concern for the future of freshwater mollusks is how water quality, habitat fragmentation, hydrologic alteration, global climate change, altered water levels, and loss or reduction of host fish will have an effect on our last remaining native populations (Nedeau et al. 2009). Filling these knowledge gaps is essential to inform current and future water management decisions while providing for conser-vation of freshwater mussels (Howard et al. 2015).

The goal of this session is to address these knowledge gaps. How can we use the knowledge we have to inform future research efforts, address issues associated with a water crisis, and provide for the conservation of an imperiled animal group?

Title: Rivers at risk: Existing and emerging threats to river ecosystems

S10: Rivers at Risk

Organizer: Laura Craig (lcraig@americanrivers.org), Erin Singer McCombs

Rivers and streams are the most impacted ecosystems on the planet as a consequence of exploitation for water supply, irrigation, power generation, navigation, and waste disposal. They are also susceptible to the impacts of watershed alteration, a result of their inextricable connection to the terrestrial ecosystem stemming from their low-lying position on the landscape. Threats to river ecosystems include urban and agricultural land use, resource extraction, water withdrawals, climate change, invasive species, habitat fragmentation, and emerging contaminants, among others. These threats directly or indirectly impact stream ecosystems through changes in hydrology, geomorphology, water chemistry, habitat quantity and quality, and species composition. River ecosystems provide habitat for diverse communities, corridors for dispersal and migration, locations for uptake and transformation of nutrients, natural flood control, and other important ecological roles. At the same time, humans continue to benefit from the goods and services provided by rivers. River conservation and management relies on balancing human uses with ecological values and a comprehensive understanding of how various threats - both existing and anticipated - will impact rivers both alone and in combination. Many rivers are experiencing multiple threats simultaneously, leading to the need for complex management approaches. This special session provides a 'big picture' view of the major threats facing rivers. It brings together scientists with particular expertise related to existing or emerging threats to rivers to review the body of knowledge related to each of these threats and efforts to minimize their impacts (e.g., restoration, stormwater management, protection), with a broader goal of elucidating opportunities for future scientific inquiry to address conservation and management needs.

Title: Next-generation sequencing in freshwater science

S11: Next-Generation Sequencing in Freshwater Science

Organizer: Scott Hotaling (scott.hotaling@uky.edu), Brian A. Gill, Debra Finn, and Jane Hughes

In recent years, molecular techniques have become increasingly important in freshwater science. With the development of next-generation sequencing (NGS) technologies, the scale of data and the associated analytical tools have opened new avenues of research within freshwater research and extended longstanding ones. These new opportunities are diverse, spanning a large swath of questions from the characterization of microbial communities to identifying genes implicated in adaptation. In addition to new opportunities, NGS tools have also increased the resolution by which we can assess traditional questions of population differentiation, gene flow, and demography. For many biologists, the scale and computational requirements of research with NGS-scale data is a daunting challenge. The goal of this special session is to bring together scientists that are currently using NGS-data to ask relevant questions across the organismal and scientific spectrum, to provide broader exposure to the utility of these methods for researchers interested in leveraging NGS technologies in their own research programs, and to provide a launching point for future collaborations.

Title: Cities and streams: What are the biogeochemical symptoms of urban stream syndrome?

S12: Urban Stream Syndrome

Organizers: Alex Reisinger (reisingera@caryinstitute.org), Joanna R. Blaszczak, Sylvia S. Lee, Peter S. Levi and Emma J. Rosi-Marshall (rosimarshalle@caryinstitute.org)

Urbanization is altering the natural structure and function of stream ecosystems at the global scale. As urban land use continues to expand, urban streams are increasingly affected by a myriad of common environmental stressors. These stressors include hydrogeomorphic alterations (e.g., stream burial, channelization), chemical stressors originating from point and non-point sources (e.g., road salts, nutrients), and other chemicals associated with dense human populations (e.g., pharmaceuticals and personal care products). While the functional response of urban streams may vary with these multivariate physical and chemical stressors, variation in response to any one stressor across streams in different urban areas may be small given the occurrence of common stressors across urban areas. Until recently, few studies have investigated the response of ecosystem function in urban streams to provide a robust comparison. In our special session, we seek to understand whether biogeochemical processes in streams respond similarly to urban stressors across diverse biomes. For example, headwater streams across urban areas often have open canopies and high ambient nutrient concentrations, potentially fueling high rates of gross primary production (GPP). In contrast, GPP in a prairie stream may be limited by nutrients, not light, whereas both nutrients and light may limit GPP in a forested stream. However, while high light and nutrient availability in urban streams may enhance GPP, additional stressors such as increased scour, habitat loss, and contaminant loading may have contrasting effects, limiting productivity. In this special session, we will focus on the biogeochemistry of urban streams, paying particular attention to 1) functional responses to increasing urbanization and 2) homogenization across urban environments. We invite colleagues studying urban streams from urban areas across the globe to explore the patterns in ecosystem stressors, functions, and the relationship between these factors. We hope to discuss the implications of biogeochemical responses, and potential management approaches to optimize the functioning of urban stream ecosystems in light of other anthropogenic changes.

Title: A confluence of aquatic research influenced by Vince Resh

S13: Session for Vince Resh

Organizers: Michael Peterson (petersmg@berkeley.edu), Gary Lamberti, Jack Feminella

Professor Vince Resh has an incredible, distinguished career in freshwater science research. He contributes to the Society for Freshwater Science through research publications, leadership roles, and mentorship. This special session is will examine the research that has contributed to our current knowledge of freshwater ecosystems through the lens of Professor Resh's contributions to the field. From his initial research on sculpin and caddisfly biology in the early 1970s, Vince has crafted a career in research that contributes to the basic biology of aquatic insects and environmental applications of this knowledge for disease control and bioassessment of aquatic ecosystems. Through a career interwoven with many colleagues and graduate students, Resh's research has commonly included caddisflies and mosquitoes, in addition to organisms from unique aquatic systems such as Sylvan Springs in Yellowstone National Park and island streams in French Polynesia. His research has taken extended forays into freshwater issues that include vectors of human disease, the role of disturbance in streams, and determination of reference conditions, among others. In addition, his research and leadership have helped develop large-scale biomonitoring programs in North America, Europe, Africa, and Asia. This special session will include contributed talks on many of these topics to synthesize the history of Professor Resh's role in our field and the society. While his research has included major river systems throughout the world, his work in California on Mediterranean streams, biodiversity, and anthropogenic impacts is timely for the 2016 Society for Freshwater Science meeting in Sacramento.

Note: Participants in this session are permitted to submit one additional abstract to a different session.

Title: Multiple stressors in river ecosystems: Defining present situations and anticipating challenges

S14: Multiple Stressors in River Ecosystems

Organizers: Sergi Sabater (sergi.sabater@udg.edu), Vicenç Acuña, Mazeika P. Sullivan, Arturo Elosegi

As a consequence of global environmental change, river ecosystems are affected by an increasing number of stressors occurring simultaneously, including water abstraction and regulation, excess nutrients, contamination, and biotic invasions, among many others. These stressors can exert strong influences on biodiversity and ecosystem function, threatening river conservation, undermining the ecosystem services they provide, and constituting important challenges for management. This session invites case studies where multi-stressor situations can be analyzed and compared across spatial scales and geographic regions. We anticipate that the collective contributions to this session will aid in identifying common effects on ecosystem function, conservation, and ecosystem services of rivers under multi-stressor scenarios and thus increase current understanding on the consequences of environmental change at regional and global scales.

Title: Putting your publications to work: Synthesis of literature-based evidence to inform environmental decision making

S15: Putting Your Publications to Work

Organizer: Sue Nichols (sue.nichols@canberra.edu.au), Kate Schofield, Sue Norton, Angus Webb, Andreas Melcher, Mike Peat

Worldwide, there is increasing demand for 'evidence-based' environmental management, but little guidance exists as to what this actually means or how to implement it. Evidence-based practice is based on the assumption that scarce resources should be invested in actions that are likely to be effective, given available scientific knowledge. Ideally, science should contribute to management decisions through systematic review of the available evidence using a transparent and logically defensible process. A wealth of evidence about how different sources and stressors can affect aquatic systems is published in the scientific literature, but often much of this evidence is not clearly and effectively evaluated when making management decisions. The methods and examples presented in this session explore evidence synthesis and how it can be better used to inform freshwater ecosystem management. What attributes lead to rapid, accurate and informative syntheses? What challenges are there when bringing literature-based evidence to bear in environmental decision-making? Is there an 'ideal' evidence synthesis method? Efficient and defensible methods for evidence synthesis would greatly increase the effective use of scientific research results to better manage natural environments.

Title: Algal data as a critical component of bioassessment: Obtaining useful results in the face of continued taxonomic fluidity

S16: Algal Data as a Component of Bioassessment

Organizers: Julianne Heinlein, Gina LaLiberte (gina.laliberte@wisconsin.gov)

Algal taxonomy, as is the case with most microbial taxonomy, is in a constant state of flux. New molecular evidence has led to change in many generic and species concepts. Also, identification of taxa using light microscopy can be challenging due to difficulty in resolution of distinctive characteristics, cryptic species, and inherent phenotypic plasticity and morphological variability. Variable sampling and laboratory approaches also contribute to limitations in algal species identification. Because of these issues we may find algal data falling below the Quality Control criteria that were developed for other organisms, raising concerns about the validity and utility of such data. The goal of this session is to 1) illustrate the robustness and necessity of traditional algal bioassessment metrics in spite of this taxonomic fluidity; 2) explore the use of new metrics [e.g., using higher-level taxonomy, taxonomic lump levels, community types (species co-occurrence)]; 3) show the benefit of using soft algal metrics for many bioassessment questions; 4) address the importance of identifying the data set or analysis that is most appropriate and efficient for answering a particular question; and 5) investigate how algal metrics fare in increasingly wide-spread drought-stricken areas . Large and small-scale algal bioassessments are used worldwide to improve evaluation of issues within aquatic systems, leading to better management plans. Presentations will be representative of those using algal assessment in management as well as those doing academic research.

Title: Stressed forested watersheds: Understanding the disturbance response of aquatic-riparian ecosystems

S17: Stressed Forested Watersheds

Organizers: Alex Yeung (yeungcheeyu@gmail.com), Maitane Erdozain Ibarra, Jordan Musetta-Lambert

Aquatic systems are intricately linked to adjacent and upland terrestrial environments, and in large part, these ecological linkages are directed through riparian zones. Forest disturbances can have multi-scale complex effects on the structure and functioning of aquatic-riparian systems (local), which can propagate to downstream waters (catchment). Major anthropogenic forest disturbances include forest harvesting, agricultural and urban development, and natural disturbances include wind-throw, fire, insect outbreak and drought. Multiple disturbances may co-occur and interact to compromise important ecosystem functioning at the aquatic-riparian interface, such as flood mitigation, temperature regulation, nutrient and sediment retention, and organic matter inputs. However, periodic natural disturbances, such as fire, could facilitate regeneration and improve the resilience of some forest systems. This serves as the theoretical basis for recent forest management practices that emulate natural disturbances through riparian harvesting. Therefore, it is critical to understand anthropogenic and natural disturbance regimes, and the ensuing aquatic-riparian ecosystem responses to inform future watershed management.

In this special session, we anticipate contributions which address (1) how forest disturbances affect the physical, hydrologic, chemical, and biological characteristics of aquatic-riparian ecosystems, and their consequences on terrestrial-aquatic and upstream-downstream linkages; (2) how these effects vary across spatial and temporal scales, and gradients of disturbance severity; and (3) how knowledge of disturbance responses could be incorporated to manage forested watersheds and maintain ecosystem service delivery.

The characteristics of disturbance regimes (e.g. intensity, frequency) are known to result in variable impacts on stream-riparian interactions, which are mediated by climatic and topographic conditions, and vegetation types. Some disturbance types can modify forest structure and community patterns, causing legacy effects that persist decades after disturbance. We welcome studies investigating disturbance responses across broad environmental gradients, and on a multi-year or -decade basis describing trajectories of ecosystem recovery.

In North America, forested watersheds are under increasing stress. Fires and harvesting become more prevalent in both temperate and boreal forests, droughts intensify along the west coast (particularly in California), and fires, logging and beetle infestations combine to drive forest loss in the Intermountain West. As these disturbances also occur along with climate change, it is timely and of growing public concern to reflect upon our current understanding (and knowledge gaps), and make predictions of how natural and anthropogenic disturbances in forested watersheds could influence aquatic-riparian conditions and the health of receiving waters. This special session is expected to bring in international expertise to discuss ways to maintain watershed health, and sustainably manage future forest and water resources together.

Title: Community engagement in science and stewardship of freshwater resources

S18: Community Engagement in Science

Organizer: Erick Burres (Erick.Burres@waterboards.ca.gov)

Community based research and participation in freshwater resource stewardship is an important part of the responses to our current and future water crisis. This session will highlight experiences in uniting the public (citizens) and resources managers (agencies) through science based watershed research and management. Nationwide communities and their citizens are becoming increasingly more engaged in these activities through citizen science, volunteer monitoring, STEM, CBO stewardship projects and programs such as AmeriCorps.

Title: Solving the "Running on Empty" problem through Collaborative Learning and Interdisciplinary Freshwater Foundations (CLIFF): An honorary session for Cliff Dahm

S19: Session for Cliff Dahm

Organizers: Jennifer F. Shah (follstad@gmail.com), Michelle Baker, Rebecca Bixby, Anna Hamilton, Mary Harner, Lydia Zeglin

This special session is dedicated to the career of Dr. Clifford N. Dahm, whose diverse interests regarding research and aquatic resource management are unified through interdisciplinary collaboration. As a graduate student and postdoc, Cliff applied his training in chemistry, oceanography, microbiology, and biogeochemistry to tests of the river continuum concept and interdisciplinary, collaborative study of ecosystem responses to the eruption of Mount St. Helens. These activities advanced our understanding of stream and lake biogeochemistry, while illustrating the importance of biological and geological controls at local and landscape scales. Cliff's collaborative research efforts continued among the multi-departmental Hydrogeoecology Research Group at the University of New Mexico (UNM), the Sevilleta Long-Term Ecological Research (LTER) Group, and multi-investigator projects, including the Nitrogen Retention and Partitioning Study (NPARS) and Lotic Intersite Nitrogen eXperiments (LINX I and II). These activities increased our knowledge regarding hydrologic, biogeochemical, climatic, and land use controls on water quantity and nutrient processing in streams and rivers. Cliff supported ecosystem science for two years as a National Science Foundation (NSF) Division of Biology Program Officer. He was later awarded NSF IGERT funds to implement an interdisciplinary doctoral program in freshwater science at the UNM and the University of Alabama. His holistic perspective led him out of the stream to study evapotranspiration of semi-arid to arid riparian ecosystems to better quantify catchment-scale water budgets. His interest in applying science to public policy regarding water availability and ecosystem integrity led Cliff to participate in the Kissimmee River Restoration Project, National River Restoration Science Synthesis Project, and Rivers Institute in Australia. Collaborations among ecologists, hydrologists, geomorphologists, climatologists, engineers, and social scientists were common to these efforts. Cliff served as Lead Scientist for the Delta Science Program from 2008-2012. After "retirement" from the UNM in 2015, he returned for a one-year assignment to help guide California water resource management towards a more sustainable path. Cliff is a member of the Science Steering Group for the Global Water Budget Program of the U.S. Global Change Research Program. He also participates in the Intermittent River Biodiversity Analysis and Synthesis (IRBAS) Project and GLOBAQUA, international collaborations concerned with the management of aquatic systems under multiple stressors and increasing water scarcity. Session speakers will include colleagues from Cliff's early career to today, as well as former students and postdocs. Presentations will highlight the ways Cliff has influenced water science and management, especially in ecosystems susceptible to "running on empty".

Note: Participants in this session are permitted to submit one additional abstract to a different session.

Title: Ecological subsidies to stream and riparian ecosystems

S20: Ecological Subsidies to Stream and Riparian Ecosystems

Organizers: Clay Arango (ArangoC@cwu.edu), Sally Entrekin

The role that ecological subsidies play in stream and riparian ecosystems is likely to change as human use of surface water increases and as drought incidence and thermal stress become more common from climate change. For example, salmon spawners provide ecological subsidies by delivering marine derived nutrients to oligotrophic streams, but adult salmon will be subject to less water availability when they return, possibly increasing their subsidy through concentration effects. Alternatively, they could be subject to increased thermal stress, potentially decreasing their subsidy by reduced populations. Furthermore, widespread drought predicted to occur across the American West will increase the incidence of insect outbreaks, yet the ecological subsidy of insect herbivores in coniferous forests remains largely undescribed. Increased drought could increase the ecology subsidy of outbreak insects through population and concentration effects, but increased fire frequency could reduce their subsidy by removing the trees that support them. There is an immediate need to develop a broader understanding of how ecological subsidies might affect connectivity between stream and riparian ecosystems and their ecosystem productivity under rapidly changing environmental conditions.

The interaction of ecological subsidies with environmental conditions is a timely topic given recent research findings. Thomas et al. (2015) recently explored how restoring broad leaf riparian forest could buffer thermal effects of climate change on salmonids, but found site-specific effects and no overarching pattern. Similarly, Bellmore et al. (2014) developed a model suggesting that understanding environmental context was necessary to predict stream response to salmon spawners. A special session focused on ecological subsidies between riparian and stream ecosystems would benefit those actively researching this topic, particularly in the context of our current inability to predict how rapid environmental change might alter the ecological role of subsidies in freshwater and riparian ecosystems under future climate change scenarios.

Title: Balancing the freshwater budget: Compensatory mitigation in an uncertain future

S21: Balancing the Freshwater Budget

Organizers: Joseph Morgan (Morgan.Joseph@epa.gov), Kenton Sena

Freshwater ecosystems face an uncertain future as they are forced to compete with human development and infrastructure for scarce water and space resources. An important facet of the problem of preserving freshwater ecosystem functions is offsetting aquatic resource impacts through restoration, creation, enhancement or preservation of aquatic resources elsewhere, known as "compensatory mitigation." Compensatory mitigation requirements represent a significant source of ecological restoration projects, and also drives a multi-million dollar mitigation banking industry. Since its inception in the 1970's, compensatory mitigation has been the subject of various disputes surrounding its ecological value and administrative oversight. To address these concerns, the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency jointly issued regulations revising and clarifying standards for compensation projects, known collectively as the 2008 Mitigation Rule. Significant changes in the character of compensatory mitigation have accompanied the implementation of these regulations, including an increased focus on in-kind compensatory mitigation for stream impacts and pronounced growth in the mitigation banking industry due to the preference expressed for third-party forms of compensation in the 2008 Mitigation Rule.

As both the volume and expectations of compensatory mitigation projects increase, it is essential to determine whether compensation projects are effectively replacing lost functions; however, a recent report from Morgan and Hough (2015) found that evaluations of compensatory mitigation performance have actually declined in frequency since the issuance of the 2008 Mitigation Rule. Disturbingly, temporal trends in compensation performance remain largely unknown as few follow-up studies are conducted, and increasing political and economic instability makes a long-term vision for compensation performance difficult. Streams in particular seem to be a neglected aquatic resource in the field of compensatory mitigation; several recent studies have noted that many stream compensation projects employ outdated and/or unsupported approaches to ecological restoration. As markets and requirements for stream compensation continue to grow, ecological research linking discrete restoration goals and practices is sorely needed to properly develop performance standards that ensure these projects can adequately offset permitted losses.

This session will elucidate the problems currently facing compensatory mitigation and investigate potential solutions, inviting a range of speakers from academic, regulatory, and consulting backgrounds to share their experience and visions for the future of compensatory mitigation. We also propose that the session be followed by a roundtable discussion (on- or off-site), where invited speakers will have an opportunity to interact with each other and conference attendees in an open and informal setting.

Title: Considering spatial and temporal scale in biotic responses to food web alterations

S22: Biotic Responses to Food Web Alterations

Organizers: Janine Rüegg (janine.ruegg@epfl.ch), Brooke Penaluna, Alba Argerich

Environmental change can affect food webs in a multitude of ways: species declines or extirpation due to altered nutrient, thermal, or hydrologic regimes, the introduction of non-native species, or direct anthropogenic influences such as fisheries harvest. These alterations have not only consequences for the individual species, but the changes in populations and communities, and thus the food webs they are a part of, will likely lead to alterations in the structure and function of aquatic ecosystems. The changes in species' abundance(s) can alter aquatic ecosystem structure and function via top-down or bottom-up effects, alteration or disruption of energy flow to other trophic levels, or changes of the environmental conditions, depending on the trophic position, life history, and/or ecological roles (e.g., keystone species, ecosystem engineers) of the affected species. The scope of such foodweb alterations can be fairly small, such as the introduction or loss of a fish species in an individual pond or lake, or relatively large, such as the decline of anadromous fish migrations affecting 1000s of kilometers of stream and the receiving estuary. In addition, foodweb alterations may persist for a variable length of time. For example, drought directly affects ecosystem function due to the loss of water and increases in stream temperature, but may persist beyond the period of drought if reproductive success of longer-living species was lowered. Responses to food web alterations are often context- and/or scale-dependent, such that changes in ecosystem function due to the loss of large-bodied consumers may differ between upstream and downstream reaches of a catchment, but the responses upstream may also be evident downstream. To apply findings of changes in ecosystem structure and function due foodweb alterations, which are often studied at fine spatial and temporal scales, to broader scales needed for management, maintenance, restoration, or preservation of aquatic ecosystems, knowledge of spatial and temporal variation and scale of biotic responses to foodweb alteration, as well as the context of such responses, is critical.

Title: Traits-based vulnerability assessment and monitoring under climate change

S23: Traits-Based Vulnerability Assessment

Organizers: Britta Bierwagen (Bierwagen.britta@epa.gov), Anna Hamilton, and Jen Stamp

Vulnerability assessments of aquatic communities, as well as monitoring to document ongoing population, community, and habitat responses to climate change impacts, are increasingly utilized to inform decisions and help direct conservation, restoration, and other resource management efforts. While specific management actions are typically implemented at a local level, the scope of planning for climate change adaptation calls for understanding and comparing climate change impacts and vulnerabilities over a larger spatial scale. A traits-based approach can be an effective means for conducting assessments at multiple scales, by providing comparability across geographic regions that may have differing species pools. If, as is widely believed, the environment filters species based on intrinsic traits such as life history, morphological, and behavioral characteristics, and even extrinsic characteristics such as demographic traits, then a traits-based approach has the potential to provide a better mechanistic link between pattern and process than a taxonomic-based approach, and lead to greater insights into why certain vulnerability patterns are observed. Traits-based assessments can thus improve predictive ability, and provide results that are less susceptible to taxonomic ambiguities or inconsistencies. On the other hand, traits-based vulnerability assessment is still in its developmental stage, and confounding issues remain. For example, there are interrelationships among traits (termed "trait syndromes") that make it difficult to know which combinations of traits are most adaptive to particular environmental conditions. Traits may respond in tandem to environmental gradients, complicating interpretation and potentially producing counterintuitive results. Trait variations resulting from phenotypic plasticity, genotypic responses to the environment, or ontogeny can make assignment of traits problematic. And on a simple level, there are still many gaps in our knowledge of traits for many taxonomic groups. To advance our understanding in how traits and trait suites can be used in vulnerability assessment and monitoring, we propose to focus a special session on cutting-edge traits research and advances in traits-based vulnerability and monitoring applications. We will place emphasis on traits related to low flows, drought, and other changes in flow, given the SFS theme "Running on Empty."

Title: Scale and ecosystem functions-When and why do small- and large-scale or short- and long-term measurements align?

S24: Scale and Ecosystem Functions

Organizers: John Kominoski (jkominoski@gmail.com), Amy Rosemond

There is an urgent need to understand how ecosystems are responding to global change drivers and to quantify structure and functional metrics that adequately indicate good or compromised health of ecosystems. Understanding how key ecosystem functions integrate multiple biotic and abiotic components of systems across spatial and temporal scales is key to include in assessing health and integrity beyond the scale of most measurements. In many cases, it is more tractable to quantify ecosystem functions using patch-level measurements (e.g., 1 ï‚´ 1 m plots), which sample only small areas of larger and more complex ecosystems. It is unknown under what conditions and for what ecosystem functions larger scale processes can be predicted from those measured at small scales. Our session will explore how various physical (discharge, temperature), chemical (nutrient concentrations, stoichiometric ratios, and loading rates), and biological drivers (gross primary productivity, ecosystem respiration) differentially affect our ability to accurately scale up or scale down measurements of ecosystem functions. We invite participation from individuals studying all aquatic ecosystem types (lake, stream, wetland). A systematic, comparative approach scaling relationships will be assessed by bringing together empirical data from different ecosystem types and across different measures of function: gross primary productivity, community respiration, carbon loss and breakdown rates, and nutrient uptake rates. The questions that we will focus on are the following: 1) What abiotic and biotic factors theoretically influence fit between small- and large-scale of short- and long-term for a particular function?; 2) What empirical evidence exists for fit or lack of fit among spatiotemporal scales for these various ecosystem functions?; and 3) In what cases are we most likely to over or under estimate measurements when scaling up and scaling down?

Title: Modeling environmental change in freshwater ecosystems

S25: Modeling Environmental Change in Freshwater Ecosystems

Organizers: Mathias Kuemmerlen (mkuemmerlen@senckenberg.de), Sami Domisch

Climate change, land use intensification, water shortages and a growing population are just some of the consequences of human development in an era that has been called the Anthropocene. These changes to natural systems are widespread and occur faster than it often possible to measure. Obtaining a "big picture" of their effects of freshwater biodiversity may take decades. Ecological models can provide valuable insights into how the changing environmental conditions will reshape abundances, distributions, communities or even ecosystem functions by using data available today. Further, modelling procedures help speed up the identification of critical environmental drivers, as well as their trends in their recent and future expected changes. This session aims at bringing together ecological modelling efforts focusing on the effects of global environmental change on freshwater biodiversity, its causes and its consequences.

Title: Exploring trophic relationships and stream food webs using novel modeling approaches

S26: Exploring Trophic Relationships and Stream Food Webs

Organizers: Claire Ruffing (cmruffing@alaska.edu), Sherri Johnson

This Special Session will showcase innovative research in modeling food web dynamics while highlighting new directions for furthering trophic theory in freshwater systems. An improved understanding of trophic dynamics is a premier challenge for ecologists in light of the increasing number of environmental changes facing stream environments. Food web dynamics encompass the transfer of energy across trophic levels within an ecosystem and integrate both the living and nonliving components of ecosystems. Much of what is known through experimentation or direct observation of food webs in freshwater ecosystems is limited in either scope or scale because of unavoidable constraints related to data collection. Modeling provides a valuable and effective way to overcome some of these traditional constraints associated with researching food webs in a realistic, yet replicable way.

Modeling techniques can take a variety of forms and provide opportunities to incorporate greater degrees of complexity and account for variations in ecosystem conditions. Mechanistic modeling approaches incorporate clear operational definitions of system components and behavior and are useful for testing hypotheses over a range of simulations and scenarios. Statistical and structural equation modeling examine causal hypotheses and correlative relationships between ecosystem components that are then explicitly defined, tested, and evaluated in a quantitative way. Building on recent advances in data collection, analytical and computing capabilities, novel applications of mechanistic and statistical modeling approaches can be used to explore new frontiers in our understanding of trophic theory and dynamics, as well as responses to disturbances and anthropogenic activities. We welcome any contributors who use mechanistic and statistical modeling approaches to investigate food webs or trophic dynamics in freshwater ecosystems. The topics might include examining factors influencing basal resources, secondary production, species interactions, biodiversity, community food webs, bioenergetics, or other related topics such as food chain length, trophic cascades, and food web stability.

Contaminants as agents of ecological change in freshwaters

S27: Contaminants as Agents of Ecological Change

Organizers: Michelle Hornberger (mhornber@usgs.gov), Emma Rosi-Marshall (rosimarshalle@caryinstitute.org)

Exploration of the effects of contaminants on freshwater ecosystem dynamics within the field of stream ecology has been somewhat limited in the past. We plan to convene a special session to explore the intersection between contaminants and freshwater ecology to highlight recent advances in both fields and to examine new areas for future research. Freshwater science has traditionally not investigated the influence of contaminants on ecological processes and the field of toxicology is often narrowly targeted and are applied at scales inconsistent with natural processes that freshwater scientists consider. The inherent variability of chemical, physical and biological processes simultaneously occurring in natural systems may lead freshwater ecologists to consider contaminants as additional non-important drivers of ecological processes. Despite the many challenges, it is fundamentally important to understand whether freshwater ecosystem processes are potentially influenced by contaminants. Ultimately, the understanding the health of freshwater ecosystems depends on a holistic understanding of the interrelationships of ecosystem processes and the contaminants that are commonly detected in freshwaters. This session will highlight recent advances and case studies that have investigated the role of contaminants as factors affecting ecosystem processes. The range of speakers selected will focus on measurements of contaminant flux through ecosystems and the effects of various contaminants on ecosystem processes, and will describe how research on contaminants will provide new insights into our understanding of freshwater ecosystems. We hope this session will both highlight exciting new areas of research and provide a path forward for future research that explores the ecological consequences of contaminated freshwaters.