6/06/2017  |   09:00 - 09:15   |  302C

NON-STATIONARITY AND THE NEED FOR AN EXPANDED FRAMEWORK FOR FLOW-ECOLOGY RELATIONSHIPS Non-stationarity in hydrologic and ecological conditions represent an emerging, key challenge to e-flows science as currently practiced. As e-flows transitions from a sole restoration focus to a broader adaptation focus, flow-ecology relationships grounded in the natural flow regime concept will continue to provide the foundation of e-flows applications. Clear specification of flow-ecology relationships is critical to shaping justifiable management expectations and attaining e-flows success. Advancing e-flows science under non-stationarity requires that e-flows science develop a more dynamic “process-based” understanding of hydro-ecological relationships, to allow for more dynamic and responsive management. Implicit in this approach is the need to clearly identify scale of application in e-flows applications, insofar as methods and tools available to quantify flow-ecology relationships present scale-dependent tradeoffs in hydro-geomorphic modelling precision and in ecological responses. At present, ecological response variables are typically static descriptors of low frequency state variables over large spatial extents. However, other ecological variables, including ecological rates and species traits, can and should be employed to extend the spatial and temporal domains of an evolving e-flows science.

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


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6/06/2017  |   09:15 - 09:30   |  302C

Assessment of environmental flow scenarios using state-transition models A large number of methods have been developed to assessment environmental flow requirements for rivers. Most methods are based on models of hydrologic time-series rather than models of the ecological endpoints. Important limitations that arise from this include 1) an inability to represent the state-dependency of response to future conditions, 2) the inability to predict actual states through time under some hypothesized future flow regime, and 3) limited sensitivity to compare flow scenarios with similar return intervals of ecologically important events, but different sequencing of those events. Here we present a simple state-transition modelling approach to assess differences in ecological responses to alternative sequences of floodplain inundation events in a large lowland river system. Our approach explicitly incorporates the state-dependency of response to flooding, thereby representing the influences of both antecedent conditions and current population status. Our approach captures the influence of the entire historical sequence of flow events via a first-order Markov chain process. We use prior data and expert opinion to determine state-transitions for a broad suite of ecological indicators. The outputs from the models are testable, and the approach is readily extensible to incorporate additional complexity.

Nick Bond (Primary Presenter/Author), La Trobe University, n.bond@latrobe.edu.au;


Nicky Grigg ( Co-Presenter/Co-Author), CSIRO, Nicky.Grigg@csiro.au;


Heather McGinness ( Co-Presenter/Co-Author), CSIRO, Heather.Mcginness@csiro.au;


Daryl Nielsen ( Co-Presenter/Co-Author), CSIRO, Daryl.Nielsen@csiro.au;


Ian Overton ( Co-Presenter/Co-Author), CSIRO, ian.overton@csiro.au;


Carmel Pollino ( Co-Presenter/Co-Author), CSIRO Land and Water, Carmel.Pollino@csiro.au;


Julian Reid ( Co-Presenter/Co-Author), Australian National University, julian.reid@anu.edu.au;


Jane Roberts ( Co-Presenter/Co-Author), University of Canberra, jroberts@netspeed.com.au;


Danial Stratford ( Co-Presenter/Co-Author), CSIRO, Danial.Stratford@csiro.au;


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6/06/2017  |   09:30 - 09:45   |  302C

HIGH FLOWS DECREASE FISH POPULATIONS IN THE CURRENT YEAR BUT INCREASE POPULATIONS THE FOLLOWING YEAR Hydrology is thought to exert strong control on lotic fish populations, but relationships between specific flow metrics and actual abundances only rarely have been quantified. We used long-term fish count data to test specific hypotheses of flow ecology relationships in two contrasting river systems: (1) the highly biodiverse Etowah River in Georgia, USA, and (2) a set of streams in Nevada, USA that support Lahontan cutthroat trout (Onchorhynchus clarkii henshawii). We used autoregressive population models incorporating density dependence to test the effects of high flows on population growth rates. We found that for cutthroat trout and for 9 of 12 shoal-dwelling species in the Etowah, high flows reduced growth rates in the current year (i.e., reduced abundance relative to the prior year), but increased growth rates in the succeeding year. We argue that the most likely explanation for this pattern is scouring that causes immediate mortality but increases primary and secondary productivity, thereby increasing recruitment to adult stage. We also illustrate the benefits of modeling growth rate rather than repeated measures of abundance as a response variable.

Seth Wenger (Primary Presenter/Author), University of Georgia, sethwenger@fastmail.fm;


Phillip Bumpers ( Co-Presenter/Co-Author), University of Georgia, bumpersp@gmail.com;


Mary Freeman ( Co-Presenter/Co-Author), US Geological Survey, mcfreeman@usgs.gov;


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


Kit Wheeler ( Co-Presenter/Co-Author), TN Tech University, kitwheeler@gmail.com;


Mary Peacock ( Co-Presenter/Co-Author), University of Nevada Reno, mpeacock@unr.edu;


Megan Hagler ( Co-Presenter/Co-Author), University of Georgia, ms.meganhagler@gmail.com;


Bud Freeman ( Co-Presenter/Co-Author), University of Georgia, bud@hemip.nhm.uga.edu;


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6/06/2017  |   09:45 - 10:00   |  302C

EFLOWSIM: A SIMULATION FRAMEWORK TO ASSESS SAMPLING DESIGNS AND ANALYTICAL APPROACHES FOR DETECTING FLOW-ECOLOGY RELATIONSHIPS Identifying ecological responses to stream hydrology has become an urgent research priority in the face of mounting pressures on water resources, but it is unclear how sampling design and analytical methods influence our ability to detect flow-ecology relationships in different conditions. Using the statistical framework of spatio-temporal population viability analysis, we have developed a simulation tool that can 1) simulate population time series with user-defined flow effects on population growth rates and carrying capacities and 2) simulate removal sampling data based on user-defined sampling designs. The simulated data can be used to assess our ability to recover known parameters with different sampling designs and analytical approaches. To mimic real-world scenarios, the simulation framework allows significant customization of parameters: flow effects, demographic stochasticity, spatial clumping, per-pass detection rates, number of years of sampling, number of sites sampled per year and their sizes, number of passes conducted, etc. We will walk through the simulation process and present assessments of a few common sampling designs in their abilities to estimate true site abundances, flow effects on population processes, and population trends.

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


Seth Wenger ( Co-Presenter/Co-Author), University of Georgia, sethwenger@fastmail.fm;


Mary Freeman ( Co-Presenter/Co-Author), US Geological Survey, mcfreeman@usgs.gov;


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6/06/2017  |   10:00 - 10:15   |  302C

COMBINING DYNAMIC OCCUPANCY MODELS AND TRAIT-BASED APPROACHES TO ASSESS THE RESPONSE OF STREAM FISH ASSEMBLAGES TO HYDROLOGICAL AND HYDROTHERMAL VARIABILITY Effective management and conservation of aquatic communities is a challenging task. Dynamic occupancy models provide an excellent framework for assessing the predominant factors influencing patch dynamics (colonization and extinction) of fishes in lotic systems. Trait-based approaches, which involve the grouping of taxa based on shared characteristics, are similarly useful for generalizing the responses of stream fishes to a variety of factors. Combined, these approaches enable managers to assess how natural- and human-induced changes in streamflow conditions influence fish assemblages. Consideration of species traits may be particularly advantageous for rare species that are difficult to study, as rare species often share traits - and potentially shared responses - with more abundant or widely distributed and co-occurring species. Using two example studies, one involving darter assemblages in Tennessee and another involving oxbow fish assemblages in Iowa, we demonstrate the use of multi-species dynamic occupancy modeling combined with groupings based on species traits to assess the response of fishes to hydrological and hydrothermal variability. We believe that this approach provides managers with valuable insight into how aquatic species may respond to future management and conservation activities.

Colin Shea (Primary Presenter/Author), Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL 33701, USA, colin.shea@myfwc.com;


Bryan Bakevich ( Co-Presenter/Co-Author), New Mexico Department of Game and Fish, Santa Fe, NM 87504, USA, Bryan.Bakevich@state.nm.us;


Phil Bettoli ( Co-Presenter/Co-Author), U.S. Geological Survey, Tennessee Cooperative Fishery Research Unit, Tennessee Technological University, Cookeville, TN 380505, USA, pbettoli@tntech.edu;


Jesse Fischer ( Co-Presenter/Co-Author), North Carolina State University, jessefischer@gmail.com;


Clay Pierce ( Co-Presenter/Co-Author), U.S. Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, 2310 Pammel Drive, Ames, IA 50011, USA, cpierce@iastate.edu;


Michael Quist ( Co-Presenter/Co-Author), U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, Moscow, ID 83844, USA, mcquist@uidaho.edu;


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6/06/2017  |   10:15 - 10:30   |  302C

DYNAMIC OCCUPANCY MODELS SUGGEST PHYSIOGRAPHY INFLUENCES STREAM FISH COLONIZATION BUT NOT PERSISTENCE IN A SOUTHEASTERN RIVER BASIN Many freshwater taxa have distributions that overlap multiple, distinct physiographic regions, yet relationships between physiography and demographic processes that drive metapopulation dynamics are rarely examined. We addressed physiographic influence on metapopulation dynamics using stream fishes as model organisms. We used periodic survey data from 40 southeastern U.S. streams representing three physiographic regions and fitted these data to multi-season, multi-species dynamic occupancy models to estimate colonization and persistence rates as functions of physiography and streamflow magnitude. Our modeling results suggest that stream fish colonization but not persistence is strongly governed by physiography, with estimated colonization rates considerably higher in Coastal Plain streams than in Piedmont and Blue Ridge systems. Like colonization, persistence was positively related to an index of streamflow magnitude, but the relationship between flow and persistence did not depend on physiography. Given the importance of colonization to population demography, we suggest that physiographic influences on metapopulation dynamics could be important considerations in the management and conservation of stream fishes, as well as other broadly distributed taxa.

Kit Wheeler (Primary Presenter/Author), TN Tech University, kitwheeler@gmail.com;


Mary Freeman ( Co-Presenter/Co-Author), US Geological Survey, mcfreeman@usgs.gov;


Seth Wenger ( Co-Presenter/Co-Author), University of Georgia, sethwenger@fastmail.fm;


Stephen Walsh ( Co-Presenter/Co-Author), US Geological Survey, swalsh@usgs.gov;


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