Location of Winchester Dam, OR, and upstream drainage basin.

<p>Winchester Dam was built in 1890 and upgraded in 1907 and now includes a timber-crib structure that is 4.9 m in height. While the dam does impound a shallow upstream reservoir, it is considered a “run-of-river” dam. A fish ladder allowing fish passage was installed in 1945 with a viewing window to monitor the upstream passage of all fishes past the dam. Continuously collected fish passage data at this location from 1992 and 2013 was used to develop the Winchester Dam ichthyograph.</p

Daily streamflow, water temperature and fish counts for Winchester Dam, North Umpqua River, Oregon, USA from 1992 to 2013.

<p>Streamflow (top graph) from USGS gage station No. 14319500. Stream temperature (second graph from top) and fish counts courtesy Oregon Department of Fish and Wildlife for, in order: steelhead (anadromous <i>Oncorhynchus mykiss</i>), sucker (<i>Catostomus macrocheilus</i>), Chinook Salmon (<i>Oncorhynchus tshawytscha</i>), lamprey (<i>Entosphenus tridentatus</i>), cutthroat trout (<i>Oncorhynchus clarkii</i>), and Coho Salmon (<i>Oncorhynchus kisutch</i>). Fish count data unavailable for Jan–Oct 1998. This figure shows a multi-year timeline plot of environmental conditions (daily streamflow and water temperature) and the community of fishes moving upstream past Winchester Dam. Darker colors are associated with higher numbers and show strong seasonal patterns over time for all species. Some species have narrow upstream migration windows (i.e. Coho Salmon) while others move upstream during a wider time window (i.e. steelhead).</p

Linking Hydroclimate to Fish Phenology and Habitat Use with Ichthyographs

<div><p>Streamflow and water temperature (hydroclimate) influence the life histories of aquatic biota. The relationship between streamflow and temperature varies with climate, hydrogeomorphic setting, and season. Life histories of native fishes reflect, in part, their adaptation to regional hydroclimate (flow and water temperature), local habitats, and natural disturbance regimes, all of which may be affected by water management. Alterations to natural hydroclimates, such as those caused by river regulation or climate change, can modify the suitability and variety of in-stream habitat for fishes throughout the year. Here, we present the <i>ichthyograph</i>, a new empirically-based graphical tool to help visualize relationships between hydroclimate and fish phenology. Generally, this graphical tool can be used to display a variety of phenotypic traits. We used long-term data sets of daily fish passage to examine linkages between hydroclimate and the expression of life-history phenology by native fishes. The ichthyograph may be used to characterize the environmental phenology for fishes across multiple spatio-temporal domains. We illustrate the ichthyograph in two applications to visualize: 1) river use for the community of fishes at a specific location; and 2) stream conditions at multiple locations within the river network for one species at different life-history stages. The novel, yet simple, ichthyograph offers a flexible framework to enable transformations in thinking regarding relationships between hydroclimate and aquatic species across space and time. The potential broad application of this innovative tool promotes synergism between assessments of physical characteristics and the biological needs of aquatic species.</p></div

Conceptual ichthyographs for Coho Salmon.

<p>Conceptual ichthyographs for Coho Salmon use by life stage of: (a) a mid-river location such as Winchester dam, and (b) throughout the river network with generalized patterns of streamflow and stream temperature for different drainage areas. These conceptual ichthyographs are based on the empirical data available in this system (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168831#pone.0168831.g001" target="_blank">Fig 1</a>), but also incorporate informal data collected as part of ongoing fish management in this system, and the description of life-stage specific habitat characteristics that can be taken from the peer reviewed literature. Other species specific traits could be mapped in this way, as could other interpretations of fish habitat use beyond specific life stages. Empirical ichthyographs that map daily discharge, temperature, and fish use could also be mapped where data are available.</p

Streamflow and stream temperature related to fish passage timing at Winchester Dam, OR.

<p>Multiple years of streamflow and stream temperature, when plotted against one another on a graph, may show a cyclical pattern. Such is the case at Winchester Dam, OR when streamflow and stream temperature for the period of record (1992–2103) is plotted as: (a) average daily values; inset) generalized seasonal relationship creating an annual cycle of hydrologic conditions. When fish passage is overlaid on the framework of discharge and temperature, an ichthyograph is created: (b) ichthyograph of daily fish use at Winchester Dam based on data from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0168831#pone.0168831.g001" target="_blank">Fig 1</a>. Various other phenological traits could be plotted in this way, with ideal data based on empirical observation, as is the case at Winchester Dam, OR.</p

Trends in Fry Emergence of Trout across Scenarios.

<p>DOY from five replicate simulations when median number of modeled fry had emerged over time in Gus Creek, Pothole Creek, Rock Creek, and Upper Mainstem (UM). Scenarios include manipulations of stream temperature and flow regimes (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135334#sec002" target="_blank">methods</a> narrative for detail). Only significant trends (P < 0.05) over time are listed and include the slope of the trend (days per decade). Negative values represent early fry emergence. Gaps in data are due to years with no fry emergence because model thresholds for spawning, egg development, or emergence were not met.</p

Representation of Key Processes in inSTREAM.

<p>We highlight how the daily time series inputs of stream temperature, flow, and turbidity drive individual growth and survival and hence population dynamics including responses of fry emergence and biomass. A more detailed explanation of inSTREAM can be found in [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135334#pone.0135334.ref020" target="_blank">20</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135334#pone.0135334.ref021" target="_blank">21</a>].</p

Pairwise Comparisons for Differences in Total Summer Biomass between Scenario and Baseline.

<p>Pairwise comparisons of total biomass (g) of trout in summer for forest harvest (FH), climate change (CC), and combined (FH + CC) scenarios compared to baseline in modeled streams, including Gus Creek, Pothole Creek, Rock Creek, and Upper Mainstem (UM). Values of summer biomass by year were averaged for five replicate simulations and were analyzed using Wilcoxon signed rank test (V) with continuity correction resulting in a pseudomedian of difference between scenario and baseline (Δ) for the 1^st harvest period, 2^nd harvest period, and the entire study period. Scenarios include manipulations of stream temperature and flow regimes (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135334#sec002" target="_blank">Methods</a> for details). Significant p-values in bold (alpha ≤ 0.05) represent increasing or decreasing magnitudes in comparison to baseline.</p><p>Pairwise Comparisons for Differences in Total Summer Biomass between Scenario and Baseline.</p

Local Variability Mediates Vulnerability of Trout Populations to Land Use and Climate Change

<div><p>Land use and climate change occur simultaneously around the globe. Fully understanding their separate and combined effects requires a mechanistic understanding at the local scale where their effects are ultimately realized. Here we applied an individual-based model of fish population dynamics to evaluate the role of local stream variability in modifying responses of Coastal Cutthroat Trout (<i>Oncorhynchus clarkii clarkii</i>) to scenarios simulating identical changes in temperature and stream flows linked to forest harvest, climate change, and their combined effects over six decades. We parameterized the model for four neighboring streams located in a forested headwater catchment in northwestern Oregon, USA with multi-year, daily measurements of stream temperature, flow, and turbidity (2007–2011), and field measurements of both instream habitat structure and three years of annual trout population estimates. Model simulations revealed that variability in habitat conditions among streams (depth, available habitat) mediated the effects of forest harvest and climate change. Net effects for most simulated trout responses were different from or less than the sum of their separate scenarios. In some cases, forest harvest countered the effects of climate change through increased summer flow. Climate change most strongly influenced trout (earlier fry emergence, reductions in biomass of older trout, increased biomass of young-of-year), but these changes did not consistently translate into reductions in biomass over time. Forest harvest, in contrast, produced fewer and less consistent responses in trout. Earlier fry emergence driven by climate change was the most consistent simulated response, whereas survival, growth, and biomass were inconsistent. Overall our findings indicate a host of local processes can strongly influence how populations respond to broad scale effects of land use and climate change.</p></div

Influence of Flow and Temperature on Trout Biomass within each Scenario.

<p>Boxplots of mean total summer biomass (g) of trout in Gus Creek, Pothole Creek, Rock Creek, and Upper Mainstem (UM) from five replicate simulations over the entire study period. Each boxplot incorporates 63 data points of the mean of every year’s summer biomass per scenario. Gray boxes represent pairwise comparisons of the influence of flow (Q), stream temperature (T), and both (Q+T) within each scenario of forest harvest (FH) and climate change (CC). Baseline and the combined scenarios (FH+CC) are shown for reference. Scenarios include manipulations of stream temperature and flow regimes (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135334#sec002" target="_blank">methods</a> narrative for detail). Significant pairwise differences are shown by a horizontal black line (P < 0.05). Significant differences between baseline and each scenario are noted. The point above or below each boxplot corresponds to the 5^th and 95^th percentile.</p