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Title: The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape

Abstract

Density-dependent (DD) and density-independent (DI) habitat selection is strongly linked to a species’ evolutionary history. Determining the relative importance of each is necessary because declining populations are not always the result of altered DI mechanisms but can often be the result of DD via a reduced carrying capacity. Here, we developed spatially and temporally explicit models throughout the Chena River, Alaska to predict important DI mechanisms that influence Chinook salmon spawning success. We used resource-selection functions to predict suitable spawning habitat based on geomorphic characteristics, a semi-distributed water-and-energy balance hydrologic model to generate stream flow metrics, and modeled stream temperature as a function of climatic variables. Spawner counts were predicted throughout the core and periphery spawning sections of the Chena River from escapement estimates (DD) and DI variables. In addition, we used isodar analysis to identify whether spawners actively defend spawning habitat or follow an ideal free distribution along the riverscape. Aerial counts were best explained by escapement and reference to the core or periphery, while no models with DI variables were supported in the candidate set. Moreover, isodar plots indicated habitat selection was best explained by ideal free distributions, although there was strong evidence for active defense of coremore » spawning habitat. These results are surprising, given salmon commonly defend spawning resources, and are likely due to competition occurring at finer spatial scales than addressed in this study.« less

Authors:
ORCiD logo [1];  [2];  [3];  [4];  [5]
  1. Univ. of Alaska, Fairbanks, AK (United States). Inst. of Arctic Biology
  2. Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey
  3. Alaska Dept. of Fish and Game, Fairbanks, AK (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Univ. of Alberta, Edmonton, AB (Canada)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1396138
Report Number(s):
LA-UR-17-27606
Journal ID: ISSN 1932-6203
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 60 APPLIED LIFE SCIENCES; Earth Sciences

Citation Formats

Huntsman, Brock M., Falke, Jeffrey A., Savereide, James W., Bennett, Katrina E., and Boyce, Mark S. The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape. United States: N. p., 2017. Web. doi:10.1371/journal.pone.0177467.
Huntsman, Brock M., Falke, Jeffrey A., Savereide, James W., Bennett, Katrina E., & Boyce, Mark S. The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape. United States. doi:10.1371/journal.pone.0177467.
Huntsman, Brock M., Falke, Jeffrey A., Savereide, James W., Bennett, Katrina E., and Boyce, Mark S. Mon . "The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape". United States. doi:10.1371/journal.pone.0177467. https://www.osti.gov/servlets/purl/1396138.
@article{osti_1396138,
title = {The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape},
author = {Huntsman, Brock M. and Falke, Jeffrey A. and Savereide, James W. and Bennett, Katrina E. and Boyce, Mark S.},
abstractNote = {Density-dependent (DD) and density-independent (DI) habitat selection is strongly linked to a species’ evolutionary history. Determining the relative importance of each is necessary because declining populations are not always the result of altered DI mechanisms but can often be the result of DD via a reduced carrying capacity. Here, we developed spatially and temporally explicit models throughout the Chena River, Alaska to predict important DI mechanisms that influence Chinook salmon spawning success. We used resource-selection functions to predict suitable spawning habitat based on geomorphic characteristics, a semi-distributed water-and-energy balance hydrologic model to generate stream flow metrics, and modeled stream temperature as a function of climatic variables. Spawner counts were predicted throughout the core and periphery spawning sections of the Chena River from escapement estimates (DD) and DI variables. In addition, we used isodar analysis to identify whether spawners actively defend spawning habitat or follow an ideal free distribution along the riverscape. Aerial counts were best explained by escapement and reference to the core or periphery, while no models with DI variables were supported in the candidate set. Moreover, isodar plots indicated habitat selection was best explained by ideal free distributions, although there was strong evidence for active defense of core spawning habitat. These results are surprising, given salmon commonly defend spawning resources, and are likely due to competition occurring at finer spatial scales than addressed in this study.},
doi = {10.1371/journal.pone.0177467},
journal = {PLoS ONE},
number = 5,
volume = 12,
place = {United States},
year = {Mon May 22 00:00:00 EDT 2017},
month = {Mon May 22 00:00:00 EDT 2017}
}

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  • Knowledge of the three-dimensional connectivity between rivers and groundwater within the hyporheic zone can be used to improve the definition of fall chinook salmon (Oncorhynchus tshawytscha) spawning habitat. Information exists on the microhabitat characteristics that define suitable salmon spawning habitat. However, traditional spawning habitat models that use these characteristics to predict available spawning habitat are restricted because they can not account for the heterogeneous nature of rivers. The authors present a conceptual spawning habitat model for fall chinook salmon that describes how geomorphic features of river channels create hydraulic processes, including hyporheic flows, that influence where salmon spawn in unconstrainedmore » reaches of large mainstem alluvial rivers. Two case studies based on empirical data from fall chinook salmon spawning areas in the Hanford Reach of the Columbia River are presented to illustrate important aspects of the conceptual model. The authors suggest that traditional habitat models and the conceptual model be combined to predict the limits of suitable fall chinook salmon spawning habitat. This approach can incorporate quantitative measures of river channel morphology, including general descriptors of geomorphic features at different spatial scales, in order to understand the processes influencing redd site selection and spawning habitat use. This information is needed in order to protect existing salmon spawning habitat in large rivers, as well as to recover habitat already lost.« less
  • From 1986 to 1995, over US$2.5 million has been spent or allocated for projects to modify channel conditions to improve spawning habitat for chinook salmon Oncorhynchus tshawytscha in the Merced. Tuolumne, and Stanislaus rivers, tributaries to the San Joaquin River, California. The authors evaluated the planning, design and performance of the Riffle 1B reconstruction on the Merced River. This typical of the nine individual riffle reconstructions completed to date. involving excavation of the existing channel bed (here, to 0.6 m) and back-filling with smaller gravels believed to be more suitable for salmon spawning. Project documents were reviewed, agency staff interviewed,more » and field surveys conducted to document channel conditions in 1994 for comparison with the project as constructed in 1990. The project planning and design did not consider the site`s geomorphic context nor processes of erosion and sediment transport under the current flow regime. As a consequence, spawning-sized gravel placed in the channel was scoured and transported through the site at a flow with a return period of 1.5 years. The need for spawning habitat enhancement in the Merced River is questionable, but if such projects are to be built, the authors recommend that the project planning and design consider the site`s geomorphic context and acknowledge the need for and provide funds for project maintenance, and that the performance of completed projects be systematically monitored and evaluated. 32 refs., 8 figs., 1 tab.« less
  • Previously we reported that about 30% to 60% of the area predicted to be used by fall Chinook salmon (Oncorhynchus tshawytscha) for spawning in the Hanford Reach of the Columbia River did not contain redds. One explanation for the overprediction of habitat was that our model did not incorporate streamflow fluctuation. Daily fluctuation in flow caused by load-following operations (power generation to meet short-term electrical demand) at Priest Rapids Dam, situated at the upper end of the Hanford Reach, changes the hydraulic characteristics to which fish respond in selecting redd sites. The purpose of the study described here was tomore » examine the effect of flow changes on spawning habitat modeling and, in particular, to look at the connection between spawning and the variability and persistence of habitat variables caused by rapid changes in flow resulting from load-following operations at Priest Rapids Dam. We found that spawning habitat use by fall Chinook salmon was consistent with previous fall Chinook salmon studies in the Reach. Dynamic variables that were based on hourly time series were used to account for the variability in habitat as a result of flow fluctuations. The analysis showed that the proportion of velocities that fell within the range of 1.0 to 2.5 m/s differed significantly between locations that were predicted to be spawning by the logistic regression model where spawning actually occurred and locations that were predicted to be spawning where spawning did not occur. However, the resulting sequential logistic regression model that incorporated the dynamic variables did not provide significant improvement in the percentage of errors for areas predicted to be spawning; the model’s overprediction errors still ranged from 63% to 78%. We suggest that while flow fluctuation may affect spawning habitat and individual fish behavior, the high correlation between time-averaged velocities and the proportion of hourly velocities that fell within the most favorable range negated any improvements in model predictions.« less
  • We improved our predictions of fall chinook salmon (Oncorhynchus tshawytscha) habitat use by analyzing spawning habitat at the spatial scale of redd clusters. Spatial point pattern analyses indicated that redd clusters in the Hanford Reach, Columbia River, were consistent in their location from 1994 to 1995. Redd densities were 16.1 and 8.9 redds?ha-1 in 1994 and 1995, respectively, and individual redds within clusters were usually less than 30 m apart. Pattern analysis also showed strong evidence that redds were uniformly distributed within the clusters where inter-redd distances ranged from 2 to 5 m. Redd clusters were found to occur predominantlymore » where water velocity was between 1.4 to 2 m?s-1, water depth was 2 to 4 m, and lateral slope of the riverbed was less than 4%. This habitat use represented a narrower range of use than previously reported for adult fall chinook salmon. Logistic regression analysis determined that water velocity and lateral slope were the most significant predictors of redd cluster location over a range of river discharges. Over-estimates of available spawning habitat lead to non-achievable goals for protecting and restoring critical salmonid habitat. Better predictions of spawning habitat may be possible if cluster-specific characteristics are used.« less
  • Chief Joseph Dam on the Columbia River is the upstream terminus for anadromous fish, due to its lack of fish passage facilities. Management agencies are currently evaluating the feasibility of reintroducing anadromous fish upriver of Chief Joseph Dam. We evaluated the physical characteristics of potential fall chinook salmon (Oncorhynchus tshawytscha) spawning habitat in the upper section of Chief Joseph Reservoir. The objective of this study was to estimate the quantity and location of potential spawning habitat, and secondly to determine the redd capacity of the area based on spawning habitat characteristics. We used a geomorphic approach to first identify specificmore » segments with the highest potential for spawning. The suitability of these segments for spawning was then estimated through the use of empirical physical data and modeled hydraulic data. We estimated 5% (48.7 ha) of the study area contains potentially suitable fall chinook salmon spawning habitat. Potential spawning habitat is primarily limited by water too deep and secondly by water velocities too low, the combination of which results in 20% (9.6 ha) of the potential spawning habitat being characterized as high quality. Estimates of redd capacity within potential spawning habitat range from 207? 1599 redds, based on proportional use of potential habitat and varying amounts of channelbed used by spawning salmon. The results of our study provide fisheries managers significant insight into one component of the complex issue of reintroducing anadromous fish to the Columbia River upstream of Chief Joseph Dam.« less