scholarly journals Habitat affinity and density‐dependent movement as indicators of fish habitat restoration efficacy

Ecosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Carlos M. Polivka
Keyword(s):  
Habitat Restoration ◽  
Fish Habitat ◽  
Density Dependent ◽  
Habitat Affinity

scholarly journals Habitat affinity and density-dependent movement as indicators of fish habitat restoration efficacy

2019 ◽  
Author(s):  
Carlos M. Polivka
Keyword(s):  
Behavioral Ecology ◽  
Habitat Restoration ◽  
Pacific Salmon ◽  
Fish Habitat ◽  
Explanatory Power ◽  
Habitat Characteristics ◽  
Density Data ◽  
Trade Offs ◽  
Effectiveness Studies ◽  
Habitat Affinity

AbstractConceptual and methodological tools from behavioral ecology can inform studies of habitat quality and their potential for evaluating habitat restoration in conservation efforts is explored here. Such approaches provide mechanistic detail in understanding the relationship between organisms and their habitats and are thus more informative than correlations between density and habitat characteristics. Several Pacific salmon species have been the target of habitat restoration efforts for the past 2-3 decades, but most post-restoration effectiveness studies have been limited to correlative data described above. In mark-recapture assays from four different study years, the affinity of sub-yearling Chinook salmon (Oncorhynchus tschawytscha) and steelhead (O. mykiss) for stream pools restored with or created by engineered log structures was greater than that for pools without restoration, though with high interannual variability. From corresponding distribution and density data, it was clear that habitat affinity data are not always concordant with single observations of density. The same was true of the correlation between either affinity or density and physical characteristics of pools, although depth and current velocity had some explanatory power for both responses in Chinook. Movement into pools by Chinook during the assays indicated that restored pools can support more immigrants at a given density than can unrestored pools; however no such pattern emerged for steelhead. Variation among individuals in body condition has implications for population-wide fitness, and such low variation was correlated with stronger affinity for pools in Chinook regardless of restoration status. This suggests that pools may mediate habitat-related trade-offs and that restoring them might have a positive effect on fitness. Thus affinity, immigration, and condition data give much-needed mechanistic indication of habitat selection for restored habitat via an apparent capacity increase and those potential fitness benefits. This is stronger support for restoration effectiveness than density differences alone because density data 1) may simply indicate redistribution of fish from poor to good habitats and 2) are not adequate to show correlations between restoration and positive change in traits correlated with fitness.

Using confidence intervals to estimate the response of salmon populations (Oncorhynchus spp.) to experimental habitat alterations

2005 ◽  
Vol 62 (12) ◽  
pp. 2716-2726 ◽  
Author(s):  
Michael J Bradford ◽  
Josh Korman ◽  
Paul S Higgins
Keyword(s):  
Confidence Intervals ◽  
Effect Size ◽  
Null Hypothesis ◽  
Statistical Power ◽  
Habitat Restoration ◽  
Coho Salmon ◽  
Fish Habitat ◽  
Monitoring Program ◽  
Considerable Uncertainty ◽  
Monitoring Programs

There is considerable uncertainty about the effectiveness of fish habitat restoration programs, and reliable monitoring programs are needed to evaluate them. Statistical power analysis based on traditional hypothesis tests are usually used for monitoring program design, but here we argue that effect size estimates and their associated confidence intervals are more informative because results can be compared with both the null hypothesis of no effect and effect sizes of interest, such as restoration goals. We used a stochastic simulation model to compare alternative monitoring strategies for a habitat alteration that would change the productivity and capacity of a coho salmon (Oncorhynchus kisutch) producing stream. Estimates of the effect size using a freshwater stock–recruit model were more precise than those from monitoring the abundance of either spawners or smolts. Less than ideal monitoring programs can produce ambiguous results, which are cases in which the confidence interval includes both the null hypothesis and the effect size of interest. Our model is a useful planning tool because it allows the evaluation of the utility of different types of monitoring data, which should stimulate discussion on how the results will ultimately inform decision-making.

Fish habitat restoration using large wood: Linking stream geomorphic change and fish response

2020 ◽  
pp. 1723-1729
Author(s):  
C. Segura ◽  
A. Yeager ◽  
C. Lorion
Keyword(s):  
Habitat Restoration ◽  
Fish Habitat ◽  
Large Wood ◽  
Fish Response

scholarly journals An integrated population model for estimating the relative effects of natural and anthropogenic factors on a threatened population of Pacific trout

2019 ◽  
Author(s):  
Mark D. Scheuerell ◽  
Casey P. Ruff ◽  
Joseph H. Anderson ◽  
Eric M. Beamer
Keyword(s):  
At Risk ◽  
Population Model ◽  
Habitat Restoration ◽  
Negative Relationship ◽  
Anthropogenic Factors ◽  
List Type ◽  
Population Demographics ◽  
Density Dependent ◽  
Integrated Population Model ◽  
The North

SummaryAssessing the degree to which at-risk species are regulated by density dependent versus density independent factors is often complicated by incomplete or biased information. If not addressed in an appropriate manner, errors in the data can affect estimates of population demographics, which may obfuscate the anticipated response of the population to a specific action.We developed a Bayesian integrated population model that accounts explicitly for interannual variability in the number of reproducing adults and their age structure, harvest, and environmental conditions. We apply the model to 41 years of data for a population of threatened steelhead troutOncorhynchus mykissusing freshwater flows, ocean indices, and releases of hatchery-born conspecifics as covariates.We found compelling evidence that the population is under strong density dependence, despite being well below its historical population size. In the freshwater portion of the lifecycle, we found a negative relationship between productivity (offspring per parent) and peak winter flows, and a positive relationship with summer flows. We also found a negative relationship between productivity and releases of hatchery conspecifics. In the marine portion of the lifecycle, we found a positive correlation between productivity and the North Pacific Gyre Oscillation. Furthermore, harvest rates on wild fish have been sufficiently low to ensure very little risk of overfishing.Synthesis and applications.The evidence for density dependent population regulation, combined with the substantial loss of juvenile rearing habitat in this river basin, suggests that habitat restoration could benefit this population of at-risk steelhead. Our results also imply that hatchery programs for steelhead need to be considered carefully with respect to habitat availability and recovery goals for wild steelhead. If releases of hatchery steelhead have indeed limited the production potential of wild steelhead, there are likely significant tradeoffs between providing harvest opportunities via hatchery steelhead production, and achieving wild steelhead recovery goals.

scholarly journals TECHNIQUES TO EVALUATE THE EFFECTIVENESS OF FISH HABITAT RESTORATION WORKS IN STREAMS IMPACTED BY LOGGING ACTIVITIES

1998 ◽  
Vol 23 (2) ◽  
pp. 191-203 ◽  
Author(s):  
C. Wendell Koning ◽  
Pat A. Slaney ◽  
Marc N. Gaboury ◽  
Michael D. Feduk
Keyword(s):  
Habitat Restoration ◽  
Fish Habitat

Can fish habitat restoration for rheophilic species in highly modified rivers be sustainable in the long run?

2016 ◽  
Vol 88 ◽  
pp. 28-38 ◽  
Author(s):  
Joachim Pander ◽  
Juergen Geist
Keyword(s):  
Habitat Restoration ◽  
Fish Habitat ◽  
Long Run

Consequences of potential density-dependent mechanisms on recovery of ocean-type chinook salmon (Oncorhynchus tshawytscha)

2004 ◽  
Vol 61 (4) ◽  
pp. 590-602 ◽  
Author(s):  
Correigh M Greene ◽  
Timothy J Beechie
Keyword(s):  
Density Dependence ◽  
Chinook Salmon ◽  
Habitat Restoration ◽  
Oncorhynchus Tshawytscha ◽  
High Sensitivity ◽  
Leslie Matrix ◽  
Relative Importance ◽  
Density Dependent ◽  
Habitat Area ◽  
Leslie Matrix Model

Restoring salmon populations depends on our ability to predict the consequences of improving aquatic habitats used by salmon. Using a Leslie matrix model for chinook salmon (Oncorhynchus tshawytscha) that specifies transitions among spawning nests (redds), streams, tidal deltas, nearshore habitats, and the ocean, we compared the relative importance of different habitats under three density-dependent scenarios: juvenile density independence, density-dependent mortality within streams, delta, and nearshore, and density-dependent migration among streams, delta, and nearshore. Each scenario assumed density dependence during spawning. We examined how these scenarios influenced priorities for habitat restoration using a set of hypothetical watersheds whose habitat areas could be systematically varied, as well as the Duwamish and Skagit rivers. In all watersheds, the three scenarios shared high sensitivity to changes in in nearshore and ocean mortality and produced similar responses to changes in other parameters controlling mortality (i.e., habitat quality). However, the three scenarios exhibited striking variation in population response to changes in habitat area (i.e., capacity). These findings indicate that nearshore habitat relationships may play significant roles for salmon populations and that the relative importance of restoring habitat area will depend on the mechanism of density dependence influencing salmon stocks.

scholarly journals Beaver activity increases habitat complexity and spatial partitioning by steelhead trout

2019 ◽  
Vol 76 (7) ◽  
pp. 1086-1095 ◽  
Author(s):  
Gus Wathen ◽  
Jacob E. Allgeier ◽  
Nicolaas Bouwes ◽  
Michael M. Pollock ◽  
Daniel E. Schindler ◽  
...  
Keyword(s):  
Habitat Complexity ◽  
Habitat Restoration ◽  
Fish Habitat ◽  
Castor Canadensis ◽  
Small Scale ◽  
Microhabitat Use ◽  
Spatial Partitioning ◽  
Management Actions ◽  
Microhabitat Heterogeneity ◽  
Positive Correlations

Freshwater habitat restoration is a major conservation objective, motivating efforts to restore habitat complexity and quality for fishes. Restoration based on the engineering activities of beavers (Castor canadensis) increases fish habitat complexity, but how this affects fish habitat use and movement behaviours is not well known. We used a network of passive integrated transponder antennas to quantify small-scale movement and microhabitat use of 175 individual juvenile steelhead (Oncorhynchus mykiss) in a stream channel with a complex bathymetric profile resulting from a beaver impoundment and in a simplified channel devoid of beaver activity. Our results show that juvenile steelhead exploit microhabitat heterogeneity by employing a range of behaviours that maximizes available habitat via spatial and temporal partitioning among individuals. These results suggest spatial resource partitioning as a potential mechanism for the previously established positive correlations among steelhead density, survival, and production with beaver-based restoration within the study watershed. More broadly, our findings provide insight as to how populations can exploit habitat complexity through spatial partitioning that can be informative for planning restoration and management actions.

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