scholarly journals Beyond redistribution: In-stream habitat restoration increases capacity for young-of-the-year Chinook salmon and steelhead in the Entiat River, WA

2019 ◽  
Author(s):  
Carlos M. Polivka ◽  
Shannon M. Claeson
Keyword(s):  
Chinook Salmon ◽  
Habitat Restoration ◽  
Fish Habitat ◽  
Stream Habitat ◽  
Computational Statistics ◽  
Modal Density ◽  
Unit Scale ◽  
Field Methodology ◽  
Young Of The Year ◽  
Bayesian Generalized Linear Model

AbstractWe conducted snorkel surveys for juvenile salmonids in reaches of the Entiat River (Washington, USA) treated with engineered log jams (ELJs), and in reaches without treatments, to determine if habitat-unit-scale observations can identify whether restoration has increased the habitat capacity of a reach. The conceptual basis and field methodology emphasize fish density data (fish/habitat area in m2) from unrestored habitat within a reach treated with ELJs compared to surveys in 1) unrestored habitat in untreated reaches and 2) restored habitat in treated reaches. A Bayesian generalized linear model enabled us to quantify density differences among habitat types using advanced computational statistics. Modal density of young-of-the-year Chinook salmon (Oncorhynchus tschawytscha) and steelhead (O. mykiss) was at least 3.1-fold and 2.7-fold greater, respectively, in restored habitat compared with unrestored habitat for all treated reaches examined. To distinguish the density differences in those reaches as capacity increases rather than redistribution from poor habitat to good habitat, we compared density in unrestored habitat in both treated and untreated reaches. Here we found no differences for either species, confirming that the increased density in restored habitat units did not come from depletion of unrestored habitat in the same reach. We thus concluded that restoration increased the habitat capacity of the reach at the scale of pools created by ELJs.

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.

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.

scholarly journals Ancient DNA Analysis of Archaeological Specimens Extends Chinook Salmon’s Known Historic Range to San Francisco Bay and Its Southernmost Watershed

2020 ◽  
Author(s):  
Richard B. Lanman ◽  
Linda Hylkema ◽  
Cristie M. Boone ◽  
Brian Alleé ◽  
Roger O. Castillo ◽  
...  
Keyword(s):  
Native American ◽  
San Francisco ◽  
Ancient Dna ◽  
Chinook Salmon ◽  
Habitat Restoration ◽  
Dna Analysis ◽  
Oncorhynchus Tshawytscha ◽  
San Francisco Bay ◽  
Bay Area ◽  
Guadalupe River

Understanding a species’ historic range guides contemporary management and habitat restoration. Chinook salmon ( Oncorhynchus tshawytscha ) are an important commercial and recreational gamefish, but nine Chinook subspecies are federally threatened or endangered due to anthropomorphic impacts. Several San Francisco Bay Area streams and rivers currently host spawning Chinook populations, but government agencies consider these non-native hatchery strays. Using ichthyofaunal analysis of 17,288 fish specimens excavated from Native American middens at Mission Santa Clara circa 1781-1834 CE, 86 salmonid vertebrae were identified. Ancient DNA sequencing identified three of these as from Chinook salmon and the remainder from steelhead trout. These findings comprise the first physical evidence of the nativity of salmon to the Guadalupe River in San Jose, California, extending their historic range to include San Francisco Bay’s southernmost watershed.

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