Assessing covariability among populations in the presence of intraseries correlation: Columbia River spring-summer chinook salmon (<i>Oncorhynchus tshawytscha</i>) stocks

Botsford, Louis W.; Paulsen, Charles M.

doi:10.1139/f00-007

Cited by 27 publications

(25 citation statements)

References 9 publications

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“…Previous studies focusing on longer time series of smolt-adult return rate and adult returns have found support for climate teleconnections (Beamish & Bouillon, 1993;Mantua et al, 1997;Lawson et al, 2004;Scheuerell & Williams, 2005). Nevertheless, our results consistently showed that in the Lemhi River, flow variables had stronger explanatory power than climate predictors, corroborating some studies that have detected higher covariation in life-cycle production at subbasin rather than basinwide scales (Schaller et al, 1999;Botsford & Paulsen, 2000;Deriso et al, 2001). Studies that have included flow as well as climate signals in the context of the life cycle have also shown strong effects of flow (e.g., Greene et al 2005).…”

Section: Discussionsupporting

confidence: 89%

Contrasting life-cycle impacts of stream flow on two Chinook salmon populations

et al. 2010

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Stream flow affects many aspects of freshwater fish biology, but the extent to which variation in stream flow influences productivity of anadromous salmonid populations across their entire life cycle is not well known. We compared relationships of stream flow and productivity for Chinook salmon (Oncorhynchus tshawytscha) from two systems in the Salmon River basin in Idaho: the Lemhi River, a watershed subjected to intensive water use for irrigation, and Marsh Creek, a drainage with a natural hydrograph. We estimated rates of productivity based on monitoring at four life stages: the number of eggs initiating each cohort, juveniles migrating from the natal tributary past an outmigrant trap, smolts surviving to the Snake River, and adults returning to spawn. Using model selection techniques, we examined whether river flow experienced during these life stages explained variation above and beyond predictors of climate associated with each stage. In the Lemhi River, tributary stream flow during early residence exhibited strong correlations with egg-trap, egg-smolt, and egg-adult return rates, and was consistently a better predictor of productivity than stream flow occurring during late summer. Model selection indicated that early rearing flow was the single best predictor of both egg-trap and trap-smolt transition rates in the Lemhi River, and path analysis revealed a strong set of pathways linking rearing flow to adult return rate primarily through egg-trap productivity. These patterns were much less strongly exhibited or nonexistent in Marsh Creek. However, for both populations, migration flow in the Columbia River was the best predictor of smolt-adult return rates. Potentially confounding climatic variables exhibited relatively weak effects upon both early life histories and tributary flow, but were included in the best models of migration flows and smolt-adult return rate. These results suggest that effects of stream flow on juvenile salmonids in flow-altered systems can have substantial impacts on returning adults.

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Section: Discussionsupporting

confidence: 89%

Contrasting life-cycle impacts of stream flow on two Chinook salmon populations

et al. 2010

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“…A sequential Bonferroni correction (29) was applied to adjust significance levels for multiple comparisons. Because LOWESS smoothing will produce spatially autocorrelated data (regional trends), the effective degrees of freedom for significance tests of cross-correlations can be lower than the standard tests (30,31). Therefore, significance values close to 0.05 should be taken with caution.…”

Section: Methodsmentioning

confidence: 99%

Scales of benthic–pelagic coupling and the intensity of species interactions: From recruitment limitation to top-down control

Navarrete

Wieters²,

Broitman³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

233

267

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Large and usually unpredictable variation in species interaction strength has been a major roadblock to applying local experimental results to large-scale management and conservation issues. Recent studies explicitly considering benthic-pelagic coupling are starting to shed light on, and find regularities in, the causes of such large-scale variation in coastal ecosystems. Here, we evaluate the effects of variation in wind-driven upwelling on community regulation along 900 km of coastline of the southeastern Pacific, between 29°S and 35°S during 72 months. Variability in the intensity of upwelling occurring over tens of km produced predictable variation in recruitment of intertidal mussels, but not barnacles, and did not affect patterns of community structure. In contrast, sharp discontinuities in upwelling regimes produced abrupt and persistent breaks in the dynamics of benthic and pelagic communities over hundreds of km (regional) scales. Rates of mussel and barnacle recruitment changed sharply at Ϸ32°-33°S, determining a geographic break in adult abundance of these competitively dominant species. Analysis of satellite images demonstrates that regional-scale discontinuities in oceanographic regimes can couple benthic and pelagic systems, as evidenced by coincident breaks in dynamics and concentration of offshore surface chlorophyll-a. Field experiments showed that the paradigm of top-down control of intertidal benthic communities holds only south of the discontinuity. To the north, populations seem recruitment-limited, and predators have negligible effects, despite attaining similarly high abundances and potential predation effects across the region. Thus, geographically discontinuous oceanographic regimes set bounds to the strength of species interactions and define distinct regions for the design and implementation of sustainable management and conservation policies.coastal ecosystems ͉ upwelling ͉ community regulation ͉ Chile

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“…This assumption is more appropriate for long-distance dispersal than straying between neighboring subpopulations. For salmon (and other homing fish) environmental factors such as stream temperature, flow rates, and food supply are likely to be more correlated between neighboring stocks (Botsford and Paulsen 2000). Analysis of classical metapopulation models have shown that spatially correlated environmental stochasticity potentially reduces mean extinction times (e.g., Levins 1969;Gilpin 1990;Hanski 1991).…”

Section: Diffusion Theory For a Stochastic Metapopulation Modelmentioning

confidence: 99%

The Effects of Small Dispersal Rates on Extinction Times in Structured Metapopulation Models

Hill

Hastings

Botsford

2002

The American Naturalist

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Habitat destruction is a critical factor that affects persistence in several taxa, including Pacific salmon. Salmon are noted for their ability to home to their natal streams for reproduction. Since straying (i.e., spawners reproducing in nonnatal streams) is typically low in salmon, its effects have not been appreciated. In this article, we develop both a general analytical model and a simple simulation model describing structured metapopulations to study how weak connections between subpopulations affect the ability of a species to tolerate habitat destruction and/or declines in habitat quality. Our goals are to develop general principles and to relate these principles to salmon population dynamics. The analytical model describes the dynamics of two density-dependent subpopulations, connected by dispersal, whose growth rates fluctuate in response to environmental and demographic stochasticity. We find that, for moderate levels of environmental variability, small dispersal rates can significantly increase mean extinction times. This effect declines with increasing habitat quality, increasing temporal correlation, and increasing spatial correlation, but it is still significant for realistic parameter values. The simulation model shows there is a threshold rate of dispersal that minimizes extinction probabilities. These results cannot be seen in classical metapopulation models and provide new insights into the rescue effect.

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Assessing covariability among populations in the presence of intraseries correlation: Columbia River spring-summer chinook salmon (Oncorhynchus tshawytscha) stocks

Cited by 27 publications

References 9 publications

Contrasting life-cycle impacts of stream flow on two Chinook salmon populations

Contrasting life-cycle impacts of stream flow on two Chinook salmon populations

Scales of benthic–pelagic coupling and the intensity of species interactions: From recruitment limitation to top-down control

The Effects of Small Dispersal Rates on Extinction Times in Structured Metapopulation Models

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