scholarly journals Diel patterns of foraging and microhabitat use by sympatric rainbow trout and bull trout: implications for adaptive differentiation and instream flow assessment

2021 ◽  
Author(s):  
Sean M. Naman ◽  
Jordan S Rosenfeld ◽  
Alecia S. Lannan
Keyword(s):  
Rainbow Trout ◽  
Habitat Use ◽  
Predation Risk ◽  
Habitat Suitability ◽  
Diel Activity ◽  
Foraging Efficiency ◽  
Bull Trout ◽  
Flow Management ◽  
Habitat Suitability Models ◽  
Trade Offs

Salmonids make flexible and adaptive trade-offs between foraging efficiency and predation risk that result in variable patterns of diel activity and habitat use. However, it remains unclear: (1) how patterns differ among salmonid species; and (2) how this affects the interpretation of habitat suitability models that inform instream flow management. We combined snorkel observations with experimental additions of cover to investigate how predation risk, cover, and bioenergetics affect diel activity and habitat use patterns by sympatric rainbow trout and bull trout in the Skagit River, BC, Canada. Both species foraged primarily at dusk, supporting the well-described trade-off between foraging efficiency and predation risk. However, only rainbow trout responded to cover additions, suggesting that risk tolerance and the nature of foraging-predation risk trade-offs differ between species. Diel shifts in activity and habitat use also substantially altered predictions of habitat suitability models, with potentially large consequences for flow management.

scholarly journals Rain reverses diel activity rhythms in an estuarine teleost

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122363 ◽  
Author(s):  
Nicholas L. Payne ◽  
Dylan E. van der Meulen ◽  
Ruan Gannon ◽  
Jayson M. Semmens ◽  
Iain M. Suthers ◽  
...  
Keyword(s):  
Predation Risk ◽  
Environmental Variability ◽  
Activity Rhythm ◽  
Adaptive Significance ◽  
Diel Activity ◽  
Foraging Efficiency ◽  
Aquatic Animal ◽  
Diurnal Activity ◽  
Activity Rhythms ◽  
Trade Offs

Activity rhythms are ubiquitous in nature, and generally synchronized with the day–night cycle. Several taxa have been shown to switch between nocturnal and diurnal activity in response to environmental variability, and these relatively uncommon switches provide a basis for greater understanding of the mechanisms and adaptive significance of circadian (approx. 24 h) rhythms. Plasticity of activity rhythms has been identified in association with a variety of factors, from changes in predation pressure to an altered nutritional or social status. Here, we report a switch in activity rhythm that is associated with rainfall. Outside periods of rain, the estuarine-associated teleost Acanthopagrus australis was most active and in shallower depths during the day, but this activity and depth pattern was reversed in the days following rain, with diurnality restored as estuarine conductivity and turbidity levels returned to pre-rain levels. Although representing the first example of a rain-induced reversal of activity rhythm in an aquatic animal of which we are aware, our results are consistent with established models on the trade-offs between predation risk and foraging efficiency.

Size-dependent resource limitation and foraging-predation risk trade-offs: growth and habitat use in young arctic char

Oikos ◽  
2004 ◽  
Vol 104 (1) ◽  
pp. 109-121 ◽  
Author(s):  
Pär Byström ◽  
Jens Andersson ◽  
Lennart Persson ◽  
André M. De Roos
Keyword(s):  
Habitat Use ◽  
Predation Risk ◽  
Resource Limitation ◽  
Arctic Char ◽  
Size Dependent ◽  
Trade Offs

Differential use of similar habitat by Harlequin Ducks: trade-offs and implications for identifying critical habitat

2008 ◽  
Vol 86 (5) ◽  
pp. 419-426 ◽  
Author(s):  
Joel P. Heath ◽  
William A. Montevecchi
Keyword(s):  
Predation Risk ◽  
Habitat Suitability ◽  
Management Strategies ◽  
Careful Consideration ◽  
Habitat Characteristics ◽  
Habitat Availability ◽  
Ecological Processes ◽  
Trade Offs ◽  
Harlequin Ducks ◽  
Source And Sink

Interactions between ecological processes operating at different scales are critical aspects of habitat suitability requiring careful consideration in conservation planning. Our previous research indicated that local abundance and demographics of subpopulations of Harlequin Ducks ( Histrionicus histrionicus (L., 1758)), structured in 11 river canyons in northern Labrador, were influenced by predation risk from nest-site-limited raptors. At demographic extremes, where raptors were absent, Harlequin Ducks were stable at high densities, with positive-projected growth, suggesting that they were at carrying capacity and a source of emigrants. In contrast, where raptors were abundant, low density, highly variable populations of ducks approached local extinction in some years, with subsequent increases suggestive of immigration rescue effects. A comparison of resources for Harlequin Ducks indicated no differences in habitat availability among these putative “source” and “sink” subpopulations. In the present study, we used multivariate analysis to identify habitat characteristics important for home-range use within these river canyons and to develop habitat suitability indices (HSI). Despite similar habitat availability, different characteristics were locally important. In a sink where predation risk was high, only danger-reducing habitat characteristics (i.e., overhang vegetation) were identified as important, whereas invertebrates was a predominant characteristic of the source HSI. Despite similar habitat availability, HSI developed in source and sink habitats would, respectively, over- and under-estimate regional habitat availability. Informed conservation and management strategies will therefore require integrating individual trade-offs about predation risk and resources into a multiscale context.

scholarly journals Winter activity patterns of American martens (Martes americana): rejection of the hypothesis of thermal-cost minimization

1997 ◽  
Vol 75 (5) ◽  
pp. 812-816 ◽  
Author(s):  
Gary S. Drew ◽  
John A. Bissonette
Keyword(s):  
Predation Risk ◽  
Cost Minimization ◽  
Activity Patterns ◽  
Martes Americana ◽  
Diel Activity ◽  
Foraging Efficiency ◽  
Behavioral Strategies ◽  
Vulnerability Hypothesis ◽  
Log Linear ◽  
American Martens

Despite their temperate to subarctic geographic range, American martens (Martes americana) possess a thermally inefficient morphology. The lack of morphological adaptations for reducing thermal costs suggests that marten may use behavioral strategies to optimize thermal budgets. During the winters of 1989–1990 and 1990–1991, we radio-collared and monitored the diel activity of 7 martens. A log-linear model suggested that the presence or absence of light was the only factor associated with marten activity patterns (p < 0.001). A regression of the percentage of active fixes on ambient temperature failed to detect an association (b = −4.45, p = 0.084, n = 12). Contents of marten scats suggested that their activity was consistent with the prey-vulnerability hypothesis. While martens must balance multiple life requisites, their activity patterns suggest that they accept increased thermal costs in order to increase foraging efficiency. However, the nocturnal activity of martens during winter was also consistent with the hypothesis that they may be able to limit their own exposure to predation risk. The nocturnal habits of Newfoundland martens in the winter were consistent with the hypothesis of avoidance of predation risk.

scholarly journals Individual variability of wild juvenile Atlantic salmon activity patterns: effect of flow stage, temperature, and habitat use

2013 ◽  
Vol 70 (7) ◽  
pp. 1082-1091 ◽  
Author(s):  
Mathieu L. Roy ◽  
André G. Roy ◽  
James W.A. Grant ◽  
Normand E. Bergeron
Keyword(s):  
Atlantic Salmon ◽  
Habitat Use ◽  
Activity Pattern ◽  
Daily Activity ◽  
Activity Patterns ◽  
Diel Activity ◽  
Large Network ◽  
Lower Velocity ◽  
Trade Offs ◽  
Flow Stage

The magnitude of variation of diel activity patterns and habitat use of wild Atlantic salmon (Salmo salar) parr was examined during the summer and autumn through a gradient of declining temperature. Fish were marked with passive integrated transponders and tracked using a large network of flatbed antennas. High interindividual variability was observed, as some individuals were predominantly nocturnal whereas others frequently changed their daily activity pattern. Overall fish activity decreased with decreasing temperature and increasing flow stage, but most of these changes in daily activity were observed in crepuscular periods. Parr used habitats with lower velocity at night than in the day during the summer, but not in the autumn. Furthermore, there was no difference between day and night habitats for fish that were cathemeral (active both day and night during a given day), so differences between day and night habitats were the result of individuals adopting different activity patterns. These results suggest that habitat interacts with activity pattern, as individuals using suboptimal habitats seem to increase daytime foraging to secure sufficient energy. Temporal and among-fish variability of activity patterns illustrate the dynamic nature of foraging decisions that may partly result from trade-offs experienced at the microhabitat scale.

Landscape-level habitat suitability models for twelve species in southern Missouri

2003 ◽  
Author(s):  
Michael A. Larson ◽  
William D. Dijak ◽  
Frank R. III Thompson ◽  
Joshua J. Millspaugh
Keyword(s):  
Habitat Suitability ◽  
Habitat Suitability Models ◽  
Landscape Level
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