The Role of Terrestrial Invertebrates in Allopatric Brook Trout Headwater Streams in the Central Appalachian Mountains

Webster, Jeremy J.; Hartman, Kyle J.

doi:10.1080/02705060.2005.9664942

Cited by 20 publications

(18 citation statements)

References 26 publications

(40 reference statements)

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“…This suggests that classifying all terrestrial insects into one group as in other salmonid taxonomic diet studies (Forrester et al, 1994;Bridcut & Giller, 1995;Mookerji et al, 2004) may distort the true values of prey importance. One study that did consider terrestrial taxonomic detail (Webster & Hartman, 2005), found that certain terrestrial organisms may score higher in the index of relative importance (IRI) than others. Another study with terrestrial taxonomic detail (Allan, 1981) found that non-native brook trout may specifically target Coleoptera in Colorado.…”

Section: Discussionmentioning

confidence: 99%

“…Although considerable literature has examined trout diet patterns, many studies considered only select seasons and most categorized all terrestrial prey taxa into one group (Cada et al, 1987;Thonney & Gibson, 1989;Forrester et al, 1994;Bridcut & Giller, 1995;Mookerji et al, 2004). However, when the taxonomic detail of terrestrial organisms is considered, studies have found that some taxa may be of particular importance while others are relatively negligible as energetic input to aquatic ecosystems (Wipfli & Gregovich, 2002) or fish diet (Wipfli, 1997;Webster & Hartman, 2005).…”

Section: Introductionmentioning

confidence: 98%

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Identification of critical prey items to Appalachian brook trout (Salvelinus fontinalis) with emphasis on terrestrial organisms

Utz

Hartman²

2006

Hydrobiologia

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Brook trout (Salvelinus fontinalis) in Appalachia experience prolonged periods of poor feeding conditions, particularly during summer and fall. To determine which prey organisms are important in sustaining brook trout populations, we monitored the feeding patterns of a population of brook trout over the course of 2 years with an emphasis on seasonal change. We employed a bioenergetics model to estimate whether or not each fish had obtained enough energy to meet daily metabolic demand. As a result, qualitative comparisons between fish feeding above maintenance ration (successfully feeding fish) and fish feeding below maintenance ration (unsuccessfully feeding fish) were possible. With the exception of winter, brook trout derived significantly more energy from terrestrial organisms than aquatic organisms. During each season, successfully feeding brook trout fed on greater proportions of specific prey types.Terrestrial Coleoptera and Lepidoptera consistently proved to be important prey during warmer seasons, while large organisms such as vertebrates and crayfish appeared to be important during winter. Our findings suggest that terrestrial organisms are more important than aquatic organisms in sustaining brook trout populations. Further, certain large and abundant terrestrial taxa are critical in providing energy to brook trout.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Identification of critical prey items to Appalachian brook trout (Salvelinus fontinalis) with emphasis on terrestrial organisms

Utz

Hartman²

2006

Hydrobiologia

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“…The contribution of this potential prey is however highly seasonal, with a relatively low input in spring and autumn and a high input in late summer (Bridcut 2000;Nakano & Murakami 2001). Dietary studies of salmonids have revealed that during summer, terrestrial invertebrates may exceed 50% of the total diet biomass (Zadorina 1988;Bridcut & Giller 1995;Wipfli 1997;Nakano et al 1999a,b;Webster & Hartman 2005). The terrestrial resource is presumably quite important for salmonids as the seasonal peak in invertebrate input often corresponds with a parallel decrease in benthic invertebrate abundance (Hynes 1970;Cloe & Garman 1996;Dineen et al 2007b;Er} os et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Functional response and size‐dependent foraging on aquatic and terrestrial prey by brown trout (Salmo trutta L.)

Gustafsson

Bergman

Greenberg

2010

Ecology of Freshwater Fish

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Terrestrial invertebrate subsidies are believed to be important energy sources for drift-feeding salmonids. Despite this, size-specific use of and efficiency in procuring this resource have not been studied to any great extent. Therefore, we measured the functional responses of three size classes of wild brown trout Salmo trutta (0+, 1+ and ‡2+) when fed either benthic-(Gammarus sp.) or surface-drifting prey (Musca domestica) in laboratory experiments. To test for size-specific prey preferences, both benthic and surface prey were presented simultaneously by presenting the fish with a constant density of benthic prey and a variable density of surface prey. The results showed that the functional response of 0+ trout differed significantly from the larger size classes, with 0+ fish having the lowest capture rates. Capture rates did not differ significantly between prey types. In experiments when both prey items were presented simultaneously, capture rate differed significantly between size classes, with larger trout having higher capture rates than smaller trout. However, capture rates within each size class did not change with prey density or prey composition. The two-prey experiments also showed that 1+ trout ate significantly more surface-drifting prey than 0+ trout. In contrast, there was no difference between 0+ and ‡2+ trout. Analyses of the vertical position of the fish in the water column corroborated size-specific foraging results: larger trout remained in the upper part of the water column between attacks on surface prey more often than smaller trout, which tended to seek refuge at the bottom between attacks. These size-specific differences in foraging and vertical position suggest that larger trout may be able to use surface-drifting prey to a greater extent than smaller conspecifics.

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“…Parallel with studies reporting that forested riparian zones generally have higher inputs of falling terrestrial invertebrates than unforested riparian zones [21],[22], other descriptive studies have reported that during some parts of the year terrestrial invertebrates are frequently consumed by salmonids and may contribute >50% of total food intake [13]–[20],[23]. Terrestrial invertebrates may be beneficial for stream fish for several reasons.…”

Section: Introductionmentioning

confidence: 96%

Forest-Stream Linkages: Effects of Terrestrial Invertebrate Input and Light on Diet and Growth of Brown Trout (Salmo trutta) in a Boreal Forest Stream

et al. 2012

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Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2×2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta) and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-month-long experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.

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The Role of Terrestrial Invertebrates in Allopatric Brook Trout Headwater Streams in the Central Appalachian Mountains

Cited by 20 publications

References 26 publications

Identification of critical prey items to Appalachian brook trout (Salvelinus fontinalis) with emphasis on terrestrial organisms

Identification of critical prey items to Appalachian brook trout (Salvelinus fontinalis) with emphasis on terrestrial organisms

Functional response and size‐dependent foraging on aquatic and terrestrial prey by brown trout (Salmo trutta L.)

Forest-Stream Linkages: Effects of Terrestrial Invertebrate Input and Light on Diet and Growth of Brown Trout (Salmo trutta) in a Boreal Forest Stream

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