2002
Finlay, Jacques C.; Khandwala, Sapna; Power, Mary E.
Spatial scales of carbon flow in a river food web Journal Article
In: Ecology, vol. 83, no. 7, pp. 1845-1859, 2002.
Abstract | Links | BibTeX | Tags: cannibalism, carbon and nitrogen stable-isotope ratios, carbon flow, Oncorhynchus mykiss, river food webs, scraper and collector-gatherer (SCG) taxa, spatial scale, steelhead trout, terrestrial detritus, trophic structure
@article{Finlay2002,
title = {Spatial scales of carbon flow in a river food web},
author = {Jacques C. Finlay and Sapna Khandwala and Mary E. Power},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Spatial-scales-of-energy-flow-in-food-webs-of-the-South-Fork-Eel-River_Finlay_2002.pdf},
doi = {10.2307/3071769},
year = {2002},
date = {2002-00-00},
journal = {Ecology},
volume = {83},
number = {7},
pages = {1845-1859},
abstract = {Spatial extents of food webs that support stream and river consumers are largely unknown, but such information is essential for basic understanding and management of lotic ecosystems. We used predictable variation in algal δ13C with water velocity, and measurements of consumer δ13C and δ15N to examine carbon flow and trophic structure in food webs of the South Fork Eel River in Northern California. Analyses of δ13C showed that the most abundant macroinvertebrate groups (collector-gatherers and scrapers) relied on algae from local sources within their riffle or shallow pool habitats. In contrast, filter-feeding invertebrates in riffles relied in part on algal production derived from upstream shallow pools. Riffle invertebrate predators also relied in part on consumers of pool-derived algal carbon. One abundant taxon drifting from shallow pools and riffles (baetid mayflies) relied on algal production derived from the habitats from which they dispersed. The trophic linkage from pool algae to riffle invertebrate predators was thus mediated through either predation on pool herbivores dispersing into riffles, or on filter feeders. Algal production in shallow pool habitats dominated the resource base of vertebrate predators in all habitats at the end of the summer. We could not distinguish between the trophic roles of riffle algae and terrestrial detritus, but both carbon sources appeared to play minor roles for vertebrate consumers. In shallow pools, small vertebrates, including three-spined stickleback (Gasterosteus aculeatus), roach (Hesperoleucas symmetricus), and rough-skinned newts (Taricha granulosa), relied on invertebrate prey derived from local pool habitats. During the most productive summer period, growth of all size classes of steelhead and resident rainbow trout (Oncorhynchus mykiss) in all habitats (shallow pools, riffles, and deep unproductive pools) was largely derived from algal production in shallow pools. Preliminary data suggest that the strong role of shallow pool algae in riffle steelhead growth during summer periods was due to drift of pool invertebrates to riffles, rather than movement of riffle trout. Data for δ15N showed that resident rainbow trout (25-33 cm standard length) in deep pools preyed upon small size classes of juvenile steelhead that were most often found in riffles or shallow pools. While many invertebrate consumers relied primarily on algal production derived from local habitats, our study shows that growth of top predators in the river is strongly linked to food webs in adjacent habitats. These results suggest a key role for emigration of aquatic prey in determining carbon flow to top predators.},
keywords = {cannibalism, carbon and nitrogen stable-isotope ratios, carbon flow, Oncorhynchus mykiss, river food webs, scraper and collector-gatherer (SCG) taxa, spatial scale, steelhead trout, terrestrial detritus, trophic structure},
pubstate = {published},
tppubtype = {article}
}
Spatial extents of food webs that support stream and river consumers are largely unknown, but such information is essential for basic understanding and management of lotic ecosystems. We used predictable variation in algal δ13C with water velocity, and measurements of consumer δ13C and δ15N to examine carbon flow and trophic structure in food webs of the South Fork Eel River in Northern California. Analyses of δ13C showed that the most abundant macroinvertebrate groups (collector-gatherers and scrapers) relied on algae from local sources within their riffle or shallow pool habitats. In contrast, filter-feeding invertebrates in riffles relied in part on algal production derived from upstream shallow pools. Riffle invertebrate predators also relied in part on consumers of pool-derived algal carbon. One abundant taxon drifting from shallow pools and riffles (baetid mayflies) relied on algal production derived from the habitats from which they dispersed. The trophic linkage from pool algae to riffle invertebrate predators was thus mediated through either predation on pool herbivores dispersing into riffles, or on filter feeders. Algal production in shallow pool habitats dominated the resource base of vertebrate predators in all habitats at the end of the summer. We could not distinguish between the trophic roles of riffle algae and terrestrial detritus, but both carbon sources appeared to play minor roles for vertebrate consumers. In shallow pools, small vertebrates, including three-spined stickleback (Gasterosteus aculeatus), roach (Hesperoleucas symmetricus), and rough-skinned newts (Taricha granulosa), relied on invertebrate prey derived from local pool habitats. During the most productive summer period, growth of all size classes of steelhead and resident rainbow trout (Oncorhynchus mykiss) in all habitats (shallow pools, riffles, and deep unproductive pools) was largely derived from algal production in shallow pools. Preliminary data suggest that the strong role of shallow pool algae in riffle steelhead growth during summer periods was due to drift of pool invertebrates to riffles, rather than movement of riffle trout. Data for δ15N showed that resident rainbow trout (25-33 cm standard length) in deep pools preyed upon small size classes of juvenile steelhead that were most often found in riffles or shallow pools. While many invertebrate consumers relied primarily on algal production derived from local habitats, our study shows that growth of top predators in the river is strongly linked to food webs in adjacent habitats. These results suggest a key role for emigration of aquatic prey in determining carbon flow to top predators.
2001
Finlay, Jacques C.; Power, Mary E.
In: Technical Completion Report, vol. UCAL-WRC-W-906, 2001.
Abstract | Links | BibTeX | Tags: cannibalism, Carbon and nitrogen stable isotope ratios, energy flow, Oncorhynchus mykiss, river food webs, river-watershed exchange, spatial scale, steelhead trout, terrestrial detritus, trophic structure
@article{Power2001,
title = {Carbon isotope signatures and spatial scales of energy flow in food webs supporting salmonids in food webs supporting salmonids in Northern California rivers},
author = {Jacques C. Finlay and Mary E. Power},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/eScholarship-UC-item-79t2s4f8.pdf},
year = {2001},
date = {2001-05-01},
journal = {Technical Completion Report},
volume = {UCAL-WRC-W-906},
abstract = {Spatial scales of the food webs that support the growth of juvenile salmonids in California rivers are largely unknown, but such information is essential for management of flows, species, and other ecosystem factors influencing salmonid production. Our project objectives were:
1. to determine whether predictable variation in algal d13C with water velocity, and measurements of consumer d13C and d15N could be used to examine energy flow and trophic structure in food webs of the South Fork Eel River, and other salmon-bearing streams in Northern California, and
2. to provide this information as a basis for examining how changes in access to energy sources following river regulation or invasions of exotic species might influence the access of various web members, including salmonids, to these sources.},
keywords = {cannibalism, Carbon and nitrogen stable isotope ratios, energy flow, Oncorhynchus mykiss, river food webs, river-watershed exchange, spatial scale, steelhead trout, terrestrial detritus, trophic structure},
pubstate = {published},
tppubtype = {article}
}
Spatial scales of the food webs that support the growth of juvenile salmonids in California rivers are largely unknown, but such information is essential for management of flows, species, and other ecosystem factors influencing salmonid production. Our project objectives were:
1. to determine whether predictable variation in algal d13C with water velocity, and measurements of consumer d13C and d15N could be used to examine energy flow and trophic structure in food webs of the South Fork Eel River, and other salmon-bearing streams in Northern California, and
2. to provide this information as a basis for examining how changes in access to energy sources following river regulation or invasions of exotic species might influence the access of various web members, including salmonids, to these sources.
1. to determine whether predictable variation in algal d13C with water velocity, and measurements of consumer d13C and d15N could be used to examine energy flow and trophic structure in food webs of the South Fork Eel River, and other salmon-bearing streams in Northern California, and
2. to provide this information as a basis for examining how changes in access to energy sources following river regulation or invasions of exotic species might influence the access of various web members, including salmonids, to these sources.
1997
Gresens, Susan E.
Interactive effects of diet and thermal regime on growth of the midge Pseudochironomus richardsoni Malloch Journal Article
In: Freshwater Biology, vol. 38, no. 2, pp. 365-373, 1997, ISSN: 0046-5070.
Abstract | Links | BibTeX | Tags: Blackwater River, diptera, larval chironomidae, rapid growth, Riparian, river food webs, SECONDARY PRODUCTION, size, STREAM, temperature
@article{Gresens1997,
title = {Interactive effects of diet and thermal regime on growth of the midge Pseudochironomus richardsoni Malloch},
author = {Susan E. Gresens},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Gresens_FreshwaterBiology1997.pdf},
doi = {10.1046/j.1365-2427.1997.00248.x},
issn = {0046-5070},
year = {1997},
date = {1997-10-00},
journal = {Freshwater Biology},
volume = {38},
number = {2},
pages = {365-373},
abstract = {1. Larvae of Pseudochironomus richardsoni were reared to pupation in individual enclosures, in one of three thermal habitats in a northern California stream. The average temperature range in cold seeps was 15-21 degrees C, while the main channel ranged from 20 to 27 degrees C, and side pools ranged from 18 to 33 degrees C. Diet consisted of either diatoms or algal detritus.
2. Specific growth rate ranged from 0.057 to 0.267 day(-1). Specific growth and developmental rates were highest on a diatom diet, and increased with temperature. Regressions of growth rate on mean microsite temperature were also significantly altered by diet. Differences in specific growth rate due to diet are magnified at higher temperatures.
3. Pupae reared on diatoms were larger than those reared on detritus. The mass of pupae reared on detritus decreased with increasing temperature. However, there was no significant relationship between pupal mass and temperature for larvae reared on diatoms.
4. The combined effects of food quality and thermal environment on growth of the midge P. richardsoni are significantly different from the independent effects of diet and temperature. Interactive effects of food quality and temperature may influence the contribution of certain aquatic habitats (algal mats) to invertebrate secondary production.},
keywords = {Blackwater River, diptera, larval chironomidae, rapid growth, Riparian, river food webs, SECONDARY PRODUCTION, size, STREAM, temperature},
pubstate = {published},
tppubtype = {article}
}
1. Larvae of Pseudochironomus richardsoni were reared to pupation in individual enclosures, in one of three thermal habitats in a northern California stream. The average temperature range in cold seeps was 15-21 degrees C, while the main channel ranged from 20 to 27 degrees C, and side pools ranged from 18 to 33 degrees C. Diet consisted of either diatoms or algal detritus.
2. Specific growth rate ranged from 0.057 to 0.267 day(-1). Specific growth and developmental rates were highest on a diatom diet, and increased with temperature. Regressions of growth rate on mean microsite temperature were also significantly altered by diet. Differences in specific growth rate due to diet are magnified at higher temperatures.
3. Pupae reared on diatoms were larger than those reared on detritus. The mass of pupae reared on detritus decreased with increasing temperature. However, there was no significant relationship between pupal mass and temperature for larvae reared on diatoms.
4. The combined effects of food quality and thermal environment on growth of the midge P. richardsoni are significantly different from the independent effects of diet and temperature. Interactive effects of food quality and temperature may influence the contribution of certain aquatic habitats (algal mats) to invertebrate secondary production.
2. Specific growth rate ranged from 0.057 to 0.267 day(-1). Specific growth and developmental rates were highest on a diatom diet, and increased with temperature. Regressions of growth rate on mean microsite temperature were also significantly altered by diet. Differences in specific growth rate due to diet are magnified at higher temperatures.
3. Pupae reared on diatoms were larger than those reared on detritus. The mass of pupae reared on detritus decreased with increasing temperature. However, there was no significant relationship between pupal mass and temperature for larvae reared on diatoms.
4. The combined effects of food quality and thermal environment on growth of the midge P. richardsoni are significantly different from the independent effects of diet and temperature. Interactive effects of food quality and temperature may influence the contribution of certain aquatic habitats (algal mats) to invertebrate secondary production.
1996
Wottoon, TJ; Parker, MS; Power, ME
Effects of Disturbance on River Food Webs Journal Article
In: Science, vol. 273, iss. 5281, pp. 1558-1561, 1996, ISBN: 0036-8075, 1095-9203.
Abstract | Links | BibTeX | Tags: river food webs
@article{Wottoon1996,
title = {Effects of Disturbance on River Food Webs},
author = {TJ Wottoon and MS Parker and ME Power},
doi = {10.1126/science.273.5281.1558},
isbn = {0036-8075, 1095-9203},
year = {1996},
date = {1996-09-13},
urldate = {1996-09-13},
journal = {Science},
volume = {273},
issue = {5281},
pages = {1558-1561},
abstract = {A multitrophic model integrating the effects of flooding disturbance and food web interactions in rivers predicted that removing floods would cause increases of predator-resistant grazing insects, which would divert energy away from the food chain leading to predatory fish. Experimental manipulations of predator-resistant grazers and top predators, and large-scale comparisons of regulated and unregulated rivers, verified the model predictions. Thus, multitrophic models can successfully synthesize a variety of ecological processes, and conservation programs may benefit by taking a food web perspective instead of concentrating on a single species.},
keywords = {river food webs},
pubstate = {published},
tppubtype = {article}
}
A multitrophic model integrating the effects of flooding disturbance and food web interactions in rivers predicted that removing floods would cause increases of predator-resistant grazing insects, which would divert energy away from the food chain leading to predatory fish. Experimental manipulations of predator-resistant grazers and top predators, and large-scale comparisons of regulated and unregulated rivers, verified the model predictions. Thus, multitrophic models can successfully synthesize a variety of ecological processes, and conservation programs may benefit by taking a food web perspective instead of concentrating on a single species.
Power, Mary E.; Tilman, David; Estes, James A.; Menge, Bruce A.; Bond, L. Scott Mills William J.; Daily, Gretchen; Castilla, Juan Carlos; Lubchenco, Jane; Paine, Robert T.
Challenges in the quest for keystones Journal Article
In: BioScience, vol. 46, no. 8, pp. 609-620, 1996, ISSN: 0006-3568, (File size exceeds Angelo maximum; see the stable link attached.).
Links | BibTeX | Tags: biological invasions, fish community, interaction strength, Lake Michigan, mass mortality, pocket gophers, river food webs, rocky intertidal community, sea otter predation, species concept
@article{Power1996b,
title = {Challenges in the quest for keystones},
author = {Mary E. Power and David Tilman and James A. Estes and Bruce A. Menge and L. Scott Mills William J. Bond and Gretchen Daily and Juan Carlos Castilla and Jane Lubchenco and Robert T. Paine},
url = {http://www.jstor.org/stable/1312990},
doi = {10.2307/1312990},
issn = {0006-3568},
year = {1996},
date = {1996-09-00},
journal = {BioScience},
volume = {46},
number = {8},
pages = {609-620},
note = {File size exceeds Angelo maximum; see the stable link attached.},
keywords = {biological invasions, fish community, interaction strength, Lake Michigan, mass mortality, pocket gophers, river food webs, rocky intertidal community, sea otter predation, species concept},
pubstate = {published},
tppubtype = {article}
}
1990
Power, M. E.
Effects of fish in river food webs Journal Article
In: Science, vol. 250, pp. 411-415, 1990.
Abstract | Links | BibTeX | Tags: fish, river food webs
@article{Power1990b,
title = {Effects of fish in river food webs},
author = {M. E. Power},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Power_1990_Science.pdf},
year = {1990},
date = {1990-04-10},
journal = {Science},
volume = {250},
pages = {411-415},
abstract = {Experimental manipulations offish in a Northern California river during summer base flow reveal that they have large effects on predators, herbivores, and plants in river food webs. California roach and juvenile steelhead consume predatory insects and fishfry, which feed on algivorous chironomid larvae. In the presence offish, filamentous green algae are reduced to low, prostrate webs, infested with chironomids. When the absence of large fish releases smaller predators that suppress chironomids, algal biomass is higher, and tall upright algal turfs become covered with diatoms and cyanobacteria. These manipulations provide evidence that the Hairston, Smith, Slobodkin-Fretwell theory of trophic control, which predicts that plants will be alternately limited by resources or herbivores in food webs with odd and even numbers of trophic levels, has application to river communities.},
keywords = {fish, river food webs},
pubstate = {published},
tppubtype = {article}
}
Experimental manipulations offish in a Northern California river during summer base flow reveal that they have large effects on predators, herbivores, and plants in river food webs. California roach and juvenile steelhead consume predatory insects and fishfry, which feed on algivorous chironomid larvae. In the presence offish, filamentous green algae are reduced to low, prostrate webs, infested with chironomids. When the absence of large fish releases smaller predators that suppress chironomids, algal biomass is higher, and tall upright algal turfs become covered with diatoms and cyanobacteria. These manipulations provide evidence that the Hairston, Smith, Slobodkin-Fretwell theory of trophic control, which predicts that plants will be alternately limited by resources or herbivores in food webs with odd and even numbers of trophic levels, has application to river communities.