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algae biodiversity biological invasions birds California competition disturbance ecology epiphytes fish food web food webs freshwater mussels geomorphology indirect effects interaction strength LiDAR mammals nutrients periphyton plants Rana boylii Riparian river food webs rivers species list stable isotope steelhead trout streams trophic cascades
2004 |
Kotanen, Peter M Revegetation following Soil Disturbance and Invasion in a Californian Meadow: a 10-year History of Recovery Journal Article Biological Invasions, 6 (2), pp. 245–254, 2004, ISSN: 1573-1464. Abstract | Links | BibTeX | Tags: aliens, disturbance, exotics, feral pigs, grasslands, invasions, restoration, succession @article{Kotanen2004, title = {Revegetation following Soil Disturbance and Invasion in a Californian Meadow: a 10-year History of Recovery}, author = {Peter M. Kotanen}, url = {http://angelo.berkeley.edu/wp-content/uploads/Revegetation-following-Soil-Disturbance-and-Invasion-in-a-Californian-Meadow-a-10-year-History-of-Recovery-Biological-Invasions_Kotanen1.pdf}, doi = {10.1023/B:BINV.0000022145.03215.4f}, issn = {1573-1464}, year = {2004}, date = {2004-00-00}, journal = {Biological Invasions}, volume = {6}, number = {2}, pages = {245–254}, abstract = {Disturbance is necessary for the regeneration of many native plant species, but can also facilitate biological invasions. As a result, disturbance can play complex roles in vulnerable habitats such as remnant Californian perennial grasslands. To investigate these conflicts, plots in a northern Californian coastal grassland were experimentally disturbed in the winter of 1990-1991; these plots differed in the area and intensity (depth) of the soil disturbance applied. When these plots were revisited after 10 growing seasons, patterns of revegetation differed significantly from those observed early in recolonization (0-3 years). At the earlier samplings, exotic annual grasses rapidly increased in most disturbance types. After 10 years, these exotic annuals had retreated from the depth experiment, which had recovered to a vegetation dominated by native perennials in all but the most severely disturbed plots. In contrast, although differences between control and disturbed plots also disappeared in the area experiment, the average abundance of aliens did not decline substantially relative to 1993 levels, especially in larger disturbances. Nonetheless, populations of aliens remained small compared to the peak populations in the depth experiment, probably reflecting wetter soils at the site used for the area experiment. These results differ from those of other recent studies of soil disturbance in coastal Californian ecosystems, which indicate disturbance may result in the permanent replacement of native perennial vegetation by dense populations of exotic annual grasses. This difference may reflect the high resilience of northern coastal grasslands as well as the scale of disturbances considered by different studies.}, keywords = {aliens, disturbance, exotics, feral pigs, grasslands, invasions, restoration, succession}, pubstate = {published}, tppubtype = {article} } Disturbance is necessary for the regeneration of many native plant species, but can also facilitate biological invasions. As a result, disturbance can play complex roles in vulnerable habitats such as remnant Californian perennial grasslands. To investigate these conflicts, plots in a northern Californian coastal grassland were experimentally disturbed in the winter of 1990-1991; these plots differed in the area and intensity (depth) of the soil disturbance applied. When these plots were revisited after 10 growing seasons, patterns of revegetation differed significantly from those observed early in recolonization (0-3 years). At the earlier samplings, exotic annual grasses rapidly increased in most disturbance types. After 10 years, these exotic annuals had retreated from the depth experiment, which had recovered to a vegetation dominated by native perennials in all but the most severely disturbed plots. In contrast, although differences between control and disturbed plots also disappeared in the area experiment, the average abundance of aliens did not decline substantially relative to 1993 levels, especially in larger disturbances. Nonetheless, populations of aliens remained small compared to the peak populations in the depth experiment, probably reflecting wetter soils at the site used for the area experiment. These results differ from those of other recent studies of soil disturbance in coastal Californian ecosystems, which indicate disturbance may result in the permanent replacement of native perennial vegetation by dense populations of exotic annual grasses. This difference may reflect the high resilience of northern coastal grasslands as well as the scale of disturbances considered by different studies. |
2003 |
Levine, Jonathan M A patch modeling approach to the community-level consequences of directional dispersal Journal Article Ecology, 84 (5), pp. 1215-1224, 2003. Abstract | Links | BibTeX | Tags: coexistence, community, directional dispersal, disturbance, patch model, river, species diversity @article{Levine2003, title = {A patch modeling approach to the community-level consequences of directional dispersal}, author = {Jonathan M. Levine}, url = {http://angelo.berkeley.edu/wp-content/uploads/A-PATCH-MODELING-APPROACH-TO-THE-COMMUNITY-LEVEL-CONSEQUENCES-OF-DIRECTIONAL-DISPERSAL_Levine_2003.pdf}, doi = {http://dx.doi.org/10.1890/0012-9658(2003)084[1215:APMATT]2.0.CO;2}, year = {2003}, date = {2003-05-00}, journal = {Ecology}, volume = {84}, number = {5}, pages = {1215-1224}, abstract = {Although plants and other sessile organisms often disperse in a prevailing direction, the ecological consequences of this are poorly understood. To explore patterns of plant diversity similar to those found in a California river system, I modeled perennial plant populations and communities occurring in a linear series of neighborhoods connected by dispersal, where dispersal occurs in a prevailing downstream direction. Simulations demonstrated that population size and species diversity correlated with dispersal and increased downstream, but only if fecundity and death rates were such that neighborhoods within the system depended on external propagule input for their persistence. Highly effective downstream dispersal and some upstream dispersal were also required. If these demographic and dispersal criteria were met, communities with intense competition and inhibition still developed downstream increases in diversity. Additionally, in such systems, directional dispersal could favor species coexistence since upstream neighborhoods provided a refuge for inferior competitors. The demographic and dispersal criteria were relaxed for systems recovering from scattered source populations following disturbance. I conclude that directional dispersal may be a key determinant of species coexistence and patterns of diversity in severely propagule-limited systems.}, keywords = {coexistence, community, directional dispersal, disturbance, patch model, river, species diversity}, pubstate = {published}, tppubtype = {article} } Although plants and other sessile organisms often disperse in a prevailing direction, the ecological consequences of this are poorly understood. To explore patterns of plant diversity similar to those found in a California river system, I modeled perennial plant populations and communities occurring in a linear series of neighborhoods connected by dispersal, where dispersal occurs in a prevailing downstream direction. Simulations demonstrated that population size and species diversity correlated with dispersal and increased downstream, but only if fecundity and death rates were such that neighborhoods within the system depended on external propagule input for their persistence. Highly effective downstream dispersal and some upstream dispersal were also required. If these demographic and dispersal criteria were met, communities with intense competition and inhibition still developed downstream increases in diversity. Additionally, in such systems, directional dispersal could favor species coexistence since upstream neighborhoods provided a refuge for inferior competitors. The demographic and dispersal criteria were relaxed for systems recovering from scattered source populations following disturbance. I conclude that directional dispersal may be a key determinant of species coexistence and patterns of diversity in severely propagule-limited systems. |
2001 |
Hunter, John C; Barbour, Michael G Through-growth by Pseudotsuga menziesii: A mechanism for change in forest composition without canopy gaps Journal Article Journal of Vegetation Science, 12 (4), pp. 445-452, 2001, ISSN: 1100-9233. Abstract | Links | BibTeX | Tags: acer-saccharum, competition, disturbance, light, morphology, northern California, patterns, recruitment, stands, trees @article{Hunter2001, title = {Through-growth by Pseudotsuga menziesii: A mechanism for change in forest composition without canopy gaps}, author = {John C. Hunter and Michael G. Barbour}, url = {http://angelo.berkeley.edu/wp-content/uploads/Through-Growth-by-Pseudotsuga-menziesii-A-Mechanism-for-Change-in-Forest-Composition-without-Canopy-Gaps_Hunter_Barbour_2001.pdf}, doi = {10.2307/3236996}, issn = {1100-9233}, year = {2001}, date = {2001-08-00}, journal = {Journal of Vegetation Science}, volume = {12}, number = {4}, pages = {445-452}, abstract = {exception. In California's Pseudotsuga-mixed hardwood forests, crowns of Pseudotsuga menziesii (Douglas fir) are within those of angiosperm trees (Arbutus menziesii and Quercus species). In the forests we examined, every Pseudotsuga was younger and all but one were growing more rapidly in girth than the Arbutus or Quercus whose crown it had penetrated. Furthermore, as saplings. the Pseudotsuga had grown at rates between those of suppressed saplings and canopy dominants, The recruitment of emergent Pseudotsuga substantially alters these canopies because of the large size Pseudotsuga attains. Given the density of Pseudotsuga growing in canopy crowns, such recruitment is likely. As a mechanism of recruitment, this through-growth differs from gap recruitment in that the turnover of canopy trees is determined by an understory species' growth rate rather than the overstory species' longevity, and community attributes may change rapidly by replacement of canopy dominants with a dissimilar species. Pseudotsuga could grow through the canopy because of its greater potential height (> 60m vs. 20-40m for the angio-perms). narrower crown and its branches suffering less mechanical damage than those of the angiosperms. In general, resource levels in the understory, canopy height, and interspecific differences in maximum height and crown architecture all influence the likelihood of through-growth. Therefore, for vegetation types whose dominants differ substantially in growth form, through-growth may be a mechanism for rapid ecosystem change.}, keywords = {acer-saccharum, competition, disturbance, light, morphology, northern California, patterns, recruitment, stands, trees}, pubstate = {published}, tppubtype = {article} } exception. In California's Pseudotsuga-mixed hardwood forests, crowns of Pseudotsuga menziesii (Douglas fir) are within those of angiosperm trees (Arbutus menziesii and Quercus species). In the forests we examined, every Pseudotsuga was younger and all but one were growing more rapidly in girth than the Arbutus or Quercus whose crown it had penetrated. Furthermore, as saplings. the Pseudotsuga had grown at rates between those of suppressed saplings and canopy dominants, The recruitment of emergent Pseudotsuga substantially alters these canopies because of the large size Pseudotsuga attains. Given the density of Pseudotsuga growing in canopy crowns, such recruitment is likely. As a mechanism of recruitment, this through-growth differs from gap recruitment in that the turnover of canopy trees is determined by an understory species' growth rate rather than the overstory species' longevity, and community attributes may change rapidly by replacement of canopy dominants with a dissimilar species. Pseudotsuga could grow through the canopy because of its greater potential height (> 60m vs. 20-40m for the angio-perms). narrower crown and its branches suffering less mechanical damage than those of the angiosperms. In general, resource levels in the understory, canopy height, and interspecific differences in maximum height and crown architecture all influence the likelihood of through-growth. Therefore, for vegetation types whose dominants differ substantially in growth form, through-growth may be a mechanism for rapid ecosystem change. |
d'Antonio, Carla; Levine, Jonathan; Thomsen, Meredith Ecosystem resistance to invasion and the role of propagule supply: a California perspective Journal Article International Journal of Mediterranean Ecology, 27 , pp. 233-245, 2001. Abstract | Links | BibTeX | Tags: alien species, competition, disturbance, exotic invaders, non-indigenous plants. @article{d'Antonio2001, title = {Ecosystem resistance to invasion and the role of propagule supply: a California perspective}, author = {Carla d'Antonio and Jonathan Levine and Meredith Thomsen}, url = {http://angelo.berkeley.edu/wp-content/uploads/dantonio_levine_thomsen_2001.pdf}, year = {2001}, date = {2001-00-00}, journal = {International Journal of Mediterranean Ecology}, volume = {27}, pages = {233-245}, abstract = {The concept of ecological resistance includes both abiotic and biotic features of a recipient environment that influence the success of propagules of a species that has not previously occurred on a site. Despite broad interest in this topic by ecologists and land managers, we lack an understanding of what factors contribute to ecological resistance and how processes influencing resistance interact with the supply of propagules to determine invasion success. Here we present a simple conceptual framework for examining how variation in propagule supply should interact with ecosystem resistance to influence the rate at which exotic invaders enter a habitat. We suggest that when resistance is low, it takes very few propagules for an invader to become established and that rates of invasion will be fast regardless of propagule supply. As resistance increases, however, it takes proportionally more propagules for the invader to establish. When resistance is high invasion will occur only when propagule pressure is high or when invaders themselves can alter resistance as they get a toehold in the community. When resistance is controlled largely by biotic factors we believe that it can be overcome by high rates of propagule supply even if initially appears to be strong, because over space and time biological sources of resistance are likely to be variable allowing windows when a site has moved to a region of the propagule supply axis where many fewer propagules are required for invasion to occur. By contrast, strong abiotic resistance is less likely to be overwhelmed by high propagule pressure and if determined largely by soil factors, is likely to be relatively constant over space and time. We also suggest, that some invaders of harsh environments are successful because of their own ability to modify abiotic conditions thus decreasing the number of propagules needed to promote further invasion. We review examples of resistance in California plant communities and where possible show how resistance interacts with propagule supply. Overall, we found very few studies that measure or consider the role of propagule supply and how it interacts with resistance factors and we believe that such studies are badly needed if we are to advance our understanding of controls over biological invasion.}, keywords = {alien species, competition, disturbance, exotic invaders, non-indigenous plants.}, pubstate = {published}, tppubtype = {article} } The concept of ecological resistance includes both abiotic and biotic features of a recipient environment that influence the success of propagules of a species that has not previously occurred on a site. Despite broad interest in this topic by ecologists and land managers, we lack an understanding of what factors contribute to ecological resistance and how processes influencing resistance interact with the supply of propagules to determine invasion success. Here we present a simple conceptual framework for examining how variation in propagule supply should interact with ecosystem resistance to influence the rate at which exotic invaders enter a habitat. We suggest that when resistance is low, it takes very few propagules for an invader to become established and that rates of invasion will be fast regardless of propagule supply. As resistance increases, however, it takes proportionally more propagules for the invader to establish. When resistance is high invasion will occur only when propagule pressure is high or when invaders themselves can alter resistance as they get a toehold in the community. When resistance is controlled largely by biotic factors we believe that it can be overcome by high rates of propagule supply even if initially appears to be strong, because over space and time biological sources of resistance are likely to be variable allowing windows when a site has moved to a region of the propagule supply axis where many fewer propagules are required for invasion to occur. By contrast, strong abiotic resistance is less likely to be overwhelmed by high propagule pressure and if determined largely by soil factors, is likely to be relatively constant over space and time. We also suggest, that some invaders of harsh environments are successful because of their own ability to modify abiotic conditions thus decreasing the number of propagules needed to promote further invasion. We review examples of resistance in California plant communities and where possible show how resistance interacts with propagule supply. Overall, we found very few studies that measure or consider the role of propagule supply and how it interacts with resistance factors and we believe that such studies are badly needed if we are to advance our understanding of controls over biological invasion. |
1999 |
Bergey, Elizabeth A Crevices as refugia for stream diatoms: Effect of crevice size on abraded substrates Journal Article Limnology and Oceanography, 44 (6), pp. 1522-1529, 1999, ISSN: 0024-3590, (Note that the file size exceeds the maximum allowable for the Angelo database. Please see the attached stable URL for a link to the PDF.). Abstract | Links | BibTeX | Tags: algal communities, colonization, disturbance, habitat structure, marine-invertebrates, New England, rocky intertidal community, species-diversity, tidal community, upland stream @article{Bergey1999, title = {Crevices as refugia for stream diatoms: Effect of crevice size on abraded substrates}, author = {Elizabeth A. Bergey}, editor = {ROCKY INTERTIDAL COMMUNITY; MARINE-INVERTEBRATES; ALGAL COMMUNITIES; SPECIES-DIVERSITY; HABITAT STRUCTURE; TIDAL COMMUNITY; UPLAND STREAM; NEW-ENGLAND; DISTURBANCE; COLONIZATION }, url = {http://www.jstor.org/stable/2670734}, issn = {0024-3590}, year = {1999}, date = {1999-09-00}, journal = {Limnology and Oceanography}, volume = {44}, number = {6}, pages = {1522-1529}, abstract = {This study explored the mechanisms by which crevices act as refugia for small algae during abrasive disturbances. Four substrates with different crevice features were subjected to three levels of abrasion in a stream-based experiment. Substrates were sand-grain caddisfly cases and three glass rod substrates that mimicked caddisfly cases in size and shape, as well as forming a gradient of larger crevices (i.e., smooth with no crevices, sanded with shallow pits, and scratched with deeper grooves). Substrates were subjected to no, low, or high abrasion levels during 18 d of incubation by pulling substrates through a sand-gravel mixture in floating enclosures that housed the experiment. Diatom density, relative biovolume, location in crevices, detritus accumulation, and filamentous algal density were compared among substrate types and abrasion levels. Across all abrasion levels, diatom and filamentous algal densities were higher on caddisfly cases than on all three glass rod substrates. Although abrasion greatly reduced overall diatom density, diatoms within crevices were largely protected. Crevice size influenced diatom size and composition. The small crevices of sanded rods contained primarily small diatoms of a single species (Achnanthidium minutissimum), whereas the larger crevices of scratched rods and caddisfly cases contained a greater range of diatom size and, consequently, greater species diversity. Detritus accumulated in all crevices, and accumulation increased with level of abrasion. Diatom biovolume decreased and location in crevices increased with the level of abrasion on the less textured smooth and sanded glass rods. Abrasion level had little effect on algal assemblages on caddisfly cases. This study demonstrates that crevices can be important refugia from abrasive disturbances, and that the size of crevices relative to organismal size can influence the protective value of crevices.}, note = {Note that the file size exceeds the maximum allowable for the Angelo database. Please see the attached stable URL for a link to the PDF.}, keywords = {algal communities, colonization, disturbance, habitat structure, marine-invertebrates, New England, rocky intertidal community, species-diversity, tidal community, upland stream}, pubstate = {published}, tppubtype = {article} } This study explored the mechanisms by which crevices act as refugia for small algae during abrasive disturbances. Four substrates with different crevice features were subjected to three levels of abrasion in a stream-based experiment. Substrates were sand-grain caddisfly cases and three glass rod substrates that mimicked caddisfly cases in size and shape, as well as forming a gradient of larger crevices (i.e., smooth with no crevices, sanded with shallow pits, and scratched with deeper grooves). Substrates were subjected to no, low, or high abrasion levels during 18 d of incubation by pulling substrates through a sand-gravel mixture in floating enclosures that housed the experiment. Diatom density, relative biovolume, location in crevices, detritus accumulation, and filamentous algal density were compared among substrate types and abrasion levels. Across all abrasion levels, diatom and filamentous algal densities were higher on caddisfly cases than on all three glass rod substrates. Although abrasion greatly reduced overall diatom density, diatoms within crevices were largely protected. Crevice size influenced diatom size and composition. The small crevices of sanded rods contained primarily small diatoms of a single species (Achnanthidium minutissimum), whereas the larger crevices of scratched rods and caddisfly cases contained a greater range of diatom size and, consequently, greater species diversity. Detritus accumulated in all crevices, and accumulation increased with level of abrasion. Diatom biovolume decreased and location in crevices increased with the level of abrasion on the less textured smooth and sanded glass rods. Abrasion level had little effect on algal assemblages on caddisfly cases. This study demonstrates that crevices can be important refugia from abrasive disturbances, and that the size of crevices relative to organismal size can influence the protective value of crevices. |
1997 |
Kotanen, Peter M Effects of gap area and shape on recolonization by grasslands plants with differing reproductive strategies Journal Article Canadian Journal of Botany, 75 (2), pp. 352 - 361, 1997, ISSN: 0008-4026. Abstract | Links | BibTeX | Tags: disturbance, gap shape, gap size, grasslands, revegetation, succession @article{Kotanen1997, title = {Effects of gap area and shape on recolonization by grasslands plants with differing reproductive strategies}, author = {Peter M. Kotanen}, url = {http://angelo.berkeley.edu/wp-content/uploads/Kotanen_CanadianJournalofBotany1997.pdf}, issn = {0008-4026}, year = {1997}, date = {1997-02-00}, journal = {Canadian Journal of Botany}, volume = {75}, number = {2}, pages = {352 - 361}, abstract = {Species with poor dispersal ability initially should be slower to colonize larger or rounder gaps than smaller or less circular gaps. Conversely, dispersive and seed-banking species should be less sensitive than poor dispersers to gap size and shape, and less confined near the edges of a gap. I tested these ideas with a 3-year experiment in which I monitored the revegetation of gaps in grassland vegetation. Initially, species reproducing largely by clonal growth (bulbs and perennial graminoids) were the most sensitive to gap size and (to a lesser extent) shape, reaching their greatest abundances in small and (or) rectangular openings. Species relying on seed dispersal (annual grasses) also tended to do best in smaller plots, but were less concentrated near the edges of the plots. Species relying on seed dormancy (dicots and Juncus bufonius) were least sensitive to plot size, shape, and distance from an edge. In subsequent years, these patterns often were obscured or reversed, reflecting continuing seed immigration and environmental and competitive conditions within gaps. These results indicate that species respond to gap size and shape in ways consistent with their reproductive biologies, and suggest that the importance of the dimensions of gaps may vary among plant communities.}, keywords = {disturbance, gap shape, gap size, grasslands, revegetation, succession}, pubstate = {published}, tppubtype = {article} } Species with poor dispersal ability initially should be slower to colonize larger or rounder gaps than smaller or less circular gaps. Conversely, dispersive and seed-banking species should be less sensitive than poor dispersers to gap size and shape, and less confined near the edges of a gap. I tested these ideas with a 3-year experiment in which I monitored the revegetation of gaps in grassland vegetation. Initially, species reproducing largely by clonal growth (bulbs and perennial graminoids) were the most sensitive to gap size and (to a lesser extent) shape, reaching their greatest abundances in small and (or) rectangular openings. Species relying on seed dispersal (annual grasses) also tended to do best in smaller plots, but were less concentrated near the edges of the plots. Species relying on seed dormancy (dicots and Juncus bufonius) were least sensitive to plot size, shape, and distance from an edge. In subsequent years, these patterns often were obscured or reversed, reflecting continuing seed immigration and environmental and competitive conditions within gaps. These results indicate that species respond to gap size and shape in ways consistent with their reproductive biologies, and suggest that the importance of the dimensions of gaps may vary among plant communities. |
1996 |
Wootton, Timothy J; Parker, Michael S; Power, Mary E The effect of disturbance on river food webs Journal Article Science, 273 (5281), pp. 1558-1561, 1996. Abstract | Links | BibTeX | Tags: disturbance, food web, model @article{Wootton1996, title = {The effect of disturbance on river food webs}, author = {J. Timothy Wootton and Michael S. Parker and Mary E. Power}, url = {http://angelo.berkeley.edu/wp-content/uploads/Wootton_Science1996.pdf}, doi = {10.1126/science.273.5281.1558}, year = {1996}, date = {1996-09-13}, journal = {Science}, volume = {273}, number = {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 = {disturbance, food web, model}, 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. |
J.T. Wootton, Parker M S; Power, M E The effect of disturbance on river food webs Journal Article Science, 273 (5281), pp. 1558-1560, 1996. Abstract | Links | BibTeX | Tags: disturbance, food webs @article{Wootton1996, title = {The effect of disturbance on river food webs}, author = {J.T. Wootton, M.S. Parker and M.E. Power}, url = {http://angelo.berkeley.edu/wp-content/uploads/Wootton_1996_Science.pdf}, year = {1996}, date = {1996-00-00}, journal = {Science}, volume = {273}, number = {5281}, pages = {1558-1560}, 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 = {disturbance, 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. |