Piscivores, Trophic Cascades, and Lake Management
The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature...
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| Format: | Article |
| Language: | English |
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Wiley
2002-01-01
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| Series: | The Scientific World Journal |
| Online Access: | http://dx.doi.org/10.1100/tsw.2002.138 |
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| author | Ray W. Drenner Ray K. David Hambright |
| author_facet | Ray W. Drenner Ray K. David Hambright |
| author_sort | Ray W. Drenner |
| collection | DOAJ |
| description | The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing) that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores) and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high) represent classical 3- and 4-trophic level food webs. |
| format | Article |
| id | doaj-art-698765d6133b41a98a89ebafb0e4d957 |
| institution | Kabale University |
| issn | 1537-744X |
| language | English |
| publishDate | 2002-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | The Scientific World Journal |
| spelling | doaj-art-698765d6133b41a98a89ebafb0e4d9572025-02-03T01:20:50ZengWileyThe Scientific World Journal1537-744X2002-01-01228430710.1100/tsw.2002.138Piscivores, Trophic Cascades, and Lake ManagementRay W. Drenner0Ray K. David Hambright1Department of Biology, TCU Box 298930, Texas Christian University, Fort Worth, TX 76129, USAUniversity of Oklahoma Biological Station, HC-71, Box 205, Kingston, OK 73439, USA, and Israel Oceanographic and Limnological Research, Kinneret Limnological Laboratory, P.O. Box 447, Migdal 14950, IsraelThe concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing) that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores) and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high) represent classical 3- and 4-trophic level food webs.http://dx.doi.org/10.1100/tsw.2002.138 |
| spellingShingle | Ray W. Drenner Ray K. David Hambright Piscivores, Trophic Cascades, and Lake Management The Scientific World Journal |
| title | Piscivores, Trophic Cascades, and Lake Management |
| title_full | Piscivores, Trophic Cascades, and Lake Management |
| title_fullStr | Piscivores, Trophic Cascades, and Lake Management |
| title_full_unstemmed | Piscivores, Trophic Cascades, and Lake Management |
| title_short | Piscivores, Trophic Cascades, and Lake Management |
| title_sort | piscivores trophic cascades and lake management |
| url | http://dx.doi.org/10.1100/tsw.2002.138 |
| work_keys_str_mv | AT raywdrenner piscivorestrophiccascadesandlakemanagement AT raykdavidhambright piscivorestrophiccascadesandlakemanagement |