Field experiments on responses of a freshwater, benthic macroinvertebrate community to vertebrate predators
The seasonal importance of vertebrate predators in potentially regulating the abundance and diversity of the benthic macroinvertebrates in the littoral zone of a soft-bottom reservoir that receives thermal effluent from a nuclear production reactor was examined. Thirty-six predator (fish and turtle) exclusion cages (4 m/sup 2/) were placed in shallow water at six locations along a thermal gradient in Par Pond, a 1100-ha cooling reservoir on the Savannah River Plant near Aiken, South Carolina, USA. An additional 36 control plots (4 m/sup 2/) were also set up. Cages were in place during three, 3-mo test periods beginning in September 1977. Estimates of benthic density, taxon richness, and distribution within functional groups (defined by feeding mechanism) were calculated for each test period. Effects of temperature on predator-prey relationships were also determined. Experimental results of this study suggest that vertebrate predation was not the fundamental parameter organizing the benthic macroinvertebrate community in the littoral zone of this reservoir. Neither taxon richness nor density of total macroinvertebrates was conclusively related to predator treatment. Relationships between predator treatment and community response (changes in density and taxon richness) were generally unaffected by either plot locality, temperature fluctuations from thermal effluent, or seasonal changes. When data from caged and control plots were pooled, however, both location and water temperature individually had direct impacts on the benthic community. From these results and other field studies it is hypothesized that individual species of keystone benthic predators do not occur in the littoral zone of freshwater lentic environments with soft bottoms.
- Research Organization:
- Savannah River Ecology Lab., Aiken, SC
- DOE Contract Number:
- AC09-76SR00819
- OSTI ID:
- 6482647
- Journal Information:
- Ecology; (United States), Vol. 62:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
BENTHOS
PREDATOR-PREY INTERACTIONS
TEMPERATURE EFFECTS
THERMAL EFFLUENTS
BIOLOGICAL EFFECTS
AQUATIC ECOSYSTEMS
DISTRIBUTION
ENVIRONMENTAL EFFECTS
FISHES
FOOD CHAINS
PRODUCTION REACTORS
SAVANNAH RIVER PLANT
SEASONAL VARIATIONS
THERMAL STRESSES
TURTLES
WATER RESERVOIRS
ANIMALS
AQUATIC ORGANISMS
ECOSYSTEMS
NATIONAL ORGANIZATIONS
REACTORS
REPTILES
STRESSES
SURFACE WATERS
US AEC
US DOE
US ERDA
US ORGANIZATIONS
VARIATIONS
VERTEBRATES
560204* - Thermal Effects- Invertebrates- (-1987)
560205 - Thermal Effects- Vertebrates- (-1987)
520400 - Environment
Aquatic- Thermal Effluents Monitoring & Transport- (-1989)