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Published byStephany Evans Modified over 9 years ago
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Cortlyn Davies Mitchell Parsons Craig Woodruff
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Zooplankton ◦ Regulate algal population and control algal blooms. ◦ Important food source for planktivorous fish (e.g. trout).
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Zooplankton ◦ Regulate algal population and control algal blooms ◦ Important food source for planktivorous fish (e.g. trout) Macrophytes ◦ Stabilize sediment ◦ Refugium for zooplankton ◦ Produce oxygen through photosynthesis. ◦ Alternate stable states
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Wisconsin-style closing plankton net Sampled at 3 locations in the pond Full water column samples ◦ Triplicates at each site http://www.wildco.com/images/C/40.jpg
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Subsample each collection Count individuals in subsample Use counts and volumes to estimate denisty Average triplicates, then site averages to estimate pond-wide community http:// m7.i.pbase.com/o6/55/932755/1/1 36788177.9DMgpcet.Cyclopoida4.JPG http:// upload.wikimedia.org/wikipedia/com mons/4/4e/Daphnia_pulex.png
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Predominantly Cladocerans -> Good for fish Majority of Cladocerans are Ceriodaphnia -> too small for fish Many rotifers -> too small for adult fish Zooplankton density is extremely low ◦ Turnbow Pond: 7 ind/L ◦ Spring Valley: 33 ind/L ◦ Carlson Pond: 1515 ind/L ◦ Dynamite lake (Vanni et al. 1987): 1.4 ind/L (Ceriodaphnia)
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Fish stock too high, depressing zooplankton population Hyperpredation due to artificial feeding No refugium in macrophytes Feeding can maintain fish, but low zooplankton has other consequences
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Reduce fish stock Alter community: Piscivores Reduce artificial feeding Establish macrophytes (suggestions to come)
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Biomanipulation http://terraqua-es.co.uk/wp-content/uploads/2012/05/biomanipulation.jpg
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Ten sites in pond body Three sites in each bay Eckman grab sampler Sift and collect macrophytes Clean and dry Weigh to estimate density 3x Google Earth
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Current State: Macrophytes Little macrophyte cover (<1g/m 2 ) – Good for swimming, bad for ecology More in the shallow bays, but still small amount
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Bank to steep to support macrophyte growth (Duarte and Kalff 1988) Unable to establish because too little light for photosynthesis Clearing of all macrophytes when expanded pond
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More gradual incline on bank Buffer to reduce turbidity – increase light Start around edges of pond Plant emergent macrophytes such as lillies ◦ Same function, more aesthetic Low growing submerged macrophytes
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Buffer zone around lake (~50 feet) Alter fish community ◦ Prevent resuspension via swimming on bottom ◦ Increase zooplankton community In turn reduces algae density Establish macrophytes ◦ Prevent sediment resuspension ◦ Provide refuge for zooplankton ◦ Suggest around 50% coverage for diversity and water quality (NRCS 2006 and Hilt et al. 2006)
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Duarte, C. M., and J. Kalff. 1988. Influence of lake morphometry of the response of submerged macrophytes to sediment fertilization. Canadian Journal of Fisheries and Aquatic Sciences 45: 216-221. Hilt, S., E.M. Gross, M. Hupfer, H. Morcsheid, J. Mählmann, A. Melzer, J. Poltz, S. Sandrock, E. Scharf, S. Schneider, and K. van de Weyer. 2006. Restoration of submerged vegetation in shallow eutrophic lakes – A guidline and state of the art in Germany. Limnologica 36: 155-171. Natural Resource Conservation Service. 2006. Farm pond ecosystems. Fish and Wildlife Habitat Management Leaflet. No. 29. Vanni, M. J. 1987. Effects of nutrients and zooplankton size on the structure of a phytoplankton community. Ecology 68: 624-635.
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