Macrophyte Communities of Owasco Lake

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Macrophyte Communities of Owasco Lake
Bruce Gilman Finger Lakes Community College 4355
Lakeshore Drive Canandaigua, New York 14424
Bin Zhu Finger Lakes Institute 601 South Main
Street Geneva, New York 14456
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Holistic Lake Management

• Environmental issues
• Comprehensive study
• Our team focus research questions
• What macrophyte species are present?
• How productive are the macrophyte communities?
• What influences their productivity?

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Sampling Design

• Shallow lake areas
• northern shoals
• southern shoals
• eastern and western shorelines
• Repetitive sampling in June, July, August
• In situ data
• Substrate collection and analyses

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Methods Lake Sampling

• Submerged ½ m2 quardats
• SCUBA diving or snorkeling
• Collection of aquatic plants in mesh bags
• Sample rinse
• Water depth measurement

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Methods Laboratory Work Sorting by speciesAir
drying in college greenhouse
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Methods Laboratory Work
Standing crop biomass reported in g/m2
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Results

• 18 different macrophyte species
• 16 vascular plants, 1 moss, 1 macro-algae
• 2 species are considered invasive curly leaf
  pondweed and Eurasian milfoil
• Our data represent significant additions to
  historic records for Owasco Lake
• First record for a NYS rare plant, the spotted
  pondweed (Potamogeton pulcher)

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Spotted Pondweed
Potamogeton pulcher
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Water Depths
0.30 to 5.20 meters
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Frequency of Occurrence(based on 93 samples)
Elodea
Eelgrass
Leafy Pondweed
Eurasian Water Milfoil
80.6
72.0
64.5
55.9
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Frequency of Occurrence(based on 93 samples)
Water Stargrass
Curly leaf Pondweed
Coontail
Stonewort
54.8
50.5
47.3
31.2
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Frequency of Occurrence(based on 93 samples)
Flat-stem Pondweed
Slender Naiad
Small Pondweed
Water Buttercup
24.7
15.1
12.9
9.7
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Sample Richness

• June
• July
• August
• east/west

• 2 8 species, mean 5.11
• 2 9 species, mean 5.81
• 1 9 species, mean 5.37
• (3 11 species, mean 6.58)

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Biomass Measured(based on 93 samples)

• Stonewort 40.3
• Elodea 27.1
• Eurasian Water Milfoil 8.7
• Eelgrass 6.1
• Leafy Pondweed 5.7
• Curly leaf Pondweed 2.5
• Water Stargrass 1.8

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Standing Crop Biomass

• June
• July
• August

• 2 1263 g/m2, mean 225 g/m2
• 50 1031 g/m2, mean 389 g/m2
• 4 1143 g/m2, mean 390 g/m2

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Annual Productivity Estimate

• 59 1332 g/m2, mean 625 g/m2
• Amazing amounts!

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Regression Analyses(Productivity and Environment)

• r2 .01
• r2 .09
• r2 .28
• r2 .04
• r2 .04
• r2 .00

• Depth
• Substrate phosphorus
• Substrate organic matter
• Substrate sand
• Substrate silt
• Substrate clay

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Questions?
Answers?