Macrophyte Communities of Owasco Lake
Bin ZhuFinger Lakes Institute601 South Main StreetGeneva, New York 14456
Bruce GilmanFinger Lakes Community College4355 Lakeshore DriveCanandaigua, New York 14424
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?
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
Methods – Lake Sampling
• Submerged ½ m2 quardats
• SCUBA diving or snorkeling
• Collection of aquatic plants in mesh bags
• Sample rinse• Water depth
measurement
Methods – Laboratory Work Sorting by species
Air drying in college greenhouse
Methods – Laboratory Work
Standing crop biomass reported in g/m2
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)
Spotted Pondweed
Potamogeton pulcher
0.30 to 5.20 meters
Water Depths
Frequency of Occurrence(based on 93 samples)
Elodea EelgrassLeafy Pondweed
Eurasian Water Milfoil
80.6% 72.0% 64.5% 55.9%
Frequency of Occurrence(based on 93 samples)
Water StargrassCurly leafPondweed
CoontailStonewort
54.8% 50.5% 47.3% 31.2%
Frequency of Occurrence(based on 93 samples)
Flat-stemPondweed
Slender Naiad Small PondweedWater Buttercup
24.7% 15.1% 12.9% 9.7%
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)
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%
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
Annual Productivity Estimate
59 – 1332 g/m2, mean = 625 g/m2
Amazing amounts!
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
Questions?Answers?