1993

1994

1995

1996

1997

1998

1999

2000

2001

number of sites sampled

75

102

104

104

104

104

104

104

104

all submersed vegetation

13.3

27.5

12.5

20.2

66.3

31.7

72.1

52.9

25.0

coontail

4.0

1.0

-

-

1.9

-

1.9

1.0

4.8

Canadian waterweed

Elodea canadensis

-

-

-

-

6.7

4.8

14.4

5.8

1.9

water stargrass

Heteranthera dubia

-

-

1.0

-

1.0

27.9

66.3

49.0

18.3

Eurasian watermilfoil

Myriophyllum spicatum

1.3

1.0

-

-

1.0

1.0

2.9

1.0

-

curly pondweed

Potamogeton crispus

-

7.8

-

3.8

20.2

-

1.0

-

1.0

leafy/small pondweed

P. foliosus/P. pusillus

-

-

-

-

2.9

-

-

-

-

longleaf pondweed

P. nodosus

-

-

-

-

1.0

-

-

-

-

sago pondweed

P. pectinatus

9.3

19.6

11.5

17.3

50.0

1.9

2.9

1.0

3.8

wild celery

Vallisneria americana

-

-

-

2.9

1.9

3.8

14.4

10.6

1.9

horned pondweed

Zannichellia palustris

-

-

-

-

-

-

-

1.0

-

all rooted floating leaf vegetation

24.0

21.6

20.2

19.2

36.5

35.6

45.2

41.3

67.3

American lotus

Nelumbo lutea

16.0

10.8

19.2

19.2

36.5

35.6

45.2

41.3

65.4

white water-lily

Nymphaea odorata

12.0

11.8

1.9

-

-

-

1.0

-

3.8

Total number of species recorded

5

6

4

4

10

6

9

8

8