Recent History of Submersed Aquatic Plants in Cayuga Lake 1928 To 2017 Northwest Cayuga Lake 80 (+1 SE) 70 Acentria recorded 60 in lake - 1991 50 40 30 % Milfoil 20 10 0 87 88 89 90 91 92 93 94 95 96 97 98 99 Year Cayuga Lake Watershed Network’s Fall Community Conference November 4, 2017 Bob Johnson Albert Vogel’s Cornell Masters Thesis 1973 “Changes in the Submerged Aquatic Flora at the South End of Cayuga Lake between 1929 and Early aquatic plant history1970 from” Al’s Thesis (40 years) Myriophyllum exalbescens (a native species) ID’ed in his Thesis in 1970 is correct for earlier research before Al, however in 1970 his milfoil was the non- native invasive M. spicatum (Eurasian watermilfoil) Past records concentrated on the area south of line from Wheatons on the West shore, through the pile cluster to Willow Point on the East shore Muenscher 1928, Leister 1929, Eurasian watermilfoil Hewitt 1944 and Vogel 1973 Al Vogel conducted his study in 1970 and contrasted his findings with the researchers from 1928 to 1944 who were studying submerged aquatic plants as a food source for ducks. Vogel’s purpose of his study was to determine the changes over the last 40 years. His hypothesis was that abundant growth occurred over a larger area with fewer species and water milfoil as the dominant plant. That all happened, however the watermilfoil identification was not correct. A lot of confusion in the 1960’s as to ID of milfoils. Al Vogel finished his data collection and went back home to CA in 1971 to write his thesis. However on June 21 and 22, 1972 Tropical Storm Agnes deposited 6.7 inches of rainfall in the Cayuga Basin. Cayuga Lake Owasco Lake Lake water levels on June 25 reached a maximum of 3.6 feet above normal and stayed 3 feet above normal for another two weeks. In 1972 most plant species were buried and were deprived of light required to grow. Eurasian watermilfoil the invasive survived at a very low biomass in the fall of 1972. With little plant competition in 1973 watermilfoil expanded it’s range and density greatly, at both the south and north ends of Cayuga Lake. Tropical Storm Agnes Major Disturbance June 21, 1972 17 g dm m-2 milfoil in August of 1972 to 166 g dm m-2 in 1973 in Southern Basin Even greater biomass in Northern basin 1973 (349 g dm m-2) and 1974 (763 g dm m-2) Milfoil at 850 g m-2 in north end Milfoil dominated entire lake through early 1990s Native plant species declined This was common in the 1970s and 1980s. How has that changed ? Exotic Eurasian Watermilfoil Decline in Cayuga Lake in the 1990s Northwest Cayuga Lake 80 (+1 SE) 70 Acentria recorded 60 in lake - 1991 50 40 30 % Milfoil 20 10 0 87 88 89 90 91 92 93 94 95 96 97 98 99 Year Native Plants returned Vallisneria to the Cayuga Lake Plant Communities Northwest Cayuga Lake 70 (+1 SE) 60 Acentria recorded 50 in lake - 1991 40 30 20 % Vallisneria % 10 0 87 88 89 90 91 92 93 94 95 96 97 98 99 Year Growth Control by Insects Insect herbivores played, and still play, a large role in changing and shaping the submersed aquatic plant community in Cayuga and many other lakes 1989 Aquatic Plant Communities in Southern Cayuga Lake before Moth 1997 Aquatic Plant Communities in Southern Cayuga Lake with Moth Native Plant Species Non-native Plant Species: Some in the lake and others to be on the lookout for It is Difficult to Control Mother Nature One cause of the floating mats of plants, especially in the North end of Cayuga Lake, is the natural death of the plant species early in the summer after flowering when they decay and break loose from their roots Potamogeton crispus Potamogeton pusillus Invasive Species of Special Concern Right Now !! Starry Stonewort (Nitellopsis obtusa) found in 2008 off west shore Aquatic plant species community at the South End last year (Number of Occurrences) and Percentage of Each Species out of All Occurrences in 2017 Potamogeton pusillus Potamogeton crispus Alisma gramineum Other (908) 4.4 (490) 2.4 (42) 0.2 (16) 0.1 Myriophyllum spicatum Ranunculus trichophyllus (3416) 16.6 (19) 0.1 Najas flexilis (1273) 6.2 Potamogeton praelongus (48) 0.2 Myriophyllum spicatum Zannichellia palustris Elodea sp. (300) 1.5 Vallisneria americana Ceratophyllum demersum Stuckenia pectinata Potamogeton zosteriformis (993) 4.8 Chara vulgaris Heteranthera dubia Najas guadalupensis Potamogeton foliosus Najas minor Nitellopsis obtusa Nitellopsis obtusa (3340) 16.2 20,631 Stuckenia pectinata Zannichellia palustris Potamogeton praelongus Najas flexilis Ranunculus trichophyllus Alisma gramineum Potamogeton pusillus Elodea sp. Potamogeton crispus (3917) 19.0 Other Najas minor (481) 2.3 Ceratophyllum demersum Potamogeton foliosus (2791) 13.5 Vallisneria americana (404) 2.0 (589) 2.9 Najas guadalupensis (21) 0.1 Heteranthera dubia (1002) 4.9 Chara vulgaris (460) 2.2 Potamogeton zosteriformis (121) 0.6 Aquatic plant species community at the North End this year (Number of Occurrences) and Percentage of Each Species out of All Occurrences in 2017 Other Alisma gramineum Alisma gramineum Zannichellia palustris Ceratophyllum demersum (98) (4) 0.1% (95) 3.1% (165) 5.4% Ceratophyllum demersum 0.2% Chara vulgaris Chara vulgaris Vallisneria americana (240) 7.8% Elodea sp. Elodea sp. (445) 14.4% Heteranthera dubia (6) 0.2% Lemna minor Heteranthera dubia Myriophyllum spicatum (86) 2.8% Stuckenia pectinata Najas flexilis (319) 10.4% Lemna minor Najas guadalupensis (4) 0.1% Najas marina Najas minor Nitella flexilis Myriophyllum Nitellopsis obtusa spicatum Nymphaea odorata (397) 12.9% Potamogeton crispus Potamogeton gramineus 3,082 Potamogeton praelongus Potamogeton pusillus Najas flexilis Potamogeton zosteriformis (98) 3.2% Stuckenia pectinata Vallisneria americana Najas guadalupensis Zannichellia palustris (53) 1.7% Other Potamogeton zosteriformis Najas marina (210) 6.8% (19) 0.6% Najas minor Potamogeton pusillus (22) 0.7% (334) 10.8% Nitellopsis obtusa Nitella flexilis (278) 9.0% Potamogeton praelongus (5) 0.2% Nymphaea odorata (107) 3.5% Potamogeton gramineus Potamogeton crispus (14) 0.5% (17) 0.6% (157) 5.1% We are 6 years into our plan to eradicate Monoecious Hydrilla from the Cayuga Inlet Bob Johnson Location of all recorded hydrilla in the Cayuga Inlet from time of Identification on Aug 5, 2011 to present Current Hydrilla finds in 2017 at the south end of Cayuga Since 2013 we have been finding individual Hydrilla patches in the SE corner of the Lake Cayuga’s important submersed aquatic plant community continues to change and individual native species have disappeared with new invasive species moving in according to plant survey records of the last 89 years. If we went back to 1886 and W.R. Dudley’s “The Cayuga Flora” he reported Myriophyllum spicatum (Eurasian watermilfoil) common in the inlet of Cayuga Lake. The universal accepted year of invasion into North America of Eurasian watermilfoil is 1940. In closing I am optimistic that Cayuga Lake will continue to have diverse submersed aquatic plant communities even with the very aggressive current invaders. .