aquatic plants of the three lakes · 2016. 6. 24. · aquatic plants of the three lakes chris...

Aquatic Plants of the Three LakesChris Doyle, CLMSenior Aquatic Biologist/Water Quality Program Supervisor

Allied Biological, Inc.580 Rockport Road Hackettstown, NJ 07840Phone: 908-850-0303E-mail: doyle@alliedbiological.com

Rake Toss Methods

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• Based on Point Intercept Methods • Developed by Cornell University

• Standard Weed Anchor Used• Two 13” wide metal rakes attached back to back• 10 meter rope

• Two Rake Tosses per Site • Sites GPS-referenced

•Midtech RX 400p GPS Receiver•Smartpad II (Ver. 4.02) Data Logger

• Standard Plant Densities Used• Submersed and floating plant densities separated• All plants identified to species (if possible)• All plants digitally photographed• Voucher specimens collected to verify field identification

Survey Conducted August 6 & 7, 2008 (~17 hours on the water)

Factors Affecting the 2008 Survey

Littoral Zone

Usually defined as >15 feet

Limited at the Three Lakes

Restricted to shoreline zones, East and West ends of lakes, and shallow coves

Rocks

Restricted the retrieval of the weed anchors

Two anchor tosses per site

Methodology tends to result in increased occurrence, but a decrease in overall density

Hand Pulling

Alters aquatic plant assemblage

Canal Sampling

One anchor toss per site

Aquatic Macrophyte Scientific Name Lake Waccabuc

Lake Oscaleta

Lake Rippowam

Arrowhead (rosette) Sagittaria sp. X XBass Weed Potamogeton amplifolius X XBenthic filamentous Algae X X XBrazilian Elodea Egeria densa XBrittle Naiad Najas minor XCommon Waterweed Elodea canadensis X XCoontail Ceratophyllum demersum X XCreeping Bladderwort Utricularia gibba X XCurly-leaf Pondweed Potamogeton crispus XDwarf Water Milfoil Myriophyllum tenellum XEurasian Water Milfoil Myriophyllum spicatum X X XFlat-stem Pondweed Potamogeton zosteriformis XFloating Filamentous Algae X XLeafy Pondweed Potamogeton foliosus X XRibbon-leaf Pondweed Potamogeton epihydrus XRobbins Pondweed Potamogeton robbinsii X XSpatterdock Nuphar variegata X X XSpiral-fruited Pondweed Potamogeton spirillus XStonewort Nitella sp. XWater Stargrass Zosterella dubia XWatershield Brasenia schreberi X XWater-thread Pondweed Potamogeton diversifolius XWhite Water Lily Nymphaea odorata X X X

The Aquatic Plants of the Three Lakes

Eurasian water milfoil• Myriophyllum spicatum• Aggressive, exotic•Most common aquatic plant found during 2008 survey• Tolerates a wide range of substrate types• Creates canopies at surface to shade out other plants• Monoculture stands reduce aquatic biota diversity• Reproduces via fragmentation (but seeds and roots, too)

Pondweeds

Bass Weed (Potamogeton amplifolius)

Robbins Pondweed (Potamogeton robbinsii)

• Diverse group of aquatic plants• Most are desirable natives• Create excellent fish habitat, cover, and food sources• Most are prolific seed producers• Robbins Pondweed creates dense bottom cover

Pondweeds (con’t)• Leafy Pondweed (P. foliosus)

• Fine leaves, low growing• Often crowded out by invasives

• Ribbon-leaf Pondweed (P. epihydrus)• Produces floating leaves

• Flat-stem Pondweed (P. zosteriformis)• Easily confused with water stargrass Leafy Pondweed (P. foliosus)

Flat-stemPondweed (P. zosteriformis)Ribbon-leaf Pondweed (P. epihydrus)

Pondweeds (con’t)Curly-leaf Pondweed (P. crispus)• Aggressive, exotic plant• Native to Europe• Early season grower

• Naturally dies back in June-July• Produces pine cone-like turions• Can overwinter under the ice• Very common throughout New York

Waterweeds• Brazilian Elodea (Egeria densa)• Aggressive, Exotic• Discovered in Lake Waccabuc

• Isolated in cove• First documented infestation in Westchester county• Likely the result of an aquarium dump (2-3 years ago?)• 2009 Eradication Program

• 4 to 6 leaves in whorl• Common Waterweed (Elodea canadensis)• Desirable native, very common• Questionable identification?• 3 leaves in whorl

Coontail• Ceratophyllum demersum• Very common submersed plant in NY• Lacks a true root system

• Can move around basin• Can also be loosely anchored via modified leaves

• Desirable native species• But can reach nuisance densities

• “Coontail Pods” used by pond managers as a nutrient sink• Leaves arranged in a whorl (5-12)

•Typically stiff and calcified

Arrowhead• Actually an emergent plant, found along the shoreline• Submersed rosettes recovered during survey• Difficult to determine species from rosette• Excellent wildlife habitat and food source• Stabilizes the shoreline and acts as a nutrient buffer

Dwarf water milfoil• Myriophyllum tenellum• Related to Eurasian water milfoil• Uncommon in NY

• But often overlooked• Slender, unbranched stems

• 2-15 cm tall• Leaves reduced to scales

• Excellent sediment stabilizer• Often creates a dense carpet on bottom• Prefers shallow water with sandy substrate

Stonewort

Creeping Bladderwort

• Nitella sp.• Actually, a multi-branched algae• Shares the ecological niche of other macrophytes

• Utricularia gibba• Only bladderwort collected in 2008• Lacks true roots• Bladders used to capture prey

•Protozoa, insect larvae

Water Lilies• Leaves float on the surface• Provide shade and cover• Can reach nuisance density• Reproduce via rhizomes

Three species observed at the Three Lakes during 2008 survey• White Water Lily (Nymphaea odorata)

• Round leaves with prominent notch; white flower• Watershield (Brasenia schreberi)

• Underside and stem covered with gelatinous mucus; tiny purple flower• Spatterdock (Nuphar variegata)

• Large oval leaves; also called yellow lily

Additional Aquatic Plants

Aquatic Macrophyte Total Abundance Trace Abundance Sparse Abundance Medium Abundance Dense Abundance

Sites % Sites % Sites % Sites % Sites %Total Sites 114Total Submersed Vegetation 95 83% 24 25% 53 56% 14 15% 4 4%Eurasian water milfoil 91 80% 36 40% 47 52% 8 9%Benthic Filamentous algae 36 32% 23 64% 11 31% 2 6%Bass weed 34 30% 22 65% 8 24% 4 12%Coontail 21 18% 8 38% 9 43% 3 14% 1 5%Robbins Pondweed 14 12% 13 93% 1 7%Creeping Bladderwort 8 7% 7 88% 1 13%Flat-stem Pondweed 4 4% 4 100%Arrowhead Rosette 4 4% 4 100%Common Waterweed 3 3% 2 67% 1 33%Leafy Pondweed 2 2% 2 100%Dwarf Watermilfoil 2 2% 2 100%Curly-leaf Pondweed 1 1% 1 100%Spiral-fruited Pondweed 1 1% 1 100%Brazilian Elodea 1 1% 1 100%Total Floating Vegetation 62 54% 23 37% 18 29% 17 27% 4 6%Watershield 40 35% 20 50% 11 28% 9 23%White Water Lily 31 27% 19 61% 6 19% 5 16% 1 3%Floating Filamentous Algae 19 17% 10 53% 6 32% 3 16%Spatterdock 16 14% 9 56% 6 38% 1 6%

Lake Waccabuc 2008 Aquatic Plant Distribution

Questions?