216

TECHNICAL REPORTS

BFS Technical Report #4

PANTHER LAKE AQUATIC MACROPHYTE

MANAGEMENT PLAN FACILITATION: 1998 UPDATE ON THE DISTRIBUTIONS OF

NUISANCE PLANTS

WILLARD N. HARMAN MATTHEW F. ALBRIGHT

PAUL H. LORD and DARCY KING

SUNY ONEONTA BIOLOGICAL FIELD STATION

5838 ST HWY 80, Cooperstown, NY 13326

November, 1998

217

INTRODUCTION

The role of aquatic plants in freshwater lakes:

Practically all our northeastern lakes support a diversity of large aquatic plants attached to the bottom (benthic macrophytes) which play an important role in maintaining the potable, recreational and aesthetic characteristics, as well as the ecological functioning, of most waters (Anon., 1990). These plants compete directly with algae in the water column (phytoplankton) for nutrients, thereby maintaining water clarity. They protect shorelines from erosion and stabilize deeper substrates limiting turbidity from silts and clays by physical disturbance. By preventing the resllspension of sediments which have nutrients adsorbed to them, algal growth is limited (Wetzel, 1983).

Macrophytes provide food and cover and/or supplement oxygen supplies for all of the organisms (i.e., fish, mammals, amphibians, reptiles and invertebrates) that make up shallow water (littoral) aquatic communities. They are the basis of aquatic food webs in these areas, providing indispensable links between the sun's energy and animals that eat plants which are, in tum, eaten by predators (Hutchinson, 1975). In these ways, plants regulate the size and character ofgame fish and waterfowl populations as well as impact other biotic resources we cherish.

In our region there are a few introduced plant species (e.g., Eurasian rnilfoil, curly leaved pondweed, water chestnut) that aggressively out-compete our native flora under conditions of excess nutrient loading, destroying biodiversity and causing the loss of some of the abovementioned benefits. The dense beds commonly forn1ed by these plants often reduce the recreational quality of lakes. These introduced exotics are responsible for the great majority of the complaints heard from recreational lake users.

Aquatic plant management in the northeast:

Modem managers recognize the benefits of our native plant communities and therefore, under all but emergency conditions, use techniques to control the aggressive introductions while attempting to restore native plant diversity for its inherent values. Techniques can be divided into two types: 1. Those that improve the environment by minimizing nutrient loading, reducing littoral disturbance and preventing further introductions, and: 2. Those that directly impact plant populations.

Even aggressive exotics can become innocuous if cultural pollution (nutrient loading) is minimized. Whole lake and watershed management techniques to control runoff are expensive, often politically charged and must be seen as long-term investments. Nevertheless, they must be addressed to assure unqualified success over time.

Introductions are most aggressive when native plants or substrates are disturbed. It's

218

harder for exotics to achieve dominance if healthy natives already occupy a lake's bottom. Disturbance of lakeside lands also impact littoral areas to the benefit ofexotics directly by sediment deposition which reduces populations of native plants and indirectly by supplying associated nutrients. All things being equal, the fewer nutrients available for plant growth, the less plants will grow, reducing management problems. However, competitive interactions between planktonic algae and benthic plants may result in complex situations complicating management. Efforts to manage non-native plants must be selective. The more exotic species present, the more extensive, and costly, are the management strategies required. By far, most introductions to inland lakes have been traced to the activities of recreational navigation. Lakes with public access should have some mechanism in place to minimize the chances ofnew introductions.

Strategies directly impacting plant populations are normally categorized as: physical (e.g., harvesting, barriers placed on the bottom or water level manipulation), chemical (use of various herbicides) or biological (utilization of other organisms, usually herbivores). Based on the above discussion, it is asswned that management activities normally are directed at selected target species. It is neither feasible nor desirable to remove all plants from a body of water. If necessary, small areas such as channels and spaces around docks can be treated physically for the convenience of individuals. In even more problematic situations mechanical harvesting on a larger scale may be necessary.

Several problems result from harvesting and other means of physical removal of nuisance plants. Since the majority of exotic species are more competitive in disturbed situations, harvesting enhances growth. Because harvesting is non-selective, native plants competing with the target species are also removed allowing exotics to grow even more vigorously. Herbivores which potentially serve as natural biocontrol agents are removed, compounding the problem. Expenses increase since the more an area is harvested, the more it will need harvesting to assure trouble-free utilization of the site.

The use of herbicides has historically been an important tool in macrophyte control. The greatest concerns with herbicides relate to their toxicity. They are poisons. Many can kill non­target plants as well as animals and can cause health problems to lake users. There are also a host of poorly understood, subtle and indirect effects on the biota, nutrient flow and food web relationships. Herbicides are available today that allow selective targeting of nuisance species. "Sonar" (1-Methyl-3-phenyl-5-[-3(trifluoromethyl)phenyl]-4(1 H)-pyridinone) is an exanlple of a product that is best used to control Eurasian milfoil while permitting most other plants to recolonize, re-establishing a nearly complete native plant community. This, and similar products, must be carefully handled by professional applicators with an understanding of aquatic ecosystems. Also, clearly specified targets should be part of plans developed with the involvement of affected stakeholders. There are still many problems to solve regarding maintenance of appropriate herbicide concentrations over time to attain control without killing non-target species.

Biological control protocols for aquatic plant management are just now being developed. They have great potential for ecologically friendly plant management. There is still more to learn,

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as agents become available for utilization. There are at least three native insect herbivores that can help control Eurasian milfoil in our lakes. Euhrychiopsis lecontei, the milfoil weevil, is present in most northeastern lakes and is being stocked to augment local populations in an attempt to control milfoil (Sheldon, 1997). Acentria ephemerella, the milfoil moth, is being tested for similar use (Johnson, et af., 1998). Cricotopus myriophylli, the milfoil midge, is another organism that occurs naturally in our region (Fagnani and Harman, 1987) and attacks Eurasian milfbil in some situations. These organisms, and others, may have a role in the reduction of milfoil allowing for the re-establishment of the native flora in the northern tier of the United States and Canada. Other organisms, such as East Asian grass carp, Ctenopharyngodon Mella, have been used to good effect in some situations, particulary further south. Permitting issues often preclude there use in New York State.

Introductions of non-native herbivores often requires permits in New York State. It should be recognized that in regulated wetlands, plant management activities of any kind require a permit from the NYS Department ofEnvironmental Conservation and the US Army Corps of Engineers. Plans for introductions to attempt biocontrol should be proceeded by intensive monitoring to ascertain native herbivore damage and population densities prior to management decisions. To date, the evidence is tenuous that native herbivore populations, augmented or introduced, control target species successfully.

Efforts to manage aquatic macrophytes should be part of a coherent plan, no matter how formally documented. Involved groups need to precisely articulate goals and coordinate various activities. Physical control, herbicide use and biocontrol procedures are often incompatible and should not be used concurrently except under professional guidance.

PANTHER LAKE

Panther Lake is located in the Oswego County Towns of Constantia and Amboy, (N 43° 19', W 075° 54'). It has a surface area of 49 hectares (121.5 acres), a mean depth of 5 meters (17 feet) (Petreszyn, 1990), and a maximum depth of8 meters (26 feet) (Panther Lake Assn, undated map). Physical and chemical characteristics of the water as analyzed on 31 July 98 fall within ranges indicated in Hohenstein, et. al., 1997. The lake is tea colored, limiting rooted macrophytes to areas shallower than 4 meters (14 feet).

Scope of work:

The SUNY Oneonta Biological Field Station was contracted through the Oswego County Department ofPlanning to develop: 1. A map ofPanther Lake showing the distributions of aquatic vascular plants. The map was created by a combination of aerial photography, SClJBA and free diver swim-overs and water-level observations documented spatially by GPS technology.

We were also to provide a overview of:

220

2. Panther Lake aquatic plant growth characteristics. 3. Information concerning potential management strategies relevant under existing legislative

restrictions. 4. An indication of state-of-the-art options involving harvesting and other physical control procedures, selective and broad-range chemical and biocontrol techniques.

Methods:

We visited Panther on 6/3/98 in order to locate access areas, determine logistics for future work and to make preliminary observations of the plant species, especially those obvious only during the spring. We arranged for future contacts with Mr. Robert Beck, President of the Lake Association and Mr. John Gratzer of the same organization. We returned to Panther Lake on 7/31/98 to complete the major portion of the field work. At that time, we toured the lake with the above mentioned individuals to develop a historical understanding of the situation and to visit present (and former) problem areas. A map was developed using surface observations, free diver SWinl overs and aerial photography. This map indicates locations of surface macrophytes as well as sampling transects and sites where water quality and SCUBA profundal observations were conducted. All the above are documented spatially with GPS data-points.

The locations of the largest macrophyte beds were docUlllented using an average of readings from three different portable GPS units (Garmin II+). None exceeded] ha in size, enough to warrant docUlllentation of boundaries via GPS technologies I. Details were proofed by correlation with beds visible in aerial photographs taken during fly-overs on the same day (7/31/98). Species composition of macrophytes making up surface beds were determined by free divers through actual collection and estimation of amount the bottom covered (substrate percent cover per meter square) by each kind of plant (species). This information is compared to data collected in 1990 by Petreszyn.

Free divers swam seven transects to characterize the littoral vegetation throughout the lake. This enabled us to develop an understanding of the physical attributes (height, density, shape) of the plant community important to determine its value as cover for invertebrates, forage and game fish and to better understand littoral food web dynamics (ecosystem function) in the lake. Plant species were determined according to Fassett (1960) and Borman, et al (] 997).

Results:

Figure 1 is a map of Panther Lake showing beds ofrnacrophytes attaining the surface (represented by stippling). Sites 2 and 5 indicate the most extensive stands. Major shoreward portions are dominated by floating leaved submergents: water shield (Brasenia schreberi), bullhead lily (Nuphar sp.) and fragrant water lily (Nymphaea odorata). These species typically

Boundaries of beds of aquatic macrophytes vary spatially over time according to the nature of the species involved. Therefore, greater precision is misleading. I

~ /'Ci

E,Wf/S CSS

\0 ~ ~

~

1 .L

'f-:­

\

c 1

I

) /

{ ,~~

Figure 1. Panther Lake showing stands of aquatic macrophytes .eaching ~he surface (stippled areas) in 1998. Site 1 reDresents the deepest are:l of the la.l(e wrere water Guallp:. - . analyses ar1d profundal SCL13A obser.;ations took place. Sites 2-5 illustrate areas where transect.) by free divers took place. Sites A-H represent locations where GPS dat~ were collected releva.,t to mapping activities.

f\.) f\.) --"

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occur in less than 1.5 meters (5 feet) of water. The deeper areas of Sites 2 and 5 were dominated by big-leaved pondweed (Potamogeton amplifolius), covering 50-74% of bottom between 1 and 2 meters (3 to 7 feet) in depth. Waterweed (Elodea canadensis) was a co-dominate, reaching its greatest density (up to 49% cover) between 1 and 3 meters (3 to 10 feet). Eurasian milfoil was present in minimal amounts at all depths, attaining maximum densities of 49% cover at 2 meters as did flat-stemmed pondweed, Potamogeton zosteriformis. Fern pondweed (Potamogeton robbinsii) and wild celery (Vallisneria americana) were present at low densities throughout the littoral zone (up to 4 meters [15 feet]). There were lesser amounts of other species. Location of sites using GPS coordinates are listed in Table 1. Figure 2 is a reproduction of Petreszyn' s 1990 map illustrating "areas of dense vegetation" for comparison.

Seven transects from the shoreline to the greatest depths of the littoral zone at the above mentioned sites, as well as sites 3 and 4, documented similar distributions of macrophytes as indicated by Figure 3. In that illustration the macrophytes are arranged tentatively by community type, recognizing central New York species associations, according to the methods of Vertucci et al (1981). The morphologies of community types, taken from Vertucci et al (1981) are represented in Figures 4-7. It should be noted that these descriptions, which include sub-surface assemblages of plants, are identical with the surface beds characterized above. Column 1 in Table 2 has been derived from Petreszyn's work (1990)2, and compares his 1990 survey with our complete list of plant species in Column 2.

Water quality data was collected at Site 1, the deepest part of the lake. Information collected agreed with CSLAP data from 1993-96 summarized by Hohenstein et. al., 1997. Table 3 is reproduced from that contribution. A SCUBA dive at the site anecdotally verified water column characteristics (transparency, color and plankton densities) and profunda! substrate conditions. The bottom at about 7.5 meters (25 feet) was higWy organic with pieces of fern pondweed dominating masses of decomposing vegetation.

Discussion:

Littoral communities throughout the lake are remarkably similar. We did not observe any monospecific beds. Species having taller growth patterns, such as big-leaved pondweed (P. amplifolius), were in a few cases the only plants reaching the surface, creating the appearance of monospecificity in those areas. Ifwe assume species mapped in 1990 strongly dominated in beds that attained the surface, as implied in Figure 2, and that they are not examples of the above mentioned phenomenon, there has been: 1. A tremendous reduction in vegetation along the north and south shorelines outside of

protected bays, and 2. Wild celery (Vallisneria americana) and Eurasian milfoil (Myriophyllum spicatum) that formerly dominated the submerged rnacrophyte community no longer do so.

2 Isoetes, present on Petreszyn's original list, is omitted. We consider Isoetes as an emergent.

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Table 1. Latitude and longitude of collection sites on Panther Lake as indicated in Figure 1.

Site number Activity Profundal SCUBA observations Water quality measurements

Location N 43° 19.70' W 75° 54.38'

2 Two free diving transects Intensive macrophyte collections

N 43° 19.74' W 75° 54.04'

3 One free diving transect Intensive macrophyte collections

N 43° 19.53' W 75° 54.20'

4 Two free diving transects Intensive macrophyte collections

N 43° 19.68' W 75° 54.66'

5 Two free diving transects Intensive macrophyte collections

N 43° 20.02' W 75° 55.04'

A GPS waypoint (mapping landmark) N 43 19.58' W 7554.05'

B GPS waypoint N 43 19.53' W 7554.20'

C GPS waypoint N 43 19.68'

W7554,87

D GPS waypoint N 43 19.80" W 7554.88'

E GPS waypoint N 4320.04' W 7555.09'

F GPS waypoint N 43 19.81' W 7554.45'

G GPS waypoint N 43 19.72' W 7554.20'

H GPS waypoint N4319.77' W 7553.99'

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Figure 2. Distributions of dominant aquatic macrophytes (shaded areas) in Panther Lake in ] 990 (rt'produccd without modification from Petreszyn, 1990)",

225

Figure 3. Distribution of macrophytes along the depth gradient in Panther Lake, Oswego

County, NY, July_31 1998 (Average of7 transects). __=24% or less cover/m2, 25­

49% coverlm2, _50-74% cover/m2

. Numbers in parentheses indicate communities of Vertucci, cl aI, 1981. Numbers in brackets indicate tentative community a<;signments.

Depth in meters Taxa 1/2 2 3 4

Nup!Jnr sp. (1) Nymphaea odorata ( I ) RalllnlCufliS aqua/ilis (1) lJrasenia sc!I)'eheri [ IJ Chara sp. (4) Najasflexilis (4) Po/amogeton pusil!us (4) Po/umogeton robhinsii [4]

(4) Val!isneril' americana (2) Jle/enmthera dubia (2) Myriophyllum spicatum - [2J Potanwgetoll zos/eriformis ••••• _

Potamoge/oll amplijiJlius ••••

~~_(1)

Po/amoge/of] epihydrus r2J U/ricularia vulgaris [2[ Elodea canadensis (2) Ni/ella hyalina [3 ]*

*Typically occurs in deep water or as an understory in the shade of'other plants.

MacroJlhytr communitirs as distributed along environmental gradients in Otsego Lake (Vertucci, et al 1981)

( 'ol11mllnilv Dept II Urgclllic r-.latl~r Ca(:Ol FXlractalJle Fe Tvpe (Meters) (Sediment) (Sedi ment) (Sediment)

I OS-15m 12-I /I';';IOM (1-9%CaCOJ 1000- J 20()l11g/1 .) 1-2.51lJ J2-14%OM 20-50%CaCOJ 250-1 500mg/l

3-6 5111 12-14%Oi\1 20-50%)('aC03 12S0-1750mg/l I)-fUm ~-12%OM SO-70%Cacnj 0-250mg/1

226

N vanegi./{tlfn N.odo'-iJta

- --- --- -----_.. - ----_.'- -._---- -- --------j

1111

(()MMlJNITYI YI'L I

Figure 4. A diagrammatic view of the vertical structure of community type I (Vertllcci et aI, 1981 ).

I ()r\1~,1I1~~1 [y I \'\'1. II

Figure 5. A diagrammatic view of the vertical structure of community type II (Vertucci el

aI, 19H J ).

227

(

CflMMUNl1 Y nrlill

Figure 6. A diagrammatic view of the vertical structure of commuDity type 1[[ (Vetiucci el

al,1981).

, (H.1.\IIJNII Y 11 Pl:· IV

Figure 7. A diagrammatic "iew of the vertical structure of community t)'PC IV (Vertucci et

ai, 1981).

228

Table 2. Species of submerged aquatic macrophytes present in Panther Lake, Madison Co., NY in 1990 and 1998.

1990 (from Petreszyn, 1990) Nuphar advena (S)I Nymphaea /uberosa (S)

Chara sp. (S)

Potamogeton robbinsii (M) Potamogeton amplifolius (M) Vallisneria americana (M)

Myriophyllum spicatum (M)

Elodea canadensis (S)

Ceratophyllum demersum (S) Potamoge/on praelongus (M)

1998 Nuphar variegatum (1)2 Nymphaea odora/a (1) Ranunculus aquatilis (1) Brasenia schreberi [1]3 Chara sp. (4) Najasjlexilis (4) Potamogeton pusillus (4) Potamogeton robbinsii [4] Potamogeton amplifolius (4) Vallisneria americana (2) Heteranthera dubia (2) Myriophyllum spicatum [2] Potamogeton zosteriformis (2) Potamogeton epihydrus [2] Potamogeton angustifolius [2] Utricularia vulgaris [2] Elodea canadensis (2) Nitella hyalina [3]

1 Abundance (S)=Scarce, (M)=Moderate (See Figure 3 for indications of abundance for 1998 data) 2 Communities of Vertucci, et ai, 1981 3 Tentative assignment to communities of Vertucci, et ai, 1981

---------

--

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Table 3. CSLAP data summary for Panther Lake (from Hohenstein el ai, 19Y7).

.. Avg Max N Parameter

3.14 t.GO 31 CSLAP.Zsd 3.26 4.00 8 CSLAP Zsd 3.26 3.7.5 9 CSLAP Zsd 3.08 3.88 6 CSLAP Zsd 2.93 3.50 8 CSLAP Zsd

Avg Max N Parameter O.OJ 1 0.017 31 CSLAP Tot.P 0.011 0.014 8 CSLAP ToLP 0.010 0.012 9 CSLAP ToLP (l 0 J I OJ) J 7 6 CSLAP TOIP () (I I I () Ii I 1 R ('SLAP laIr '-~--- ._--­

Year Min ._------_.

1993-% 2.38

1996 2.75._------- ­1995 2.50_. 199~ 2.50

1993 2.38

Year Min .. 1993-96 0.007

1996 00091-._-_._.

J995 0.009

] ,!')·1 o (J(I! ---~-_.

1'!')l () (II) 'i ---- .-- .__ .. ._--~---

\. C ;11 i\ 1i I)·__·_·---1--·- . I ')I).J.')!) (iH

I t) '),', ",' .~ --- --_._- ---­

I'!'! :\ :-\(1

I \) ,!.j () l)

I 'J'! 'i ( 1,"1

Year r,f i It

J 1)1) 1·1)() I .-J II J ljL}() I I ~II

I 'jl).:::'" I; ~;

I C),) I 7(,\

I ill) ~ I'"

...

..-- -­

.

2~b... ~~:.t~ __ ~'-__ Par~lIlClrr ---1

77 115 JI CSLAP Cond25 .._._. -- _.-- ----- ._----­

7S R(I S CSLAP Conet2 <; _._----- -_._-_.------ -­._--~

fX2 85 . ()._. __ (SLAP Cond25

j7~. 7-1 . __ 6____ C-~u~P C~(~~ _ , ! I 7, S CSLAP ('01\ d2S

1\1:1, N I'lll-amdcr~\[: .. ------_. ...-----_._----~

(l.l)h . l~ ~HO ... ~ 1.311. ~_. ~~0!:.S II ~l . )II, I I! 7[) ii ('SI.!\1' ('IJi it

J I i~; 1·1 Xi' I; CSL/ll' Chi"-_.. --- --- --_. _.~. ------~

, I·' J U 7CJ S CSL.'\.P ChI it - ---- - -- ._------- -_._ .. _.- .. ­-~- ----~---_

:, ~'7 II II) r: CSLAP ('Iii :1 __ .... J.J ~. ~ .._..~.~~-_~_~-~_

230

Comparing the species lists presented in 1990 by Petreszyn with 1998 data (Table 2) indicates several changes. The water lilies, Nuphar variegatum and Nymphaea odorata are present in Panther today; Petreszyn listed Nuphar advena and Nymphaea tuberosa. We assume the latter represent misidentified taxa. We did not encounter coontail (Ceratophyllum demersum) nor whitestem pondweed (Potamogeton praelongus) recorded by Petreszyn. We did observe four other pondweeds (P. epihydrus, P. pusillus P. angustifolius and P. zoster/ormis) as well as bushy pondweed (Najasflexilis), starflower (H dubia), water shield (Brasenia schreberi), bladderwort (Utricularia vulgaris) and the stonewort (Nitella hyalina). Further comparisons are fraught with difficulties. The terms scarce and moderate, as Petreszyn (1990) used them, are difficult to rectify with plant abundance expressed as percent cover, particularly with diver vs. surface observations.

Temporal changes between 6/3/98 and 7/31/98 indicate seasonal changes in growth between species. Fern pondweed (P. Robbinsii) appeared more abundant in the qualitative samples taken in June than the quantitave work in July indicated. Eurasian milfoil was less obvious in Jtme than in July. Individuals of this species showed evidence of pathology that may indicate current unauthorized herbicide use.

It should be noted that, although present, yellow starflower (H dubia), a problem species in late summer in many lakes, presents no concerns in Panther Lake. Two other plants that often present problems in other lakes, sago pondweed (P. pectinatus) and curley leaved pondweed (P. crispus), were not seen in the lake. The latter, another introduced exotic, commonly causes as many problems as Eurasian milfoil, though much earlier in the growing season.

Management concerns:

Panther Lake has a mix of 18 species of submerged aquatic macrophytes creating a diverse littoral community with successional change during the growing season (phenology) providing constantly changing structure (physiognomy) analogous in many ways to the grotmdcover, tmderstory and canopies typical of forest ecosystems. In our opinion, this mix of species is close to ideal for lakes the size and shape ofPanther Lake. The only aggressive exotic present is Eurasian milfoil, which in the summer of 1998 posed no obvious concerns. The extent of beds of shallow water plant species attaining the surface seem to vary from year to year. These changes are normal and should be expected.

In the short term, if lake users are not satisfied with the current situation, we recommend physical removal, by hand, of problem plants around docks and in swimming areas. The use of tightly woven synthetic fiber barriers may also be effective in these situations. Care should be taken to minimize substrate disturbance. Attempts to bury shallow water plants by introducing sand in beach areas is fruitless and, in the long run, will worsen the situation. Mechanical harvesting is not warranted. Non-specific herbicides are, in our opinions, potentially dangerous to the stability of the condition of the littoral community as it now exists. Specific herbicides generally target Eurasian milfoil, which is not a problem at this time. Ifmilfoil increases in abundance in the future, professionally applied selective herbicides should be considered. At that

231

time the status ofbiocontrol methodologies should be also investigated. Any consideration of biocontrol should be preceded by intensive monitoring of herbivore populations. The only organisms now under consideration are for the control ofEurasian milfoil. Generalized vertebrate herbivores, such as grass carp, would jeopardize the present plant communities' value for food and cover for native organisms and is potentially not permitted by government agencies.

Educational programs and other preventative measures are recommended to assure that stakeholder expectations equal realistic plant management goals. Such programs can help prevent further introductions of noxious plants such as curley leaved and sago pondweeds (P. crispus, P. pectinatus), and should be considered. These same strategies may minimize the chances of introducing exotic zooplankton (e.g., spiny water-fleas [Bythotrephes cederstroemi]), zoobenthos (e. g., zebra mussels [Dreissena polymorpha]) and fish (nekton) (e.g., alewives [Alosa pseudoharengus]), all ofwhich are present in nearby Oneida Lake and could create serious problems. Techniques vary from sinlple signage at launch sites to boat washing facilities and boat registration schemes.

Changes in the distributions of emergent plants along the shores and increasing layers of mud over sandy bottoms are indicative of gradual increases in nutrient enrichment. Long-term planning should involve land use regulations to minimize nutrient (phosphorus) runoff from the watershed from compacted surfaces (roofs, paved roads and driveways, patios, etc.) near the lake, its tributaries, and septic systems. Sewage problems are not documented, but homes with small setbacks from shorelines on sandy soils are indicative ofhigh nutrient loading potential. Plants can't flourish without nutrients.

We stand ready to assist with whatever follow up monitoring, education or other activity the Panther Lake Association or Oswego County Planning Department desire.

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REFERENCES

Anon. 1990. Diet for a small lake: A New Yorker's guide to lake management. NYSDEC and NYS Federation ofLake Associations.

Borman, S., R. Korth and 1. Temte. 1997. Through the looking glass: A field guide to aquatic plants. Wisconsin Lakes Partnership, Merrill, Wisconsin.

Gagnani, 1. P. and W. N. Harman. 1987. The Chironomidae ofOtsego lake with keys to the immature stages of the Subfamilies Tanypodinae and Diamesinae (Diptera)

Fassett, N. C. 1972. A manuel ofaquatic plants. Univ. Wisconsin Press. Madison. 405 pp.

Hohenstein, B.R., G. Gallinger and S. A Kishbaugh. 1997. 1996 interpretive summary: New York citizens statewide lake assessment program (CSLAP), Panther Lake. NYSDEC Div. of Water.

Hutchinson, G. E., 1957. A treatise on limnology, Vol. III. Aquatic macrophytes and attached algae. John Wiley and Sons, Inc. New York.

Johnson, R. L., E. M. Gross and N. G. Hairston, Jr. 1998. Decline of the invasive submersed macrophyte Myriophyllum spicatum (Haloragaceae) associated with herbivory by larvae of Acentria ephemerella (Lepidoptera). Aquatic Ecology 31 :273-282.

Panther Lake Assn. Undated. Bathymetric map of Panther Lake

Petreszyn, 1. M. 1990. Oswego County aquatic vegetation management program, 1990 County­wide assessment. Report No.1: 1-50.

Sheldon, S. P. 1997. Investigations on the potential use of an aquatic weevil to control Eurasian watermilfoil. Journal of Lake and Reservoir Management. 13(1):79-88.

Vertucci, F. A, W. N. Harman and 1. H. Peverly. 1981. The ecology of the aquatic macrophytes ofRat Cove, Otsego Lake, NY. SUNY Oneonta Bio. Fld. Sta., Occas. Pap. 8:1-210. SUNY Oneonta.

Wetzel, R. G. 1983. Limnology. 2nd Ed. Saunders. Philadelphia.