I1:\DARRIN 'SrI Fresh Water Institute Lake George, New York Adirondack Field Station at Bolton Landing
A SURVEY OF TRIBUTARTRS IN THE NORTH BASIN OF LAKE GEORGE, NEW YORK FOR TH F: PRESENCE OF EURASIAN W ATERMILFOIL
prepared for The Fund for Lake George
by
Lawrence W. Eichler Research Scientist
&
Charles W. Boylen Associatt: Director
Darrin Fresh Water Institute Rensselaer Polytechnic Institute Troy, NY 12180-3590 Bolton Landing, NY 12g14
DFWT Technical Repolt 1U03-4 TABLE OF CONTENTS
The Survey of T,ake George Tributaries for Eurasian watcrmilfoil- 2002
ExecLllive Summary III
Inlroduction 1
Methods
Results and Discussion 3
References 12
Acknowledgements 12
Appendix A. Site Locations
Appendix B. Macrophyte Community Assessment data
11 Executive summary
A survey of the tributary deltas in the northern portion oftbe Lake George basin was conducted in 2002 to assess the extent o[Eurasian watermilfoil (Myriophyllum spicatum L.) infestation. The project was conducted by the Darrin Fresh Water Institute with Gnaneial support from the Fund for T.ake George. Similar surveys of the northern basin were completed in 1988, 1990, 1993, 1996 and 1999 as reference points. Stream delta areas \vere chosen as n:adily identifiable points which historically harbor diverse assemblages of native aquatic plants. Results of these surveys can he used to approximate the rate of spread of Eurasian watermilfuilthruugh the Lake George basin.
Tn 1988, when tributary surveys were initiated, 22 percent of the sites in the northern third of the Lake Creorge hasin were found to have Eurasian watermilfoil. By 1990, this percentage had increased to 39 percent with a gain 01'7 new Eurasian waternlilfoil sites. By 1993, the percentage oftributmy sites Witll active Eurasian watennilfoil populations had declined slightly to 37%. The decrease was due to hand harvesting of five sites in this ponion of the lake basin. Discovery of four new Eurasian watermil foil sites during the 1993 survey, however, reduced the overall impact of management activities to a net loss of one active Eurasian watermilfoil site. In 1996, a total of 17 sites (42%) had Eurasian watennilfoil, with 2 sites (5%) producing milfoil for the first time. Of the two new Eurasian watennilfoil sites, hoth were restricted to a few plants which were removed. The 1999 survey of the north basin identified 3 new sites (7%) with milfoil present for the first time in the history o[the tributary surveys. A total of I g sites (44%) had milfoil present at the lime of the survey in 1999. All three of the new sites were clearcd of milfoil via hand harvesting. In 2002, no He\v Eurasian watcnnilfoillocations were recorded by the Tributary Survey, however 17 sites (42%) surveyed still supported EuraSIan watennilfoil. fourteen of the 27 sites tllat were positi ve [or mil foil by 1999 had heen clearcd by hand-harvesting or other methods prior to 2002, and have been positive on at least one occasion since the initial hanresting. Thus not only initial colonization but also re-colonization of tributary sites by Eurasian watennilfoil is occuning in Lake George. The rate of colonization, howcver, is variable from year to year and hetween the three portions of the survey.
Smce 1990, the number of tributary sites in tIm portion of the Lake George basin with Eurasian watertlHlfoil present has remained fairly constant. This is largely due to management effol1s supported by the US EPA Clean Lakes Program, the Lake George Park Commission, and the Fund for Lake George. Eurasian watermilfoil continlles to sprcad through the Lake George hasin with an increase in known Eurasian watennilfoil locations of between six and fifteen per year. MaJlagement cflorts to date have been implemented at 132 urthe 144 known Eurasian \vatennilfoilloeations. These management eff0l1s have reduced the Eurasian watennilfoIi biomass at these localions. However, Eurasian watcrrnilfoil has only been eliminated at a handful of sites and reintroduction at thesc locations is likely. At this time, EurasiaJl watermilfoil is ranked 10th by relative abundance (a runetion of mean percent cover), and 29th by frcquency of occurrence for the 39 species found ill the current survey. The fact that Eurasian
iii watennilfoil has reached this level of abundance is a testament to the rapid spread and highly competitive nature of this species.
There is no evidence that loss of Eurasian watennilfoil populations at specific sites in Lake George can he attributed to natural mortality. ThLls maintenance becomes critical following initial management. Maintenance will require site visits yearly or every other year to harvest regrowth. A program to continue maintenance activities iollowing the conclusion of Federal funding in 1993 was deemed imperative. Since 1995, Eurasian watem111foil management in Lake George has been conducted under the auspices of the Lake George Park Commission. Physical controls including hand harvesting, suction harvesting and benthic barrier have been employed since 1995. This program will continue through 2003, with current efforts contracted to Lycott Environmental Services, Inc. A pilot program for herbicide testing was dealt a sethack in 2002 by its failure to acquire a permit from the Adirondack Park Agency. Negotiations continue to acquire the necessary pennits for future herbicide testing. financial support for this program should be sought at local, region8l and fcdcrallevels. Local support exists through the FUND for Lake George, however fincmcial support at th0 state and federal level is also necessary. Introduction
Streams entering Lake George, with nutrients and sedimcnts dcrived from the terrestrial porlion of the basin and deposited on their delta.. , are prime locations for the continued establishment of Eurasian waterrnilfoil (Myriophyllum spicatum L.). Delta areas are also disturbed habi1 Around the entire lakeshore, there are 128 listed stream tributaries (Madsen et aL 1(89). "Recausc human activity in the Lake George basin has historically exacerbated water conditions. relative to disturbed areas, the rate of establishment and spread of milioil has been of particular concern in the management of Eurasian watennilfoil. A survey of all the tributaries in the basin was perfornled as part of the 1987~88 Lake George Aquatic Plant Survey (Madsen el al. 1989). The survey provided a procedure for finding new sites with Eurasian watermilfoil, including the establishment of a regular search pattern for milfoi[ sites to ascertnin the relative distribution of milfoilllillong the native plant communities in Lake George. In order to balance the number of tributary sites surveyed in each year and to stabilize the cost of the survey, the south basin tribularies were divided into two groups in 1991. With approximately 45 tributaries in each group, a three~year cycle of surveys has been established with a south, central and north component of nearly equal number of tributaries. The tributaries of the north basin were the subject of the 2002 survey. The north basin tributary SllTvey was conducted in 1988, 1990, 1991, [996, [999 and 2002 in order to provide information on the rate or colonization of Eurasian waternlilfoil. Since these are readily located sites for whieh the presence or absence of Eurasian watermilfoil was known. these sites were revisited in 2002 to detennine whether appreciable new infestation, re-invasion or natural mortality of earlier infestation had occurred. Methods The shoreline adjacent to tributary outflows in the north basin was surveyed for the presence of Eurasian watermilfoil. The tributaries comprising this portion of the survey were visited betwecn July 30th and October 9th. 2002. Surveys consisted of swimming a I 00~111eter segment of shoreline from the water's edge to the outer edge of the littoral zone. Diver swimover transects were also completed at each si.te in order to characterize the macrophyte community present. Divers skilled in plant identification estimated the abundance or all w..[uatic planl species in each 1 meter (3 fl) depth interval using the following abundance classes: Class Code % Cover Range Centroid Abundant A greater than 50% cover 75.0% Common C 25% to 50% cover 37.5% Pn:senl P 15% to 25% cover 20.0% Occasional 0 5% to 15% cover 10.0% Rare R less than 5% cover 2.5% Percent cover data provides both the average depth distribution of the plants present and an estimate of the relative abumlam.:e of specics at thc tributary sites. This infonnation is also important for future management decisions concerning 111ilfoi1 control alternatives and permil applications required as part of any control strategy. A map showing the general location of this year's survey activity is shown in Figure 1. Specific tributary locations in the current survey an: provided in Appendix A. Figure t. Map of Lake Gcorge indicating the region included in the 2002 Tributary Survey. N 2 Results and Discussion The current survey included the l1orthemmost portion of the lake basin tributaries (41 sites). The southern and central portions of the lake basin were completed in 2000 and 2001, respectively. Maps with the 10l:alions of the tributaries surveyed in 2002 are provided a" Appendix A. The 41 sites surveyed in the 1988, 1990. 1993, 1996 and 1999 programs were replicated in the 2002 survey. Methodologies employed by the three surveys were the same. The resulls of the north basin tributal)' survey for all survey yenrs nre presented in Table 1. For each site, the tributary nwnber and site name is given. Table 1. Tributary survey sites and the presence (Y) or absence (N) of Eurasian watermilfoil. Tribulary if SITE NAME UAI1! 20{)2 1999 1996 1993 1990 1988 T-l OPPOSITE ROGERS RK 3-Sep-02 N N N N N N T-IA MOSSY POINT 3-Sep-02 Y Y Y Y Y Y T-2 C,I.ENRURNIF. 9-0ct-02 N N N N N N T-3 GULL BAY 9-0ct-02 Y Y Y Y Y Y T-3A SMITH BAY 9-0ct-02 N Y Y Y Y Y T-4 SO AI JRNT POINT 9-0ct-02 N N N N N Y T-5 CLARK HOI.! .OW RK 9-0ct-02 Y Y Y N Y Y T-6 SHANTY RAY CREF.K 6-Sep-U2 N Y Y N N N T-7 BROOK N. GREEN PT 6-Sep-01 Y Y Y Y N N T-8 BLUFF HEAD CREEK 7-Aug-02 Y N Y Y Y N T-9 BROOK BY AGNES ISI.AND 7-Aug-02 Y Y Y Y Y N T-IO SUNSETBAYTRIR 7-Aug-02 Y Y Y Y Y Y T-IOA ROCK DUNDER lSI. BROOK 7-Aug-02 Y Y Y Y Y N "1"-11 COOK SAY. HI JJ .ETTS r .NDG 30-Jul-02 N N N N Y Y T-IIS KITCHAL BAY, HULETTS I.NDG 30-.Iul-02 N N N N Y N T-IIN EIClILERVILLE BAY, HtJl.F.TTS )O·Jul-01 Y Y Y Y Y Y T-71 SO TRIB WEST HALFWAY lSI. S-Aug-02 N Y N N Y N T-72 NO TRIB WEST HALFWAY lSI. S-Aug-02 N N N N N N T-72A SO TRIB 5 MI MT BROOK S-Aug-02 Y Y N Y N N T-728 MID TRIB 5MI MT RROOK S.AI![,;-O:? N N N N N N T-73 NO TRIB 5MI MT BROOK 6-Scp-02 Y Y N N N N T-74 SO STEERE lSL BROOK 6-Scp-02 N N N N N N T-75 NO STEERE ISL BROOK 30-.Jul-02 N Y N N N N T-76 SO 9N REST AREA 6-Scp-02 N N N N N N T-78 SABBATH DAY PT BROOK 6-Scp-07 N N N N N N T-79 NORTH SABBATH DAY PT .'i-Scp-02 N N N N N N T-80 NORTH BASS BA Y .'i-Scp-02 N N N N N N T-81 SILVER BAY .'i-Scp-02 N N N N N N T-82 VAN BUREN BAY BROOK .'i-Scp-02 N N N N N N T-82A STARK PT WETLAND 4-Scp-02 N N N N N N T-83 SOUTH JENKINS PT 9-0cl-02 N N N N N N 3 T rihutary f.1- SITE NAME DATE 2002 1999 1996 1993 \9QO 1988 T-84 ('APE (,OD VILLAGE BROOK 9-0ct-02 N N Y N N N T-RS HOLMAN HILL CREEK 4-Sep-02 Y Y Y Y N N T-R6 HAGUE BROOK 4-Sep-02 Y Y Y Y Y N T-S7 TEMPLE ISL BROOK 4-Sep-02 Y N Y Y N N T-SR S TRIB COOKS SAY 3-Sep-02 N N N N N N T-89 SO COOKS BAY 3-Sep-02 Y Y N Y Y N T-90 N TRIB COOKS BAY 3-Sep-02 N N Y N Y Y T-91 SO CAMP SAGAMORE 4-Sep-02 Y Y N N N N T-QIA BROOK IN DARK BAY 4-Sep-02 Y N Y Y Y N T-IOI NORTH OF HAGUE BROOK 5-Sep-02 N N N N N N The results of the six surveys are further summarized in Figure 2. In the 1988 survey, a total of 9 (22%) of the 41 sites had Eurasian walerrnilfoil. In 1990 the total increased to 16 (39%) of the 41 sites surveyed having Eurasian watcrmilfoiL Eight new milfoil sites were found during: the 1990 survey. In the 1993 survey, 15 (37%) of the sites had Eurasian watermilfoil (Table 2). In the 1996 survey, 17 (42%) of the sites had Eurasian watermilfoil, and by 1999 lhis number had increased to 18 (44%). i\ slight decline to 17 sites (42%) wa~ observed in 2002. No new milfoil sites were found in the tributary survey of 2002. Four (10%) of the sites at which milfoil occurred were positive Jor the invasive species since the initial survey in 1988. Eight sites (20%) had mil10il present in previous surveys, but not in the 2002 survey. Fourteen of the 23 siles that were positive for mitfoil by 1996 had heen cleared by hand-harvesting or other methods prior to 2002, and have been positive on at least one occasion since the initial eradication. Thus not only initial colonization but also re~colonjzation or lributary sites by Eurasian watennilfoil is occurring in Lake George. Ibe rate of colonization, howcver, is variable from year to year and bel ween the three portions of the SUf'iCy. }'igure 2. Tributary sites with milfoil in the North Rasin of Lake George, NY Tributary Siles with Milfoil in the North Basin of Lake George, NY 30 --+- New Sites 25 1------Total Sites , _------. ~"' ! -+- Current Sites i .----- 20 I ' ______-~- ~ '"0 ---.------& ------.. ~ 15 .<> E" 10 Z " 5 0 1988 1990 1993 1996 1999 2002 Survey Year 4 By 2002, nine sites (22%) were free of milfoil aller having the plant present in one or more of the prior surveys. Eight sites (20%) were free or Eurasian watcrmilfoil in 1999, although different sites were positive lor milroil. Three sites (7%) had Eurasian watermilfoil in 1988 and 1990 but nol in 1993, and five sites had milfoil in 1990 but not in 199:1. All milfoil was removed by hand harvesting in the years following or during the surveys. Figure 3. Effectiveness of Hand Harvesting on Eurasian Watennilfoil over a long-term period. Hand Harvesting Effectiveness 1000 , -Benlhir !! _ l'inkle Brook Barrier 800 i ---.- Basin Bay Install~d _ Clark Hollo,,"' 600 400 200 o Three sites were selected to demonstrate the eflect hand harvesting can have for management of small populations of Eurasian watennilloil (Figure 3). The tributary survey sites at Finkle Brook (M-15, T-I02), Basin Bay (M-25, '1'-52), and Clark Hollow Brook (M-50, T-5) have all been managcd for the presence of milfoil since the initial surveys were done in 1987 and 1988. The tributary site at the Finkle Arook delta has historically supported Eura.':iian watcnuilfoil populations. Limited numhers of the invasive plant have been fOlmd annually over the past decade. Extensive populations of M spicatum in nearby Sawmill Bay provide a continuing source of milfoil propagu\es to this area. Basin Bay demonstrates the effectiveness of repeated visits of hand harvesting, wherc the local miltoil population appeared to increase in 1993, and it may have gaincd a stronger foothold during 1994, when no management occurred anywhere in the lake. By 1996 it had become a moderate sized popUlation, scattered over a large area. Repetitive hand harvesting of the milfoil in this area has seriously reduced the population. The Clark Hollow site was reported free (or nearly so) of milfoil from 1991 through 1995. The discovery of a small bed in 1998 adjacent to the area normally surveyed resulted in more intensive harvesting. In 200 I, an area of dense growth wa" found adjacent to the hand harvesting location and in 2001 and 2002, benthic harrier was installed at this site as a management activity. In the 1990 survey, the actual number of plants removed was nol recordeJ, but notations indicate a large number of plants too numerous to COllnt were removed from each site. These results indicate that hand harvesting activities can minimize or even eliminate small populations of 5 Eurasian watemlilfoil. There is no evidence. however, that the loss of Eurasian watermilfoil populations at specific sites in Lake George can be aUributed La natural mortality. The 1ollowing is a breakdown of the seventeen sites that had milfoil during the 2002 tributary survey. Eleven of the seventeen milfoi! sites were found to have limited numbers of milfoil plants, all of which were hand harvested to clear the site. No new mil10il sites were found in 2002 hy the current survey. Two locations were added to the list of reported milfoil sites by other programs (King, 2002). The remaining six sites that had milfoil during the 1999 survey all had milfoil populations in one or more of the earlier tributary surveys. Since 1988. the number of tributary sites in this portion of the Lake George basin with milfoil present at least once during the surveys has increased by eighteen. The small number of plants fmUld at most tributary sites indicates recent colonization or reintroduction at these locations. Five of the siles surveyed in 2002 have had a mil foil population since the first tributary survey done in 1988. Those sites being Mossy Point (M-l3), Gull Ray (M-4R). Smith Bay (M-47). Sunset Bay Tributary (M-6), and Eichlervil1e Bay (M-51). All of these sites have been subjects of management activities over the past decade. The sites at Gull Bay, Smith Bay, and Eichlerville were suction harvested, while Mossy Point and Sunset Bay were covered with benthic barrier in 1990 and 1993. respectively. Hand harvesting was conducted at all of the above sites at least once since they were discovered. Hand harvesting of low density milfoil infestations and the use of suction harvesting and benthic harrier on denser growth have been used as a means for maintaining milfoil at low density levels. Of the 17 tributary sites in this section of lhe north basin with milfoil prcsent, hand harvesting and voucher specimen collection cleared 11 sites. Hand harvesting was not completed at the Clark Hollow Brook site (T-5, M-50), Mossy Point (T-IA, M-\3), Eichlerville Brook (T-1IN, M-51), Hague Brook (T -86. M-71), and Gull Ray (T -1, M-48) due to extensive growth of milfoil. A major portion of the site at Sunset Ray (T-I0, M-6) was covered by benthic barrier in 1992-3, but a considerable area remains to be managed. Benthic barrier was installed at Clark Hollow in 2002, and the area of dense growth ofmil1oil significantly reduced. 6 Table 2. Frequen(;y of ocnrrrence of all macrophyte species at the tributary sites (n=41). Species are ranked in order of frequen(;y of occurrence; total is the number of sites at which the species was found. DEPTH IN METERS Spt:cit:s 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Total Pol. Percent cover data for all sites are provided in Appendix B. Ufthe 50 species of submersl:d aquatic plants identified for r ,ake George (Ogden et aI, 1976; Madsen et aI, 19~N), 39 species 7 were found at the tributary sites in 2002. Four of these species are on the New York State Rare Plant List or Watch List (Young, 1993; Young, 2002).lwetes lacustris, Subularia aquatica, Myriophyllum alternfflorum, and MeJ!,u/uc/unlu beckii. This is particularly important for plant management considerations given the impact that a given management tec1mique may have on non-target species. The impact of the growth and spread of nuisance aquatic plants on the distribution of rare plants, however, must also be included in any management decisions. The diversity of species present at tributary sites is indicative of the suitability of these sites lor aquatic plant growth and conversely, thc high probability ofmil1oil inlestation at these sites. Figure 4. Frequency illld depth distribution of the 10 most common macrophyte species and Eurasian watermilfoil. "C " 40 , ~ , "~ , 35 , " I " , 0" 30 I ~ 0 I, ,., 25 I I "C , ChalalNitl'ila 20 I i'u Id{flU get()11 perfi! Ila/us "C" I Mynophyllum leneilum 15 \ Isuetes eclllllos{XJfd I!! , u.. Viillis neTlii iimerwana ! 10 , PotallIogetol) gramme!!> PntamnfJ'I()f) mlhmll 0 [(10 caulon s cptangJlare Lid/ille rnllllmil • Myriophyllum MynophyllllllI SpICatum spicatum Depth (m) 5-6 6-7 In Table 2, the specics prcscnt and thcir dcpth distribution arc rankcd in order of the frequency with which they appeared at the tributary sites. The frequency of occurrence is givcn for each depth interval in which the species was found among all 4 I of the sites surveyed, illld then the total number of sites where the plant was found is given in the "total" column. The depth distributiun or the ten mostlrequently occurring species is presented in Figure 4. Eura<;ian watcrmilfoil, ranked 29th by frcqucncy of occurrence, is also induded in the plot Depth distribution and species diversity remains eomparablc to that reported in previous survcys conducted in the north basin of I.ake George (Madsen et nl, 1989; Eichler et aI, 1994; Eichler et aI, 1997). 8 Tahle 3. Mean percent cover of all macrophyte species at the tributary sites. Species are listed in order of decreasing abundance. Depth Interval Species 0-1 1-2 2-3 3-4 4-5 5-6 (,-7 Totals l'olamogetorl rohhin.~ii 0.1 1.4 5.7 7.3 7.3 6.3 3.0 31.1 Vallisneria americana 4.1 6.7 7.3 5.4 2.8 1.0 0.1 27.4 ( 'haraiNitelia 2.8 2,9 3.4 3.0 3.5 4.8 2.5 22.9 lsoetes !acus!ris 0.0 0.0 0.1 1.1 4.0 4.1 9.5 18.8 Najasflexilis 1.8 2,3 4.8 1.6 2.7 1.2 0.2 16.6 i'olalnogetofl amplijiJliuy 0.4 3.3 5.2 4.6 1.2 0.2 0.0 14.9 Potamogcton gramineus 2.7 4.4 4.1 2.1 0.7 0.0 0.0 14.0 Myriophyllum tcnellum 4.3 7.2 0.8 0.1 0.0 0.0 0.0 12.3 Eriocaulon seplangulare 5.2 6.6 0.4 0.0 0.0 0.0 0.0 12.2 Myrioplivilum .Ipicatum 0.4 0.7 I.Y 3.2 2.4 1.0 11. I 9.6 Utricuiaria resupinala 3.1 4.9 1.3 0.1 11.(1 0.0 0.0 9.3 JunCU5 pelocarpus 2.9 4.1 0.5 0.5 11.(1 0.0 0.0 8.0 Potamogeton perfi)/iatus 1.0 2.2 2.3 1.4 0.5 0.1 0.0 7.5 Elodea canadensis 1.8 1.8 1.8 0.9 0.5 0.2 0.1 7.1 Sagittaria graminea 2.9 2.9 1.0 0.0 0.0 0.0 0.0 6.8 lsoetes echino.lpora 1.4 2.1 1.9 0.7 0.1 0.0 0.0 6.2 Heteranfhera duMa 0.6 2.0 1.3 0.7 0. I 0.0 0.0 4.8 Ranunculus /ongirostris 0.4 1.3 1.3 (J.6 11. I 11.(1 0.0 3.7 Elaline minima 1.8 1.5 0.1 0.0 0.0 0.0 0.0 3.4 Mexa/odonta beckii 0.1 0.1 0.6 1.0 0.5 0.6 0.1 3.0 Lobelia dortmanna 1.5 1.3 0.0 0.0 () .0 0.0 0.0 2.7 Eleocharis aciculari.I' 1.0 1.2 0.2 0.1 0.0 0.0 0.0 2.5 Potamof!,eton pusillus 0. I 0.4 0.5 0.7 0.2 0.1 0.1 2.1 Ranul1culus replans 0.9 1.2 0.1 0.0 0.0 0.0 0.0 2.1 PofamoKetol1 praelol1f!.us 0.0 0.0 0.2 0.5 0.9 0.4 0.0 2.0 PolamoKeton spirillus 0.4 0.5 0.3 0.2 0.1 0.0 0.0 1.6 A1yrioplryllum allernijlorum 0.6 0.7 0.2 0.0 0.0 0.0 0.0 1.5 Polamogetol1 zosterijormis 0.0 0.0 0.4 0.4 0.2 0.1 0.0 1.0 Suhularia aquafica 0.5 0.5 0.0 0.0 0.0 0.0 0.0 1.0 PolamoKeton vaseyi 0.1 0.2 0.2 0.4 0.1 0.1 0.0 1.0 SparKanium sp. 0.5 0.4 0.0 0.0 0.0 0.0 0.0 0.9 Najas Kua(/alupensis 0.1 0.4 0.3 0.0 0.0 0.0 0.0 0.8 P of amoKel on folioslIS 0.0 0.2 0.1 0.2 0.1 0.1 0.1 0.7 PolamoKetonfriesii 0.1 0.3 0.2 0.1 0.0 0.0 0.0 0.6 Potamof{eton epihvdrus 0.1 0.5 0.0 0.0 0.0 0.0 0.0 0.6 Nymphaea odorata 0.5 0.1 0.0 0.0 0.0 0.0 0.0 0.5 Sluckenia pectinata 0.1 0.5 0.0 0.0 0.0 0.0 0.0 0.5 Nuphar 'uleum 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.2 POlamow/on ohlus{folius 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.1 9 Fn:qut:m:y, or the number tributaries where each species was present, is an important measure or the distribution of species but does not consider the relative abundance of species within the overall population. Table 3 contains the species present and their depth distribution ranked in order of mean percent cover, TIlls ranking is a better measure of the dominani:e of" certain species and, in conjunction with frequency data, provides a more complete pic lure of aquatic plant cOlmnunity structure. Tn Figure 5, the depth distribution of the 10 most ablmdant species by mean percent cover is presented. Eurasian watennilfoil, ranked 10th by relative abundance, is included in the plot. A comparison of Figures 3 and 4 indicates that the 10 most ahundant species by frequency of occurrence arc not the same as the 10 most abundant species by relative percent cover. Seven of the ten species on the two lists, however. are tht: samc. Two of these species, Rlatine minima and lsoetes echin(),~p()ra, arc relatively small plants, yet they can be common in shallow waters, amI this is most likely why they rank anlOng the most frequent, but not for percent i:over. boetes lacustris, while 110t a common species by frequency of occurrence, forms a nearly monospecific carpet in depths of 5 to 7 meters at a number of sites. This density of growth makes it a common member of the plant community by mean percent cover. This demonstrates that certain species, while not appt:aring as often as others, can tend to dominate at the locations where they do occur. This species is also listed on the watch list for New York State. how!;:ver it is a common member of the I ,ake George aquatic plant community. 10 Figure 5. Mean percent cover and depth distribution of the 10 most common macrophyte species including Eurasian watemli1foil. ~ QI > 10.0 0 , 90 , <.l , ; r:: 8.0 I -QI ; I: 7.0 II QI , a. GO! r:: , r;vdc~ Idl"U:;II!~ .. ~.O I, f rioeaulon seplanpplar€ QI , :;; rotamogeto n amplltollus 40 ', i-'UidIllUgelv{1 Wdlflllll'U~ 3.0 !, , Myriophyllum tenelilim 2.0 , VJIIIS Ilerl,) arMIIC Jlkl • Myriophyllum PotamO{'flton mhhinsil spicatum M'I'{Io{lhyllum -"{llultllm Depth (m) 5-6 6-7 A comparison of the major species by frequency of occurrence reported lakewide for 1987-1988 (Madsen el aI, 1989) with the currenl list Cfable 2) shows few di!Tcrcnccs. Six of thc tcn most abundant specics arc thc samc. PotamoJ!,efun perfh/latus, P. pusillus, P. spirillus, and Jfyriuphyllum tenellum were not within the top ten species during the 1987 survey, but were ranked fifth, eighth, ninth, and tenth respectively in the 1991 survey. In 1999. of this group. only P. per.f()liatus and M lenellum were still ranked among the ten most abundant plant species in the north basin of Lake George. Eurasian watenniltoil was ranked 22ndand 19th by frequency of occurrence in the 1988 and 1993 surveys, respectivciy. By 1996, this ranking for milfoil had th u th dropped to 24 , the 1999 survey found it at 28 , , and the 2002 survey found it at 29 (Figure 6). TIle decrease in frequency of occurrence of Eurasian watermilfoil is most likely the result of hand harvesting of isolated populations of this species. II Figure 6. Rank of Eurasian Watemlilfoil by frequency of occurrence over the life of the tributary surveys in the North Basin of Lake George, NY. Rank of Milfoil by Frequency of Occurrence in the North Basin of Lake George, NY 40 30 ~c ~ . :: 20 o !E '" 10 o 1988 1993 1996 1999 2002 Survey Year Although the numher of samples is too few to suggest a statistieally.reliable rate of colonization, new sites continue to be colonized on a year to year basis. The occurrence of milfoil at sites which had been deared in previous years also indicates that continued surveillam.:e and maintenance of mil10il sites is nccessary. The more sobering indication from the recurrence of milfoil at previously harvested sites, is that there are no sites or ca.'ies to indicate any natural mortality or demise of small populations of Eurasian watennilfoil in Lake George. Although these populations may not expand for several years, dearly they arc not dying off on their own. 12 REFERIlNCI£S Eichler, L.W., and C. W. Boylen. 1997. A survey of tributaries to Lake George, New York for the presence of Eurasian w Eichler. L.W" R.I. Bombard amI C. W. Boylen. 1994. The Lake George Tributary Survey. Rensselaer Fresh Water lnstitute "'ceh. RCp01t 94-1. Rensselaer Polytechnic Institute, Troy, NY. King, R.W. and L. Lyman. 2002. Lake George Eurasian walermilfoil (Myriophyllum spicatum) 2002 management program, Final Report, October 23, 2002. Lycott Environmental, Inc., Southbridge, MA. 53pp. Madsen, J.D., L. W. Eichler and c:. W. Boylen. 1988. Vegetative Spread of Eurasian Watemlilfoil in Lake George, New York. J. Aquat. Plallt Mlmage. 26:47-50. Madsen, J.D .. J. W. Sutherland. J.A. Bloomfield, K.M. Roy, L.W. Eichler and C.W. Roylen. 1989. Lake George Aquatic Plant Survey. Final Report. New York State Department of Enviromnental Conservation, Albany, NY. May 19H9. Madsen. J.D., L.W. Eichler and C.W. Boylen. 1991. Lake George Eurasian Watermilfoil Survey, 1990 Report. Rensselaer Fresh Water Institute T cch. Report 91- Rensselaer Polytechnic Institute, Troy, NY. Ogden, R.C., .I.K. Dean, C. W. Roylen and R.R. Sheldon. 1976. Field Guide to the Aquatic Plants of Lake George, New York. Bull. No. 46, NYS Museum. NYS Ed. Dept., Albl!IlY, NY. 65pp. Young, S.M. 1993. New York Rare Plant Status List, New York Natural Heritage Program, Delmar, NY. February 1993. Young. S.M. 1999. New York Rare Plant Status List, New York Natural Heritage Program, Latham. NY. April 1999. ACKNOWI,«;()GM«;NTS This projed was supported by the Fund for Lake George through a grant to the Dafrin Fresh Water Institute. We gratefully acknowledge this support. Field assistance for this project was provided by Jeffrey Rartkowski, .Tohn Scrivo and Shannon Shaver. 13 APPENDIX A SITE LOCATIONS ,.i \ ~ ~ . • )/ , ! \ ~ I APPENDIXB MACROPHYTE COMMUNITY ASSESSMENT DATA Tr'lblll Spcci!O~ Depth Inlerval (m) O~1 '~2 2~3 3~4 4-5 5-6 6-7 CharalNilella sp. 10.0 2.5 100 2.5 2.5 750 Elatinc millIIna 2.5 2.5 I:lodea canadAnsis 2.5 2.5 Eriocaulon seplilngulare 2.5 100 Isu~llOS echinosporil 2.5 2.5 2,5 ISOAles lacustris 2.5 75.0 2.5 JUIlCllS plOlocarpus 2.5 2.5 Lobelia dorlmanna 2.5 2.5 Megalodonlli beckii 2.5 25 2.5 Myriophylillm tenellulll 2.5 37.5 Najas flexill;; 2.5 2.5 2.5 2.5 l-'otalllogAlon ampllfollus 2.5 10.0 2.5 Potamogelull gramineus 2.5 2,5 10,0 25 f-'otamogelon obtusifollus 2,5 Potamogeton p!Ortollatus 2.5 2.5 2.5 2.5 Potarllogeton robhinsii 2.5 10.0 2,5 Potamngeton splnllu~ 2.5 Ranunculus long'lrostr'ls 2.5 2.5 Vallisneri<'l ilmerican Tribut<'lry SurveyTransecl Data Date', 3-Sep-02 Site: T-IA Mossy Point [)epth Interval (rn) O~ 1 '~2 2-3 3·4 4" 5·6 '·7 MF.galodontil b!Ockil 2.5 2.5 CharalNltelia sp. 2.5 Elodea cilnadeilsis 10.0 10.0 F:riocaulon ~lOptangularfl 2.5 25 HeteranlhF.f Chara/Ni!ella sp. 2.5 25 ,., Eleoch3ris oClcul'lrIS ,., Eriocaulon septangulare 2.5 2' Isoetes echinospOI Tributary SUNey Tr,lIlsect Dodo:! DOlLe; 9-0ct-02 Site T-3 Gull Bay Species Depth InteMl1 (m) 0-1 1-' '-3 3-4 4-5 '-6 6-7 MlOg Mto'yalodonta beckii 2,5 10,0 2.5 10.0 2.5 ChC'lr Tribut8ry Survey Transect D Ch;Jr;JINltcila ~p, 2,5 2.5 10.0 10.0 10,0 Elaline minima 2.5 Eriocaulon sepl Sped!'!!'; Depth Intervill (m) 0-1 1-2 2-3 H 4-5 5-6 6-7 Ch Tr'lbul8ry Survey Transect Data DOlle: 6-Sep-02 ~Ite: T-6 Lamh Shanty B Species Dcplh Interval (m) 0-1 1-2 ;;'-3 3-4 4-5 5-6 6-7 CharalNitell SpeclCS Df'lplh Interval (m) 0-1 1-' 2-;) 3-4 4-5 5-6 6-7 CllOifa/Nitella sp. 2.' 2.5 25 10.0 10.0 2.5 '.5 Elatine minima 2.5 ,., FriocLlulon septi;!ngulare '.5 10.0 lsoetes echinospor.'l 2.5 ,., '.5 2.' lsoeles ILlcustns '.5 10.0 75 [) Juncus pelocarplJ;; 10.0 Lohelia dortm;Jnna '.5 2.' Myriophyllum tenAllum ,., 10.0 N Tributory Survey Transect Datil D;Jte: 7-Aug-02 Site: T-8 Gluff Hflad Sp(Ocies Depth Inlerval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 CharalNitell CharalNltella sp, 2.5 2.5 2.5 2.5 2.5 Flatine minima 25 2.5 I:::I~odlaris aClcul(lris 2.5 2.5 [Iodea canadfmsis 2.5 2.5 2,5 2.5 Eflocaulon scptangulare 2.5 2.5 Heteranthera dubia 2.5 2.5 Isoetes echinosporCJ 2.5 2.5 Juncus pelocarpus 2.5 2.5 Meg81odonta beckli 2.5 Myriophyllum tenellum 2.5 25 N8j8S flexilis 2.5 2,t) 10.0 2,5 2.5 Pulamugetun (Stuckema) pectir18ta 2.5 20,0 Potamogeton amplifolius 10.0 10.0 10.0 f-'ol"JIlug~lofl follusus 2.5 2.5 Potamogp.tnn gramineus 10.0 25 2.5 2.5 2.5 Polalllog~luJi p~!fuh(llus 2.5 2.5 2.5 Polamogelon !'llJsilllis 2,5 2.5 Pol Tnbutary Survf.:y I'TaJls~cl [)(ll" Date: 7-Aug-02 Site: T-l0 Sunset Bay Species Depth Interval (m) 0-1 1-2 '-3 3-4 4-5 5·6 6·7 CIl;;lrCJINltclla sp, 10,0 10.0 10,0 Elatine minima 2.5 Elcocha, is ac,culafl~ 2.5 2.5 Elodea canadensis 25 25 25 25 25 Eriocaulon sepl SpCCIOS Depth Interval {Ill} 0-1 1-2 2-3 3-4 4-5 5-6 6-7 CharalNitell<'l ~[l 2.5 2.5 2.5 EILlline minima 2.5 2.5 Eleocharis acicularig 10.0 2.5 Elodea cCJnCJdenSIS 2.5 2.5 Eriocaulon septangulare 10.0 2.5 Igop-Ies echinosporLl 25 2.5 2.5 2.5 Isoctes lacu~tfls 20.0 Juncus pelor: Tributary Survey Tran~Rd nata D SpRr.ip-s DP.pth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Ch;;JralNitetla 2,5 2.5 10,0 10.0 Elaline minima 2,5 2.5 EleochLlfis SpcCl!.l~ lJepth Inlerval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 c.;~laraINitella sp 10.0 2.5 2.5 2.5 10.0 Flatine mlnimJ 2.5 25 Eleocharis acicularis 2.5 10.0 Flodea cJnJdcnsis 2.5 2.5 2.5 25 Heteranthera dubia 2.5 2.5 2.5 Isop-Ies echinosporJ 2.5 2.5 10.0 2.5 Juncus pelocarpus 25 10.0 Lobelia dnrtm:lnna 2.5 Myriophyllulll allerTllllorum 2.5 2.5 Mllrio(;1hlltlum sp:icatum 2.5 2.5 2.5 75.0 75.0 ill 2.5 Myr'lophyllum tenellull1 2.5 25 NOljas Ilexilis 2.5 2.5 10.0 2.5 2.5 Polamogeton Tributary Survey Transect Data Dale: 30·Jul-02 Sile' T-lls Kitchal B<:Jy SpF.r.ies Depth Inlerval (m) 0-1 1-2 2-3 3-4 4-5 5-0 6-7 Cl1 Species Depth Interval (m) 0-1 1-2 2-' '-4 4-5 5-6 6-7 r:hClralNilella sp 2.5 2.5 2.5 2,5 2,5 25 2.5 E:.lalille IIllnima 2.5 2.5 [rioc<'Iulon septanaulare ~.5 10.0 Isoclcs eclllllo~pora 2.5 2.5 25 2,5 Isceles l<'Icustris /.5 750 Juncus pl.:locarpl1~ 10,0 Lobelia dortmann<'l 2.5 2.5 Myriophyllum tcnclluill 2.5 2.5 Najas tlexilis 25 2.5 2.5 2.5 2.5 2.5 Pntamogeton foliosus 2.5 Polamoyelon Iriesn Vi Potamog!'!tnn aramineus 2.5 2.5 Polamoyelon pusillus 2.5 2.5 2,5 2.5 Pnl<'lmogeton robbinsii 2.5 2.5 2.5 2,5 25 SulJUlarr(l (lquatlca 2.5 IJtnclllClria resupinala 10.0 Val1r311eria americana 7.5 2.5 10.0 10.0 10.0 10.0 Tnbulolly Survey Transect Data DatA: 8-Aug-02 Site: T-72 N. Halfway Island Species Uepth Interval (m) 0-1 1-2 2-' 34 4-5 5-6 6-7 Chara/Nitella sp 2.5 2.5 Elaline [IIlnima 2 G 2.5 ElorlACl r.anadensis 2.5 Eriocauloll septangulare 100 10.0 Heteranthera dubi<:l 2.5 Isoetes echinosporCl Vi 2.5 2.5 Isoclcs l Species Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 EI.:.lilie minima 2.5 Heteranthflra dubla 2.5 l!';oetes echlllu~pora 2.5 2.5 I~uetes lacllstri!'; 100 2.6 2.5 2.5 My:riO!;lh~z':ltum seicatum 2.5 2.5 NCljClS lIexilis 2.5 2.5 25 2.5 2.5 Pnt:lmogeton foliosus 2.5 2.5 Pulamogeton gr:lmineu$ 2.5 Poti'lmogeton pCJrrullatus 2.5 2.5 2.5 PolClmogetol1 robbinsii 25 2.5 2.5 2.5 Potamog8ton v Tributary Survey Transer.t nata Oale: 8-Aug-02 Site: T-72b Mid tliU 5 Mile Min bronk Species Depth Intflrval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Chi'lralNitella ~p. 2.5 25 Elalille minima 25 2.5 ISOfltflS echillospora 2.5 2.5 2.5 2.5 2.5 I~oetes lacuslris 2.5 2.5 Lobelii'l nortmann.:. 2.6 2.5 Najas flexllis 2.5 2.5 2.5 10.0 2.5 2.5 2.5 r'otamogeton gr3mlnCus 25 2.5 PolamogelOIl pusillus 2.5 2.5 Potamogetnn vaseyi 2.5 2.5 SparganlulTI sp. 2.5 Utricul<'lri<'l resupinata 100 2.5 Tributary Survey Tr Species Depth InlervClI (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Chara/Nllella sp. 25 2.5 2.5 2.5 2.5 2.5 25 Elatine minima 2.5 2.5 Eriocaulull septanglll:lre 100 10.0 Isoetes echinospor Species Depth Interval (m) 0-1 12 2-3 :1-4 4-5 5-6 6-7 CharalNitella sp. 2.5 10.0 10.0 2.5 2,5 2,5 Elatine Illrnillr Trrbutary Survey TransF".! Data Date: 30-Jul-02 Site: T-75 N. Steere Specr~s Depth Interval (m) 0-1 1-' 2-3 3-4 4-5 5-6 6-7 Chara/Nitell;] sp. 2.5 7.5 EI Ch Tnbut Chara/Nltell Tnbutary Survey Transect D<'lt<'l nate: 5-Sep 02 Site: T-79 N. Sabbath Day PI. Species Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 (;h Species LJt:pUl Inlerval (m) 0-1 1-2 2-3 3-~ 4-5 5-6 67 Chara/NitAII;! sp 2.5 2.5 10.0 '.5 Elatlnc minilila 2.5 25 Eriocaulon septal1gularA 2.5 10.0 Isoeles echlilospor Tributary SUlvey 'I fcHlseel Data Dale: 5-Sf'lp-02 ~Ile: T-81 Silver Bay Spt:cies Dcptllinlerval (fIl) 0-1 1-2 '-3 3-4 4-5 5-6 67 Chara/Nilella sp. 2-' 2.5 2.5 ,., 10.0 100 Elatine minima 2.' Elodea canadensis 2.5 '.5 2,5 Hf'lleranthera dubia ,., Isocte~ t:chlnospora 2,5 2.5 2.' JunclJs pelocarpu5 2.5 10.0 Lobelia uorlrll Species [)epth tnterv<:ll (Ill) 0-1 1-2 2-3 34 4-5 5-6 6-7 Chara/Nitella ~r, 2.5 10.0 10.0 20,0 Elatine IlllnimCl 2.t:) I:lodea canadensis 10.0 2.5 2.5 2.5 HRtf'!ranther<:l dubla 2.5 Isoele~ echillospora 25 2.5 Megalorlonta beckll 10.0 10.0 MYriophyllum lenellum 2.5 25 NaJas flexilis 2,t:) 2.5 Pntamogeton alllpilfoliu~ 2,5 2.5 Potailloyelun gramineus 10.0 2.5 10.0 f'otamogeton pf'!rfoliatus 10.0 2.5 2.5 Potamogeton praelullgus 2.5 I-'ulamogeton pusillus 2.5 25 POlilmngeton robblnsil 1U.U 10,0 Ranunculus longirostris 2.5 Sagittaria graminea 2.5 1'0,0 Sparg Tributary Survf'!Y Transect D SpHr.ies lJepth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Ch<:lr SpcciL's Depth Interval (m) 0·1 1·2 2-3 H 4·5 5·6 6·7 ChCi! Tributary Survey Transect Data O;;ltC: O-Oel-02 Sile: T 84 Cape Corl Village o . .>[If'lCI8S Depth Inlerval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Cll'Jf Species Depth Interv<'ll (m) 0-1 1-2 2-3 3-4 '-5 5-6 0-7 Ctlor;;/Nltella sp. 2,5 2.5 2.5 [iatinfl minima 25 Eleoch Trihutill)' Survey Transect lJata Oat!'!: 3-Sep-02 Site. 1-(\(\ Rogers Beach - S Species Depth Interval (m) 0-1 2 2-3 3-' 4-5 5-6 6-7 Chara/Nitell<'l sp. 2.5 2.!i 2.5 2.5 Flatine minlillil 2.5 2.5 2.5 ~Ieu~haris aciculari~ 2.5 [Iodfl<'l r.:JnadensI5 2.5 2.5 2.5 Hctcranltlera dubia 2.5 10.0 10.0 2.5 Isoetes echinospora 2.5 2.5 Myriophyllum t Sf.!~cies Dcpth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-' Chara/Nitell<'l ~p. 25 2.5 2.5 10.0 10.0 20.0 EICltine mlnlm8 2.5 2.5 Elod~ll canadensis 2.5 25 10.0 10,0 2.5 2.5 Eriocaulon ~"'rtangul<:lrc 10.0 Heler3nthcr8 duuill 2.5 10,0 10.0 2.5 I:;oetes echinospor Tributary Sllrvey Tr Sper.ies lJepth Interv81 (m) 0-1 12 '-3 3-4 4-5 5-6 6-' CllOirOiINitella 25 2.5 10.0 10.0 Elode<'l r.:Jnadensis 2,5 10.0 200 25 HetC'Wllll~ra dubia 100 10,0 2.5 lsoetes echinnspor Species Depth Interval {m} 0-1 1-2 2-3 '-4 45 5-6 6-7 Chara/Nitella sp 2.5 2.5 2.5 flodea c8n8denSlS 2.5 2_5 2.5 bioo.:aulon seplangulare 37.S 20.0 2.5 HAtf'lranthera dubi8 2.5 Juncu~ pelocarpus 2.5 2.5 Lobeliil nortmilnna 2.5 2.5 Mynophyllum OlllclnlnllJUl1i 2.5 25 Myrrophyllum tenellum 10_0 10.0 2.5 Potamogetnn ilmplifolius 2.5 PotOllllogc\on grarnilleus 2_5 25 2.5 Potamogeton perfotiilllls 25 2.5 Potamogeton robbinsil 2.[; Rallullculus longirostris 2.5 2.5 R::lIllJllr.lllus replans 2.5 2_5 UIII(;utaria resupinata 7_5 Vallisneria arnf'lriCClnil 2.5 10.0 2.5 Illbulary Survey Transect Data Date: 3-Scp-02 S·lle: T-90 Rogers Rock - N Species Depth Interval (m) 0-1 1-2 2-' 3-4 4-5 5-6 6-7 CharalNitelia sp 2_5 2.5 10_0 20.0 "Ialille minima 2.5 2.5 Elodea canMenslS 2_5 7.5 2_5 2.5 Heleranlhera dubia 2.5 2.5 Isoele~ f'lr.hinospora 2.5 2_5 Isoeles l Species Depth Interval (m) O~1 1-2 2-3 3~4 4~5 5~6 6~7 ChalL1lN,lciia sp. 25 2.5 25 10.0 I:latrne minim Tributary Survey Tr8nsect Dat Species Derth Interv Chara/Nitella sp. 10.0 2.5 2.5 25 10.0 10.0 10.0 Et Species Depth Interval (m) O~1 '~2 2-3 H 45 5-0 6~7 EI