2006 Survey of Tributaries for Eurasian Watermilfoil

A SURVEY OF TRIBUTARIES TO LAKE GEORGE, NEW YORK FOR THE PRESENCE OF EURASIAN WATERMILFOIL

prepared for The Fund for Lake George

Lawrence W. Eichler Research Scientist

Laurie E. Ahrens-Franklin Research Technician

& Charles W. Boylen Associate Director

Darrin Fresh Water Institute 5060 Lakeshore Drive Bolton Landing, NY 12814 Rensselaer Polytechnic Institute Troy, NY 12180-3590

DFWI Technical Report 2006-7

i TABLE OF CONTENTS

The Survey of Lake George Tributaries for Eurasian watermilfoil – 2006

Executive Summary iii

Introduction 1

Methods 1

Results and Discussion 3

References 11

Acknowledgements 11

Appendix A. Site Locations

Appendix B. Macrophyte Community Assessment data

EXECUTIVE SUMMARY

A survey of tributary deltas in the southern portion of the Lake George basin was conducted in 2006 to assess the extent of Eurasian watermilfoil (Myriophyllum spicatum L.) infestation. The Darrin Fresh Water Institute conducted the project with financial support from the Fund for Lake George. Similar surveys were completed at approximately 3-year intervals commencing in 1988, as reference points. Delta areas were chosen as readily identifiable points that historically harbor diverse assemblages of native aquatic plants.

Results of these surveys can be used to approximate the rate of spread of Eurasian watermilfoil (EWM) through the Lake George basin. In 1988, when surveys were initiated, 22 percent of the sites in the northern third of the Lake George basin were found to have EWM. By 1990, this percentage had increased to 39 percent with a gain of 7 new EWM sites. In 1993, the percentage of tributary sites with active EWM populations had declined slightly to 37 percent. The decrease was due to hand harvesting activities at 5 locations in this portion of the Lake George basin. Discovery of 4 new EWM sites during the 1993 survey, however, reduced the overall impact of management activities to a net loss of one active EWM site. In 1996, a total of 17 sites (42%) had EWM present, with 2 sites (5%) producing EWM for the first time. Of the two new EWM sites, both were restricted to a few plants, which were removed. Results from the 1999 survey showed a slight increase to 44% of the sites colonized by EWM. All of the new sites were restricted to only a few milfoil plants, which were removed. EWM was reported at 42% of the sites surveyed in 2002 and 2005, a slight decline from 1999. This stability is attributed to hand harvesting of EWM in prior years.

Management efforts to date have been implemented at 137 of 149 known EWM locations throughout Lake George. These efforts have reduced the EWM biomass in these locations; however, EWM has only been eliminated at a handful of sites and reintroduction at these locations is highly probable. Thus maintenance becomes critical following initial management. At this time, EWM is ranked 8th by relative abundance (a function of cumulative percent cover) in the north basin and 23rd by frequency of occurrence for the 42 species found in this survey. The fact that EWM has reached this level of abundance is testament to the plant’s ability to spread rapidly and to outcompete native species. Maintenance will require site visits yearly or every other year to harvest regrowth of EWM.

Although the number of replicates is limited for development of a statistically reliable rate of colonization, new sites continue to be colonized on a year-to-year basis. Expansion of EWM at the 41 tributary sites over the eighteen-year span of the study is approximately 4 new sites per year, or a 9% annual rate of colonization. The occurrence of EWM at sites that had been cleared in previous years also indicates that continued surveillance and maintenance of EWM sites is necessary. The more sobering indication from the recurrence of EWM at previously harvested sites is that there is little evidence to indicate any natural mortality or demise of small populations of EWM in Lake George. Although these populations may not expand for several years, clearly they are not dying off on their own.

Tributary surveys demonstrate the need for continued management of EWM in Lake George. Management programs currently encompass several different techniques reflective of different stages of EWM development. Tributary surveys provide a means of mapping EWM colonization in Lake George, while management programs limit the spread of EWM once sites have been located. Increased public awareness of the effects of growth and spread of EWM on the Lake George ecosystem can help reduce further introduction.

Introduction

Streams entering Lake George, with nutrients and suspended sediments derived from the terrestrial portion of the basin and deposited on their deltas, are prime locations for the continued establishment and re-establishment of Eurasian watermilfoil (Myriophyllum spicatum L.). Delta areas are also disturbed habitats, as a result of sedimentation of terrestrially derived materials and scouring of existing sediments at times of accelerated runoff. The combination of sediment conditions and habitat disruption make tributary deltas prime locations for Eurasian watermilfoil infestation. Because human activity in the Lake George basin has historically exacerbated water conditions in the south basin, the rate of establishment and spread of milfoil has been of particular concern in the management of Eurasian watermilfoil.

A survey of all the tributaries in the basin was performed as part of the 1987-88 Lake George Aquatic Plant Survey (Madsen et al, 1989). Around the entire lakeshore, there are 128 listed stream tributaries (Madsen et al, 1989). The survey provided a procedure for finding new sites with Eurasian watermilfoil, including establishment of a regular search pattern for milfoil sites to ascertain the relative distribution of milfoil among the native plant communities in Lake George.

In order to balance the number of tributary sites surveyed in each year and stabilize the cost of the survey, south basin tributaries were divided into two groups in 1991. With approximately 45 tributaries in each group, a three-year cycle of surveys was established with a south, central and north component of nearly equal number of tributaries. The tributaries in the north basin are the focus of the current survey.

The north basin tributary survey was repeated in 1989 in order to provide information on the rate of colonization of Eurasian watermilfoil (Madsen et al, 1990). Since these are readily located sites for which the presence or absence of Eurasian watermilfoil was known for 1988, 1990, 1993, 1996, 1999 and 2002, these sites were revisited in 2005 to determine 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 between July 7 and September 23, 2005. Surveys consisted of swimming a 100-meter segment of shoreline from the water's edge to the outer edge of the littoral zone. Diver swimover transects were also completed at each site in order to characterize the macrophyte (aquatic plant) community present. Divers skilled in plant identification estimated the abundance of all aquatic plant species in each one-meter (3 ft) 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% Present P 15% to 25% cover 20.0% Occasional O 5% to 15% cover 10.0% Rare R less than 5% cover 2.5%

Percent cover data provides both average depth distribution of the plants present and an estimate of relative abundance of the species at the tributary sites. This information is also important for future management decisions concerning milfoil control alternatives and permit 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 are provided in Appendix A.

Figure 1. Map of Lake George showing the area of the Tributary surveys. The 2005 survey included the tributaries of the north section.

Results and Discussion

The current survey included the tributaries located in the central portion of the Lake George basin (45 sites). The northern and southern portions of the lake basin were completed in 2002 and 2003, respectively. The results of the central basin tributary surveys for 1987, 1989, 1992, 1995, 1998, 2001 and 2004 are presented in Table 1. Methodologies employed for the five surveys are the same. For each site, the tributary number and site name is given. If Eurasian watermilfoil was found, the milfoil site number is also indicated. Aquatic plant management efforts keyed to hand harvesting, suction harvesting and benthic barrier installation have been employed since 1987. All milfoil sites in the current survey have been the subject of management efforts, with specific efforts based on the extent of milfoil growth. Paradise Bay (M-41) has been excluded from management efforts in recent years, due to its selection as a potential experimental site for herbicide application. Maps depicting the locations for all sites are included in Appendix A.

Table 1. Tributary survey sites and the presence (yes) or absence (no) of Eurasian watermilfoil. M # is a sequential coding of sites with Eurasian watermilfoil.

Tributary SITE NAME 2005 2002 1999 1996 1993 1990 1988 Milfoil # #

T-1 Opposite Rogers Rock N N N N N N N M-13 T-1A Mossy Point Y Y Y Y Y Y Y T-2 Glenburnie N N N N N N N M-48 T-3 Gull Bay Y Y Y Y Y Y Y M-47 T-3A Smith Bay Y N Y Y Y Y Y M-49 T-4 S. Burnt Point N N N N N N Y M-50 T-5 Clark Hollow Brook Y Y Y Y N Y Y M-132 T-6 Shanty Bay Creek Y N Y Y N N N M-101 T-7 Brook N. of Green Point N Y Y Y Y N N M-67 T-8 Bluff Head Creek Y Y N Y Y Y N M-63 T-9 Brook By Agnes Island Y Y Y Y Y Y N M-6 T-10 Sunset Bay Trib. Y Y Y Y Y Y Y M-68 T-10A Rock Dunder Island Brook N Y Y Y Y Y N M-54 T-11 Cook Bay, Huletts Landing N N N N N Y Y M-69 T-11S Kitchal Bay, Huletts Landing N N N N N Y N M-51 T-11N Eichlerville Bay, Huletts Landing Y Y Y Y Y Y Y M-70 T-71 S. Trib. W. of Halfway Island N N Y N N Y N T-72 N. Trib. W. of Halfway Island N N N N N N N M-102 T-72A S. Trib 5 mile Mtn Brook Y Y Y N Y N N T-72B Mid. Trib 5 mile Mtn Brook N N N N N N N M-130 T-73 N. Trib 5 mile Mtn Brook N Y Y N N N N

Tributary SITE NAME 2005 2002 1999 1996 1993 1990 1988 Milfoil # #

T-74 S. Steere Island Brook N N N N N N N M-131 T-75 N. Steere Island Brook Y N Y N N N N T-76 S. Route 9N Rest Area N N N N N N N T-78 Sabbath Day Point Brook N N N N N N N T-79 N. Sabbath Day Point Brook N N N N N N N T-80 North Bass Bay N N N N N N N T-81 Silver Bay N N N N N N N T-82 Van Buren Bay Brook N N N N N N N T-82A Stark Point Wetland N N N N N N N T-83 South Jenkins Brook N N N N N N N M-115 T-84 Cape Cod Village Brook N N N Y N N N M-99 T-85 Holman Hill Creek Y Y Y Y Y N N M-71 T-86 Hague Brook Y Y Y Y Y Y N M-100 T-87 Temple Island Brook N Y N Y Y N N M-150 T-88 S. Trib. Cooks Bay Y N N N N N N M-72 T-89 S. Cooks Bay Y Y Y N Y Y N M-52 T-90 N. Trib Cooks Bay N N N Y N Y Y M-129 T-91 S. Camp Sagamore Y Y Y N N N N M-73 T-91A Brook in Dark Bay Y Y N Y Y Y N T-101 North of Hague Brook N N N N N N N

Total Sites with EWM 17 17 18 17 15 16 9

The results of the seven surveys are further summarized in Figure 2. In the 1988 survey, a total of 9 (22%) of the 41 sites had Eurasian watermilfoil. In 1990 the total increased to 16 (39%) of the 41 sites surveyed having Eurasian watermilfoil. 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 this number had increased to 18 (44%). Of the 41 sites visited, milfoil was found for the first time at 3 (7%) of the tributary sites in 1999. In 2002 and 2005, EWM was found at 17 (42%) of the sites surveyed. No new EWM sites were found in 2002, and a single new site was reported in 2005. Four (10%) of the sites at which milfoil occurred were positive for the invasive species since the initial survey in 1988. Ten sites (25%) had milfoil present in previous surveys, but not in the 2005 survey. Fourteen of the 26 sites that were positive for milfoil by 2002 had been cleared by hand-harvesting or other methods prior to 2005, and have been positive on least one occasion since the initial eradication. Thus not only initial colonization but also re-colonization of tributary sites by Eurasian watermilfoil is occurring in Lake George. The rate of colonization, however, is variable from year to year and between the three portions of the survey.

Figure 2. Tributary Sites with Milfoil in the North Basin of Lake George, NY

Tributary Sites with Milfoil in the North Basin of Lake George, NY 40 New Sites Total Sites 30 Current Sites

10 Number of Sites

0 1988 1990 1993 1996 1999 2002 2005

The statistics of most interest are the number of sites that had Eurasian watermilfoil during one survey year, but not during the follow-up surveys. Eight sites had milfoil in only 1 of the 7 survey years supporting the contention that hand harvesting small populations of milfoil can eliminate this species. Four of the sites surveyed in 2005 have had a milfoil population since the first tributary survey in 1988. Those sites are: Mossy Point (M-13), Gull Bay (M-48), Sunset Bay Tributary (M-6), and Eichlerville Bay (M- 51). Two of these sites were hand harvested for milfoil removal during each of the surveys, and benthic barrier was installed in Sunset Bay. Eichlerville Bay was selected as a control site for an experimental herbicide application and management efforts were discontinued in 1993. All of these sites have well established EWM populations in the general vicinity from which the plants may have been reintroduced. Twenty-three sites supported milfoil in 2 to 6 of the survey years, suggesting that not only initial colonization but also recolonization of tributary sites by Eurasian watermilfoil is occurring in Lake George. The rate of colonization, however, is variable from year to year and between the four portions of the survey. To date, we have no evidence that the loss of Eurasian watermilfoil populations at specific sites in Lake George can be attributed to natural mortality.

Of the 50 species of submersed aquatic plants identified for Lake George (Ogden et al, 1976, Madsen et al, 1989), 42 were found at the tributary sites in the north basin. Four of these species are on the New York State Rare Plant List (Young, 2005) or associated Watch Lists: Isoetes lacustris, Subularia aquatica, Megalodonta beckii and Myriophyllum alterniflorum. This is particularly important for plant management considerations given the impact that a given management technique 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 also indicative of the suitability of these sites for aquatic plant growth and conversely, the high probability of milfoil infestation at these sites.

Table 2. Frequency of occurrence of all macrophyte species at the tributary sites (n=41). Species are listed in order of decreasing frequency.

Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7 All

Potamogeton gramineus 38 40 35 25 11 1 0 40 Vallisneria americana 30 34 35 27 13 4 0 40 Chara/Nitella spp. 37 34 29 23 13 6 1 38 Myriophyllum tenellum 32 32 18 0 0 0 0 36 Najas flexilis 24 29 30 22 11 5 0 34 Eriocaulon aquaticum 31 30 11 1 0 0 0 33 Elatine minima 29 29 3 0 0 0 0 31 Juncus pelocarpus 26 27 11 0 0 0 0 31 Elodea canadensis 25 27 24 20 12 6 0 30 Potamogeton robbinsii 5 17 23 20 13 7 0 28 Potamogeton perfoliatus 16 23 23 20 7 2 0 27 Sparganium sp. 27 25 3 1 0 0 0 27 Eleocharis acicularis 23 19 1 0 0 0 0 26 Sagittaria graminea 20 16 6 0 0 0 0 24 Isoetes echinospora 19 20 19 9 0 0 0 23 Lobelia dortmanna 22 17 4 0 0 0 0 23 Ranunculus longirostris 12 20 16 9 2 0 0 23 Potamogeton amplifolius 3 13 20 18 7 2 0 22 Potamogeton pusillus 12 17 11 8 2 2 1 21 Zosterella dubia 15 17 13 10 1 0 0 21 Potamogeton spirillus 10 12 6 1 0 0 0 17 Ranunculus reptans 14 17 1 0 0 0 0 17 Myriophyllum spicatum 9 12 9 9 3 0 0 15 Utricularia resupinata 11 12 2 0 0 0 0 13 Megalodonta beckii 1 5 8 5 1 1 0 10 Myriophyllum alterniflorum 7 7 0 0 0 0 0 9 Potamogeton foliosus 3 8 7 2 0 0 0 9 Potamogeton vaseyi 4 7 5 4 1 0 0 9 Potamogeton zosteriformis 2 4 5 5 3 0 0 9 Potamogeton friesii 4 4 2 0 0 0 0 6 Potamogeton praelongus 0 1 1 1 2 1 0 5 Subularia aquatica 3 3 0 0 0 0 0 4 Fontinalis flos-aquae 3 2 1 0 0 0 0 3 Potamogeton richardsonii 2 1 0 1 0 0 0 3 Sagittaria cuneata 3 1 0 0 0 0 0 3 Najas guadalupensis 0 1 2 1 0 0 0 2 Nymphaea odorata 2 1 0 0 0 0 0 2 Isoetes lacustris 0 0 0 0 1 1 1 1 Potamogeton crispus 0 1 0 0 0 0 0 1 Potamogeton epihydrus 1 0 0 0 0 0 0 1 Potamogeton illinoensis 0 0 1 1 0 0 0 1 Scirpus subterminalis 1 0 0 0 0 0 0 1

In Table 2, the species present and their depth distribution are ranked in order of the frequency for which they appeared at the tributary sites. The depth distribution of the ten most frequently occurring species is presented in Figure 3. Depth distribution and species richness remains comparable to that reported in previous surveys of the tributaries of the central basin.

Figure 3. Percent frequency and depth distribution of the 10 most common macrophyte species and Eurasian watermilfoil (Myriophyllum spicatum).

100%

90%

80%

70% 60% Vallisneria americana 50% Elodea canadensis Eriocaulon septangulare 40% Myriophyllum tenellum Chara/Nitella spp.

Frequency of Occurrence 30% Potamogeton gramineus 20% Juncus pelocarpus 10% Najas flexilis 0% Potamogeton robbinsii 0-1 1-2 Elatine minima Myriophyllum 2-3 3-4 Myriophyllum spicatum spicatum 4-5 Depth (m) 5-6 6-7

Frequency of occurrence, or the number of tributaries where each species was present, is an important measure of the distribution of a species but does not consider the relative abundance of that species within the overall population. Table 3 lists the species present and their depth distribution ranked in order of mean percent cover. This ranking is a better measure of the dominance of certain plants, and in conjunction with frequency data, provides a more complete picture of aquatic plant community structure. In Figure 4, the depth distribution of the 10 most abundant species is presented. A comparison of Figures 3 and 4 indicates that the 10 most abundant species by frequency of occurrence are not the same as the 10 most abundant species by mean percent cover. Seven of the ten species on the two lists, however, are the same. One notable exception is Potamogeton amplifolius. Potamogeton amplifolius, while not a common species by frequency of occurrence, accounts for approximately 10% of the lake bottom coverage in this region of the lake. The large in stature, often in excess of 1.5 meters in height, and

Table 3. Mean percent cover of all macrophyte species at the tributary sites (n=41). Species are listed in order of decreasing abundance.

Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7 All Vallisneria americana 3.90 5.43 6.65 5.73 1.71 0.43 0.00 23.84 Potamogeton robbinsii 0.49 1.22 2.93 5.49 4.02 3.11 0.00 17.26 Najas flexilis 1.46 2.50 3.48 3.05 1.59 0.49 0.00 12.56 Charophytes 2.80 2.80 2.68 1.95 1.34 0.91 0.06 12.56 Potamogeton gramineus 2.50 3.54 3.05 2.07 0.67 0.06 0.00 11.89 Eriocaulon aquaticum 3.90 4.82 1.22 0.06 0.00 0.00 0.00 10.00 Potamogeton amplifolius 0.37 1.77 3.05 3.60 0.79 0.30 0.00 9.88 Elodea canadensis 2.07 2.38 2.20 1.77 0.73 0.37 0.00 9.51 Myriophyllum tenellum 2.93 4.02 1.16 0.00 0.00 0.00 0.00 8.11 Myriophyllum spicatum 0.55 0.73 2.44 1.95 1.95 0.00 0.00 7.62 Potamogeton perfoliatus 1.16 1.83 1.59 1.40 0.43 0.12 0.00 6.52 Juncus pelocarpus 1.95 2.38 0.85 0.00 0.00 0.00 0.00 5.18 Isoetes echinospora 1.34 1.22 1.71 0.73 0.00 0.00 0.00 5.00 Zosterella dubia 1.28 1.40 0.79 0.61 0.06 0.00 0.00 4.15 Elatine minima 1.77 1.77 0.18 0.00 0.00 0.00 0.00 3.72 Ranunculus longirostris 0.73 1.22 0.98 0.55 0.12 0.00 0.00 3.60 Sparganium sp. 1.65 1.52 0.18 0.06 0.00 0.00 0.00 3.41 Utricularia resupinata 1.22 2.07 0.12 0.00 0.00 0.00 0.00 3.41 Sagittaria graminea 1.59 1.34 0.37 0.00 0.00 0.00 0.00 3.29 Potamogeton pusillus 0.73 1.04 0.67 0.49 0.12 0.12 0.06 3.23 Eleocharis acicularis 1.59 1.34 0.06 0.00 0.00 0.00 0.00 2.99 Lobelia dortmanna 1.34 1.04 0.24 0.00 0.00 0.00 0.00 2.62 Ranunculus reptans 1.22 1.22 0.06 0.00 0.00 0.00 0.00 2.50 Potamogeton spirillus 0.61 0.73 0.37 0.06 0.00 0.00 0.00 1.77 Megalodonta beckii 0.06 0.49 0.49 0.30 0.06 0.06 0.00 1.46 Potamogeton vaseyi 0.24 0.43 0.30 0.24 0.06 0.00 0.00 1.28 Isoetes lacustris 0.00 0.00 0.00 0.00 0.24 0.91 0.06 1.22 Potamogeton foliosus 0.18 0.49 0.43 0.12 0.00 0.00 0.00 1.22 Potamogeton zosteriformis 0.12 0.24 0.30 0.30 0.18 0.00 0.00 1.16 Myriophyllum alterniflorum 0.61 0.43 0.00 0.00 0.00 0.00 0.00 1.04 Nymphaea odorata 0.55 0.06 0.00 0.00 0.00 0.00 0.00 0.61 Potamogeton friesii 0.24 0.24 0.12 0.00 0.00 0.00 0.00 0.61 Sagittaria cuneata 0.37 0.06 0.00 0.00 0.00 0.00 0.00 0.43 Fontinalis flos aquae 0.18 0.12 0.06 0.00 0.00 0.00 0.00 0.37 Potamogeton praelongus 0.00 0.06 0.06 0.06 0.12 0.06 0.00 0.37 Subularia aquatica 0.18 0.18 0.00 0.00 0.00 0.00 0.00 0.37 Najas guadalupensis 0.00 0.06 0.12 0.06 0.00 0.00 0.00 0.24 Potamogeton richardsonii 0.12 0.06 0.00 0.06 0.00 0.00 0.00 0.24 Potamogeton illinoensis 0.00 0.00 0.06 0.06 0.00 0.00 0.00 0.12 Potamogeton crispus 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.06 Potamogeton epihydrus 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.06 Scirpus subterminalis 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.06

broad leaves of this species, produce extensive bottom coverage by a small number of plants. The growth habit of Myriophyllum spicatum, forming dense stands where it 10

becomes established, also results in this species being ranked higher by percent cover than frequency of occurrence. These two examples demonstrate that certain species, while not appearing as often as others, can tend to dominate at the locations where they do occur.

Figure 4. Mean percent cover and depth distribution for the 10 most common macrophyte species, including Eurasian watermilfoil (Myriophyllum spicatum).

7.00

6.00

5.00

4.00 Potamogeton amplifolius Potamogeton robbinsii 3.00 Potamogeton gramineus Mean Percent Cover Charophytes 2.00 Najas flexilis Eriocaulon aquaticum 1.00 Elodea canadensis 0.00 Myriophyllum tenellum 0-1 1-2 Myriophyllum spicatum 2-3 3-4 Vallisneria americana 4-5 Depth (m) 5-6 6-7

A comparison of the major species by frequency of occurrence reported during prior surveys (Eichler et al. 1997; 2000; 2003) with the current list (Table 2) shows few differences. Eight of the ten most abundant species are the same. Isoetes echinospora and Potamogeton perfoliatus were not among the top ten species during the 2005 survey, but were ranked eight and sixth respectively in the 1999 and 2002 surveys. Eurasian watermilfoil was ranked 22nd and 19th by frequency of occurrence in the 1988 and 1993 surveys, respectively. In 1996 and 1999, Eurasian watermilfoil ranked 24th and 28th by frequency of occurrence. In recent surveys, EWM ranked 26th in 2002 and 23rd in 2005. While Eurasian watermilfoil frequency of occurrence has not declined appreciably by frequency of occurrence, the fact that it has not expanded its coverage is encouraging. This relationship also coincides with the mean percent cover between survey years. In 1996, EWM was listed as sixth in terms of mean percent cover. By the 1999 and 2002 11

surveys, EWM had declined to 18th on the list. In 2005, EWM was ranked 10th by mean percent cover. While the number of locations where Eurasian watermilfoil is found in this section of the lake and the relative amount of lake bottom covered by this species has remained stable between survey years, the limited presence of EWM in this region of the lake may be attributed to management efforts. Hand harvesting scattered populations of Eurasian watermilfoil and suction harvesting or application of benthic barrier for areas of dense growth of Eurasian watermilfoil appears to have slowed the expansion of this species.

Figure 5. Mean percent cover of common native aquatic plant species and Eurasian watermilfoil.

Comparison of Native Macrophytes and Milfoil

Potamogeton 50.0 gramineus 45.0 Potamogeton 40.0 perfoliatus 35.0 Potamogeton 30.0 amplifolius

25.0 Potamogeton 20.0 robbinsii

15.0 Vallisneria americana Mean percent cover 10.0 5.0 Myriophyllum spicatum 0.0 1993 1996 1999 2002 2005

Long-term data on species richness may suggest a relationship to frequency of occurrence of EWM. Since 1990, the number of tributary sites in the north basin with milfoil present has increased by 6%. This small increase is most probably due to management efforts employed to control EWM, given that EWM invasion and spread is typically very rapid. Over this same time frame, the total number of species observed in tributary surveys has also remained stable (from 37 to 43 species present per year), indicating a limited impact of EWM growth on species richness. The negative impact on species richness of dense growth of EWM has been well documented in Lake George, while the current survey results support the positive impact of milfoil removal on native species richness. Variability in the growth of aquatic plants however is also attributed to climactic conditions and cyclical growth patterns. From Figure 5, it is apparent that mean percent cover results for most species have varied consistently over the years of survey, with 1993 and 1999 particularly good growing years for all species and 1996 and 2005 poor ones. Seasonal variability and cyclic growth patterns place limits on the ability to detect impacts associated with the growth of Eurasian watermilfoil. In order to understand the impact of Eurasian watermilfoil growth on native species abundance, long-term evaluations are necessary. 12

Figure 6. Species richness and EWM frequency of occurrence for tributary sites in the north basin.

30 Total number species

Number sites with milfoil 20 Tributary Sites & Species Richness 10

0 1988 1990 1993 1996 1999 2002 2005

Although the number of replicates is too few to suggest a statistically reliable rate of colonization, new sites continue to be colonized on a year-to-year basis. The occurrence of milfoil at sites that had been cleared in previous years also indicates that continued surveillance of milfoil sites is necessary. The more sobering indication from the recurrence of milfoil at previously harvested sites is that there are no sites or cases to indicate any natural mortality or demise of small populations of Eurasian watermilfoil in Lake George. Although these populations may not expand for several years, clearly they are not dying off on their own.

REFERENCES

Eichler, L.W., and C.W. Boylen. 1996. The Lake George Tributary Survey. Darrin Fresh Water Institute Tech. Report 96-3. Rensselaer Polytechnic Institute, Troy, NY. Eichler, L.W., E.A. Howe and C.W. Boylen. 1998. A Survey of Eurasian watermilfoil Associated with Tributaries in the Lake George Basin. DFWI Technical Report 98-4. Darrin Fresh Water Institute, Bolton Landing, NY.

Eichler, L.W., E.A. Howe and C.W. Boylen. 2002. A Survey of Tributaries in Lake George, New York for Eurasian watermilfoil. DFWI Technical Report 2002-3. Darrin Fresh Water Institute, Bolton Landing, NY. Madsen, J.D., L.W. Eichler and C.W. Boylen. 1988. Vegetative Spread of Eurasian Watermilfoil in Lake George, New York. J. Aquat. Plant Manage. 26:47-50. Madsen, J.D., J.W. Sutherland, J.A. Bloomfield, K.M. Roy, L.W. Eichler and C.W. Boylen. 1989. Lake George Aquatic Plant Survey. Final Report. New York State Department of Environmental Conservation, Albany, NY. May 1989. Madsen, J.D., L.W. Eichler and C.W. Boylen. 1991. Lake George Eurasian Watermilfoil Survey, 1990 Report. Rensselaer Fresh Water Institute Tech. Report. Rensselaer Polytechnic Institute, Troy, NY. Mitchell, R.S. 1986. A checklist of New York State plants. Bulletin No. 458, New York State Museum, NYS Education Department, Albany, NY. 272pp. Ogden, E.C., J.K. Dean, C.W. Boylen and R.B. Sheldon. 1976. Field Guide to the Aquatic Plants of Lake George, New York. Bull. No. 46, NYS Museum, NYS Ed. Dept., Albany, NY. 65pp. Young, S.E. 2004. New York Rare Plant Status List, New York Natural Heritage Program, Delmar, NY. May 2004. http://www.dec.state.ny.us/website/dfwmr/heritage/plants.htm

ACKNOWLEDGMENTS

This project was supported by the FUND for Lake George through a grant to the Darrin Fresh Water Institute. We gratefully acknowledge their support. Field assistance for this project was provided by Tiffini Burlingame, Jessica Bulova and Kaley Bell.

APPENDIX A

SITE LOCATIONS

Appendix A – Site Maps A-1

APPENDIX B

PERCENT COVER DATA

Eurasian Watermilfoil (Myriophyllum spicatum) is bold and underlined.

Tributary Survey Transect Data 16-Sep-05 Site: T-1 Opposite Rogers Rock

Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 Elatine minima 2.5 2.5 Eriocaulon aquaticum 2.5 2.5 Isoetes echinospora 2.5 2.5 2.5 2.5 Juncus pelocarpus 2.5 2.5 Myriophyllum tenellum 2.5 2.5 Najas flexilis 2.5 2.5 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 Potamogeton robbinsii 2.5 2.5 Potamogeton spirillus 2.5 2.5 Sparganium sp. 2.5 2.5 Vallisneria americana 2.5 2.5 2.5 2.5

Tributary Survey Transect Data 16-Sep-05 Site: T-1A Mossy Point Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 Eleocharis sp. 2.5 Elodea canadensis 2.5 2.5 Eriocaulon aquaticum 2.5 2.5 Juncus pelocarpus 2.5 2.5 Megalodonta beckii 2.5 10 Myriophyllum spicatum 2.5 2.5 Nymphaea odorata 20 2.5 Potamogeton amplifolius 10 10 Potamogeton gramineus 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 Potamogeton pusillus 2.5 2.5 Potamogeton richardsonii 2.5 Potamogeton robbinsii 10 10 Potamogeton vaseyii 2.5 Ranunculus longirostris 2.5 2.5 Sagittaria graminea 2.5 2.5 Sparganium 2.5 Vallisneria americana 2.5 20 Zosterella dubia 10 10

Appendix B – Percent Cover Data B-1

Tributary Survey Transect Data 16-Sep-05 Site: T-2 Glenburnie Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 Eleocharis acicularis 2.5 Eriocaulon aquaticum 2.5 2.5 Juncus 2.5 Myriophyllum tenellum 2.5 2.5 Najas flexilis 2.5 2.5 Potamogeton gramineus 2.5 2.5 Potamogeton pusillus 2.5 2.5 Potamogeton robbinsii 2.5 Potamogeton spirillus 2.5 2.5 Sparganium 2.5 2.5 Utricularia resupinata 2.5 2.5 Vallisneria americana 2.5 2.5

Tributary Survey Transect Data 21-Sep-05 Site T-3 Gull Bay Species Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 Elatine minima 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 10 Juncus pelocarpus 2.5 Megalodonta beckii 2.5 2.5 2.5 Myriophyllum alterniflorum 10 Myriophyllum spicatum 2.5 2.5 10 10 Najas flexilis 2.5 2.5 2.5 2.5 Potamogeton amplifolius 10 10 Potamogeton foliosus 2.5 2.5 Potamogeton gramineus 2.5 10 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 2.5 2.5 Potamogeton robbinsii 2.5 10 37.5 Ranunculus longirostris 2.5 2.5 2.5 2.5 Sagittaria cuneata 10 Sagittaria graminea 2.5 Vallisneria americana 20 10 2.5 2.5 Zosterella dubia 2.5 2.5

Appendix B – Percent Cover Data B- 2

Tributary Survey Transect Data 15-Sep-05 Site: T-3A Smith Bay Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 2.5 Juncus pelocarpus 2.5 Megalodonta beckii 2.5 2.5 Myriophyllum spicatum 2.5 2.5 2.5 Myriophyllum tenellum 2.5 Najas flexilis 2.5 2.5 2.5 2.5 Potamogeton amplifolius 2.5 2.5 10 Potamogeton foliosus 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 2.5 Potamogeton robbinsii 2.5 2.5 10 Potamogeton spirillus 2.5 2.5 2.5 Potamogeton zosterella 2.5 2.5 2.5 Ranunculus longirostris 2.5 2.5 2.5 2.5 Ranunculus reptans 2.5 Sagittaria graminea 2.5 2.5 Sparganium 2.5 2.5 Subularia aquatica Vallisneria americana 2.5 10 10 10 Zosterella dubia 2.5 2.5 2.5

Tributary Survey Transect Data 15-Sep-05 Site: T-4 South Burnt Point Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 Elatine minima 2.5 2.5 Elodea 2.5 Eriocaulon aquaticum 2.5 2.5 2.5 Isoetes echinospora 2.5 2.5 2.5 Juncus 2.5 2.5 Lobelia 2.5 Myriophyllum tenellum 2.5 Najas flexilis 2.5 2.5 2.5 Potamogeton amplifolius 2.5

Appendix B – Percent Cover Data B- 3

Potamogeton gramineus 2.5 2.5 2.5 Sparganium 2.5 Vallisneria americana 2.5 2.5 Zosterella dubia 2.5 Tributary Survey Transect Data 15-Sep-05 Site: T-5 Clark Hollow Brook Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 2.5 2.5 Elodea canadensis 2.5 10 10 10 2.5 2.5 Megalodonta beckii 2.5 2.5 2.5 Myriophyllum spicatum 2.5 2.5 2.5 2.5 2.5 Myriophyllum tenellum 2.5 2.5 Najas flexilis 2.5 2.5 2.5 Potamogeton amplifolius 2.5 10 10 10 Potamogeton gramineus 2.5 10 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 2.5 Potamogeton praelongus 2.5 Potamogeton robbinsii 2.5 2.5 2.5 20 37.5 Potamogeton zosteriformis 2.5 Ranunculus longirostris 2.5 2.5 2.5 2.5 Sagittaria graminea 2.5 10 2.5 Sparganium 2.5 2.5 Vallisneria americana 10 10 20 2.5 2.5 Zosterella dubia 2.5 2.5 2.5

Tributary Survey Transect Data 15-Sep-05 Site: T-6 Lamb Shanty Bay Brook Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 2.5 10 2.5 Elatine minima 2.5 2.5 Eriocaulon aquaticum 2.5 2.5 Isoetes echinospora 2.5 2.5 2.5 Isoetes lacustris 10 37.5 2.5 Juncus pelocarpus 2.5 Lobelia dortmanna 2.5 2.5 Myriophyllum spicatum 2.5 Myriophyllum tenellum 2.5 2.5 2.5 Najas flexilis 2.5 10 10 2.5 Potamogeton amplifolius 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 Potamogeton praelongus 2.5 Potamogeton pusillus 2.5 2.5 2.5 2.5 2.5 Appendix B – Percent Cover Data B- 4

Potamogeton robbinsii 2.5 2.5 2.5 2.5 Potamogeton vaseyii 2.5 2.5 Sparganium 2.5 2.5 Utricularia resupinata 10 2.5 Vallisneria americana 2.5 10 10 Zosterella dubia 2.5 2.5 Tributary Survey Transect Data 15-Sep-05 Site: T-7 Brook N. Green Point Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 2.5 10 Elatine minima 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 10 10 2.5 Isoetes echinospora 2.5 2.5 2.5 2.5 Juncus pelocarpus 2.5 2.5 Lobelia dortmanna 2.5 2.5 Myriophyllum tenellum 2.5 2.5 2.5 Najas flexilis 2.5 2.5 2.5 10 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 Potamogeton robbinsii 2.5 2.5 2.5 10 10 Ranunculus reptans 2.5 2.5 Sagittaria graminea 2.5 Sparganium 2.5 2.5 Vallisneria americana 2.5 10 2.5

Tributary Survey Transect Data 27-Jul-05 Site: T-8 Bluff Head Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella 2.5 Eleocharis acicularis 2.5 Elodea canadensis 2.5 Eriocaulon aquaticum 2.5 Isoetes echinospora 2.5 Juncus pelocarpus 2.5 Lobelia dortmanna 2.5 Myriophyllum spicatum 2.5 2.5 Myriophyllum tenellum 2.5 2.5 Najas flexilis 2.5 Nymphaea odorata 2.5 Potamogeton friesii 2.5 Potamogeton gramineus 2.5 2.5 Potamogeton perfoliatus 2.5 Appendix B – Percent Cover Data B- 5

Potamogeton robbinsii 2.5 Potamogeton spirillus 2.5 Potamogeton zosteriformis 2.5 Ranunculus longirostris 2.5 Sagittaria graminea 2.5 Scirpus subterminalis 2.5 Sparganium 2.5 2.5 Vallisneria americana 2.5 2.5 2.5

Tributary Survey Transect Data 7-Jul-05 Site: T-9 Brook by Agnes Island

Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 10 10 10 2.5 Elatine minima 2.5 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 2.5 2.5 Isoetes echinospora 2.5 2.5 10 2.5 Juncus pelocarpus 2.5 2.5 Myriophyllum tenellum 2.5 2.5 10 Najas flexilis 2.5 2.5 2.5 2.5 10 2.5 Potamogeton amplifolius 2.5 10 10 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 Potamogeton robbinsii 2.5 10 10 10 Potamogeton spirillus 2.5 2.5 Potamogeton vaseyi 2.5 2.5 2.5 Potamogeton zosterella 2.5 2.5 Ranunculus longirostris 2.5 2.5 Ranunculus reptans 2.5 2.5 Sagittaria graminea 2.5 10 Sparganium 2.5 2.5 Vallisneria americana 2.5 2.5 2.5 2.5 Zosterella dubia 2.5 2.5

Appendix B – Percent Cover Data B- 6

Appendix B – Percent Cover Data B- 7

Tributary Survey Transect Data 15-Sep-05 Site: T-10 Sunset Bay Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 Elatine minima 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 2.5 2.5 Juncus pelocarpus 2.5 2.5 Myriophyllum alterniflora 2.5 Myriophyllum spicatum 2.5 2.5 20 10 Myriophyllum tenellum 2.5 2.5 Potamogeton amplifolius 10 10 Potamogeton epihydrus 2.5 Potamogeton foliosus 2.5 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton praelongus 2.5 2.5 Potamogeton robbinsii 2.5 2.5 10 20 Potamogeton spirillus 2.5 Potamogeton zosteriformis 2.5 2.5 2.5 2.5 Ranunculus longirostris 2.5 2.5 2.5 Ranunculus reptans 2.5 2.5 Sagittaria graminea 2.5 2.5 Vallisneria americana 10 2.5 37.5 20 Zosterella dubia 2.5 2.5 2.5 2.5

Appendix B – Percent Cover Data B- 8

Tributary Survey Transect Data 7-Jul-05 Site: T-10a Rock Dunder Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 10 10 2.5 Elatine minima 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 10 Eriocaulon aquaticum 10 10 2.5 Isoetes echinospora 2.5 2.5 10 2.5 Juncus pelocarpus 2.5 2.5 Lobelia dortmanna 2.5 2.5 Myriophyllum tenellum 2.5 2.5 Najas flexilis 2.5 2.5 Potamogeton amplifolius 2.5 10 10 Potamogeton gramineus 2.5 10 10 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 Potamogeton robbinsii 2.5 2.5 10 10 Potamogeton vaseyii 2.5 2.5 Potamogeton zosteriformis 2.5 Sparganium 2.5 2.5 Utricularia resupinata 2.5 2.5 Vallisneria americana 2.5 2.5 10 2.5

Appendix B – Percent Cover Data B- 9

Tributary Survey Transect Data 27-Jul-05 Site: T-11 Cook Bay - Hulett's Landing Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella 10 10 10 Eleocharis acicularis 2.5 2.5 Elodea canadensis 10 2.5 2.5 Eriocaulon aquaticum 2.5 10 10 Isoetes echinospora 2.5 2.5 2.5 Juncus pelocarpus 2.5 2.5 2.5 Megalodonta beckii 2.5 Myriophyllum tenellum 2.5 2.5 2.5 Najas flexilis 2.5 10 10 Potamogeton friesii 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 Potamogeton robbinsii 2.5 2.5 10 Potamogeton spirillus 2.5 2.5 Potamogeton vaseyii 2.5 Ranunculus longirostris 2.5 2.5 Ranunculus reptans 10 10 Sparganium sp. 2.5 2.5 Utricularia resupinata 10 20 Vallisneria americana 10 2.5 2.5 Zosterella dubia 2.5 2.5

Appendix B – Percent Cover Data B- 10

Tributary Survey Transect Data 27-Jul-05 Eichlervill Site: T-11 N e Depth Interval (m) Species 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 10 10 10 10 10 Elatine minima 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 2.5 Isoetes echinospora 2.5 2.5 10 2.5 Juncus pelocarpus 2.5 10 Lobelia dortmanna 2.5 2.5 Myriophyllum spicatum 2.5 2.5 2.5 10 75 Myriophyllum tenellum 10 10 2.5 Najas flexilis 2.5 10 10 10 10 Potamogeton amplifolius 2.5 10 20 2.5 Potamogeton gramineus 2.5 2.5 10 10 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton spirillus 2.5 2.5 2.5 2.5 Potamogeton vaseyii 2.5 2.5 2.5 2.5 Ranunculus reptans 10 2.5 Sagittaria cuneata 2.5 2.5 Sagittaria graminea 10 2.5 2.5 Sparganium sp. 2.5 2.5 Utricularia resupinata 2.5 10 Vallisneria americana 10 2.5 10 20 10 Zosterella dubia 2.5 2.5 2.5

Appendix B – Percent Cover Data B- 11

Tributary Survey Transect Data 27-Jul-05 Site: T-11 S Kitchal Bay Species Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 10 10 10 10 Elatine minima 2.5 2.5 Eleocharis acicularis 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 10 10 2.5 Isoetes echinospora 2.5 2.5 2.5 Juncus pelocarpus 2.5 10 2.5 Myriophyllum tenellum 2.5 Najas flexilis 2.5 2.5 10 10 Potamogeton amplifolius 2.5 2.5 2.5 2.5 Potamogeton friesii 2.5 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 Potamogeton perfoliatus 2.5 2.5 2.5 2.5 Potamogeton robbinsii 2.5 2.5 2.5 Ranunculus longirostris 2.5 Ranunculus reptans 2.5 2.5 Subularia aquatica 2.5 2.5 Utricularia resupinata 10 2.5 Vallisneria americana 2.5 2.5 10 10 Zosterella dubia 2.5 2.5

Tributary Survey Transect Data 5-Aug-05 Site: T-71 South trib West of Halfway Island Species Depth Interval (m) 0-1 1-2 2-3 3-4 4-5 5-6 6-7

Chara/Nitella sp. 2.5 2.5 2.5 2.5 10 10 Elatine minima 2.5 2.5 Elodea canadensis 2.5 2.5 2.5 2.5 2.5 2.5 Eriocaulon aquaticum 2.5 20 10 2.5 Isoetes echinospora 2.5 2.5 2.5 2.5 Lobelia dortmanna 2.5 2.5 2.5 Myriophyllum tenellum 2.5 10 2.5 Najas flexilis 2.5 10 20 10 10 Potamogeton amplifolius 2.5 2.5 10 Potamogeton foliosus 2.5 2.5 Potamogeton gramineus 2.5 2.5 2.5 2.5 2.5 Potamogeton pusillus 2.5 2.5 2.5 2.5 Potamogeton robbinsii 2.5 10 10 10 Ranunculus longirostris 2.5 2.5 Appendix B – Percent Cover Data B- 12

Sparganium 2.5 2.5 2.5 Subularia aquatica 2.5 2.5 Utricularia resupinata 2.5 10 2.5 Vallisneria americana 2.5 2.5 2.5 10 10 10

Tributary Survey Transect Data 5-Aug-05 Site: T-72 North trib West of Halfway Island