Adirondack Ecologists, LLC Crown Point, New York

Transcription

1 2013 Paradox Lake Invasive Species Management Annual Report Paradox Lake (Essex County), New York prepared by Adirondack Ecologists, LLC Crown Point, New York

2 I. Background Information: Eurasian water milfoil (Myriophyllum spicatum),hereafter referred to as milfoil or EWM, was first discovered in Paradox Lake by Steve LaMere of Adirondack Ecologists, LLC (AE) on September 2,2008, during a routine reconnaissance inspection performed by the Crown Pointbased lake management company. This initial sighting took place near the boat launch ramp at the New York State Department of Environmental Conservation campsite on Paradox Lake, and it precipitated in the discovery of a second infestation situated in the bay just northwest of this site. This bay is a site where campers have traditionally moored their boats while utilizing the campground, and for decades it also served as the campground's bathing beach. AE responded rapidly and hand harvested a total of 51 milfoil plants near the boat launch ramp on September 7 and an additional 508 milfoil plants were harvested from the bay near the beach area on October 17. These discoveries resulted in the development of a milfoil management program for Paradox Lake. This management program was developed by AE, in conjunction with the Paradox Lake Association,Inc. (PLA), and the Town of Schroon, and it was instituted in The primary focus of the program was to control the growth and expansion of milfoil in order to foster the environmental, aesthetic, and recreational values of the lake. The program contained two basic parts - a surueillance (monitoring) component and an eradication (control) component. The objective of the monitorins component was to find milfoil and any other invasive species wherever they might exist in the lake. In order to accomplish this objective, AE recommended the performance of a series of annual inspections of the near-shore littoral zone of the lake by a professional experienced in providing this type of service. During this survey process, the littoral zone is traveled in a zigzag fashion via boat and this region of the lake is inspected out to a water depth of roughly 8+ feet (water transparencypermitting). This survey method is an excellent way of locating "beds" of mature milfoil plants, and it sometimes can even be successfully used to help identify scattered or individual plants. Normally, however, more extensive and expensive survey techniques, such as SCUBA surveys, are warranted when searching for small-scale, sparsely-established infestations. Along with monitoring, an education program was initiated, and on May 24, Steve LaMere, Tyler Smith of The Nature Conservancy, and Gretchen Sunderland and Tom Jurek of the PLA collaborated to hold a training and education workshop for the membership of the lake association to help foster an improved understanding of milfoil, its ecology and identification.

3 In addition, AE recommended that a milfoil "scout" program be implemented by the pla, in order to help provide continual reconnaissance for potential invasive species introductions into the lake. In June, the newly-trained scouts commenced their activity and the entire shoreline of the eastern basin was both boat- and kayak-surveyed by volunteer scouts, while AE performed, multiple lake-wide inspections via boat. A snorkel survey of the entire southern shoreline from the mouth of the nalrows to the far eastern end of Site 10 (see map) was also performed by AE during the summer. By the end of the 2009 field season, the cooperative surveillance program had been responsible for the identification and documentation of seven new milfoil infestations in the lake. A11 of these additional sightings were located in the eastern basin, and all but one consisted of individual or scattered plants at various locations around the lake. AE id,entifred a more extensive patch of milfoil situated in the bay at the far eastern end of the lake near the inlet, and this site could have potentially caused significant long-term problems if left undiscovered and untreated. In addition,ae discovered a second invasive species during the summer of Roughly 18 curly-leaf pondweed (Potamogeton crispis) plants were identified in Legoys Bay and a few scattered P. crispis plants were also documented near the beach site. Laterln the season, Gretchen Sunderland discovered a relatively small-scale, but concentrated curly-leaf pondweed infestation just west of Grass Island in an area commonly utilized by local and visiting fishermen. Curly-leaf pondweed, hereafter referred to as CLP, is a submersed species that spreads by both turion production and fragmentation. It generally becomes problematic earliei in the growing season than milfoil does, but diminishes by August in northem climes. It can be effectively controlled if discovered early and control is implemented prior to turion detachment. The objective of the control component of the program is simple: to eliminate in as timely a manner as possible any invasive, aquatic plants that are discovered. Given the nature of the infestation present in Paradox Lake, this objective can best be accomplished via selective hand harvesting, It is clearly the most cost-effective and environmentally-ssrri,ive approach to control available. One of the prime considerations of hand harvesting milfoil is the amount of bottom detritus or silt that is stirred up during the harvesting process. The more flocculent the lake sediment is or the more clay that is present in the sediment, the more material that is distributed into the water column during harvesting. This material, once disturbed, minimizes visibility and occasionally eliminates it completely for a certain period of time, thus requiring that diveri move to an adjacent site or a completely different infestation until the visibility clears up. _) _

4 II. Control Activity Summaries: 2009 A total of 705 milfoil and 116 curly-leaf pondweed plants were harvested during the 2009 control season, and the focus of 2010 efforts shifted somewhat to include a greater effort on locating and controlling areas of curly-leaf pondweed infestation in the lake. The discovery of this invasive species the previous year highlighted the importance of scouring the littoral zone for other potential areas of infestation. Scouts started inspecting the shoreline in late May with several volunteers identifying new locations possessing curly-leaf pondweed. An education forum was offered once again over the Memorial Day weekend, and a new "lake steward" program was initiated during the summer at the state campsite boat launch site. Employees of the Southwoods Camp and PLA volunteers manned a check station just a few hundred feet above the launch site in order to check incoming boats and trailers for invasive species and to help educate boaters on the importance of invasive species prevention. On one occasion, a boat with zebra mussels attached to it was caught by volunteers before it was launched, and these invasive organisms were removed from the watercraft before entering the lake Harvesting commenced on June 10 and the control season officially ended on September 3. A total of 993 milfoil and 1,879 curly-leaf pondweed plants were removed from Paradox Lake during the late spring and summer of A total of thirteen partialifull days were spentby AE in control efforts in the east basin and roughly six partial/full days were spent performing reconnaissance inspections of the littoral zone in both basins. During the summer of 2010, AE discovered milfoil growing in relatively deep (9 to 11-foot) water in the far eastern bay of the lake and also just off of the western tip of Grass Island. Some of these plants were quite long and lush. Volunteers discovered new, relatively small milfoil infestations on the southern side of Crawford Island and along the southern shoreline of the lake east of that island. In addition, new curly-leaf pondweed infestations were found along the southern shoreline of the east basin in the vicinity of both the Granger property and the Bruce property. To date, the most extensive infestation of milfoil found in the east basin is situated in the bay near the main inlet to the lake, and the most extensive curly-leaf infestation is spread out along the shoreline of Legoys Bay. -3-

5 A new species of aquatic plant not previously identified in Paradox Lake was documented by AE during the fall of This species, Megalodonta beckii, used to be on the New York State Rare Plant List, but due to additional sightings in multiple lakes it was upgraded to the NYS Watch List. 201 I Roughly 14 harvesting, 5 reconnaissance and 1.5 education/training days were spentby AE during the field season. In addition, PLA volunteers (launch ramp stewards and scouts) spent a total of 503 hours assisting with education and monitoring. Harvesting activities started June 15 and ended September 27. Two new small areas of EWM infestation were discovered, one in Dark Bay and one along the northern shore just east of Legoys Bay. A new CLP location was also documented along the northern shoreline near the'onarrows" (now designated Site # 13b.). Inlet Bay (the bay situated at the far eastem end ofthe lake) for the second year in a row possessed the highest concentration of milfoil in the lake, and the shoreline in and adjacent to Legoys Bay possessed the highest concentration of CLP. The littoral zone just west of Grass Island also consistently yielded sightings of both CLP and EWM. The launch ramp steward program was responsible for discovering EWM on one incoming boat and water chestnut (Trapa notans) on another. Many lakeshore property owners assisted with this undertaking by volunteering their time, and in addition, The Southwoods Camp, a private retreat for children situated in the watershed of Paradox Lake, paid two staff members to assist with launch ramp monitoring activities during the summers of 2010 andz}ll. A total of 27 1 EWM and 67 4 CLP plants were taken out of Paradox Lake in 201I. This represents an overall 72.7 % and 64.1oZ decrease in the number of EWM and CLP plants harvested, respectively, from 2010 to Clearly, the battle to control aquatic invasive plants in this body of water is being steadily won over time in those locations that we are aware of and are actively managing Roughly 15 partial days over a 3-month period were spent hand harvesting EWM and CLP in Control efforts commenced on May 25 and ended on August 25. In2012, the PLA and AE undertook an intensive effort to survey a much larger percentage of the lake's littoral zone than had been accomplished in the past. The primary reason for this was -4-

6 because the Town of Schroon was involved in a dam replacement/repair project on the outlet of Paradox Lake and the water level of the lake itself was much lower than it had been in many years, thus offering a perfect opportunity to check in areas where water depths normally exceeded feet. In addition, more emphasis on volunteer shoreline/scuba surveys and professional SCUBA surveys was placed on the priority list of 2012 tasks. Because of this intensive effort, entire bays were surveyed in some cases and these surveys yielded the discovery of additional plants in deeper sections of the lake. Basically, the focus of the control program shifted from maintenance-mode hand harvesting in shallower areas (less than l0 feet of water) to an aggressive reconaissance for new plants in deeper areas (more than l0 feet of water) of the lake. Inlet Bay (the bay farthest east in the eastern basin) had the highest number of EWM plants harvested while Legoys Bay had the highest number of CLP plants. Deep water SCUBA surveys by AE picked up additional EWM plants around the periphery of Grass Island and intensive volunteer surveys in The Narrows and along the northern shoreline of the east basin resulted in the discovery of more EWM plants. A total of 3,617 EWM and2,086 CLP plants were harvested from the lake in20l2. Many of the existing (older) beds were found to possess much less EWM than in years past or none at all. The larger bays that received so much recon attention this past summer yielded higher harvesting takes, which obviously resulted in an increase in the overall number of plants removed from the lake for the control season. By the end of the field season, however, in-lake surveys were not picking up any unharvested milfoil plants. Annual monitoring performed by AE indicates that there has been no perceivable change in the character or composition of the Paradox Lake aquatic plant community at any of the management sites since the inception of the harvesting program. It is the intention of both AE andthe PLA to continue with routine monitoring and management of CLP and EWM on an annual basis in Paradox Lake in order to maintain control over these populations. In addition, an invasive species management plan is being written by AE to address the prevention and management of invasive aquatic species in the lake, and this plan will be incorporated into a larger, more holistic lake management plan (LaMP), which will also be drafted by AE over the next few years. A third nuisance aquatic plant species, variable-leaf milfoil (VLM), was documented by AE in Paradox Lake during the summer of This suspect species was actually first sighted by AE toward the end of the 2012 freld season growing adjacent to Grass Island. By July of 2013, it -5-

7 appeared that both the quantity and density of this milfoil species had increased and samples were subsequently collected for identification using a dichotomous key.,4,e' positively identified it as VLM and had two other authorities, Lawrence Eichler of the Darrin Fresh Water Institute (DFWI) and Scott Kishbaugh of the New York State Department of Environmental Conservation (NYSDEq confirm its ID. Additional reconnaissance performedby AE and PLA volunteers indicated that several other locations around the lake, including Inlet Bay, possessed populations of VLM. There is some disagreement in the scientific community as to whether VLM is an invasive species or not. Historical data clearly indicates that VLM populations have existed in lakes in central New York since the 1800's. However, it has been argued that perhaps genetically-different strains of VLM have developed over time or have been introduced from other areas and that these strains should be considered "invasive". The important thing is not necessarily how VLM is classified, but how it behaves under natural conditions in Adirondack lakes. Certainly, in some northern lakes this plant has grown to nuisance proportions and has become problematic in relatively shallow areas. A total of eleven partial days were spent on the lake harvesting three nuisance aquatic plant species. Harvesting activities started on July 1 and ended on September 7 anda total of 2,879 EWM, 277 CLP and 1,300 VLM plants were removed from the lake. The total take was a result of harvesting efforts by AE and several volunteer divers/snorkelers/waders, including Emery Dergosits, Jim Clarke, Doug Hamilton, Dave Gregory, Gretchen Sunderland, Jim Frederick and others. Please refer to the 2013 Paradox Lake Invasive Species Monagement Activity Zog located in the appendix section of this report for a general description of the control activities at each site. In addition, amap has been included which provides a pictorial illustration of the milfoil and curly-leaf pondweed sites currently identifi ed. Plans for 2014 include a broader effort on identifying and harvesting new areas of VLM infestation and continuing with maintenance control efforts on EWM and CLP. -6-

8 APPENDIX

9 2OL3 Paradox Lake lnvasive Species Management Activity Log Site #1 (state campsite launch ramp area) Site #2 (state campsite beach area) 25 EWM * 14 EWM * Site #3 (Peaked Hilltrailhead) August 12 2 EWM 383 EWM * Site #4 (Biscuit Rock Bay) 4EWM* Site #5 (Legoys Bay) Site #5a (near Bonnie Pont) August EWM 87 EWM * 11EWM * Site #6 (Grass lsland) July 1& 27; September EWM 391EWM * July 1 & 27; September CLP September 7 8OO VLM 5OO VLM Site #7 (Glen Raey Cove) 50 EWM * Site #8 (lnlet Bay) July 21 & 22; August 5, 5 & EWM 507 EWM * Site #9 (southern point across from Crawford ls.) 2EWM* Site #10 (southern shoreline across from Birch ts.) Site #11 (near Granger's) Site #12 (off of small rock point) None Found 5EWM* 22 EWM X

10 Site #13a (mouth of Narrows - south shore) August EWM 93 EWM * Site #13b (mouth of Narrows - north shore) 6EWM* Site #14 (south side of Crawford tsland) None Found Site #15 (southern shoreline west of lnlet Bay) Site #16 (Coldwell's Bay) Site #17 (Crawford's Cove) Site #19 August 11 None Found 20 EWM * 5EWM * 30 EWM * Site #20 (Sunderland Bay) None Found Site #21 (Birch lsland) None Found TOTAL # of Eurasian water milfoi! plants 2,879 TOTAL # of curly-leaf pondweed plants 277 Total # of variable-leaf milfoil plants 1,300 * = plants harvested by volunteers

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