Early summer lake users noticed an increasing distribution and density of weeds in much of East and No Fish bays in the years leading up to 2002. The weed masses, many of which formed dense surface mats, would disappear by mid-summer. It was not until the spring of 2002 that the offensive plants were identified by DNR personnel as Curly-leaf pondweed (Potamogeton crispus), a non-native species capable of causing harm to lakes and navigational obstructions to boaters.
The lake district board of commissioners sprang into action when learning that an invasive species had arrived in Little Saint. An initial response plan was formulated during the following months and implemented in May of 2003, just as more bad news arrived. A fragment of Eurasian watermilfoil (Myriophyllum spicatum), another non-native and potentially harmful plant, had been found floating in West Bay. An immediate search was initiated to determine if the floating fragment had come off a boat or trailer that had transported it in from another lake or if a colony of plants had become established. Extensive SCUBA diving efforts revealed a large patch growing near the public boat landing with several more smaller colonies scattered around the perimeter of West bay.
While both Curly-leaf pondweed (CLP) and Eurasian watermilfoil (EWM) had been nuisance plants in other parts of the U.S. and in southern areas of WI for many years, neither had been dealt with sufficiently to provide a road map for how to proceed with managing either species in northern WI lakes. The DNR required permits for most methods of aggressive management, but could not provide assurance that any of the available control methods would provide long lasting relief.
Part time lake resident John Manki stepped up in 2003 and wrote a five year management plan for both CLP and EWM. The plan employed aquatic herbicides, the best know method of control at the time. The plan was reviewed by the Rhinelander office of the DNR, modifications were made as requested, and the plan was approved. Professional chemical applicators were to be used and lake volunteers would provide annual monitoring for effectiveness of the herbicides as well as watching for new growth within or beyond treatment sites. The Vilas County Land & Water Conservation Department provided assistance in developing effective monitoring procedures.
John Manki also prepared a DNR grant application seeking State financial assistance for the cost to implement the plan. The price tag to manage the two invasive plant species was estimated at $240,000 for the first five years. The DNR agreed to pay $120,000 with the balance to be paid from whatever sources the lake district could tap. The plan was implemented in May of 2004. At the conclusion of 2007, costs had totalled nearly $190,000.
The characteristics of CLP makes it releatively easy to control compared to EWM, although every bit as costly. Following the first chemical application in 2003, the high density plant mats disappeared. An uninformed observer might conclude that the CLP had been successfully eradicated. In truth, it is only because of the dedication of volunteers who understnad the growth cycle of the species and continued annual aggressive management that CLP seems to be gone. It is actually still present in the lake, although in far lower densities, and likely will be until a method to achieve true eradication is developed.
EWM has proven to be extremely difficult to control. Managing it can be compared to patching an old hose. No matter how many places are fixed, new leaks keep developing. It has spread to every bay of the lake since first being found in West bay in 2003. The initial objective of John Manki's five year management plan was to reduce the infestation to a level where ongoing management could be afforded without DNR funding. At the close of 2007, with only one year remaining in the five year plan, it is apparent that the goal will not be achieved. This less than optimal result should not, however, be regarded as failure. EWM is being managed successfully enough that most lake users will not knowlingly encounter it. As opposed to lakes where EWM beds restrict boat navigation and interfere with fish habitat, the infestation in Little Saint is being maintained below nuisance levels.
Much was learned during the initial four years of attempting to manage these species. The management plan has been reviewed and modified annually as the Board of Commissioners, the dedicated team of volunteers, and the DNR have learned what works and what doesn't. A professional lake management consultant (Onterra, LLC of DePere, WI) became part of the management team early in the process. Onterra will assist in the development of a new and revised long term management plan for both EWM and CLP during 2008 for implementation in 2009 and beyond. Additional grant funding will also be sought for implementation of the ongoing plan.
More information about both CLP and EWM and management efforts on Little St. Germain Lake can be accessed by clicking on the following links:
NOTE: PROPOSED treatment sites are based on survey work accomplished during the previous summer and fall. The maps reflect what are likely to be the actual sites to be treated with herbicides the following spring, but all sites will be verified by a professional lake management consultant prior to the final chemical application permit being issued to the chemical contractor.