2012-02-16_AgendaPacket - Laserfiche WebLink

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tLake Vegetation Management Plan Appendix 1: Background Information. Rationale for Section II: Water quality and plant community Values of Aquatic Plants in Lakes Aquatic plants are valuable for a number of ecological and biological functions including utilizing nutrients that would otherwise be available to algae, stabilizing bottom sediments and shorelines, providing shelter for a variety of game and non -game fish and aquatic insects, and providing food for waterfowl and other wading birds. There is evidence that removal of submersed aquatic plant through the use of herbicide can harm lakes (such as reductions in populations of vegetation- dependent fish, removal of nursery habitat for fish, removal of habitat for invertebrates (food source for waterfowl and fish), and reductions in water quality). Cumulative loss of aquatic plants (especially when coupled with nutrient loading) can lead to drastic ecological changes in lakes causing the lake to have low water clarity, become algae dominated with little to no rooted aquatic plants, and shift to disturbance - tolerant fish species such as bullhead and carp (Engle 1990; Wilcox and Meeker 1992; Scheffer and Carpenter 2003; Egertson and Downing 2004). Section VI: Treatment plan Target Concentration: Current recommended rates for selective CLP treatment utilize Endothall applied at a rate to achieve a target concentration of 0.75 -1.0 ppm up to 1.5 ppm for areas less than 1 acre. For 2012, the selective treatment of EWM uses Auxin Mimics applied at rates to achieve target concentrations of up to 1.0 ppm bay wide. Selective control of invasive species is an evolving science and the treatment protocol may change as new information becomes available. Timing of Application: Timing of bay wide application for Curly leaf pondweed will be early spring when invasive plants are actively rowing but before the majority of the native plants be On n to germinate before 60 degrees F� to reduce the damage to native plant and to prevent turion development. Timing for Eurasian Watermilfoil treatments will be according to product label directions. Frequency of Treatments: If the mean number of native species per point decreases during the first year of lake wide treatment, it is expected that lake -wide treatments will not be done during at least the first year after lake -wide treatment until native species per point reach pretreatment levels in order to meet Goal 3. Lake -wide treatments may be repeated at intervals of every other to every third year, depending on trends in the frequencies of the target invasive plants and also non - target native plants. If the mean number of native species per point does not decrease during the first year of lake - wide treatment, then lake -wide treatments may be considered during the following year. Narrative: One of the situations the DNR considers issuing a variance to the 15% limit is for the selective control of invasive species for ecological and recreational benefit. Currently, invasive species do make up a significant proportion of the plant community and are an ecological or recreational nuisance. Applying herbicides in early spring can potentially increase their selectivity by targeting CLP and EWM at a time Lake Owasso LVMP 11