CHAPTER 11 - A Citizen's Manual for Developing Integrated Aquatic Vegetation Management Plans

 SPECIFY CONTROL INTENSITY (STEP I)

This step of the Plan development involves determining how much control is needed for particular plant problems. Are there plant zones around the lake that should be left alone (no control)? Where should a low level of control be applied to preserve some intermediate level of plant growth? And under what circumstances would a high level of control be necessary, such as where a minimal amount of nuisance plants can be tolerated.

What Are The Different Levels Of Control?

No Control: It may be best to leave special habitat areas untouched, such as shoreline wildlife conservancy areas that serve as nesting and forage sites for waterfowl and other animals. Sometimes these sanctuary areas are islands within the water body system. Native plant beds that function as fish spawning sites might best be left alone or subjected to minimal treatment. In some cases, the presence of native plants may have aesthetic value to the surrounding community.

Low Level of Control: Low levels of control might be all that is needed to attain your management goals. This usually involves a partial removal of vegetation. For instance, in lakes where a warm-water fishery is important, using mechanical means to develop fish lanes through vegetation can be quite valuable. Low-intensity control efforts are also important in shoreline treatments where emergent vegetation is to be protected. Low-level control maximizes enjoyment of a water body while minimizing plant removal. A benefit of low-level control using mechanical means is the low treatment cost per acre because less plant material is removed.

High Level of Control: Certain situations may require aggressive control. For safety reasons it may be necessary to clear all vegetation from swimming or wading areas. Other areas requiring intensive removal may include areas around docks or boat ramps. The presence of invasive non-native plants may justify aggressive measures to remove plants. Lake-wide control efforts affecting 100 percent of aquatic plants are not appropriate, except in lakes where invasive, non-native plants have been identified.

How To Determine Levels Of Control In Water Body

To determine appropriate levels of plant control in your water body, refer to: the water body usage map and the aquatic plant map. The following tasks describe how to use these maps to produce a control intensity map.

TIP: If the maps are the same size and scale, they can be overlaid. A blank map of the water body showing just the shoreline outline can be placed over these to produce the control intensity map.

Task 1. On the usage map, identify use areas of the water body that are not impacted by existing aquatic vegetation growth. Make a list of these use areas under the heading NO CONTROL.

Task 2. Next, locate areas around the water body that are or have the potential to be designated conservancy zones or confirmed endangered, rare, or sensitive plant populations. Add these areas to NO CONTROL list, if not already included.

Task 3. On the usage map, identify use areas of the water body that require some control of existing aquatic vegetation growth. Make a list of these use areas under the heading LOW CONTROL.

Task 4. Referring to the aquatic plant map, recheck that low control areas do not contain endangered, rare, or sensitive plant populations. If they do, REMOVE from low control list.

Task 5. On the usage map, identify use areas that require maximal removal of aquatic plant growth. Make a list of these areas under the heading HIGH CONTROL. 

Task 6. Referring to the aquatic plant map, locate areas with invasive, non-native plant populations (like Eurasian watermilfoil or Brazilian Elodea). Include these areas on the list of HIGH CONTROL if not included.

References and Resources on Sensitive Plants

The end product is a map clearly showing zones of all three control intensities (See control intensity map for Lake Tranquil). Construction of a control intensity map will aid in choosing appropriate treatment options for each area of the lake (Chapter 12).

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