Aquatic vegetation can be beneficial when the right species in the right abundance are present. Some benefits of aquatic vegetation are erosion control, improved water quality, cover and food for many wildlife species. When an impoundment lacks aquatic vegetation, it could be helpful to establish or promote it. However, not all aquatic vegetation is desirable. Some species, such as Eurasian water milfoil, can become overabundant and out-compete beneficial plants. It is important to manage for plants that help accomplish the goals set for an impoundment.
To determine the species of plants to establish or promote, first determine the purpose of the plants. If the purpose of vegetation is to provide erosion control, then select a moist soil or emergent plant. If the purpose of vegetation is to provide food for waterfowl, then a submerged or floating plant might be more suitable. Two good plants to establish or promote are spike sedge and long-leaf pondweed. There are many different species of spike sedge, but all are limited to depths less than 18 inches. Most are less than 30 inches tall, and the seeds and rhizomes are eaten by waterfowl. Spike sedge provides excellent erosion control and is a great buffer for runoff. Long-leaf pondweed provides good habitat for fish and invertebrates, the seeds are eaten by waterfowl, and it typically does not grow in water deeper than 5 feet in ponds.
Long-leaf pondweed is an excellent aquatic plant for fish and wildlife.
There are several ways to establish aquatic vegetation such as spreading seed or transplanting individual plants, which are both commercially available or can be easily collected. If the plant is rooted, dig plugs about softball sized and plant them at the same depth where they originated. If the vegetation is not rooted, simply transplanting from one impoundment to another might be enough for establishment because many aquatic plants propagate from fragments. However, caution must be taken to avoid accidental introduction of non-desirable species. Since many plants spread by seed and fragments, it is hard to transplant without introducing a non-desirable plant if it exists in the source location. Many plants are limited by depth, so slope must also be considered when selecting species and site.
For some species to become established, fencing from cattle and turtles is commonly needed. Fencing an area or whole impoundment from cattle will prevent grazing and trampling, allowing vegetation to establish and spread. Excluding turtles requires fencing such as construction barrier fencing that is tall enough to extend above the surface of the water when full. Construct small exclosures (3 to 5 feet in diameter) close to each other so vegetation can grow together to create a "critical mass" that turtles will be unable to keep up with.
Establishing aquatic vegetation allows managers to select the species they want in an impoundment instead of waiting for nature to take its course. Selecting desirable species can help managers achieve their water quality and wildlife goals.