In moderation, aquatic plants are good for the lake. They provide habitat and food for fish and other organisms, stabilize bottom sediment, improve water clarity and quality, and can improve the overall aesthetics of the lake. Much of the fishing and recreation industry rely on a balanced, aquatic plant community. Aquatic plants become a problem when they become overabundant and interfere with the use of a lake. A number of factors combined may result in excessive aquatic weed growth. If the plants in your lake are impeding with its use and aesthetics, then there may be a problem.
Plant overgrowth and algae blooms result from a variety of sources. Over several years, a lake will fill up with sediment made up primarily of decayed plant and animal matter as well as eroded soil washed in from land. As the sediment builds up, so does the nutrient bank, making the water more fertile for plant growth. Other attributes to the nutrient build-up include the weather and human activities. Runoff into the lake may contain fertilizers and other nutrient sources such as phosphorus and nitrogen. With addition of all these nutrients, it is very common overtime to see a steady increase in the plant growth on the lake.
Generally, there are two categories of plants in a lake, native and exotic. Both, if overgrown can cause problems, but invasive, exotic species cause the most problems. Exotic species have been brought over, both accidentally and intentionally, from other continents. Because they have very few natural enemies, they grow out of control, eventually stomping out the native plants needed to maintain balance and health of the lake. Invasive, exotic plant growth will likely begin negatively affecting fish, waterfowl, and other aquatic species, by blocking sunlight, increasing nutrients, and inhibiting the food chain of a lake.
Invasive Exotic species present a much greater threat to a lake than that of native vegetation. These are plants that are not native and come from other parts of the world. Exotic plants typically out compete native vegetation once established. They will also grow where native plants do not, such as underneath docks, in flowing water and areas of high traffic. Some exotic plants can grow up to two inches a day. Eradication of exotic plants within a lake is rare. Proper management of exotic plants must be on-going.
Education can keep future costs down by having knowledgeable people make decisions which may result in less professional management activities. Representatives of PLM Lake & Land Management are always available to speak to organizations including lake associations, lake improvement districts, municipalities, schools and individual homeowners, free of charge.
Lake management activities should be performed lake-wide. In order to manage problems successfully PLM Lake & Land Management has developed Best Management Practices for many lakes in the United States. We refer to these as BMP’s.
There are three processes to the Best Management Practices:
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What is an Invasive Plant?
An invasive plant has the ability to thrive and spread aggressively outside its natural range. A naturally aggressive plant may be especially invasive when it is introduced to a new habitat. An invasive species that colonizes a new area may gain an ecological edge since the insects, diseases, and foraging animals that naturally keep its growth in check in its native range are not present in its new habitat.
Some invasive plants are worse than others. Many invasive plants continue to be admired by gardeners who may not be aware of their weedy nature. Others are recognized as weeds but property owners fail to do their part in preventing their spread. Some do not even become invasive until they are neglected for a long time. Invasive plants are not all equally invasive. Some only colonize small areas and do not do so aggressively. Others may spread and come to dominate large areas in just a few years.
Invasive plants disrupt many natural habitats. They are most threatening in ecosystems such as wetlands, sand dunes, fire prone areas, and serpentine barrens where rare native plants are found. Invasive plant species thrive where the continuity of a natural ecosystem is breached and are abundant on disturbed sites like construction areas and road cuts. Even foot traffic can create a temporary void that is quickly invaded–some national parks have restricted the areas where visitors are allowed to walk with the warning, “we can watch purple loosestrife grow from people’s footsteps.”
It’s a matter of ecology. In many cases, plants from other parts of the world are welcomed, manageable additions to our gardens. However, in some situations these non-native species cause serious ecological disturbances. In the worst cases, invasive plants like mile-a-minute, purple loosestrife, and kudzu ruthlessly choke out other plant life. This puts extreme pressure on native plants and animals, and threatened species may succumb to this pressure. Ultimately, invasive plants alter habitats and reduce biodiversity.
In some cases, invasive plants arrive purely by accident, as seed in agricultural products, or on shipments from overseas. In other cases, invasive plants are selected for their horticultural attributes. Beautiful, unusual, exceptionally hardy, drought-tolerant, or fast-growing plants are sought by gardeners the world over. Unfortunately, plants selected for their resilience may be invasive because of their adaptable nature. Plants selected for their aesthetic value may be hard to banish from your garden even after their invasive tendencies are revealed.
Precise application of aquatic herbicides can save time and money. At PLM Lake & Land Management we track our herbicide application patterns and harvesting areas using GPS coordinates to create patterns called application footprints. This information allows the client to verify the proper areas are being managed and monies are being spent efficiently.
Variable rate controllers on board our equipment can precisely distribute product even at extremely low rates. Preloaded “prescriptions” are programmed into an onboard computer. As the equipment travels, speed, location, and the product rate are continuously monitored and recorded. As the parameters change, the rate of application is adjusted. Each application is saved for reference and to ensure that future applications will be done in the exact same manner.
CAD software allows for more precise modeling of lakes. Depth measurements are calculated along with contour data to determine the exact volume of the different layers of a lake. Most products are volume based and require detailed depth profiles of every location used, it is very important to know not only the depths of the areas but the densities of the plants because the plants will account for some of the volume. This information is very important when selecting a product as well as the amount of product to be used.
A bathymetric map is a map that accurately depicts all of the various depths of a water body. Many lakes or ponds do not have a bathymetric map, or may have a very outdated map. An accurate bathymetric map is essential when applying for a permit for herbicide applications through the Department of Environmental Quality. It is also an important tool when deciding which form of management is most appropriate for a water body. Lake volumes, hydrolic retention time and carrying capacity are important parts of lake management that require the use of a bathymetric map.
PLM Lake & Land Management Corp. has the ability and knowledge to accurately map your lake or pond. Through the use of Global Positioning Systems and Global Information Systems a detailed representation of your water body can be charted.
Many herbicide products require a certain amount of contact time to achieve control. Water samples can be collected to determine the concentration of product in the water. These tests are a great way to determine if the target rate and exposure time determined by the plant assays have been achieved. Water monitoring can also determine when treated water can be used for watering lawns and gardens.
Monitoring the effects of the treatments over time can ensure that planned goals are met. The information can be used in future treatments. Sediment samples can be taken to determine the amount and viability of plant seeds and turions. Also, aggressive monitoring of lakes can effectively reduce the population of target plants by rapidly identifying and managing small populations before they become major problems.