Water lilies are known for their beauty and for adding aesthetic value to ponds and lakes. Fish and other aquatic life use the lily pads as shelter from both the sun and predators, and water lilies can become an important part of an aquatic ecosystem. However, too much of a good thing is possible; an overgrowth of water lilies can have dangerous consequences for other lake organisms.
If the lily pad population grows to cover more than 35 per cent of the water surface, the food supply for fish in the lake quickly begins to suffer. Many fish feed off insects that skim the water's surface. If lily pads cover such a large percentage of that surface, food availability goes into a sharp decline. Water lilies can also prevent any plants that are growing underwater from receiving the sunlight they need for photosynthesis. As a result, the entire food chain of the lake can be quickly disrupted.
Water lilies are not free-floating plants and are actually connected to the ground below by a long root that extends up to the lily pad. As a result, an overgrowth of water lilies can make lake recreational activities difficult. Lilies can easily get entangled with fishing lines and can also ensnare the propeller of a boat motor and cause damage to its engine.
An ecosystem functions best when there is a balance between the plants and animals in existence within that ecosystem. If water lilies grow out of control and disrupt the food chain of the ecosystem, species will start to die off due to a lack of available nutrients. Much like a virus overruns an immune system until the virus dies, water lilies continue populating a lake until little else survives in it, since all the available resources are taken up and new resources can no longer be generated.