Plants are an important part of our environment. They provide us with food, building products, medicine, shade and beauty. Aquatic environments rely on plants as much as we do to remain healthy and vibrant. Just like on land though, aquatic plants can grow in areas or ways that impede the use and enjoyment of our resources. Exotic (non-native) plants can even be detrimental to the ecology of a water body. How we balance human interests with the ecological needs of the lakes and streams will determine the long-term health and usefulness of our waterways. The two questions that are frequently asked of lake managers are: “Why don’t you just kill all the weeds in the lake?” and “Why don’t you stop poisoning the lake and let nature take its course?” These two questions point up the competing interests of lake users, and the difficulty in developing a management plan that satisfies all parties.
Aquatic plants provide food and shelter for a wide range of aquatic organisms.They also protect water quality by producing oxygen and absorbing nutrients from the water column.Emergent plants that grow along the shoreline and shallows of a lake provide essential erosion control that can save our valuable lakefront land, and reduce turbidity in the lake.These plants also provide feeding areas for many native bird species.For these reasons, killing all the plants in a lake is unwise.We would end up with poor fish and wildlife populations, frequent and severe algae blooms (rapid, massive growths of algae due to excessive nutrients) and eroded banks.
Although vegetation in general is good for a lake, we also cannot leave nature to run its own course in urban lakes.There are two main reasons for this.First, a number of non-native aquatic plants have been introduced to Florida.These plants have no natural enemies here, and grow out of control if left alone.Plants like hydrilla (Hydrilla verticillata) and water hyacinth (Eichornia crassipes) can completely cover the surface of a lake, preventing any recreational uses.When infestations reach this level, the plants also can cause massive fish kills due to oxygen depletion (caused by decaying plant material, and the isolation of the lake from the light and air above).Second, large inputs of nutrients from stormwater runoff (which carries sediment, leaves and fertilizers) have enriched our lakes to the point that even native plant species can grow out of control.Plants like cattail (Typha spp.)or even pickerelweed (Pontederia cordata) can form dense monocultures that reduce wildlife diversity and create huge muck deposits in shallow areas of the lake.An effective plant management program is needed to prevent rapid degradation of our lakes.
In order to meet the challenges of maintaining beneficial plants while minimizing undesirable ones, the city has developed an integrated management program that includes chemical, biological and mechanical control methods.This program is augmented by a public education program and a regulatory framework that covers shoreline vegetation removal activities. Each of these segments of the plant management program is discussed in detail by accessing the tabs to the left.