By Kevin Lollar • June 1, 2008
This week a team from Florida Gulf Coast University planted 360 shoots of the aquatic grass vallisneria, also known as tape grass and eel grass, in shallow water on the southwest side of the 1,500-acre lake near Immokalee. Over the summer, the team will plant several thousand vallisneria shoots in the lake.
Later this year, the state will plant bulrush in the same area.
“The lake is imperiled,” research associate David Ceilley said. “The EPA and the state have recognized that it needs to be fixed. What we’re trying to do is jump-start restoration of the lake.”
Lake Trafford, a popular fishing spot for Southwest Floridians, including Lee County residents, started going downhill decades ago when its water became choked with the exotic pest plant hydrilla.
As the plant died naturally, it sank to the bottom, rotted and became muck.
Hoping to solve the hydrilla problem, officials sprayed it with herbicides in the 1970s. Tons of dead plant material rotted to increase the muck layer until it was 6 feet thick and smothered the lake’s bottom vegetation.
As muck rots, it depletes the dissolved oxygen in the water. High winds stir up the muck, and trapped nutrients become suspended in the water, sparking algal blooms. The algae suck more oxygen from the water, and fish suffocate – rotting fish also add nutrients and remove oxygen.
Over the past 12 years, the lake has experienced several major fish kills.
In November 2005, a $10.3 million project got under way to remove the equivalent of 30,000 dump-truck loads of muck from the lake. The demucking project is being paid for by Friends of Lake Trafford, the Florida Fish and Wildlife Conservation Commission, Collier County, state monies, and the Big Cypress Basin, which is part of the South Florida Water Management District.
Most of the muck has been removed, but dredging has been temporarily stopped because water levels in the lake are too low for equipment to work.
Removing muck leaves a nice, clean lake bottom, but nice, clean lake bottoms don’t support much life. Muck is gone, plants are going in Plants set in de-mucked lake bottom
To be healthy, a lake needs vegetation, and vallisneria is one of the most important freshwater plants in North America.
Found in many freshwater bodies of the contiguous United States and parts of Mexico and Canada, vallisneria is food for fish, turtles, manatees and birds. It provides habitat for small fish, crabs, shrimp and clams and traps nutrients to help prevent algal blooms.
“We have the opportunity to re-establish native plants that are good for the environment,” said Clarence Tears, director of the Big Cypress Basin, which is putting up $25,000 for the tape grass project. “If we don’t establish native plants soon, exotic vegetation, which often grow faster, can take hold.”
To keep grazers such as turtles from eating the newly-planted vallisneria, the FGCU team covered 12 plots of 30 plants each with inverted 3-foot-diameter plastic wading pools, whose bottoms had been cut out and replaced with wire mesh.
“The idea is to get dense plots established and protected, then remove the covers and monitor the sites,” Ceilley said. “With the muck gone, the water quality will improve, and we expect nothing but improvement over time.”
In addition to FGCU’s vallisneria efforts, the Florida Fish and Wildlife Conservation Commission will plant $250,000 worth of bulrush just shoreward of the vallisneria.
Lack of rain has dropped Lake Trafford’s water levels to about 3.5 feet below normal for this time of year, and state biologists are waiting for water levels to rise before starting to plant.
“Bulrush is an emergent plant – it grows up out of the water,” said biologist Jon Fury. “Vallisneria doesn’t grow up out of the water. Both are good for fish and wildlife habitat.
“Small invertebrates attach themselves to the bulrush. The invertebrates attract small fish, which attract bigger fish. We’ll plant it in the littoral zone, the shallow areas, where we find most fish reproduction and recruitment.”
As part of the Comprehensive Everglades Restoration Plan, demucking the lake and planting native vegetation will help habitats downstream.
“Places like Corkscrew Sanctuary will benefit,” Ceilley said. “But the primary mission is to restore recreational Bass Fishing Florida in the lake. That’s an important resource for this area. As a fish guy myself, I’m all for that.”
From Staff and Wire Reports