![]() ![]() The islands stored several times the annual inflow of total phosphorus (TP, 3.1 times) and Total Nitrogen (TN, 6.5 times) and thus could potentially affect the lake's trophic state by leaching nutrients. Our study was designed to determine: (1) amount of nutrients stored in islands relative to annual inflows, (2) nutrient release to the lake from the islands, and (3) changes in lake trophic state due to the muck scraping and construction of the islands.The lake enhancement project was completed in late summer 2004, and the average thickness of organic materials in the scrapped areas was reduced from 46 cm to 1.6 cm, improving access and aesthetics tremendously. Most of this material was heaped into large piles in shallow parts of the lake to form 29 artificial islands with basal areas from 0.4 to 3.3 ha each. To remove organic accumulation, the lake water level was dropped and heavy equipment was used to scrape the plants and dead organic materials from the underlying sand substrates from more than 1,420 ha of the littoral zone. Muck build up has also reduced aesthetics and boat access. Those shoreline areas were often devoid of oxygen, and the muck buildup filled feeding grounds for wading birds and spawning fish. Cultural eutrophication and lake water level stabilization led to accelerated growth of invasive native and non-native aquatic macrophytes, resulting in the buildup of thick deposits of organic matter along the shoreline. Lake Tohopekaliga is a large (surface area 9,800 ha) and shallow (mean depth 2.1 m) natural lake in central Florida. ![]() Continued efforts are needed to place into public ownership remaining privately owned coastal wetland property to allow implementation of best management practices on these important habitats. This has occurred largely by implementing management and restoration techniques that minimize environmental impacts, allow for mosquito control, and minimize the need for pesticide use. Through the efforts of these committees, a heavy investment in research, interagency cooperation, and public acquisition of coastal wetlands property, tremendous progress has been made in management of coastal wetlands. This resulted in the Florida Legislature creating the Florida Coordinating Council on Mosquito Control and its Subcommittee on Managed Marshes. In the early 1980s, efforts to encourage coastal wetlands management for both mosquito control and environmental interests came to the forefront. Coastal wetland management efforts in Florida, which date back to the 1920s, have included ditching, dredging and filling, and impounding, all having mosquito control and environmental benefits and liabilities. However, the impact of high saltmarsh mosquito numbers on the well-being of residents and visitors cannot be underestimated. While mosquito-transmitted diseases have played a major role in Florida’s history, saltmarsh mosquitoes have not been implicated in these disease outbreaks. High mosquito populations have always been a part of Florida’s environment. Additionally, aquatic plants were identified at coring sites sampled in 2015 to determine if sediment accumulation rates were different in areas dominated by specific plant types and/or species, and no significant differences were found. At that accumulation rate it would take approximately 210 yr (191 to 238, 95% confidence interval) to reach the original 46 cm of littoral muck, and these data suggest that the muck removal program will not have to be repeated for many years. ![]() From 2005 to 2015 there was a whole-lake average of 2.2 cm of organic sediment accumulated, yielding a rate of 0.22 (0.18 to 0.24, 95% confidence interval) cm yr(-1) for the decade. To address concerns about the longevity of this management activity, sediment cores were taken again at 130 of the original sites in August 2008 and January 2015 to estimate sediment accumulation rates. In 2005 sediment cores were taken from 145 sites located throughout the scraped littoral area, showing an estimated 1.6 cm of organic sediment after the removal program. In 2004 a multimillion dollar muck removal program was completed that targeted an estimated average 46 cm of muck in 1,420 ha of littoral area in Lake Tohopekaliga, FL. ![]()
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