Lotic–lentic linkages associated with Lake Okeechobee, Florida

Abstract

The hydroscape of south Florida has been severely altered over the past 50 y by the construction of canals, drainage ditches, levees, water control structures, and pump stations. This alteration has included, in part, channelization of the Kissimmee River, construction of a dike around Lake Okeechobee, increased ditching of pastures for drainage throughout the lake’s watershed, and unnatural connections from Lake Okeechobee to estuaries on the east and west coasts of Florida. Collectively, these processes have reduced the retention of flow in the lake’s watershed, restricted the opportunity for nutrients to be assimilated on the landscape and, in turn, increased the rate of eutrophication in Lake Okeechobee. This paper reviews the history of these changes and current plans for system restoration. The fate and transport of P is used to illustrate how hydrologic changes have influenced the system’s ecology. Improved drainage has been a key factor allowing for the expansion of dairy and beef cattle operations. This, in turn, has increased agricultural runoff to Lake Okeechobee. Best management practices have helped reduce total P (TP) loads to the lake. However, TP concentrations in the pelagic region of the lake have not declined, presumably because of internal loading. Watershed and water-quality models are being used to examine the effect of changing land use in the watershed on the lake’s condition. A number of large, multiagency projects are being developed in south Florida, with the goal to develop a hydrologic system that meets the multiple needs of agriculture, urban development, and the environment. Aquatic linkages, including lotic–lentic, lotic–lentic–estuarine, and lotic–wetland, are critical aspects of these projects.BRIDGES is a recurring feature of J-NABS intended to provide a forum for the interchange of ideas and information between basic and applied researchers in benthic science. Articles in this series will focus on topical research areas and linkages between basic and applied aspects of research, monitoring policy, and education. Readers with ideas for topics should contact Associate Editors, Nick Aumen and Marty Gurtz.Benthic scientists usually focus their research within 1 type of aquatic ecosystem. However, junctions between lotic and lentic ecosystems are often physically, chemically, and biologically complex, and are important gateways to the matter and energy dynamics within either or both of the adjoining systems. A symposium on Lotic–Lentic Interactions, held on 5 June 1998 at the 46th Annual NABS Meeting in Charlottetown, Prince Edward Island, highlighted the research being done on this topic. Two of the papers from the symposium dealt with restoration and management projects and, as such, link basic and applied benthic research. These 2 papers are presented below. A. D. Steinman and B. H. Rosen present an overview of restoration efforts for the Kissimmee River/Lake Okeechobee hydroscape in south Florida in the context of historical land-use changes in the watershed. These changes have accelerated P loading and eutrophication in Lake Okeechobee. The effects are demonstrated by watershed and water-quality models. E. P. Benenati et al. examine linkages between the Lake Powell Reservoir and the downstream Colorado River. These authors show that the Colorado River benthic community is strongly affected by discharges from the Lake Powell Reservoir, caused by snowmelt pulses or experimental flooding. The 2 papers illustrate the need to carefully consider adjoining ecosystems in studies of lotic and lentic systems, and in management and restoration scenarios.A. HersheyA. D. SteinmanNick Aumen, [email protected]Marty Gurtz, [email protected]Co-editors