The Everglades Ridge And Slough Landscape: A Linear Combination Between Boreal Bogs And Anabranching Rivers?
Larsen, Laurel G. 1 ; Harvey, Judson W. 2 ; Crimaldi, John P. 3
1 University of Colorado
2 U.S. Geological Survey, Reston, VA
3 University of Colorado
The ridge and slough landscape of the Florida Everglades is a patterned peatland, with elevated sawgrass ridges interspersed among open-water sloughs, aligned with the flow direction. Throughout a century of drainage and compartmentalization, the landscape has degraded, and restoration efforts seek to preserve remnant topographic heterogeneity. Mechanisms for pattern formation and maintenance, however, are not understood (SCT, 2003). PeatAccrete 1.0 is a numerical simulation of potential feedback between species-specific net rates of peat production, hydroperiod, and nutrient concentration. Model results (Fig. 1) indicate that, as in boreal bogs (Nungesser, 2003), this feedback mechanism can govern vertical topographic differences and the attainment of an equilibrium ridge height. It cannot, however, account for longitudinal expansion and the attainment of an equilibrium ridge width. Based on a literature synthesis and discrepancies between model results and observed geomorphology, it is proposed that an anabranching river-type feedback between morphologic profile, sediment entrainment, and sediment deposition governs these latter geometric features (Fig. 2). PeatAccrete model results and the adoption of an anabranching river paradigm provide insight into restoration decisions and indicate that restoration of flow, hydroperiod, and natural redox conditions can result in a reproduction of the historical landscape in locations with remnant topographic heterogeneity.
Nungesser, M.K. 2003, Modelling microtopography in boreal peatlands: hummocks and hollows: Ecological Modelling, v. 165, p. 175-207.
Science Coordination Team, 2003, The Role of Flow in the Everglades Ridge and Slough Landscape. Available http://sofia.usgs.gov/publications/papers/sct_flows/.
Tooth, S., G.C. Nanson, 2000, The role of vegetation in the formation of anabranching channels in an ephemeral river, Northern plains, arid central Australia: Hydrological Processes, v. 14, p. 3099-3117.