Invasive alien aquatic plants in South African freshwater ecosystems

FWN – Publicaties zonder aanstelling Universiteit Leide

Phytoplankton productivity in a southeastern cooling reservoir: Temporal and spatial variability

Documenting the temporal and spatial dynamics of phytoplankton productivity in reservoirs is essential to understanding the functioning of these ecosystems and developing appropriate management schemes. Few such data have been published for southeastern reservoirs. A record of productivity measurements spanning 19 years exists for Par Pond, a 1000 ha cooling reservoir located on the Department of Energy's Savannah River site in South Carolina. From 1965 to 1984, mean annual productivity ranged from 118 to 777 mg C/m{sup 2}/day. Differences among years correlated strongly with fluctuations in mean conductivity. Conductivity, in turn, was influenced by changes in the volume and quality of Savannah River water added to Par Pond to compensate for evaporative losses. To characterize the variability of productivity in this system, statistical and graphical summaries are presented for different temporal and spatial scales. 7 refs., 6 figs., 1 tab

Integrated Ecological Modeling and Decision Analysis Within the Everglades Landscape

Planning for complex ecosystem restoration projects involves integrating ecological modeling with analysis of performance trade-offs among restoration alternatives. The authors used the Everglades Landscape Model and Multi-Criteria Decision Analysis to explore the effect of simulated ecosystem performance, risk preferences, and criteria weights on the ranking of three alternatives to restoring overland sheet flow in the Everglades. The ecological model outputs included both hydrologic and water quality criteria. Results were scored in the decision analysis framework, highlighting the trade-offs between hydrologic restoration and water quality constraints. Given equal weighting of performance measures, the alternative with more homogenous sheet flow was preferred over other alternatives, despite evidence of some localized eutrophication risk