Effects of water hardness on slough-wet prairie plant communities of the A. R. M. Loxahatchee National Wildlife Refuge

Alterations to ground-water and surface-water hydrology and water chemistry in South Florida have contributed to increased flows of mineral-rich (hard water) canal water into historically rain-fall driven (soft water) areas of the Everglades. The interior of the A. R. M. Loxahatchee National Wildlife Refuge largely has retained its historic low conductivity or soft water condition due to its relative isolation from canal flows. However, recent sampling by USGS and the Refuge has shown that canal influences on water quality extend several kilometers into the Refuge in some areas, and Refuge managers and scientists are concerned that these influences may increase depending on future changes in water management operations.

A survey across existing mineral gradients will be performed to document patterns of vegetation change and their relationship to changes in water hardness and other environmental factors. Laboratory and field experiments will test these correlative relationships to determine the relative importance of increasing water hardness as a cause of observed vegetation changes across canal gradients.