QUATERNARY CONTRIBUTIONS TO 21ST CENTURY RESTORATION PROJECTS: AN EXAMPLE FROM THE EVERGLADES

Resource managers around the world are faced with the challenge of restoring ecosystems across a range of environments and spatial scales. A common goal of these efforts is to return ecosystems to a pre-existing unaltered state, but this raises the question of how to identify these conditions to establish restoration targets. Instrumental and observational data of past conditions, if they exist, are typically limited to the last half century and post-date significant anthropogenic disturbance. Quaternary sediment core archives preserve information about decadal to millennial scale dynamics of ecosystems – information necessary for resource managers to identify baselines and set sustainable restoration goals. More importantly, long term data sets provide an alternative to using pre-existing conditions by identifying natural trajectories or cycles of change. Predictions of the state of the ecosystem without disturbance can be developed and targets can be set with the goal of returning the system to the natural trend at some point in the future. In Everglades restoration, Quaternary archives are used to examine the role of climate, sea level, habitat and species resilience, and freshwater availability in driving natural change within the ecosystem over the last ~5000 years.

Restoration of natural freshwater flow through the wetlands and into the estuaries is one of the primary goals of Everglades restoration. Paleosalinity data derived from analysis of estuarine cores are linked to statistical models based on observed hydrologic data to determine pre-disturbance salinity in the estuaries and freshwater flow and stage in the wetlands of the Everglades. These data provide a baseline that is currently used by resource managers to set short-term salinity targets for the estuaries. Our goal, however, is to examine the interconnected role of climate, sea level and freshwater availability to provide managers with targets projected out 30 to 50 years (time frame of Everglades restoration). In south Florida, restoration of freshwater flow that does not take sea level rise into account will not be sustainable. By applying Quaternary science to restoration projects around the world, resource managers will be able to set realistic and sustainable goals that take the anticipated changes of the 21^st century into account.