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Abstract Large datasets, combined with modeling techniques, provide a quantitative way to estimate when known archaeological sites will be impacted by climatological changes. With over 4,000 archaeological sites recorded on the coast of Georgia, USA, the state provides an ideal opportunity to compare methods. Here, we compare the popular passive “bathtub” modeling with the dynamic Sea Level Affecting Marshes Model (SLAMM) combined with the Marshes Equilibrium Model (MEM). The goal of this effort is to evaluate prior modeling and test the benefits of more detailed ecological modeling in assessing site loss. Our findings indicate that although rough counts of archaeological sites destroyed by sea-level rise (SLR) are similar in all approaches, using the latter two methods provides critical information needed in prioritizing site studies and documentation before irrevocable damages occur. Our results indicate that within the next 80 years, approximately 40% of Georgia's coastal sites will undergo a loss of archaeological context due to wetlands shifting from dry ecological zones to transitional marshlands or submerged estuaries and swamps. 

Abstract Ecosystem connectivity tends to increase the resilience and function of ecosystems responding to stressors. Coastal ecosystems sequester disproportionately large amounts of carbon, but rapid exchange of water, nutrients, and sediment makes them vulnerable to sea level rise and coastal erosion. Individual components of the coastal landscape (i.e., marsh, forest, bay) have contrasting responses to sea level rise, making it difficult to forecast the response of the integrated coastal carbon sink. Here we couple a spatially-explicit geomorphic model with a point-based carbon accumulation model, and show that landscape connectivity, in-situ carbon accumulation rates, and the size of the landscape-scale coastal carbon stock all peak at intermediate sea level rise rates despite divergent responses of individual components. Progressive loss of forest biomass under increasing sea level rise leads to a shift from a system dominated by forest biomass carbon towards one dominated by marsh soil carbon that is maintained by substantial recycling of organic carbon between marshes and bays. These results suggest that climate change strengthens connectivity between adjacent coastal ecosystems, but with tradeoffs that include a shift towards more labile carbon, smaller marsh and forest extents, and the accumulation of carbon in portions of the landscape more vulnerable to sea level rise and erosion.