Forecasting effects of sea-level rise and windstorms on coastal and inland ecosystems

Author Posting. © Ecological Society of America, 2008. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Frontiers in Ecology and the Environment 6 (2008): 255–263, doi:10.1890/070153.We identify a continental-scale network of sites to evaluate how two aspects of climate change – sea-level rise and intensification of windstorms – will influence the structure, function, and capacity of coastal and inland forest ecosystems to deliver ecosystem services (eg carbon sequestration, storm protection, pollution control, habitat support, food). The network consists of coastal wetland and inland forest sites across the US and is representative of continental-level gradients of precipitation, temperature, vegetation, frequency of occurrence of major windstorms, value of insured properties, tidal range, watershed land use, and sediment availability. The network would provide real-time measurements of the characteristics of sea-level rise and windstorm events and would allow an assessment of the responses of wetlands, streams, and inland forests at spatial and temporal scales associated with sustainability of ecosystem services. We illustrate the potential of this approach with examples of hypotheses that could be tested across the network.The research that led to this paper was supported in part by grants to CSH (NSF BCS-0709685, DEB-0614282, OCE-0423565, GA Sea Grant NA080AR4170724), AEL (NSF BIR-8811902, DEB-9411973, DEB-9705814, DEB-0080538, DEB- 0218039), MA (NSF OCE-0620959, GA Sea Grant NA08OAR4170724, GA Coastal Management Program NA07NOS4190182), APC (NSF DEB-0218039), and SJVB (USDA CSREES PR00NRI001, McIntire Stennis PR014)

Marine Ecoregion and Deepwater Horizon Oil Spill Affect Recruitment and Population Structure of a Salt Marsh Snail

Marine species with planktonic larvae often have high spatial and temporal variation in recruitment that leads to subsequent variation in the ecology of benthic adults. Using a combination of published and unpublished data, we compared the population structure of the salt marsh snail, Littoraria irrorata, between the South Atlantic Bight and the Gulf Coast of the United States to infer geographic differences in recruitment and to test the hypothesis that the Deepwater Horizon oil spill led to widespread recruitment failure of L. irrorata in Louisiana in 2010. Size-frequency distributions in both ecoregions were bimodal, with troughs in the distributions consistent with a transition from sub-adults to adults at ~13 mm in shell length as reported in the literature; however, adult snails reached larger sizes in the Gulf Coast. The ratio of sub-adults to adults was 1.5–2 times greater in the South Atlantic Bight than the Gulf Coast, consistent with higher recruitment rates in the South Atlantic Bight. Higher recruitment rates in the South Atlantic Bight could contribute to higher snail densities and reduced adult growth in this region. The ratio of sub-adults to adults in Louisiana was lower in 2011 than in previous years, and began to recover in 2012–2014, consistent with widespread recruitment failure in 2010, when large expanses of spilled oil were present in coastal waters. Our results reveal an important difference in the ecology of a key salt marsh invertebrate between the two ecoregions, and also suggest that the Deepwater Horizon oil spill may have caused widespread recruitment failure in this species and perhaps others with similar planktonic larval stages

South Atlantic Regional Research Plan: Development and Application of Coastal Regional Priorities

Proceedings of the 2011 Georgia Water Resources Conference, April 11, 12, and 13, 2011, Athens, Georgia.The South Atlantic Regional Research Project (SARRP, http://www.gcrc.uga.edu/sarrp.htm) is a regional, multi-agency project to develop a coordinated coastal and ocean research plan for the southeastern United States (from NC to FL). The South Atlantic effort was funded by National Sea Grant-NOAA and was conducted in concert with similar projects in other Sea Grant regions across the US and Insular Pacific. The project’s primary goals are to identify priority coastal and ocean research needs for the region and to foster productive cooperation among regional partners. The SARRP plan was released in April 2010 after a three-year process that involved federal, regional, state and academic partners from throughout the region. The plan identifies 27 research priorities, which were aligned with the four themes that are also being used by the South Atlantic Governor’s Alliance: Healthy Ecosystems, Working Waterfronts, Clean Coastal and Ocean Waters, and Disaster-Resilient Communities. We are currently collecting information describing ongoing or planned activities that are relevant to each priority, as well as identifying areas specifically aligned with the missions of particular agencies and organizations. This paper will describe the process by which the plan was developed, highlighting the key research priorities identified in the research plan and presenting an update on synergy with other regional initiativesSponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources FacultyThis book was published by Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, Georgia 30602-2152. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-307) or the other conference sponsors

Spartina Species Zonation along the Altamaha River Estuary

Proceedings of the 2003 Georgia Water Resources Conference, held April 23-24, 2003, at the University of Georgia.Changes in freshwater inflow can cause changes in the distribution and diversity of marsh vegetation in estuarine habitats. In the fall of 2002 bankside vegetation was surveyed along the 24 km length of the Altamaha River estuary (n= 14 sites). Sites were quantified for multiple plant and edaphic parameters, including plant density, height, and tiller diameter. In this paper we present the characteristics of the bankside marsh vegetation as they change along the estuarine salinity gradient, and evaluate the use of a proportional relationship between two marsh grasses, Spartina cynosuroides and S. alterniflora, as a way to identify a transition line between salt and brackish marsh communities. S. alterniflora densities were greatest at the mouth of the estuary and decreased upstream and S. cynosuroides densities showed the opposite pattern, but there was not a well defined transition between these two plant communities. The percent S. cynosuroides cover along the estuary is a potentially useful way to document the response of the estuary to changing amounts of freshwater inflow

Water Use Patterns in the Watersheds of the Georgia Riverine Estuaries

Proceedings of the 2001 Georgia Water Resources Conference, April 26 and 27, 2001, Athens, Georgia.We examined water use patterns in the hydrologic units that comprise the watersheds of the 5 major coastal rivers in Georgia (Savannah, Ogeechee, Altamaha, Satilla, St. Marys). The data for this analysis were obtained from the Georgia Water Use Program, which regularly surveys both water sources (groundwater and surface water) and water uses (domestic, commercial, industrial, mining, irrigation, livestock, thermoelectric, and hydroelectric) as part of the USGS National Water Use Synthesis. Total water withdrawal in the study area totaled 5749 million gallons per day (mgd) in 1995, with no large changes in either water withdrawal or water use patterns for the last 3 reporting years (1985, 1990, and 1995). Surface water accounted for 91% of the water withdrawal in the region, and much of this was for thermoelectric use in the watersheds of the Savannah and Altamaha Rivers. However, most of the groundwater that was withdrawn was withdrawn in the Coastal Plain. Only 10% of the water withdrawn was actually consumed, with the remainder returned to the surface water. Irrigation represented the largest consumptive use, and much of this occurred in the Coastal Plain.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, Natural Resources Conservation Service, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397) or the other conference sponsors

A Vegetative Survey of Back-Barrier Islands near Sapelo Island, Georgia

Proceedings of the 2003 Georgia Water Resources Conference, held April 23-24, 2003, at the University of Georgia.This study was designed to examine the forest composition, structure and species richness of vegetation among undeveloped back-barrier islands near Sapelo Island, Georgia. Known colloquially as “marsh hammocks,” back-barrier islands are completely or partially encircled by estuarine saltmarsh. There are upwards of 1200 hammocks along the Georgia coast, comprising approximately 6900 ha. In the face of increased development pressure, the cumulative impacts caused by small-scale construction of homes, roads, bridges, and septic fields may alter natural hydrologic and ecological processes. We surveyed vegetation on 11 undeveloped hammocks in four size classes and found that overall species diversity is low, but the diversity of vascular plants may increase with island size. Local and regional planners and conservation organizations may use this information to help develop land-based projects that are consistent with the sustainable use of coastal resources

Coastal Watershed Condition Assessment of Fort Pulaski National Monument

Proceedings of the 2007 Georgia Water Resources Conference, March 27-29, 2007, Athens, Georgia.We recently completed an assessment of Fort Pulaski National Monument for the Water Resources Division of the National Park Service. The report provides information on park resources, water quality and impairments, and other issues of concern. Although there are no real sources of pollutants at Fort Pulaski itself, both point and nonpoint sources of pollutants can be found nearby that have the potential to affect its water resources. We identified nutrients and contaminants as currently existing problems. A majority of nutrient samples were classified as either fair or poor, and there is evidence for elevated contaminants (primarily arsenic and PAHs) in sediment and animal tissue taken from both tidal creeks and the main channel of the Savannah River. Dissolved oxygen was identified as a potential problem due to the amount of organic material and nutrients associated with industrial activity. Fecal bacteria concentrations are low and not considered a problem. Continued water quality monitoring at the Park is particularly important in order to note any change occurring with the Savannah Harbor Expansion Project. The report provides a list of recommendations for additional observations that would allow us to better evaluate coastal water resources.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, Natural Resources Conservation Service, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397) or the other conference sponsors

Comparing transport times through salinity zones in the Ogeechee and Altamaha River estuaries using squeezebox

This study explored differences in the transit times of dissolved substances through salinity zones in the Altamaha and Ogeechee River estuaries under a range of flow conditions. Salinity distributions and transit times were estimated from box models generated using the SqueezeBox modeling framework. The estuaries were compared in spite of the large difference in their river flow ranges by using flow rates ranging from the 10th-90th percentile within each range. In each case, zone lengths and transit times were calculated for the tidal freshwater, oligo-mesohaline, and polyhaline zones. Although the two estuaries have similar lengths, the slower-flowing Ogeechee grades from a zone of tidal freshwater (except at very low flows) through oligo-mesohaline zones to a polyhaline zone inside the mouth whereas the Altamaha always has a fairly long (>25 km) extent of tidal freshwater but only a short (or non-existent) polyhaline zone. Transit times through the whole Ogeechee estuary are 3.3-4.7 times longer than those in the Altamaha, but the lengths of time water spends in the tidal freshwater reaches of the estuaries are comparable whereas there are large differences in the times spent in oligo-mesohaline and polyhaline reaches. These types of predictions may be useful in interpreting nutrient and pollutant dynamics in estuaries as well as in studies that compare the relative susceptibility of estuaries to perturbations.Sponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources Facult

Trends in agricultural sources of nitrogen in the Altamaha River watershed

We compiled USDA Census of Agriculture data on livestock production and agricultural land use along with USGS estimates of fertilizer use to evaluate trends in agricultural sources of nitrogen (N) to the watershed of the Altamaha River. Between 1954 and 2002, the estimated contribution of N from the three major livestock crops (cattle, chickens, and pigs) remained fairly stable, averaging approximately 1,000 kg N/km2. However, the source of the waste shifted from primarily cattle in 1954 to a mix of cattle and chickens in 2002, due in large part to a ten-fold increase in the number of chickens in the watershed. We did not have fertilizer data through 2002, but between 1954 and 1991 estimated fertilizer N use doubled, from 503 to 1,055 kg N/km2 (calculated based on the area of the watershed). These changes in N sources were accompanied by decreases in the amount of cultivated land in the watershed. The amount of land classified as harvested cropland decreased from 6,528 in 1954 to 2,448 km2 in 1992, which suggests there has been an increase in the amount of fertilizer applied per unit area. The amount of pastureland showed an even larger decrease, from 11,421 in 1954 to 3,294 km2 in 2002, which we take as evidence of increased confinement of livestock. When these numbers are considered in the context of all of the sources of N to the watershed, we estimate that the proportion of agricultural-derived N accounted for approximately 66% of the N input to the watershed in 2000, with the remainder coming from human waste and atmospheric deposition.Sponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources Facult

Trends in Salinities and Flushing Times of Georgia Estuaries

Proceedings of the 1999 Georgia Water Resources Conference, March 30 and 31, Athens, Georgia.From 1973-1992, the Georgia EPD sponsored a monitoring program in which surface salinities were sampled regularly at fixed stations in many of Georgia's estuaries. We used these data to examine changes in the salinities and flushing times of the Savannah, Ogeechee, Altamaha, · Satilla, and St. Marys estuaries over the period of record. Water-year average salinities increased slightly over time in four of the five estuaries. When data were smoothed with a three-year moving average (based on fast Fourier analysis of river discharge), the increases in salinity were statistically significant in the Satilla and Savannah River estuaries. We used the measured salinity values to estimate flushing times (average transit time of river water through an estuary) over the period of record. Flushing times averaged 28 d in the Ogeechee, 7 din the Altamaha, 63 d in the Satilla, and 65 d in the St. Marys, although there was considerable inter-annual variability in these estimates. These results are discussed in light of current proposals to increase surface water withdrawal from the Georgia rivers.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202 with partial funding provided by the U.S. Department of Interior, geological Survey, through the Georgia Water Research Insttitute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors