S56. Investigating the response of coastal wetlands to sea-level rise (SLR): Understanding how macroscale drivers influence local processes and feedbacks

Coastal wetlands are complex ecogeomorphological systems that interact with a range of macroscale and local drivers which influence their sensitivity to environmental change (Braswell and Heffernan 2019). They are strongly connected to both upland watersheds and adjacent estuaries. They respond to changes in sediment transport, rates of sea-level rise, interactions with the ocean system, and changes in temperature. Understanding how local processes operate within heterogeneous coastal environments and interact with macroscale drivers is essential to forecasting marsh response to environmental change and understanding shifts in their resilience (Gabler et al. 2017, Sandi et al. 2018).

Sea-level rise (SLR) can lead to marsh loss through three mechanisms: lateral retreat, internal expansion of ponds and channels, and loss of marsh surface elevation relative to mean tide level (Fagherazzi et al. 2020).). However, our understanding of the future changes anticipated for coastal wetlands in the face of accelerations in SLR has been built on studies of “archetype” coastal wetlands (Osland et al. 2019). There is now a need to develop a more inclusive and synthetic framework that identifies how the interaction between local scale processes and larger scale macro drivers influence wetland vulnerability to environmental change. Developing a broad view of the role of site-specific processes, geomorphic settings, and macroscale drivers that operate across the gradient of coastal environments of the conterminous United States is critical if we are to guide well-informed decisions related to protection, restoration, and adaptation of coastal wetlands to SLR (Kelleway et al. 2017, Reed et al. 2018).

Research Opportunity

The USGS Eastern Ecological Research Center seeks a postdoctoral fellow that will help advance our understanding of coastal wetland responses to sea-level rise as part of a coupled earth atmosphere system and develop tools to transfer research to actionable science for coastal wetland managers to anticipate and prepare for the effects of future changes. We envision that the postdoctoral fellow will have strong quantitative data science skills (i.e. using machine learning approaches to make predictions, applying existing machine learning tools to model time-series dynamics, and applying machine learning to data analysis problems) and use their expertise in landscape ecology and coastal wetland ecosystem dynamics, in combination with innovative approaches for integrating existing geospatial data, to investigate complex problems revolving around the resilience of coastal wetlands to changes in sea-level rise, sediment supply, and other external forcing. The goal of this research opportunity is to investigate the resilience of coastal wetlands to changing environments by focusing on the interaction between macroscale drivers and local processes alongside the feedbacks between physical and ecological processes to improve our understanding of the general mechanisms affecting their resilience to disturbance. This can be achieved by advancing our understanding in several possible areas: (1) How does geomorphic setting influence marsh response to sea-level rise? (2) How do differences in marsh vegetation and/or marsh surface elevation influence marsh resiliency to sea-level rise? (3) How does the lateral extent and vertical stability of salt marshes experiencing rising sea levels depend on interacting drivers and feedbacks and geomorphic settings? (4) How can management and restoration efforts increase the ecological resilience of coastal wetlands in the face of sea-level rise? These questions can be approached using remote sensing approaches to evaluate coastal wetland geomorphic and vegetation patterns, spatial models of coastal wetland dynamics, and/or broad scale assessments of marsh resilience using existing data.

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.

References:

Braswell A.E. and J.B. Heffernan. 2019. Coastal wetland distributions: Delineating domains of macroscale drivers and local feedbacks. Ecosystems 22: 1256-1270. https://doi.org/10.1007/s10021-018-0332-3.

Fagherazzi, S., G. Mariotti, N. Leonardi, A. Canestrelli, W. Nardin, and W.S. Kearney. 2020. Salt marsh dynamics in a period of accelerated sea level rise. Journal of Geophysical Research: Earth Surface, 125, e2019JF005200. https://doi.org/10.1029/2019JF005200

Gabler, C.A., M.J. Osland, J.B. Grace, C.L. Stagg, R.H. Day, S.B. Hartley, N.M. Enwright, A.S. From, M.L. McCoy, and J.L. McLeod. 2017. Macroclimatic change expected to transform coastal wetland ecosystems this century. Nature Climate Change 7: 142–147.

Kelleway, J.J., K. Cavanaugh, K. Rogers, I. Feller, C. Doughty, N. Saintilan 2017. Review of the ecosystem service implications of mangrove encroachment into salt marshes. Global Change Biology 23: 3967-3983.

Osland, M.J., J.B. Grace, G.R. Guntenspergen, K.M. Thorne, J.A. Carr. 2019. Beyond Spartina alterniflora: the diversity and biogeography of foundation plant species in coastal wetlands of the conterminous United States. Estuaries and Coasts 42: 1991–2003.

Reed, D., van Wesenback, B., Herman, P. M. J., & Meselhe, E. (2018). Tidal flat-wetland systems as good defenses: Understanding biogeomorphic controls. Estuarine, Coastal, and Shelf Science, 213, 269-282. https://doi.org/10.1016/j.ecss.2018.08.017

Sandi, S.G., J.F. Rodriguez, N. Sainilan, and G. Riccardi. 2018. Rising tides, rising gates: The complex ecogeomorphic response of coastal wetlands to sea level rise and human interventions. Adances in Water Resources 114: 135-148.

Proposed Duty Station: Laurel, Maryland

Areas of PhD: Geology, biology, ecology, geography, mathematics, or related fields (candidates holding a Ph.D. in other disciplines but with extensive knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications:  Applicants must meet one of the following qualifications: Research Ecologist, Research Oceanographer, Research Hydrologist, Research Geophysicist, Research Geographer, Research Mathematician, or Research Statistician.

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Human Resources Office Contact:  Audrey Tsujita, 916-278-9395, atsujita@usgs.gov