Glenn Guntenspergen, Ph.D.
Science and Products
The Challenge: Accelerations in sea-level rise and changing environmental stressors have important implications for the integrity of coastal wetlands and for efforts to restore and protect the ecosystem services they provide. Their persistence and adaptation to these stressors depends on the net effects of changes in physical processes and biotic responses. Future planning by decision makers will require scientifically sound forecasts of potential impacts, knowledge of sea-level rise thresholds, and indications of the potential effectiveness of various adaptation strategies.
The Challenge: The integrity and sustainability of salt marshes in National Park units of the Northeast Coastal and Barrier Network (NCBN) are severely threatened by human activities. These marshes provide critical fish and wildlife habitat and essential ecosystem services in the northeastern coastal zone, and are a high priority for NCBN Vital Signs monitoring. Biennial monitoring of nekton (i.e., fish and free-swimming crustaceans) and vegetation has been conducted in NCBN parks since 2008. There is now a critical need for tools to integrate Vital Signs measures in a way that allows assessment of the overall condition of park salt marshes.
The Challenge: The high winds and storm surge associated with Hurricane Sandy impacted coastal wetlands from Virginia to Maine. Understanding the ecological and geological impacts of hurricanes on coastal wetlands and their interactive effects with local conditions is important for identifying resilience of these communities to predicted global sea-level rise. Given the projected increase in number and intensity of hurricanes, we need to understand the impact of physical and chemical stressors associated with hurricanes in order to efficiently and effectively protect and restore these critical habitats. Storm-related sediment deposition and erosion are two of the potential long-term impacts of severe storms such as Hurricane Sandy on marsh surface elevation and resilience. But wetland impacts are unique for every major storm because of each storm’s unique characteristics (wind speed, angle of approach, tidal stage).
We measured the response of plants to disturbance across a gradient in inundation times by transplanting tussocks of Schoenoplectus americanus into mesocosms of different elevation in two marsh organ platforms.
This dataset is comprised of eight files related to salt marsh monitoring data or measures of of human disturbance (i.e. human impacts in terms of physical, chemical, and land-use stressors) collected at 33 marsh study units (MSUs) in five National Parks within the NPS Northeast Coastal and Barrier Network (NCBN) along the NE coast of the US.
Development of a multimetric index for integrated assessment of salt marsh ecosystem condition
Tools for assessing and communicating salt marsh condition are essential to guide decisions aimed at maintaining or restoring ecosystem integrity and services. Multimetric indices (MMIs) are increasingly used to provide integrated assessments of ecosystem condition. We employed a theory-based approach that considers the multivariate relationship...Nagel, Jessica L.; Neckles, Hilary A.; Guntenspergen, Glenn R.; Rocks, Erika N.; Schoolmaster, Donald; Grace, James B.; Skidds, Dennis; Stevens, Sara
Inundation, vegetation, and sediment effects on litter decomposition in Pacific Coast tidal marshes
The cycling and sequestration of carbon are important ecosystem functions of estuarine wetlands that may be affected by climate change. We conducted experiments across a latitudinal and climate gradient of tidal marshes in the northeast Pacific to evaluate the effects of climate- and vegetation-related factors on litter decomposition. We...Janousek, Christopher; Buffington, Kevin J.; Guntenspergen, Glenn R.; Thorne, Karen M.; Dugger, Bruce D.; Takekawa, John Y.
Decomposition of plant litter in Pacific coast tidal marshes, 2014-2015
Decomposition of plant matter is one of the key processes affecting carbon cycling and storage in tidal wetlands. In this study, we evaluated the effects of factors related to climate change (temperature, inundation) and vegetation composition on rates of litter decay in seven tidal marsh sites along the Pacific coast. In 2014 we conducted...Janousek, Christopher; Buffington, Kevin J.; Guntenspergen, Glenn R.; Thorne, Karen M.; Dugger, Bruce D.; Takekawa, John Y.
Spatio-temporal development of vegetation die-off in a submerging coastal marsh
In several places around the world, coastal marsh vegetation is converting to open water through the formation of pools. This is concerning, as vegetation die-off is expected to reduce the marshes' capacity to adapt to sea level rise by vegetation-induced sediment accretion. Quantitative analyses of the spatial and temporal development of marsh...Schepers, Lennert; Kirwan, Matthew; Guntenspergen, Glenn R.; Temmerman, Stijn
Fine-resolution conservation planning with limited climate-change information
Climate change related uncertainty in future spatial patterns of conservation-related outcomes make it difficult to implement standard conservation and land-use planning paradigms. A recent study translates Markowitz’s risk diversification strategy from finance to conservation settings, enabling policy makers and conservation agents to use this...Shah, Payal; Mallory, Mindy L.; Ando , Amy W. ; Guntenspergen, Glenn R.
Modeling the effects of tile drain placement on the hydrologic function of farmed prairie wetlands
The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in...Werner, Brett; Tracy, John; Johnson, W. Carter; Voldseth, Richard A.; Guntenspergen, Glenn R.; Millett, Bruce
Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes
Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes...Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.
Effects of climate change on tidal marshes along a latitudinal gradient in California
Public SummaryThe coastal region of California supports a wealth of ecosystem services including habitat provision for wildlife and fisheries. Tidal marshes, mudflats, and shallow bays within coastal estuaries link marine, freshwater and terrestrial habitats, and provide economic and recreational benefits to local communities. Climate change...Thorne, Karen M.; MacDonald, Glen M.; Ambrose, Rich F.; Buffington, Kevin J.; Freeman, Chase M.; Janousek, Christopher N.; Brown, Lauren N.; Holmquist, James R.; Guntenspergen, Glenn R.; Powelson, Katherine W.; Barnard, Patrick L.; Takekawa, John Y.
Potential effects of sea-level rise on plant productivity: Species-specific responses in northeast Pacific tidal marshes
Coastal wetland plants are adapted to varying degrees of inundation. However, functional relationships between inundation and productivity are poorly characterized for most species. Determining species-specific tolerances to inundation is necessary to evaluate sea-level rise (SLR) effects on future marsh plant community composition, quantify...Janousek, Christopher; Buffington, Kevin J.; Thorne, Karen M.; Guntenspergen, Glenn R.; Takekawa, John Y.; Dugger, Bruce D.
Overestimation of marsh vulnerability to sea level rise
Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or...Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio
Greenhouse gas fluxes from salt marshes exposed to chronic nutrient enrichment
We assessed the impact of nutrient additions on greenhouse gas fluxes using dark static chambers in a microtidal and a macrotidal marsh along the coast of New Brunswick, Canada approximately monthly over a year. Both were experimentally fertilized for six years with varying levels of N and P. For unfertilized, N and NPK treatments, average yearly...Chmura, Gail L.; Kellman, Lisa; van Ardenne, Lee; Guntenspergen, Glenn R.
Impacts of climate change on land-use and wetland productivity in the Prairie Pothole Region of North America
Wetland productivity in the Prairie Pothole Region (PPR) of North America is closely linked to climate. A warmer and drier climate, as predicted, will negatively affect the productivity of PPR wetlands and the services they provide. The effect of climate change on wetland productivity, however, will not only depend on natural processes (e.g.,...Rashford, Benjamin S.; Adams, Richard M.; Wu, Jun; Voldseth, Richard A.; Guntenspergen, Glenn R.; Werner, Brett; Johnson, W. Carter