Abstract
Change in the coastal zone is accelerating with external forcing by sea-level rise, nutrient loading, drought, and over-harvest, leading to significant stress on the foundation plant species of coastal salt marshes. The rapid evolution of marsh state induced by these drivers makes the ability to detect stressors prior to marsh loss important. However, field work in coastal salt marshes can be challenging due to limited access and their fragile nature. Thus, remote sensing approaches hold promise for rapid and accurate determination of marsh state across multiple spatial scales. In this study, we evaluated the use of remote sensing tools to detect three dominant stressors on Spartina alterniflora. We took advantage of a barrier island salt marsh chronosequence in Virginia, USA, where marshes of different ages and level of stressor exist side by side. We collected hyperspectral imagery of plants along with salinity, sediment redox potential, and foliar nitrogen content in the field. We also conducted a greenhouse study where we manipulated environmental conditions. We found that models developed for stressors based on plant spectral response correlated well with salinity and foliar nitrogen within the greenhouse and field data, but were not transferable from lab to field, likely due to the limited range of conditions explored within the greenhouse experiments and the coincidence of multiple stressors in the field. This study is an important step towards the development of a remote sensing tool for tracking of ecosystem development, marsh health, and future ecosystem services.
Highlights
Salt marshes are a rapidly changing environment and are vulnerable to a variety of anthropogenic impacts including human manipulation, land conversion, invasive species, water-borne pollution, and global climate change, especially increased temperatures, changing precipitation patterns, and sea level rise [1,2,3,4]
We successfully developed models for a range of salinity and foliar N content using both vegetation indices and reflectance, but the models based on elastic net or stepwise regression did not predict oxidation-reduction potential (ORP) well in laboratory or field validation (Figure 5)
This study was the first step in developing indicators of salt marsh health using remote sensing
Summary
Salt marshes are a rapidly changing environment and are vulnerable to a variety of anthropogenic impacts including human manipulation, land conversion, invasive species, water-borne pollution, and global climate change, especially increased temperatures, changing precipitation patterns, and sea level rise [1,2,3,4]. Acute marsh die-off has increased, likely related to climate change-induced stressors and changes in trophic structure [2,5,6]. Coastal wetlands provide the greatest number of ecological services of any coastal environment, including support for coastal fisheries, important habitat, protection from storm surges, and reduction of nutrient loading to coastal water [7,8,9,10]. The dominant and foundation plant species in salt marshes of the Western Atlantic, has been significantly threatened in recent decades
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
