A collaboration between Villanova University, University of Central Florida, and the GTMNERR
Roots and Rakes is a project in direct response to the outcomes of Experimenting with Elevation, in which we determined that boat wakes may be driving oyster shell accumulation along the banks of the Intracoastal Waterway in the GTMNERR. These oyster shell berms, or rakes, can impact marsh health and nutrient cycling, thereby resulting in increased wetland vulnerability. Using pilot sites along the intracoastal waterway, we explore the impacts of shell rakes on marsh health and nutrient cycling.
We set up four Roots and Rakes sites based on the coastal vulnerability map we developed as part of the NERRS Science collaborative catalyst project. Each site contained a combination of stable and unstable marsh plots (see examples of each in top right corner). Site 3 contained only stable plots and represented a stable endpoint site (bottom right). Plant measurements at each site included heights, densities, and root ingrowth.
Project Goal 1:
Determine the impact of shell rakes on marsh nutrient cycling, plant and soil stress, and elevation.
Goal 1 Outcomes:
We found that neither the height nor the density of the dominant salt marsh grass Spartina alterniflora in the GTMNERR Roots and Rakes sites predicted marsh stability. We have developed a new index, cumulative marsh height (marsh plant height x density) that accurately captures the lower overall marsh plant success in unstable plots. Across two seasons, marsh plant cumulative height was about 50% lower in unstable plots, indicating less plant biomass compared to stable plots.
Root productivity of Roots and Rakes stable and unstable plots compared to other experimental sites in the GTMNERR. No statistics are shown but overall unstable marsh plots had lower root productivity rates (g/m2/month) than other plots measured across the reserve.
Project Goal 2:
Integrate new water quality and nutrient data with an existing coastal vulnerability assessment to facilitate site-specific conservation and restoration planning.
Goal 2 Outcomes:
Using 38 years of water quality data within the GTMNERR, we identified the seasonal, annual, and long-term trends in concentrations of common Nitrogen and Phosphorus compounds across the estuary. Click here to access the StoryMap detailing our findings.
Click here to see photos from our first day of preliminary data collection!