Vegetation Mosaic of Ragged Rock Creek Brackish Tidal Marsh, Connecticut River, Old Saybrook, CT: A Final Report to the Department of Environmental Protection, State of Connecticut

摘要

This study used the detailed plots-based floristic descriptions of traditional phytosociology to inform scenes of high resolution imagery to characterize and map, in detail, the brackish tidal wetland plant communities of Ragged Rock Creek. An emphasis was placed on providing a baseline geographic context for plants of conservation and management interest, i.e., both state-listed plants and invasive plants. The results provided a baseline vegetation assessment and map prior to invasive Phragmites australis (common reed) control and restoration by onsite re-vegetation. Representative samples of 10 major community types, derived from hierarchical cluster analysis and fidelity tests, were used to determine the spectral profiles from high resolution ADS40 RBG/CIR images and LiDAR top of canopy return, that in tum, were used to inform an object-based software technique to generate a detailed vegetation map. The map was validated using a conventional contingency table approach, with mixed results, mostly coinciding with the frequency and size of the community patch. Our dense array of 926 precisely georeferenced plots, photographs, quantitative vegetation data, and voucher specimens, provide a robust baseline which will enable an evaluation of the marsh response in the future to management, climate change, sea-level rise, or other phenomena. This study demonstrated the utility of this approach for mapping large and heterogeneous wetland complexes and taking baselines for management and monitoring actions.