The USDA-NRCS Cape May Plant Materials Center:Advancing the Science and Plant Selection for Coastal Riparian Buffers

Abstract

Poorly managed upland land-use practices can increase the load of sediments, nutrients, and contaminants reaching coastal waters through runoff and riverine discharge. Vegetative riparian buffer systems are recognized as important conservation practices for implementation by landowners in near coastal areas. These coastal plant buffers function to provide an extra level of protection to working lands adjacent to bays and tidal tributaries. They are also designed to reduce the velocity of surface runoff, capture sediment, and reduce (assimilate) pollutant loads as well as provide valuable nesting and food habitat for wildlife. However, due to climate change, these areas are under increased stress due to rising sea levels, more frequent and intense storms, and increased salinity of coastal waters. These issues have encouraged scientists at the USDA-NRCS Cape May Plant Materials Center in cooperation with George Washington University, to initiate plant evaluation studies to support the improved function and resiliency of these buffer systems due to increased flooding and salinity stresses. Concurrently, both greenhouse and field studies are being conducted on a selection of native warm season grass species known to have some level of tolerance to salt concentrations in the soil and water. These species include switchgrass (Panicum virgatum), coastal panicgrass (Panicum amarum var. amarulum), eastern gamagrass (Tripsacum dactyloides) Prairie cordgrass (Spartina pectinata) and Florida paspalum (Paspalum floridanum). (Belt and Miller, 2021). In addition, a true halophyte (salt loving plant), saltmeadow cordgrass (Spartina patens) is also included in the study for comparative evaluation purposes. An initial salt tolerance screening evaluation is being done in a controlled greenhouse environment (Snell, 2020). This involves subjecting the plants to 3 different levels of salt concentrations and measuring root and top growth as well as chlorophyll levels, which is indicator of the amount of stress the plant is under. Field trials were established in 2021 to begin looking at the same species in-situ on salt and flood affected fields in the coastal plain of the Middle Atlantic states. Vegetation indices being collected include survival percentage, biomass production, and ground/foliar cover percentage. Soil data collected includes soil organic carbon and salt concentration. In addition, levels of salt in soil pore water will be analyzed within each of the individual species‘ plots. The most current data results (not available at this time) will be presented at the conference. Our work was conceived in part due to the cooperative work done with NRCS Caribbean Plant Materials Program and the University of Puerto Rico - Agricultural Experiment Station on potential use of halophyte buffers on agricultural land adjacent to salt flats in southwestern Puerto Rico (NRCS Cooperative Agreement #68-F352-09-02). The best performing species in that study for survival, spread (ground cover %), and biomass (foliar %) production was saltmeadow cordgrass (Spartina patens) which is the control plant species in our current studies (Gedan and Bertness, 2010).