Hudson River Fishes and their Environment

Hudson River Paleoecology from Marshes: Environmental Change and its Implications for Fisheries

Dorothy M. Peteet, Dee Cabaniss Pederson, Dorothy Kurdyla, and Tom Guilderson

doi: https://doi.org/10.47886/9781888569827.ch7

Abstract.—Hudson riverine and coastal marshes provide a paleoecological archive consisting of information on climate and land use at both the local and watershed scales. The timing of formation of these marshes is documented using accelerator mass spectrometry (AMS) ¹⁴C dating of identified plant macrofossils in basal marsh organic sediments. While the Staten Island marsh is oldest and dates to 11,000 years before present (BP), Piermont, Iona, and Croton marshes date to the mid-Holocene, and the Jamaica Bay marshes formed most recently. Pollen and spores, charcoal, and plant macrofossils in the marsh sediments document marked climatic shifts as well as anthropogenic impact in the region. Assessment of the inorganic and organic content of the sediments in the marshes reveals a pattern of decreasing inorganic supply with the arrival of the Europeans, possibly due to the construction of numerous Hudson River tributary dams. Piermont Marsh, because of its sensitive location in the Hudson River, records droughts and wet intervals through species which have specific salinity affinities. Throughout the marsh records, the ragweed Ambrosia pollen rise marks the anthropogenic impact at the landscape scale. The recorded changes in hydrology and salinity that occurred throughout the centuries and millennia would have had profound effects throughout the food web and estuarine ecosystem. Fish populations would have been affected by changes in the food supply due to shifts in runoff affecting turbidity and light penetration in the river. Local vegetation changes within marshes may also have affected juvenile fish populations.