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Harvard Forest REU Symposium Abstract 2019

  • Title: Understanding the impacts of historical land use change through sediment core analysis: Center Pond, Vermont
  • Author: Turtle Mccloskey-Potter (Southern Oregon University)
  • Abstract:

    The post glacial lakes of New England can provide records of how land use changes have influenced biogeochemical processes through the analysis of lacustrine sediment deposits. This project investigates the sensitivity of the Center Pond watershed in northern Vermont to disturbances associated with land use changes resulting from Euro-American settlement in the 18th and 19th centuries. This research provides insightful information regarding how New England watersheds respond to anthropogenic disturbances. Radiocarbon dates were used to create a geochronology for the cores spanning nearly 2500 years, and changes in the productivity and biogeochemistry of the Center Pond watershed were analyzed across this record to assess the impacts of land use change. Increases in carbon-nitrogen ratios (C:N) and iron-manganese ratios (Fe:Mn) in cores after approximately 1800 suggest environmental disturbances in the watershed, likely related to land clearing by Euro-American settlers. However, a clear increase in erosion as a result of these disturbances is not obvious; clastic sediment layers in cores occur during a period of decreasing human disturbance as revealed by Geographic Information Systems (GIS) analysis. Historical aerial photos indicate a decrease in cleared land from 18.25% in 1942 to 1.67% in 2016. Discrete clastic deposits during this period may correlate to historical floods. Despite a significant decrease in the intensity of anthropogenic disturbances and the widespread reforestation of the region, it appears that the lake has not returned to its pre-disturbance state.

  • Research Category: Historical and Retrospective Studies; Soil Carbon and Nitrogen Dynamics