Miriam C. Jones
Jay R. Alder
David Fastovich
Kristen Hoefke
Robert Poirier
Fred C. Wurster
Debra A. Willard
2023
<div id="abstracts" class="Abstracts u-font-gulliver text-s"><div id="abs0010" class="abstract author" lang="en"><div id="abssec0010"><p id="abspara0010">The Great Dismal Swamp wetland, spanning >400 km<sup>2</sup><span> along the Virginia and North Carolina border, was shaped by a complex combination of geomorphic, climatic, and anthropogenic forcings during the last 14,000 years. Pollen, macrofossils, charcoal, and physical properties from sediment cores at seven sites provide a detailed record of the spatial heterogeneity of the wetland and the roles played by natural hydrologic variability, wildfire, and human modification of drainage in shaping vegetation and habitats. Cold-temperate forests occupied regional uplands from at least 13.5–10.3 cal ka BP. Marshes dominated by grasses and other herbaceous taxa began developing along low-elevation streams as early as 10.3 cal ka BP, resulting in accumulation of organic silts. Long-hydroperiod, peat accumulating marshes, with abundant floating aquatic plants, developed as early as 9.6 cal ka BP, as rapid rates of sea-level rise elevated the water table and facilitated wetland development and peat accumulation along stream courses. By the mid-Holocene (c. 7–6.5 cal ka BP), when local sea-level rise began slowing and reached about 12–15 m below present, shorter hydroperiod, peat-accumulating marshes dominated the landscape, with increased wildfire activity. Great Dismal Swamp vegetation shifted from marshes to peat-accumulating forested wetlands by c. 3.7 cal ka BP; these were dominated by varying combinations of </span><i>Nyssa</i><span> </span>(tupelo),<span> </span><i>Taxodium</i><span> </span>(cypress), and<span> </span><i>Chamaecyparis thyoides</i><span> </span>(Atlantic white cedar). Wildfires were infrequent during this time, and the forested wetlands persisted, with minor compositional changes related to climate-driven fluctuations in stream flow, until colonial ditching and logging began in the swamp during the late 18th century. These activities decreased cypress and cedar populations, and, by the mid-20th century, expanded ditching resulted in even drier conditions and expansion of maple-gum (dominated by<span> </span><i>Acer</i><span> </span>and<span> </span><i>Liquidambar</i>)<i>,</i><span> </span>and pine-pocosin (dominated<span> </span><i>by Pinus</i><span>) forests. The distribution of these forests differs from that of the late Holocene and represents a fundamental shift in hydrology, peat structure, vegetation, and fire regime due to landscape alterations of the last few centuries.</span></p></div></div></div>
application/pdf
10.1016/j.quascirev.2023.108153
en
Elsevier
Roles of climatic and anthropogenic factors in shaping Holocene vegetation and fire regimes in Great Dismal Swamp, eastern USA
article