Response of black ash wetland gaseous soil carbon fluxes to a simulated emerald ash borer infestation

Abstract

The rapid and extensive expansion of emerald ash borer (EAB) in North America since 2002 may eliminate most existing ash stands, likely affecting critical ecosystem services associated with water and carbon cycling. To our knowledge, no studies have evaluated the coupled response of black ash (Fraxinus nigra Marsh.) wetland water tables, soil temperatures, and soil gas fluxes to an EAB infestation. Water table position, soil temperature, and soil CO₂ and CH₄ fluxes were monitored in nine depressional headwater black ash wetlands in northern Michigan. An EAB disturbance was simulated by girdling (girdle) or felling (ash-cut) all black ash trees with diameters greater than 2.5 cm within treated wetlands (n = 3 per treatment). Soil gas fluxes were sensitive to water table position, temperature, and disturbance. Soil CO₂ fluxes were significantly higher, and high soil CH₄ fluxes occurred more frequently in disturbed sites. Soil CH₄ fluxes in ash-cut were marginally significantly higher than girdle during post-treatment, yet both were similar to control sites. The strong connection between depressional black ash wetland study sites and groundwater likely buffered the magnitude of disturbance-related impact on water tables and carbon cycling.

Keywords

forested wetlands, Fraxinus nigra, invasive pest disturbance, greenhouse gas fluxes, soil carbon, biogeosciences, EAB

Citation

Van Grinsven, Matthew; Shannon, Joseph; Bolton, Nicholas; Davis, Joshua; Noh, Nam; Wagenbrenner, Joseph; Kolka, Randall; Pypker, Thomas. 2018. Response of black ash wetland gaseous soil carbon fluxes to a simulated emerald ash borer infestation. Forests. 9(6): 324. https://doi.org/10.3390/f9060324.