PS 58-93 - Effects of invasive Amur Honeysuckle (Lonicera maackii) on belowground soil CO2 emissions

Thursday, August 15, 2019
Exhibit Hall, Kentucky International Convention Center
Aidan G. Shumaker1, Allie S. Niemeyer2, Stefani P. Schmocker1 and Laurel J. Anderson1, (1)Department of Botany and Microbiology, Ohio Wesleyan University, Delaware, OH, (2)Department of Zoology, Ohio Wesleyan University, Delaware, OH
Background/Question/Methods

Amur honeysuckle (Lonicera maackii) is an invasive woody plant found throughout the deciduous forests of the eastern United States, and is taking over habitats of native shrubs such as spicebush (Lindera benzoin). L. maackii has unique traits compared to natives, showing earlier leaf-out and later leaf senescence, higher leaf nitrogen levels and faster leaf decomposition. L. maackii may also alter soil conditions through late and early season root activity and litter quality impacts on microbes. Previous research has shown that microbial respiration in soils under invasive plants can be significantly altered compared to soils under native species, suggesting that soil greenhouse gas emissions may change with invasion. However, we know relatively little about the effects of L. maackii on soil respiration. We used a LI-COR LI-6400 to measure soil CO2 efflux on a monthly basis under 12 individual shrubs in a temperate deciduous forest in Ohio using PVC collars embedded in the soil. These measurements were compared with soil efflux data collected from beneath 12 native L. benzoin shrubs and in 12 patches of soil at least one meter away from the canopy dripline of any shrub.

Results/Conclusions

Soil respiration measurements collected from June 2018 to November 2018 showed no significant differences in CO2 emissions among the three soil locations (repeated measures ANOVA, p > 0.05). During the summer, it may be that high and similar productivity of both native and invasive plants during this season is reflected in similar belowground respiration levels. During the winter and fall seasons, soil respiration and plant root activity is limited in all sites by the low temperatures. In April 2019, when L. maackii had begun leaf out while L. benzoin had not, CO2 fluxes were significantly higher under L. maackii as compared to L. benzoin. Fluxes were also higher under L. maackii as compared to sites away from shrubs but the differences were not significant. Therefore, it seems that differences in aboveground plant activity may also be expressed belowground, although the relative contributions of heterotrophic vs. autotrophic respiration in these patterns is uncertain. Data comparing root density in the rings will be collected after one year of respiration measurements to determine if respiration rates are positively correlated with high root densities.