PS 22-1 - Exploring the potential drivers of below and above-ground biomass and productivity across montane meadow ecotypes

Tuesday, August 16, 2022

5:00 PM – 6:30 PM EDT

Located in: ESA Exhibit Hall

Presenting Author(s)

AB

April E. Bermudez

Rocky Mountain Biological Laboratory, Crested Butte, CO
Ann Arbor, Michigan, United States

Coauthor(s)

JD

John D. Den Uyl

Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI
Ann Arbor, Michigan, United States
BI

Brian D. Inouye, PhD

Florida State University
Tallahassee, Florida, United States
DI

David W. Inouye, PhD

RMBL, United States
RI

Rebecca E. Irwin

North Carolina State University, United States
NU

Nora Underwood

Department of Biological Science, Florida State University
Tallahassee, FL, United States
AC

Aimee T. Classen, PhD

University of Michigan
Ann Arbor, Michigan, United States

Background/Question/Methods

Roots, and their traits, are important in regulating below-ground ecosystem processes through biomass production, nutrient cycling, and plant-soil interactions. However, when measuring a plant community's response to changes in the environment, roots are often ignored. Thus, the question remains: does root productivity and phenology respond to seasonal and interannual environmental drivers similarly to above-ground productivity and phenology? Here, we explored if below-ground and above-ground productivity and biomass showed similar seasonal patterns in root-shoot productivity and biomass. Over two growing seasons, we measured root dynamics by installing in-situ minirhizotrons to digitally monitor root growth in three different meadow ecotypes at the Rocky Mountain Biological Laboratory (RMBL). Using the digitized root images, we calculated root production, standing stock at weekly intervals from snowmelt in the spring to snowfall in the late fall. We analyzed flower abundance, vegetation greenness (NDVI), and abiotic data (e.g. temperature and soil moisture) from long-term plant phenology monitoring to investigate how above-ground conditions relate to below-ground measurements. We hypothesized that there would be a difference in timing for root and shoot productivity as allocation of tissue growth might be dependent on resource availability and abiotic conditions in dry and wet meadows across the growing seasons.

Results/Conclusions

Overall and across ecotypes, aboveground productivity peaked at the height of the growing season (Mid-June), whereas root productivity peaked early in the fall. Below-ground standing stock varied over time, but was similar across the three meadow types (Veratrum Meadow, Willow Interface, and Wet Meadow) and among soil depths (0cm, 10cm, and 20cm). Standing stock gradually increased overtime for all meadow types at depths 0cm to 20cm; whereas it decreased in late August at 20 to 30cm. The veratrum meadow had, between 8-37% more standing crop than the Willow Interface meadow and the Wet Meadow. Across all meadow types, root productivity was highest in the late spring. However, roots had a second peak in productivity that differed among the meadow types – the Veratrum meadow in September, the Willow Interface meadow in early August and the Wet meadow in mid-August. The differences in phenological timing of rooting events across meadow types highlights the importance of exploring the potential drivers of root production.