Associate Professor Michigan State University, United States
Temperature is a main factor controlling the timing of plant phenological events and it has been well documented that warming temperatures due to climate change are shifting these events. However, what is less understood is how, or to what extent, the soil microbiome affects plant phenology, let alone how climate stressors influence these interactions.
Here we used open-top chambers in a long-term warming experiment at Kellogg Biological Station’s Long Term Ecological Research site to characterize early successional soil microbial and plant communities' responses to warming. Soil samples were taken throughout the growing season in warming and ambient plots. To characterize the soil microbiome, DNA was extracted to sequence 16S and ITS rRNA gene amplicons in order to characterize bacteria and fungi community structure. Green-up, flowering, seed-set and productivity was recorded every 3 days from beginning of green-up to senescence. In addition, a plant-soil feedback (PSF) experiment measured the effect of warmed vs. ambient field conditioned soil microbiomes on individual species’ growth rate and biomass. Using these experiments, we asked: 1) How does warming affect phenology in different species? and 2) Does the soil microbiome mediate plant growth and phenological response(s) to climate stressors?
Results for the long-term warming experiment show that 7 years of warming had an effect on the median date of flowering with warmed plots experiencing a median date of flowering on average 3.8 days earlier than ambient plots. Furthermore, the PSF experiment showed that Trifolium pratense grown in pots inoculated with warmed soil had more biomass than those in the ambient soils. The difference in biomass hints to a microbial community difference within the soil, which I am currently characterizing, and this difference is likely influencing phenology timing alongside warmer temperatures. We expect that the soil microbiome composition will explain responses to climate stressors through ameliorating plant development and defense against various climate stressors. This research will inform how microbial community composition can be used to predict the phenological responses of species and ecological communities to global change.