Becklin MONet Request
EMSL Project ID
60940
Abstract
Climate change is altering the timing of important developmental events, such as when plants emerge, flower, and senesce during the growing season. These phenological events determine the timing of peak plant productivity which can scale to influence carbon fluxes and inputs into the soil. Most plant phenological studies have focused on aboveground traits that are easy to observe. However, belowground phenology, especially the timing of root and microbial activity, likely plays a pivotal role in determining overall carbon dynamics and responses to climate change.
Warming temperatures typically cause accelerated plant phenology. This may only be possible if the activity of soil microbes involved in decomposition, nutrient cycling, and nutrient uptake is also accelerated, resulting in a flux of nutrients to support earlier plant growth under warmer conditions. However, soils are somewhat buffered from temperature fluctuations, especially in snow-covered ecosystems, which could lead to asynchronous responses between above- and belowground organisms. In these systems, stimulation of root exudation by perennial plants following snowmelt may be an important mechanism driving accelerated soil microbial activity and leading to positive feedbacks on plant growth and development.
Phenological responses to climate change likely vary across plant populations due to differences in historical climate conditions that have selected for different plant traits, environmental factors (e.g., soil moisture, nutrients) that constrain organismal responses to temperature, and shifts in microbial community composition that affect key soil processes and plant-microbe interactions. The proposed study will leverage populations of Ligusticum porteri, a common subalpine plant species in the Rocky Mountains. Twenty populations distributed across a natural climate gradient have been studied as part of a long-term project on flowering phenology and plant-insect interactions. These populations vary in their aboveground phenological sensitivity to snowmelt date. We hypothesize that the timing of root and microbial activity after snowmelt contributes to variable phenological responses in this system.
To test this hypothesis and assess alignment between above- and belowground phenology we will combine surveys of aboveground traits (emergence, flowering, senescence) and plant productivity with detailed molecular and chemical measures of soil functional traits as outlined in the Molecular Observation Network protocol. Initial studies will focus on three L. porteri populations that differ in the timing of snowmelt and average summer temperature. We will sample two locations at each population at three time points: immediately after snowmelt, start of flowering, and senescence. Temporal sampling within multiple populations will be essential to quantifying variation in above- and belowground phenology, a necessary parameter for modeling climate responses, and for characterizing microbial mechanisms driving these responses. Future projects will expand sampling to include additional populations from the long-term study.
In summary, this work will allow us to (1) assess the alignment of responses to snowmelt between above- and belowground phenology, (2) quantify variation in phenological responses among populations across a snowmelt gradient, and (3) link phenological responses to microbial functions involved in soil carbon and nutrient cycling.
Project Details
Project type
MONet
Start Date
2023-07-05
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Team Members