- Lauren Hallett
Lauren Hallett, University of California at Berkeley
Predicting the stability of rangeland productivity to climate change
Increased precipitation variability is predicted to be a consequence of anthropogenic climate change across rangeland systems. As precipitation more frequently departs from the historic range of variability, maintaining stable forage production despite increased climate variability will be a critical management priority in range agroecosystems.
A key mechanism that can lead to stability in forage production is compensatory dynamics, in which different species responses to climate fluctuations result in tradeoffs between functional groups over time. These tradeoffs should buffer overall forage production to climate variability. My dissertation tests the importance of compensatory dynamics for forage stability in an experimental field setting in which I manipulate rainfall availability and species interactions.
- Mallika Nocco
Mallika Nocco, University of Wisconsin
Irrigation and climate impacts to the water-energy balance of the WI Central Sands
Pumping for irrigation in regions with strong ground-surface water connectivity can impact aquatic resources, leading to groundwater governance dilemmas. Recently stressed aquatic resources have created a dilemma between agricultural and aquatic stakeholders in the Wisconsin Central Sands, an ecological region with strong ground-surface water connectivity that has experienced changes in agricultural land use and climate over the past 60 years. My research goal is to determine how agricultural land use and climate change impact the regional water-energy balance of the Wisconsin Central Sands in response to scientific uncertainties identified by stakeholders.
My specific field objectives are to
- Estimate groundwater recharge using METER G3 drain gauges to capture vadose zone flux under potato and maize cropping systems
- Monitor soil water/temperature flux by stratifying METER 5TM sensors from the soil surface to a depth of one meter (top of G3 monolith) under potato and maize cropping systems
- Estimate evapotranspiration (ET) using the METER SC-1 porometer to measure stomatal conductance along with micrometeorology, leaf area index, and gas exchange measurements
Field-generated estimates of groundwater recharge and ET will parameterize and validate a dynamic, agroecosystem model, Agro-IBIS, simulating hydrological responses to climate and land use changes of the past 60 years. The water-energy budgets and water quantity/climate simulations will be shared with stakeholders in the Wisconsin Central Sands and future research questions will be generated through this forum.
- Jens Stevens
Jens Stevens, University of California at Davis
Effects of changing snowpack on invasive plants in montane forests of California
Montane forests are critical ecosystems to understand in the context of climate change because they represent spatial compressions of important climatic gradients and corresponding vegetation in a small geographic area. Decreases in depth and duration of winter snowpack expected in montane forests under climate change might facilitate spread of drought-tolerant invasive plants from lower elevations by lengthening the growing season.
My research investigates whether changes in snowpack can influence the population growth rates of two exotic shrubs (Scotch broom and Spanish broom) in the Sierra Nevada of California. Both species may be sensitive to earlier growing seasons brought about by decreased spring snow cover, because growth may occur via photosynthetically active green stems at soil temperatures as low as 4 °C . However, there is a possible tradeoff between earlier snowmelt and earlier soil moisture depletion that could lead to prolonged drought stress and reduced carbon gain. Preliminary data suggest that the more drought-tolerant shrub, Spanish broom, responds more positively than Scotch broom to reduced winter snowpack.
METER instrumentation will collect a comprehensive record of snow cover and soil moisture across a range of experimental snowpack treatments and forest canopy structures to document the interaction of those two factors and the mechanisms by which they can explain invasive plant performance.
- Whitney Gaches
Whitney Gaches, University of Maryland
Roof-scale modeling of green roof substrate blend on stormwater retention and plant-based water cycling
Green roofs are gaining popularity as stormwater management tools; however, reports concerning green roof performance are primarily based on small-scale platform studies (generally less than 20 square feet). The lack of real-roof performance data can be attributed primarily to expense and logistical concerns (i.e., some roofs are difficult or unsafe to access regularly).
I have established a relationship with a local green roof installation and management company who has been awarded the contract for a large green roof installation for a local government entity. The client wishes to collect data and monitor green roof performance. My project will equip a 30,000 square foot green roof for performance monitoring while simultaneously monitoring identical platform-scale systems for performance using appropriate METER moisture sensors and weather station instruments. Real roof performance data will be compared to platform performance data to determine if small-scale studies accurately predict real roof performance.
- Amanda Cording
Amanda Cording, University of Vermont
Adapting to climate change with Low Impact Development (LID) stormwater management in the Lake Champlain Basin
The goal of this research is to inform future design of Low Impact Development (LID) stormwater bioretention systems to provide optimal residence time, phosphorus adsorption and denitrification in the context of projected increases in precipitation in Vermont as a result of climate change. This research will investigate the mechanisms influencing greenhouse gas emissions and nutrient transformations at various depths in engineered soil media within eight bioretention cells at the newly constructed Outdoor Bioretention Laboratory at the University of Vermont. These systems will also be evaluated for their possible implementation in developing countries, which lack underground stormwater infrastructure.
- Neal Mitchell
Neal Mitchell, University of Illinois at Urbana-Champaign
Forested algific slopes of the driftless area: Soil and microclimate evaluation and monitoring
Algific slopes are naturally occurring microclimatic ecosystems that are distributed across the Driftless Area of the Midwest (Cottrell and Strode 2005). Algific slopes are described as cold-air, north-facing colluvial slopes. Their unique microclimatological properties are due to geologic features fundamental to algific slope formation. Essentially, air is circulated across ice trapped in the fractured geologic substrate, which causes cool moist air to be vented on slopes during the warm months, thus effectively shaping local flora and fauna.
- Scott Pitz
Scott Pitz, Johns Hopkins University
Cryptic methane emissions from upland forests
Methane is the second most important greenhouse gas after CO2 but is far less understood. In the last 10 years, both lab experiments and satellite data have collected evidence that woody plants and forests are emitting methane to the atmosphere. Despite these new findings, upland forests are still considered sinks because organisms in their surface soils consume methane. It is also possible that methane could be leaking out of the deep soil through trees. This could result in a net methane source for an ecosystem that is currently considered a sink. Upland forests cover huge areas of the globe so there is a pressing need to resolve these issues and obtain accurate estimates of fluxes to be integrated into global climate models. Without new and accurate measurements, climate predictions will continue to include systematic flaws.
- Dianne Pater
Dianne Pater, University of California at San Diego
Investigating drought responses in the crop plant Brassica napus
Drought is a major stress that reduces crop yields and will continue to be an increasing problem in the coming years as climate change and limited fresh water supplies lead to higher temperatures, desertification, and increased soil salinity. Abiotic stresses, including drought, elicit production of the plant hormone abscisic acid (ABA), which closes stomata through a complex signaling pathway, reducing the amount of transpirational water loss in plants.
I am using RNAi technology to knock down expression of negative regulator proteins in this pathway to assess whether drought responses in the crop plant Brassica napus (canola) can be enhanced without adversely affecting growth. The transformed plants will be grown under controlled drought conditions, with soil moisture content and stomatal conductance being monitored using METER instrumentation.
- D. Corey Noyes
D. Corey Noyes, Michigan State University
Improving carrot profitability through the integration of slow-release nitrogen fertilizer
Improving nitrogen (N) use efficiency in vegetable production will not only be financially beneficial, but it will also improve environmental quality. In Michigan, carrots are typically grown on very sandy soils and require frequent irrigation and multiple applications of nitrogen fertilizer over the course of their growing season.
My research focuses on optimizing the synchrony of crop-N-demand with N supplied by fertilization through the use of slow-release-nitrogen fertilizer materials (SRN). My overarching hypotheses are that the use of a polymer-coated urea (PCU) SRN material, in Michigan carrot production will
- Allow for fewer top-dress N applications
- Lower total N fertilizer requirements
- Maximize N use efficiency
The potential benefits provided by the use of PCU in this system include reduced input costs, decreased non-renewable resource consumption, and minimization of environmental impacts caused by nitrate leaching. METER data loggers and sensors that measure soil volumetric water content, temperature, and bulk electrical conductivity will help improve our understanding of conditions that regulate the release of N from the PCU.
Using METER data in combination with N extractions from soil samples, we hope to model N release as a function of moisture and temperature and to quantify the relationship between electrical conductivity and N release. This information will be helpful for designing nutrient management programs for vegetable growers that are both profitable and environmentally friendly.