Focus on “deep soil column” S patial patterns M echanism that control development and function

1. Focus on “deep soil column” • Spatial patterns • Mechanism that control development and function • Implications for ecology, biogeochemistry and hydrology • What are spatial (elevation, local topography) patterns of “deep soil”? - link back to process –based model of regolith dev (teaser), • How quickly can it form (weathering, fracture, etc)? • How do fast biogeophysics work (root depth, water movement)? • How does it control production, vegetation, biogeochemistry, soil carbon flux? • How does it control hydrology? • How will it control/limit/modify effects of climate change on montane hydrology, biogeochem/ecology? • How will it influence the effects of forest management on hydrology, forest vulnerability to drought… • What is the role of lateral transport of water, dissolved and particulate material on spatial patterns • Makes use of most people’s expertise • Important and poorly understood. Builds on round 1 – shows we’re learning . “Made great progress and will now focus on the next key unknown” • Clearly fits CZO scope/vision • Good experimental design essential

2. Change this and add elevation gradient

3. Tague and Dugger (2010) Ecohydrology and Climate Change in the Mountains of the Western USA – A Review of Research and Opportunities. Geography Compass 4(11): 1648-1663

4. CZO-Report- Tague Challenge 1. All sites need to expand development of integrated, comprehensive, and to the extent possible, quantitative conceptual models of how the critical zone functions and evolves at their location. Challenge 3. Sites need to explicitly expand their focus to include observing, modeling, predicting, and explaining environmental change on societally relevant timescales (decadal to centurial). Include the following Qs How are the volumes, timing, and quality of streamflow due to changing climate and land use likely to change in the future? What critical zone processes are responsible for these changes, where are the changes likely to be most pronounced, and what landscapes are relatively insensitive to change? What controls the development of water stress in vegetation? How does the basic architecture of the critical zone affect the temporal and spatial dimensions of plant-available water, and how will changing climate and land use affect water stress in the future. Under what circumstances does water stress lead to cascading disturbances of drought, fire, mortality, etc?

5. Tague2-Broader context of climate change in snow-dominated regions: Focus on mountainous Western US - Forests and Water? Water for forests What happens to water availability (supply) for andwater use (demand) by forests in a warming climate? How do changes in supply and demand impact forest productivity and sensitivity to disturbance (fire, disease, drought related dieback)? Do these changes have implications for streamflow timing and magnitude? Water for us and for fish

6. Conclusions - Hart • Our results suggest that climatic warming in snow-dominated ecosystems of the Sierra will increase net greenhouse gas emission from the soil to the atmosphere in the short-term. • However, continued advancement of the snowmelt date, without a simultaneous increase in precipitation, will likely constrain the extent of the temperature-induced increase in greenhouse gas fluxes. Other Directions: • Rates and ‘leakiness’ of nitrogen cycling • Microbial population sizes (e.g., total biomass, methane oxidizers, nitrifiers, denitrifiers) • Mechanisms for C release with warming and C sequestration with drying • Scale up snowmelt treatments to larger areas to include plant responses and plant-soil interactions • What exactly is going on during winter?

7. Hopmans - CZO Renewal • Deep soil monitoring and characterization (include soil weathering, O’Geen) • Tree canopy (temperature/radiation) & tree root zone measurements (isotopes) • Inverse modeling of tree hydraulics - mechanistic response of tree to changes in atmospheric forcing (by climatic changes) • Upscaling single tree to forested watershed • Across Western CZO’s studies (graduate students)