John Wesley Powell Center for Analysis and Synthesis

Land Resources

Powell Center working groups rarely are just one USGS Mission Area and are sorted into these areas by the groups themselves. Projects may be relevant to additional areas.

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Filter Total Items: 26
Date published: August 13, 2019
Status: Active

Visualizing the Invisible: Causes, Consequences, Changes, and Management of Streamflow Depletion Across the U.S.

Streamflow is declining in many parts of the United States (US) due to factors including groundwater pumping, land use change, and climate change. Streamflow depletion, a reduction in groundwater discharge to a stream due to human activities such as pumping and/or land use change, tends to evolve slowly and can be entirely invisible for many years to decades. This is because streamflow...

Date published: June 5, 2018
Status: Active

Wetland fluxnet synthesis for methane: understanding and predicting methane fluxes at daily to interannual timescales

Wetlands provide many important ecosystem services, including wildlife habitat, water purification, flood protection, and carbon metabolism. Our ability to manage these services and predict the long-term health of wetlands is strongly linked to their carbon fluxes, of which methane (CH4) is a key component. Natural wetlands emit approximately 30% of global CH4 emissions, as their waterlogged...

Date published: June 5, 2018
Status: Active

Novel multi‐scale synthesis of nitrogen fixation rates and drivers across the terrestrial biosphere

Biological nitrogen fixation (BNF) is a critical biogeochemical process that converts inert atmospheric N2 gas into biologically usable forms of the essential nutrient nitrogen. A variety of free-living and symbiotic organisms carry out BNF, and in most regions worldwide, BNF is the largest source of nitrogen that fuels terrestrial ecosystems. As a result, BNF has far reaching effects on...

Date published: October 1, 2017
Status: Active

A global synthesis of land-surface fluxes under natural and human-altered watersheds using the Budyko framework

Global hydroclimatic conditions have been significantly altered, over the past century, by anthropogenic influences that arise from warming global climate and also from local/regional anthropogenic disturbances. There has been never been an effort that has systematically analyzed how the spatio-temporal variability of land-surface fluxes vary in natural and human-altered watersheds globally....

Date published: October 1, 2016
Status: Active

Accounting for U.S. ecosystem services at national and subnational scales

Ecosystem services - the benefits that nature provides to society and the economy - are gaining increasing traction worldwide as governments and the private sector use them to monitor integrated environmental and economic trends. When they are well understood and managed, ecosystems can provide these long-term benefits to people - such as clean air and water, flood control, crop pollination,...

Date published: August 19, 2015
Status: Active

What lies below? Improving quantification and prediction of soil carbon storage, stability, and susceptibility to disturbance.

Soils are a vast reservoir of organic carbon (C), rendering the fate of soil C an important control on the global climate system. Widespread changes in soil C storage capacity present a potentially strong feedback to global change. Yet, a comprehensive understanding of how soil C will respond to climate and/or land use disturbance remains illusive, resulting in major uncertainties in global...

Contacts: Corey Lawrence
Date published: October 6, 2014
Status: Active

Characterizing landscape genomics and reconstructing pathways to plant ecological specialization and speciation

This proposal brings together biologists and geoscientists to evaluate the evolution of stress tolerance and adaptation to extreme environments in plants. Stress tolerance has been studied mainly from a physiological perspective using laboratory and field experiments. In contrast, this project will take a combined environmental and evolutionary perspective using national public databases and a...

Date published: October 25, 2013
Status: Active

Elucidating mechanisms underlying amphibian declines in North America using hierarchical spatial models

Amphibian populations are declining globally at unprecedented rates but statistically rigorous identification of mechanisms is lacking. Identification of reasons underlying large-scale declines is imperative to plan and implement effective conservation efforts. Most research on amphibian population decline has focused on local populations and local factors. However, the ubiquity of declines...

Date published: October 25, 2013
Status: Active

Broader view of North American climate over the past two millennia: Synthesizing paleoclimate records from diverse archives

Regional- to continental-scale paleoclimate syntheses of temperature and hydroclimate in North America are essential for understanding long-term spatiotemporal variability in climate, and for properly assessing risk on decadal and longer timescales. However, existing syntheses rely almost exclusively on tree-ring records, which are known to underestimate low-frequency variability and rarely...

Date published: October 22, 2013
Status: Active

Forecasting forest response to N deposition: integrating data from individual plant responses to soil chemistry with a continental-scale gradient analysis

Nitrogen deposition is altering forest dynamics, terrestrial carbon storage, and biodiversity. However, our ability to forecast how different tree species will respond to N deposition, especially key response thresholds, is limited by a lack of synthesis across spatial scales and research approaches. To develop our best understanding of N deposition impact on tree growth and survival, we will...

Date published: October 22, 2013
Status: Active

Integrating modeling and empirical approaches to improve predictions of tropical forest responses to global warming

Tropical forests contain > 50% of the world’s known species (Heywood 1995), 55% of global forest biomass (Pan et al. 2011), and exchange more carbon (C), water and energy with the atmosphere than any other ecosystem type (e.g., Saugier et al. 2001). Despite their importance, there is more uncertainty associated with predictions of how tropical forests will respond to warming than for any...

Date published: October 22, 2013
Status: Active

Potential Impacts of Prospective Climate Change on Groundwater Recharge in the Western United States

Groundwater withdrawals in the western US are a critical component of the water resources strategy for the region. Climate change already may be substantially altering recharge into groundwater systems; however, the quantity and direction (increase or decrease) of changes are relatively unknown as most climate change assessments have focused on surface water systems. We propose to conduct a...