Work at the SPA Lab bridges multiple scientific disciplines to advance basic understanding and solve problems of ecological and societal significance. Our current projects can be divided in three main areas:
1- Understanding the impact of past environmental change on the distribution and function of modern ecosystems
The pursuit of solutions for current global challenges is in many ways synonymous with the search for historical knowledge to support theoretical and practical inquiry into sustainability. Every system that has persisted through time acquired some degree of resilience to environmental change. We use archives of past environmental conditions, such as tree ring cellulose, soil organic matter, and speleothem carbonates, combined with measurements of stable isotopes, elemental analyses, and radiometric dating to elucidate how environmental change has impacted terrestrial systems before and after humans became a dominant planetary force. For example, our current NSF-funded research focuses on describing the influence of climate variability over thousands of years on the distribution of modern tropical forest and savanna biomes, providing critical information for understanding the forces that shaped ancient and contemporary societies.
2- Quantifying the impact of changes in atmospheric composition on natural and human-engineered ecosystems
Since the industrial revolution, the human influence on the global environment has become so large that a case has been made for a new geological epoch: the Anthropocene. Using observation and experimental datasets, which integrate ecophysiological and biogeochemical methods, we investigate the impacts of rising carbon dioxide levels, nitrogen deposition and shifting soil quality on the performance of individual species of interest in agriculture and forestry as well as on the distribution and functioning of whole ecosystems. For example, in our recently completed projects long-term data from natural ecosystems served as a baseline to predict responses in productivity, water and nutrient use in ecosystems that are managed for energy and food production.
3- Developing management and restoration strategies to mitigate environmental change and optimize the use of natural resources
We study how complex soil-plant-atmosphere interactions that control concerted changes in carbon, water, and nutrient cycles on land can be harnessed to provide solutions for environmental challenges. For example, our current NSF-funded projects combine information needed to design conservation, management, and restoration efforts to improve the use of natural resources and the sustainability of managed and unmanaged prairies across the Pacific Northwest. Other recent projects tested new scaling principles to predict water-use efficiency in tree plantations, restore biodiversity in mined areas in the Brazilian Amazon/Cerrado transition, and promote carbon sequestration in degraded subsiding wetlands in California. Using baseline data from natural systems, we evaluate how managed forests, agricultural fields, and bioenergy crops can be used to enhance ecosystem services and perhaps promote climate stability.
National Science Foundation: Delineating Holocene climate-biosphere links from climate and vegetation reconstructions from the Amazon region
National Science Foundation: Harnessing biological complexity to improve food security
National Geographic The climate paradox: mapping resilience and vulnerability of montane forests across the Pacific Northwest
Save-the-Redwoods League: Understanding the influence of an apex predator on the forest carbon cycle
Water Sustainability and Climate (WSC) USDA-NIFA: Agricultural sensitivity to climate change and water resources interactions in the San Joaquin Valley California and system resilience offered by adaptation strategies
Recently completed grants
American Carbon Registry: Restoration of California Deltaic and Coastal Wetlands for Climate Change Mitigation
California Department of Food and Agriculture: Isotopic records of evapotranspiration, water balance, and depth of water uptake in California’s tree crops
University of California Innovative Development: Retracing drought impacts in California: A new approach to measure changes in food quality and productivity as caused by fluctuations in rainfall
UC MEXUS-CONACYT: Effects of soil-plant feedbacks on the response of forest ecosystems to climate variability and nitrogen deposition
Chinese Academy of Science: Climate-driven vegetation dynamics across altitudinal gradients in the Qinghai-Tibetan Plateau, China
Brazilian Council for Scientific and Technological Development: Ecological implications of large scale restoration of degraded land in the Cerrado-Amazon transition
We work collaboratively across biomes to understand causes and mitigate consequences of ecosystem transformations. The map below displays the location of scientists who co-authored peer-reviewed articles with professor Lucas Silva’s (SPA Lab – Principal Investigator). Source: ISI Web of Science.