Project Funding: 2012 - 2015

NRA: 2011 NASA: Terrestrial Ecology   

Funded by NSF, NASA

Abstract:
Cycles of carbon (C), nitrogen (N) and water in terrestrial ecosystems are tightly coupled through a shared set of biophysical processes. The N status of plants is a key control on C assimilation, and both affect water fluxes from land to atmosphere. In turn, water availability is one of the most important controls on plant growth globally and can set an upper bound on the availability of N. How ecosystems respond to changes in the availability of water and its temporal variability will likely be among the most important effects of climate change and one of the most challenging for models to capture. Recent analyses have demonstrated significant, broad-scale relationships between canopy %N and both whole-canopy photosynthesis and shortwave canopy albedo. These results stem from the constraints imposed by acquisition of multiple resources, which drive plants toward functional convergence among a variety of leaf and canopy level traits. The resulting patterns suggest a greater degree of coupling between C, N and energy balances than has previously been considered and provide a basis for using canopy spectral data to improve understanding of ecosystem-climate interactions. To date, efforts to develop similar scaling approaches for plant water use and water use efficiency (WUE) have lagged, despite abundant evidence suggesting strong relationships between WUE and plant C and N status. Contributing factors include: (1) incongruency of the spatial and temporal scales at which ET and WUE are derived, (2) incomplete understanding of the mechanisms driving WUE across species and ecosystems, (3) the challenge of relating species-level measurements to water fluxes over diverse canopies, and (4) a scarcity of analysis that have considered WUE in relation to plant traits and plant functional types across space and time. Based on results from our prior NASA-funded research, combined with documented relationships between C and water cycles, the objectives of the proposed work are to examine how evapotranspiration (ET) and WUE in forests relate to variation in foliar N and canopy photosynthesis and to use the resulting information to improve a model of ecosystem C, N and H2O cycles. We also propose that the vulnerability of ecosystems to altered precipitation amount and variability is influenced by the N status of vegetation and by the diversity of species present. We plan to achieve these goals through the following objectives: 1. Build on a previous, NASA-supported analysis of hyperspectral remote sensing and C flux data to determine how ET and WUE relate to canopy nitrogen, carbon assimilation and albedo in North American ecosystems. 2. Examine the degree to which WUE and its relation with N availability over space and time can be estimated using 13C, 18O and 15N isotope measurements in leaf and woody tissues. 3. Examine the degree to which ecosystem response to climate variability is influenced by species diversity and the N status of species present. 4. Evaluate canopy spectral properties related to WUE, canopy water content and species diversity using high spectral resolution aircraft remote sensing. This will be repeated after degrading imaging spectrometer spatial resolution to 60 m in order to evaluate future applications using HyspIRI. 5. Integrate results from objectives 1-4 to determine how WUE varies with C, N and energy fluxes, along with canopy reflectance, and use the results to improve a continental upscaling analysis of C fluxes, ET and WUE. 6. Use results from objective 5 to constrain parameters in a widely used ecosystem model and run the model forward to evaluate changes in C-N-H2O interactions under scenarios of future climate and altered biodiversity.

Publications:

Guerrieri, R., Belmecheri, S., Ollinger, S. V., Asbjornsen, H., Jennings, K., Xiao, J., Stocker, B. D., Martin, M., Hollinger, D. Y., Bracho-Garrillo, R., Clark, K., Dore, S., Kolb, T., Munger, J. W., Novick, K., Richardson, A. D. 2019. Disentangling the role of photosynthesis and stomatal conductance on rising forest water-use efficiency. Proceedings of the National Academy of Sciences. 116(34), 16909-16914. DOI: 10.1073/pnas.1905912116

Guerrieri, R., Lepine, L., Asbjornsen, H., Xiao, J., Ollinger, S. V. 2016. Evapotranspiration and water use efficiency in relation to climate and canopy nitrogen in U.S. forests. Journal of Geophysical Research: Biogeosciences. 121(10), 2610-2629. DOI: 10.1002/2016jg003415

Lepine, L. C., Ollinger, S. V., Ouimette, A. P., Martin, M. E. 2016. Examining spectral reflectance features related to foliar nitrogen in forests: Implications for broad-scale nitrogen mapping. Remote Sensing of Environment. 173, 174-186. DOI: 10.1016/j.rse.2015.11.028

Burakowski, E. A., Ollinger, S. V., Bonan, G. B., Wake, C. P., Dibb, J. E., Hollinger, D. Y. 2016. Evaluating the Climate Effects of Reforestation in New England Using a Weather Research and Forecasting (WRF) Model Multiphysics Ensemble. Journal of Climate. 29(14), 5141-5156. DOI: 10.1175/JCLI-D-15-0286.1

Pellissier, P. A., Ollinger, S. V., Lepine, L. C., Palace, M. W., McDowell, W. H. 2015. Remote sensing of foliar nitrogen in cultivated grasslands of human dominated landscapes. Remote Sensing of Environment. 167, 88-97. DOI: 10.1016/j.rse.2015.06.009

Thorn, A. M., Xiao, J., Ollinger, S. V. 2015. Generalization and evaluation of the process-based forest ecosystem model PnET-CN for other biomes. Ecosphere. 6(3), art43. DOI: 10.1890/ES14-00542.1

Burakowski, E. A., Ollinger, S. V., Lepine, L., Schaaf, C. B., Wang, Z., Dibb, J. E., Hollinger, D. Y., Kim, J., Erb, A., Martin, M. 2015. Spatial scaling of reflectance and surface albedo over a mixed-use, temperate forest landscape during snow-covered periods. Remote Sensing of Environment. 158, 465-477. DOI: 10.1016/j.rse.2014.11.023

Sun, S., Sun, G., Caldwell, P., McNulty, S. G., Cohen, E., Xiao, J., Zhang, Y. 2015. Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part I evaluation of a water and carbon balance model. Forest Ecology and Management. 353, 260-268. DOI: 10.1016/j.foreco.2015.03.054

Sun, S., Sun, G., Caldwell, P., McNulty, S., Cohen, E., Xiao, J., Zhang, Y. 2015. Drought impacts on ecosystem functions of the U.S. National Forests and Grasslands: Part II assessment results and management implications. Forest Ecology and Management. 353, 269-279. DOI: 10.1016/j.foreco.2015.04.002

Xue, B., Guo, Q., Otto, A., Xiao, J., Tao, S., Li, L. 2015. Global patterns, trends, and drivers of water use efficiency from 2000 to 2013. Ecosphere. 6(10), art174. DOI: 10.1890/ES14-00416.1

Xiao, J., Ollinger, S. V., Frolking, S., Hurtt, G. C., Hollinger, D. Y., Davis, K. J., Pan, Y., Zhang, X., Deng, F., Chen, J., Baldocchi, D. D., Law, B. E., Arain, M. A., Desai, A. R., Richardson, A. D., Sun, G., Amiro, B., Margolis, H., Gu, L., Scott, R. L., Blanken, P. D., Suyker, A. E. 2014. Data-driven diagnostics of terrestrial carbon dynamics over North America. Agricultural and Forest Meteorology. 197, 142-157. DOI: 10.1016/j.agrformet.2014.06.013

Wang, W., Xiao, J., Ollinger, S. V., Desai, A. R., Chen, J., Noormets, A. 2014. Quantifying the effects of harvesting on carbon fluxes and stocks in northern temperate forests. Biogeosciences. 11(23), 6667-6682. DOI: 10.5194/bg-11-6667-2014

Green, M. B., Bailey, A. S., Bailey, S. W., Battles, J. J., Campbell, J. L., Driscoll, C. T., Fahey, T. J., Lepine, L. C., Likens, G. E., Ollinger, S. V., Schaberg, P. G. 2013. Reply to Smith and Shortle: Lacking evidence of hydraulic efficiency changes. Proceedings of the National Academy of Sciences. 110(40). DOI: 10.1073/pnas.1312130110

Ollinger, S. V., Reich, P. B., Frolking, S., Lepine, L. C., Hollinger, D. Y., Richardson, A. D. 2013. Nitrogen cycling, forest canopy reflectance, and emergent properties of ecosystems. Proceedings of the National Academy of Sciences. 110(27). DOI: 10.1073/pnas.1304176110

Green, M. B., Bailey, A. S., Bailey, S. W., Battles, J. J., Campbell, J. L., Driscoll, C. T., Fahey, T. J., Lepine, L. C., Likens, G. E., Ollinger, S. V., Schaberg, P. G. 2013. Decreased water flowing from a forest amended with calcium silicate. Proceedings of the National Academy of Sciences. 110(15), 5999-6003. DOI: 10.1073/pnas.1302445110

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Canopy diversity in relation to carbon fluxes, water use and ecosystem resilience in North American forests.   --   (Scott Ollinger, Jingfeng Xiao, Rossella Guerrieri, Lucie Lepine, Heidi Asbjornsen)   [abstract]
• Linking carbon and water cycling to nitrogen for forests across North America: From the leaf to the ecosystem   --   (Rossella Guerrieri, Lucie C. Lepine, Heidi Asbjornsen, Jingfeng Xiao, Scott Ollinger)   [abstract]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• North American Carbon Program (NACP) Project Profile