Project Funding: 2014 - 2017

NRA: 2012 NASA: Interdisciplinary Research in Earth Science   

Funded by NASA

Abstract:
Tropical forests are critical drivers of atmospheric and terrestrial energy, carbon, water, and nutrient dynamics on a global scale and large-scale changes to tropical forests will have cascading effects on global circulation models. Most climate scenarios predict that tropical forests will experience reduced precipitation, in addition to rising temperatures, and the response to these projected increases in drought frequency and intensity remains highly uncertain. For the largest continuous tropical forest, Amazonia (5.5 million km2), there is still no consensus on the overall forest response to the recent 2005 and 2010 Amazon mega-droughts. Still debatable is whether or not tropical forests green-up and exhibit resilience to dry season drought, and whether resilience or vulnerability to drought is persistent through time. Also at question is whether the recently observed increases in extreme drought frequency are signs of an approaching “tipping point”, at which the tropical forests are projected to convert to savanna. Anticipating the consequences of projected changes in precipitation regimes of tropical forests requires additional information to be compared alongside remotely sensed data. We propose interdisciplinary methodologies and the integration of multi-scale remotely sensed, physiological, and paleoecological measurements to provide a comprehensive assessment of drought response, and predictions of forest response under future climate scenarios. We aim to provide a systematic and comprehensive quantification of the degree, scale and mechanism of tropical forest responses to recent and historical droughts in Amazonian forests. We will utilize previously developed models and remote sensing techniques and products for several sensors, and an established macro-scale hydrological model to compare distributed and watershed-aggregated hydrological variables with remote sensing data at scales up to those of a major drought. A novel aspect of our study will be the integration of multi-sensor remote sensing, contemporary physiological measurements, and the analysis of an extensive paleoecological dataset. We will examine the role that water use efficiency and stem flow of trees plays in responding to seasonal and annual water depletion through the analysis of leaf isotopes. We will compare field-based WUE measurements with hyperspectral and high resolution optical and lidar remotely sensed data to examine mortality based on estimates of drought severity, and compare this with moderate resolution satellite image data (non-photosynthetic vegetation [NPV]) and canopy thermal stress). We will analyze paleoecological data that reconstruct precipitation changes, megadroughts, forest response, and fire occurrence at sub-decadal resolution for the last 5000 years. These data will provide an indication of variability in past drought frequency and intensity and the vegetation and fire responses to those episodes. Our research and analysis techniques will aid future scientific efforts and policy planning for conservation organizations and government agencies.

Publications:

Anderson, L. O., Aragao, L. E. O. C., Gloor, M., Arai, E., Adami, M., Saatchi, S. S., Malhi, Y., Shimabukuro, Y. E., Barlow, J., Berenguer, E., Duarte, V. 2015. Disentangling the contribution of multiple land covers to fire-mediated carbon emissions in Amazonia during the 2010 drought. Global Biogeochemical Cycles. 29(10), 1739-1753. DOI: 10.1002/2014GB005008

Asbjornsen, H., Campbell, J. L., Jennings, K. A., Vadeboncoeur, M. A., McIntire, C., Templer, P. H., Phillips, R. P., Bauerle, T. L., Dietze, M. C., Frey, S. D., Groffman, P. M., Guerrieri, R., Hanson, P. J., Kelsey, E. P., Knapp, A. K., McDowell, N. G., Meir, P., Novick, K. A., Ollinger, S. V., Pockman, W. T., Schaberg, P. G., Wullschleger, S. D., Smith, M. D., Rustad, L. E. 2018. Guidelines and considerations for designing field experiments simulating precipitation extremes in forest ecosystems. Methods in Ecology and Evolution. 9(12), 2310-2325. DOI: 10.1111/2041-210x.13094

Brum, M., Vadeboncoeur, M. A., Ivanov, V., Asbjornsen, H., Saleska, S., Alves, L. F., Penha, D., Dias, J. D., Aragao, L. E. O. C., Barros, F., Bittencourt, P., Pereira, L., Oliveira, R. S. 2018. Hydrological niche segregation defines forest structure and drought tolerance strategies in a seasonal Amazon forest. Journal of Ecology. 107(1), 318-333. DOI: 10.1111/1365-2745.13022

Bush, M. B., Correa-Metrio, A., McMichael, C. H., Sully, S., Shadik, C. R., Valencia, B. G., Guilderson, T., Steinitz-Kannan, M., Overpeck, J. T. 2016. A 6900-year history of landscape modification by humans in lowland Amazonia. Quaternary Science Reviews. 141, 52-64. DOI: 10.1016/j.quascirev.2016.03.022

Bush, M. B., McMichael, C. H., Piperno, D. R., Silman, M. R., Barlow, J., Peres, C. A., Power, M., Palace, M. W. 2015. Anthropogenic influence on Amazonian forests in pre-history: An ecological perspective. Journal of Biogeography. 42(12), 2277-2288. DOI: 10.1111/jbi.12638

Bustamante, M. M. C., Roitman, I., Aide, T. M., Alencar, A., Anderson, L. O., Aragao, L., Asner, G. P., Barlow, J., Berenguer, E., Chambers, J., Costa, M. H., Fanin, T., Ferreira, L. G., Ferreira, J., Keller, M., Magnusson, W. E., Morales-Barquero, L., Morton, D., Ometto, J. P. H. B., Palace, M., Peres, C. A., Silverio, D., Trumbore, S., Vieira, I. C. G. 2015. Toward an integrated monitoring framework to assess the effects of tropical forest degradation and recovery on carbon stocks and biodiversity. Global Change Biology. 22(1), 92-109. DOI: 10.1111/gcb.13087

Chen, Y., Randerson, J. T., Morton, D. C. 2015. Tropical North Atlantic ocean-atmosphere interactions synchronize forest carbon losses from hurricanes and Amazon fires. Geophysical Research Letters. 42(15), 6462-6470. DOI: 10.1002/2015GL064505

Frolking, S., Hagen, S., Braswell, B., Milliman, T., Herrick, C., Peterson, S., Roberts, D., Keller, M., Palace, M. 2017. Evaluating multiple causes of persistent low microwave backscatter from Amazon forests after the 2005 drought. PLOS ONE. 12(9), e0183308. DOI: 10.1371/journal.pone.0183308

Morton, D. C., Nagol, J., Carabajal, C. C., Rosette, J., Rosette, J., Palace, M., Cook, B. D., Vermote, E. F., Harding, D. J., North, P. R. J. 2016. Morton et al. reply. Nature. 531(7594), E6-E6. DOI: 10.1038/nature16458

Palace, M. W., McMichael, C. N. H., Braswell, B. H., Hagen, S. C., Bush, M. B., Neves, E., Tamanaha, E., Herrick, C., Frolking, S. 2017. Ancient Amazonian populations left lasting impacts on forest structure. Ecosphere. 8(12), e02035. DOI: 10.1002/ecs2.2035

Palace, M., Herrick, C., DelGreco, J., Finnell, D., Garnello, A., McCalley, C., McArthur, K., Sullivan, F., Varner, R. 2018. Determining Subarctic Peatland Vegetation Using an Unmanned Aerial System (UAS). Remote Sensing. 10(9), 1498. DOI: 10.3390/rs10091498

Palace, M., Sullivan, F. B., Ducey, M., Herrick, C. 2016. Estimating Tropical Forest Structure Using a Terrestrial Lidar. PLOS ONE. 11(4), e0154115. DOI: 10.1371/journal.pone.0154115

Sullivan, F. B., Ducey, M. J., Orwig, D. A., Cook, B., Palace, M. W. 2017. Comparison of lidar- and allometry-derived canopy height models in an eastern deciduous forest. Forest Ecology and Management. 406, 83-94. DOI: 10.1016/j.foreco.2017.10.005

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

• Drought-induced vegetation change and fire in Amazonian forests: past, present, and future   --   (Michael Palace, Steve Frolking, Crystal McMichael, Bobby Braswell1, Dar Alexander Roberts, Mark Bush, Douglas Morton, Michael Keller, Heidi Asbjornsen, Luiz Aragao, Laerte Ferreria, Matt Vadenboncoeur, Mark Ducey, Stephen Hagen, Tom Milliman, Christina Herrick)   [abstract]

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

• NASA Terrestrial Ecology (TE) Project Profile