Julio Betancourt


I am a Lead Scientist in the National Research Program, Water Mission Area, USGS and an Adjunct Professor at the University of Arizona, Tucson, where I was co-located as a federal scientist for 30 years. In 2013, I moved to USGS Headquarters in Reston, VA, where I am gradually adjusting to being an Easterner. I am a broadly-trained geoscientist and ecologist focused on how climate affects terrestrial ecosystems on spatial and temporal scales critical for physical and biological processes. A main objective is to establish baselines for detecting and forecasting change, and for developing rational approaches to managing water and other natural resources under an uncertain and changing climate.

I am a Lead Scientist in the National Research Program (NRP), Water Mission Area, USGS, and an Adjunct Professor at the University of Arizona, where I was collocated as a federal scientist for more than 30 years. In January 2013, I moved to USGS Headquarters in Reston.

My research is focused on how climate variability affects terrestrial ecosystems on spatial and temporal scales critical for physical and biological processes. I am cross trained in geosciences, hydrology, climatology and ecology, and have a broad set of field and analytical skills typically employed in paleoecology, paleoclimatology, hydrology, hydroclimatology, geomorphology, and ecology. I also have hard-won experience and skills in translational science. My research and outreach focuses largely on the western U.S., where water resources are scarcest, much of the Nation's recent population growth is occurring, and relatively unspoiled landscapes are now undergoing dramatic change. I have also conducted field studies in Argentina, Bolivia, Chile, Mexico and Peru.

I integrate diverse methods, including paleo studies, long-term monitoring, and analyses of the instrumental record to study and understand the history, rates, dynamics and causes of climate, hydrological and ecosystem change at annual to millennial time scales. A good portion of my career has been devoted to exploiting the full potential of fossil rodent middens as a unique source of paleoenvironmental information in arid lands over the past 50,000 years. These deposits are rich amalgamations of plant fragments, pollen, fecal pellets, bones, and insects imbedded in crystallized rodent urine and preserved in rock crevices and caves for tens of millennia. My colleagues, students and I have helped develop and synthesize the midden record in North America, and we were responsible for discovering and developing it in South America. The resulting midden chronologies serve as critical baselines for interpreting ongoing landscape and climatic changes, including the causes, rates and pathways of migration for dominant plants.

I am a firm believer in translational science. In 2005, I co-founded a USA-National Phenology Network that is aimed at observing and predicting how plants and animals will respond to climate change in the U.S., engaging the public as citizen scientists, and informing adaptive strategies (www.usanpn.org). In 2008, I also co-founded a non-profit in the Southern Arizona entrusted with coordinating research, education and mitigation of African buffelgrass invasion and its impact on conservation and fire management (www.buffelgrass.org).

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Webb, R.H., Betancourt, J.L., Turner, R.M., and Johnson, R.R. 2013.  Requiem for the Santa Cruz: An environmental history of an Arizona River. University of Arizona Press (book; In Press)

Davies, T.J., Wolkovich, E.M., Kraft, N.J.B., SalaminN., Allen, JM, Ault, T.R., Betancourt, J.L., Bolmgren, K., Cleland, E.E., CookB.I., Crimmins, T.M., Mazer, S.J., McCabe,G.J., McGill, B.J., Parmesan, C., Pau, S., Regetz, J., Schwartz,  M.D., and Travers,S. 2013. Strong evidence for evolutionary inertia in plant phenological responses. Journal of Ecology (In Press).

Powell, S.L., Hansen, A.J., Rodhouse, T.J., Garrett, Betancourt, J.L., L.K., Dicus, G.H., Lonneker, M.K. 2013. Woodland dynamics at the northern range periphery: A challenge for protected area managers. PLOS ONE 8(5) E70454.

Weppner, K.N., Pierce, J.L., and Betancourt, J.L. 2013. Holocene fire occurrence and alluvial responses at the leading edge of pinyon-juniper migration in the northern Great Basin, USA. Quaternary Research http://dx.doi.org/10.1016/j.yqres.2013.06.004

Ault, T.R, Henbry, G.M., de Beurs, K.M., Schwartz, M.D., Betancourt, J.L., and Moore, D. 2013. Lessons from the false spring of 2012, earliest on record in North America. EOS, Transactions of the American Geophysical Union 94, 181-182, DOI: 10.1002/2013EO200001

Pederson, G., Betancourt, J.L., McCabe, G.J. 2013. Regional patterns and proximal causes of the recent snowpack decline in the Rocky Mountains, USA.Geophysical Research Letters DOI: 10.1002/grl.50424.

Pierson, E.A., Turner, R.M., and Betancourt, J.L. 2013. Regional demographic trends from long-term studies of saguaro (Carnegiea gigantea) across the northern Sonoran Desert. Journal of Arid Environments 88, 57-69.

Frid, L., Holcombe, T., Morisette, J.T., Olsson, A.D., Brigham, L., Bean, T., Betancourt, J.L., and Bryan, K. 2013. Using state and transition modeling to account for imperfect knowledge in invasive species management. Invasive Plant Science and Management 6(1):36-47; DOI: http://dx.doi.org/10.1614/IPSM-D-11-00065.1: URL: http://dx.doi.org/10.1614/IPSM-D-11-00065.1.

Schwartz, M.D., Ault, T.R., Betancourt, J.L. 2012. Spring onset variations and trends in the continental USA: Past and regional assessment using temperature-based indices. International Journal of Climatology DOI: 10.1002/joc.3625.

Belnap, J., Ludwig, J.A., Wilcox, B., Bestlemeyer, B., Betancourt, J.L., Dean, W.J.D., Milton, S.J. 2012. Introduced and invasive species in novel rangeland ecosystems: Friends or Foes? Journal of Rangeland Ecology & Management 65: 569-578, DOI: 10.2111/REM-D-11-00157.1.

Weiss, J.L., Betancourt, J.L., Overpeck, J.T. 2012. Climatic limits on foliar phenology during major droughts in the southwestern U.S.A. Journal of Geophysical Research-Biogeosciences v.117, G03031, doi:10.1029/2012JG001993.

Cook, B.I, Wolkovich, E.M., Davies, T.J., Ault, T.R., Allen, J., Betancourt, J.L., Bolmgren, Cleland, E.E., Crimmins, T.M., Kraft, N.J.B., Lancaster, L.T., Mazer, S.J., McGill, B.J., McCabe, G.J., Parmesan, C., Pau, S., Regetz, J., Salamin, N., Schwartz, M.D., Travers, S.E.2012. Sensitivity of spring phenology to warming across temporal and spatial climate gradients in two independent databases. Ecosystems DOI: 10.1007/s10021-012-9584-5.

Olsson, A., Betancourt, J.L., Marsh, S., Crimmins, M. 2012. Constancy of local spread rates for buffelgrass (Pennisetum ciliare L.) in the Arizona Upland of the Sonoran Desert. Journal of Arid Environments 87, 136-143.

Betancourt, J.L. 2012. Reflections on the relevance of history in a nonstationary world. In Wiens, J.A, Hayward, G.D., Safford, H.D., and Giffen, C. (Eds),Historical Environmental Variation in Conservation and Natural Resource Management, Wiley-Blackwell, p. 307-318, DOI: 10.1002/9781118329726.ch23

Reynolds, A.C., Quade, J., Betancourt, J.L. 2012. Strontium isotopes and nutrient sourcing in a semi-arid woodland. Geoderma 189-190, 574-584 (doi:10.1016/j.geoderma.2012.06.029).

Wolkovich, E.M., Cook, B.I., Allen, J.M., Crimmins, T.M., Travers, S., Pau, S. Davies, T.J., Ault, T., Betancourt, J.L., Bolmgren, K., Kraft, N.J.B., Lancaster, L., Mazer, S.J., McCabe, G.J.,McGill, B.J., Parmesan, C., Regetz, J., Salamin, N., Schwartz, M.D., & Cleland, E.E. 2012. Warming experiments under-predict plant phenological responses to climate change, Nature doi:10.1038/nature11014

Schwartz, M.L., Betancourt, J.L., Weltzin, J. 2012. From Caprio’s Lilacs to the U.S.A. National Phenology Network. Frontiers in Ecology and the Environment 10, 324–327, doi:10.1890/110281

Pigati, J.S., Latorre, C., Rech, J.A., Betancourt, J.L., Martinez, K.E., and Budahn, J.R. 2012. Accumulation of “impact markers” in desert wetlands and implications for the Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences www.pnas.org/cgi/doi/10.1073/pnas.1200296109

Neilson,J.W., Quade, J., Ortiz, M., Nelson,W.N., Legatzki, A., Tian, F., LaComb, M., Betancourt, J.L., Wing, R.A., Soderlund, S.A., Maier, R.M. 2012. Life at the Hyperarid Margin: Novel Bacterial Diversity in Arid Soils of the Atacama Desert, Chile. Extremophiles 16:553–566

Olsson, A., Betancourt, J.L., McClaran, M., Marsh, S. 2012. Sonoran Desert ecosystem transformation by a C4 grass without the grass-fire cycle. Diversity & Distributions 18, 10-21.

Diaz, F.P., Latorre, C.L., Maldonado, A., Quade, J., and Betancourt, J.L. 2011. Rodent middens reveal episodic, long-distant plant colonizations across the hyperarid Atacama Desert during the last 34,000 years. Journal of Biogeography DOI: 10.1111/j.1365-2699.2011.02617.x

McCabe, G.J., Ault, T.R., Cook, B.I., Betancourt, J.L., and Schwartz, M.D. 2011, Influences of the El Niño Southern Oscillation and the Pacific Decadal Oscillation on the timing of North American spring. International Journal of Climatology DOI: 10.1002/joc.3400

Ault, T., Macalady, A., Pederson, G., Betancourt, J.L. Schwartz, M.D., 2011. Northern Hemisphere modes of variability and the timing of spring in Western North America. Journal of Climate 24, 4003-4014.

Pederson, G.T., Gray, S.T., Woodhouse, C.A., Betancourt, J.L., Fagre, D.B., Littel, J.S., Watson, E., Luckman, B.H., Graumlich, L.J. 2011. The unusual nature of the snowpack decline in the North American cordillera. Science 333, 332-335.

Pau, S., Wolkovich, E.M., Cook, B.I., Davies, T.J., Kraft, N.J.B., Bolmgren, K, Betancourt, J.L., and Cleland, E.E. 2011, A framework for predicting phenology by integrating ecology, evolution and climate science. Global Change Biology 17, 3633–3643.

Holmgren, C.A., Betancourt, J.L., and Rylander, K.A. 2011. Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, MexicoQuaternary Research 75, 647-657.

Henebry, G.M. and Betancourt, J.L.. 2010. Toward a U.S. National Phenological Assessment. EOS, Transactions, American Geophysical Union 91(1), 3.

Butterfield, B.J., J.L. Betancourt, R.M. Turner, and J.M. Briggs, 2010, Facilitation drives 65 years of vegetation change in the Sonoran Desert. Ecology 91, 1132-1139.

Holmgren, C.A., Betancourt, J.L., and Rylander, K.A., 2010, A long-term vegetation history of Joshua Tree National Park: Journal of Quaternary Sciences, 25, 222-236.

Placzek, C., Quade, J., Betancourt, J.L., Patchett, P.J., Rech, J.A., Latorre, C., Matmon, A., Holmgren, C., and English, N.B., 2009, Climate in the dry, Central Andes over geologic, millennial, and interannual timescales: Annals of the Missouri Botanical Gardens 6, 386-397.

Jackson, S.T., Betancourt, J.L., Booth, R.K., Gray, S.T. 2009.  Ecology and the ratchet of events: climate variability, niche dimensions, and species distributions. Proceedings of the National Academy of Sciences, DOI 10.1073/PNAS.0901644106.

Hereford, R. and Betancourt, J.L. 2009. Historic geomorphology of the San Pedro River: archival and physical evidence. In: Stromberg, J. and Tellman, B., Ed.,Ecology and Conservation of Desert Riparian Ecosystems: The San Pedro River Example. University of Arizona Press, Tucson, p. 232-250.

Safford, H.D., Betancourt, J.L., Hayward, G.D., Wiens, J.A., and Regan, C.M. 2008. Land management in the Anthropogene: Is history still relevant? Eos Trans. AGU, 89(37), doi:10.1029/2008EO370004.

McCabe, G.J., Betancourt, J.L., Gray, S.T., Palecky, M. A., Hidalgo, H.G., 2008 Associations of multi-decadal sea-surface temperature variability with U.S. droughtQuaternary International 188, 31-40.

Quade, J., Rech, J., Betancourt, J., Latorre, C., Quade, B., Rylander, K.A., Fisher, T., 2008. Paleowetlands and regional climate change in the central Atacama Desert, northern Chile. Quaternary Research, 343-360.

Milly, P.C.D., Betancourt, J.L., Falkenmark, M., Hirsch, R.H., Kindzewicz, Z., Lettenmaier, D.P., Stouffer, R.J., 2008, Stationary is dead: Whither water management: Rethinking approaches to planning and design in a changing climate. Science 319, 573-574.

Holmgren, C.A., Rosello, E., Latorre, C., and Betancourt, J.L. 2008. Late-Holocene fossil rodent middens from the Arica region of northernmost Chile. Journal of Arid Environments 72, 677-686.

Quade, J., Rech, J., Latorre, C., Betancourt, J., Gleason, E., Kalin-Arroyo, M., 2007, Soils at the hyperarid margin: the isotopic composition of soil carbonate from the Atacama Desert. Geochimica et Cosmochima Acta 71, 3772-3795.

Gray, S.T., Graumlich, L. J., and Betancourt, J.L. 2007. Annual precipitation in the Yellowstone National Park region since AD 1173. Quaternary Research, 68, 18-27

Betancourt, J. L., M. D. Schwartz, D. D. Breshears, C. A. Brewer, G. Frazer, J. E. Gross, S. J. Mazer, B. C. Reed, and B. E. Wilson, 2007. Evolving plans for the USA National Phenology Network. Eos Trans. AGU, 88 (19), 211.

McCabe, G., Betancourt, J.L., Hidalgo, H.G. 2007. Associations of decadal to multidecadal sea-surface temperature variability with Upper Colorado River flow.Journal of the American Water Resources Association 43, 183-192.

Holmgren, C., Norris, J., Betancourt, J. L. 2007. Inferences about winter temperatures and summer rains from the late Quaternary record of C4 perennial grasses and C3 desert shrubs in the northern Chihuahuan Desert. Journal of Quaternary Science 22, 141-161.

Parks, J. A., Dean, J. S., and Betancourt, J. L. 2006. Tree rings, drought and the Pueblo Abandoment of south-central New Mexico in the 1670s. D. E. Doyel and J. S. Dean, Eds., Environmental Change and Human Adaptation in the Ancient Southwest, University of Utah Press, p. 214-227.

Drees, K.P., Neilson, J.W., Betancourt, J.L., Quade, J., Henderson, D.A., Pryor, B., and Maier, R.M. 2006. Bacterial community structure of soils in a hyperarid region of the Atacama Desert. Applied and Environmental Microbiology 72, 7902-7908.

Smith, F.A. and Betancourt, J.L. 2006. Predicting woodrat (Neotoma) responses to anthropogenic warming from studies of the paleomidden record. Journal of Biogeography 33, 2061-2076.

Parks, J. A., Dean, J. S., and Betancourt, J. L. 2006. Tree rings, drought and the Pueblo Abandoment of south-central New Mexico in the 1670s. D. E. Doyel and J. S. Dean, Eds., Environmental Change and Human Adaptation in the Ancient Southwest, University of Utah Press, p. 214-227.

Holmgren, C., Betancourt, J.L., and Rylander, K.A. 2006. A 36,000-yr history of the Peloncillo Mountains, southeastern Arizona, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 240, 405-422.

Gray, S.T., Betancourt, J.L., Jackson, S.T., Eddy, R. 2006. Role of multidecadal climate variability in a range extension of pinyon pine. Ecology 87, 1124-1130.

Latorre, C., Betancourt, J.L., and Arroyo, M.T.K. 2006. Vegetation and climate history of a perennial river canyon in the Rio Salado Basin (22 °S) of northern Chile. Quaternary Research 65, 450-466.

Keeley, J.E., Allen, C.D., Betancourt, J.L., Chong, G.W., Fotheringham, C.J. and Safford, H.D. 2006. A 21st Century Perspective on Postfire Seeding. Journal of Forestry March 2006, pp. 103-104.

Norris, J.T., Jackson, S.T., and Betancourt, J.L. 2006. Classification tree and minimum-volume ellipsoid analyses of the distribution of ponderosa pine in the western USA. Journal of Biogeography 33, 342-360.

Betancourt, J.L., Schwartz, M.D., Breshears, D.D., Cayan, D.R., Dettinger, M.D., Inouye, D.W., Post, E., and Reed, B.C. 2005. Implementing a U.S.A.-national phenology network. Eos Transactions American Geophysical Union 86, 539.

Maldonado, A., Betancourt, J. L., Latorre, C. and Villagran, C. 2005. Pollen analyses from a 50,000-yr rodent midden series in the southern Atacama Desert (25°30'S). Journal of Quaternary Science 20, 493-507.

Latorre, C., Betancourt, J. L., Rech, J. A., Quade, J., Holmgren, C., Placzek, C., Maldonado, A., Vuille, M., and Rylander, K. A. 2005. Late Quaternary History of the Atacama Desert. In 23 Degrees South: The Archaeology and Environmental History of the Southern Deserts (M. Smith and P. Hesse, Eds.), National Museum of Australia Press, Canberra, Australia, pp. 73-90.

Reynolds, A. C., Betancourt, J. L., Quade, J., Patchett, P. J., Dean, J. S., and Stein, J. 2005.  87Sr/86Sr sourcing of ponderosa pine used in Anasazi Great House construction at Chaco Canyon, New Mexico. Journal of Archaeological Science 32, 1061-1075.

Jackson, S. T., Betancourt, J. L., Lyford, M. E., Gray, S. E., and Rylander, K. A. 2005. A 40,000-year woodrat-midden record of vegetational and biogeographic dynamics in northeastern Utah. Journal of Biogeography 32, 1085-1106.

Betancourt, J. L. 2004. Arid lands paleobiogeography: The fossil rodent midden record in the Americas. In Lomolino, M. V. and Heaney, L. R., Eds., Frontiers in Biogeography: New Directions in the Geography of Nature. Sinauer Associates Inc, p. 27-46.

Maier, R. M., Drees, K. P., Neilson, J. W., Henderson, D. A., Quade, J. and Betancourt, J.L. 2004. Microbial life in the Atacama Desert. Science 306, 1280.

Gray, S. T., Fastie, C., Jackson, S. T., and Betancourt, J. L. 2004. Tree-ring based reconstruction of precipitation in the Bighorn Basin, Wyoming since A.D. 1260.Journal of Climate 17, 3855-3856.

Gray, S. T., Jackson, S. T., and Betancourt, J. L. 2004. Tree-ring based reconstructions of interannual to decadal-scale precipitation variability for northeastern Utah since 1226 A.D. Journal of the American Water Resources Association 40, 947-960.

Barclay, A.D., Betancourt, J.L., and Allen, C.D., 2004. Effects of seeding with ryegrass (Lolium multiflorum) on vegetation recovery following fire in a ponderosa pine (Pinus ponderosa) forest. International Journal of Wildland Fire 3, 183-194.

Gray, S.T., Graumlich, L.J., Betancourt, J.L. and Pederson, G.T. 2004. A tree-ring based reconstruction of the Atlantic Multidecadal Oscillation since 1567 A.D.Geophysical Research Letters 31, L12205, doi:10.1029/2004GL019932.

McCabe, G. J., Palecki, M. A., and Betancourt, J. L. 2004. Pacific and Atlantic Ocean influences on multidecadal drought frequency in the United States.Proceedings of the National Academy of Sciences 101, 4136-4141.

Milne, B. T., Moore, D. I., Betancourt, J. L., Parks, J. A., Swetnam, T. W., Parmenter, R. R., and Pockman, W. T. 2003. Multidecadal drought cycles in south-central New Mexico: Patterns and Consequences. In Climate Variability and Ecosystem Response at Long-Term Ecological Research (LTER) Sites, D. Greenland, D. G. Goodin and R. C. Smith, Eds. Oxford University Press, p. 286-307.

Holmgren, C., Peñalba, M. C., Rylander, K. A., and Betancourt, J. L. 2003. A 16,000 14C yr BP packrat midden series from the U.S.A.-Mexico Borderlands.Quaternary Research 60, 319-329.

Lyford, M.E., Jackson, S.T., Betancourt, J.L. and Gray, S. 2003,Influence of landscape structure and climate variability in a late Holocene natural invasion.Ecological Monographs 73, 567-583.

Betancourt, J. L., 2003, Book Review of Force, E. R., Vivian, R. G., Windes, T. C. and Dean, J. S., 2000, “Relation of “Bonito” paleo-channels and base-level variations to Anasazi occupation, Chaco Canyon, New Mexico.” Tucson: Arizona State Museum Archaeological Series 194, vii + 49pp. ISBN 1-889747-72-6.Progress in Physical Geography 27, 308-309.

Betancourt, J.L., Grissino-Mayer, Salzer, M.W., and Swetnam, T.W. 2003. Reply to Genty and Baker. Quaternary Research 59, 364-378.

Hofreiter, M., Betancourt, J.L., Sbriller, A. P., Markgraf, V. and McDonald, H. G. 2003. Phylogeny, diet and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina. Quaternary Research 59, 364-378.

Smith, F. A. and Betancourt, J.L. 2003. The effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats) in Idaho and northwestern Utah. Quaternary Research 59, 160-171.

Gray, S. T., Betancourt, J. L., Fastie, C. L., Jackson, S. T. 2003. Patterns and sources of multidecadal oscillations in drought-sensitive tree-ring records from the central and southern Rocky Mountains. Geophysical Research Letters 30, 49-1-4, doi:10.1029/2002GL016154.

Latorre, C., Betancourt, J. L., Rylander, K. A., Quade, J. and Matthei, O., 2003, A 13.5-kyr vegetation history from the arid prepuna of northern Chile (22-23°S),Palaeogeography, Palaeoclimatology, Palaeoecology, 194, 223-246.

Rech, J. A., Pigati, J. S., Quade, J., and Betancourt, J. L., 2003, Re-evaluation of mid-Holocene wetland deposits at Quebrada Puripica, northern Chile,Palaeogeography, Palaeoclimatology, Palaeoecology, 194, 207-222.

Jackson, S. T., Lyford, M. E., Betancourt, J.L. 2002. A 4000-year record of woodland vegetation from Wind River Canyon, central Wyoming. Western North American Naturalist 62, 405-413.

Terwilliger, V.J., Betancourt, J.L., Leavitt, S.W., and Van de Water, P.K. 2002, Leaf cellulose δD and δ18O trends with elevation and climate in semi-arid species. Geochimica et Coscomochima Acta 66, 3887-3900.

Betancourt, J.L. and Saavedra, B., 2002, Nuevo método paleoecológico para el estudio de zonas áridas en Sudamérica: paleomadrigueras de roedores (New paleoecological method for Quaternary studies in arid lands of South America: Rodent middens). Revista Chilena de Historia Natural, 75, 527-546.

Betancourt, J.L., Grissino-Mayer, Salzer, M.W., and Swetnam, T.W., 2002, A test of ‘annual resolution’ in stalagmites using tree rings. Quaternary Research 58, 197-199.

Lyford, M. E., Betancourt, J. L. and Jackson, S. T. 2002. Holocene vegetation and climate history of the northern Bighorn Basin, southern Montana, U.S.A.Quaternary Research 58, 171-181.

Pearson, S. and Betancourt, J.L. 2002. Understanding arid environments using fossil rodent middens. Journal of Arid Environments 50, 499-511.

Rech, J. A., Quade, J. and Betancourt, J. L., 2002, Late Quaternary paleohydrology of the central Atacama Desert (22-24°S), Chile. Geological Society of America Bulletin 114, 334-348.

Latorre, C.L., Betancourt, J. L., Rylander, K. A., and Quade, J. A., 2002, Vegetation invasions into Absolute Desert: a 45,000-year rodent midden record from the Calama-Salar de Atacama Basins, Chile. Geological Society of America Bulletin 114, 349-366.

Betancourt, J.L., 2002, Book Review: Interhemispheric Climatic Linkages, Edited by Vera Markgraf. Arctic, Antarctic & Alpine Research 34, 226-227.

Van de Water, P.D., Leavitt, S.W., and Betancourt, J.L., 2002, Leaf cellulose δ13C variability with elevation, slope aspect and precipitation in the U.S. Southwest. Oecologia 132, 332-343.

Kuch, M. Rohland, N., Betancourt, J.L., Latorre, C., Steppan, S., and Poinar, H. N. 2002, Molecular analysis of an 11,700-year old rodent midden from the Atacama Desert, Chile. Molecular Ecology, 11, 913-924.

Pedicino, L., Leavitt, S. W., Betancourt, J. L. 2002, Historical variations in δ13Cleaf of herbarium specimens in the southwestern U.S. Western North American Naturalist 62, 348-359.

Hunter, K. L., Betancourt, J. L., Riddle, B. R., Van Devender, T. R., Cole, K. L., and Spaulding, W. G. 2001. Ploidy race distributions since the Last Glacial Maximum in the North American desert shrub, Larrea tridentataGlobal Ecology and Biogeography 10, 521-533.

English, N.E., Betancourt, J.L., Dean, J.S., Quade, J. 2001. Strontium isotopes reveal source of architectural timber at Chaco Canyon, New Mexico. Proceedings of the National Academy of Sciences 98, 11891-11896.

Placzek, C., Quade, J. and Betancourt, J. L., 2001, Holocene lake level fluctuations of Lago Aricota, southern Peru. Quaternary Research 56, 181-190.

Holmgren, C., Betancourt, J.L., Rylander, K.A., Roque, J., Tovar, O., Zeballos, H., Linares, E., and Quade, J., 2001, Holocene vegetation history from fossil rodent middens near Arequipa, Peru. Quaternary Research. 56, 242-251.

Quade, J., Rech, J., Betancourt, J.L. and Latorre, C. 2001. Mid-Holocene climate in the south-central Andes: Humid or Dry? Science 292, 2391a.

Brown, T. J. and Betancourt, J. L. 2000. Effect of climate variability and forecasting on fuel treatment schedules in the western U.S. Proceedings of the USDA and DOI Fire Sciences Workshop.

Betancourt, J.L. 2000. Book Review: A Natural History of the Sonoran Desert, edited by Steven J. Phillips and Patricia Wentworth Cornus, Univ. of California Press, 1999. Geotimes v., p. 34.

Anderson, R.S., J.L. Betancourt, J.I. Mead, R.H.Hevly and D.P. Adam. 2000. Middle- and late-Wisconsin paleobotanic and paleoclimatic records from the southern Colorado Plateau, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 155, 31-57.

Betancourt, J. L., Rylander, K. A., Peñalba, C., and McVickar, J. L. 2000. Late Quaternary vegetation history of Rough Canyon, south-central New Mexico, USA.Palaeogeography, Palaeoclimatology, and Palaeoecology, 165, 71-95

Betancourt, J.L., Latorre, C., Rech, J. A., Quade, J., and Rylander, K. A., 2000, A 22,000-yr record of monsoonal precipitation from northern Chile’s Atacama Desert. Science 289, 1542-1546.

Pendall, E., Betancourt, J. L. and Leavitt. 1999. Paleoclimatic significance of δD and δ13C in pinyon pine needles from packrat middens spanning the last 40,000 years. Palaeogeography, Palaeoclimatology and Palaeoecology 147, 53-72.

Swetnam, T.W., C.D. Allen, and J.L. Betancourt, 1999. Applied historical ecology: Using the past to manage for the future. Ecological Applications 64, 1189-1206.

White, P. S., J. Harrod, W. Romme, and J. Betancourt 1999. The role of disturbance and temporal dynamics. In: Ecological Stewardship: A common reference for ecosystem management (Johnson, N.C., A. J. Malk, W. T. Sexton, and R.Szaro, eds.). Oxford, England: Elsevier Science Ltd., p. 281-312.

Connin, S. L., Betancourt, J. L. and Quade, J. 1998. Late Pleistocene C4 plant dominance and summer rainfall in the southwestern U.S.A. from isotopic study of herbivore teeth. Quaternary Research 2, 170-193.

Smith, F. A. and Betancourt, J.L. 1998. Response of bushy-tailed woodrats (Neotoma cinerea) to late Quaternary climate change in the Colorado Plateau.Quaternary Research 50, 1-11.

Swetnam, T.W. and Betancourt, J.L. 1998. Mesoscale disturbance and ecological response to decadal-scale climate variability in the American Southwest. Journal of Climate 11, 3128-3147.

Allen, C.D., J.L. Betancourt, and T.W. Swetnam. 1998. Landscape Changes in the Southwestern United States: Techniques, Long-Term Datasets, and Trends. In T. Sisk, Ed., Land Use History of North America: Providing a Context for Understanding our Changing Environment. USGS Biological Science Report, USGS/BRD/BSR-1998-0003: 71-84.

Betancourt, J. L. 1998. Book Review: The Call of Distant Mammoths- Why the Ice Age Mammals Disappeared, by Peter Ward, Springer-Verlag, 1997.Palaeogeography, Palaeoclimatology and Palaeoecology 141, 163-175.

Betancourt, J. L. 1998. Book Review: Biomass Burning and Global Change, Volumes I and II, edited by Joel S. Levine, The MIT Press, 1997. Bulletin of the American Meteorological Society v. 79l, p.

Markgraf, V., Betancourt, J.L., and Aasen Rylander, K. 1997. Late Holocene rodent middens from Rio Limay, Neuquen Province, Argentina: The Holocene 7, 325-329.

Shanley, J.B, Kendall, C., Pendall, E., Stevens, L.R., Michel, R.L., Phillips, P.J., Forester, R.M., Naftz, D.L., Liu, B., Stern, L., Wolfe, B.B., Chamberlain, C. P., Leavitt, S.W., Heaton, T.H.E., Mayer, B., Cecil, L.D., Lyons, W.B., Katz, B.G., Betancourt, J., McKnight, D.M., Blum, J.D., Edwards, T.W.D., House, H.R., Ito, E., Aravena, R., and Whelan, J.F., 1997. Isotopes as Indicators of Environmental Change. In: Kendall, C. and McDonnell, J.J., editors, Isotopes in Catchment Hydrology, chapter 23, Elsevier.

Dickfoss, P., Betancourt, J.L.. and Thompson, L. 1997. History and paleoclimatic potential of Candelaria Ice Cave, west-central New Mexico. In: Zidek, G., Ed., A Natural History of El Malpais: New Mexico Bureau of Mines & Mineral Resources, Bulletin 156t, p. 91-112. .

Betancourt, J.L. 1996. Long and short-term climatic influences on southwestern shrublands. In: Barrow, J. R.; MacArthur, E. D. ; Sosebee, R. E.; Tausch, R.J., comps. 1996. Proceedings: symposium on shrubland ecosystem dynamics in a changing climate; 1995 May 23-25; Las Cruces, NM. Gen. Tech. Rep. INT-GTR-338. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, p. 5-9.

Gottfried, G.J., Swetnam, T.W., Allen, C.D., Betancourt, J.L., Chung-MacCoubrey, A. 1996. Pinyon-juniper woodlands. In: Finch, D. M. and Tainter, J. A., Ecology, Diversity and Sustainability of the Middle Rio Grande Basin. USDA Forest Service General Technical Report RM-GTR-278, p. 95-132.

Burgess, T.L., Betancourt, J.L., and Busby, J. 1995. Sampling bias in geographic patterns of plant species richness in the Sonoran Desert, U.S.A and Mexico, and Northern Territory, Australia. Proceedings of the Sky Island Conference, September 1994, Tucson, AZ, USDA, Forest Service General Technical Report RM-GTR-264, p. 84-90.

Betancourt, J.L., Craig, R., Burgess, T.L., Pierson, E.A., Shiozawa, L. 1995. A climate-plant distribution model for the Sonoran Desert- Annual Progress Report 1994. National Biological Service, Global Change Research Program, Sonoran Desert, p. 1-25.

Smith, F.A., Betancourt, J.L. and Brown, J.H., 1995. Effects of global warming on woodrat (Neotoma cinerea) body size during the last deglaciation. Science 270, 2012-2014.

Van de Water, P.D., Leavitt, S.L., and Betancourt, J.L. 1994, Trends in stomatal density and 13C/12C ratios of Pinus flexilis needles during last glacial/interglacial cycle. Science 264, 239-243.

Betancourt, J.L., Pierson, E.A., Aasen Rylander, K., Fairchild-Parks, J.A., and Dean, J.S. 1993. Influence of history and climate on New Mexico piñon-juniper woodlands. In: Aldon, E.F. and Shaw, D.W., (Eds.), Managing Piñon-Juniper Ecosystems for Sustainability and Social Needs: Proceedings of the Symposium April 26-30, Santa Fe, New Mexico. Gen. Tech. Rep. RM-236, Fort Collins, CO: USDA Forest Service, Rocky Mountain & Range Experiment Station, p. 42-62.

Webb, R.H. and Betancourt, J.L., 1992, Climatic variability and flood frequency of the Santa Cruz River, Pima County, Arizona: U.S. Geological Survey Water-Supply Paper 2379.

Betancourt, J. L. and Tharp, V. L., eds., 1992. Proceedings of the Eight Annual Pacific Climate (PACLIM) Workshop, Asilomar, California, April, 1990: California Department of Water Resources, Interagency Ecological Studies Program, Technical Report 26, 257 p.

Swetnam, T.W. and Betancourt, J.L., 1992, Temporal patterns of ENSO-wildfire teleconnections in the southwestern United States. In Diaz, H. F. and Markgraf, V.,El Niño: Historical and paleoclimatic aspects of the Southern Oscillation. Cambridge University Press, 259-270.

Lowenstein, J. M., Rainey, W.N., and Betancourt, J. L., 1991, Immunospecific albumin in fossil packrat, porcupine and hyrax urine: Naturwissenschaften, 78, 26-27.

Betancourt, J.L., Schuster, W.S., Mitton, J.B., and Anderson, R.S., 1991, Fossil and genetic history of a pinyon pine (Pinus edulis) isolate: Ecology 72, 1685-1697.

Betancourt, J.L., Van Devender, T.R., and Martin, P.S., 1990, Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, 472 p.

Betancourt, J.L., Van Devender, T.R., and Martin, P.S., 1990, Introduction, in Betancourt, J.L., Van Devender, T.R., and Martin, P.S., (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 2-11.

Spaulding, W.G., Betancourt, J.L., Cole, K.L., and Croft, L., 1990, Packrat middens, their composition and methods of analysis, in Betancourt, J.L., Van Devender, T.R., and Martin, P.S., (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 59-84.

Webb, R.H., and Betancourt, J.L., 1990, The spatial distribution of radiocarbon ages from packrat middens, in Betancourt, J.L., Van Devender, T.R., and Martin, P.S., (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 85-102.

Betancourt, J.L., 1990, Late Quaternary biogeography of the Colorado Plateau, in Betancourt, J.L.., Van Devender, T.R., and Martin, P.S., (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 259-292.

Long, A., Warnecke, L., Betancourt, J.L., and Thompson, R.S., 1990, Deuterium variations in plant cellulose from packrat middens, in Betancourt, J.L., Van Devender, T.R., and Martin, P.S., (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 381-396.

Betancourt, J.L., Van Devender, T.R., and Martin, P.S., 1990, Synthesis and prospectus, in Betancourt, J.L., Van Devender, T.R., and Martin, P.S. (eds), Packrat middens: The last 40,000 years of biotic change: Tucson, Arizona, University of Arizona Press, p. 435-447.

Betancourt, J.L. and MacKay, A.M., eds., 1990, Proceedings of the Sixth Annual Pacific Climate (PACLIM) Workshop, Asilomar, California, March 5-8, 1989: California Department of Water Resources, Interagency Ecological Studies Program, Technical Report 23.

Betancourt, J.L., 1990, Introduction. in Betancourt, J. L. and MacKay, A.M., (eds), Proceedings of the Sixth Annual Pacific Climate (PACLIM) Workshop, Asilomar, California, March 5-8, 1989, California Department of Water Resources, Interagency Ecological Studies Program, Technical Report 23, p. 1-4.

Webb, R.H., and Betancourt, J.L., 1990, Climatic effects on flood frequency: An example from southern Arizona, in Betancourt, J.L. and MacKay, A.M., (eds), Proceedings of the Sixth Annual Pacific Climate (PACLIM) Workshop, Asilomar, California, March 5-8, 1989: California Department of Water Resources, Interagency Ecological Studies Program, Technical Report 23, p. 61-66.

Swetnam, T.R., and Betancourt, J.L., 1990, El Niño-Southern Oscillation (ENSO) phenomena and forest fires in the southwestern United States, in Betancourt, J.L. and MacKay, A. M.,(eds), Proceedings of the Sixth Annual Pacific Climate (PACLIM) Workshop, Asilomar, California, March 5-8, 1989, California Department of Water Resources, Interagency Ecological Study Program, Technical Report 23, p. 129-135.

Swetnam, T.R. and Betancourt, J.L., 1990, Fire-Southern Oscillation relations in the southwestern United States: Science 24, 1017-1020.

Betancourt, J. L. and Turner, R.M., 1988, Historic arroyo-cutting and subsequent channel changes at the Congress Street crossing, Santa Cruz River, Tucson, Arizona, in Whitehead, E.E., Hutchinson, C.F., Timmermann, B.N., and Varady, R.G. (eds), Arid Lands Today and Tomorrow: Boulder, Colorado, Westview Press, p. 1353-1371.

Betancourt, J.L., 1987, Paleoecology of pinyon-juniper woodlands, summary: Reno, Nevada, Proceedings, Pinyon-juniper Conference, U.S.D.A. Forest Service, General Technical Report INT, 215, 129-139.

Van Devender, T.R., Thompson, R.S., and Betancourt, J.L., 1987, Vegetation and history of the Southwest, the nature and timing of the late Wisconsin-Holocene transition, in Ruddiman, W.F. and Wright, H.E., Jr. (eds), North America and adjacent oceans during the last deglaciation: Boulder, Colorado, Geological Society of America, The Geology of North America, v. K3, p. 323-352

Betancourt, J.L., Dean, J.A., Hull, Herbert, 1986, Prehistoric long-distance transport of construction beams, Chaco Canyon, New Mexico: American Antiquity, 51, 370-375.

Betancourt, J.L., Van Devender, T.R., and Rose, Martin, 1986, Comparison of plant macrofossils in woodrat (Neotoma) and porcupine (Erethizon dorsatum) middens in the western United States: Journal of Mammalogy, 67, 266-273.

Betancourt, J.L., and Biggar, Norma, 1985, Preliminary assessment of late Quaternary vegetation and climate of southeastern Utah based on analyses of packrat middens: Columbus, Ohio, Batelle Memorial Institute, Office Nuclear Waste Isolation, Technical Report v. 570, 120 p.

Betancourt, J.L., and Davis, O.K., 1984, Fossil packrat middens from Canyon de Chelly, northeastern Arizona, paleoecological and archeological implications: Quaternary Research, 21, 556-564.

Betancourt, J.L., Long, A., Donahue, D., Jull, A.J.T., and Zabel, T., 1984, Precolumbian age for North American Corispermum L. (Chenopodiaceae) confirmed by accelerator radiocarbon dating: Nature, 311, 653-655.

Betancourt, J.L., 1984, Late Quaternary plant zonation and climate in southeastern Utah: Great Basin Naturalist, 4, 1-35.

Van Devender, T.R., Betancourt, J.L., and Wimberly, M., 1984, Biogeographic implications of a packrat midden sequence from the Sacramento Mountains, south-central New Mexico: Quaternary Research, 22, 344-360.

Betancourt, J.L., Van Devender, T.R., and Martin, P.S., 1983, Fossil packrat middens from Chaco Canyon, New Mexico: Cultural and ecological significance: in Wells, S.G., Love, D.W., and Gardner, T.W. (eds), Chaco Canyon country, a field guide to the geomorphology, Quaternary geology, paleoecology, and environmental geology of northwestern New Mexico: Albuquerque, American Geomorphological Field Group, p. 207-217.

Samuels, M. and Betancourt, J.L., 1982, Modeling the long-term effects of fuelwood harvests on pinyon-juniper woodlands: Environmental Management 6, 505-515.

Betancourt, J.L., 1981, Reconnaissance of archeological resources in the southern Quitman Mountains, Hudspeth County, Texas: Austin, Texas Antiquities Committee Permit Series 6, 83-114.

Betancourt, J.L., 1981, Reconnaissance of archeological resources in the southern Quitman Mountains, Hudspeth County, Texas: Austin, Texas Antiquities Committee Permit Series, 6, 27-82.

Betancourt, J.L., 1981, A history of Mescalero Apache-U.S. Army encounters in Dog Canyon, New Mexico, 1849-1880: Albuquerque, USDA-Forest Service, Cultural Resources on the Lincoln National Forest Miscellaneous Papers, v. 34, p. 50-66.

Betancourt, J.L., and Van Devender, T.R., 1981, Holocene vegetation in Chaco Canyon, New Mexico: Science, 214, 658-660.

Betancourt, J.L., 1980, Historical overview of the lower Rio Puerco and Rio Salado, central New Mexico: in Wimberly, M. and Eidenbach, P. (eds), Reconnaissance study of the archeological and related resources of the lower Puerco and Salado drainages: Albuquerque, U.S. Army Corps of Engineers, p. 23-58.

Wimberly, M., Eidenbach, P., and Betancourt, J.L., 1979, Canyon del Perro, a history of Dog Canyon, New Mexico: Santa Fe, New Mexico Parks and Recreation Commission, 261 p.

Betancourt, J.L., 1978, An archeological synthesis of the Tucson Basin, Focus on the Santa Cruz Riverpark: Tucson, Arizona State Museum Archeological Series, v. 125, 108p.

Betancourt, J.L., 1978, Cultural resources within the proposed Santa Cruz Archeological District: Tucson, Arizona State Museum Archeological Series, v. 125, 113 p.

Betancourt, J.L., 1977, Archeological survey of a proposed lignite mine area, the Shell-Rockdale Lease: Austin, Texas Historical Commission, Archeological Survey, v. 21, 117 p.