National Research Program

Biotic Response to Climatic Variability and Human Impacts in Arid Lands

Biotic responses to climatic change or human manipulation are inherently complex because of wide differences in organism sensitivities and response times, the influence of history and scale, and the various interactions between organisms and with the physical system. In arid and semi-arid lands, which cover about 12.5 percent of the Earth's land surface, the effects of climatic variability on vegetation are greatly magnified, particularly because most plants exist near their physiological limits. How arid land vegetation might in turn affect climate is uncertain, though there is some indication that decreasing cover and increasing albedo could promote regional drought. Whether in response to projected Greenhouse climates or intensified land use, vegetation in such critical watersheds as the Rio Grande and Colorado River basins is apt to change in the near future. There is a need to understand the direction and rate of this change and how it might affect water use and availability in the region. The objectives of this project are to achieve a dynamic understanding of vegetation change and its relation to water resources; to develop such an understanding in a manner appropriate to the hierarchy of spatial and temporal scales implicit in a study of global change; and to determine whether the responses of dryland vegetation to global change are predictable from past and present behavior of vegetation. For additional information, see the home page for the Desert Laboratory, which is operated jointly by the University of Arizona's Department of Geosciences, Department of Ecology and Evolutionary Biology, and the U.S. Geological Survey.


Betancourt, J. L., in press, Reflections on the relevance of history in a nonstationary world. Chapter 23., 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.

McCabe, G.J., Ault, T.R., Cook, B.I., Betancourt, J.L., and Schwartz, M.D. , in press (web publication 11/15/11), Influences of the El Niño Southern Oscillation and the Pacific Decadal Oscillation on the timing of North American spring: International Journal of Climatology. (on-line abstract of preprint)

Diaz, F.P., Latorre, C.L., Maldonado, A., Quade, J., and Betancourt, J.L., 2012 (web publication 10/20/11), Rodent middens reveal episodic, long-distant plant colonizations across the hyperarid Atacama Desert during the last 34,000 years: Journal of Biogeography, v.39, no. 3, p. 510-525. (on-line abstract of journal article)

Olsson, A., Betancourt, J.L., McClaran, M., and Marsh, S., 2012, Sonoran Desert ecosystem transformation by a C4 grass without the grass-fire cycle: Diversity & Distributions, v .18, no. 1, p.10-21. (on-line abstract or on-line article in pdf format, 836 KB)

Ault, T., Macalady, A., Betancourt, J.L., Pederson, G., and Schwartz, M.D., 2011, Northern Hemisphere modes of variability and the timing of spring in Western North America: Journal of Climate, v. 24, p. 4003-4014. (on-line abstract of journal article)

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, Mexico: Quaternary Research, v. 75, p. 647-657. doi:10.1016/j.yqres.2011.01.008 (on-line abstract of journal article)

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, Predicting phenology by integrating ecology, evolution and climate science: Global Change Biology, v. 17, no. 12, p. 3633-3643. doi: 10.1111/j.1365-2486.2011.02515.x (on-line abstract of journal article)

Pederson, G.T., Gray, S.T., Woodhouse, C.A., Betancourt, J.L., Fagre, D.B., , Littell, J.S., Watson, E., Luckman, B.H., and Graumlich, L.J., 2011, The Unusual Nature of Recent Snowpack Declines in the North American Cordillera: Science, v. 333, no. 6040, p. 332-335. (on-line abstract of journal article)

Butterfield, B.J., Betancourt, J.L., Turner, R.M., and Briggs, J.M., 2010, Facilitation drives 65 years of vegetation change in the Sonoran Desert: Ecology, v. 91, no. 4, p. 1132-1139. doi: 10.1890/09-0145.1 (on-line abstract of journal article)

Henebry, G.M. and Betancourt, J.L, 2010, Toward a U.S. National Phenological Assessment: EOS, Transactions, American Geophysical Union, v. 91, no. 1, p. 3. (on-line abstract of article)

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, v. 25, no. 2, p. 222-236. (on-line abstract of journal article)

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

Jackson, S.T., Betancourt, J.L., Booth, R.K., and Gray, S.T., 2009, Ecology and the ratchet of events: climate variability, niche dimensions, and species distributions: Proceedings of the National Academy of Sciences, v 106, no. 17, suppl. 2, p. 19685-19692. (on-line abstract of journal article)

Holmgren, C.A. , Rosello, E. , Latorre, C. , Betancourt, J.L., 2008, Late-Holocene fossil rodent middens from the Arica region of northernmost Chile: Journal of Arid Environments, v. 72, no. 5, p. 677-686. (on-line abstract of journal article)

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. drought: Quaternary International, v. 188, p. 31-40. doi:10.1016/j.quaint.2007.07.001. (on-line abstract of journal article)

Milly, P.C.D., Betancourt, J., Falkenmark, M., Hirsch, R.M., Kundzewicz, Z.W., Lettenmaier, D.P., and Stouffer, R.J., 2008, Stationarity is dead: Whither water management?: Science, v. 319, no. 5863, p. 573-574. (on-line report in pdf format)

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, v. 96, no. 3, p. 386-397. (on-line abstract of journal article)

Quade, J. Rech, J.A., Betancourt, J.L., Latorre, C., Quade, B., Rylander, K.A., and Fisher, T., 2008, Paleowetlands and regional climate change in the central Atacama Desert, northern Chile: Quaternary Research, v. 69, p. 343-360. (on-line abstract of journal article)

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 Transactions, American Geophysical Union, v. 89, no. 37, doi:10.1029/2008EO370004. (on-line abstract)

Betancourt, J.L., Schwartz, M.D., Breshears, D.D., Brewer, C.A., Frazer, G., Gross, J.E., Mazer, S.J., Reed, B.C., and Wilson, B.E., 2007, Evolving plans for a USA National Phenology Network: Eos, Transactions American Geophysical Union, v. 88, p. 211.

Bowers, J. E., 2007, Has climatic warming altered spring flowering date of Sonoran Desert shrubs?: Southwestern Naturalist, v. 52, no. 3, p. 347-355. (on-line abstract of journal article)

Gray, S.T., Graumlich, L. J., and Betancourt, J.L. 2007, Annual precipitation in the Yellowstone National Park region since AD 1173: Quaternary Research, v. 68, p. 18-27. (on-line abstract of journal article)

Holmgren, C., Norris, J., and 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, v. 22, no. 2, p. 141-161. (on-line abstract or on-line journal article in pdf format, 2031 KB - published on-line in 2006 by John Wiley & Sons as a U.S. government work in the public domain)

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, v. 43, no. 1, p. 183–192. doi:10.1111/j.1752-1688.2007.00015.x (on-line abstract of journal article)

McCabe, G.J., Palecki, M.A., and Betancourt, J.L., 2007, Ocean influenences on multi-decadal drought frequency in the conterminous United States: Proceedings of the Pacific Climate, (PACLIM) workshop, p. 69-73.

McLaughlin, S.P. and Bowers, J.E., 2007, Effects of Exotic Grasses on Soil Seed Banks in Southeastern Arizona Grasslands: Western North American Naturalist, v. 67, no. 2, p. 206-208. (on-line abstract of journal article)

Quade, J., Rech, J.A., Latorre, C.H., Betancourt, J.L., Gleeson, E., Arroyo, M.T.K., 2007, Soils at the hyperarid margin: The isotopic composition of soil carbonate from the Atacama Desert: Geochimica et Cosmochimica Acta, v. 71, no. 15, p. 3,772-3,795. (on-line abstract of journal article)

Bowers, J. E., 2006, Branch length mediates flower production and inflorescence architecture of Fouquieria splendens (ocotillo): Plant Ecology, v. 186, no.1, p. 87-95. (on-line abstract of journal article)

Bowers, J.E., Bean, T.M., and Turner, R.M., 2006, Two decades of change in distribution of exotic plants at the Desert Laboratory, Tucson, Arizona: Madroño v. 53, p. 252-263. (on-line abstract of journal article)

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, v. 72, p. 7,902-7,908. (on-line abstract of journal article)

Gray, S.T., Betancourt, J.L., Jackson, S.T., and Eddy, R., 2006, Role of multidecadal climate variability in a range extension of pinyon pine: Ecology, v. 87, p. 1,124-1,130. (on-line abstract of journal article)

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, v. 240, p. 405-422. (on-line abstract)

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, v. 104, no. 2, p. 103-104.

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, v. 65, no. 3, p. 450-466. (on-line abstract of journal article)

McLaughlin, S.P. and Bowers, J.E., 2006, Plant species richness at different scales in native and exotic grasslands in southeastern Arizona: Western North American Naturalist, v. 66, p. 209-221.

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, v. 33, p. 342-360. (on-line abstract of journal article)

Parks, J.A., Dean, J.S., and Betancourt, J.L., 2006, Tree rings, drought and the Pueblo abandonment in south-central New Mexico during the 1670s, in Doyel, D.E., and Dean, J.S, eds., Environmental Change and Human Adaptation in the Ancient Southwest: Salt Lake City, University of Utah Press.

Pederson, G.T., Gray, S.T., Fagre, D.B., and Graumlich, L.J., 2006, Long-duration drought variability and impacts on ecosystem services: Earth Interactions, v. 10, p. 1-28. (on-line abstract of journal article)

Smith, F.A., and Betancourt, J.L., 2006, Predicting woodrat (Neotoma ) responses to anthropogenic warming from studies of the paleomidden record: Journal of Biogeography, v. 33, no. 12, p. 2,061-2,076. (on-line abstract of journal article)

Woodhouse, C.A., Gray, S.T., and Meko, D.M., 2006, Updated streamflow reconstructions for the upper Colorado River basin: Water Resources Research, v. 42, doi:10.1029/2005WR004455. (on-line abstract of journal article)

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. national phenology network: Eos Transactions American Geophysical Union, v. 86, p. 539, 542. (on-line report in pdf format, 261 KB)

Bowers, J.E., 2005, New evidence for persistent or transient seed banks in three Sonoran Desert cacti: Southwestern Naturalist, v. 50, no. 4, p. 482-487. (on-line abstract of journal article).

Bowers, J.E., 2005. El Niño and displays of spring-flowering annuals in the Mojave and Sonoran deserts: Journal of the Torrey Botanical Society, v. 132, p. 38-49. (on-line abstract or on-line journal article in pdf format)

Bowers, J.E., 2005, Influence of climatic variability on local population dynamics of a Sonoran Desert platyopuntia: Journal of Arid Environments, v. 61, p. 193-210. (on-line abstract or on-line journal article in pdf format)

Jackson, S.T., Betancourt, J.L., Lyford, M.E., and 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, v. 32, p. 1,085-1,106. (on-line abstract of journal article)

Latorre, C.L., Betancourt, J.L., Rech, J.A., Quade, J., Holmgren, C., Placzek, C.P., Vuille, M., and Rylander, K.A. 2005, Late Quaternary history of the Atacama Desert, in Smith, M., and Hesse, P., eds., 23 Degrees South: Archaeology and Environmental History of the Southern Deserts: Canberra, National Museum of Australia, p. 73-90.

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 (25º30'S): Journal of Quaternary Science, v. 20, no. 5, p. 493-507. (on-line abstract of journal article)

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,v. 32, p.1,061-1,075. (on-line abstract of journal article)

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, v. 3, p. 183-194. (on-line abstract)

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: Sunderland, Sinauer Associates, p. 27-46.

Bowers, J.E., 2004, The best spring ever - Why El Niño makes the desert bloom: Sacramento, California, California Native Plant Society.

Bowers, J.E., 2004, Temporal variation in longevity of Opuntia engelmannii (Cactaceae) flowers: Madroño, v. 51, p. 280-285. (on-line abstract)

Bowers, J.E., 2004, Diversified germination behavior of Parkinsonia microphylla (foothill paloverde, Fabaceae): Madroño, v. 51, p. 286-291. (on-line abstract)

Bowers, J.E., 2004, Frequently asked questions about the Saguaro: Tucson, Western National Parks Association, 20 p. (on-line information)

Bowers, J.E., Turner, R.M., and Burgess, T.L., 2004, Temporal and spatial patterns in emergence and early survival of perennial plants in the Sonora Desert: Plant Ecology, v. 172, no. 1, p. 107-119. (on-line abstract)

Gray, S.T., Fastie, C.L., Jackson, S.T., and Betancourt, J.L., 2004, Tree-ring-based reconstruction of precipitation in the Bighorn Basin, Wyoming, since 1260 A.D.: Journal of Climate, v. 17, p. 3,855-3,865. (on-line abstract)

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, v. 31, doi:10.1029/2004GL019932. (on-line abstract or on-line publication in pdf format)

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, v. 40, p. 947-960. (on-line abstract or on journal article in pdf format)

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 (letter): Science, v. 306, p. 1,289.

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 USA, v. 101, p. 4,136-4,141. (on-line abstract or lon-line publication in pdf format)

Betancourt, J. L., 2003, Review of "Relation of 'Bonito' paleo-channels and base-level variations to Anasazi occupation, Chaco Canyon, New Mexico" by E.R. Force and others: Progress in Physical Geography , v. 27, no. 2, p. 308-309. (on-line book review)

Betancourt, J.L., Grissino-Mayer, H.D., Salzer, M.W., and Swetnam, T.W., 2003, Reply to Genty and Baker: Quaternary Research, v. 59, p. 479.

Gray, S.T., Betancourt, J.L., Fastie, C.L., and 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, v. 30, no. 6, p. 49-1 - 49-4. (on-line abstract)

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, v. 59, p. 364-378. (on-line abstract)

Holmgren, C., Peñalba, M. C., Rylander, K. A., and Betancourt, J. L., 2003, A 16,000 14C yr B.P. packrat midden series from the U.S.A-Mexico Borderlands: Quaternary Research, v. 60, p. 319-329. (on-line abstract or on-line paper in pdf format)

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 (22-23oS): Paleogeography, Paleoclimatology, Paleoecology, v. 194, p. 223-246. (on-line abstract)

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, v. 73, p. 567–583. (on-line abstract)

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 Greenland, D., ed., Climate variability and ecosystem response at Long-Term Ecological Research (LTER) sites: Oxford University Press, p. 286-307.

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, v. 194, p. 207-222. (on-line abstract)

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, v. 59, no. 2, p. 160-171. (on-line abstract)

Turner, R.M., Webb, R.H., Bowers, J.E., and Hastings, J.R., 2003, The Changing Mile Revisited: Tucson, University of Arizona Press, 334 p. (on-line information)

Julio L. Betancourt
U.S. Geological Survey, Desert Laboratory, 1675 W. Anklam Rd., Tucson, AZ 85745
Telephone: 602-670-6821 (ext. 109)

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