URSULA L. SHEPHERD
Associate Professor, University Honors Program, University of New Mexico
Research Assistant Professor, Department of Biology, University of New Mexico

Ph.D. Biology. University of New Mexico, 1994
B.S. equivalent Biology. University of New Mexico, 1987
M.A. Social Sciences and Communication Arts. University of the Pacific, 1973
B.A. Social Sciences. University of the Pacific, 1966

Research interests and focus: Diversity of communities across gradients. What governs the diversity of species in a given location?

Publications

Shepherd, U.L. and Brantley, S.L. 2005. Expanding on Watson's framework for classifying patches: When is an island not an island? Journal of Biogeography 32:951-960.

Brantley, S.L., and U.L. Shepherd. 2004. Effect of cryptobiotic cruts type on microarthropod assemblages in pinion-juniper woodlands in central New Mexico. Western North American Naturalist 64:155-164.

Shepherd, U., S. Brantley, and C. Tarleton.¹ 2002. Species richness and abundance patterns of microarthropods on cryptobiotic crusts in a piñon-juniper habitat: a call for greater knowledge. Journal of Arid Environments 52:349-360.

Koontz¹, T., U. Shepherd, and D. Marshall. 2001. The effects of climate change on Merriam's kangaroo rat, Dipodomys merriami. Journal of Arid Environments 49:581-591.

Shepherd, U. 2000. Creative Approaches to Teaching Science in an Honors Setting. National Collegiate Honors Council Forum 1:53-61.

Shepherd, U. and D. Kelt. 1999. Morphological Diversity of Mammal Communities at Deep Canyon, California. Journal of Biogeography 26: 843-855.

Shepherd, U. 1999. Biological Diversity of Tropical Australia: A Summer Field Experience for Honors Undergraduates. The National Honors Report 20: 36-39.

Shepherd, U. 1998. Changes in Species Richness and Morphological Complexity across the North American latitudinal gradient. Journal of Biogeography 25:19-29.

Smith, F.A., H. Browning and U. Shepherd. 1998. The influence of climate change on body mass of woodrat (Neotoma) populations at the Sevilleta National Wildlife Refuge, New Mexico, USA Ecography 21: 140-148.

Mehlman, D., U. Shepherd and D. Kelt. 1995. Bootstrapping principal components analysis: Reflections on Jackson. Ecology 76: 640-643.

Shepherd, U. and M. O'Brien. 1990. Nature Notes: A Companion to the Seasons. Fulcrum Publishing, Golden, Co.

Ph.D. Biology. University of New Mexico, 1999
B.S. Biology. University of Utah, 1994

Research interests and focus: Physiological ecology of plant species, environmental control of physiological activity, primarily carbon acquisition and water use.

Publications

Leffler, A.J. and Caldwell, M.M. 2005. Photosynthetic capacity and relative depth of water extraction along an ecotone of Juniperus osteosperma (Utah juniper) and Artemisia tridentata (big sagebrush). Journal of Ecology 93:783-793.

Leffler, A.J., Peek, M.S., Ryel, R.J., Ivans, C.Y. and Caldwell, M.M. 2005. Hydraulic redistribution through the root systems of senesced plants. Ecology 86:633-642.

Peek, M.S., Leffler, A.J., Ivans, C.Y., Ryel, R.J. and Caldwell, M.M. 2005. Fine root distribution and persistence under field conditions of three co-occurring Great Basin species of different life form. New Phytologist 165:171-180.

Huxman, T.E., Snyder, K., Tissue, D., Leffler, A.J., Ogle, K., Pockman, W.T., Sandquist, D.R., Potts, D.L. and Schwinning, S. 2004. Precipitation pulses and carbon fluxes in semiarid and arid ecosystems. Oecologia 141:254-268.

Ryel, R.J., Leffler, A.J., Peek, M.S., Ivans, C.Y. and Caldwell, M.M. 2004. Water conservation in Artemisia tridentata through redistribution of precipitation. Oecologia 141:335-345.

Leffler, A.J., Ivans, C.Y., Ryel, R.J. and Caldwell, M.M. 2004. Gas exchange and growth responses of the desert shrubs Artemisia tridentata and Chrysothamnus nauseosus to shallow- versus deep-soil water in a glasshouse experiment. Environmental and Experimental Botany 51:9-19.

Peek, M.S., Leffler, A.J., Flint, S.D. and Ryel, R.J. 2003. How much variance is not explained by ecologists: Additional perspectives. Oecologia 137:161-170.

Ryel, R.J., Caldwell, M.M., Leffler, A.J., and Yoder, C.K. 2003. Rapid soil moisture recharge to depth by roots. Ecology 84:757-764.

Ivans, C.Y., Leffler, A.J., Spaulding, U., Stark, J.M., Ryel, R. and Caldwell, M.M. 2003. Root responses and nitrogen acquisition by Artemisia tridentata and Agropyron desertorum following small summer rainfall events. Oecologia 134:317-324.

Leffler, A.J., Ryel, R.J., Hipps, L., Ivans, S., Caldwell, M.M. 2002. Carbon acquisition and water use in a northern Utah Juniperus osteosperma (Utah juniper) population. Tree Physiology 22:1221-1230.

Ryel, R.J., Caldwell, M.M., Yoder, C.K., Or, D. and Leffler, A.J. 2002. Hydraulic redistribution in a stand of Artemisia tridentata: Evaluation of benefits to transpiration assessed with a simulation model. Oecologia 130:173-184.

Leffler, A.J. and Enquist, B.J. 2002. Carbon isotope composition of tree leaves from dry tropical forests of Guanacaste, Costa Rica: Comparison across tropical ecosystems and tree life history. Journal of Tropical Ecology 18:151-159.

Leffler, A.J. and Evans, A.S. 2001. Physiological variation among Populus fremontii populations: Short- and long-term relationships between d¹³C and water availability. Tree Physiology 21:1149-1155.

Enquist, B.J. and Leffler, A.J. 2001. Long-term tree ring chronologies from sympatric tropical dry-forest trees: Individualistic responses to climatic variation. Journal of Tropical Ecology 17:41-60.

Leffler, A.J., England, L.E. and Naito, J.N. 2000. Vulnerability of Fremont cottonwood individuals to xylem cavitation. Western North American Naturalist 60:204-210.

Leffler, A.J. and Evans, A.S. 1999. Variation in carbon isotope composition among years in the riparian tree Populus fremontii. Oecologia 119:311-319.