Student Intersite Comparisons

Network News Spring 1996, Vol. 19 No. 1

Fall 1995 Travel Awards

In response to a 1994 request by the LTER Graduate Student Committee, the LTER Executive Committee approved the use 0fLTER Network Office funds to support student travel to LTER sites for intersite comparison work. Fall 1995 student proposals were reviewed by the Executive Committee and awarded February 1, 1996.

Cross-Site Comparisons of Two Important C4 Perennial Grasses in North American Grasslands

Tamera J. Minnick
Ph.D. candidate, Colorado State University (Ecology)

Bouteloua gracilis and Bouteloua eriopoda are two important perennial grasses in North American grassland ecosystems. Both are C4 perennial bunchgrasses that tolerate high temperature and low moisture regimes, yet their geographic distributions differ remarkably: Bouteloua gracilis is distributed throughout the central grasslands of Canada, the United States and Mexico and B. eriopoda is limited to the U.S. Southwest and Mexico. The LTER Network is the ideal system for comparing these species, since B. gracilis dominates the Central Plains Experimental Range (CPR), B. eriopoda dominates the remnant grassland portion of the Jornada, and both are found in abundance at the Sevilleta (SEV). The general objective of my doctoral research is to investigate effects of disturbance, environmental constraints, and competition on the distribution and abundance of these two important North American species. I will combine field experiments with simulation modeling to address site- and regional-level questions across an environmental gradient that includes these three LTER sites. I want to know how these patterns can explain the current and predict the future geographic distributions and abundances of the two species. I am also examining experimentally the role of competition at CPR and SEV to determine the influences of inter- and intraspecific competition, the physical environment and the interactions of these on the distributions and abundances of B. eripoda and B. gracilis. By using a variety of approaches at different spatial and temporal scales, my goal is to determine relative effects of disturbance, environmental constraints, and competition on the distribution and abundances of these two important North American perennial grasses.

Local Adaptation of Hymenolepis citelli in Ground Squirrels

L. Dwight Floyd
Ph.D. candidate, Colorado State University (Zoology)

Ground squirrels (Spermophilus spp.) cover a wide range in western North America from the Arctic to northern Mexico. Across their range, the ground squirrels may vary in a number of ways, but particularly with respect to hibernation regimes. These differences may occur between species but also within species along latitudinal and altitudinal gradients. Despite these differences in life history, Hymenolepis citelli (a tapeworm) is found in all species of ground squirrel. The purpose of this study is to determine how H. citelli reacts to these differences in their ground squirrel hosts and how the ground squirrels react to different parasite populations. These differences should help to determine the extent of local adaptation in parasite and host populations. Ground squirrels of different species and different ranges will be captured and cross-infected with parasites of complementary geographical regions or species. Hibernation regimes may then be controlled by placing some animals in cold rooms. Host and parasite fitness will then be compared between experimental groups.


McKee, A. and F. Bierlmaier. 1987. H. J. Andrews Experimental Forest,  Oregon. Pages 11-17 in: Greenland, D. (ed). The Climates of the Long-Term Ecological Research Sites. Occas. Pap. 44. Institute of Arctic and  Alpine Research, University of Colorado: Boulder. 81 pp.

Swift, L.W. 1987. Coweeta Hydrologic Laboratory, North Carolina. Pages  28-33 in: Greenland, D. (ed). The climates of the Long-Term Ecological  Research Sites. Occas. Pap. 44. Institute of Arctic and Alpine  Research, University of Colorado: Boulder. 81 pp.

Ziemer, R.R. and J.S. Albright. 1987. Subsurface pipeflow dynamics of north-coastal California swale systems. Pages 7 1-80 in: R. Beschta, T. Blinn, G.E. Grant, F.J. Swanson and G.G. Ice (eds). Erosion and Sedimentation in the Pacific Rim (Proceedings of the Corvallis Symposium, August, 1987). International Association of Hydrological Sciences Pub. No. 165.

Federer, CA., L.D. Flynn, C.W. Martin, J.W. Hornbeck and R.S. Pierce. 1990. Thirty Years of Hydrometeorological Data at the Hubbard Brook Experimental Forest, New Hampshire. Gen, T  ech. Rep. NE-141. USDA Forest Service, Northeastern Forest Experiment Station: Radnor, PA. 44pp.

Bierlmaier, F.A. and McKee, A. 1989. Climatic summaries and documentation for the primary meteorological station, H. J. Andrews Experimental Forest, 1972 to 1984. Gen. Tech. Rep. PNW-242. USDA Forest Service, Pacific Northwest Research Station: Portland, OR. 56 pp.

Swift, LW., W.T. Swank, J.B. Mankin, T.J. Luxmorre and R.A. Goldstein. 1975. Simulation of evapotranspiration and drainage from mature and clear-cut deciduous forests and young pine plantation. Water Resources Research 11(5): 667-673.

Federer, CA. 1982. Improving forest hydrology research. Pages 653-663 in: Canadian Hydrology Symp. 82, National Research Council of Canada. Fredricton, New Brunswick.